/******************************************************************************
*
* Copyright © International Business Machines Corp., 2006-2008
*
* 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 2 of the License, or
* (at your option) any later version.
*
* DESCRIPTION
* This test exercises the futex_wait_requeue_pi() signal handling both
* before and after the requeue. The first should be restarted by the
* kernel. The latter should return EWOULDBLOCK to the waiter.
*
* AUTHORS
* Darren Hart <dvhart@linux.intel.com>
*
* HISTORY
* 2008-May-5: Initial version by Darren Hart <dvhart@linux.intel.com>
*
*****************************************************************************/
#include <errno.h>
#include <getopt.h>
#include <limits.h>
#include <pthread.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "atomic.h"
#include "futextest.h"
#include "logging.h"
#define DELAY_US 100
futex_t f1 = FUTEX_INITIALIZER;
futex_t f2 = FUTEX_INITIALIZER;
atomic_t requeued = ATOMIC_INITIALIZER;
int waiter_ret = 0;
void usage(char *prog)
{
printf("Usage: %s\n", prog);
printf(" -c Use color\n");
printf(" -h Display this help message\n");
printf(" -v L Verbosity level: %d=QUIET %d=CRITICAL %d=INFO\n",
VQUIET, VCRITICAL, VINFO);
}
int create_rt_thread(pthread_t *pth, void*(*func)(void *), void *arg,
int policy, int prio)
{
struct sched_param schedp;
pthread_attr_t attr;
int ret;
pthread_attr_init(&attr);
memset(&schedp, 0, sizeof(schedp));
ret = pthread_attr_setinheritsched(&attr, PTHREAD_EXPLICIT_SCHED);
if (ret) {
error("pthread_attr_setinheritsched\n", ret);
return -1;
}
ret = pthread_attr_setschedpolicy(&attr, policy);
if (ret) {
error("pthread_attr_setschedpolicy\n", ret);
return -1;
}
schedp.sched_priority = prio;
ret = pthread_attr_setschedparam(&attr, &schedp);
if (ret) {
error("pthread_attr_setschedparam\n", ret);
return -1;
}
ret = pthread_create(pth, &attr, func, arg);
if (ret) {
error("pthread_create\n", ret);
return -1;
}
return 0;
}
void handle_signal(int signo)
{
info("signal received %s requeue\n",
requeued.val ? "after" : "prior to");
}
void *waiterfn(void *arg)
{
unsigned int old_val;
int res;
waiter_ret = RET_PASS;
info("Waiter running\n");
info("Calling FUTEX_LOCK_PI on f2=%x @ %p\n", f2, &f2);
old_val = f1;
res = futex_wait_requeue_pi(&f1, old_val, &(f2), NULL,
FUTEX_PRIVATE_FLAG);
if (!requeued.val || errno != EWOULDBLOCK) {
fail("unexpected return from futex_wait_requeue_pi: %d (%s)\n",
res, strerror(errno));
info("w2:futex: %x\n", f2);
if (!res)
futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
waiter_ret = RET_FAIL;
}
info("Waiter exiting with %d\n", waiter_ret);
pthread_exit(NULL);
}
int main(int argc, char *argv[])
{
unsigned int old_val;
struct sigaction sa;
pthread_t waiter;
int c, res, ret = RET_PASS;
while ((c = getopt(argc, argv, "chv:")) != -1) {
switch (c) {
case 'c':
log_color(1);
break;
case 'h':
usage(basename(argv[0]));
exit(0);
case 'v':
log_verbosity(atoi(optarg));
break;
default:
usage(basename(argv[0]));
exit(1);
}
}
printf("%s: Test signal handling during requeue_pi\n",
basename(argv[0]));
printf("\tArguments: <none>\n");
sa.sa_handler = handle_signal;
sigemptyset(&sa.sa_mask);
sa.sa_flags = 0;
if (sigaction(SIGUSR1, &sa, NULL)) {
error("sigaction\n", errno);
exit(1);
}
info("m1:f2: %x\n", f2);
info("Creating waiter\n");
res = create_rt_thread(&waiter, waiterfn, NULL, SCHED_FIFO, 1);
if (res) {
error("Creating waiting thread failed", res);
ret = RET_ERROR;
goto out;
}
info("Calling FUTEX_LOCK_PI on f2=%x @ %p\n", f2, &f2);
info("m2:f2: %x\n", f2);
futex_lock_pi(&f2, 0, 0, FUTEX_PRIVATE_FLAG);
info("m3:f2: %x\n", f2);
while (1) {
/*
* signal the waiter before requeue, waiter should automatically
* restart futex_wait_requeue_pi() in the kernel. Wait for the
* waiter to block on f1 again.
*/
info("Issuing SIGUSR1 to waiter\n");
pthread_kill(waiter, SIGUSR1);
usleep(DELAY_US);
info("Requeueing waiter via FUTEX_CMP_REQUEUE_PI\n");
old_val = f1;
res = futex_cmp_requeue_pi(&f1, old_val, &(f2), 1, 0,
FUTEX_PRIVATE_FLAG);
/*
* If res is non-zero, we either requeued the waiter or hit an
* error, break out and handle it. If it is zero, then the
* signal may have hit before the the waiter was blocked on f1.
* Try again.
*/
if (res > 0) {
atomic_set(&requeued, 1);
break;
} else if (res < 0) {
error("FUTEX_CMP_REQUEUE_PI failed\n", errno);
ret = RET_ERROR;
break;
}
}
info("m4:f2: %x\n", f2);
/*
* Signal the waiter after requeue, waiter should return from
* futex_wait_requeue_pi() with EWOULDBLOCK. Join the thread here so the
* futex_unlock_pi() can't happen before the signal wakeup is detected
* in the kernel.
*/
info("Issuing SIGUSR1 to waiter\n");
pthread_kill(waiter, SIGUSR1);
info("Waiting for waiter to return\n");
pthread_join(waiter, NULL);
info("Calling FUTEX_UNLOCK_PI on mutex=%x @ %p\n", f2, &f2);
futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
info("m5:f2: %x\n", f2);
out:
if (ret == RET_PASS && waiter_ret)
ret = waiter_ret;
print_result(ret);
return ret;
}
