namei.h

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#ifndef _LINUX_NAMEI_H
#define _LINUX_NAMEI_H

#include <linux/dcache.h>
#include <linux/linkage.h>
#include <linux/path.h>

struct vfsmount;

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];
};

/*
 * 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

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)

extern int kern_path(const char *, unsigned, struct path *);

extern struct dentry *kern_path_create(int, const char *, struct path *, int);
extern struct dentry *user_path_create(int, const char __user *, struct path *, 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 *);

extern struct dentry *lookup_one_len(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 void nd_jump_link(struct nameidata *nd, struct path *path);

static inline void nd_set_link(struct nameidata *nd, char *path)
{
    nd->saved_names[nd->depth] = path;
}

static inline char *nd_get_link(struct nameidata *nd)
{
    return nd->saved_names[nd->depth];
}

static inline void nd_terminate_link(void *name, size_t len, size_t maxlen)
{
    ((char *) name)[min(len, maxlen)] = '\0';
}

#endif /* _LINUX_NAMEI_H */