glibc/sysdeps/unix/sysv/linux/i386/setfsuid.c

/* Copyright (C) 1998, 2000 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <errno.h>
#include <sys/types.h>
#include <sys/fsuid.h>

#include <sysdep.h>
#include <sys/syscall.h>

#include <linux/posix_types.h>
#include "kernel-features.h"

#ifdef __NR_setfsuid

extern int __syscall_setfsuid (__kernel_uid_t);

# ifdef __NR_setfsuid32
extern int __syscall_setfsuid32 (__kernel_uid32_t);
#  if __ASSUME_32BITUIDS == 0
/* This variable is shared with all files that need to check for 32bit
   uids.  */
extern int __libc_missing_32bit_uids;
#  endif
# endif /* __NR_setfsuid32 */

int
setfsuid (uid_t uid)
{
# if  __ASSUME_32BITUIDS > 0
  return INLINE_SYSCALL (setfsuid32, 1, uid);
# else  
#  ifdef __NR_setfsuid32
  if (__libc_missing_32bit_uids <= 0)
    {
      int result;
      int saved_errno = errno;

      result = INLINE_SYSCALL (setfsuid32, 1, uid);
      if (result == 0 || errno != ENOSYS)
	return result;

      __set_errno (saved_errno);
      __libc_missing_32bit_uids = 1;
    }
#  endif /* __NR_setfsuid32 */

  if (uid != (uid_t) ((__kernel_uid_t) uid))
    {
      __set_errno (EINVAL);
      return -1;
    }

  return INLINE_SYSCALL (setfsuid, 1, uid);
# endif
}
#endif