compiler-rt/test/tsan/vfork.cpp

   1 // RUN: %clangxx_tsan -O1 %s -o %t && %run %t 2>&1 | FileCheck %s
   2 // UNSUPPORTED: ios
   3
   4 #include <pthread.h>
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <unistd.h>
   8 #include <sys/types.h>
   9
  10 int fds[2];
  11 int X;
  12
  13 void *Thread1(void *x) {
  14   X = 42;
  15   write(fds[1], "a", 1);
  16   return NULL;
  17 }
  18
  19 void *Thread2(void *x) {
  20   char buf;
  21   while (read(fds[0], &buf, 1) != 1) {
  22   }
  23   X = 43;
  24   return NULL;
  25 }
  26
  27 int main() {
  28   pipe(fds);
  29   int pid = vfork();
  30   if (pid < 0) {
  31     fprintf(stderr, "FAIL to vfork\n");
  32     exit(1);
  33   }
  34   if (pid == 0) {  // child
  35     // Closing of fds must not affect parent process.
  36     // Strictly saying this is undefined behavior, because vfork child is not
  37     // allowed to call any functions other than exec/exit. But this is what
  38     // openjdk does.
  39     close(fds[0]);
  40     close(fds[1]);
  41     _exit(0);
  42   }
  43   pthread_t t[2];
  44   pthread_create(&t[0], NULL, Thread1, NULL);
  45   pthread_create(&t[1], NULL, Thread2, NULL);
  46   pthread_join(t[0], NULL);
  47   pthread_join(t[1], NULL);
  48   fprintf(stderr, "DONE\n");
  49 }
  50
  51 // CHECK-NOT: WARNING: ThreadSanitizer: data race
  52 // CHECK-NOT: FAIL to vfork
  53 // CHECK: DONE