sysdeps/unix/sysv/linux/sendmmsg.c

   1 /* Copyright (C) 2011-2014 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@gmail.com>, 2011.
   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 <sys/socket.h>
  21
  22 #include <sysdep-cancel.h>
  23 #include <sys/syscall.h>
  24 #include <kernel-features.h>
  25
  26
  27 #ifdef __NR_sendmmsg
  28 int
  29 __sendmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags)
  30 {
  31   if (SINGLE_THREAD_P)
  32     return INLINE_SYSCALL (sendmmsg, 4, fd, vmessages, vlen, flags);
  33
  34   int oldtype = LIBC_CANCEL_ASYNC ();
  35
  36   int result = INLINE_SYSCALL (sendmmsg, 4, fd, vmessages, vlen, flags);
  37
  38   LIBC_CANCEL_RESET (oldtype);
  39
  40   return result;
  41 }
  42 libc_hidden_def (__sendmmsg)
  43 weak_alias (__sendmmsg, sendmmsg)
  44 #elif defined __NR_socketcall
  45 # ifndef __ASSUME_SENDMMSG
  46 extern int __internal_sendmmsg (int fd, struct mmsghdr *vmessages,
  47                                 unsigned int vlen, int flags)
  48      attribute_hidden;
  49
  50 static int have_sendmmsg;
  51
  52 int
  53 __sendmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags)
  54 {
  55   if (__builtin_expect (have_sendmmsg >= 0, 1))
  56     {
  57       int ret = __internal_sendmmsg (fd, vmessages, vlen, 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_sendmmsg == 0
  62           && errno == EINVAL)
  63         {
  64           /* Try another call, this time with an invalid file
  65              descriptor and all other parameters cleared.  This call
  66              will not cause any harm and it will return
  67              immediately.  */
  68           ret = __internal_sendmmsg (-1, 0, 0, 0);
  69           if (errno == EINVAL)
  70             {
  71               have_sendmmsg = -1;
  72               __set_errno (ENOSYS);
  73             }
  74           else
  75             {
  76               have_sendmmsg = 1;
  77               __set_errno (EINVAL);
  78             }
  79           return -1;
  80         }
  81       return ret;
  82     }
  83   __set_errno (ENOSYS);
  84   return -1;
  85 }
  86 libc_hidden_def (__sendmmsg)
  87 weak_alias (__sendmmsg, sendmmsg)
  88 # else
  89 /* When __ASSUME_SENDMMSG sendmmsg is defined in internal_sendmmsg.S.  */
  90 # endif
  91 #else
  92 # include <socket/sendmmsg.c>
  93 #endif