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

   1 /* Copyright (C) 2005-2014 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
  36 /* Get information about the file NAME in BUF.  */
  37 int
  38 __fxstatat (int vers, int fd, const char *file, struct stat *st, int flag)
  39 {
  40   INTERNAL_SYSCALL_DECL (err);
  41   int result, errno_out;
  42
  43   /* ??? The __fxstatat entry point is new enough that it must be using
  44      vers == _STAT_VER_KERNEL64.  For the benefit of dl-fxstatat64.c, we
  45      cannot actually check this, lest the compiler not optimize the rest
  46      of the function away.  */
  47
  48 #ifdef __NR_fstatat64
  49   if (__have_atfcts >= 0)
  50     {
  51       result = INTERNAL_SYSCALL (fstatat64, err, 4, fd, file, st, flag);
  52       if (__builtin_expect (!INTERNAL_SYSCALL_ERROR_P (result, err), 1))
  53         return result;
  54       errno_out = INTERNAL_SYSCALL_ERRNO (result, err);
  55 #ifndef __ASSUME_ATFCTS
  56       if (errno_out == ENOSYS)
  57         __have_atfcts = -1;
  58       else
  59 #endif
  60         {
  61           __set_errno (errno_out);
  62           return -1;
  63         }
  64     }
  65 #endif /* __NR_fstatat64 */
  66
  67   if (flag & ~AT_SYMLINK_NOFOLLOW)
  68     {
  69       __set_errno (EINVAL);
  70       return -1;
  71     }
  72
  73   char *buf = NULL;
  74
  75   if (fd != AT_FDCWD && file[0] != '/')
  76     {
  77       size_t filelen = strlen (file);
  78       if (__builtin_expect (filelen == 0, 0))
  79         {
  80           __set_errno (ENOENT);
  81           return -1;
  82         }
  83
  84       static const char procfd[] = "/proc/self/fd/%d/%s";
  85       /* Buffer for the path name we are going to use.  It consists of
  86          - the string /proc/self/fd/
  87          - the file descriptor number
  88          - the file name provided.
  89          The final NUL is included in the sizeof.   A bit of overhead
  90          due to the format elements compensates for possible negative
  91          numbers.  */
  92       size_t buflen = sizeof (procfd) + sizeof (int) * 3 + filelen;
  93       buf = alloca (buflen);
  94
  95       __snprintf (buf, buflen, procfd, fd, file);
  96       file = buf;
  97     }
  98
  99   if (flag & AT_SYMLINK_NOFOLLOW)
 100     result = INTERNAL_SYSCALL (lstat64, err, 2, file, st);
 101   else
 102     result = INTERNAL_SYSCALL (stat64, err, 2, file, st);
 103   if (__builtin_expect (!INTERNAL_SYSCALL_ERROR_P (result, err), 1))
 104     return result;
 105
 106   errno_out = INTERNAL_SYSCALL_ERRNO (result, err);
 107   __atfct_seterrno (errno_out, fd, buf);
 108
 109   return -1;
 110 }
 111 libc_hidden_def (__fxstatat)
 112 strong_alias (__fxstatat, __fxstatat64);
 113 libc_hidden_ver(__fxstatat, __fxstatat64);