tests/regression/test_urcu_fork.c

   1 /*
   2  * test_urcu_fork.c
   3  *
   4  * Userspace RCU library - test program (fork)
   5  *
   6  * Copyright February 2012 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along
  19  * with this program; if not, write to the Free Software Foundation, Inc.,
  20  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  21  */
  22
  23 #define _GNU_SOURCE
  24 #include "config.h"
  25 #include <stdio.h>
  26 #include <pthread.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <sys/types.h>
  30 #include <sys/wait.h>
  31 #include <unistd.h>
  32 #include <stdio.h>
  33 #include <assert.h>
  34 #include <sched.h>
  35 #include <errno.h>
  36
  37 #include <urcu/arch.h>
  38 #include <urcu/tls-compat.h>
  39
  40 #ifndef DYNAMIC_LINK_TEST
  41 #define _LGPL_SOURCE
  42 #else
  43 #define rcu_debug_yield_read()
  44 #endif
  45 #include <urcu.h>
  46
  47 #include "tap.h"
  48
  49 /* We generate children 3 levels deep */
  50 #define FORK_DEPTH      3
  51 /* Each generation spawns 10 children */
  52 #define NR_FORK         10
  53
  54 #define NR_TESTS        NR_FORK
  55
  56 static int fork_generation;
  57
  58 /*
  59  * Only print diagnostic for top level parent process, else the console
  60  * has trouble formatting the tap output.
  61  */
  62 #define diag_gen0(...) \
  63         do { \
  64                 if (!fork_generation) \
  65                         diag(__VA_ARGS__); \
  66         } while (0)
  67
  68 struct test_node {
  69         int somedata;
  70         struct rcu_head head;
  71 };
  72
  73 static void cb(struct rcu_head *head)
  74 {
  75         struct test_node *node;
  76
  77         diag_gen0("rcu callback invoked in pid: %d", (int) getpid());
  78         node = caa_container_of(head, struct test_node, head);
  79         free(node);
  80 }
  81
  82 static void test_rcu(void)
  83 {
  84         struct test_node *node;
  85
  86         rcu_register_thread();
  87
  88         synchronize_rcu();
  89
  90         rcu_read_lock();
  91         rcu_read_unlock();
  92
  93         node = malloc(sizeof(*node));
  94         assert(node);
  95
  96         call_rcu(&node->head, cb);
  97
  98         synchronize_rcu();
  99
 100         rcu_unregister_thread();
 101 }
 102
 103 /*
 104  * Return 0 if child, > 0 if parent, < 0 on error.
 105  */
 106 static int do_fork(const char *execname)
 107 {
 108         pid_t pid;
 109
 110         diag_gen0("%s parent pid: %d, before fork",
 111                 execname, (int) getpid());
 112
 113         call_rcu_before_fork();
 114         pid = fork();
 115         if (pid == 0) {
 116                 /* child */
 117                 fork_generation++;
 118                 tap_disable();
 119
 120                 call_rcu_after_fork_child();
 121                 diag_gen0("%s child pid: %d, after fork",
 122                         execname, (int) getpid());
 123                 test_rcu();
 124                 diag_gen0("%s child pid: %d, after rcu test",
 125                         execname, (int) getpid());
 126                 if (fork_generation >= FORK_DEPTH)
 127                         exit(EXIT_SUCCESS);
 128                 return 0;
 129         } else if (pid > 0) {
 130                 int status;
 131
 132                 /* parent */
 133                 call_rcu_after_fork_parent();
 134                 diag_gen0("%s parent pid: %d, after fork",
 135                         execname, (int) getpid());
 136                 test_rcu();
 137                 diag_gen0("%s parent pid: %d, after rcu test",
 138                         execname, (int) getpid());
 139                 for (;;) {
 140                         pid = wait(&status);
 141                         if (pid < 0) {
 142                                 if (!fork_generation)
 143                                         perror("wait");
 144                                 return -1;
 145                         }
 146                         if (WIFEXITED(status)) {
 147                                 diag_gen0("child %u exited normally with status %u",
 148                                         pid, WEXITSTATUS(status));
 149                                 if (WEXITSTATUS(status))
 150                                         return -1;
 151                                 break;
 152                         } else if (WIFSIGNALED(status)) {
 153                                 diag_gen0("child %u was terminated by signal %u",
 154                                         pid, WTERMSIG(status));
 155                                 return -1;
 156                         } else {
 157                                 continue;
 158                         }
 159                 }
 160                 return 1;
 161         } else {
 162                 if (!fork_generation)
 163                         perror("fork");
 164                 return -1;
 165         }
 166 }
 167
 168 int main(int argc, char **argv)
 169 {
 170         unsigned int i;
 171
 172         plan_tests(NR_TESTS);
 173
 174 #if 0
 175         /* pthread_atfork does not work with malloc/free in callbacks */
 176         ret = pthread_atfork(call_rcu_before_fork,
 177                 call_rcu_after_fork_parent,
 178                 call_rcu_after_fork_child);
 179         if (ret) {
 180                 errno = ret;
 181                 perror("pthread_atfork");
 182                 exit(EXIT_FAILURE);
 183         }
 184 #endif
 185
 186 restart:
 187         for (i = 0; i < NR_FORK; i++) {
 188                 int ret;
 189
 190                 test_rcu();
 191                 synchronize_rcu();
 192                 ret = do_fork(argv[0]);
 193                 if (!fork_generation) {
 194                         ok(ret >= 0, "child status %d", ret);
 195                 }
 196                 if (ret == 0) {         /* child */
 197                         goto restart;
 198                 } else if (ret < 0) {
 199                         goto error;
 200                 } else {
 201                         /* else parent, continue. */
 202                 }
 203         }
 204         if (!fork_generation) {
 205                 return exit_status();
 206         } else {
 207                 exit(EXIT_SUCCESS);
 208         }
 209
 210 error:
 211         if (!fork_generation) {
 212                 return exit_status();
 213         } else {
 214                 exit(EXIT_FAILURE);
 215         }
 216 }