1/* provide a replacement openat function
2   Copyright (C) 2004, 2005, 2006 Free Software Foundation, Inc.
3
4   This program is free software; you can redistribute it and/or modify
5   it under the terms of the GNU General Public License as published by
6   the Free Software Foundation; either version 2, or (at your option)
7   any later version.
8
9   This program is distributed in the hope that it will be useful,
10   but WITHOUT ANY WARRANTY; without even the implied warranty of
11   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12   GNU General Public License for more details.
13
14   You should have received a copy of the GNU General Public License
15   along with this program; if not, write to the Free Software Foundation,
16   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
17
18/* written by Jim Meyering */
19
20#include <fcntl.h>
21
22#include <sys/types.h>
23#include <sys/stat.h>
24#include <dirent.h>
25#include <unistd.h>
26#include <stdbool.h>
27
28#ifndef __attribute__
29# if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 8) || __STRICT_ANSI__
30#  define __attribute__(x) /* empty */
31# endif
32#endif
33
34#ifndef ATTRIBUTE_NORETURN
35# define ATTRIBUTE_NORETURN __attribute__ ((__noreturn__))
36#endif
37
38/* Work around a bug in Solaris 9 and 10: AT_FDCWD is positive.  Its
39   value exceeds INT_MAX, so its use as an int doesn't conform to the
40   C standard, and GCC and Sun C complain in some cases.  If the bug
41   is present, undef AT_FDCWD here, so it can be redefined below.  */
42#if 0 < AT_FDCWD && AT_FDCWD == 0xffd19553
43# undef AT_FDCWD
44#endif
45
46/* Use the same bit pattern as Solaris 9, but with the proper
47   signedness.  The bit pattern is important, in case this actually is
48   Solaris with the above workaround.  */
49#ifndef AT_FDCWD
50# define AT_FDCWD (-3041965)
51#endif
52
53/* Use the same values as Solaris 9.  This shouldn't matter, but
54   there's no real reason to differ.  */
55#ifndef AT_SYMLINK_NOFOLLOW
56# define AT_SYMLINK_NOFOLLOW 4096
57# define AT_REMOVEDIR 1
58#endif
59
60#ifdef __OPENAT_PREFIX
61
62# undef openat
63# define __OPENAT_CONCAT(x, y) x ## y
64# define __OPENAT_XCONCAT(x, y) __OPENAT_CONCAT (x, y)
65# define __OPENAT_ID(y) __OPENAT_XCONCAT (__OPENAT_PREFIX, y)
66# define openat __OPENAT_ID (openat)
67int openat (int fd, char const *file, int flags, /* mode_t mode */ ...);
68int openat_permissive (int fd, char const *file, int flags, mode_t mode,
69		       int *cwd_errno);
70# if ! HAVE_FDOPENDIR
71#  define fdopendir __OPENAT_ID (fdopendir)
72# endif
73DIR *fdopendir (int fd);
74# define fstatat __OPENAT_ID (fstatat)
75int fstatat (int fd, char const *file, struct stat *st, int flag);
76# define unlinkat __OPENAT_ID (unlinkat)
77int unlinkat (int fd, char const *file, int flag);
78bool openat_needs_fchdir (void);
79
80#else
81
82# define openat_permissive(Fd, File, Flags, Mode, Cwd_errno) \
83    openat (Fd, File, Flags, Mode)
84# define openat_needs_fchdir() false
85
86#endif
87
88#if HAVE_OPENAT && ! LSTAT_FOLLOWS_SLASHED_SYMLINK
89int rpl_fstatat (int fd, char const *file, struct stat *st, int flag);
90# if !COMPILING_FSTATAT
91#  undef fstatat
92#  define fstatat rpl_fstatat
93# endif
94#endif
95
96int mkdirat (int fd, char const *file, mode_t mode);
97void openat_restore_fail (int) ATTRIBUTE_NORETURN;
98void openat_save_fail (int) ATTRIBUTE_NORETURN;
99int fchmodat (int fd, char const *file, mode_t mode, int flag);
100int fchownat (int fd, char const *file, uid_t owner, gid_t group, int flag);
101
102/* Using these function names makes application code
103   slightly more readable than it would be with
104   fchownat (..., 0) or fchownat (..., AT_SYMLINK_NOFOLLOW).  */
105static inline int
106chownat (int fd, char const *file, uid_t owner, gid_t group)
107{
108  return fchownat (fd, file, owner, group, 0);
109}
110
111static inline int
112lchownat (int fd, char const *file, uid_t owner, gid_t group)
113{
114  return fchownat (fd, file, owner, group, AT_SYMLINK_NOFOLLOW);
115}
116
117static inline int
118chmodat (int fd, char const *file, mode_t mode)
119{
120  return fchmodat (fd, file, mode, 0);
121}
122
123static inline int
124lchmodat (int fd, char const *file, mode_t mode)
125{
126  return fchmodat (fd, file, mode, AT_SYMLINK_NOFOLLOW);
127}
128