| 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 | /* We generate children 3 levels deep */ |
| 48 | #define FORK_DEPTH 3 |
| 49 | /* Each generation spawns 10 children */ |
| 50 | #define NR_FORK 10 |
| 51 | |
| 52 | static int fork_generation; |
| 53 | |
| 54 | struct test_node { |
| 55 | int somedata; |
| 56 | struct rcu_head head; |
| 57 | }; |
| 58 | |
| 59 | static void cb(struct rcu_head *head) |
| 60 | { |
| 61 | struct test_node *node; |
| 62 | |
| 63 | fprintf(stderr, "rcu callback invoked in pid: %d\n", |
| 64 | (int) getpid()); |
| 65 | node = caa_container_of(head, struct test_node, head); |
| 66 | free(node); |
| 67 | } |
| 68 | |
| 69 | static void test_rcu(void) |
| 70 | { |
| 71 | struct test_node *node; |
| 72 | |
| 73 | rcu_register_thread(); |
| 74 | |
| 75 | synchronize_rcu(); |
| 76 | |
| 77 | rcu_read_lock(); |
| 78 | rcu_read_unlock(); |
| 79 | |
| 80 | node = malloc(sizeof(*node)); |
| 81 | assert(node); |
| 82 | |
| 83 | call_rcu(&node->head, cb); |
| 84 | |
| 85 | synchronize_rcu(); |
| 86 | |
| 87 | rcu_unregister_thread(); |
| 88 | } |
| 89 | |
| 90 | /* |
| 91 | * Return 0 if child, > 0 if parent, < 0 on error. |
| 92 | */ |
| 93 | static int do_fork(const char *execname) |
| 94 | { |
| 95 | pid_t pid; |
| 96 | |
| 97 | fprintf(stderr, "%s parent pid: %d, before fork\n", |
| 98 | execname, (int) getpid()); |
| 99 | |
| 100 | call_rcu_before_fork(); |
| 101 | pid = fork(); |
| 102 | if (pid == 0) { |
| 103 | /* child */ |
| 104 | fork_generation++; |
| 105 | |
| 106 | call_rcu_after_fork_child(); |
| 107 | fprintf(stderr, "%s child pid: %d, after fork\n", |
| 108 | execname, (int) getpid()); |
| 109 | test_rcu(); |
| 110 | fprintf(stderr, "%s child pid: %d, after rcu test\n", |
| 111 | execname, (int) getpid()); |
| 112 | if (fork_generation >= FORK_DEPTH) |
| 113 | exit(EXIT_SUCCESS); |
| 114 | return 0; |
| 115 | } else if (pid > 0) { |
| 116 | int status; |
| 117 | |
| 118 | /* parent */ |
| 119 | call_rcu_after_fork_parent(); |
| 120 | fprintf(stderr, "%s parent pid: %d, after fork\n", |
| 121 | execname, (int) getpid()); |
| 122 | test_rcu(); |
| 123 | fprintf(stderr, "%s parent pid: %d, after rcu test\n", |
| 124 | execname, (int) getpid()); |
| 125 | for (;;) { |
| 126 | pid = wait(&status); |
| 127 | if (pid < 0) { |
| 128 | perror("wait"); |
| 129 | return -1; |
| 130 | } |
| 131 | if (WIFEXITED(status)) { |
| 132 | fprintf(stderr, "child %u exited normally with status %u\n", |
| 133 | pid, WEXITSTATUS(status)); |
| 134 | if (WEXITSTATUS(status)) |
| 135 | return -1; |
| 136 | break; |
| 137 | } else if (WIFSIGNALED(status)) { |
| 138 | fprintf(stderr, "child %u was terminated by signal %u\n", |
| 139 | pid, WTERMSIG(status)); |
| 140 | return -1; |
| 141 | } else { |
| 142 | continue; |
| 143 | } |
| 144 | } |
| 145 | return 1; |
| 146 | } else { |
| 147 | perror("fork"); |
| 148 | return -1; |
| 149 | } |
| 150 | } |
| 151 | |
| 152 | int main(int argc, char **argv) |
| 153 | { |
| 154 | unsigned int i; |
| 155 | |
| 156 | #if 0 |
| 157 | /* pthread_atfork does not work with malloc/free in callbacks */ |
| 158 | ret = pthread_atfork(call_rcu_before_fork, |
| 159 | call_rcu_after_fork_parent, |
| 160 | call_rcu_after_fork_child); |
| 161 | if (ret) { |
| 162 | errno = ret; |
| 163 | perror("pthread_atfork"); |
| 164 | exit(EXIT_FAILURE); |
| 165 | } |
| 166 | #endif |
| 167 | |
| 168 | restart: |
| 169 | for (i = 0; i < NR_FORK; i++) { |
| 170 | int ret; |
| 171 | |
| 172 | test_rcu(); |
| 173 | synchronize_rcu(); |
| 174 | ret = do_fork(argv[0]); |
| 175 | if (ret == 0) /* child */ |
| 176 | goto restart; |
| 177 | else if (ret < 0) |
| 178 | goto error; |
| 179 | /* else parent, continue. */ |
| 180 | } |
| 181 | exit(EXIT_SUCCESS); |
| 182 | |
| 183 | error: |
| 184 | exit(EXIT_FAILURE); |
| 185 | } |