sysdeps/unix/sysv/linux/i386/setuid.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, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <unistd.h>
  20 #include <setxid.h>
  21 #include <linux/posix_types.h>
  22 #include <kernel-features.h>
  23
  24
  25 #ifdef __NR_setuid32
  26 # if __ASSUME_32BITUIDS == 0
  27 /* This variable is shared with all files that need to check for 32bit
  28    uids.  */
  29 extern int __libc_missing_32bit_uids;
  30 # endif
  31 #endif /* __NR_setuid32 */
  32
  33 int
  34 __setuid (uid_t uid)
  35 {
  36   int result;
  37
  38 #if __ASSUME_32BITUIDS > 0 && defined __NR_setuid32
  39   result = INLINE_SETXID_SYSCALL (setuid32, 1, uid);
  40 #else
  41 # ifdef __NR_setuid32
  42   if (__libc_missing_32bit_uids <= 0)
  43     {
  44       int saved_errno = errno;
  45
  46       result = INLINE_SETXID_SYSCALL (setuid32, 1, uid);
  47       if (result == 0)
  48         goto out;
  49       if (errno != ENOSYS)
  50         return result;
  51
  52       __set_errno (saved_errno);
  53       __libc_missing_32bit_uids = 1;
  54     }
  55 # endif /* __NR_setuid32 */
  56
  57   if (uid == (uid_t) ~0
  58       || uid != (uid_t) ((__kernel_uid_t) uid))
  59     {
  60       __set_errno (EINVAL);
  61       return -1;
  62     }
  63
  64   result = INLINE_SETXID_SYSCALL (setuid, 1, uid);
  65 # ifdef __NR_setuid32
  66  out:
  67 # endif
  68 #endif
  69
  70   return result;
  71 }
  72 #ifndef __setuid
  73 weak_alias (__setuid, setuid)
  74 #endif