mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-15 16:53:54 +08:00
b4c0353693
->last_type values are set in 3 places: path_init() (sets to LAST_ROOT), link_path_walk (LAST_NORM/DOT/DOTDOT) and pick_link (LAST_BIND). The are checked in walk_component(), lookup_last() and do_last(). They also get copied to the caller by filename_parentat(). In the last 3 cases the value is what we had at the return from link_path_walk(). In case of walk_component() it's either directly downstream from assignment in link_path_walk() or, when called by lookup_last(), the value we have at the return from link_path_walk(). The value at the entry into link_path_walk() can survive to return only if the pathname contains nothing but slashes. Note that pick_link() never returns such - pure jumps are handled directly. So for the calls of link_path_walk() for trailing symlinks it does not matter what value had been there at the entry; the value at the return won't depend upon it. There are 3 call chains that might have pick_link() storing LAST_BIND: 1) pick_link() from step_into() from walk_component() from link_path_walk(). In that case we will either be parsing the next component immediately after return into link_path_walk(), which will overwrite the ->last_type before anyone has a chance to look at it, or we'll fail, in which case nobody will be looking at ->last_type at all. 2) pick_link() from step_into() from walk_component() from lookup_last(). The value is never looked at due to the above; it won't affect the value seen at return from any link_path_walk(). 3) pick_link() from step_into() from do_last(). Ditto. In other words, assignemnt in pick_link() is pointless, and so is LAST_BIND itself; nothing ever looks at that value. Kill it off. And make link_path_walk() _always_ assign ->last_type - in the only case when the value at the entry might survive to the return that value is always LAST_ROOT, inherited from path_init(). Move that assignment from path_init() into the beginning of link_path_walk(), to consolidate the things. Historical note: LAST_BIND used to be used for the kludge with trailing pure jump symlinks (extra iteration through the top-level loop). No point keeping it anymore... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
105 lines
3.8 KiB
C
105 lines
3.8 KiB
C
/* 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
|
|
#define LOOKUP_JUMPED 0x1000
|
|
#define LOOKUP_ROOT 0x2000
|
|
#define LOOKUP_ROOT_GRABBED 0x0008
|
|
|
|
/* 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. */
|
|
/* 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);
|
|
}
|
|
|
|
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 *);
|
|
|
|
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);
|
|
|
|
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 void unlock_rename(struct dentry *, struct dentry *);
|
|
|
|
extern int __must_check nd_jump_link(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 */
|