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

   1 /* Copyright (C) 1995-1998,2000,2002,2003,2004,2006
   2         Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <errno.h>
  21 #include <unistd.h>
  22 #include <setxid.h>
  23 #include <kernel-features.h>
  24
  25
  26 #ifdef __NR_setresgid
  27 extern int __setresgid (uid_t rgid, uid_t egid, uid_t sgid);
  28 #endif
  29
  30 int
  31 setegid (gid)
  32      gid_t gid;
  33 {
  34   int result;
  35
  36   if (gid == (gid_t) ~0)
  37     {
  38       __set_errno (EINVAL);
  39       return -1;
  40     }
  41
  42 #if __ASSUME_32BITUIDS > 0
  43   result = INLINE_SETXID_SYSCALL (setresgid32, 3, -1, gid, -1);
  44 #else
  45   /* First try the syscall.  */
  46 # ifdef __NR_setresgid
  47   result = __setresgid (-1, gid, -1);
  48 #  if __ASSUME_SETRESGID_SYSCALL > 0
  49   if (0)
  50 #  else
  51   if (result == -1 && errno == ENOSYS)
  52 #  endif
  53     /* No system call available.  Use emulation.  This may not work
  54        since `setregid' also sets the saved user ID when GID is not
  55        equal to the real user ID, making it impossible to switch back.  */
  56 # endif
  57     result = __setregid (-1, gid);
  58 #endif
  59
  60   return result;
  61 }
  62 libc_hidden_def (setegid)