sysdeps/unix/sysv/linux/signalfd.c

   1 /* Copyright (C) 2007-2015 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 <signal.h>
  20 #include <sys/signalfd.h>
  21 #include <sysdep.h>
  22 #include <kernel-features.h>
  23
  24
  25 int
  26 signalfd (int fd, const sigset_t *mask, int flags)
  27 {
  28 #ifdef __NR_signalfd4
  29 # ifndef __ASSUME_SIGNALFD4
  30   INTERNAL_SYSCALL_DECL (err);
  31   int res = INTERNAL_SYSCALL (signalfd4, err, 4, fd, mask, _NSIG / 8,
  32                               flags);
  33   if (!__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (res, err))
  34       || INTERNAL_SYSCALL_ERRNO (res, err) != ENOSYS)
  35     return res;
  36 # else
  37   return INLINE_SYSCALL_RETURN (signalfd4, 4, int, fd, mask, _NSIG / 8,
  38                                 flags);
  39 # endif
  40 #endif
  41
  42 #ifndef __ASSUME_SIGNALFD4
  43   /* The old system call has no flag parameter which is bad.  So we have
  44      to wait until we have to support to pass additional values to the
  45      kernel (sys_indirect) before implementing setting flags like
  46      O_NONBLOCK etc.  */
  47   if (flags != 0)
  48     return INLINE_SYSCALL_ERROR_RETURN (-EINVAL, int, -1);
  49
  50 # ifdef __NR_signalfd
  51   return INLINE_SYSCALL_RETURN (signalfd, 3, int, fd, mask, _NSIG / 8);
  52 # else
  53   return INLINE_SYSCALL_ERROR_RETURN (-ENOSYS, int, -1);
  54 # endif
  55 #elif !defined __NR_signalfd4
  56 # error "__ASSUME_SIGNALFD4 defined but not __NR_signalfd4"
  57 #endif
  58 }