sysdeps/unix/sysv/linux/recvmmsg.c

   1 /* Copyright (C) 2010-2015 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   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 # include <socketcall.h>
  53 # ifdef __ASSUME_RECVMMSG_SOCKETCALL
  54 int
  55 recvmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags,
  56           struct timespec *tmo)
  57 {
  58   return SOCKETCALL_CANCEL (recvmmsg, fd, vmessages, vlen, flags, tmo);
  59 }
  60 # else
  61 static int have_recvmmsg;
  62
  63 int
  64 recvmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags,
  65           struct timespec *tmo)
  66 {
  67   if (__glibc_likely (have_recvmmsg >= 0))
  68     {
  69       int ret = SOCKETCALL_CANCEL (recvmmsg, fd, vmessages, vlen, flags,
  70                                    tmo);
  71       /* The kernel returns -EINVAL for unknown socket operations.
  72          We need to convert that error to an ENOSYS error.  */
  73       if (__builtin_expect (ret < 0, 0)
  74           && have_recvmmsg == 0
  75           && errno == EINVAL)
  76         {
  77           /* Try another call, this time with an invalid file
  78              descriptor and all other parameters cleared.  This call
  79              will not cause any harm and it will return
  80              immediately.  */
  81           ret = SOCKETCALL_CANCEL (invalid, -1);
  82           if (errno == EINVAL)
  83             {
  84               have_recvmmsg = -1;
  85               __set_errno (ENOSYS);
  86             }
  87           else
  88             {
  89               have_recvmmsg = 1;
  90               __set_errno (EINVAL);
  91             }
  92           return -1;
  93         }
  94       return ret;
  95     }
  96   __set_errno (ENOSYS);
  97   return -1;
  98 }
  99 # endif /* __ASSUME_RECVMMSG_SOCKETCALL  */
 100 #else
 101 # include <socket/recvmmsg.c>
 102 #endif