compiler-rt/test/tsan/Linux/epoll_norace.cpp

   1 // RUN: %clangxx_tsan -O1 %s -o %t && %run %t 2>&1 | FileCheck %s
   2
   3 // The test captures what some high-performance networking servers do.
   4 // One thread writes to an fd, and another just receives an epoll
   5 // notification about the write to synchronize with the first thread
   6 // w/o actually reading from the fd.
   7
   8 #include "../test.h"
   9 #include <errno.h>
  10 #include <sys/epoll.h>
  11 #include <sys/eventfd.h>
  12
  13 int main() {
  14   int efd = epoll_create(1);
  15   if (efd == -1)
  16     exit(printf("epoll_create failed: %d\n", errno));
  17   int fd = eventfd(0, 0);
  18   if (fd == -1)
  19     exit(printf("eventfd failed: %d\n", errno));
  20   epoll_event event = {.events = EPOLLIN | EPOLLET};
  21   if (epoll_ctl(efd, EPOLL_CTL_ADD, fd, &event))
  22     exit(printf("epoll_ctl failed: %d\n", errno));
  23   pthread_t th;
  24   pthread_create(
  25       &th, nullptr,
  26       +[](void *arg) -> void * {
  27         long long to_add = 1;
  28         if (write((long)arg, &to_add, sizeof(to_add)) != sizeof(to_add))
  29           exit(printf("write failed: %d\n", errno));
  30         return nullptr;
  31       },
  32       (void *)(long)fd);
  33   struct epoll_event events[1] = {};
  34   if (epoll_wait(efd, events, 1, -1) != 1)
  35     exit(printf("epoll_wait failed: %d\n", errno));
  36   close(fd);
  37   pthread_join(th, nullptr);
  38   close(efd);
  39   fprintf(stderr, "DONE\n");
  40 }
  41
  42 // CHECK: DONE