sysdeps/unix/sysv/linux/wordsize-64/fxstatat.c

   1 /* Copyright (C) 2005, 2006 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 /* Ho hum, since fxstatat == fxstatat64 we must get rid of the
  20    prototype or gcc will complain since they don't strictly match.  */
  21 #define __fxstatat64 __fxstatat64_disable
  22
  23 #include <errno.h>
  24 #include <fcntl.h>
  25 #include <stddef.h>
  26 #include <stdio.h>
  27 #include <string.h>
  28 #include <sys/stat.h>
  29
  30 #include <sysdep.h>
  31 #include <kernel-features.h>
  32 #include <sys/syscall.h>
  33 #include <bp-checks.h>
  34
  35
  36 /* Get information about the file NAME relative to FD in ST.  */
  37 int
  38 __fxstatat (int vers, int fd, const char *file, struct stat *st, int flag)
  39 {
  40   if (vers != _STAT_VER_KERNEL && vers != _STAT_VER_LINUX)
  41     {
  42       __set_errno (EINVAL);
  43       return -1;
  44     }
  45
  46   int res;
  47
  48 #ifdef __NR_newfstatat
  49 # ifndef __ASSUME_ATFCTS
  50   if (__have_atfcts >= 0)
  51 # endif
  52     {
  53       res = INLINE_SYSCALL (newfstatat, 4, fd, file, st, flag);
  54 # ifndef __ASSUME_ATFCTS
  55       if (res == -1 && errno == ENOSYS)
  56         __have_atfcts = -1;
  57       else
  58 # endif
  59         return res;
  60     }
  61 #endif
  62
  63 #ifndef __ASSUME_ATFCTS
  64   if ((flag & ~AT_SYMLINK_NOFOLLOW) != 0)
  65     {
  66       __set_errno (EINVAL);
  67       return -1;
  68     }
  69
  70   char *buf = NULL;
  71
  72   if (fd != AT_FDCWD && file[0] != '/')
  73     {
  74       size_t filelen = strlen (file);
  75       static const char procfd[] = "/proc/self/fd/%d/%s";
  76       /* Buffer for the path name we are going to use.  It consists of
  77          - the string /proc/self/fd/
  78          - the file descriptor number
  79          - the file name provided.
  80          The final NUL is included in the sizeof.   A bit of overhead
  81          due to the format elements compensates for possible negative
  82          numbers.  */
  83       size_t buflen = sizeof (procfd) + sizeof (int) * 3 + filelen;
  84       buf = alloca (buflen);
  85
  86       __snprintf (buf, buflen, procfd, fd, file);
  87       file = buf;
  88     }
  89
  90   INTERNAL_SYSCALL_DECL (err);
  91
  92   if (flag & AT_SYMLINK_NOFOLLOW)
  93     res = INTERNAL_SYSCALL (lstat, err, 2, file, CHECK_1 (st));
  94   else
  95     res = INTERNAL_SYSCALL (stat, err, 2, file, CHECK_1 (st));
  96
  97   if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (res, err), 0))
  98     {
  99       __atfct_seterrno (INTERNAL_SYSCALL_ERRNO (res, err), fd, buf);
 100       res = -1;
 101     }
 102
 103   return res;
 104 #endif
 105 }
 106 libc_hidden_def (__fxstatat)
 107 #undef __fxstatat64
 108 strong_alias (__fxstatat, __fxstatat64);
 109 strong_alias (__fxstatat64, __GI___fxstatat64)