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/* 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>
#include <linux/fs_struct.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 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 *);
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);
}
/* 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;
}
/**
* 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 *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);
/**
* 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)
{
if (!IS_POSIXACL(dir) && !(dir->i_sb->s_iflags & SB_I_NOUMASK))
mode &= ~current_umask();
return mode;
}
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 unlikely(error == -ESTALE && !(flags & LOOKUP_REVAL));
}
#endif /* _LINUX_NAMEI_H */
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