From: Al Viro Date: Fri, 11 Mar 2011 17:08:24 +0000 (-0500) Subject: open-style analog of vfs_path_lookup() X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=73d049a40fc6269189c4e2ba6792cb5dd054883c;p=openwrt%2Fstaging%2Fblogic.git open-style analog of vfs_path_lookup() new function: file_open_root(dentry, mnt, name, flags) opens the file vfs_path_lookup would arrive to. Note that name can be empty; in that case the usual requirement that dentry should be a directory is lifted. open-coded equivalents switched to it, may_open() got down exactly one caller and became static. Signed-off-by: Al Viro --- diff --git a/arch/um/drivers/mconsole_kern.c b/arch/um/drivers/mconsole_kern.c index 975613b23dcf..c70e047eed72 100644 --- a/arch/um/drivers/mconsole_kern.c +++ b/arch/um/drivers/mconsole_kern.c @@ -124,35 +124,18 @@ void mconsole_log(struct mc_request *req) #if 0 void mconsole_proc(struct mc_request *req) { - struct nameidata nd; struct vfsmount *mnt = current->nsproxy->pid_ns->proc_mnt; struct file *file; - int n, err; + int n; char *ptr = req->request.data, *buf; mm_segment_t old_fs = get_fs(); ptr += strlen("proc"); ptr = skip_spaces(ptr); - err = vfs_path_lookup(mnt->mnt_root, mnt, ptr, LOOKUP_FOLLOW, &nd); - if (err) { - mconsole_reply(req, "Failed to look up file", 1, 0); - goto out; - } - - err = may_open(&nd.path, MAY_READ, O_RDONLY); - if (result) { - mconsole_reply(req, "Failed to open file", 1, 0); - path_put(&nd.path); - goto out; - } - - file = dentry_open(nd.path.dentry, nd.path.mnt, O_RDONLY, - current_cred()); - err = PTR_ERR(file); + file = file_open_root(mnt->mnt_root, mnt, ptr, O_RDONLY); if (IS_ERR(file)) { mconsole_reply(req, "Failed to open file", 1, 0); - path_put(&nd.path); goto out; } diff --git a/fs/internal.h b/fs/internal.h index 6fdbdf2c6047..52abc5287f50 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -114,6 +114,8 @@ struct open_flags { }; extern struct file *do_filp_open(int dfd, const char *pathname, const struct open_flags *op, int lookup_flags); +extern struct file *do_file_open_root(struct dentry *, struct vfsmount *, + const char *, const struct open_flags *, int lookup_flags); /* * inode.c diff --git a/fs/namei.c b/fs/namei.c index 8ee7785d5642..abc8d2df121c 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1487,11 +1487,13 @@ static int path_init(int dfd, const char *name, unsigned int flags, nd->depth = 0; if (flags & LOOKUP_ROOT) { struct inode *inode = nd->root.dentry->d_inode; - if (!inode->i_op->lookup) - return -ENOTDIR; - retval = inode_permission(inode, MAY_EXEC); - if (retval) - return retval; + if (*name) { + if (!inode->i_op->lookup) + return -ENOTDIR; + retval = inode_permission(inode, MAY_EXEC); + if (retval) + return retval; + } nd->path = nd->root; nd->inode = inode; if (flags & LOOKUP_RCU) { @@ -1937,7 +1939,7 @@ int vfs_create(struct inode *dir, struct dentry *dentry, int mode, return error; } -int may_open(struct path *path, int acc_mode, int flag) +static int may_open(struct path *path, int acc_mode, int flag) { struct dentry *dentry = path->dentry; struct inode *inode = dentry->d_inode; @@ -2250,11 +2252,10 @@ exit: } static struct file *path_openat(int dfd, const char *pathname, - const struct open_flags *op, int flags) + struct nameidata *nd, const struct open_flags *op, int flags) { struct file *base = NULL; struct file *filp; - struct nameidata nd; struct path path; int count = 0; int error; @@ -2264,27 +2265,27 @@ static struct file *path_openat(int dfd, const char *pathname, return ERR_PTR(-ENFILE); filp->f_flags = op->open_flag; - nd.intent.open.file = filp; - nd.intent.open.flags = open_to_namei_flags(op->open_flag); - nd.intent.open.create_mode = op->mode; + nd->intent.open.file = filp; + nd->intent.open.flags = open_to_namei_flags(op->open_flag); + nd->intent.open.create_mode = op->mode; - error = path_init(dfd, pathname, flags | LOOKUP_PARENT, &nd, &base); + error = path_init(dfd, pathname, flags | LOOKUP_PARENT, nd, &base); if (unlikely(error)) goto out_filp; current->total_link_count = 0; - error = link_path_walk(pathname, &nd); + error = link_path_walk(pathname, nd); if (unlikely(error)) goto out_filp; - filp = do_last(&nd, &path, op, pathname); + filp = do_last(nd, &path, op, pathname); while (unlikely(!filp)) { /* trailing symlink */ struct path link = path; struct inode *linki = link.dentry->d_inode; void *cookie; - if (!(nd.flags & LOOKUP_FOLLOW) || count++ == 32) { - path_put_conditional(&path, &nd); - path_put(&nd.path); + if (!(nd->flags & LOOKUP_FOLLOW) || count++ == 32) { + path_put_conditional(&path, nd); + path_put(&nd->path); filp = ERR_PTR(-ELOOP); break; } @@ -2299,23 +2300,23 @@ static struct file *path_openat(int dfd, const char *pathname, * have to putname() it when we are done. Procfs-like symlinks * just set LAST_BIND. */ - nd.flags |= LOOKUP_PARENT; - nd.flags &= ~(LOOKUP_OPEN|LOOKUP_CREATE|LOOKUP_EXCL); - error = __do_follow_link(&link, &nd, &cookie); + nd->flags |= LOOKUP_PARENT; + nd->flags &= ~(LOOKUP_OPEN|LOOKUP_CREATE|LOOKUP_EXCL); + error = __do_follow_link(&link, nd, &cookie); if (unlikely(error)) filp = ERR_PTR(error); else - filp = do_last(&nd, &path, op, pathname); + filp = do_last(nd, &path, op, pathname); if (!IS_ERR(cookie) && linki->i_op->put_link) - linki->i_op->put_link(link.dentry, &nd, cookie); + linki->i_op->put_link(link.dentry, nd, cookie); path_put(&link); } out: - if (nd.root.mnt && !(nd.flags & LOOKUP_ROOT)) - path_put(&nd.root); + if (nd->root.mnt && !(nd->flags & LOOKUP_ROOT)) + path_put(&nd->root); if (base) fput(base); - release_open_intent(&nd); + release_open_intent(nd); return filp; out_filp: @@ -2326,16 +2327,39 @@ out_filp: struct file *do_filp_open(int dfd, const char *pathname, const struct open_flags *op, int flags) { + struct nameidata nd; struct file *filp; - filp = path_openat(dfd, pathname, op, flags | LOOKUP_RCU); + filp = path_openat(dfd, pathname, &nd, op, flags | LOOKUP_RCU); if (unlikely(filp == ERR_PTR(-ECHILD))) - filp = path_openat(dfd, pathname, op, flags); + filp = path_openat(dfd, pathname, &nd, op, flags); if (unlikely(filp == ERR_PTR(-ESTALE))) - filp = path_openat(dfd, pathname, op, flags | LOOKUP_REVAL); + filp = path_openat(dfd, pathname, &nd, op, flags | LOOKUP_REVAL); return filp; } +struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt, + const char *name, const struct open_flags *op, int flags) +{ + struct nameidata nd; + struct file *file; + + nd.root.mnt = mnt; + nd.root.dentry = dentry; + + flags |= LOOKUP_ROOT; + + if (dentry->d_inode->i_op->follow_link) + return ERR_PTR(-ELOOP); + + file = path_openat(-1, name, &nd, op, flags | LOOKUP_RCU); + if (unlikely(file == ERR_PTR(-ECHILD))) + file = path_openat(-1, name, &nd, op, flags); + if (unlikely(file == ERR_PTR(-ESTALE))) + file = path_openat(-1, name, &nd, op, flags | LOOKUP_REVAL); + return file; +} + /** * lookup_create - lookup a dentry, creating it if it doesn't exist * @nd: nameidata info diff --git a/fs/nfsctl.c b/fs/nfsctl.c index bf9cbd242ddd..124e8fcb0dd6 100644 --- a/fs/nfsctl.c +++ b/fs/nfsctl.c @@ -22,30 +22,17 @@ static struct file *do_open(char *name, int flags) { - struct nameidata nd; struct vfsmount *mnt; - int error; + struct file *file; mnt = do_kern_mount("nfsd", 0, "nfsd", NULL); if (IS_ERR(mnt)) return (struct file *)mnt; - error = vfs_path_lookup(mnt->mnt_root, mnt, name, 0, &nd); - mntput(mnt); /* drop do_kern_mount reference */ - if (error) - return ERR_PTR(error); - - if (flags == O_RDWR) - error = may_open(&nd.path, MAY_READ|MAY_WRITE, flags); - else - error = may_open(&nd.path, MAY_WRITE, flags); + file = file_open_root(mnt->mnt_root, mnt, name, flags); - if (!error) - return dentry_open(nd.path.dentry, nd.path.mnt, flags, - current_cred()); - - path_put(&nd.path); - return ERR_PTR(error); + mntput(mnt); /* drop do_kern_mount reference */ + return file; } static struct { diff --git a/fs/open.c b/fs/open.c index d05e18c60bae..48afc5c139d2 100644 --- a/fs/open.c +++ b/fs/open.c @@ -959,6 +959,20 @@ struct file *filp_open(const char *filename, int flags, int mode) } EXPORT_SYMBOL(filp_open); +struct file *file_open_root(struct dentry *dentry, struct vfsmount *mnt, + const char *filename, int flags) +{ + struct open_flags op; + int lookup = build_open_flags(flags, 0, &op); + if (flags & O_CREAT) + return ERR_PTR(-EINVAL); + if (!filename && (flags & O_DIRECTORY)) + if (!dentry->d_inode->i_op->lookup) + return ERR_PTR(-ENOTDIR); + return do_file_open_root(dentry, mnt, filename, &op, lookup); +} +EXPORT_SYMBOL(file_open_root); + long do_sys_open(int dfd, const char __user *filename, int flags, int mode) { struct open_flags op; diff --git a/include/linux/fs.h b/include/linux/fs.h index 9c75714f92c1..bf5c3c896072 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1990,6 +1990,8 @@ extern int do_fallocate(struct file *file, int mode, loff_t offset, extern long do_sys_open(int dfd, const char __user *filename, int flags, int mode); extern struct file *filp_open(const char *, int, int); +extern struct file *file_open_root(struct dentry *, struct vfsmount *, + const char *, int); extern struct file * dentry_open(struct dentry *, struct vfsmount *, int, const struct cred *); extern int filp_close(struct file *, fl_owner_t id); @@ -2205,8 +2207,6 @@ extern struct file *create_read_pipe(struct file *f, int flags); extern struct file *create_write_pipe(int flags); extern void free_write_pipe(struct file *); -extern int may_open(struct path *, int, int); - extern int kernel_read(struct file *, loff_t, char *, unsigned long); extern struct file * open_exec(const char *); diff --git a/kernel/sysctl_binary.c b/kernel/sysctl_binary.c index b875bedf7c9a..3b8e028b9601 100644 --- a/kernel/sysctl_binary.c +++ b/kernel/sysctl_binary.c @@ -1321,13 +1321,11 @@ static ssize_t binary_sysctl(const int *name, int nlen, void __user *oldval, size_t oldlen, void __user *newval, size_t newlen) { const struct bin_table *table = NULL; - struct nameidata nd; struct vfsmount *mnt; struct file *file; ssize_t result; char *pathname; int flags; - int acc_mode; pathname = sysctl_getname(name, nlen, &table); result = PTR_ERR(pathname); @@ -1337,28 +1335,17 @@ static ssize_t binary_sysctl(const int *name, int nlen, /* How should the sysctl be accessed? */ if (oldval && oldlen && newval && newlen) { flags = O_RDWR; - acc_mode = MAY_READ | MAY_WRITE; } else if (newval && newlen) { flags = O_WRONLY; - acc_mode = MAY_WRITE; } else if (oldval && oldlen) { flags = O_RDONLY; - acc_mode = MAY_READ; } else { result = 0; goto out_putname; } mnt = current->nsproxy->pid_ns->proc_mnt; - result = vfs_path_lookup(mnt->mnt_root, mnt, pathname, 0, &nd); - if (result) - goto out_putname; - - result = may_open(&nd.path, acc_mode, flags); - if (result) - goto out_putpath; - - file = dentry_open(nd.path.dentry, nd.path.mnt, flags, current_cred()); + file = file_open_root(mnt->mnt_root, mnt, pathname, flags); result = PTR_ERR(file); if (IS_ERR(file)) goto out_putname; @@ -1370,10 +1357,6 @@ out_putname: putname(pathname); out: return result; - -out_putpath: - path_put(&nd.path); - goto out_putname; }