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1fa1e7f615
Since the commit below which added O_PATH support to the *at() calls, the
error return for readlink/readlinkat for the empty pathname has switched
from ENOENT to EINVAL:
commit 65cfc67223
Author: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun Mar 13 15:56:26 2011 -0400
readlinkat(), fchownat() and fstatat() with empty relative pathnames
This is both unexpected for userspace and makes readlink/readlinkat
inconsistant with all other interfaces; and inconsistant with our stated
return for these pathnames.
As the readlinkat call does not have a flags parameter we cannot use the
AT_EMPTY_PATH approach used in the other calls. Therefore expose whether
the original path is infact entry via a new user_path_at_empty() path
lookup function. Use this to determine whether to default to EINVAL or
ENOENT for failures.
Addresses http://bugs.launchpad.net/bugs/817187
[akpm@linux-foundation.org: remove unused getname_flags()]
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <stable@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
112 lines
3 KiB
C
112 lines
3 KiB
C
#ifndef _LINUX_NAMEI_H
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#define _LINUX_NAMEI_H
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#include <linux/dcache.h>
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#include <linux/linkage.h>
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#include <linux/path.h>
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struct vfsmount;
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struct open_intent {
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int flags;
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int create_mode;
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struct file *file;
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};
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enum { MAX_NESTED_LINKS = 8 };
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struct nameidata {
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struct path path;
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struct qstr last;
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struct path root;
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struct inode *inode; /* path.dentry.d_inode */
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unsigned int flags;
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unsigned seq;
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int last_type;
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unsigned depth;
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char *saved_names[MAX_NESTED_LINKS + 1];
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/* Intent data */
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union {
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struct open_intent open;
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} intent;
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};
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/*
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* Type of the last component on LOOKUP_PARENT
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*/
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enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND};
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/*
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* The bitmask for a lookup event:
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* - follow links at the end
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* - require a directory
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* - ending slashes ok even for nonexistent files
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* - internal "there are more path components" flag
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* - dentry cache is untrusted; force a real lookup
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* - suppress terminal automount
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*/
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#define LOOKUP_FOLLOW 0x0001
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#define LOOKUP_DIRECTORY 0x0002
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#define LOOKUP_AUTOMOUNT 0x0004
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#define LOOKUP_PARENT 0x0010
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#define LOOKUP_REVAL 0x0020
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#define LOOKUP_RCU 0x0040
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/*
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* Intent data
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*/
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#define LOOKUP_OPEN 0x0100
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#define LOOKUP_CREATE 0x0200
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#define LOOKUP_EXCL 0x0400
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#define LOOKUP_RENAME_TARGET 0x0800
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#define LOOKUP_JUMPED 0x1000
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#define LOOKUP_ROOT 0x2000
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#define LOOKUP_EMPTY 0x4000
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extern int user_path_at(int, const char __user *, unsigned, struct path *);
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extern int user_path_at_empty(int, const char __user *, unsigned, struct path *, int *empty);
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#define user_path(name, path) user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW, path)
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#define user_lpath(name, path) user_path_at(AT_FDCWD, name, 0, path)
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#define user_path_dir(name, path) \
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user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, path)
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extern int kern_path(const char *, unsigned, struct path *);
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extern struct dentry *kern_path_create(int, const char *, struct path *, int);
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extern struct dentry *user_path_create(int, const char __user *, struct path *, int);
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extern int kern_path_parent(const char *, struct nameidata *);
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extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
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const char *, unsigned int, struct path *);
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extern struct file *lookup_instantiate_filp(struct nameidata *nd, struct dentry *dentry,
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int (*open)(struct inode *, struct file *));
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extern struct dentry *lookup_one_len(const char *, struct dentry *, int);
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extern int follow_down_one(struct path *);
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extern int follow_down(struct path *);
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extern int follow_up(struct path *);
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extern struct dentry *lock_rename(struct dentry *, struct dentry *);
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extern void unlock_rename(struct dentry *, struct dentry *);
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static inline void nd_set_link(struct nameidata *nd, char *path)
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{
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nd->saved_names[nd->depth] = path;
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}
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static inline char *nd_get_link(struct nameidata *nd)
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{
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return nd->saved_names[nd->depth];
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}
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static inline void nd_terminate_link(void *name, size_t len, size_t maxlen)
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{
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((char *) name)[min(len, maxlen)] = '\0';
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}
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#endif /* _LINUX_NAMEI_H */
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