include/linux/namei.h

   1 #ifndef _LINUX_NAMEI_H
   2 #define _LINUX_NAMEI_H
   3
   4 #include <linux/dcache.h>
   5 #include <linux/errno.h>
   6 #include <linux/linkage.h>
   7 #include <linux/path.h>
   8
   9 struct vfsmount;
  10 struct nameidata;
  11
  12 enum { MAX_NESTED_LINKS = 8 };
  13
  14 /*
  15  * Type of the last component on LOOKUP_PARENT
  16  */
  17 enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND};
  18
  19 /*
  20  * The bitmask for a lookup event:
  21  *  - follow links at the end
  22  *  - require a directory
  23  *  - ending slashes ok even for nonexistent files
  24  *  - internal "there are more path components" flag
  25  *  - dentry cache is untrusted; force a real lookup
  26  *  - suppress terminal automount
  27  */
  28 #define LOOKUP_FOLLOW           0x0001
  29 #define LOOKUP_DIRECTORY        0x0002
  30 #define LOOKUP_AUTOMOUNT        0x0004
  31
  32 #define LOOKUP_PARENT           0x0010
  33 #define LOOKUP_REVAL            0x0020
  34 #define LOOKUP_RCU              0x0040
  35
  36 /*
  37  * Intent data
  38  */
  39 #define LOOKUP_OPEN             0x0100
  40 #define LOOKUP_CREATE           0x0200
  41 #define LOOKUP_EXCL             0x0400
  42 #define LOOKUP_RENAME_TARGET    0x0800
  43
  44 #define LOOKUP_JUMPED           0x1000
  45 #define LOOKUP_ROOT             0x2000
  46 #define LOOKUP_EMPTY            0x4000
  47
  48 extern int user_path_at(int, const char __user *, unsigned, struct path *);
  49 extern int user_path_at_empty(int, const char __user *, unsigned, struct path *, int *empty);
  50
  51 #define user_path(name, path) user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW, path)
  52 #define user_lpath(name, path) user_path_at(AT_FDCWD, name, 0, path)
  53 #define user_path_dir(name, path) \
  54         user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, path)
  55
  56 extern int kern_path(const char *, unsigned, struct path *);
  57
  58 extern struct dentry *kern_path_create(int, const char *, struct path *, unsigned int);
  59 extern struct dentry *user_path_create(int, const char __user *, struct path *, unsigned int);
  60 extern void done_path_create(struct path *, struct dentry *);
  61 extern struct dentry *kern_path_locked(const char *, struct path *);
  62 extern int kern_path_mountpoint(int, const char *, struct path *, unsigned int);
  63
  64 extern struct dentry *lookup_one_len(const char *, struct dentry *, int);
  65
  66 extern int follow_down_one(struct path *);
  67 extern int follow_down(struct path *);
  68 extern int follow_up(struct path *);
  69
  70 extern struct dentry *lock_rename(struct dentry *, struct dentry *);
  71 extern void unlock_rename(struct dentry *, struct dentry *);
  72
  73 extern void nd_jump_link(struct nameidata *nd, struct path *path);
  74 extern void nd_set_link(struct nameidata *nd, char *path);
  75 extern char *nd_get_link(struct nameidata *nd);
  76
  77 static inline void nd_terminate_link(void *name, size_t len, size_t maxlen)
  78 {
  79         ((char *) name)[min(len, maxlen)] = '\0';
  80 }
  81
  82 /**
  83  * retry_estale - determine whether the caller should retry an operation
  84  * @error: the error that would currently be returned
  85  * @flags: flags being used for next lookup attempt
  86  *
  87  * Check to see if the error code was -ESTALE, and then determine whether
  88  * to retry the call based on whether "flags" already has LOOKUP_REVAL set.
  89  *
  90  * Returns true if the caller should try the operation again.
  91  */
  92 static inline bool
  93 retry_estale(const long error, const unsigned int flags)
  94 {
  95         return error == -ESTALE && !(flags & LOOKUP_REVAL);
  96 }
  97
  98 #endif /* _LINUX_NAMEI_H */