sysdeps/unix/sysv/linux/fxstatat64.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 #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 (__builtin_expect (vers != _STAT_VER_LINUX, 0))
  51     {
  52       __set_errno (EINVAL);
  53       return -1;
  54     }
  55
  56   int result;
  57   INTERNAL_SYSCALL_DECL (err);
  58
  59 #ifdef __NR_fstatat64
  60 # ifndef __ASSUME_ATFCTS
  61   if (__have_atfcts >= 0)
  62 # endif
  63     {
  64       result = INTERNAL_SYSCALL (fstatat64, err, 4, fd, file, st, flag);
  65 # ifndef __ASSUME_ATFCTS
  66       if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (result, err), 1)
  67           && INTERNAL_SYSCALL_ERRNO (result, err) == ENOSYS)
  68         __have_atfcts = -1;
  69       else
  70 # endif
  71         if (!__builtin_expect (INTERNAL_SYSCALL_ERROR_P (result, err), 1))
  72           return 0;
  73         else
  74           {
  75             __set_errno (INTERNAL_SYSCALL_ERRNO (result, err));
  76             return -1;
  77           }
  78     }
  79 #endif
  80
  81 #ifndef __ASSUME_ATFCTS
  82   if (flag & ~AT_SYMLINK_NOFOLLOW)
  83     {
  84       __set_errno (EINVAL);
  85       return -1;
  86     }
  87
  88   char *buf = NULL;
  89
  90   if (fd != AT_FDCWD && file[0] != '/')
  91     {
  92       size_t filelen = strlen (file);
  93       if (__builtin_expect (filelen == 0, 0))
  94         {
  95           __set_errno (ENOENT);
  96           return -1;
  97         }
  98
  99       static const char procfd[] = "/proc/self/fd/%d/%s";
 100       /* Buffer for the path name we are going to use.  It consists of
 101          - the string /proc/self/fd/
 102          - the file descriptor number
 103          - the file name provided.
 104          The final NUL is included in the sizeof.   A bit of overhead
 105          due to the format elements compensates for possible negative
 106          numbers.  */
 107       size_t buflen = sizeof (procfd) + sizeof (int) * 3 + filelen;
 108       buf = alloca (buflen);
 109
 110       __snprintf (buf, buflen, procfd, fd, file);
 111       file = buf;
 112     }
 113
 114 # if __ASSUME_STAT64_SYSCALL > 0
 115   if (flag & AT_SYMLINK_NOFOLLOW)
 116     result = INTERNAL_SYSCALL (lstat64, err, 2, CHECK_STRING (file),
 117                                CHECK_1 (st));
 118   else
 119     result = INTERNAL_SYSCALL (stat64, err, 2, CHECK_STRING (file),
 120                                CHECK_1 (st));
 121   if (__builtin_expect (!INTERNAL_SYSCALL_ERROR_P (result, err), 1))
 122     {
 123 #  if defined _HAVE_STAT64___ST_INO && __ASSUME_ST_INO_64_BIT == 0
 124       if (st->__st_ino != (__ino_t) st->st_ino)
 125         st->st_ino = st->__st_ino;
 126 #  endif
 127       return result;
 128     }
 129 # else
 130   struct kernel_stat kst;
 131 #  ifdef __NR_stat64
 132   if (! __have_no_stat64)
 133     {
 134       if (flag & AT_SYMLINK_NOFOLLOW)
 135         result = INTERNAL_SYSCALL (lstat64, err, 2, CHECK_STRING (file),
 136                                    CHECK_1 (st));
 137       else
 138         result = INTERNAL_SYSCALL (stat64, err, 2, CHECK_STRING (file),
 139                                    CHECK_1 (st));
 140
 141       if (__builtin_expect (!INTERNAL_SYSCALL_ERROR_P (result, err), 1))
 142         {
 143 #   if defined _HAVE_STAT64___ST_INO && __ASSUME_ST_INO_64_BIT == 0
 144           if (st->__st_ino != (__ino_t) st->st_ino)
 145             st->st_ino = st->__st_ino;
 146 #   endif
 147           return result;
 148         }
 149       if (INTERNAL_SYSCALL_ERRNO (result, err) != ENOSYS)
 150         goto fail;
 151
 152       __have_no_stat64 = 1;
 153     }
 154 #  endif
 155
 156   if (flag & AT_SYMLINK_NOFOLLOW)
 157     result = INTERNAL_SYSCALL (lstat, err, 2, CHECK_STRING (file),
 158                                __ptrvalue (&kst));
 159   else
 160     result = INTERNAL_SYSCALL (stat, err, 2, CHECK_STRING (file),
 161                                __ptrvalue (&kst));
 162
 163   if (__builtin_expect (!INTERNAL_SYSCALL_ERROR_P (result, err), 1))
 164     return __xstat64_conv (vers, &kst, st);
 165
 166  fail:
 167 # endif
 168   __atfct_seterrno (INTERNAL_SYSCALL_ERRNO (result, err), fd, buf);
 169
 170   return -1;
 171 #endif
 172 }
 173 libc_hidden_def (__fxstatat64)