initramfs: Use KBUILD_BUILD_TIMESTAMP for generated entries

gen_init_cpio gets the current time and uses it for each symlink,
special file, and directory.  Grab the current time once and make it
possible to override it with the KBUILD_BUILD_TIMESTAMP variable for
reproducible builds.

Signed-off-by: Michal Marek <mmarek@suse.cz>

diff --git a/Documentation/kbuild/kbuild.txt b/Documentation/kbuild/kbuild.txt
index f11ebb33e4a6eea15a80dd49873619c4d2ee9253..646e2c114ffff37a23dadb5c55aff7282e0aa76a 100644 (file)
--- a/Documentation/kbuild/kbuild.txt
+++ b/Documentation/kbuild/kbuild.txt
@@ -205,7 +205,8 @@ gcc -W... options for more extensive build-time checking.
 KBUILD_BUILD_TIMESTAMP
 --------------------------------------------------
 Setting this to a date string overrides the timestamp used in the
-UTS_VERSION definition (uname -v in the running kernel). The default value
+UTS_VERSION definition (uname -v in the running kernel). The value has to
+be a string that can be passed to date -d. The default value
 is the output of the date command at one point during build.
 
 KBUILD_BUILD_USER, KBUILD_BUILD_HOST

diff --git a/scripts/gen_initramfs_list.sh b/scripts/gen_initramfs_list.sh
index 4a43fe12d1792c8f150302d47755d34a82f1a497..d44cf675bc22a6ac942500ad471cc27a5ebf9828 100644 (file)
--- a/scripts/gen_initramfs_list.sh
+++ b/scripts/gen_initramfs_list.sh
@@ -287,8 +287,15 @@ done
 # we are carefull to delete tmp files
 if [ ! -z ${output_file} ]; then
        if [ -z ${cpio_file} ]; then
+               timestamp=
+               if test -n "$KBUILD_BUILD_TIMESTAMP"; then
+                       timestamp="$(date -d"$KBUILD_BUILD_TIMESTAMP" +%s || :)"
+                       if test -n "$timestamp"; then
+                               timestamp="-t $timestamp"
+                       fi
+               fi
                cpio_tfile="$(mktemp ${TMPDIR:-/tmp}/cpiofile.XXXXXX)"
-               usr/gen_init_cpio ${cpio_list} > ${cpio_tfile}
+               usr/gen_init_cpio $timestamp ${cpio_list} > ${cpio_tfile}
        else
                cpio_tfile=${cpio_file}
        fi

diff --git a/usr/gen_init_cpio.c b/usr/gen_init_cpio.c
index 7f06884ecd41b588d829064a53ac964395b0ae1e..af0f22fb1ef71e6dc94c620873bc3241c2883430 100644 (file)
--- a/usr/gen_init_cpio.c
+++ b/usr/gen_init_cpio.c
@@ -22,6 +22,7 @@
 
 static unsigned int offset;
 static unsigned int ino = 721;
+static time_t default_mtime;
 
 struct file_handler {
        const char *type;
@@ -102,7 +103,6 @@ static int cpio_mkslink(const char *name, const char *target,
                         unsigned int mode, uid_t uid, gid_t gid)
 {
        char s[256];
-       time_t mtime = time(NULL);
 
        if (name[0] == '/')
                name++;
@@ -114,7 +114,7 @@ static int cpio_mkslink(const char *name, const char *target,
                (long) uid,             /* uid */
                (long) gid,             /* gid */
                1,                      /* nlink */
-               (long) mtime,           /* mtime */
+               (long) default_mtime,   /* mtime */
                (unsigned)strlen(target)+1, /* filesize */
                3,                      /* major */
                1,                      /* minor */
@@ -152,7 +152,6 @@ static int cpio_mkgeneric(const char *name, unsigned int mode,
                       uid_t uid, gid_t gid)
 {
        char s[256];
-       time_t mtime = time(NULL);
 
        if (name[0] == '/')
                name++;
@@ -164,7 +163,7 @@ static int cpio_mkgeneric(const char *name, unsigned int mode,
                (long) uid,             /* uid */
                (long) gid,             /* gid */
                2,                      /* nlink */
-               (long) mtime,           /* mtime */
+               (long) default_mtime,   /* mtime */
                0,                      /* filesize */
                3,                      /* major */
                1,                      /* minor */
@@ -242,7 +241,6 @@ static int cpio_mknod(const char *name, unsigned int mode,
                       unsigned int maj, unsigned int min)
 {
        char s[256];
-       time_t mtime = time(NULL);
 
        if (dev_type == 'b')
                mode |= S_IFBLK;
@@ -259,7 +257,7 @@ static int cpio_mknod(const char *name, unsigned int mode,
                (long) uid,             /* uid */
                (long) gid,             /* gid */
                1,                      /* nlink */
-               (long) mtime,           /* mtime */
+               (long) default_mtime,   /* mtime */
                0,                      /* filesize */
                3,                      /* major */
                1,                      /* minor */
@@ -460,7 +458,7 @@ static int cpio_mkfile_line(const char *line)
 static void usage(const char *prog)
 {
        fprintf(stderr, "Usage:\n"
-               "\t%s <cpio_list>\n"
+               "\t%s [-t <timestamp>] <cpio_list>\n"
                "\n"
                "<cpio_list> is a file containing newline separated entries that\n"
                "describe the files to be included in the initramfs archive:\n"
@@ -491,7 +489,11 @@ static void usage(const char *prog)
                "nod /dev/console 0600 0 0 c 5 1\n"
                "dir /root 0700 0 0\n"
                "dir /sbin 0755 0 0\n"
-               "file /sbin/kinit /usr/src/klibc/kinit/kinit 0755 0 0\n",
+               "file /sbin/kinit /usr/src/klibc/kinit/kinit 0755 0 0\n"
+               "\n"
+               "<timestamp> is time in seconds since Epoch that will be used\n"
+               "as mtime for symlinks, special files and directories. The default\n"
+               "is to use the current time for these entries.\n",
                prog);
 }
 
@@ -529,17 +531,42 @@ int main (int argc, char *argv[])
        char *args, *type;
        int ec = 0;
        int line_nr = 0;
+       const char *filename;
+
+       default_mtime = time(NULL);
+       while (1) {
+               int opt = getopt(argc, argv, "t:h");
+               char *invalid;
 
-       if (2 != argc) {
+               if (opt == -1)
+                       break;
+               switch (opt) {
+               case 't':
+                       default_mtime = strtol(optarg, &invalid, 10);
+                       if (!*optarg || *invalid) {
+                               fprintf(stderr, "Invalid timestamp: %s\n",
+                                               optarg);
+                               usage(argv[0]);
+                               exit(1);
+                       }
+                       break;
+               case 'h':
+               case '?':
+                       usage(argv[0]);
+                       exit(opt == 'h' ? 0 : 1);
+               }
+       }
+
+       if (argc - optind != 1) {
                usage(argv[0]);
                exit(1);
        }
-
-       if (!strcmp(argv[1], "-"))
+       filename = argv[optind];
+       if (!strcmp(filename, "-"))
                cpio_list = stdin;
-       else if (! (cpio_list = fopen(argv[1], "r"))) {
+       else if (!(cpio_list = fopen(filename, "r"))) {
                fprintf(stderr, "ERROR: unable to open '%s': %s\n\n",
-                       argv[1], strerror(errno));
+                       filename, strerror(errno));
                usage(argv[0]);
                exit(1);
        }