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

   1 /* Copyright (C) 1998,2000,2003,2004,2006 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 #include <setxid.h>
  22 #include <linux/posix_types.h>
  23 #include <kernel-features.h>
  24
  25
  26 #ifdef __NR_setreuid32
  27 # if __ASSUME_32BITUIDS == 0
  28 /* This variable is shared with all files that need to check for 32bit
  29    uids.  */
  30 extern int __libc_missing_32bit_uids;
  31 # endif
  32 #endif /* __NR_setreuid32 */
  33
  34 int
  35 __setreuid (uid_t ruid, uid_t euid)
  36 {
  37   int result;
  38
  39 #if __ASSUME_32BITUIDS > 0
  40   result = INLINE_SETXID_SYSCALL (setreuid32, 2, ruid, euid);
  41 #else
  42 # ifdef __NR_setreuid32
  43   if (__libc_missing_32bit_uids <= 0)
  44     {
  45       int saved_errno = errno;
  46
  47       result = INLINE_SETXID_SYSCALL (setreuid32, 2, ruid, euid);
  48
  49       if (result == 0)
  50         goto out;
  51       if (errno != ENOSYS)
  52         return result;
  53
  54       __set_errno (saved_errno);
  55       __libc_missing_32bit_uids = 1;
  56     }
  57 # endif /* __NR_setreuid32 */
  58   if (((ruid + 1) > (uid_t) ((__kernel_uid_t) -1U))
  59       || ((euid + 1) > (uid_t) ((__kernel_uid_t) -1U)))
  60     {
  61       __set_errno (EINVAL);
  62       return -1;
  63     }
  64
  65   result = INLINE_SETXID_SYSCALL (setreuid, 2, ruid, euid);
  66 # ifdef __NR_setreuid32
  67  out:
  68 # endif
  69 #endif
  70
  71   return result;
  72 }
  73 #ifndef __setreuid
  74 weak_alias (__setreuid, setreuid)
  75 #endif