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 <string.h>
  24 #include <sys/stat.h>
  25 #include <kernel_stat.h>
  26
  27 #include <sysdep.h>
  28 #include <sys/syscall.h>
  29 #include <bp-checks.h>
  30
  31 #include "kernel-features.h"
  32
  33 #if __ASSUME_STAT64_SYSCALL == 0
  34 # include <xstatconv.h>
  35 #endif
  36
  37 #ifdef __NR_stat64
  38 # if  __ASSUME_STAT64_SYSCALL == 0
  39 /* The variable is shared between all wrappers around *stat64 calls.
  40    This is the definition.  */
  41 extern int __have_no_stat64;
  42 # endif
  43 #endif
  44
  45 /* Get information about the file NAME in BUF.  */
  46
  47 int
  48 __fxstatat64 (int vers, int fd, const char *file, struct stat64 *st, int flag)
  49 {
  50   if (flag & ~AT_SYMLINK_NOFOLLOW)
  51     {
  52       __set_errno (EINVAL);
  53       return -1;
  54     }
  55
  56   char *buf = NULL;
  57
  58   if (fd != AT_FDCWD && file[0] != '/')
  59     {
  60       size_t filelen = strlen (file);
  61       static const char procfd[] = "/proc/self/fd/%d/%s";
  62       /* Buffer for the path name we are going to use.  It consists of
  63          - the string /proc/self/fd/
  64          - the file descriptor number
  65          - the file name provided.
  66          The final NUL is included in the sizeof.   A bit of overhead
  67          due to the format elements compensates for possible negative
  68          numbers.  */
  69       size_t buflen = sizeof (procfd) + sizeof (int) * 3 + filelen;
  70       buf = alloca (buflen);
  71
  72       __snprintf (buf, buflen, procfd, fd, file);
  73       file = buf;
  74     }
  75
  76   int result;
  77   INTERNAL_SYSCALL_DECL (err);
  78
  79 #if __ASSUME_STAT64_SYSCALL > 0
  80   if (flag & AT_SYMLINK_NOFOLLOW)
  81     result = INTERNAL_SYSCALL (lstat64, err, 2, CHECK_STRING (file),
  82                                CHECK_1 (st));
  83   else
  84     result = INTERNAL_SYSCALL (stat64, err, 2, CHECK_STRING (file),
  85                                CHECK_1 (st));
  86   if (__builtin_expect (!INTERNAL_SYSCALL_ERROR_P (result, err), 1))
  87     {
  88 # if defined _HAVE_STAT64___ST_INO && __ASSUME_ST_INO_64_BIT == 0
  89       if (st->__st_ino != (__ino_t) st->st_ino)
  90         st->st_ino = st->__st_ino;
  91 # endif
  92       return result;
  93     }
  94 #else
  95   struct kernel_stat kst;
  96 # if defined __NR_stat64
  97   if (! __have_no_stat64)
  98     {
  99       if (flag & AT_SYMLINK_NOFOLLOW)
 100         result = INTERNAL_SYSCALL (lstat64, err, 2, CHECK_STRING (file),
 101                                    CHECK_1 (st));
 102       else
 103         result = INTERNAL_SYSCALL (stat64, err, 2, CHECK_STRING (file),
 104                                    CHECK_1 (st));
 105
 106       if (__builtin_expect (!INTERNAL_SYSCALL_ERROR_P (result, err), 1))
 107         {
 108 #  if defined _HAVE_STAT64___ST_INO && __ASSUME_ST_INO_64_BIT == 0
 109           if (st->__st_ino != (__ino_t) st->st_ino)
 110             st->st_ino = st->__st_ino;
 111 #  endif
 112           return result;
 113         }
 114       if (INTERNAL_SYSCALL_ERRNO (result, err) != ENOSYS)
 115         goto fail;
 116
 117       __have_no_stat64 = 1;
 118     }
 119 # endif
 120
 121   if (flag & AT_SYMLINK_NOFOLLOW)
 122     result = INTERNAL_SYSCALL (lstat, err, 2, CHECK_STRING (file),
 123                                __ptrvalue (&kst));
 124   else
 125     result = INTERNAL_SYSCALL (stat, err, 2, CHECK_STRING (file),
 126                                __ptrvalue (&kst));
 127
 128   if (__builtin_expect (!INTERNAL_SYSCALL_ERROR_P (result, err), 1))
 129     return __xstat64_conv (vers, &kst, st);
 130
 131  fail:
 132 #endif
 133   __atfct_seterrno (INTERNAL_SYSCALL_ERRNO (result, err), fd, buf);
 134
 135   return -1;
 136 }