sysdeps/unix/sysv/linux/sendmmsg.c

   1 /* Copyright (C) 2011-2015 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 /* Do not use the sendmmsg 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_SENDMMSG_SYSCALL_WITH_SOCKETCALL \
  31     && !defined __ASSUME_SENDMMSG_SYSCALL
  32 # undef __NR_sendmmsg
  33 #endif
  34
  35 #ifdef __NR_sendmmsg
  36 int
  37 __sendmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags)
  38 {
  39   if (SINGLE_THREAD_P)
  40     return INLINE_SYSCALL (sendmmsg, 4, fd, vmessages, vlen, flags);
  41
  42   int oldtype = LIBC_CANCEL_ASYNC ();
  43
  44   int result = INLINE_SYSCALL (sendmmsg, 4, fd, vmessages, vlen, flags);
  45
  46   LIBC_CANCEL_RESET (oldtype);
  47
  48   return result;
  49 }
  50 libc_hidden_def (__sendmmsg)
  51 weak_alias (__sendmmsg, sendmmsg)
  52 #elif defined __NR_socketcall
  53 # include <socketcall.h>
  54 # ifdef __ASSUME_SENDMMSG_SOCKETCALL
  55 int
  56 __sendmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags)
  57 {
  58   return SOCKETCALL_CANCEL (sendmmsg, fd, vmessages, vlen, flags);
  59 }
  60 # else
  61 static int have_sendmmsg;
  62
  63 int
  64 __sendmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags)
  65 {
  66   if (__glibc_likely (have_sendmmsg >= 0))
  67     {
  68       int ret = SOCKETCALL_CANCEL (sendmmsg, fd, vmessages, vlen, flags);
  69       /* The kernel returns -EINVAL for unknown socket operations.
  70          We need to convert that error to an ENOSYS error.  */
  71       if (__builtin_expect (ret < 0, 0)
  72           && have_sendmmsg == 0
  73           && errno == EINVAL)
  74         {
  75           /* Try another call, this time with an invalid file
  76              descriptor and all other parameters cleared.  This call
  77              will not cause any harm and it will return
  78              immediately.  */
  79           ret = SOCKETCALL_CANCEL (invalid, -1);
  80           if (errno == EINVAL)
  81             {
  82               have_sendmmsg = -1;
  83               __set_errno (ENOSYS);
  84             }
  85           else
  86             {
  87               have_sendmmsg = 1;
  88               __set_errno (EINVAL);
  89             }
  90           return -1;
  91         }
  92       return ret;
  93     }
  94   __set_errno (ENOSYS);
  95   return -1;
  96 }
  97 # endif /* __ASSUME_SENDMMSG_SOCKETCALL  */
  98 libc_hidden_def (__sendmmsg)
  99 weak_alias (__sendmmsg, sendmmsg)
 100 #else
 101 # include <socket/sendmmsg.c>
 102 #endif