--- /dev/null
+/*
+ Robust mutex test
+
+ Copyright (C) Amitay Isaacs 2016
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, see <http://www.gnu.org/licenses/>.
+*/
+
+/*
+ * Run this test as follows:
+ *
+ * 1. Running all processes at normal priority
+ *
+ * $ while true ; do ./bin/test_mutex_raw /tmp/foo 10 0 ; done
+ *
+ * 2. Running all processes at real-time priority
+ *
+ * # while true ; do ./bin/test_mutex_raw /tmp/foo 10 1 ; done
+ *
+ * The test will block after few iterations. At this time none of the
+ * child processes is holding the mutex.
+ *
+ * To check which process is holding a lock:
+ *
+ * $ ./bin/test_mutex_raw /tmp/foo debug
+ *
+ * If no pid is printed, then no process is holding the mutex.
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <inttypes.h>
+#include <sys/types.h>
+#include <sys/fcntl.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/wait.h>
+#include <sched.h>
+#include <sys/mman.h>
+#include <pthread.h>
+#include <errno.h>
+#include <stdbool.h>
+
+int pthread_mutex_consistent_np(pthread_mutex_t *);
+
+static void set_realtime(void)
+{
+ struct sched_param p;
+ int ret;
+
+ p.sched_priority = 1;
+
+ ret = sched_setscheduler(0, SCHED_FIFO, &p);
+ if (ret == -1) {
+ fprintf(stderr, "Failed to set scheduler to SCHED_FIFO\n");
+ }
+}
+
+static void high_priority(void)
+{
+ int ret;
+
+ ret = nice(-20);
+ if (ret == -1) {
+ fprintf(stderr, "Failed to set high priority\n");
+ }
+}
+
+static void run_child(const char *filename)
+{
+ pthread_mutex_t *mutex;
+ void *addr;
+ int ret, fd;
+
+ fd = open(filename, O_RDWR, 0600);
+ if (fd == -1) {
+ exit(1);
+ }
+
+ addr = mmap(NULL, sizeof(pthread_mutex_t), PROT_READ|PROT_WRITE,
+ MAP_SHARED|MAP_FILE, fd, 0);
+ if (addr == NULL) {
+ exit(2);
+ }
+
+ mutex = (pthread_mutex_t *)addr;
+
+again:
+ ret = pthread_mutex_lock(mutex);
+ if (ret == EOWNERDEAD) {
+ ret = pthread_mutex_consistent_np(mutex);
+ } else if (ret == EAGAIN) {
+ goto again;
+ }
+ if (ret != 0) {
+ fprintf(stderr, "pid %u lock failed, ret=%d\n", getpid(), ret);
+ exit(3);
+ }
+
+ fprintf(stderr, "pid %u locked\n", getpid());
+ kill(getpid(), SIGKILL);
+}
+
+#define PRIO_NORMAL 0
+#define PRIO_REALTIME 1
+#define PRIO_NICE_20 2
+
+int main(int argc, const char **argv)
+{
+ pthread_mutexattr_t ma;
+ pthread_mutex_t *mutex;
+ int fd, ret, i;
+ pid_t pid;
+ void *addr;
+ int num_children;
+ int priority = PRIO_NORMAL;
+
+ if (argc < 3 || argc > 4) {
+ fprintf(stderr, "Usage: %s <file> <n> [0|1|2]\n", argv[0]);
+ fprintf(stderr, " %s <file> debug\n", argv[0]);
+ exit(1);
+ }
+
+ if (argc == 4) {
+ priority = atoi(argv[3]);
+ }
+
+ if (priority == PRIO_REALTIME) {
+ set_realtime();
+ } else if (priority == PRIO_NICE_20) {
+ high_priority();
+ }
+
+ fd = open(argv[1], O_CREAT|O_RDWR, 0600);
+ if (fd == -1) {
+ fprintf(stderr, "open failed\n");
+ exit(1);
+ }
+
+ ret = lseek(fd, 0, SEEK_SET);
+ if (ret != 0) {
+ fprintf(stderr, "lseek failed\n");
+ exit(1);
+ }
+
+ ret = ftruncate(fd, sizeof(pthread_mutex_t));
+ if (ret != 0) {
+ fprintf(stderr, "ftruncate failed\n");
+ exit(1);
+ }
+
+ addr = mmap(NULL, sizeof(pthread_mutex_t), PROT_READ|PROT_WRITE,
+ MAP_SHARED|MAP_FILE, fd, 0);
+ if (addr == NULL) {
+ fprintf(stderr, "mmap failed\n");
+ exit(1);
+ }
+
+ mutex = (pthread_mutex_t *)addr;
+
+ if (strcmp(argv[2], "debug") == 0) {
+ ret = pthread_mutex_trylock(mutex);
+ if (ret == EOWNERDEAD) {
+ ret = pthread_mutex_consistent_np(mutex);
+ if (ret == 0) {
+ pthread_mutex_unlock(mutex);
+ }
+ } else if (ret == EBUSY) {
+ printf("pid=%u\n", mutex->__data.__owner);
+ } else if (ret == 0) {
+ pthread_mutex_unlock(mutex);
+ }
+ exit(0);
+ }
+
+ ret = pthread_mutexattr_init(&ma);
+ if (ret != 0) {
+ fprintf(stderr, "pthread_mutexattr_init failed\n");
+ exit(1);
+ }
+
+ ret = pthread_mutexattr_settype(&ma, PTHREAD_MUTEX_ERRORCHECK);
+ if (ret != 0) {
+ fprintf(stderr, "pthread_mutexattr_settype failed\n");
+ exit(1);
+ }
+
+ ret = pthread_mutexattr_setpshared(&ma, PTHREAD_PROCESS_SHARED);
+ if (ret != 0) {
+ fprintf(stderr, "pthread_mutexattr_setpshared failed\n");
+ exit(1);
+ }
+
+ ret = pthread_mutexattr_setrobust(&ma, PTHREAD_MUTEX_ROBUST);
+ if (ret != 0) {
+ fprintf(stderr, "pthread_mutexattr_setrobust failed\n");
+ exit(1);
+ }
+
+ ret = pthread_mutex_init(mutex, &ma);
+ if (ret != 0) {
+ fprintf(stderr, "pthread_mutex_init failed\n");
+ exit(1);
+ }
+
+ ret = pthread_mutex_lock(mutex);
+ if (ret != 0) {
+ fprintf(stderr, "pthread_mutex_lock failed\n");
+ exit(1);
+ }
+
+ setpgid(0, 0);
+
+ fprintf(stderr, "Creating children\n");
+ num_children = atoi(argv[2]);
+
+ for (i=0; i<num_children; i++) {
+ pid = fork();
+ if (pid < 0) {
+ fprintf(stderr, "fork() failed\n");
+ exit(1);
+ }
+ if (pid == 0) {
+ close(fd);
+ run_child(argv[1]);
+ exit(1);
+ }
+ }
+
+ fprintf(stderr, "Waiting for children\n");
+
+ ret = pthread_mutex_unlock(mutex);
+ if (ret != 0) {
+ fprintf(stderr, "pthread_mutex_unlock failed\n");
+ exit(1);
+ }
+
+ for (i=0; i<num_children; i++) {
+ int status;
+
+ pid = waitpid(-1, &status, 0);
+ if (pid <= 0) {
+ fprintf(stderr, "waitpid() failed\n");
+ }
+ }
+
+ close(fd);
+ unlink(argv[1]);
+ exit(0);
+}
git.samba.org / metze / samba / wip.git / commitdiff