diff options
Diffstat (limited to 'include/linux/namei.h')
| -rw-r--r-- | include/linux/namei.h | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/include/linux/namei.h b/include/linux/namei.h new file mode 100644 index 000000000..5c0149603 --- /dev/null +++ b/include/linux/namei.h @@ -0,0 +1,116 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_NAMEI_H +#define _LINUX_NAMEI_H + +#include <linux/fs.h> +#include <linux/kernel.h> +#include <linux/path.h> +#include <linux/fcntl.h> +#include <linux/errno.h> + +enum { MAX_NESTED_LINKS = 8 }; + +#define MAXSYMLINKS 40 + +/* + * Type of the last component on LOOKUP_PARENT + */ +enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT}; + +/* pathwalk mode */ +#define LOOKUP_FOLLOW 0x0001 /* follow links at the end */ +#define LOOKUP_DIRECTORY 0x0002 /* require a directory */ +#define LOOKUP_AUTOMOUNT 0x0004 /* force terminal automount */ +#define LOOKUP_EMPTY 0x4000 /* accept empty path [user_... only] */ +#define LOOKUP_DOWN 0x8000 /* follow mounts in the starting point */ +#define LOOKUP_MOUNTPOINT 0x0080 /* follow mounts in the end */ + +#define LOOKUP_REVAL 0x0020 /* tell ->d_revalidate() to trust no cache */ +#define LOOKUP_RCU 0x0040 /* RCU pathwalk mode; semi-internal */ + +/* These tell filesystem methods that we are dealing with the final component... */ +#define LOOKUP_OPEN 0x0100 /* ... in open */ +#define LOOKUP_CREATE 0x0200 /* ... in object creation */ +#define LOOKUP_EXCL 0x0400 /* ... in exclusive creation */ +#define LOOKUP_RENAME_TARGET 0x0800 /* ... in destination of rename() */ + +/* internal use only */ +#define LOOKUP_PARENT 0x0010 + +/* Scoping flags for lookup. */ +#define LOOKUP_NO_SYMLINKS 0x010000 /* No symlink crossing. */ +#define LOOKUP_NO_MAGICLINKS 0x020000 /* No nd_jump_link() crossing. */ +#define LOOKUP_NO_XDEV 0x040000 /* No mountpoint crossing. */ +#define LOOKUP_BENEATH 0x080000 /* No escaping from starting point. */ +#define LOOKUP_IN_ROOT 0x100000 /* Treat dirfd as fs root. */ +#define LOOKUP_CACHED 0x200000 /* Only do cached lookup */ +/* LOOKUP_* flags which do scope-related checks based on the dirfd. */ +#define LOOKUP_IS_SCOPED (LOOKUP_BENEATH | LOOKUP_IN_ROOT) + +extern int path_pts(struct path *path); + +extern int user_path_at_empty(int, const char __user *, unsigned, struct path *, int *empty); + +static inline int user_path_at(int dfd, const char __user *name, unsigned flags, + struct path *path) +{ + return user_path_at_empty(dfd, name, flags, path, NULL); +} + +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 *); + +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 *); +int vfs_path_parent_lookup(struct filename *filename, unsigned int flags, + struct path *parent, struct qstr *last, int *type, + const struct path *root); + +extern struct dentry *try_lookup_one_len(const char *, struct dentry *, int); +extern struct dentry *lookup_one_len(const char *, struct dentry *, int); +extern struct dentry *lookup_one_len_unlocked(const char *, struct dentry *, int); +extern struct dentry *lookup_positive_unlocked(const char *, struct dentry *, int); +struct dentry *lookup_one(struct user_namespace *, const char *, struct dentry *, int); +struct dentry *lookup_one_unlocked(struct user_namespace *mnt_userns, + const char *name, struct dentry *base, + int len); +struct dentry *lookup_one_positive_unlocked(struct user_namespace *mnt_userns, + const char *name, + struct dentry *base, int len); + +extern int follow_down_one(struct path *); +extern int follow_down(struct path *); +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 *); + +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) +{ + ((char *) name)[min(len, maxlen)] = '\0'; +} + +/** + * retry_estale - determine whether the caller should retry an operation + * @error: the error that would currently be returned + * @flags: flags being used for next lookup attempt + * + * Check to see if the error code was -ESTALE, and then determine whether + * to retry the call based on whether "flags" already has LOOKUP_REVAL set. + * + * Returns true if the caller should try the operation again. + */ +static inline bool +retry_estale(const long error, const unsigned int flags) +{ + return error == -ESTALE && !(flags & LOOKUP_REVAL); +} + +#endif /* _LINUX_NAMEI_H */ |