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, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #define __fxstatat64 __fxstatat64_disable
  20
  21 #include <errno.h>
  22 #include <fcntl.h>
  23 #include <stddef.h>
  24 #include <stdio.h>
  25 #include <sys/stat.h>
  26 #include <kernel_stat.h>
  27 #include <sysdep.h>
  28 #include <sys/syscall.h>
  29 #include <xstatconv.h>
  30
  31 #undef __fxstatat64
  32
  33 #ifdef __ASSUME_ATFCTS
  34 # define __have_atfcts 1
  35 #endif
  36 #ifdef __ASSUME_STAT64_SYSCALL
  37 # define __libc_missing_axp_stat64 0
  38 #endif
  39
  40 /* Get information about the file NAME in BUF.  */
  41 int
  42 __fxstatat (int vers, int fd, const char *file, struct stat *st, int flag)
  43 {
  44   INTERNAL_SYSCALL_DECL (err);
  45   int result, errno_out;
  46
  47   /* ??? The __fxstatat entry point is new enough that it must be using
  48      vers == _STAT_VER_KERNEL64.  For the benefit of dl-fxstatat64.c, we
  49      cannot actually check this, lest the compiler not optimize the rest
  50      of the function away.  */
  51
  52 #ifdef __NR_fstatat64
  53   if (__have_atfcts >= 0)
  54     {
  55       result = INTERNAL_SYSCALL (fstatat64, err, 4, fd, file, st, flag);
  56       if (__builtin_expect (!INTERNAL_SYSCALL_ERROR_P (result, err), 1))
  57         return result;
  58       errno_out = INTERNAL_SYSCALL_ERRNO (result, err);
  59 #ifndef __ASSUME_ATFCTS
  60       if (errno_out == ENOSYS)
  61         __have_atfcts = -1;
  62       else
  63 #endif
  64         {
  65           __set_errno (errno_out);
  66           return -1;
  67         }
  68     }
  69 #endif /* __NR_fstatat64 */
  70
  71   if (flag & ~AT_SYMLINK_NOFOLLOW)
  72     {
  73       __set_errno (EINVAL);
  74       return -1;
  75     }
  76
  77   char *buf = NULL;
  78
  79   if (fd != AT_FDCWD && file[0] != '/')
  80     {
  81       size_t filelen = strlen (file);
  82       if (__builtin_expect (filelen == 0, 0))
  83         {
  84           __set_errno (ENOENT);
  85           return -1;
  86         }
  87
  88       static const char procfd[] = "/proc/self/fd/%d/%s";
  89       /* Buffer for the path name we are going to use.  It consists of
  90          - the string /proc/self/fd/
  91          - the file descriptor number
  92          - the file name provided.
  93          The final NUL is included in the sizeof.   A bit of overhead
  94          due to the format elements compensates for possible negative
  95          numbers.  */
  96       size_t buflen = sizeof (procfd) + sizeof (int) * 3 + filelen;
  97       buf = alloca (buflen);
  98
  99       __snprintf (buf, buflen, procfd, fd, file);
 100       file = buf;
 101     }
 102
 103 #ifdef __NR_stat64
 104   if (!__libc_missing_axp_stat64)
 105     {
 106       if (flag & AT_SYMLINK_NOFOLLOW)
 107         result = INTERNAL_SYSCALL (lstat64, err, 2, file, st);
 108       else
 109         result = INTERNAL_SYSCALL (stat64, err, 2, file, st);
 110
 111       if (__builtin_expect (!INTERNAL_SYSCALL_ERROR_P (result, err), 1))
 112         return result;
 113       errno_out = INTERNAL_SYSCALL_ERRNO (result, err);
 114 # if __ASSUME_STAT64_SYSCALL == 0
 115       if (errno_out == ENOSYS)
 116         __libc_missing_axp_stat64 = 1;
 117       else
 118 # endif
 119         goto fail;
 120     }
 121 #endif /* __NR_stat64 */
 122
 123   struct kernel_stat kst;
 124
 125   if (flag & AT_SYMLINK_NOFOLLOW)
 126     result = INTERNAL_SYSCALL (lstat, err, 2, file, &kst);
 127   else
 128     result = INTERNAL_SYSCALL (stat, err, 2, file, &kst);
 129
 130   if (__builtin_expect (!INTERNAL_SYSCALL_ERROR_P (result, err), 1))
 131     return __xstat_conv (vers, &kst, st);
 132   errno_out = INTERNAL_SYSCALL_ERRNO (result, err);
 133
 134  fail:
 135   __atfct_seterrno (errno_out, fd, buf);
 136
 137   return -1;
 138 }
 139 libc_hidden_def (__fxstatat)
 140 strong_alias (__fxstatat, __fxstatat64);
 141 libc_hidden_ver(__fxstatat, __fxstatat64);