sysdeps/unix/sysv/linux/i386/getuid.c

   1 /* Copyright (C) 2000, 2003, 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 #include <errno.h>
  20 #include <unistd.h>
  21
  22 #include <sysdep.h>
  23 #include <sys/syscall.h>
  24
  25 #include <kernel-features.h>
  26
  27 #ifdef __NR_getuid32
  28 # if __ASSUME_32BITUIDS == 0
  29 /* This variable is shared with all files that need to check for 32bit
  30    uids.  This is the definition.
  31    -1 if libc does not know yet whether kernel has 32bit uids or not.
  32    0 if it does have them.
  33    1 if it does not have them.  */
  34 int __libc_missing_32bit_uids attribute_hidden = -1;
  35 # endif
  36 #endif /* __NR_getuid32 */
  37
  38 uid_t
  39 __getuid (void)
  40 {
  41   INTERNAL_SYSCALL_DECL (err);
  42 #if __ASSUME_32BITUIDS > 0
  43   /* No error checking.  */
  44   return INTERNAL_SYSCALL (getuid32, err, 0);
  45 #else
  46 # ifdef __NR_getuid32
  47   if (__libc_missing_32bit_uids <= 0)
  48     {
  49       int result;
  50
  51       result = INTERNAL_SYSCALL (getuid32, err, 0);
  52       if (! INTERNAL_SYSCALL_ERROR_P (result, err)
  53           || INTERNAL_SYSCALL_ERRNO (result, err) != ENOSYS)
  54         return result;
  55
  56       __libc_missing_32bit_uids = 1;
  57     }
  58 # endif /* __NR_getuid32 */
  59
  60   /* No error checking.  */
  61   return INTERNAL_SYSCALL (getuid, err, 0);
  62 #endif
  63 }
  64
  65 weak_alias (__getuid, getuid)