sysdeps/unix/sysv/linux/recvmmsg.c

   1 /* Copyright (C) 2010-2016 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           struct timespec *tmo)
  39 {
  40   return SYSCALL_CANCEL (recvmmsg, fd, vmessages, vlen, flags, tmo);
  41 }
  42 #elif defined __NR_socketcall
  43 # include <socketcall.h>
  44 # ifdef __ASSUME_RECVMMSG_SOCKETCALL
  45 int
  46 recvmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags,
  47           struct timespec *tmo)
  48 {
  49   return SOCKETCALL_CANCEL (recvmmsg, fd, vmessages, vlen, flags, tmo);
  50 }
  51 # else
  52 static int have_recvmmsg;
  53
  54 int
  55 recvmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags,
  56           struct timespec *tmo)
  57 {
  58   if (__glibc_likely (have_recvmmsg >= 0))
  59     {
  60       int ret = SOCKETCALL_CANCEL (recvmmsg, fd, vmessages, vlen, flags,
  61                                    tmo);
  62       /* The kernel returns -EINVAL for unknown socket operations.
  63          We need to convert that error to an ENOSYS error.  */
  64       if (__builtin_expect (ret < 0, 0)
  65           && have_recvmmsg == 0
  66           && errno == EINVAL)
  67         {
  68           /* Try another call, this time with an invalid file
  69              descriptor and all other parameters cleared.  This call
  70              will not cause any harm and it will return
  71              immediately.  */
  72           ret = SOCKETCALL_CANCEL (invalid, -1);
  73           if (errno == EINVAL)
  74             {
  75               have_recvmmsg = -1;
  76               __set_errno (ENOSYS);
  77             }
  78           else
  79             {
  80               have_recvmmsg = 1;
  81               __set_errno (EINVAL);
  82             }
  83           return -1;
  84         }
  85       return ret;
  86     }
  87   __set_errno (ENOSYS);
  88   return -1;
  89 }
  90 # endif /* __ASSUME_RECVMMSG_SOCKETCALL  */
  91 #else
  92 # include <socket/recvmmsg.c>
  93 #endif