about summary refs log tree commit diff
path: root/sysdeps/unix/sysv/linux/fxstatat.c
blob: 89638ba80589ae244eae585aca1530ddfbe28587 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
/* Copyright (C) 2005, 2006, 2007, 2009 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

/* Ho hum, if fxstatat == fxstatat64 we must get rid of the prototype or gcc
   will complain since they don't strictly match.  */
#define __fxstatat64 __fxstatat64_disable

#include <errno.h>
#include <fcntl.h>
#include <stddef.h>
#include <stdio.h>
#include <sys/stat.h>
#include <kernel_stat.h>

#include <sysdep.h>
#include <sys/syscall.h>
#include <bp-checks.h>
#include <kernel-features.h>

#include <xstatconv.h>

/* Get information about the file NAME in BUF.  */
int
__fxstatat (int vers, int fd, const char *file, struct stat *st, int flag)
{
  int result;
  INTERNAL_SYSCALL_DECL (err);
#ifdef STAT_IS_KERNEL_STAT
# define kst (*st)
#else
  struct kernel_stat kst;
#endif

#ifdef __NR_newfstatat
# ifndef __ASSUME_ATFCTS
  if (__have_atfcts >= 0)
# endif
    {
      result = INTERNAL_SYSCALL (newfstatat, err, 4, fd, file, &kst, flag);
# ifndef __ASSUME_ATFCTS
      if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (result, err), 1)
	  && INTERNAL_SYSCALL_ERRNO (result, err) == ENOSYS)
	__have_atfcts = -1;
      else
# endif
	if (!__builtin_expect (INTERNAL_SYSCALL_ERROR_P (result, err), 1))
	  {
#ifdef STAT_IS_KERNEL_STAT
	    return 0;
#else
	    return __xstat_conv (vers, &kst, st);
#endif
	  }
	else
	  {
	    __set_errno (INTERNAL_SYSCALL_ERRNO (result, err));
	    return -1;
	  }
    }
#endif

  if (flag & ~AT_SYMLINK_NOFOLLOW)
    {
      __set_errno (EINVAL);
      return -1;
    }

  char *buf = NULL;

  if (fd != AT_FDCWD && file[0] != '/')
    {
      size_t filelen = strlen (file);
      if (__builtin_expect (filelen == 0, 0))
	{
	  __set_errno (ENOENT);
	  return -1;
	}

      static const char procfd[] = "/proc/self/fd/%d/%s";
      /* Buffer for the path name we are going to use.  It consists of
	 - the string /proc/self/fd/
	 - the file descriptor number
	 - the file name provided.
	 The final NUL is included in the sizeof.   A bit of overhead
	 due to the format elements compensates for possible negative
	 numbers.  */
      size_t buflen = sizeof (procfd) + sizeof (int) * 3 + filelen;
      buf = alloca (buflen);

      __snprintf (buf, buflen, procfd, fd, file);
      file = buf;
    }

  if (vers == _STAT_VER_KERNEL)
    {
      if (flag & AT_SYMLINK_NOFOLLOW)
	result = INTERNAL_SYSCALL (lstat, err, 2, CHECK_STRING (file),
				   CHECK_1 ((struct kernel_stat *) st));
      else
	result = INTERNAL_SYSCALL (stat, err, 2, CHECK_STRING (file),
				   CHECK_1 ((struct kernel_stat *) st));

      if (__builtin_expect (!INTERNAL_SYSCALL_ERROR_P (result, err), 1))
	return result;
    }
#ifdef STAT_IS_KERNEL_STAT
  else
    {
      __set_errno (EINVAL);
      return -1;
    }
#else
  if (flag & AT_SYMLINK_NOFOLLOW)
    result = INTERNAL_SYSCALL (lstat, err, 2, CHECK_STRING (file),
			       __ptrvalue (&kst));
  else
    result = INTERNAL_SYSCALL (stat, err, 2, CHECK_STRING (file),
			       __ptrvalue (&kst));

  if (__builtin_expect (!INTERNAL_SYSCALL_ERROR_P (result, err), 1))
    return __xstat_conv (vers, &kst, st);
#endif

  __atfct_seterrno (INTERNAL_SYSCALL_ERRNO (result, err), fd, buf);

  return -1;
}
libc_hidden_def (__fxstatat)
#ifdef XSTAT_IS_XSTAT64
# undef __fxstatat64
strong_alias (__fxstatat, __fxstatat64);
libc_hidden_def (__fxstatat64)
#endif