sysdeps/unix/sysv/linux/accept4.c

   1 /* Copyright (C) 2008-2014 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@redhat.com>, 2008.
   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, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <signal.h>
  21 #include <sys/socket.h>
  22
  23 #include <sysdep-cancel.h>
  24 #include <sys/syscall.h>
  25 #include <kernel-features.h>
  26
  27
  28 #ifdef __NR_accept4
  29 int
  30 accept4 (int fd, __SOCKADDR_ARG addr, socklen_t *addr_len, int flags)
  31 {
  32   if (SINGLE_THREAD_P)
  33     return INLINE_SYSCALL (accept4, 4, fd, addr.__sockaddr__, addr_len, flags);
  34
  35   int oldtype = LIBC_CANCEL_ASYNC ();
  36
  37   int result = INLINE_SYSCALL (accept4, 4, fd, addr.__sockaddr__, addr_len,
  38                                flags);
  39
  40   LIBC_CANCEL_RESET (oldtype);
  41
  42   return result;
  43 }
  44 #elif defined __NR_socketcall
  45 # ifndef __ASSUME_ACCEPT4
  46 extern int __internal_accept4 (int fd, __SOCKADDR_ARG addr,
  47                                socklen_t *addr_len, int flags)
  48      attribute_hidden;
  49
  50 static int have_accept4;
  51
  52 int
  53 accept4 (int fd, __SOCKADDR_ARG addr, socklen_t *addr_len, int flags)
  54 {
  55   if (__builtin_expect (have_accept4 >= 0, 1))
  56     {
  57       int ret = __internal_accept4 (fd, addr, addr_len, flags);
  58       /* The kernel returns -EINVAL for unknown socket operations.
  59          We need to convert that error to an ENOSYS error.  */
  60       if (__builtin_expect (ret < 0, 0)
  61           && have_accept4 == 0
  62           && errno == EINVAL)
  63         {
  64           /* Try another call, this time with the FLAGS parameter
  65              cleared and an invalid file descriptor.  This call will not
  66              cause any harm and it will return immediately.  */
  67           ret = __internal_accept4 (-1, addr, addr_len, 0);
  68           if (errno == EINVAL)
  69             {
  70               have_accept4 = -1;
  71               __set_errno (ENOSYS);
  72             }
  73           else
  74             {
  75               have_accept4 = 1;
  76               __set_errno (EINVAL);
  77             }
  78           return -1;
  79         }
  80       return ret;
  81     }
  82   __set_errno (ENOSYS);
  83   return -1;
  84 }
  85 # else
  86 /* When __ASSUME_ACCEPT4 accept4 is defined in internal_accept4.S.  */
  87 # endif
  88 #else
  89 int
  90 accept4 (int fd, __SOCKADDR_ARG addr, socklen_t *addr_len, int flags)
  91 {
  92   __set_errno (ENOSYS);
  93   return -1;
  94 }
  95 stub_warning (accept4)
  96 #endif