sysdeps/unix/sysv/linux/recvmmsg.c

   1 /* Copyright (C) 2010-2014 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Andreas Schwab <schwab@redhat.com>, 2010.
   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_recvmmsg
  28 int
  29 recvmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags,
  30           const struct timespec *tmo)
  31 {
  32   if (SINGLE_THREAD_P)
  33     return INLINE_SYSCALL (recvmmsg, 5, fd, vmessages, vlen, flags, tmo);
  34
  35   int oldtype = LIBC_CANCEL_ASYNC ();
  36
  37   int result = INLINE_SYSCALL (recvmmsg, 5, fd, vmessages, vlen, flags, tmo);
  38
  39   LIBC_CANCEL_RESET (oldtype);
  40
  41   return result;
  42 }
  43 #elif defined __NR_socketcall
  44 # ifndef __ASSUME_RECVMMSG
  45 extern int __internal_recvmmsg (int fd, struct mmsghdr *vmessages,
  46                                 unsigned int vlen, int flags,
  47                                 const struct timespec *tmo)
  48      attribute_hidden;
  49
  50 static int have_recvmmsg;
  51
  52 int
  53 recvmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags,
  54           const struct timespec *tmo)
  55 {
  56   if (__builtin_expect (have_recvmmsg >= 0, 1))
  57     {
  58       int ret = __internal_recvmmsg (fd, vmessages, vlen, flags, tmo);
  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_recvmmsg == 0
  63           && errno == EINVAL)
  64         {
  65           /* Try another call, this time with an invalid file
  66              descriptor and all other parameters cleared.  This call
  67              will not cause any harm and it will return
  68              immediately.  */
  69           ret = __internal_recvmmsg (-1, 0, 0, 0, 0);
  70           if (errno == EINVAL)
  71             {
  72               have_recvmmsg = -1;
  73               __set_errno (ENOSYS);
  74             }
  75           else
  76             {
  77               have_recvmmsg = 1;
  78               __set_errno (EINVAL);
  79             }
  80           return -1;
  81         }
  82       return ret;
  83     }
  84   __set_errno (ENOSYS);
  85   return -1;
  86 }
  87 # else
  88 /* When __ASSUME_RECVMMSG recvmmsg is defined in internal_recvmmsg.S.  */
  89 # endif
  90 #else
  91 # include <socket/recvmmsg.c>
  92 #endif