sysdeps/unix/sysv/linux/accept4.c

   1 /* Copyright (C) 2008, 2009 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, 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 <signal.h>
  22 #include <sys/socket.h>
  23
  24 #include <sysdep-cancel.h>
  25 #include <sys/syscall.h>
  26 #include <kernel-features.h>
  27
  28
  29 #ifdef __NR_accept4
  30 int
  31 accept4 (int fd, __SOCKADDR_ARG addr, socklen_t *addr_len, int flags)
  32 {
  33   if (SINGLE_THREAD_P)
  34     return INLINE_SYSCALL (accept4, 4, fd, addr.__sockaddr__, addr_len, flags);
  35
  36   int oldtype = LIBC_CANCEL_ASYNC ();
  37
  38   int result = INLINE_SYSCALL (accept4, 4, fd, addr.__sockaddr__, addr_len,
  39                                flags);
  40
  41   LIBC_CANCEL_RESET (oldtype);
  42
  43   return result;
  44 }
  45 #elif defined __NR_socketcall
  46 # ifndef __ASSUME_ACCEPT4
  47 extern int __internal_accept4 (int fd, __SOCKADDR_ARG addr,
  48                                socklen_t *addr_len, int flags)
  49      attribute_hidden;
  50
  51 static int have_accept4;
  52
  53 int
  54 accept4 (int fd, __SOCKADDR_ARG addr, socklen_t *addr_len, int flags)
  55 {
  56   if (__builtin_expect (have_accept4 >= 0, 1))
  57     {
  58       int ret = __internal_accept4 (fd, addr, addr_len, flags);
  59       /* The kernel returns -EINVAL for unknown socket operations.
  60          We need to convert that error to an ENOSYS error.  */
  61       if (__builtin_expect (ret < 0, 0)
  62           && have_accept4 == 0
  63           && errno == EINVAL)
  64         {
  65           /* Try another call, this time with the FLAGS parameter
  66              cleared and an invalid file descriptor.  This call will not
  67              cause any harm and it will return immediately.  */
  68           ret = __internal_accept4 (-1, addr, addr_len, 0);
  69           if (errno == EINVAL)
  70             {
  71               have_accept4 = -1;
  72               __set_errno (ENOSYS);
  73             }
  74           else
  75             {
  76               have_accept4 = 1;
  77               __set_errno (EINVAL);
  78             }
  79           return -1;
  80         }
  81       return ret;
  82     }
  83   __set_errno (ENOSYS);
  84   return -1;
  85 }
  86 # else
  87 /* When __ASSUME_ACCEPT4 accept4 is defined in internal_accept4.S.  */
  88 # endif
  89 #else
  90 int
  91 accept4 (int fd, __SOCKADDR_ARG addr, socklen_t *addr_len, int flags)
  92 {
  93   __set_errno (ENOSYS);
  94   return -1;
  95 }
  96 stub_warning (accept4)
  97 #endif