ceph/src/jaegertracing/opentelemetry-cpp/sdk/test/common/random_fork_test.cc

   1 // Copyright The OpenTelemetry Authors
   2 // SPDX-License-Identifier: Apache-2.0
   3
   4 #ifdef __unix__
   5 // Verifies that IDs don't clash after forking the process.
   6 //
   7 // See https://github.com/opentracing-contrib/nginx-opentracing/issues/52
   8 #  include "src/common/random.h"
   9
  10 #  include <sys/mman.h>
  11 #  include <sys/types.h>
  12 #  include <sys/wait.h>
  13 #  include <unistd.h>
  14 #  include <cstdio>
  15 #  include <cstdlib>
  16 #  include <iostream>
  17 using opentelemetry::sdk::common::Random;
  18
  19 static uint64_t *child_id;
  20
  21 int main()
  22 {
  23   // Set up shared memory to communicate between parent and child processes.
  24   //
  25   // See https://stackoverflow.com/a/13274800/4447365
  26   child_id = static_cast<uint64_t *>(
  27       mmap(nullptr, sizeof(*child_id), PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0));
  28   *child_id = 0;
  29   if (fork() == 0)
  30   {
  31     *child_id = Random::GenerateRandom64();
  32     exit(EXIT_SUCCESS);
  33   }
  34   else
  35   {
  36     wait(nullptr);
  37     auto parent_id     = Random::GenerateRandom64();
  38     auto child_id_copy = *child_id;
  39     munmap(static_cast<void *>(child_id), sizeof(*child_id));
  40     if (parent_id == child_id_copy)
  41     {
  42       std::cerr << "Child and parent ids are the same value " << parent_id << "\n";
  43       return -1;
  44     }
  45   }
  46   return 0;
  47 }
  48 #else
  49 int main()
  50 {
  51   return 0;
  52 }
  53 #endif