tests/regression/tools/notification/default_pipe_size_getter.cpp

   1 /*
   2  * default_pipe_size_getter.c
   3  *
   4  * Tests suite for LTTng notification API (get default size of pipes)
   5  *
   6  * Copyright (C) 2021 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   7  *
   8  * SPDX-License-Identifier: MIT
   9  *
  10  */
  11
  12 #ifndef _GNU_SOURCE
  13 #define _GNU_SOURCE
  14 #endif
  15
  16 #include <unistd.h>
  17 #include <fcntl.h>
  18 #include <stdio.h>
  19 #include <stdlib.h>
  20
  21 #include <common/pipe.hpp>
  22 #include <common/error.hpp>
  23
  24 int lttng_opt_verbose;
  25 int lttng_opt_mi;
  26 int lttng_opt_quiet;
  27
  28 #ifdef __linux__
  29 /*
  30  * Return the default pipe buffer size or a negative error.
  31  */
  32 static
  33 int get_pipe_size(void)
  34 {
  35         int ret;
  36         /*
  37          * The event notifier pipes are not "special"; they are created using
  38          * the lttng_pipe utility. Hence, this should be representative of a
  39          * pipe created by the session daemon for event notifier messages to
  40          * go through.
  41          */
  42         struct lttng_pipe *pipe = lttng_pipe_open(0);
  43
  44         if (!pipe) {
  45                 /* lttng_pipe_open already logs on error. */
  46                 ret = -1;
  47                 goto end;
  48         }
  49
  50         ret = fcntl(lttng_pipe_get_writefd(pipe), F_GETPIPE_SZ);
  51         if (ret < 0) {
  52                 PERROR("Failed to get the size of the pipe");
  53         }
  54
  55         lttng_pipe_destroy(pipe);
  56 end:
  57         return ret;
  58 }
  59 #elif defined(__FreeBSD__)
  60 static
  61 int get_pipe_size(void)
  62 {
  63         return 65536;
  64 }
  65 #else
  66 #error "Implement get_pipe_size() for your platform."
  67 #endif
  68
  69 int main(void)
  70 {
  71         int ret;
  72
  73         ret = get_pipe_size();
  74         if (ret < 0) {
  75                 return EXIT_FAILURE;
  76         }
  77
  78         /* Print the pipe buffer size to stdout */
  79         printf("%d\n", ret);
  80
  81         return  EXIT_SUCCESS;
  82 }