diff options
Diffstat (limited to 'include/linux/namei.h')
| -rw-r--r-- | include/linux/namei.h | 249 |
1 files changed, 180 insertions, 69 deletions
diff --git a/include/linux/namei.h b/include/linux/namei.h index 5a5ff57ceed4..58600cf234bc 100644 --- a/include/linux/namei.h +++ b/include/linux/namei.h @@ -1,98 +1,209 @@ +/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _LINUX_NAMEI_H #define _LINUX_NAMEI_H -#include <linux/dcache.h> -#include <linux/errno.h> -#include <linux/linkage.h> +#include <linux/fs.h> +#include <linux/kernel.h> #include <linux/path.h> - -struct vfsmount; +#include <linux/fcntl.h> +#include <linux/errno.h> +#include <linux/fs_struct.h> enum { MAX_NESTED_LINKS = 8 }; -struct nameidata { - struct path path; - struct qstr last; - struct path root; - struct inode *inode; /* path.dentry.d_inode */ - unsigned int flags; - unsigned seq; - int last_type; - unsigned depth; - char *saved_names[MAX_NESTED_LINKS + 1]; -}; +#define MAXSYMLINKS 40 /* * Type of the last component on LOOKUP_PARENT */ -enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND}; - -/* - * The bitmask for a lookup event: - * - follow links at the end - * - require a directory - * - ending slashes ok even for nonexistent files - * - internal "there are more path components" flag - * - dentry cache is untrusted; force a real lookup - * - suppress terminal automount - */ -#define LOOKUP_FOLLOW 0x0001 -#define LOOKUP_DIRECTORY 0x0002 -#define LOOKUP_AUTOMOUNT 0x0004 - -#define LOOKUP_PARENT 0x0010 -#define LOOKUP_REVAL 0x0020 -#define LOOKUP_RCU 0x0040 - -/* - * Intent data - */ -#define LOOKUP_OPEN 0x0100 -#define LOOKUP_CREATE 0x0200 -#define LOOKUP_EXCL 0x0400 -#define LOOKUP_RENAME_TARGET 0x0800 - -#define LOOKUP_JUMPED 0x1000 -#define LOOKUP_ROOT 0x2000 -#define LOOKUP_EMPTY 0x4000 +enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT}; + +/* pathwalk mode */ +#define LOOKUP_FOLLOW BIT(0) /* follow links at the end */ +#define LOOKUP_DIRECTORY BIT(1) /* require a directory */ +#define LOOKUP_AUTOMOUNT BIT(2) /* force terminal automount */ +#define LOOKUP_EMPTY BIT(3) /* accept empty path [user_... only] */ +#define LOOKUP_LINKAT_EMPTY BIT(4) /* Linkat request with empty path. */ +#define LOOKUP_DOWN BIT(5) /* follow mounts in the starting point */ +#define LOOKUP_MOUNTPOINT BIT(6) /* follow mounts in the end */ +#define LOOKUP_REVAL BIT(7) /* tell ->d_revalidate() to trust no cache */ +#define LOOKUP_RCU BIT(8) /* RCU pathwalk mode; semi-internal */ +#define LOOKUP_CACHED BIT(9) /* Only do cached lookup */ +#define LOOKUP_PARENT BIT(10) /* Looking up final parent in path */ +/* 5 spare bits for pathwalk */ + +/* These tell filesystem methods that we are dealing with the final component... */ +#define LOOKUP_OPEN BIT(16) /* ... in open */ +#define LOOKUP_CREATE BIT(17) /* ... in object creation */ +#define LOOKUP_EXCL BIT(18) /* ... in target must not exist */ +#define LOOKUP_RENAME_TARGET BIT(19) /* ... in destination of rename() */ + +/* 4 spare bits for intent */ + +/* Scoping flags for lookup. */ +#define LOOKUP_NO_SYMLINKS BIT(24) /* No symlink crossing. */ +#define LOOKUP_NO_MAGICLINKS BIT(25) /* No nd_jump_link() crossing. */ +#define LOOKUP_NO_XDEV BIT(26) /* No mountpoint crossing. */ +#define LOOKUP_BENEATH BIT(27) /* No escaping from starting point. */ +#define LOOKUP_IN_ROOT BIT(28) /* Treat dirfd as fs root. */ +/* LOOKUP_* flags which do scope-related checks based on the dirfd. */ +#define LOOKUP_IS_SCOPED (LOOKUP_BENEATH | LOOKUP_IN_ROOT) +/* 3 spare bits for scoping */ + +extern int path_pts(struct path *path); extern int user_path_at(int, const char __user *, unsigned, struct path *); -extern int user_path_at_empty(int, const char __user *, unsigned, struct path *, int *empty); - -#define user_path(name, path) user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW, path) -#define user_lpath(name, path) user_path_at(AT_FDCWD, name, 0, path) -#define user_path_dir(name, path) \ - user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, path) +struct dentry *lookup_one_qstr_excl(const struct qstr *name, + struct dentry *base, + unsigned int flags); extern int kern_path(const char *, unsigned, struct path *); +struct dentry *kern_path_parent(const char *name, struct path *parent); + +extern struct dentry *start_creating_path(int, const char *, struct path *, unsigned int); +extern struct dentry *start_creating_user_path(int, const char __user *, struct path *, unsigned int); +extern void end_creating_path(const struct path *, struct dentry *); +extern struct dentry *start_removing_path(const char *, struct path *); +extern struct dentry *start_removing_user_path_at(int , const char __user *, struct path *); +static inline void end_removing_path(const struct path *path , struct dentry *dentry) +{ + end_creating_path(path, dentry); +} +int vfs_path_parent_lookup(struct filename *filename, unsigned int flags, + struct path *parent, struct qstr *last, int *type, + const struct path *root); +int vfs_path_lookup(struct dentry *, struct vfsmount *, const char *, + unsigned int, struct path *); + +extern struct dentry *try_lookup_noperm(struct qstr *, struct dentry *); +extern struct dentry *lookup_noperm(struct qstr *, struct dentry *); +extern struct dentry *lookup_noperm_unlocked(struct qstr *, struct dentry *); +extern struct dentry *lookup_noperm_positive_unlocked(struct qstr *, struct dentry *); +struct dentry *lookup_one(struct mnt_idmap *, struct qstr *, struct dentry *); +struct dentry *lookup_one_unlocked(struct mnt_idmap *idmap, + struct qstr *name, struct dentry *base); +struct dentry *lookup_one_positive_unlocked(struct mnt_idmap *idmap, + struct qstr *name, + struct dentry *base); +struct dentry *lookup_one_positive_killable(struct mnt_idmap *idmap, + struct qstr *name, + struct dentry *base); + +struct dentry *start_creating(struct mnt_idmap *idmap, struct dentry *parent, + struct qstr *name); +struct dentry *start_removing(struct mnt_idmap *idmap, struct dentry *parent, + struct qstr *name); +struct dentry *start_creating_killable(struct mnt_idmap *idmap, + struct dentry *parent, + struct qstr *name); +struct dentry *start_removing_killable(struct mnt_idmap *idmap, + struct dentry *parent, + struct qstr *name); +struct dentry *start_creating_noperm(struct dentry *parent, struct qstr *name); +struct dentry *start_removing_noperm(struct dentry *parent, struct qstr *name); +struct dentry *start_creating_dentry(struct dentry *parent, + struct dentry *child); +struct dentry *start_removing_dentry(struct dentry *parent, + struct dentry *child); + +/* end_creating - finish action started with start_creating + * @child: dentry returned by start_creating() or vfs_mkdir() + * + * Unlock and release the child. This can be called after + * start_creating() whether that function succeeded or not, + * but it is not needed on failure. + * + * If vfs_mkdir() was called then the value returned from that function + * should be given for @child rather than the original dentry, as vfs_mkdir() + * may have provided a new dentry. + * + * + * If vfs_mkdir() was not called, then @child will be a valid dentry and + * @parent will be ignored. + */ +static inline void end_creating(struct dentry *child) +{ + end_dirop(child); +} -extern struct dentry *kern_path_create(int, const char *, struct path *, unsigned int); -extern struct dentry *user_path_create(int, const char __user *, struct path *, unsigned int); -extern void done_path_create(struct path *, struct dentry *); -extern struct dentry *kern_path_locked(const char *, struct path *); -extern int vfs_path_lookup(struct dentry *, struct vfsmount *, - const char *, unsigned int, struct path *); +/* end_creating_keep - finish action started with start_creating() and return result + * @child: dentry returned by start_creating() or vfs_mkdir() + * + * Unlock and return the child. This can be called after + * start_creating() whether that function succeeded or not, + * but it is not needed on failure. + * + * If vfs_mkdir() was called then the value returned from that function + * should be given for @child rather than the original dentry, as vfs_mkdir() + * may have provided a new dentry. + * + * Returns: @child, which may be a dentry or an error. + * + */ +static inline struct dentry *end_creating_keep(struct dentry *child) +{ + if (!IS_ERR(child)) + dget(child); + end_dirop(child); + return child; +} -extern struct dentry *lookup_one_len(const char *, struct dentry *, int); +/** + * end_removing - finish action started with start_removing + * @child: dentry returned by start_removing() + * @parent: dentry given to start_removing() + * + * Unlock and release the child. + * + * This is identical to end_dirop(). It can be passed the result of + * start_removing() whether that was successful or not, but it not needed + * if start_removing() failed. + */ +static inline void end_removing(struct dentry *child) +{ + end_dirop(child); +} extern int follow_down_one(struct path *); -extern int follow_down(struct path *); +extern int follow_down(struct path *path, unsigned int flags); extern int follow_up(struct path *); extern struct dentry *lock_rename(struct dentry *, struct dentry *); +extern struct dentry *lock_rename_child(struct dentry *, struct dentry *); extern void unlock_rename(struct dentry *, struct dentry *); +int start_renaming(struct renamedata *rd, int lookup_flags, + struct qstr *old_last, struct qstr *new_last); +int start_renaming_dentry(struct renamedata *rd, int lookup_flags, + struct dentry *old_dentry, struct qstr *new_last); +int start_renaming_two_dentries(struct renamedata *rd, + struct dentry *old_dentry, struct dentry *new_dentry); +void end_renaming(struct renamedata *rd); -extern void nd_jump_link(struct nameidata *nd, struct path *path); - -static inline void nd_set_link(struct nameidata *nd, char *path) +/** + * mode_strip_umask - handle vfs umask stripping + * @dir: parent directory of the new inode + * @mode: mode of the new inode to be created in @dir + * + * In most filesystems, umask stripping depends on whether or not the + * filesystem supports POSIX ACLs. If the filesystem doesn't support it umask + * stripping is done directly in here. If the filesystem does support POSIX + * ACLs umask stripping is deferred until the filesystem calls + * posix_acl_create(). + * + * Some filesystems (like NFSv4) also want to avoid umask stripping by the + * VFS, but don't support POSIX ACLs. Those filesystems can set SB_I_NOUMASK + * to get this effect without declaring that they support POSIX ACLs. + * + * Returns: mode + */ +static inline umode_t __must_check mode_strip_umask(const struct inode *dir, umode_t mode) { - nd->saved_names[nd->depth] = path; + if (!IS_POSIXACL(dir) && !(dir->i_sb->s_iflags & SB_I_NOUMASK)) + mode &= ~current_umask(); + return mode; } -static inline char *nd_get_link(struct nameidata *nd) -{ - return nd->saved_names[nd->depth]; -} +extern int __must_check nd_jump_link(const struct path *path); static inline void nd_terminate_link(void *name, size_t len, size_t maxlen) { @@ -112,7 +223,7 @@ static inline void nd_terminate_link(void *name, size_t len, size_t maxlen) static inline bool retry_estale(const long error, const unsigned int flags) { - return error == -ESTALE && !(flags & LOOKUP_REVAL); + return unlikely(error == -ESTALE && !(flags & LOOKUP_REVAL)); } #endif /* _LINUX_NAMEI_H */ |