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 /* Do not use the recvmmsg syscall on socketcall architectures unless
  27    it was added at the same time as the socketcall support or can be
  28    assumed to be present.  */
  29 #if defined __ASSUME_SOCKETCALL \
  30     && !defined __ASSUME_RECVMMSG_SYSCALL_WITH_SOCKETCALL \
  31     && !defined __ASSUME_RECVMMSG_SYSCALL
  32 # undef __NR_recvmmsg
  33 #endif
  34
  35 #ifdef __NR_recvmmsg
  36 int
  37 recvmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags,
  38           const struct timespec *tmo)
  39 {
  40   if (SINGLE_THREAD_P)
  41     return INLINE_SYSCALL (recvmmsg, 5, fd, vmessages, vlen, flags, tmo);
  42
  43   int oldtype = LIBC_CANCEL_ASYNC ();
  44
  45   int result = INLINE_SYSCALL (recvmmsg, 5, fd, vmessages, vlen, flags, tmo);
  46
  47   LIBC_CANCEL_RESET (oldtype);
  48
  49   return result;
  50 }
  51 #elif defined __NR_socketcall
  52 # ifndef __ASSUME_RECVMMSG_SOCKETCALL
  53 extern int __internal_recvmmsg (int fd, struct mmsghdr *vmessages,
  54                                 unsigned int vlen, int flags,
  55                                 const struct timespec *tmo)
  56      attribute_hidden;
  57
  58 static int have_recvmmsg;
  59
  60 int
  61 recvmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags,
  62           const struct timespec *tmo)
  63 {
  64   if (__glibc_likely (have_recvmmsg >= 0))
  65     {
  66       int ret = __internal_recvmmsg (fd, vmessages, vlen, flags, tmo);
  67       /* The kernel returns -EINVAL for unknown socket operations.
  68          We need to convert that error to an ENOSYS error.  */
  69       if (__builtin_expect (ret < 0, 0)
  70           && have_recvmmsg == 0
  71           && errno == EINVAL)
  72         {
  73           /* Try another call, this time with an invalid file
  74              descriptor and all other parameters cleared.  This call
  75              will not cause any harm and it will return
  76              immediately.  */
  77           ret = __internal_recvmmsg (-1, 0, 0, 0, 0);
  78           if (errno == EINVAL)
  79             {
  80               have_recvmmsg = -1;
  81               __set_errno (ENOSYS);
  82             }
  83           else
  84             {
  85               have_recvmmsg = 1;
  86               __set_errno (EINVAL);
  87             }
  88           return -1;
  89         }
  90       return ret;
  91     }
  92   __set_errno (ENOSYS);
  93   return -1;
  94 }
  95 # else
  96 /* When __ASSUME_RECVMMSG_SOCKETCALL recvmmsg is defined in
  97    internal_recvmmsg.S.  */
  98 # endif
  99 #else
 100 # include <socket/recvmmsg.c>
 101 #endif