include/babeltrace/compat/send.h

   1 #ifndef _BABELTRACE_COMPAT_SEND_H
   2 #define _BABELTRACE_COMPAT_SEND_H
   3
   4 /*
   5  * babeltrace/compat/send.h
   6  *
   7  * Copyright (C) 2015  Michael Jeanson <mjeanson@efficios.com>
   8  *
   9  * Permission is hereby granted, free of charge, to any person obtaining a copy
  10  * of this software and associated documentation files (the "Software"), to deal
  11  * in the Software without restriction, including without limitation the rights
  12  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  13  * copies of the Software, and to permit persons to whom the Software is
  14  * furnished to do so, subject to the following conditions:
  15  *
  16  * The above copyright notice and this permission notice shall be included in
  17  * all copies or substantial portions of the Software.
  18  *
  19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  20  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  21  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  22  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  23  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  24  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  25  * SOFTWARE.
  26  */
  27
  28 /*
  29  * This wrapper is used on platforms that have no way of ignoring SIGPIPE
  30  * during a send(). Instead, we set the signal action to ignore. This is OK
  31  * in a single-threaded app, but would be problematic in a multi-threaded app
  32  * since sigaction applies to all threads.
  33  */
  34
  35 #ifndef MSG_NOSIGNAL
  36 # ifdef SO_NOSIGPIPE
  37 #   define MSG_NOSIGNAL SO_NOSIGPIPE
  38 # endif
  39 #endif
  40
  41 #if defined(MSG_NOSIGNAL)
  42 static inline
  43 ssize_t bt_send_nosigpipe(int fd, const void *buffer, size_t size)
  44 {
  45         return send(fd, buffer, size, MSG_NOSIGNAL);
  46 }
  47 #else
  48 static inline
  49 ssize_t bt_send_nosigpipe(int fd, const void *buffer, size_t size)
  50 {
  51         ssize_t sent;
  52         int saved_err;
  53         struct sigaction act, oldact;
  54
  55         /* Set SIGPIPE action to ignore and save current signal action */
  56         act.sa_handler = SIG_IGN;
  57         if (sigaction(SIGPIPE, &act, &oldact)) {
  58                 perror("sigaction");
  59                 sent = -1;
  60                 goto end;
  61         }
  62
  63         /* Send and save errno */
  64         sent = send(fd, buffer, size, 0);
  65         saved_err = errno;
  66
  67         /* Restore original signal action */
  68         if (sigaction(SIGPIPE, &oldact, NULL)) {
  69                 perror("sigaction");
  70                 sent = -1;
  71                 goto end;
  72         }
  73
  74         /* Restore send() errno */
  75         errno = saved_err;
  76 end:
  77         return sent;
  78 }
  79 #endif
  80
  81 #endif /* _BABELTRACE_COMPAT_SEND_H */