sysdeps/unix/sysv/linux/alpha/fxstatat.c

   1 /* Copyright (C) 2005, 2006, 2009 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library 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 GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library.  If not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #define __fxstatat64 __fxstatat64_disable
  19
  20 #include <errno.h>
  21 #include <fcntl.h>
  22 #include <stddef.h>
  23 #include <stdio.h>
  24 #include <sys/stat.h>
  25 #include <kernel_stat.h>
  26 #include <sysdep.h>
  27 #include <sys/syscall.h>
  28 #include <xstatconv.h>
  29
  30 #undef __fxstatat64
  31
  32 #ifdef __ASSUME_ATFCTS
  33 # define __have_atfcts 1
  34 #endif
  35 #ifdef __ASSUME_STAT64_SYSCALL
  36 # define __libc_missing_axp_stat64 0
  37 #endif
  38
  39 /* Get information about the file NAME in BUF.  */
  40 int
  41 __fxstatat (int vers, int fd, const char *file, struct stat *st, int flag)
  42 {
  43   INTERNAL_SYSCALL_DECL (err);
  44   int result, errno_out;
  45
  46   /* ??? The __fxstatat entry point is new enough that it must be using
  47      vers == _STAT_VER_KERNEL64.  For the benefit of dl-fxstatat64.c, we
  48      cannot actually check this, lest the compiler not optimize the rest
  49      of the function away.  */
  50
  51 #ifdef __NR_fstatat64
  52   if (__have_atfcts >= 0)
  53     {
  54       result = INTERNAL_SYSCALL (fstatat64, err, 4, fd, file, st, flag);
  55       if (__builtin_expect (!INTERNAL_SYSCALL_ERROR_P (result, err), 1))
  56         return result;
  57       errno_out = INTERNAL_SYSCALL_ERRNO (result, err);
  58 #ifndef __ASSUME_ATFCTS
  59       if (errno_out == ENOSYS)
  60         __have_atfcts = -1;
  61       else
  62 #endif
  63         {
  64           __set_errno (errno_out);
  65           return -1;
  66         }
  67     }
  68 #endif /* __NR_fstatat64 */
  69
  70   if (flag & ~AT_SYMLINK_NOFOLLOW)
  71     {
  72       __set_errno (EINVAL);
  73       return -1;
  74     }
  75
  76   char *buf = NULL;
  77
  78   if (fd != AT_FDCWD && file[0] != '/')
  79     {
  80       size_t filelen = strlen (file);
  81       if (__builtin_expect (filelen == 0, 0))
  82         {
  83           __set_errno (ENOENT);
  84           return -1;
  85         }
  86
  87       static const char procfd[] = "/proc/self/fd/%d/%s";
  88       /* Buffer for the path name we are going to use.  It consists of
  89          - the string /proc/self/fd/
  90          - the file descriptor number
  91          - the file name provided.
  92          The final NUL is included in the sizeof.   A bit of overhead
  93          due to the format elements compensates for possible negative
  94          numbers.  */
  95       size_t buflen = sizeof (procfd) + sizeof (int) * 3 + filelen;
  96       buf = alloca (buflen);
  97
  98       __snprintf (buf, buflen, procfd, fd, file);
  99       file = buf;
 100     }
 101
 102 #ifdef __NR_stat64
 103   if (!__libc_missing_axp_stat64)
 104     {
 105       if (flag & AT_SYMLINK_NOFOLLOW)
 106         result = INTERNAL_SYSCALL (lstat64, err, 2, file, st);
 107       else
 108         result = INTERNAL_SYSCALL (stat64, err, 2, file, st);
 109
 110       if (__builtin_expect (!INTERNAL_SYSCALL_ERROR_P (result, err), 1))
 111         return result;
 112       errno_out = INTERNAL_SYSCALL_ERRNO (result, err);
 113 # if __ASSUME_STAT64_SYSCALL == 0
 114       if (errno_out == ENOSYS)
 115         __libc_missing_axp_stat64 = 1;
 116       else
 117 # endif
 118         goto fail;
 119     }
 120 #endif /* __NR_stat64 */
 121
 122   struct kernel_stat kst;
 123
 124   if (flag & AT_SYMLINK_NOFOLLOW)
 125     result = INTERNAL_SYSCALL (lstat, err, 2, file, &kst);
 126   else
 127     result = INTERNAL_SYSCALL (stat, err, 2, file, &kst);
 128
 129   if (__builtin_expect (!INTERNAL_SYSCALL_ERROR_P (result, err), 1))
 130     return __xstat_conv (vers, &kst, st);
 131   errno_out = INTERNAL_SYSCALL_ERRNO (result, err);
 132
 133  fail:
 134   __atfct_seterrno (errno_out, fd, buf);
 135
 136   return -1;
 137 }
 138 libc_hidden_def (__fxstatat)
 139 strong_alias (__fxstatat, __fxstatat64);
 140 libc_hidden_ver(__fxstatat, __fxstatat64);