From 662fde90774af7779c542c05f9402acb4ffcb297 Mon Sep 17 00:00:00 2001 From: Imre Kaloz Date: Sat, 3 Mar 2007 20:35:01 +0000 Subject: [PATCH] R.I.P. devfs SVN-Revision: 6478 --- package/base-files/files/etc/inittab | 2 +- package/base-files/files/etc/mdev.conf | 5 + package/base-files/files/sbin/hotplug | 2 + package/busybox/Makefile | 1 + package/busybox/config/miscutils/Config.in | 2 +- package/busybox/config/util-linux/Config.in | 4 +- package/busybox/target-config.in | 11 + target/linux/generic-2.6/files/init | 15 +- .../patches/000-reinstate-devfs.patch | 12377 ---------------- .../generic-2.6/patches/008-mtd_uaccess.patch | 15 - 10 files changed, 36 insertions(+), 12398 deletions(-) create mode 100644 package/base-files/files/etc/mdev.conf create mode 100644 package/busybox/target-config.in delete mode 100644 target/linux/generic-2.6/patches/000-reinstate-devfs.patch delete mode 100644 target/linux/generic-2.6/patches/008-mtd_uaccess.patch diff --git a/package/base-files/files/etc/inittab b/package/base-files/files/etc/inittab index 39e134cb16af..3d92717c9dd4 100644 --- a/package/base-files/files/etc/inittab +++ b/package/base-files/files/etc/inittab @@ -1,3 +1,3 @@ ::sysinit:/etc/init.d/rcS tts/0::askfirst:/bin/ash --login -#tts/1::askfirst:/bin/ash --login +ttyS0::askfirst:/bin/ash --login diff --git a/package/base-files/files/etc/mdev.conf b/package/base-files/files/etc/mdev.conf new file mode 100644 index 000000000000..89355830f0fc --- /dev/null +++ b/package/base-files/files/etc/mdev.conf @@ -0,0 +1,5 @@ +null 0:0 777 +zero 0:0 666 +console 0:5 0600 +tty 0:5 0660 +ttyS* 0:20 640 diff --git a/package/base-files/files/sbin/hotplug b/package/base-files/files/sbin/hotplug index b1b6f97b2348..75d5170833c7 100755 --- a/package/base-files/files/sbin/hotplug +++ b/package/base-files/files/sbin/hotplug @@ -1,6 +1,8 @@ #!/bin/sh # Copyright (C) 2006 OpenWrt.org +[ -x /sbin/mdev ] && /sbin/mdev "$@" + # bypass the normal hotplug path for firmware loading # would otherwise cause problems with drivers like bcm43xx [ "$1" = "firmware" -a "$ACTION" = "add" ] && { diff --git a/package/busybox/Makefile b/package/busybox/Makefile index 530b0276706d..3e6cc4e9c920 100644 --- a/package/busybox/Makefile +++ b/package/busybox/Makefile @@ -41,6 +41,7 @@ The Swiss Army Knife of embedded Linux. endef define Package/busybox/config + source "$(SOURCE)/target-config.in" menu "Configuration" depends on PACKAGE_busybox source "$(SOURCE)/config/Config.in" diff --git a/package/busybox/config/miscutils/Config.in b/package/busybox/config/miscutils/Config.in index 41a42c91a13c..4e418893f4ff 100644 --- a/package/busybox/config/miscutils/Config.in +++ b/package/busybox/config/miscutils/Config.in @@ -105,7 +105,7 @@ config BUSYBOX_CONFIG_DEVFSD_VERBOSE config BUSYBOX_CONFIG_FEATURE_DEVFS bool " Use devfs names for all devices (obsolete)" - default y + default n help This is obsolete and will be going away at the end of 2008.. diff --git a/package/busybox/config/util-linux/Config.in b/package/busybox/config/util-linux/Config.in index ab3dc3731dd4..0f219d70e244 100644 --- a/package/busybox/config/util-linux/Config.in +++ b/package/busybox/config/util-linux/Config.in @@ -267,7 +267,7 @@ config BUSYBOX_CONFIG_LOSETUP config BUSYBOX_CONFIG_MDEV bool "mdev" - default n + default y help mdev is a mini-udev implementation: call it with -s to populate /dev from /sys, then "echo /sbin/mdev > /proc/sys/kernel/hotplug" to @@ -276,7 +276,7 @@ config BUSYBOX_CONFIG_MDEV config BUSYBOX_CONFIG_FEATURE_MDEV_CONF bool "Support /etc/mdev.conf" - default n + default y depends on BUSYBOX_CONFIG_MDEV help The mdev config file contains lines that look like: diff --git a/package/busybox/target-config.in b/package/busybox/target-config.in new file mode 100644 index 000000000000..77c58cef1423 --- /dev/null +++ b/package/busybox/target-config.in @@ -0,0 +1,11 @@ +config BUSYBOX_CONFIG_FEATURE_DEVFS + default y if LINUX_2_4 + default n if LINUX_2_6 + +config BUSYBOX_CONFIG_MDEV + default n if LINUX_2_4 + default y if LINUX_2_6 + +config BUSYBOX_CONFIG_FEATURE_MDEV_CONF + default n if LINUX_2_4 + default y if LINUX_2_6 diff --git a/target/linux/generic-2.6/files/init b/target/linux/generic-2.6/files/init index 1fa6a7f1f61b..292d429dcd5e 100755 --- a/target/linux/generic-2.6/files/init +++ b/target/linux/generic-2.6/files/init @@ -3,8 +3,19 @@ export PATH=/bin:/sbin:/usr/bin:/usr/sbin mount none /proc -t proc -mount none /dev -t devfs -mount non /dev/pts -t devpts + +if grep devfs /proc/filesystems > /dev/null; then + mount none /dev -t devfs +else + mount -t sysfs none /sys + mount -t tmpfs tmpfs /dev -o size=512K + mknod /dev/console c 5 1 + mkdir /dev/pts + mkdir /dev/shm + /sbin/mdev -s +fi + +mount none /dev/pts -t devpts # the root mount point can come from the kernel command line # or it can be overridden in the preinit.arch file diff --git a/target/linux/generic-2.6/patches/000-reinstate-devfs.patch b/target/linux/generic-2.6/patches/000-reinstate-devfs.patch deleted file mode 100644 index 5429a0e4b0a8..000000000000 --- a/target/linux/generic-2.6/patches/000-reinstate-devfs.patch +++ /dev/null @@ -1,12377 +0,0 @@ -diff -urN linux-2.6.19.old/arch/cris/arch-v10/kernel/debugport.c linux-2.6.19.dev/arch/cris/arch-v10/kernel/debugport.c ---- linux-2.6.19.old/arch/cris/arch-v10/kernel/debugport.c 2006-11-29 22:57:37.000000000 +0100 -+++ linux-2.6.19.dev/arch/cris/arch-v10/kernel/debugport.c 2006-12-14 03:12:59.000000000 +0100 -@@ -540,7 +540,7 @@ - dummy_driver.init_termios = tty_std_termios; - dummy_driver.init_termios.c_cflag = - B115200 | CS8 | CREAD | HUPCL | CLOCAL; /* is normally B9600 default... */ -- dummy_driver.flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV; -+ dummy_driver.flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_NO_DEVFS; - - dummy_driver.open = dummy_open; - dummy_driver.close = dummy_close; -diff -urN linux-2.6.19.old/arch/cris/arch-v32/kernel/debugport.c linux-2.6.19.dev/arch/cris/arch-v32/kernel/debugport.c ---- linux-2.6.19.old/arch/cris/arch-v32/kernel/debugport.c 2006-11-29 22:57:37.000000000 +0100 -+++ linux-2.6.19.dev/arch/cris/arch-v32/kernel/debugport.c 2006-12-14 03:12:59.000000000 +0100 -@@ -352,7 +352,7 @@ - dummy_driver.init_termios = tty_std_termios; - dummy_driver.init_termios.c_cflag = - B115200 | CS8 | CREAD | HUPCL | CLOCAL; /* is normally B9600 default... */ -- dummy_driver.flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV; -+ dummy_driver.flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_NO_DEVFS; - - dummy_driver.open = dummy_open; - dummy_driver.close = dummy_close; -diff -urN linux-2.6.19.old/arch/i386/kernel/microcode.c linux-2.6.19.dev/arch/i386/kernel/microcode.c ---- linux-2.6.19.old/arch/i386/kernel/microcode.c 2006-11-29 22:57:37.000000000 +0100 -+++ linux-2.6.19.dev/arch/i386/kernel/microcode.c 2006-12-14 03:12:59.000000000 +0100 -@@ -460,6 +460,7 @@ - static struct miscdevice microcode_dev = { - .minor = MICROCODE_MINOR, - .name = "microcode", -+ .devfs_name = "cpu/microcode", - .fops = µcode_fops, - }; - -diff -urN linux-2.6.19.old/arch/ppc/4xx_io/serial_sicc.c linux-2.6.19.dev/arch/ppc/4xx_io/serial_sicc.c ---- linux-2.6.19.old/arch/ppc/4xx_io/serial_sicc.c 2006-11-29 22:57:37.000000000 +0100 -+++ linux-2.6.19.dev/arch/ppc/4xx_io/serial_sicc.c 2006-12-14 03:12:59.000000000 +0100 -@@ -1757,7 +1757,7 @@ - siccnormal_driver->subtype = SERIAL_TYPE_NORMAL; - siccnormal_driver->init_termios = tty_std_termios; - siccnormal_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL; -- siccnormal_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV; -+ siccnormal_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_NO_DEVFS; - tty_set_operations(siccnormal_driver, &sicc_ops); - - if (tty_register_driver(siccnormal_driver)) -diff -urN linux-2.6.19.old/arch/sparc64/solaris/socksys.c linux-2.6.19.dev/arch/sparc64/solaris/socksys.c ---- linux-2.6.19.old/arch/sparc64/solaris/socksys.c 2006-11-29 22:57:37.000000000 +0100 -+++ linux-2.6.19.dev/arch/sparc64/solaris/socksys.c 2006-12-14 03:12:59.000000000 +0100 -@@ -26,6 +26,7 @@ - #include - #include - #include -+#include - - #include - -@@ -188,6 +189,8 @@ - return ret; - } - -+ devfs_mk_cdev(MKDEV(30, 0), S_IFCHR|S_IRUSR|S_IWUSR, "socksys"); -+ - file = fcheck(ret); - /* N.B. Is this valid? Suppose the f_ops are in a module ... */ - socksys_file_ops = *file->f_op; -@@ -202,4 +205,5 @@ - { - if (unregister_chrdev(30, "socksys")) - printk ("Couldn't unregister socksys character device\n"); -+ devfs_remove ("socksys"); - } -diff -urN linux-2.6.19.old/arch/um/drivers/line.c linux-2.6.19.dev/arch/um/drivers/line.c ---- linux-2.6.19.old/arch/um/drivers/line.c 2006-11-29 22:57:37.000000000 +0100 -+++ linux-2.6.19.dev/arch/um/drivers/line.c 2006-12-14 03:12:59.000000000 +0100 -@@ -8,6 +8,7 @@ - #include "linux/list.h" - #include "linux/kd.h" - #include "linux/interrupt.h" -+#include "linux/devfs_fs_kernel.h" - #include "asm/uaccess.h" - #include "chan_kern.h" - #include "irq_user.h" -@@ -653,6 +654,7 @@ - - driver->driver_name = line_driver->name; - driver->name = line_driver->device_name; -+ driver->devfs_name = line_driver->devfs_name; - driver->major = line_driver->major; - driver->minor_start = line_driver->minor_start; - driver->type = line_driver->type; -diff -urN linux-2.6.19.old/arch/um/drivers/ssl.c linux-2.6.19.dev/arch/um/drivers/ssl.c ---- linux-2.6.19.old/arch/um/drivers/ssl.c 2006-11-29 22:57:37.000000000 +0100 -+++ linux-2.6.19.dev/arch/um/drivers/ssl.c 2006-12-14 03:12:59.000000000 +0100 -@@ -53,6 +53,7 @@ - static struct line_driver driver = { - .name = "UML serial line", - .device_name = "ttyS", -+ .devfs_name = "tts/", - .major = TTY_MAJOR, - .minor_start = 64, - .type = TTY_DRIVER_TYPE_SERIAL, -diff -urN linux-2.6.19.old/arch/um/drivers/stdio_console.c linux-2.6.19.dev/arch/um/drivers/stdio_console.c ---- linux-2.6.19.old/arch/um/drivers/stdio_console.c 2006-11-29 22:57:37.000000000 +0100 -+++ linux-2.6.19.dev/arch/um/drivers/stdio_console.c 2006-12-14 03:12:59.000000000 +0100 -@@ -59,6 +59,7 @@ - static struct line_driver driver = { - .name = "UML console", - .device_name = "tty", -+ .devfs_name = "vc/", - .major = TTY_MAJOR, - .minor_start = 0, - .type = TTY_DRIVER_TYPE_CONSOLE, -diff -urN linux-2.6.19.old/arch/um/drivers/ubd_kern.c linux-2.6.19.dev/arch/um/drivers/ubd_kern.c ---- linux-2.6.19.old/arch/um/drivers/ubd_kern.c 2006-11-29 22:57:37.000000000 +0100 -+++ linux-2.6.19.dev/arch/um/drivers/ubd_kern.c 2006-12-14 03:12:59.000000000 +0100 -@@ -24,6 +24,7 @@ - #include "linux/blkdev.h" - #include "linux/hdreg.h" - #include "linux/init.h" -+#include "linux/devfs_fs_kernel.h" - #include "linux/cdrom.h" - #include "linux/proc_fs.h" - #include "linux/ctype.h" -@@ -645,10 +646,14 @@ - disk->first_minor = unit << UBD_SHIFT; - disk->fops = &ubd_blops; - set_capacity(disk, size / 512); -- if(major == MAJOR_NR) -+ if(major == MAJOR_NR){ - sprintf(disk->disk_name, "ubd%c", 'a' + unit); -- else -+ sprintf(disk->devfs_name, "ubd/disc%d", unit); -+ } -+ else { - sprintf(disk->disk_name, "ubd_fake%d", unit); -+ sprintf(disk->devfs_name, "ubd_fake/disc%d", unit); -+ } - - /* sysfs register (not for ide fake devices) */ - if (major == MAJOR_NR) { -@@ -853,6 +864,7 @@ - { - int i; - -+ devfs_mk_dir("ubd"); - if (register_blkdev(MAJOR_NR, "ubd")) - return -1; - -@@ -866,6 +878,7 @@ - char name[sizeof("ubd_nnn\0")]; - - snprintf(name, sizeof(name), "ubd_%d", fake_major); -+ devfs_mk_dir(name); - if (register_blkdev(fake_major, "ubd")) - return -1; - } -diff -urN linux-2.6.19.old/arch/um/include/line.h linux-2.6.19.dev/arch/um/include/line.h ---- linux-2.6.19.old/arch/um/include/line.h 2006-11-29 22:57:37.000000000 +0100 -+++ linux-2.6.19.dev/arch/um/include/line.h 2006-12-14 03:12:59.000000000 +0100 -@@ -17,6 +17,7 @@ - struct line_driver { - char *name; - char *device_name; -+ char *devfs_name; - short major; - short minor_start; - short type; -diff -urN linux-2.6.19.old/Documentation/Changes linux-2.6.19.dev/Documentation/Changes ---- linux-2.6.19.old/Documentation/Changes 2006-11-29 22:57:37.000000000 +0100 -+++ linux-2.6.19.dev/Documentation/Changes 2006-12-14 03:12:59.000000000 +0100 -@@ -180,8 +180,8 @@ - -------------------- - - A driver has been added to allow updating of Intel IA32 microcode, --accessible as a normal (misc) character device. If you are not using --udev you may need to: -+accessible as both a devfs regular file and as a normal (misc) -+character device. If you are not using devfs you may need to: - - mkdir /dev/cpu - mknod /dev/cpu/microcode c 10 184 -@@ -200,9 +200,7 @@ - udev - ---- - udev is a userspace application for populating /dev dynamically with --only entries for devices actually present. udev replaces the basic --functionality of devfs, while allowing persistant device naming for --devices. -+only entries for devices actually present. udev replaces devfs. - - FUSE - ---- -@@ -232,13 +230,18 @@ - enable it to operate over diverse media layers. If you use PPP, - upgrade pppd to at least 2.4.0. - --If you are not using udev, you must have the device file /dev/ppp -+If you are not using devfs, you must have the device file /dev/ppp - which can be made by: - - mknod /dev/ppp c 108 0 - - as root. - -+If you use devfsd and build ppp support as modules, you will need -+the following in your /etc/devfsd.conf file: -+ -+LOOKUP PPP MODLOAD -+ - Isdn4k-utils - ------------ - -diff -urN linux-2.6.19.old/Documentation/DocBook/kernel-api.tmpl linux-2.6.19.dev/Documentation/DocBook/kernel-api.tmpl ---- linux-2.6.19.old/Documentation/DocBook/kernel-api.tmpl 2006-11-29 22:57:37.000000000 +0100 -+++ linux-2.6.19.dev/Documentation/DocBook/kernel-api.tmpl 2006-12-14 03:12:59.000000000 +0100 -@@ -84,6 +84,9 @@ - !Ekernel/rcupdate.c - - -+ -+ The Device File System -+!Efs/devfs/base.c - - - -diff -urN linux-2.6.19.old/Documentation/filesystems/devfs/boot-options linux-2.6.19.dev/Documentation/filesystems/devfs/boot-options ---- linux-2.6.19.old/Documentation/filesystems/devfs/boot-options 1970-01-01 01:00:00.000000000 +0100 -+++ linux-2.6.19.dev/Documentation/filesystems/devfs/boot-options 2006-12-14 03:12:59.000000000 +0100 -@@ -0,0 +1,65 @@ -+/* -*- auto-fill -*- */ -+ -+ Device File System (devfs) Boot Options -+ -+ Richard Gooch -+ -+ 18-AUG-2001 -+ -+ -+When CONFIG_DEVFS_DEBUG is enabled, you can pass several boot options -+to the kernel to debug devfs. The boot options are prefixed by -+"devfs=", and are separated by commas. Spaces are not allowed. The -+syntax looks like this: -+ -+devfs=,, -+ -+and so on. For example, if you wanted to turn on debugging for module -+load requests and device registration, you would do: -+ -+devfs=dmod,dreg -+ -+You may prefix "no" to any option. This will invert the option. -+ -+ -+Debugging Options -+================= -+ -+These requires CONFIG_DEVFS_DEBUG to be enabled. -+Note that all debugging options have 'd' as the first character. By -+default all options are off. All debugging output is sent to the -+kernel logs. The debugging options do not take effect until the devfs -+version message appears (just prior to the root filesystem being -+mounted). -+ -+These are the options: -+ -+dmod print module load requests to -+ -+dreg print device register requests to -+ -+dunreg print device unregister requests to -+ -+dchange print device change requests to -+ -+dilookup print inode lookup requests -+ -+diget print VFS inode allocations -+ -+diunlink print inode unlinks -+ -+dichange print inode changes -+ -+dimknod print calls to mknod(2) -+ -+dall some debugging turned on -+ -+ -+Other Options -+============= -+ -+These control the default behaviour of devfs. The options are: -+ -+mount mount devfs onto /dev at boot time -+ -+only disable non-devfs device nodes for devfs-capable drivers -diff -urN linux-2.6.19.old/Documentation/filesystems/devfs/ChangeLog linux-2.6.19.dev/Documentation/filesystems/devfs/ChangeLog ---- linux-2.6.19.old/Documentation/filesystems/devfs/ChangeLog 1970-01-01 01:00:00.000000000 +0100 -+++ linux-2.6.19.dev/Documentation/filesystems/devfs/ChangeLog 2006-12-14 03:12:59.000000000 +0100 -@@ -0,0 +1,1977 @@ -+/* -*- auto-fill -*- */ -+=============================================================================== -+Changes for patch v1 -+ -+- creation of devfs -+ -+- modified miscellaneous character devices to support devfs -+=============================================================================== -+Changes for patch v2 -+ -+- bug fix with manual inode creation -+=============================================================================== -+Changes for patch v3 -+ -+- bugfixes -+ -+- documentation improvements -+ -+- created a couple of scripts (one to save&restore a devfs and the -+ other to set up compatibility symlinks) -+ -+- devfs support for SCSI discs. New name format is: sd_hHcCiIlL -+=============================================================================== -+Changes for patch v4 -+ -+- bugfix for the directory reading code -+ -+- bugfix for compilation with kerneld -+ -+- devfs support for generic hard discs -+ -+- rationalisation of the various watchdog drivers -+=============================================================================== -+Changes for patch v5 -+ -+- support for mounting directly from entries in the devfs (it doesn't -+ need to be mounted to do this), including the root filesystem. -+ Mounting of swap partitions also works. Hence, now if you set -+ CONFIG_DEVFS_ONLY to 'Y' then you won't be able to access your discs -+ via ordinary device nodes. Naturally, the default is 'N' so that you -+ can still use your old device nodes. If you want to mount from devfs -+ entries, make sure you use: append = "root=/dev/sd_..." in your -+ lilo.conf. It seems LILO looks for the device number (major&minor) -+ and writes that into the kernel image :-( -+ -+- support for character memory devices (/dev/null, /dev/zero, /dev/full -+ and so on). Thanks to C. Scott Ananian -+=============================================================================== -+Changes for patch v6 -+ -+- support for subdirectories -+ -+- support for symbolic links (created by devfs_mk_symlink(), no -+ support yet for creation via symlink(2)) -+ -+- SCSI disc naming now cast in stone, with the format: -+ /dev/sd/c0b1t2u3 controller=0, bus=1, ID=2, LUN=3, whole disc -+ /dev/sd/c0b1t2u3p4 controller=0, bus=1, ID=2, LUN=3, 4th partition -+ -+- loop devices now appear in devfs -+ -+- tty devices, console, serial ports, etc. now appear in devfs -+ Thanks to C. Scott Ananian -+ -+- bugs with mounting devfs-only devices now fixed -+=============================================================================== -+Changes for patch v7 -+ -+- SCSI CD-ROMS, tapes and generic devices now appear in devfs -+=============================================================================== -+Changes for patch v8 -+ -+- bugfix with no-rewind SCSI tapes -+ -+- RAMDISCs now appear in devfs -+ -+- better cleaning up of devfs entries created by various modules -+ -+- interface change to -+=============================================================================== -+Changes for patch v9 -+ -+- the v8 patch was corrupted somehow, which would affect the patch for -+ linux/fs/filesystems.c -+ I've also fixed the v8 patch file on the WWW -+ -+- MetaDevices (/dev/md*) should now appear in devfs -+=============================================================================== -+Changes for patch v10 -+ -+- bugfix in meta device support for devfs -+ -+- created this ChangeLog file -+ -+- added devfs support to the floppy driver -+ -+- added support for creating sockets in a devfs -+=============================================================================== -+Changes for patch v11 -+ -+- added DEVFS_FL_HIDE_UNREG flag -+ -+- incorporated better patch for ttyname() in libc 5.4.43 from H.J. Lu. -+ -+- interface change to -+ -+- support for creating symlinks with symlink(2) -+ -+- parallel port printer (/dev/lp*) now appears in devfs -+=============================================================================== -+Changes for patch v12 -+ -+- added inode check to function -+ -+- improved devfs support when mounting from devfs -+ -+- added call to <> operation when removing swap areas on -+ devfs devices -+ -+- increased NR_SUPER to 128 to support large numbers of devfs mounts -+ (for chroot(2) gaols) -+ -+- fixed bug in SCSI disc support: was generating incorrect minors if -+ SCSI ID's did not start at 0 and increase by 1 -+ -+- support symlink traversal when mounting root -+=============================================================================== -+Changes for patch v13 -+ -+- added devfs support to soundcard driver -+ Thanks to Eric Dumas and -+ C. Scott Ananian -+ -+- added devfs support to the joystick driver -+ -+- loop driver now has it's own subdirectory "/dev/loop/" -+ -+- created and functions -+ -+- fix problem with SCSI disc compatibility names (sd{a,b,c,d,e,f}) -+ which assumes ID's start at 0 and increase by 1. Also only create -+ devfs entries for SCSI disc partitions which actually exist -+ Show new names in partition check -+ Thanks to Jakub Jelinek -+=============================================================================== -+Changes for patch v14 -+ -+- bug fix in floppy driver: would not compile without -+ CONFIG_DEVFS_FS='Y' -+ Thanks to Jurgen Botz -+ -+- bug fix in loop driver -+ Thanks to C. Scott Ananian -+ -+- do not create devfs entries for printers not configured -+ Thanks to C. Scott Ananian -+ -+- do not create devfs entries for serial ports not present -+ Thanks to C. Scott Ananian -+ -+- ensure is exported from tty_io.c -+ Thanks to C. Scott Ananian -+ -+- allow unregistering of devfs symlink entries -+ -+- fixed bug in SCSI disc naming introduced in last patch version -+=============================================================================== -+Changes for patch v15 -+ -+- ported to kernel 2.1.81 -+=============================================================================== -+Changes for patch v16 -+ -+- created function -+ -+- moved DEVFS_SUPER_MAGIC into header file -+ -+- added DEVFS_FL_HIDE flag -+ -+- created -+ -+- created -+ -+- fixed bugs in searching by major&minor -+ -+- changed interface to , and -+ -+ -+- fixed inode times when symlink created with symlink(2) -+ -+- change tty driver to do auto-creation of devfs entries -+ Thanks to C. Scott Ananian -+ -+- fixed bug in genhd.c: whole disc (non-SCSI) was not registered to -+ devfs -+ -+- updated libc 5.4.43 patch for ttyname() -+=============================================================================== -+Changes for patch v17 -+ -+- added CONFIG_DEVFS_TTY_COMPAT -+ Thanks to C. Scott Ananian -+ -+- bugfix in devfs support for drivers/char/lp.c -+ Thanks to C. Scott Ananian -+ -+- clean up serial driver so that PCMCIA devices unregister correctly -+ Thanks to C. Scott Ananian -+ -+- fixed bug in genhd.c: whole disc (non-SCSI) was not registered to -+ devfs [was missing in patch v16] -+ -+- updated libc 5.4.43 patch for ttyname() [was missing in patch v16] -+ -+- all SCSI devices now registered in /dev/sg -+ -+- support removal of devfs entries via unlink(2) -+=============================================================================== -+Changes for patch v18 -+ -+- added floppy/?u720 floppy entry -+ -+- fixed kerneld support for entries in devfs subdirectories -+ -+- incorporated latest patch for ttyname() in libc 5.4.43 from H.J. Lu. -+=============================================================================== -+Changes for patch v19 -+ -+- bug fix when looking up unregistered entries: kerneld was not called -+ -+- fixes for kernel 2.1.86 (now requires 2.1.86) -+=============================================================================== -+Changes for patch v20 -+ -+- only create available floppy entries -+ Thanks to Andrzej Krzysztofowicz -+ -+- new IDE naming scheme following SCSI format (i.e. /dev/id/c0b0t0u0p1 -+ instead of /dev/hda1) -+ Thanks to Andrzej Krzysztofowicz -+ -+- new XT disc naming scheme following SCSI format (i.e. /dev/xd/c0t0p1 -+ instead of /dev/xda1) -+ Thanks to Andrzej Krzysztofowicz -+ -+- new non-standard CD-ROM names (i.e. /dev/sbp/c#t#) -+ Thanks to Andrzej Krzysztofowicz -+ -+- allow symlink traversal when mounting the root filesystem -+ -+- Create entries for MD devices at MD init -+ Thanks to Christophe Leroy -+=============================================================================== -+Changes for patch v21 -+ -+- ported to kernel 2.1.91 -+=============================================================================== -+Changes for patch v22 -+ -+- SCSI host number patch ("scsihosts=" kernel option) -+ Thanks to Andrzej Krzysztofowicz -+=============================================================================== -+Changes for patch v23 -+ -+- Fixed persistence bug with device numbers for manually created -+ device files -+ -+- Fixed problem with recreating symlinks with different content -+ -+- Added CONFIG_DEVFS_MOUNT (mount devfs on /dev at boot time) -+=============================================================================== -+Changes for patch v24 -+ -+- Switched from CONFIG_KERNELD to CONFIG_KMOD: module autoloading -+ should now work again -+ -+- Hide entries which are manually unlinked -+ -+- Always invalidate devfs dentry cache when registering entries -+ -+- Support removal of devfs directories via rmdir(2) -+ -+- Ensure directories created by are visible -+ -+- Default no access for "other" for floppy device -+=============================================================================== -+Changes for patch v25 -+ -+- Updates to CREDITS file and minor IDE numbering change -+ Thanks to Andrzej Krzysztofowicz -+ -+- Invalidate devfs dentry cache when making directories -+ -+- Invalidate devfs dentry cache when removing entries -+ -+- More informative message if root FS mount fails when devfs -+ configured -+ -+- Fixed persistence bug with fifos -+=============================================================================== -+Changes for patch v26 -+ -+- ported to kernel 2.1.97 -+ -+- Changed serial directory from "/dev/serial" to "/dev/tts" and -+ "/dev/consoles" to "/dev/vc" to be more friendly to new procps -+=============================================================================== -+Changes for patch v27 -+ -+- Added support for IDE4 and IDE5 -+ Thanks to Andrzej Krzysztofowicz -+ -+- Documented "scsihosts=" boot parameter -+ -+- Print process command when debugging kerneld/kmod -+ -+- Added debugging for register/unregister/change operations -+ -+- Added "devfs=" boot options -+ -+- Hide unregistered entries by default -+=============================================================================== -+Changes for patch v28 -+ -+- No longer lock/unlock superblock in (cope with -+ recent VFS interface change) -+ -+- Do not automatically change ownership/protection of /dev/tty -+ -+- Drop negative dentries when they are released -+ -+- Manage dcache more efficiently -+=============================================================================== -+Changes for patch v29 -+ -+- Added DEVFS_FL_AUTO_DEVNUM flag -+=============================================================================== -+Changes for patch v30 -+ -+- No longer set unnecessary methods -+ -+- Ported to kernel 2.1.99-pre3 -+=============================================================================== -+Changes for patch v31 -+ -+- Added PID display to debugging message -+ -+- Added "diread" and "diwrite" options -+ -+- Ported to kernel 2.1.102 -+ -+- Fixed persistence problem with permissions -+=============================================================================== -+Changes for patch v32 -+ -+- Fixed devfs support in drivers/block/md.c -+=============================================================================== -+Changes for patch v33 -+ -+- Support legacy device nodes -+ -+- Fixed bug where recreated inodes were hidden -+ -+- New IDE naming scheme: everything is under /dev/ide -+=============================================================================== -+Changes for patch v34 -+ -+- Improved debugging in -+ -+- Prevent duplicate calls to in SCSI layer -+ -+- No longer free old dentries in -+ -+- Free all dentries for a given entry when deleting inodes -+=============================================================================== -+Changes for patch v35 -+ -+- Ported to kernel 2.1.105 (sound driver changes) -+=============================================================================== -+Changes for patch v36 -+ -+- Fixed sound driver port -+=============================================================================== -+Changes for patch v37 -+ -+- Minor documentation tweaks -+=============================================================================== -+Changes for patch v38 -+ -+- More documentation tweaks -+ -+- Fix for sound driver port -+ -+- Removed ttyname-patch (grab libc 5.4.44 instead) -+ -+- Ported to kernel 2.1.107-pre2 (loop driver fix) -+=============================================================================== -+Changes for patch v39 -+ -+- Ported to kernel 2.1.107 (hd.c hunk broke due to spelling "fixes"). Sigh -+ -+- Removed many #ifdef's, replaced with trickery in include/devfs_fs.h -+=============================================================================== -+Changes for patch v40 -+ -+- Fix for sound driver port -+ -+- Limit auto-device numbering to majors 128 to 239 -+=============================================================================== -+Changes for patch v41 -+ -+- Fixed inode times persistence problem -+=============================================================================== -+Changes for patch v42 -+ -+- Ported to kernel 2.1.108 (drivers/scsi/hosts.c hunk broke) -+=============================================================================== -+Changes for patch v43 -+ -+- Fixed spelling in debug -+ -+- Fixed bug in parsing "dilookup" -+ -+- More #ifdef's removed -+ -+- Supported Sparc keyboard (/dev/kbd) -+ -+- Supported DSP56001 digital signal processor (/dev/dsp56k) -+ -+- Supported Apple Desktop Bus (/dev/adb) -+ -+- Supported Coda network file system (/dev/cfs*) -+=============================================================================== -+Changes for patch v44 -+ -+- Fixed devfs inode leak when manually recreating inodes -+ -+- Fixed permission persistence problem when recreating inodes -+=============================================================================== -+Changes for patch v45 -+ -+- Ported to kernel 2.1.110 -+=============================================================================== -+Changes for patch v46 -+ -+- Ported to kernel 2.1.112-pre1 -+ -+- Removed harmless "unused variable" compiler warning -+ -+- Fixed modes for manually recreated device nodes -+=============================================================================== -+Changes for patch v47 -+ -+- Added NULL devfs inode warning in -+ -+- Force all inode nlink values to 1 -+=============================================================================== -+Changes for patch v48 -+ -+- Added "dimknod" option -+ -+- Set inode nlink to 0 when freeing dentries -+ -+- Added support for virtual console capture devices (/dev/vcs*) -+ Thanks to Dennis Hou -+ -+- Fixed modes for manually recreated symlinks -+=============================================================================== -+Changes for patch v49 -+ -+- Ported to kernel 2.1.113 -+=============================================================================== -+Changes for patch v50 -+ -+- Fixed bugs in recreated directories and symlinks -+=============================================================================== -+Changes for patch v51 -+ -+- Improved robustness of rc.devfs script -+ Thanks to Roderich Schupp -+ -+- Fixed bugs in recreated device nodes -+ -+- Fixed bug in currently unused -+ -+- Defined new type -+ -+- Improved debugging when getting entries -+ -+- Fixed bug where directories could be emptied -+ -+- Ported to kernel 2.1.115 -+=============================================================================== -+Changes for patch v52 -+ -+- Replaced dummy .epoch inode with .devfsd character device -+ -+- Modified rc.devfs to take account of above change -+ -+- Removed spurious driver warning messages when CONFIG_DEVFS_FS=n -+ -+- Implemented devfsd protocol revision 0 -+=============================================================================== -+Changes for patch v53 -+ -+- Ported to kernel 2.1.116 (kmod change broke hunk) -+ -+- Updated Documentation/Configure.help -+ -+- Test and tty pattern patch for rc.devfs script -+ Thanks to Roderich Schupp -+ -+- Added soothing message to warning in -+=============================================================================== -+Changes for patch v54 -+ -+- Ported to kernel 2.1.117 -+ -+- Fixed default permissions in sound driver -+ -+- Added support for frame buffer devices (/dev/fb*) -+=============================================================================== -+Changes for patch v55 -+ -+- Ported to kernel 2.1.119 -+ -+- Use GCC extensions for structure initialisations -+ -+- Implemented async open notification -+ -+- Incremented devfsd protocol revision to 1 -+=============================================================================== -+Changes for patch v56 -+ -+- Ported to kernel 2.1.120-pre3 -+ -+- Moved async open notification to end of -+=============================================================================== -+Changes for patch v57 -+ -+- Ported to kernel 2.1.121 -+ -+- Prepended "/dev/" to module load request -+ -+- Renamed to -+ -+- Created sample modules.conf file -+=============================================================================== -+Changes for patch v58 -+ -+- Fixed typo "AYSNC" -> "ASYNC" -+=============================================================================== -+Changes for patch v59 -+ -+- Added open flag for files -+=============================================================================== -+Changes for patch v60 -+ -+- Ported to kernel 2.1.123-pre2 -+=============================================================================== -+Changes for patch v61 -+ -+- Set i_blocks=0 and i_blksize=1024 in -+=============================================================================== -+Changes for patch v62 -+ -+- Ported to kernel 2.1.123 -+=============================================================================== -+Changes for patch v63 -+ -+- Ported to kernel 2.1.124-pre2 -+=============================================================================== -+Changes for patch v64 -+ -+- Fixed Unix98 pty support -+ -+- Increased buffer size in to avoid crash and -+ burn -+=============================================================================== -+Changes for patch v65 -+ -+- More Unix98 pty support fixes -+ -+- Added test for empty <> in -+ -+- Renamed to and published -+ -+- Created /dev/root symlink -+ Thanks to Roderich Schupp -+ with further modifications by me -+=============================================================================== -+Changes for patch v66 -+ -+- Yet more Unix98 pty support fixes (now tested) -+ -+- Created -+ -+- Support media change checks when CONFIG_DEVFS_ONLY=y -+ -+- Abolished Unix98-style PTY names for old PTY devices -+=============================================================================== -+Changes for patch v67 -+ -+- Added inline declaration for dummy -+ -+- Removed spurious "unable to register... in devfs" messages when -+ CONFIG_DEVFS_FS=n -+ -+- Fixed misc. devices when CONFIG_DEVFS_FS=n -+ -+- Limit auto-device numbering to majors 144 to 239 -+=============================================================================== -+Changes for patch v68 -+ -+- Hide unopened virtual consoles from directory listings -+ -+- Added support for video capture devices -+ -+- Ported to kernel 2.1.125 -+=============================================================================== -+Changes for patch v69 -+ -+- Fix for CONFIG_VT=n -+=============================================================================== -+Changes for patch v70 -+ -+- Added support for non-OSS/Free sound cards -+=============================================================================== -+Changes for patch v71 -+ -+- Ported to kernel 2.1.126-pre2 -+=============================================================================== -+Changes for patch v72 -+ -+- #ifdef's for CONFIG_DEVFS_DISABLE_OLD_NAMES removed -+=============================================================================== -+Changes for patch v73 -+ -+- CONFIG_DEVFS_DISABLE_OLD_NAMES replaced with "nocompat" boot option -+ -+- CONFIG_DEVFS_BOOT_OPTIONS removed: boot options always available -+=============================================================================== -+Changes for patch v74 -+ -+- Removed CONFIG_DEVFS_MOUNT and "mount" boot option and replaced with -+ "nomount" boot option -+ -+- Documentation updates -+ -+- Updated sample modules.conf -+=============================================================================== -+Changes for patch v75 -+ -+- Updated sample modules.conf -+ -+- Remount devfs after initrd finishes -+ -+- Ported to kernel 2.1.127 -+ -+- Added support for ISDN -+ Thanks to Christophe Leroy -+=============================================================================== -+Changes for patch v76 -+ -+- Updated an email address in ChangeLog -+ -+- CONFIG_DEVFS_ONLY replaced with "only" boot option -+=============================================================================== -+Changes for patch v77 -+ -+- Added DEVFS_FL_REMOVABLE flag -+ -+- Check for disc change when listing directories with removable media -+ devices -+ -+- Use DEVFS_FL_REMOVABLE in sd.c -+ -+- Ported to kernel 2.1.128 -+=============================================================================== -+Changes for patch v78 -+ -+- Only call on first call to -+ -+- Ported to kernel 2.1.129-pre5 -+ -+- ISDN support improvements -+ Thanks to Christophe Leroy -+=============================================================================== -+Changes for patch v79 -+ -+- Ported to kernel 2.1.130 -+ -+- Renamed miscdevice "apm" to "apm_bios" to be consistent with -+ devices.txt -+=============================================================================== -+Changes for patch v80 -+ -+- Ported to kernel 2.1.131 -+ -+- Updated for VFS change in 2.1.131 -+=============================================================================== -+Changes for patch v81 -+ -+- Fixed permissions on /dev/ptmx -+=============================================================================== -+Changes for patch v82 -+ -+- Ported to kernel 2.1.132-pre4 -+ -+- Changed initial permissions on /dev/pts/* -+ -+- Created -+ -+- Added "symlinks" boot option -+ -+- Changed devfs_register_blkdev() back to register_blkdev() for IDE -+ -+- Check for partitions on removable media in -+=============================================================================== -+Changes for patch v83 -+ -+- Fixed support for ramdisc when using string-based root FS name -+ -+- Ported to kernel 2.2.0-pre1 -+=============================================================================== -+Changes for patch v84 -+ -+- Ported to kernel 2.2.0-pre7 -+=============================================================================== -+Changes for patch v85 -+ -+- Compile fixes for driver/sound/sound_common.c (non-module) and -+ drivers/isdn/isdn_common.c -+ Thanks to Christophe Leroy -+ -+- Added support for registering regular files -+ -+- Created -+ -+- Added /dev/cpu/mtrr as an alternative interface to /proc/mtrr -+ -+- Update devfs inodes from entries if not changed through FS -+=============================================================================== -+Changes for patch v86 -+ -+- Ported to kernel 2.2.0-pre9 -+=============================================================================== -+Changes for patch v87 -+ -+- Fixed bug when mounting non-devfs devices in a devfs -+=============================================================================== -+Changes for patch v88 -+ -+- Fixed to only initialise temporary inodes -+ -+- Trap for NULL fops in -+ -+- Return -ENODEV in for non-driver inodes -+ -+- Fixed bug when unswapping non-devfs devices in a devfs -+=============================================================================== -+Changes for patch v89 -+ -+- Switched to C data types in include/linux/devfs_fs.h -+ -+- Switched from PATH_MAX to DEVFS_PATHLEN -+ -+- Updated Documentation/filesystems/devfs/modules.conf to take account -+ of reverse scanning (!) by modprobe -+ -+- Ported to kernel 2.2.0 -+=============================================================================== -+Changes for patch v90 -+ -+- CONFIG_DEVFS_DISABLE_OLD_TTY_NAMES replaced with "nottycompat" boot -+ option -+ -+- CONFIG_DEVFS_TTY_COMPAT removed: existing "symlinks" boot option now -+ controls this. This means you must have libc 5.4.44 or later, or a -+ recent version of libc 6 if you use the "symlinks" option -+=============================================================================== -+Changes for patch v91 -+ -+- Switch from to in -+ drivers/char/vc_screen.c to fix problems with Midnight Commander -+=============================================================================== -+Changes for patch v92 -+ -+- Ported to kernel 2.2.2-pre5 -+=============================================================================== -+Changes for patch v93 -+ -+- Modified in drivers/scsi/sd.c to cope with devices that -+ don't exist (which happens with new RAID autostart code printk()s) -+=============================================================================== -+Changes for patch v94 -+ -+- Fixed bug in joystick driver: only first joystick was registered -+=============================================================================== -+Changes for patch v95 -+ -+- Fixed another bug in joystick driver -+ -+- Fixed to not overrun event buffer -+=============================================================================== -+Changes for patch v96 -+ -+- Ported to kernel 2.2.5-2 -+ -+- Created -+ -+- Fixed bugs: compatibility entries were not unregistered for: -+ loop driver -+ floppy driver -+ RAMDISC driver -+ IDE tape driver -+ SCSI CD-ROM driver -+ SCSI HDD driver -+=============================================================================== -+Changes for patch v97 -+ -+- Fixed bugs: compatibility entries were not unregistered for: -+ ALSA sound driver -+ partitions in generic disc driver -+ -+- Don't return unregistred entries in -+ -+- Panic in if entry unregistered -+ -+- Don't panic in for duplicates -+=============================================================================== -+Changes for patch v98 -+ -+- Don't unregister already unregistered entries in -+ -+- Register entry in -+ -+- Unregister entry in -+ -+- Changed to in drivers/char/tty_io.c -+ -+- Ported to kernel 2.2.7 -+=============================================================================== -+Changes for patch v99 -+ -+- Ported to kernel 2.2.8 -+ -+- Fixed bug in drivers/scsi/sd.c when >16 SCSI discs -+ -+- Disable warning messages when unable to read partition table for -+ removable media -+=============================================================================== -+Changes for patch v100 -+ -+- Ported to kernel 2.3.1-pre5 -+ -+- Added "oops-on-panic" boot option -+ -+- Improved debugging in and -+ -+- Register entry in -+ -+- Unregister entry in -+ -+- Register entry in -+ -+- Unregister entry in -+ -+- Added support for ALSA drivers -+=============================================================================== -+Changes for patch v101 -+ -+- Ported to kernel 2.3.2 -+=============================================================================== -+Changes for patch v102 -+ -+- Update serial driver to register PCMCIA entries -+ Thanks to Roch-Alexandre Nomine-Beguin -+ -+- Updated an email address in ChangeLog -+ -+- Hide virtual console capture entries from directory listings when -+ corresponding console device is not open -+=============================================================================== -+Changes for patch v103 -+ -+- Ported to kernel 2.3.3 -+=============================================================================== -+Changes for patch v104 -+ -+- Added documentation for some functions -+ -+- Added "doc" target to fs/devfs/Makefile -+ -+- Added "v4l" directory for video4linux devices -+ -+- Replaced call to in with call to -+ -+ -+- Moved registration for sr and sg drivers from detect() to attach() -+ methods -+ -+- Register entries in and unregister in -+ -+- Work around IDE driver treating CD-ROM as gendisk -+ -+- Use instead of in rc.devfs -+ -+- Updated ToDo list -+ -+- Removed "oops-on-panic" boot option: now always Oops -+=============================================================================== -+Changes for patch v105 -+ -+- Unregister SCSI host from in -+ Thanks to Zoltán Böszörményi -+ -+- Don't save /dev/log in rc.devfs -+ -+- Ported to kernel 2.3.4-pre1 -+=============================================================================== -+Changes for patch v106 -+ -+- Fixed silly typo in drivers/scsi/st.c -+ -+- Improved debugging in -+=============================================================================== -+Changes for patch v107 -+ -+- Added "diunlink" and "nokmod" boot options -+ -+- Removed superfluous warning message in -+=============================================================================== -+Changes for patch v108 -+ -+- Remove entries when unloading sound module -+=============================================================================== -+Changes for patch v109 -+ -+- Ported to kernel 2.3.6-pre2 -+=============================================================================== -+Changes for patch v110 -+ -+- Took account of change to -+=============================================================================== -+Changes for patch v111 -+ -+- Created separate event queue for each mounted devfs -+ -+- Removed -+ -+- Created new ioctl()s for devfsd -+ -+- Incremented devfsd protocol revision to 3 -+ -+- Fixed bug when re-creating directories: contents were lost -+ -+- Block access to inodes until devfsd updates permissions -+=============================================================================== -+Changes for patch v112 -+ -+- Modified patch so it applies against 2.3.5 and 2.3.6 -+ -+- Updated an email address in ChangeLog -+ -+- Do not automatically change ownership/protection of /dev/tty -+ -+- Updated sample modules.conf -+ -+- Switched to sending process uid/gid to devfsd -+ -+- Renamed to -+ -+- Added DEVFSD_NOTIFY_LOOKUP event -+ -+- Added DEVFSD_NOTIFY_CHANGE event -+ -+- Added DEVFSD_NOTIFY_CREATE event -+ -+- Incremented devfsd protocol revision to 4 -+ -+- Moved kernel-specific stuff to include/linux/devfs_fs_kernel.h -+=============================================================================== -+Changes for patch v113 -+ -+- Ported to kernel 2.3.9 -+ -+- Restricted permissions on some block devices -+=============================================================================== -+Changes for patch v114 -+ -+- Added support for /dev/netlink -+ Thanks to Dennis Hou -+ -+- Return EISDIR rather than EINVAL for read(2) on directories -+ -+- Ported to kernel 2.3.10 -+=============================================================================== -+Changes for patch v115 -+ -+- Added support for all remaining character devices -+ Thanks to Dennis Hou -+ -+- Cleaned up netlink support -+=============================================================================== -+Changes for patch v116 -+ -+- Added support for /dev/parport%d -+ Thanks to Tim Waugh -+ -+- Fixed parallel port ATAPI tape driver -+ -+- Fixed Atari SLM laser printer driver -+=============================================================================== -+Changes for patch v117 -+ -+- Added support for COSA card -+ Thanks to Dennis Hou -+ -+- Fixed drivers/char/ppdev.c: missing #include -+ -+- Fixed drivers/char/ftape/zftape/zftape-init.c -+ Thanks to Vladimir Popov -+=============================================================================== -+Changes for patch v118 -+ -+- Ported to kernel 2.3.15-pre3 -+ -+- Fixed bug in loop driver -+ -+- Unregister /dev/lp%d entries in drivers/char/lp.c -+ Thanks to Maciej W. Rozycki -+=============================================================================== -+Changes for patch v119 -+ -+- Ported to kernel 2.3.16 -+=============================================================================== -+Changes for patch v120 -+ -+- Fixed bug in drivers/scsi/scsi.c -+ -+- Added /dev/ppp -+ Thanks to Dennis Hou -+ -+- Ported to kernel 2.3.17 -+=============================================================================== -+Changes for patch v121 -+ -+- Fixed bug in drivers/block/loop.c -+ -+- Ported to kernel 2.3.18 -+=============================================================================== -+Changes for patch v122 -+ -+- Ported to kernel 2.3.19 -+=============================================================================== -+Changes for patch v123 -+ -+- Ported to kernel 2.3.20 -+=============================================================================== -+Changes for patch v124 -+ -+- Ported to kernel 2.3.21 -+=============================================================================== -+Changes for patch v125 -+ -+- Created , , -+ and -+ Added <> parameter to , , -+ and -+ Work sponsored by SGI -+ -+- Fixed apparent bug in COSA driver -+ -+- Re-instated "scsihosts=" boot option -+=============================================================================== -+Changes for patch v126 -+ -+- Always create /dev/pts if CONFIG_UNIX98_PTYS=y -+ -+- Fixed call to in drivers/block/ide-disk.c -+ Thanks to Dennis Hou -+ -+- Allow multiple unregistrations -+ -+- Created /dev/scsi hierarchy -+ Work sponsored by SGI -+=============================================================================== -+Changes for patch v127 -+ -+Work sponsored by SGI -+ -+- No longer disable devpts if devfs enabled (caveat emptor) -+ -+- Added flags array to struct gendisk and removed code from -+ drivers/scsi/sd.c -+ -+- Created /dev/discs hierarchy -+=============================================================================== -+Changes for patch v128 -+ -+Work sponsored by SGI -+ -+- Created /dev/cdroms hierarchy -+=============================================================================== -+Changes for patch v129 -+ -+Work sponsored by SGI -+ -+- Removed compatibility entries for sound devices -+ -+- Removed compatibility entries for printer devices -+ -+- Removed compatibility entries for video4linux devices -+ -+- Removed compatibility entries for parallel port devices -+ -+- Removed compatibility entries for frame buffer devices -+=============================================================================== -+Changes for patch v130 -+ -+Work sponsored by SGI -+ -+- Added major and minor number to devfsd protocol -+ -+- Incremented devfsd protocol revision to 5 -+ -+- Removed compatibility entries for SoundBlaster CD-ROMs -+ -+- Removed compatibility entries for netlink devices -+ -+- Removed compatibility entries for SCSI generic devices -+ -+- Removed compatibility entries for SCSI tape devices -+=============================================================================== -+Changes for patch v131 -+ -+Work sponsored by SGI -+ -+- Support info pointer for all devfs entry types -+ -+- Added <> parameter to and -+ -+- Removed /dev/st hierarchy -+ -+- Removed /dev/sg hierarchy -+ -+- Removed compatibility entries for loop devices -+ -+- Removed compatibility entries for IDE tape devices -+ -+- Removed compatibility entries for SCSI CD-ROMs -+ -+- Removed /dev/sr hierarchy -+=============================================================================== -+Changes for patch v132 -+ -+Work sponsored by SGI -+ -+- Removed compatibility entries for floppy devices -+ -+- Removed compatibility entries for RAMDISCs -+ -+- Removed compatibility entries for meta-devices -+ -+- Removed compatibility entries for SCSI discs -+ -+- Created -+ -+- Removed /dev/sd hierarchy -+ -+- Support "../" when searching devfs namespace -+ -+- Created /dev/ide/host* hierarchy -+ -+- Supported IDE hard discs in /dev/ide/host* hierarchy -+ -+- Removed compatibility entries for IDE discs -+ -+- Removed /dev/ide/hd hierarchy -+ -+- Supported IDE CD-ROMs in /dev/ide/host* hierarchy -+ -+- Removed compatibility entries for IDE CD-ROMs -+ -+- Removed /dev/ide/cd hierarchy -+=============================================================================== -+Changes for patch v133 -+ -+Work sponsored by SGI -+ -+- Created -+ -+- Fixed bug in fs/partitions/check.c when rescanning -+=============================================================================== -+Changes for patch v134 -+ -+Work sponsored by SGI -+ -+- Removed /dev/sd, /dev/sr, /dev/st and /dev/sg directories -+ -+- Removed /dev/ide/hd directory -+ -+- Exported -+ -+- Created and /dev/tapes hierarchy -+ -+- Removed /dev/ide/mt hierarchy -+ -+- Removed /dev/ide/fd hierarchy -+ -+- Ported to kernel 2.3.25 -+=============================================================================== -+Changes for patch v135 -+ -+Work sponsored by SGI -+ -+- Removed compatibility entries for virtual console capture devices -+ -+- Removed unused -+ -+- Removed compatibility entries for serial devices -+ -+- Removed compatibility entries for console devices -+ -+- Do not hide entries from devfsd or children -+ -+- Removed DEVFS_FL_TTY_COMPAT flag -+ -+- Removed "nottycompat" boot option -+ -+- Removed -+=============================================================================== -+Changes for patch v136 -+ -+Work sponsored by SGI -+ -+- Moved BSD pty devices to /dev/pty -+ -+- Added DEVFS_FL_WAIT flag -+=============================================================================== -+Changes for patch v137 -+ -+Work sponsored by SGI -+ -+- Really fixed bug in fs/partitions/check.c when rescanning -+ -+- Support new "disc" naming scheme in -+ -+- Allow NULL fops in -+ -+- Removed redundant name functions in SCSI disc and IDE drivers -+=============================================================================== -+Changes for patch v138 -+ -+Work sponsored by SGI -+ -+- Fixed old bugs in drivers/block/paride/pt.c, drivers/char/tpqic02.c, -+ drivers/net/wan/cosa.c and drivers/scsi/scsi.c -+ Thanks to Sergey Kubushin -+ -+- Fall back to major table if NULL fops given to -+=============================================================================== -+Changes for patch v139 -+ -+Work sponsored by SGI -+ -+- Corrected and moved and declarations -+ from arch/alpha/kernel/osf_sys.c to include/linux/fs.h -+ -+- Removed name function from struct gendisk -+ -+- Updated devfs FAQ -+=============================================================================== -+Changes for patch v140 -+ -+Work sponsored by SGI -+ -+- Ported to kernel 2.3.27 -+=============================================================================== -+Changes for patch v141 -+ -+Work sponsored by SGI -+ -+- Bug fix in arch/m68k/atari/joystick.c -+ -+- Moved ISDN and capi devices to /dev/isdn -+=============================================================================== -+Changes for patch v142 -+ -+Work sponsored by SGI -+ -+- Bug fix in drivers/block/ide-probe.c (patch confusion) -+=============================================================================== -+Changes for patch v143 -+ -+Work sponsored by SGI -+ -+- Bug fix in drivers/block/blkpg.c:partition_name() -+=============================================================================== -+Changes for patch v144 -+ -+Work sponsored by SGI -+ -+- Ported to kernel 2.3.29 -+ -+- Removed calls to from cdu31a, cm206, mcd and mcdx -+ CD-ROM drivers: generic driver handles this now -+ -+- Moved joystick devices to /dev/joysticks -+=============================================================================== -+Changes for patch v145 -+ -+Work sponsored by SGI -+ -+- Ported to kernel 2.3.30-pre3 -+ -+- Register whole-disc entry even for invalid partition tables -+ -+- Fixed bug in mounting root FS when initrd enabled -+ -+- Fixed device entry leak with IDE CD-ROMs -+ -+- Fixed compile problem with drivers/isdn/isdn_common.c -+ -+- Moved COSA devices to /dev/cosa -+ -+- Support fifos when unregistering -+ -+- Created and used in many drivers -+ -+- Moved Coda devices to /dev/coda -+ -+- Moved parallel port IDE tapes to /dev/pt -+ -+- Moved parallel port IDE generic devices to /dev/pg -+=============================================================================== -+Changes for patch v146 -+ -+Work sponsored by SGI -+ -+- Removed obsolete DEVFS_FL_COMPAT and DEVFS_FL_TOLERANT flags -+ -+- Fixed compile problem with fs/coda/psdev.c -+ -+- Reinstate change to in -+ drivers/block/ide-probe.c now that fs/isofs/inode.c is fixed -+ -+- Switched to in drivers/block/floppy.c, -+ drivers/scsi/sr.c and drivers/block/md.c -+ -+- Moved DAC960 devices to /dev/dac960 -+=============================================================================== -+Changes for patch v147 -+ -+Work sponsored by SGI -+ -+- Ported to kernel 2.3.32-pre4 -+=============================================================================== -+Changes for patch v148 -+ -+Work sponsored by SGI -+ -+- Removed kmod support: use devfsd instead -+ -+- Moved miscellaneous character devices to /dev/misc -+=============================================================================== -+Changes for patch v149 -+ -+Work sponsored by SGI -+ -+- Ensure include/linux/joystick.h is OK for user-space -+ -+- Improved debugging in -+ -+- Ensure dentries created by devfsd will be cleaned up -+=============================================================================== -+Changes for patch v150 -+ -+Work sponsored by SGI -+ -+- Ported to kernel 2.3.34 -+=============================================================================== -+Changes for patch v151 -+ -+Work sponsored by SGI -+ -+- Ported to kernel 2.3.35-pre1 -+ -+- Created -+=============================================================================== -+Changes for patch v152 -+ -+Work sponsored by SGI -+ -+- Updated sample modules.conf -+ -+- Ported to kernel 2.3.36-pre1 -+=============================================================================== -+Changes for patch v153 -+ -+Work sponsored by SGI -+ -+- Ported to kernel 2.3.42 -+ -+- Removed -+=============================================================================== -+Changes for patch v154 -+ -+Work sponsored by SGI -+ -+- Took account of device number changes for /dev/fb* -+=============================================================================== -+Changes for patch v155 -+ -+Work sponsored by SGI -+ -+- Ported to kernel 2.3.43-pre8 -+ -+- Moved /dev/tty0 to /dev/vc/0 -+ -+- Moved sequence number formatting from <_tty_make_name> to drivers -+=============================================================================== -+Changes for patch v156 -+ -+Work sponsored by SGI -+ -+- Fixed breakage in drivers/scsi/sd.c due to recent SCSI changes -+=============================================================================== -+Changes for patch v157 -+ -+Work sponsored by SGI -+ -+- Ported to kernel 2.3.45 -+=============================================================================== -+Changes for patch v158 -+ -+Work sponsored by SGI -+ -+- Ported to kernel 2.3.46-pre2 -+=============================================================================== -+Changes for patch v159 -+ -+Work sponsored by SGI -+ -+- Fixed drivers/block/md.c -+ Thanks to Mike Galbraith -+ -+- Documentation fixes -+ -+- Moved device registration from to -+ Thanks to Tim Waugh -+=============================================================================== -+Changes for patch v160 -+ -+Work sponsored by SGI -+ -+- Fixed drivers/char/joystick/joystick.c -+ Thanks to Vojtech Pavlik -+ -+- Documentation updates -+ -+- Fixed arch/i386/kernel/mtrr.c if procfs and devfs not enabled -+ -+- Fixed drivers/char/stallion.c -+=============================================================================== -+Changes for patch v161 -+ -+Work sponsored by SGI -+ -+- Remove /dev/ide when ide-mod is unloaded -+ -+- Fixed bug in drivers/block/ide-probe.c when secondary but no primary -+ -+- Added DEVFS_FL_NO_PERSISTENCE flag -+ -+- Used new DEVFS_FL_NO_PERSISTENCE flag for Unix98 pty slaves -+ -+- Removed unnecessary call to in -+ -+ -+- Only set auto-ownership for /dev/pty/s* -+=============================================================================== -+Changes for patch v162 -+ -+Work sponsored by SGI -+ -+- Set inode->i_size to correct size for symlinks -+ Thanks to Jeremy Fitzhardinge -+ -+- Only give lookup() method to directories to comply with new VFS -+ assumptions -+ -+- Remove unnecessary tests in symlink methods -+ -+- Don't kill existing block ops in -+ -+- Restore auto-ownership for /dev/pty/m* -+=============================================================================== -+Changes for patch v163 -+ -+Work sponsored by SGI -+ -+- Don't create missing directories in -+ -+- Removed Documentation/filesystems/devfs/mk-devlinks -+ -+- Updated Documentation/filesystems/devfs/README -+=============================================================================== -+Changes for patch v164 -+ -+Work sponsored by SGI -+ -+- Fixed CONFIG_DEVFS breakage in drivers/char/serial.c introduced in -+ linux-2.3.99-pre6-7 -+=============================================================================== -+Changes for patch v165 -+ -+Work sponsored by SGI -+ -+- Ported to kernel 2.3.99-pre6 -+=============================================================================== -+Changes for patch v166 -+ -+Work sponsored by SGI -+ -+- Added CONFIG_DEVFS_MOUNT -+=============================================================================== -+Changes for patch v167 -+ -+Work sponsored by SGI -+ -+- Updated Documentation/filesystems/devfs/README -+ -+- Updated sample modules.conf -+=============================================================================== -+Changes for patch v168 -+ -+Work sponsored by SGI -+ -+- Disabled multi-mount capability (use VFS bindings instead) -+ -+- Updated README from master HTML file -+=============================================================================== -+Changes for patch v169 -+ -+Work sponsored by SGI -+ -+- Removed multi-mount code -+ -+- Removed compatibility macros: VFS has changed too much -+=============================================================================== -+Changes for patch v170 -+ -+Work sponsored by SGI -+ -+- Updated README from master HTML file -+ -+- Merged devfs inode into devfs entry -+=============================================================================== -+Changes for patch v171 -+ -+Work sponsored by SGI -+ -+- Updated sample modules.conf -+ -+- Removed dead code in which used to call -+ -+ -+- Ported to kernel 2.4.0-test2-pre3 -+=============================================================================== -+Changes for patch v172 -+ -+Work sponsored by SGI -+ -+- Changed interface to -+ -+- Changed interface to -+=============================================================================== -+Changes for patch v173 -+ -+Work sponsored by SGI -+ -+- Simplified interface to -+ -+- Simplified interface to -+ -+- Simplified interface to -+=============================================================================== -+Changes for patch v174 -+ -+Work sponsored by SGI -+ -+- Updated README from master HTML file -+=============================================================================== -+Changes for patch v175 -+ -+Work sponsored by SGI -+ -+- DocBook update for fs/devfs/base.c -+ Thanks to Tim Waugh -+ -+- Removed stale fs/tunnel.c (was never used or completed) -+=============================================================================== -+Changes for patch v176 -+ -+Work sponsored by SGI -+ -+- Updated ToDo list -+ -+- Removed sample modules.conf: now distributed with devfsd -+ -+- Updated README from master HTML file -+ -+- Ported to kernel 2.4.0-test3-pre4 (which had devfs-patch-v174) -+=============================================================================== -+Changes for patch v177 -+ -+- Updated README from master HTML file -+ -+- Documentation cleanups -+ -+- Ensure terminates string for root entry -+ Thanks to Tim Jansen -+ -+- Exported to modules -+ -+- Make send events to devfsd -+ -+- Cleaned up option processing in -+ -+- Fixed bugs in handling symlinks: could leak or cause Oops -+ -+- Cleaned up directory handling by separating fops -+ Thanks to Alexander Viro -+=============================================================================== -+Changes for patch v178 -+ -+- Fixed handling of inverted options in -+=============================================================================== -+Changes for patch v179 -+ -+- Adjusted to account for fix -+=============================================================================== -+Changes for patch v180 -+ -+- Fixed !CONFIG_DEVFS_FS stub declaration of -+=============================================================================== -+Changes for patch v181 -+ -+- Answered question posed by Al Viro and removed his comments from -+ -+- Moved setting of registered flag after other fields are changed -+ -+- Fixed race between and -+ -+- Global VFS changes added bogus BKL to devfsd_close(): removed -+ -+- Widened locking in and -+ -+- Replaced stack usage with kmalloc -+ -+- Simplified locking in and fixed memory leak -+=============================================================================== -+Changes for patch v182 -+ -+- Created and -+ -+- Removed broken devnum allocation and use -+ -+- Fixed old devnum leak by calling new -+ -+- Created -+ -+- Fixed number leak for /dev/cdroms/cdrom%d -+ -+- Fixed number leak for /dev/discs/disc%d -+=============================================================================== -+Changes for patch v183 -+ -+- Fixed bug in which could hang boot process -+=============================================================================== -+Changes for patch v184 -+ -+- Documentation typo fix for fs/devfs/util.c -+ -+- Fixed drivers/char/stallion.c for devfs -+ -+- Added DEVFSD_NOTIFY_DELETE event -+ -+- Updated README from master HTML file -+ -+- Removed #include from fs/devfs/base.c -+=============================================================================== -+Changes for patch v185 -+ -+- Made and in fs/devfs/util.c -+ private -+ -+- Fixed inode table races by removing it and using inode->u.generic_ip -+ instead -+ -+- Moved into -+ -+- Moved into -+=============================================================================== -+Changes for patch v186 -+ -+- Fixed race in for uni-processor -+ -+- Updated README from master HTML file -+=============================================================================== -+Changes for patch v187 -+ -+- Fixed drivers/char/stallion.c for devfs -+ -+- Fixed drivers/char/rocket.c for devfs -+ -+- Fixed bug in : limited to 128 numbers -+=============================================================================== -+Changes for patch v188 -+ -+- Updated major masks in fs/devfs/util.c up to Linus' "no new majors" -+ proclamation. Block: were 126 now 122 free, char: were 26 now 19 free -+ -+- Updated README from master HTML file -+ -+- Removed remnant of multi-mount support in -+ -+- Removed unused DEVFS_FL_SHOW_UNREG flag -+=============================================================================== -+Changes for patch v189 -+ -+- Removed nlink field from struct devfs_inode -+ -+- Removed auto-ownership for /dev/pty/* (BSD ptys) and used -+ DEVFS_FL_CURRENT_OWNER|DEVFS_FL_NO_PERSISTENCE for /dev/pty/s* (just -+ like Unix98 pty slaves) and made /dev/pty/m* rw-rw-rw- access -+=============================================================================== -+Changes for patch v190 -+ -+- Updated README from master HTML file -+ -+- Replaced BKL with global rwsem to protect symlink data (quick and -+ dirty hack) -+=============================================================================== -+Changes for patch v191 -+ -+- Replaced global rwsem for symlink with per-link refcount -+=============================================================================== -+Changes for patch v192 -+ -+- Removed unnecessary #ifdef CONFIG_DEVFS_FS from arch/i386/kernel/mtrr.c -+ -+- Ported to kernel 2.4.10-pre11 -+ -+- Set inode->i_mapping->a_ops for block nodes in -+=============================================================================== -+Changes for patch v193 -+ -+- Went back to global rwsem for symlinks (refcount scheme no good) -+=============================================================================== -+Changes for patch v194 -+ -+- Fixed overrun in by removing function (not needed) -+ -+- Updated README from master HTML file -+=============================================================================== -+Changes for patch v195 -+ -+- Fixed buffer underrun in -+ -+- Moved down_read() from to -+=============================================================================== -+Changes for patch v196 -+ -+- Fixed race in when setting event mask -+ Thanks to Kari Hurtta -+ -+- Avoid deadlock in by using temporary buffer -+=============================================================================== -+Changes for patch v197 -+ -+- First release of new locking code for devfs core (v1.0) -+ -+- Fixed bug in drivers/cdrom/cdrom.c -+=============================================================================== -+Changes for patch v198 -+ -+- Discard temporary buffer, now use "%s" for dentry names -+ -+- Don't generate path in : use fake entry instead -+ -+- Use "existing" directory in <_devfs_make_parent_for_leaf> -+ -+- Use slab cache rather than fixed buffer for devfsd events -+=============================================================================== -+Changes for patch v199 -+ -+- Removed obsolete usage of DEVFS_FL_NO_PERSISTENCE -+ -+- Send DEVFSD_NOTIFY_REGISTERED events in -+ -+- Fixed locking bug in due to typo -+ -+- Do not send CREATE, CHANGE, ASYNC_OPEN or DELETE events from devfsd -+ or children -+=============================================================================== -+Changes for patch v200 -+ -+- Ported to kernel 2.5.1-pre2 -+=============================================================================== -+Changes for patch v201 -+ -+- Fixed bug in : was dereferencing freed pointer -+=============================================================================== -+Changes for patch v202 -+ -+- Fixed bug in : was dereferencing freed pointer -+ -+- Added process group check for devfsd privileges -+=============================================================================== -+Changes for patch v203 -+ -+- Use SLAB_ATOMIC in from -+=============================================================================== -+Changes for patch v204 -+ -+- Removed long obsolete rc.devfs -+ -+- Return old entry in for 2.4.x kernels -+ -+- Updated README from master HTML file -+ -+- Increment refcount on module in -+ -+- Created and exported -+ -+- Increment refcount on module in -+ -+- Created and used where needed to fix races -+ -+- Added clarifying comments in response to preliminary EMC code review -+ -+- Added poisoning to -+ -+- Improved debugging messages -+ -+- Fixed unregister bugs in drivers/md/lvm-fs.c -+=============================================================================== -+Changes for patch v205 -+ -+- Corrected (made useful) debugging message in -+ -+- Moved in to -+ -+- Fixed drivers/md/lvm-fs.c to create "lvm" entry -+ -+- Added magic number to guard against scribbling drivers -+ -+- Only return old entry in if a directory -+ -+- Defined macros for error and debug messages -+ -+- Updated README from master HTML file -+=============================================================================== -+Changes for patch v206 -+ -+- Added support for multiple Compaq cpqarray controllers -+ -+- Fixed (rare, old) race in -+=============================================================================== -+Changes for patch v207 -+ -+- Fixed deadlock bug in -+ -+- Tag VFS deletable in if handle ignored -+ -+- Updated README from master HTML file -+=============================================================================== -+Changes for patch v208 -+ -+- Added KERN_* to remaining messages -+ -+- Cleaned up declaration of -+ -+- Updated README from master HTML file -+=============================================================================== -+Changes for patch v209 -+ -+- Updated README from master HTML file -+ -+- Removed silently introduced calls to lock_kernel() and -+ unlock_kernel() due to recent VFS locking changes. BKL isn't -+ required in devfs -+ -+- Changed to allow later additions if not yet empty -+ -+- Added calls to in drivers/block/blkpc.c -+ and -+ -+- Fixed bug in : was clearing beyond -+ bitfield -+ -+- Fixed bitfield data type for -+ -+- Made major bitfield type and initialiser 64 bit safe -+=============================================================================== -+Changes for patch v210 -+ -+- Updated fs/devfs/util.c to fix shift warning on 64 bit machines -+ Thanks to Anton Blanchard -+ -+- Updated README from master HTML file -+=============================================================================== -+Changes for patch v211 -+ -+- Do not put miscellaneous character devices in /dev/misc if they -+ specify their own directory (i.e. contain a '/' character) -+ -+- Copied macro for error messages from fs/devfs/base.c to -+ fs/devfs/util.c and made use of this macro -+ -+- Removed 2.4.x compatibility code from fs/devfs/base.c -+=============================================================================== -+Changes for patch v212 -+ -+- Added BKL to because drivers still need it -+=============================================================================== -+Changes for patch v213 -+ -+- Protected and -+ from changing directory contents -+=============================================================================== -+Changes for patch v214 -+ -+- Switched to ISO C structure field initialisers -+ -+- Switch to set_current_state() and move before add_wait_queue() -+ -+- Updated README from master HTML file -+ -+- Fixed devfs entry leak in when *readdir fails -+=============================================================================== -+Changes for patch v215 -+ -+- Created -+ -+- Switched many functions from to -+ -+ -+- Switched many functions from to -+=============================================================================== -+Changes for patch v216 -+ -+- Switched arch/ia64/sn/io/hcl.c from to -+ -+ -+- Removed deprecated -+=============================================================================== -+Changes for patch v217 -+ -+- Exported and to modules -+ -+- Updated README from master HTML file -+ -+- Fixed module unload race in -+=============================================================================== -+Changes for patch v218 -+ -+- Removed DEVFS_FL_AUTO_OWNER flag -+ -+- Switched lingering structure field initialiser to ISO C -+ -+- Added locking when setting/clearing flags -+ -+- Documentation fix in fs/devfs/util.c -diff -urN linux-2.6.19.old/Documentation/filesystems/devfs/README linux-2.6.19.dev/Documentation/filesystems/devfs/README ---- linux-2.6.19.old/Documentation/filesystems/devfs/README 1970-01-01 01:00:00.000000000 +0100 -+++ linux-2.6.19.dev/Documentation/filesystems/devfs/README 2006-12-14 03:12:59.000000000 +0100 -@@ -0,0 +1,1959 @@ -+Devfs (Device File System) FAQ -+ -+ -+Linux Devfs (Device File System) FAQ -+Richard Gooch -+20-AUG-2002 -+ -+ -+Document languages: -+ -+ -+ -+ -+ -+ -+ -+----------------------------------------------------------------------------- -+ -+NOTE: the master copy of this document is available online at: -+ -+http://www.atnf.csiro.au/~rgooch/linux/docs/devfs.html -+and looks much better than the text version distributed with the -+kernel sources. A mirror site is available at: -+ -+http://www.ras.ucalgary.ca/~rgooch/linux/docs/devfs.html -+ -+There is also an optional daemon that may be used with devfs. You can -+find out more about it at: -+ -+http://www.atnf.csiro.au/~rgooch/linux/ -+ -+A mailing list is available which you may subscribe to. Send -+email -+to majordomo@oss.sgi.com with the following line in the -+body of the message: -+subscribe devfs -+To unsubscribe, send the message body: -+unsubscribe devfs -+instead. The list is archived at -+ -+http://oss.sgi.com/projects/devfs/archive/. -+ -+----------------------------------------------------------------------------- -+ -+Contents -+ -+ -+What is it? -+ -+Why do it? -+ -+Who else does it? -+ -+How it works -+ -+Operational issues (essential reading) -+ -+Instructions for the impatient -+Permissions persistence across reboots -+Dealing with drivers without devfs support -+All the way with Devfs -+Other Issues -+Kernel Naming Scheme -+Devfsd Naming Scheme -+Old Compatibility Names -+SCSI Host Probing Issues -+ -+ -+ -+Device drivers currently ported -+ -+Allocation of Device Numbers -+ -+Questions and Answers -+ -+Making things work -+Alternatives to devfs -+What I don't like about devfs -+How to report bugs -+Strange kernel messages -+Compilation problems with devfsd -+ -+ -+Other resources -+ -+Translations of this document -+ -+ -+----------------------------------------------------------------------------- -+ -+ -+What is it? -+ -+Devfs is an alternative to "real" character and block special devices -+on your root filesystem. Kernel device drivers can register devices by -+name rather than major and minor numbers. These devices will appear in -+devfs automatically, with whatever default ownership and -+protection the driver specified. A daemon (devfsd) can be used to -+override these defaults. Devfs has been in the kernel since 2.3.46. -+ -+NOTE that devfs is entirely optional. If you prefer the old -+disc-based device nodes, then simply leave CONFIG_DEVFS_FS=n (the -+default). In this case, nothing will change. ALSO NOTE that if you do -+enable devfs, the defaults are such that full compatibility is -+maintained with the old devices names. -+ -+There are two aspects to devfs: one is the underlying device -+namespace, which is a namespace just like any mounted filesystem. The -+other aspect is the filesystem code which provides a view of the -+device namespace. The reason I make a distinction is because devfs -+can be mounted many times, with each mount showing the same device -+namespace. Changes made are global to all mounted devfs filesystems. -+Also, because the devfs namespace exists without any devfs mounts, you -+can easily mount the root filesystem by referring to an entry in the -+devfs namespace. -+ -+ -+The cost of devfs is a small increase in kernel code size and memory -+usage. About 7 pages of code (some of that in __init sections) and 72 -+bytes for each entry in the namespace. A modest system has only a -+couple of hundred device entries, so this costs a few more -+pages. Compare this with the suggestion to put /dev on a ramdisc. -+ -+On a typical machine, the cost is under 0.2 percent. On a modest -+system with 64 MBytes of RAM, the cost is under 0.1 percent. The -+accusations of "bloatware" levelled at devfs are not justified. -+ -+----------------------------------------------------------------------------- -+ -+ -+Why do it? -+ -+There are several problems that devfs addresses. Some of these -+problems are more serious than others (depending on your point of -+view), and some can be solved without devfs. However, the totality of -+these problems really calls out for devfs. -+ -+The choice is a patchwork of inefficient user space solutions, which -+are complex and likely to be fragile, or to use a simple and efficient -+devfs which is robust. -+ -+There have been many counter-proposals to devfs, all seeking to -+provide some of the benefits without actually implementing devfs. So -+far there has been an absence of code and no proposed alternative has -+been able to provide all the features that devfs does. Further, -+alternative proposals require far more complexity in user-space (and -+still deliver less functionality than devfs). Some people have the -+mantra of reducing "kernel bloat", but don't consider the effects on -+user-space. -+ -+A good solution limits the total complexity of kernel-space and -+user-space. -+ -+ -+Major&minor allocation -+ -+The existing scheme requires the allocation of major and minor device -+numbers for each and every device. This means that a central -+co-ordinating authority is required to issue these device numbers -+(unless you're developing a "private" device driver), in order to -+preserve uniqueness. Devfs shifts the burden to a namespace. This may -+not seem like a huge benefit, but actually it is. Since driver authors -+will naturally choose a device name which reflects the functionality -+of the device, there is far less potential for namespace conflict. -+Solving this requires a kernel change. -+ -+/dev management -+ -+Because you currently access devices through device nodes, these must -+be created by the system administrator. For standard devices you can -+usually find a MAKEDEV programme which creates all these (hundreds!) -+of nodes. This means that changes in the kernel must be reflected by -+changes in the MAKEDEV programme, or else the system administrator -+creates device nodes by hand. -+ -+The basic problem is that there are two separate databases of -+major and minor numbers. One is in the kernel and one is in /dev (or -+in a MAKEDEV programme, if you want to look at it that way). This is -+duplication of information, which is not good practice. -+Solving this requires a kernel change. -+ -+/dev growth -+ -+A typical /dev has over 1200 nodes! Most of these devices simply don't -+exist because the hardware is not available. A huge /dev increases the -+time to access devices (I'm just referring to the dentry lookup times -+and the time taken to read inodes off disc: the next subsection shows -+some more horrors). -+ -+An example of how big /dev can grow is if we consider SCSI devices: -+ -+host 6 bits (say up to 64 hosts on a really big machine) -+channel 4 bits (say up to 16 SCSI buses per host) -+id 4 bits -+lun 3 bits -+partition 6 bits -+TOTAL 23 bits -+ -+ -+This requires 8 Mega (1024*1024) inodes if we want to store all -+possible device nodes. Even if we scrap everything but id,partition -+and assume a single host adapter with a single SCSI bus and only one -+logical unit per SCSI target (id), that's still 10 bits or 1024 -+inodes. Each VFS inode takes around 256 bytes (kernel 2.1.78), so -+that's 256 kBytes of inode storage on disc (assuming real inodes take -+a similar amount of space as VFS inodes). This is actually not so bad, -+because disc is cheap these days. Embedded systems would care about -+256 kBytes of /dev inodes, but you could argue that embedded systems -+would have hand-tuned /dev directories. I've had to do just that on my -+embedded systems, but I would rather just leave it to devfs. -+ -+Another issue is the time taken to lookup an inode when first -+referenced. Not only does this take time in scanning through a list in -+memory, but also the seek times to read the inodes off disc. -+This could be solved in user-space using a clever programme which -+scanned the kernel logs and deleted /dev entries which are not -+available and created them when they were available. This programme -+would need to be run every time a new module was loaded, which would -+slow things down a lot. -+ -+There is an existing programme called scsidev which will automatically -+create device nodes for SCSI devices. It can do this by scanning files -+in /proc/scsi. Unfortunately, to extend this idea to other device -+nodes would require significant modifications to existing drivers (so -+they too would provide information in /proc). This is a non-trivial -+change (I should know: devfs has had to do something similar). Once -+you go to this much effort, you may as well use devfs itself (which -+also provides this information). Furthermore, such a system would -+likely be implemented in an ad-hoc fashion, as different drivers will -+provide their information in different ways. -+ -+Devfs is much cleaner, because it (naturally) has a uniform mechanism -+to provide this information: the device nodes themselves! -+ -+ -+Node to driver file_operations translation -+ -+There is an important difference between the way disc-based character -+and block nodes and devfs entries make the connection between an entry -+in /dev and the actual device driver. -+ -+With the current 8 bit major and minor numbers the connection between -+disc-based c&b nodes and per-major drivers is done through a -+fixed-length table of 128 entries. The various filesystem types set -+the inode operations for c&b nodes to {chr,blk}dev_inode_operations, -+so when a device is opened a few quick levels of indirection bring us -+to the driver file_operations. -+ -+For miscellaneous character devices a second step is required: there -+is a scan for the driver entry with the same minor number as the file -+that was opened, and the appropriate minor open method is called. This -+scanning is done *every time* you open a device node. Potentially, you -+may be searching through dozens of misc. entries before you find your -+open method. While not an enormous performance overhead, this does -+seem pointless. -+ -+Linux *must* move beyond the 8 bit major and minor barrier, -+somehow. If we simply increase each to 16 bits, then the indexing -+scheme used for major driver lookup becomes untenable, because the -+major tables (one each for character and block devices) would need to -+be 64 k entries long (512 kBytes on x86, 1 MByte for 64 bit -+systems). So we would have to use a scheme like that used for -+miscellaneous character devices, which means the search time goes up -+linearly with the average number of major device drivers on your -+system. Not all "devices" are hardware, some are higher-level drivers -+like KGI, so you can get more "devices" without adding hardware -+You can improve this by creating an ordered (balanced:-) -+binary tree, in which case your search time becomes log(N). -+Alternatively, you can use hashing to speed up the search. -+But why do that search at all if you don't have to? Once again, it -+seems pointless. -+ -+Note that devfs doesn't use the major&minor system. For devfs -+entries, the connection is done when you lookup the /dev entry. When -+devfs_register() is called, an internal table is appended which has -+the entry name and the file_operations. If the dentry cache doesn't -+have the /dev entry already, this internal table is scanned to get the -+file_operations, and an inode is created. If the dentry cache already -+has the entry, there is *no lookup time* (other than the dentry scan -+itself, but we can't avoid that anyway, and besides Linux dentries -+cream other OS's which don't have them:-). Furthermore, the number of -+node entries in a devfs is only the number of available device -+entries, not the number of *conceivable* entries. Even if you remove -+unnecessary entries in a disc-based /dev, the number of conceivable -+entries remains the same: you just limit yourself in order to save -+space. -+ -+Devfs provides a fast connection between a VFS node and the device -+driver, in a scalable way. -+ -+/dev as a system administration tool -+ -+Right now /dev contains a list of conceivable devices, most of which I -+don't have. Devfs only shows those devices available on my -+system. This means that listing /dev is a handy way of checking what -+devices are available. -+ -+Major&minor size -+ -+Existing major and minor numbers are limited to 8 bits each. This is -+now a limiting factor for some drivers, particularly the SCSI disc -+driver, which consumes a single major number. Only 16 discs are -+supported, and each disc may have only 15 partitions. Maybe this isn't -+a problem for you, but some of us are building huge Linux systems with -+disc arrays. With devfs an arbitrary pointer can be associated with -+each device entry, which can be used to give an effective 32 bit -+device identifier (i.e. that's like having a 32 bit minor -+number). Since this is private to the kernel, there are no C library -+compatibility issues which you would have with increasing major and -+minor number sizes. See the section on "Allocation of Device Numbers" -+for details on maintaining compatibility with userspace. -+ -+Solving this requires a kernel change. -+ -+Since writing this, the kernel has been modified so that the SCSI disc -+driver has more major numbers allocated to it and now supports up to -+128 discs. Since these major numbers are non-contiguous (a result of -+unplanned expansion), the implementation is a little more cumbersome -+than originally. -+ -+Just like the changes to IPv4 to fix impending limitations in the -+address space, people find ways around the limitations. In the long -+run, however, solutions like IPv6 or devfs can't be put off forever. -+ -+Read-only root filesystem -+ -+Having your device nodes on the root filesystem means that you can't -+operate properly with a read-only root filesystem. This is because you -+want to change ownerships and protections of tty devices. Existing -+practice prevents you using a CD-ROM as your root filesystem for a -+*real* system. Sure, you can boot off a CD-ROM, but you can't change -+tty ownerships, so it's only good for installing. -+ -+Also, you can't use a shared NFS root filesystem for a cluster of -+discless Linux machines (having tty ownerships changed on a common -+/dev is not good). Nor can you embed your root filesystem in a -+ROM-FS. -+ -+You can get around this by creating a RAMDISC at boot time, making -+an ext2 filesystem in it, mounting it somewhere and copying the -+contents of /dev into it, then unmounting it and mounting it over -+/dev. -+ -+A devfs is a cleaner way of solving this. -+ -+Non-Unix root filesystem -+ -+Non-Unix filesystems (such as NTFS) can't be used for a root -+filesystem because they variously don't support character and block -+special files or symbolic links. You can't have a separate disc-based -+or RAMDISC-based filesystem mounted on /dev because you need device -+nodes before you can mount these. Devfs can be mounted without any -+device nodes. Devlinks won't work because symlinks aren't supported. -+An alternative solution is to use initrd to mount a RAMDISC initial -+root filesystem (which is populated with a minimal set of device -+nodes), and then construct a new /dev in another RAMDISC, and finally -+switch to your non-Unix root filesystem. This requires clever boot -+scripts and a fragile and conceptually complex boot procedure. -+ -+Devfs solves this in a robust and conceptually simple way. -+ -+PTY security -+ -+Current pseudo-tty (pty) devices are owned by root and read-writable -+by everyone. The user of a pty-pair cannot change -+ownership/protections without being suid-root. -+ -+This could be solved with a secure user-space daemon which runs as -+root and does the actual creation of pty-pairs. Such a daemon would -+require modification to *every* programme that wants to use this new -+mechanism. It also slows down creation of pty-pairs. -+ -+An alternative is to create a new open_pty() syscall which does much -+the same thing as the user-space daemon. Once again, this requires -+modifications to pty-handling programmes. -+ -+The devfs solution allows a device driver to "tag" certain device -+files so that when an unopened device is opened, the ownerships are -+changed to the current euid and egid of the opening process, and the -+protections are changed to the default registered by the driver. When -+the device is closed ownership is set back to root and protections are -+set back to read-write for everybody. No programme need be changed. -+The devpts filesystem provides this auto-ownership feature for Unix98 -+ptys. It doesn't support old-style pty devices, nor does it have all -+the other features of devfs. -+ -+Intelligent device management -+ -+Devfs implements a simple yet powerful protocol for communication with -+a device management daemon (devfsd) which runs in user space. It is -+possible to send a message (either synchronously or asynchronously) to -+devfsd on any event, such as registration/unregistration of device -+entries, opening and closing devices, looking up inodes, scanning -+directories and more. This has many possibilities. Some of these are -+already implemented. See: -+ -+ -+http://www.atnf.csiro.au/~rgooch/linux/ -+ -+Device entry registration events can be used by devfsd to change -+permissions of newly-created device nodes. This is one mechanism to -+control device permissions. -+ -+Device entry registration/unregistration events can be used to run -+programmes or scripts. This can be used to provide automatic mounting -+of filesystems when a new block device media is inserted into the -+drive. -+ -+Asynchronous device open and close events can be used to implement -+clever permissions management. For example, the default permissions on -+/dev/dsp do not allow everybody to read from the device. This is -+sensible, as you don't want some remote user recording what you say at -+your console. However, the console user is also prevented from -+recording. This behaviour is not desirable. With asynchronous device -+open and close events, you can have devfsd run a programme or script -+when console devices are opened to change the ownerships for *other* -+device nodes (such as /dev/dsp). On closure, you can run a different -+script to restore permissions. An advantage of this scheme over -+modifying the C library tty handling is that this works even if your -+programme crashes (how many times have you seen the utmp database with -+lingering entries for non-existent logins?). -+ -+Synchronous device open events can be used to perform intelligent -+device access protections. Before the device driver open() method is -+called, the daemon must first validate the open attempt, by running an -+external programme or script. This is far more flexible than access -+control lists, as access can be determined on the basis of other -+system conditions instead of just the UID and GID. -+ -+Inode lookup events can be used to authenticate module autoload -+requests. Instead of using kmod directly, the event is sent to -+devfsd which can implement an arbitrary authentication before loading -+the module itself. -+ -+Inode lookup events can also be used to construct arbitrary -+namespaces, without having to resort to populating devfs with symlinks -+to devices that don't exist. -+ -+Speculative Device Scanning -+ -+Consider an application (like cdparanoia) that wants to find all -+CD-ROM devices on the system (SCSI, IDE and other types), whether or -+not their respective modules are loaded. The application must -+speculatively open certain device nodes (such as /dev/sr0 for the SCSI -+CD-ROMs) in order to make sure the module is loaded. This requires -+that all Linux distributions follow the standard device naming scheme -+(last time I looked RedHat did things differently). Devfs solves the -+naming problem. -+ -+The same application also wants to see which devices are actually -+available on the system. With the existing system it needs to read the -+/dev directory and speculatively open each /dev/sr* device to -+determine if the device exists or not. With a large /dev this is an -+inefficient operation, especially if there are many /dev/sr* nodes. A -+solution like scsidev could reduce the number of /dev/sr* entries (but -+of course that also requires all that inefficient directory scanning). -+ -+With devfs, the application can open the /dev/sr directory -+(which triggers the module autoloading if required), and proceed to -+read /dev/sr. Since only the available devices will have -+entries, there are no inefficencies in directory scanning or device -+openings. -+ -+----------------------------------------------------------------------------- -+ -+Who else does it? -+ -+FreeBSD has a devfs implementation. Solaris and AIX each have a -+pseudo-devfs (something akin to scsidev but for all devices, with some -+unspecified kernel support). BeOS, Plan9 and QNX also have it. SGI's -+IRIX 6.4 and above also have a device filesystem. -+ -+While we shouldn't just automatically do something because others do -+it, we should not ignore the work of others either. FreeBSD has a lot -+of competent people working on it, so their opinion should not be -+blithely ignored. -+ -+----------------------------------------------------------------------------- -+ -+ -+How it works -+ -+Registering device entries -+ -+For every entry (device node) in a devfs-based /dev a driver must call -+devfs_register(). This adds the name of the device entry, the -+file_operations structure pointer and a few other things to an -+internal table. Device entries may be added and removed at any -+time. When a device entry is registered, it automagically appears in -+any mounted devfs'. -+ -+Inode lookup -+ -+When a lookup operation on an entry is performed and if there is no -+driver information for that entry devfs will attempt to call -+devfsd. If still no driver information can be found then a negative -+dentry is yielded and the next stage operation will be called by the -+VFS (such as create() or mknod() inode methods). If driver information -+can be found, an inode is created (if one does not exist already) and -+all is well. -+ -+Manually creating device nodes -+ -+The mknod() method allows you to create an ordinary named pipe in the -+devfs, or you can create a character or block special inode if one -+does not already exist. You may wish to create a character or block -+special inode so that you can set permissions and ownership. Later, if -+a device driver registers an entry with the same name, the -+permissions, ownership and times are retained. This is how you can set -+the protections on a device even before the driver is loaded. Once you -+create an inode it appears in the directory listing. -+ -+Unregistering device entries -+ -+A device driver calls devfs_unregister() to unregister an entry. -+ -+Chroot() gaols -+ -+2.2.x kernels -+ -+The semantics of inode creation are different when devfs is mounted -+with the "explicit" option. Now, when a device entry is registered, it -+will not appear until you use mknod() to create the device. It doesn't -+matter if you mknod() before or after the device is registered with -+devfs_register(). The purpose of this behaviour is to support -+chroot(2) gaols, where you want to mount a minimal devfs inside the -+gaol. Only the devices you specifically want to be available (through -+your mknod() setup) will be accessible. -+ -+2.4.x kernels -+ -+As of kernel 2.3.99, the VFS has had the ability to rebind parts of -+the global filesystem namespace into another part of the namespace. -+This now works even at the leaf-node level, which means that -+individual files and device nodes may be bound into other parts of the -+namespace. This is like making links, but better, because it works -+across filesystems (unlike hard links) and works through chroot() -+gaols (unlike symbolic links). -+ -+Because of these improvements to the VFS, the multi-mount capability -+in devfs is no longer needed. The administrator may create a minimal -+device tree inside a chroot(2) gaol by using VFS bindings. As this -+provides most of the features of the devfs multi-mount capability, I -+removed the multi-mount support code (after issuing an RFC). This -+yielded code size reductions and simplifications. -+ -+If you want to construct a minimal chroot() gaol, the following -+command should suffice: -+ -+mount --bind /dev/null /gaol/dev/null -+ -+ -+Repeat for other device nodes you want to expose. Simple! -+ -+----------------------------------------------------------------------------- -+ -+ -+Operational issues -+ -+ -+Instructions for the impatient -+ -+Nobody likes reading documentation. People just want to get in there -+and play. So this section tells you quickly the steps you need to take -+to run with devfs mounted over /dev. Skip these steps and you will end -+up with a nearly unbootable system. Subsequent sections describe the -+issues in more detail, and discuss non-essential configuration -+options. -+ -+Devfsd -+OK, if you're reading this, I assume you want to play with -+devfs. First you should ensure that /usr/src/linux contains a -+recent kernel source tree. Then you need to compile devfsd, the device -+management daemon, available at -+ -+http://www.atnf.csiro.au/~rgooch/linux/. -+Because the kernel has a naming scheme -+which is quite different from the old naming scheme, you need to -+install devfsd so that software and configuration files that use the -+old naming scheme will not break. -+ -+Compile and install devfsd. You will be provided with a default -+configuration file /etc/devfsd.conf which will provide -+compatibility symlinks for the old naming scheme. Don't change this -+config file unless you know what you're doing. Even if you think you -+do know what you're doing, don't change it until you've followed all -+the steps below and booted a devfs-enabled system and verified that it -+works. -+ -+Now edit your main system boot script so that devfsd is started at the -+very beginning (before any filesystem -+checks). /etc/rc.d/rc.sysinit is often the main boot script -+on systems with SysV-style boot scripts. On systems with BSD-style -+boot scripts it is often /etc/rc. Also check -+/sbin/rc. -+ -+NOTE that the line you put into the boot -+script should be exactly: -+ -+/sbin/devfsd /dev -+ -+DO NOT use some special daemon-launching -+programme, otherwise the boot script may not wait for devfsd to finish -+initialising. -+ -+System Libraries -+There may still be some problems because of broken software making -+assumptions about device names. In particular, some software does not -+handle devices which are symbolic links. If you are running a libc 5 -+based system, install libc 5.4.44 (if you have libc 5.4.46, go back to -+libc 5.4.44, which is actually correct). If you are running a glibc -+based system, make sure you have glibc 2.1.3 or later. -+ -+/etc/securetty -+PAM (Pluggable Authentication Modules) is supposed to be a flexible -+mechanism for providing better user authentication and access to -+services. Unfortunately, it's also fragile, complex and undocumented -+(check out RedHat 6.1, and probably other distributions as well). PAM -+has problems with symbolic links. Append the following lines to your -+/etc/securetty file: -+ -+vc/1 -+vc/2 -+vc/3 -+vc/4 -+vc/5 -+vc/6 -+vc/7 -+vc/8 -+ -+This will not weaken security. If you have a version of util-linux -+earlier than 2.10.h, please upgrade to 2.10.h or later. If you -+absolutely cannot upgrade, then also append the following lines to -+your /etc/securetty file: -+ -+1 -+2 -+3 -+4 -+5 -+6 -+7 -+8 -+ -+This may potentially weaken security by allowing root logins over the -+network (a password is still required, though). However, since there -+are problems with dealing with symlinks, I'm suspicious of the level -+of security offered in any case. -+ -+XFree86 -+While not essential, it's probably a good idea to upgrade to XFree86 -+4.0, as patches went in to make it more devfs-friendly. If you don't, -+you'll probably need to apply the following patch to -+/etc/security/console.perms so that ordinary users can run -+startx. Note that not all distributions have this file (e.g. Debian), -+so if it's not present, don't worry about it. -+ -+--- /etc/security/console.perms.orig Sat Apr 17 16:26:47 1999 -++++ /etc/security/console.perms Fri Feb 25 23:53:55 2000 -+@@ -14,7 +14,7 @@ -+ # man 5 console.perms -+ -+ # file classes -- these are regular expressions -+-=tty[0-9][0-9]* :[0-9]\.[0-9] :[0-9] -++=tty[0-9][0-9]* vc/[0-9][0-9]* :[0-9]\.[0-9] :[0-9] -+ -+ # device classes -- these are shell-style globs -+ =/dev/fd[0-1]* -+ -+If the patch does not apply, then change the line: -+ -+=tty[0-9][0-9]* :[0-9]\.[0-9] :[0-9] -+ -+with: -+ -+=tty[0-9][0-9]* vc/[0-9][0-9]* :[0-9]\.[0-9] :[0-9] -+ -+ -+Disable devpts -+I've had a report of devpts mounted on /dev/pts not working -+correctly. Since devfs will also manage /dev/pts, there is no -+need to mount devpts as well. You should either edit your -+/etc/fstab so devpts is not mounted, or disable devpts from -+your kernel configuration. -+ -+Unsupported drivers -+Not all drivers have devfs support. If you depend on one of these -+drivers, you will need to create a script or tarfile that you can use -+at boot time to create device nodes as appropriate. There is a -+section which describes this. Another -+section lists the drivers which have -+devfs support. -+ -+/dev/mouse -+ -+Many disributions configure /dev/mouse to be the mouse device -+for XFree86 and GPM. I actually think this is a bad idea, because it -+adds another level of indirection. When looking at a config file, if -+you see /dev/mouse you're left wondering which mouse -+is being referred to. Hence I recommend putting the actual mouse -+device (for example /dev/psaux) into your -+/etc/X11/XF86Config file (and similarly for the GPM -+configuration file). -+ -+Alternatively, use the same technique used for unsupported drivers -+described above. -+ -+The Kernel -+Finally, you need to make sure devfs is compiled into your kernel. Set -+CONFIG_EXPERIMENTAL=y, CONFIG_DEVFS_FS=y and CONFIG_DEVFS_MOUNT=y by -+using favourite configuration tool (i.e. make config or -+make xconfig) and then make clean and then recompile your kernel and -+modules. At boot, devfs will be mounted onto /dev. -+ -+If you encounter problems booting (for example if you forgot a -+configuration step), you can pass devfs=nomount at the kernel -+boot command line. This will prevent the kernel from mounting devfs at -+boot time onto /dev. -+ -+In general, a kernel built with CONFIG_DEVFS_FS=y but without mounting -+devfs onto /dev is completely safe, and requires no -+configuration changes. One exception to take note of is when -+LABEL= directives are used in /etc/fstab. In this -+case you will be unable to boot properly. This is because the -+mount(8) programme uses /proc/partitions as part of -+the volume label search process, and the device names it finds are not -+available, because setting CONFIG_DEVFS_FS=y changes the names in -+/proc/partitions, irrespective of whether devfs is mounted. -+ -+Now you've finished all the steps required. You're now ready to boot -+your shiny new kernel. Enjoy. -+ -+Changing the configuration -+ -+OK, you've now booted a devfs-enabled system, and everything works. -+Now you may feel like changing the configuration (common targets are -+/etc/fstab and /etc/devfsd.conf). Since you have a -+system that works, if you make any changes and it doesn't work, you -+now know that you only have to restore your configuration files to the -+default and it will work again. -+ -+ -+Permissions persistence across reboots -+ -+If you don't use mknod(2) to create a device file, nor use chmod(2) or -+chown(2) to change the ownerships/permissions, the inode ctime will -+remain at 0 (the epoch, 12 am, 1-JAN-1970, GMT). Anything with a ctime -+later than this has had it's ownership/permissions changed. Hence, a -+simple script or programme may be used to tar up all changed inodes, -+prior to shutdown. Although effective, many consider this approach a -+kludge. -+ -+A much better approach is to use devfsd to save and restore -+permissions. It may be configured to record changes in permissions and -+will save them in a database (in fact a directory tree), and restore -+these upon boot. This is an efficient method and results in immediate -+saving of current permissions (unlike the tar approach, which saves -+permissions at some unspecified future time). -+ -+The default configuration file supplied with devfsd has config entries -+which you may uncomment to enable persistence management. -+ -+If you decide to use the tar approach anyway, be aware that tar will -+first unlink(2) an inode before creating a new device node. The -+unlink(2) has the effect of breaking the connection between a devfs -+entry and the device driver. If you use the "devfs=only" boot option, -+you lose access to the device driver, requiring you to reload the -+module. I consider this a bug in tar (there is no real need to -+unlink(2) the inode first). -+ -+Alternatively, you can use devfsd to provide more sophisticated -+management of device permissions. You can use devfsd to store -+permissions for whole groups of devices with a single configuration -+entry, rather than the conventional single entry per device entry. -+ -+Permissions database stored in mounted-over /dev -+ -+If you wish to save and restore your device permissions into the -+disc-based /dev while still mounting devfs onto /dev -+you may do so. This requires a 2.4.x kernel (in fact, 2.3.99 or -+later), which has the VFS binding facility. You need to do the -+following to set this up: -+ -+ -+ -+make sure the kernel does not mount devfs at boot time -+ -+ -+make sure you have a correct /dev/console entry in your -+root file-system (where your disc-based /dev lives) -+ -+create the /dev-state directory -+ -+ -+add the following lines near the very beginning of your boot -+scripts: -+ -+mount --bind /dev /dev-state -+mount -t devfs none /dev -+devfsd /dev -+ -+ -+ -+ -+add the following lines to your /etc/devfsd.conf file: -+ -+REGISTER ^pt[sy] IGNORE -+CREATE ^pt[sy] IGNORE -+CHANGE ^pt[sy] IGNORE -+DELETE ^pt[sy] IGNORE -+REGISTER .* COPY /dev-state/$devname $devpath -+CREATE .* COPY $devpath /dev-state/$devname -+CHANGE .* COPY $devpath /dev-state/$devname -+DELETE .* CFUNCTION GLOBAL unlink /dev-state/$devname -+RESTORE /dev-state -+ -+Note that the sample devfsd.conf file contains these lines, -+as well as other sample configurations you may find useful. See the -+devfsd distribution -+ -+ -+reboot. -+ -+ -+ -+ -+Permissions database stored in normal directory -+ -+If you are using an older kernel which doesn't support VFS binding, -+then you won't be able to have the permissions database in a -+mounted-over /dev. However, you can still use a regular -+directory to store the database. The sample /etc/devfsd.conf -+file above may still be used. You will need to create the -+/dev-state directory prior to installing devfsd. If you have -+old permissions in /dev, then just copy (or move) the device -+nodes over to the new directory. -+ -+Which method is better? -+ -+The best method is to have the permissions database stored in the -+mounted-over /dev. This is because you will not need to copy -+device nodes over to /dev-state, and because it allows you to -+switch between devfs and non-devfs kernels, without requiring you to -+copy permissions between /dev-state (for devfs) and -+/dev (for non-devfs). -+ -+ -+Dealing with drivers without devfs support -+ -+Currently, not all device drivers in the kernel have been modified to -+use devfs. Device drivers which do not yet have devfs support will not -+automagically appear in devfs. The simplest way to create device nodes -+for these drivers is to unpack a tarfile containing the required -+device nodes. You can do this in your boot scripts. All your drivers -+will now work as before. -+ -+Hopefully for most people devfs will have enough support so that they -+can mount devfs directly over /dev without losing most functionality -+(i.e. losing access to various devices). As of 22-JAN-1998 (devfs -+patch version 10) I am now running this way. All the devices I have -+are available in devfs, so I don't lose anything. -+ -+WARNING: if your configuration requires the old-style device names -+(i.e. /dev/hda1 or /dev/sda1), you must install devfsd and configure -+it to maintain compatibility entries. It is almost certain that you -+will require this. Note that the kernel creates a compatibility entry -+for the root device, so you don't need initrd. -+ -+Note that you no longer need to mount devpts if you use Unix98 PTYs, -+as devfs can manage /dev/pts itself. This saves you some RAM, as you -+don't need to compile and install devpts. Note that some versions of -+glibc have a bug with Unix98 pty handling on devfs systems. Contact -+the glibc maintainers for a fix. Glibc 2.1.3 has the fix. -+ -+Note also that apart from editing /etc/fstab, other things will need -+to be changed if you *don't* install devfsd. Some software (like the X -+server) hard-wire device names in their source. It really is much -+easier to install devfsd so that compatibility entries are created. -+You can then slowly migrate your system to using the new device names -+(for example, by starting with /etc/fstab), and then limiting the -+compatibility entries that devfsd creates. -+ -+IF YOU CONFIGURE TO MOUNT DEVFS AT BOOT, MAKE SURE YOU INSTALL DEVFSD -+BEFORE YOU BOOT A DEVFS-ENABLED KERNEL! -+ -+Now that devfs has gone into the 2.3.46 kernel, I'm getting a lot of -+reports back. Many of these are because people are trying to run -+without devfsd, and hence some things break. Please just run devfsd if -+things break. I want to concentrate on real bugs rather than -+misconfiguration problems at the moment. If people are willing to fix -+bugs/false assumptions in other code (i.e. glibc, X server) and submit -+that to the respective maintainers, that would be great. -+ -+ -+All the way with Devfs -+ -+The devfs kernel patch creates a rationalised device tree. As stated -+above, if you want to keep using the old /dev naming scheme, -+you just need to configure devfsd appopriately (see the man -+page). People who prefer the old names can ignore this section. For -+those of us who like the rationalised names and an uncluttered -+/dev, read on. -+ -+If you don't run devfsd, or don't enable compatibility entry -+management, then you will have to configure your system to use the new -+names. For example, you will then need to edit your -+/etc/fstab to use the new disc naming scheme. If you want to -+be able to boot non-devfs kernels, you will need compatibility -+symlinks in the underlying disc-based /dev pointing back to -+the old-style names for when you boot a kernel without devfs. -+ -+You can selectively decide which devices you want compatibility -+entries for. For example, you may only want compatibility entries for -+BSD pseudo-terminal devices (otherwise you'll have to patch you C -+library or use Unix98 ptys instead). It's just a matter of putting in -+the correct regular expression into /dev/devfsd.conf. -+ -+There are other choices of naming schemes that you may prefer. For -+example, I don't use the kernel-supplied -+names, because they are too verbose. A common misconception is -+that the kernel-supplied names are meant to be used directly in -+configuration files. This is not the case. They are designed to -+reflect the layout of the devices attached and to provide easy -+classification. -+ -+If you like the kernel-supplied names, that's fine. If you don't then -+you should be using devfsd to construct a namespace more to your -+liking. Devfsd has built-in code to construct a -+namespace that is both logical and easy to -+manage. In essence, it creates a convenient abbreviation of the -+kernel-supplied namespace. -+ -+You are of course free to build your own namespace. Devfsd has all the -+infrastructure required to make this easy for you. All you need do is -+write a script. You can even write some C code and devfsd can load the -+shared object as a callable extension. -+ -+ -+Other Issues -+ -+The init programme -+Another thing to take note of is whether your init programme -+creates a Unix socket /dev/telinit. Some versions of init -+create /dev/telinit so that the telinit programme can -+communicate with the init process. If you have such a system you need -+to make sure that devfs is mounted over /dev *before* init -+starts. In other words, you can't leave the mounting of devfs to -+/etc/rc, since this is executed after init. Other -+versions of init require a named pipe /dev/initctl -+which must exist *before* init starts. Once again, you need to -+mount devfs and then create the named pipe *before* init -+starts. -+ -+The default behaviour now is not to mount devfs onto /dev at -+boot time for 2.3.x and later kernels. You can correct this with the -+"devfs=mount" boot option. This solves any problems with init, -+and also prevents the dreaded: -+ -+Cannot open initial console -+ -+message. For 2.2.x kernels where you need to apply the devfs patch, -+the default is to mount. -+ -+If you have automatic mounting of devfs onto /dev then you -+may need to create /dev/initctl in your boot scripts. The -+following lines should suffice: -+ -+mknod /dev/initctl p -+kill -SIGUSR1 1 # tell init that /dev/initctl now exists -+ -+Alternatively, if you don't want the kernel to mount devfs onto -+/dev then you could use the following procedure is a -+guideline for how to get around /dev/initctl problems: -+ -+# cd /sbin -+# mv init init.real -+# cat > init -+#! /bin/sh -+mount -n -t devfs none /dev -+mknod /dev/initctl p -+exec /sbin/init.real $* -+[control-D] -+# chmod a+x init -+ -+Note that newer versions of init create /dev/initctl -+automatically, so you don't have to worry about this. -+ -+Module autoloading -+You will need to configure devfsd to enable module -+autoloading. The following lines should be placed in your -+/etc/devfsd.conf file: -+ -+LOOKUP .* MODLOAD -+ -+ -+As of devfsd-v1.3.10, a generic /etc/modules.devfs -+configuration file is installed, which is used by the MODLOAD -+action. This should be sufficient for most configurations. If you -+require further configuration, edit your /etc/modules.conf -+file. The way module autoloading work with devfs is: -+ -+ -+a process attempts to lookup a device node (e.g. /dev/fred) -+ -+ -+if that device node does not exist, the full pathname is passed to -+devfsd as a string -+ -+ -+devfsd will pass the string to the modprobe programme (provided the -+configuration line shown above is present), and specifies that -+/etc/modules.devfs is the configuration file -+ -+ -+/etc/modules.devfs includes /etc/modules.conf to -+access local configurations -+ -+modprobe will search it's configuration files, looking for an alias -+that translates the pathname into a module name -+ -+ -+the translated pathname is then used to load the module. -+ -+ -+If you wanted a lookup of /dev/fred to load the -+mymod module, you would require the following configuration -+line in /etc/modules.conf: -+ -+alias /dev/fred mymod -+ -+The /etc/modules.devfs configuration file provides many such -+aliases for standard device names. If you look closely at this file, -+you will note that some modules require multiple alias configuration -+lines. This is required to support module autoloading for old and new -+device names. -+ -+Mounting root off a devfs device -+If you wish to mount root off a devfs device when you pass the -+"devfs=only" boot option, then you need to pass in the -+"root=" option to the kernel when booting. If you use -+LILO, then you must have this in lilo.conf: -+ -+append = "root=" -+ -+Surprised? Yep, so was I. It turns out if you have (as most people -+do): -+ -+root = -+ -+ -+then LILO will determine the device number of and will -+write that device number into a special place in the kernel image -+before starting the kernel, and the kernel will use that device number -+to mount the root filesystem. So, using the "append" variety ensures -+that LILO passes the root filesystem device as a string, which devfs -+can then use. -+ -+Note that this isn't an issue if you don't pass "devfs=only". -+ -+TTY issues -+The ttyname(3) function in some versions of the C library makes -+false assumptions about device entries which are symbolic links. The -+tty(1) programme is one that depends on this function. I've -+written a patch to libc 5.4.43 which fixes this. This has been -+included in libc 5.4.44 and a similar fix is in glibc 2.1.3. -+ -+ -+Kernel Naming Scheme -+ -+The kernel provides a default naming scheme. This scheme is designed -+to make it easy to search for specific devices or device types, and to -+view the available devices. Some device types (such as hard discs), -+have a directory of entries, making it easy to see what devices of -+that class are available. Often, the entries are symbolic links into a -+directory tree that reflects the topology of available devices. The -+topological tree is useful for finding how your devices are arranged. -+ -+Below is a list of the naming schemes for the most common drivers. A -+list of reserved device names is -+available for reference. Please send email to -+rgooch@atnf.csiro.au to obtain an allocation. Please be -+patient (the maintainer is busy). An alternative name may be allocated -+instead of the requested name, at the discretion of the maintainer. -+ -+Disc Devices -+ -+All discs, whether SCSI, IDE or whatever, are placed under the -+/dev/discs hierarchy: -+ -+ /dev/discs/disc0 first disc -+ /dev/discs/disc1 second disc -+ -+ -+Each of these entries is a symbolic link to the directory for that -+device. The device directory contains: -+ -+ disc for the whole disc -+ part* for individual partitions -+ -+ -+CD-ROM Devices -+ -+All CD-ROMs, whether SCSI, IDE or whatever, are placed under the -+/dev/cdroms hierarchy: -+ -+ /dev/cdroms/cdrom0 first CD-ROM -+ /dev/cdroms/cdrom1 second CD-ROM -+ -+ -+Each of these entries is a symbolic link to the real device entry for -+that device. -+ -+Tape Devices -+ -+All tapes, whether SCSI, IDE or whatever, are placed under the -+/dev/tapes hierarchy: -+ -+ /dev/tapes/tape0 first tape -+ /dev/tapes/tape1 second tape -+ -+ -+Each of these entries is a symbolic link to the directory for that -+device. The device directory contains: -+ -+ mt for mode 0 -+ mtl for mode 1 -+ mtm for mode 2 -+ mta for mode 3 -+ mtn for mode 0, no rewind -+ mtln for mode 1, no rewind -+ mtmn for mode 2, no rewind -+ mtan for mode 3, no rewind -+ -+ -+SCSI Devices -+ -+To uniquely identify any SCSI device requires the following -+information: -+ -+ controller (host adapter) -+ bus (SCSI channel) -+ target (SCSI ID) -+ unit (Logical Unit Number) -+ -+ -+All SCSI devices are placed under /dev/scsi (assuming devfs -+is mounted on /dev). Hence, a SCSI device with the following -+parameters: c=1,b=2,t=3,u=4 would appear as: -+ -+ /dev/scsi/host1/bus2/target3/lun4 device directory -+ -+ -+Inside this directory, a number of device entries may be created, -+depending on which SCSI device-type drivers were installed. -+ -+See the section on the disc naming scheme to see what entries the SCSI -+disc driver creates. -+ -+See the section on the tape naming scheme to see what entries the SCSI -+tape driver creates. -+ -+The SCSI CD-ROM driver creates: -+ -+ cd -+ -+ -+The SCSI generic driver creates: -+ -+ generic -+ -+ -+IDE Devices -+ -+To uniquely identify any IDE device requires the following -+information: -+ -+ controller -+ bus (aka. primary/secondary) -+ target (aka. master/slave) -+ unit -+ -+ -+All IDE devices are placed under /dev/ide, and uses a similar -+naming scheme to the SCSI subsystem. -+ -+XT Hard Discs -+ -+All XT discs are placed under /dev/xd. The first XT disc has -+the directory /dev/xd/disc0. -+ -+TTY devices -+ -+The tty devices now appear as: -+ -+ New name Old-name Device Type -+ -------- -------- ----------- -+ /dev/tts/{0,1,...} /dev/ttyS{0,1,...} Serial ports -+ /dev/cua/{0,1,...} /dev/cua{0,1,...} Call out devices -+ /dev/vc/0 /dev/tty Current virtual console -+ /dev/vc/{1,2,...} /dev/tty{1...63} Virtual consoles -+ /dev/vcc/{0,1,...} /dev/vcs{1...63} Virtual consoles -+ /dev/pty/m{0,1,...} /dev/ptyp?? PTY masters -+ /dev/pty/s{0,1,...} /dev/ttyp?? PTY slaves -+ -+ -+RAMDISCS -+ -+The RAMDISCS are placed in their own directory, and are named thus: -+ -+ /dev/rd/{0,1,2,...} -+ -+ -+Meta Devices -+ -+The meta devices are placed in their own directory, and are named -+thus: -+ -+ /dev/md/{0,1,2,...} -+ -+ -+Floppy discs -+ -+Floppy discs are placed in the /dev/floppy directory. -+ -+Loop devices -+ -+Loop devices are placed in the /dev/loop directory. -+ -+Sound devices -+ -+Sound devices are placed in the /dev/sound directory -+(audio, sequencer, ...). -+ -+ -+Devfsd Naming Scheme -+ -+Devfsd provides a naming scheme which is a convenient abbreviation of -+the kernel-supplied namespace. In some -+cases, the kernel-supplied naming scheme is quite convenient, so -+devfsd does not provide another naming scheme. The convenience names -+that devfsd creates are in fact the same names as the original devfs -+kernel patch created (before Linus mandated the Big Name -+Change). These are referred to as "new compatibility entries". -+ -+In order to configure devfsd to create these convenience names, the -+following lines should be placed in your /etc/devfsd.conf: -+ -+REGISTER .* MKNEWCOMPAT -+UNREGISTER .* RMNEWCOMPAT -+ -+This will cause devfsd to create (and destroy) symbolic links which -+point to the kernel-supplied names. -+ -+SCSI Hard Discs -+ -+All SCSI discs are placed under /dev/sd (assuming devfs is -+mounted on /dev). Hence, a SCSI disc with the following -+parameters: c=1,b=2,t=3,u=4 would appear as: -+ -+ /dev/sd/c1b2t3u4 for the whole disc -+ /dev/sd/c1b2t3u4p5 for the 5th partition -+ /dev/sd/c1b2t3u4p5s6 for the 6th slice in the 5th partition -+ -+ -+SCSI Tapes -+ -+All SCSI tapes are placed under /dev/st. A similar naming -+scheme is used as for SCSI discs. A SCSI tape with the -+parameters:c=1,b=2,t=3,u=4 would appear as: -+ -+ /dev/st/c1b2t3u4m0 for mode 0 -+ /dev/st/c1b2t3u4m1 for mode 1 -+ /dev/st/c1b2t3u4m2 for mode 2 -+ /dev/st/c1b2t3u4m3 for mode 3 -+ /dev/st/c1b2t3u4m0n for mode 0, no rewind -+ /dev/st/c1b2t3u4m1n for mode 1, no rewind -+ /dev/st/c1b2t3u4m2n for mode 2, no rewind -+ /dev/st/c1b2t3u4m3n for mode 3, no rewind -+ -+ -+SCSI CD-ROMs -+ -+All SCSI CD-ROMs are placed under /dev/sr. A similar naming -+scheme is used as for SCSI discs. A SCSI CD-ROM with the -+parameters:c=1,b=2,t=3,u=4 would appear as: -+ -+ /dev/sr/c1b2t3u4 -+ -+ -+SCSI Generic Devices -+ -+The generic (aka. raw) interface for all SCSI devices are placed under -+/dev/sg. A similar naming scheme is used as for SCSI discs. A -+SCSI generic device with the parameters:c=1,b=2,t=3,u=4 would appear -+as: -+ -+ /dev/sg/c1b2t3u4 -+ -+ -+IDE Hard Discs -+ -+All IDE discs are placed under /dev/ide/hd, using a similar -+convention to SCSI discs. The following mappings exist between the new -+and the old names: -+ -+ /dev/hda /dev/ide/hd/c0b0t0u0 -+ /dev/hdb /dev/ide/hd/c0b0t1u0 -+ /dev/hdc /dev/ide/hd/c0b1t0u0 -+ /dev/hdd /dev/ide/hd/c0b1t1u0 -+ -+ -+IDE Tapes -+ -+A similar naming scheme is used as for IDE discs. The entries will -+appear in the /dev/ide/mt directory. -+ -+IDE CD-ROM -+ -+A similar naming scheme is used as for IDE discs. The entries will -+appear in the /dev/ide/cd directory. -+ -+IDE Floppies -+ -+A similar naming scheme is used as for IDE discs. The entries will -+appear in the /dev/ide/fd directory. -+ -+XT Hard Discs -+ -+All XT discs are placed under /dev/xd. The first XT disc -+would appear as /dev/xd/c0t0. -+ -+ -+Old Compatibility Names -+ -+The old compatibility names are the legacy device names, such as -+/dev/hda, /dev/sda, /dev/rtc and so on. -+Devfsd can be configured to create compatibility symlinks so that you -+may continue to use the old names in your configuration files and so -+that old applications will continue to function correctly. -+ -+In order to configure devfsd to create these legacy names, the -+following lines should be placed in your /etc/devfsd.conf: -+ -+REGISTER .* MKOLDCOMPAT -+UNREGISTER .* RMOLDCOMPAT -+ -+This will cause devfsd to create (and destroy) symbolic links which -+point to the kernel-supplied names. -+ -+ -+----------------------------------------------------------------------------- -+ -+ -+Device drivers currently ported -+ -+- All miscellaneous character devices support devfs (this is done -+ transparently through misc_register()) -+ -+- SCSI discs and generic hard discs -+ -+- Character memory devices (null, zero, full and so on) -+ Thanks to C. Scott Ananian -+ -+- Loop devices (/dev/loop?) -+ -+- TTY devices (console, serial ports, terminals and pseudo-terminals) -+ Thanks to C. Scott Ananian -+ -+- SCSI tapes (/dev/scsi and /dev/tapes) -+ -+- SCSI CD-ROMs (/dev/scsi and /dev/cdroms) -+ -+- SCSI generic devices (/dev/scsi) -+ -+- RAMDISCS (/dev/ram?) -+ -+- Meta Devices (/dev/md*) -+ -+- Floppy discs (/dev/floppy) -+ -+- Parallel port printers (/dev/printers) -+ -+- Sound devices (/dev/sound) -+ Thanks to Eric Dumas and -+ C. Scott Ananian -+ -+- Joysticks (/dev/joysticks) -+ -+- Sparc keyboard (/dev/kbd) -+ -+- DSP56001 digital signal processor (/dev/dsp56k) -+ -+- Apple Desktop Bus (/dev/adb) -+ -+- Coda network file system (/dev/cfs*) -+ -+- Virtual console capture devices (/dev/vcc) -+ Thanks to Dennis Hou -+ -+- Frame buffer devices (/dev/fb) -+ -+- Video capture devices (/dev/v4l) -+ -+ -+----------------------------------------------------------------------------- -+ -+ -+Allocation of Device Numbers -+ -+Devfs allows you to write a driver which doesn't need to allocate a -+device number (major&minor numbers) for the internal operation of the -+kernel. However, there are a number of userspace programmes that use -+the device number as a unique handle for a device. An example is the -+find programme, which uses device numbers to determine whether -+an inode is on a different filesystem than another inode. The device -+number used is the one for the block device which a filesystem is -+using. To preserve compatibility with userspace programmes, block -+devices using devfs need to have unique device numbers allocated to -+them. Furthermore, POSIX specifies device numbers, so some kind of -+device number needs to be presented to userspace. -+ -+The simplest option (especially when porting drivers to devfs) is to -+keep using the old major and minor numbers. Devfs will take whatever -+values are given for major&minor and pass them onto userspace. -+ -+This device number is a 16 bit number, so this leaves plenty of space -+for large numbers of discs and partitions. This scheme can also be -+used for character devices, in particular the tty devices, which are -+currently limited to 256 pseudo-ttys (this limits the total number of -+simultaneous xterms and remote logins). Note that the device number -+is limited to the range 36864-61439 (majors 144-239), in order to -+avoid any possible conflicts with existing official allocations. -+ -+Please note that using dynamically allocated block device numbers may -+break the NFS daemons (both user and kernel mode), which expect dev_t -+for a given device to be constant over the lifetime of remote mounts. -+ -+A final note on this scheme: since it doesn't increase the size of -+device numbers, there are no compatibility issues with userspace. -+ -+----------------------------------------------------------------------------- -+ -+ -+Questions and Answers -+ -+ -+Making things work -+Alternatives to devfs -+What I don't like about devfs -+How to report bugs -+Strange kernel messages -+Compilation problems with devfsd -+ -+ -+ -+Making things work -+ -+Here are some common questions and answers. -+ -+ -+ -+Devfsd doesn't start -+ -+Make sure you have compiled and installed devfsd -+Make sure devfsd is being started from your boot -+scripts -+Make sure you have configured your kernel to enable devfs (see -+below) -+Make sure devfs is mounted (see below) -+ -+ -+Devfsd is not managing all my permissions -+ -+Make sure you are capturing the appropriate events. For example, -+device entries created by the kernel generate REGISTER events, -+but those created by devfsd generate CREATE events. -+ -+ -+Devfsd is not capturing all REGISTER events -+ -+See the previous entry: you may need to capture CREATE events. -+ -+ -+X will not start -+ -+Make sure you followed the steps -+outlined above. -+ -+ -+Why don't my network devices appear in devfs? -+ -+This is not a bug. Network devices have their own, completely separate -+namespace. They are accessed via socket(2) and -+setsockopt(2) calls, and thus require no device nodes. I have -+raised the possibilty of moving network devices into the device -+namespace, but have had no response. -+ -+ -+How can I test if I have devfs compiled into my kernel? -+ -+All filesystems built-in or currently loaded are listed in -+/proc/filesystems. If you see a devfs entry, then -+you know that devfs was compiled into your kernel. If you have -+correctly configured and rebuilt your kernel, then devfs will be -+built-in. If you think you've configured it in, but -+/proc/filesystems doesn't show it, you've made a mistake. -+Common mistakes include: -+ -+Using a 2.2.x kernel without applying the devfs patch (if you -+don't know how to patch your kernel, use 2.4.x instead, don't bother -+asking me how to patch) -+Forgetting to set CONFIG_EXPERIMENTAL=y -+Forgetting to set CONFIG_DEVFS_FS=y -+Forgetting to set CONFIG_DEVFS_MOUNT=y (if you want devfs -+to be automatically mounted at boot) -+Editing your .config manually, instead of using make -+config or make xconfig -+Forgetting to run make dep; make clean after changing the -+configuration and before compiling -+Forgetting to compile your kernel and modules -+Forgetting to install your kernel -+Forgetting to install your modules -+ -+Please check twice that you've done all these steps before sending in -+a bug report. -+ -+ -+ -+How can I test if devfs is mounted on /dev? -+ -+The device filesystem will always create an entry called -+".devfsd", which is used to communicate with the daemon. Even -+if the daemon is not running, this entry will exist. Testing for the -+existence of this entry is the approved method of determining if devfs -+is mounted or not. Note that the type of entry (i.e. regular file, -+character device, named pipe, etc.) may change without notice. Only -+the existence of the entry should be relied upon. -+ -+ -+When I start devfsd, I see the error: -+Error opening file: ".devfsd" No such file or directory? -+ -+This means that devfs is not mounted. Make sure you have devfs mounted. -+ -+ -+How do I mount devfs? -+ -+First make sure you have devfs compiled into your kernel (see -+above). Then you will either need to: -+ -+set CONFIG_DEVFS_MOUNT=y in your kernel config -+pass devfs=mount to your boot loader -+mount devfs manually in your boot scripts with: -+mount -t none devfs /dev -+ -+ -+ -+Mount by volume LABEL=