sysdeps/unix/sysv/linux/fxstatat64.c

   1 /* Copyright (C) 2005 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 #include <errno.h>
  20 #include <fcntl.h>
  21 #include <stddef.h>
  22 #include <stdio.h>
  23 #include <sys/stat.h>
  24 #include <kernel_stat.h>
  25
  26 #include <sysdep.h>
  27 #include <sys/syscall.h>
  28 #include <bp-checks.h>
  29
  30 #include "kernel-features.h"
  31
  32 #if __ASSUME_STAT64_SYSCALL == 0
  33 # include <xstatconv.h>
  34 #endif
  35
  36 #ifdef __NR_stat64
  37 # if  __ASSUME_STAT64_SYSCALL == 0
  38 /* The variable is shared between all wrappers around *stat64 calls.
  39    This is the definition.  */
  40 extern int __have_no_stat64;
  41 # endif
  42 #endif
  43
  44 /* Get information about the file NAME in BUF.  */
  45
  46 int
  47 __fxstatat64 (int vers, int fd, const char *file, struct stat64 *st, int flag)
  48 {
  49   if (flag & ~AT_SYMLINK_NOFOLLOW)
  50     {
  51       __set_errno (EINVAL);
  52       return -1;
  53     }
  54
  55   char *buf = NULL;
  56
  57   if (fd != AT_FDCWD && file[0] != '/')
  58     {
  59       size_t filelen = strlen (file);
  60       static const char procfd[] = "/proc/self/fd/%d/%s";
  61       /* Buffer for the path name we are going to use.  It consists of
  62          - the string /proc/self/fd/
  63          - the file descriptor number
  64          - the file name provided.
  65          The final NUL is included in the sizeof.   A bit of overhead
  66          due to the format elements compensates for possible negative
  67          numbers.  */
  68       size_t buflen = sizeof (procfd) + sizeof (int) * 3 + filelen;
  69       buf = alloca (buflen);
  70
  71       __snprintf (buf, buflen, procfd, fd, file);
  72       file = buf;
  73     }
  74
  75   int result;
  76   INTERNAL_SYSCALL_DECL (err);
  77
  78 #if __ASSUME_STAT64_SYSCALL > 0
  79   if (flag & AT_SYMLINK_NOFOLLOW)
  80     result = INTERNAL_SYSCALL (lstat64, err, 2, CHECK_STRING (file),
  81                                CHECK_1 (st));
  82   else
  83     result = INTERNAL_SYSCALL (stat64, err, 2, CHECK_STRING (file),
  84                                CHECK_1 (st));
  85   if (__builtin_expect (!INTERNAL_SYSCALL_ERROR_P (result, err), 1))
  86     {
  87 # if defined _HAVE_STAT64___ST_INO && __ASSUME_ST_INO_64_BIT == 0
  88       if (st->__st_ino != (__ino_t) st->st_ino)
  89         st->st_ino = st->__st_ino;
  90 # endif
  91       return result;
  92     }
  93 #else
  94   struct kernel_stat kst;
  95 # if defined __NR_stat64
  96   if (! __have_no_stat64)
  97     {
  98       if (flag & AT_SYMLINK_NOFOLLOW)
  99         result = INTERNAL_SYSCALL (lstat64, err, 2, CHECK_STRING (file),
 100                                    CHECK_1 (st));
 101       else
 102         result = INTERNAL_SYSCALL (stat64, err, 2, CHECK_STRING (file),
 103                                    CHECK_1 (st));
 104
 105       if (__builtin_expect (!INTERNAL_SYSCALL_ERROR_P (result, err), 1))
 106         {
 107 #  if defined _HAVE_STAT64___ST_INO && __ASSUME_ST_INO_64_BIT == 0
 108           if (st->__st_ino != (__ino_t) st->st_ino)
 109             st->st_ino = st->__st_ino;
 110 #  endif
 111           return result;
 112         }
 113       if (INTERNAL_SYSCALL_ERRNO (result, err) != ENOSYS)
 114         goto fail;
 115
 116       __have_no_stat64 = 1;
 117     }
 118 # endif
 119
 120   if (flag & AT_SYMLINK_NOFOLLOW)
 121     result = INTERNAL_SYSCALL (lstat, err, 2, CHECK_STRING (file),
 122                                __ptrvalue (&kst));
 123   else
 124     result = INTERNAL_SYSCALL (stat, err, 2, CHECK_STRING (file),
 125                                __ptrvalue (&kst));
 126
 127   if (__builtin_expect (!INTERNAL_SYSCALL_ERROR_P (result, err), 1))
 128     return __xstat64_conv (vers, &kst, st);
 129
 130  fail:
 131 #endif
 132   __atfct_seterrno (INTERNAL_SYSCALL_ERRNO (result, err), fd, buf);
 133
 134   return -1;
 135 }