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/* SPDX-License-Identifier: GPL-2.0-or-later */
#ifndef _FUTEX_THREAD_H
#define _FUTEX_THREAD_H
#include <errno.h>
#include <pthread.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include "kselftest_harness.h"
#define USEC_PER_SEC 1000000L
#define WAIT_FOR_THREAD_SECS 1
#define WAIT_FOR_THREAD_USECS (WAIT_FOR_THREAD_SECS * USEC_PER_SEC)
#define WAIT_THREAD_RETRIES 100
struct futex_thread {
pthread_t thread;
pthread_barrier_t barrier;
pid_t tid;
int (*threadfn)(void *arg);
void *arg;
int retval;
};
static inline int __wait_for_thread(FILE *fp, struct __test_metadata *_metadata)
{
unsigned int sleep_time_us = WAIT_FOR_THREAD_USECS / WAIT_THREAD_RETRIES;
char buf[80] = "";
for (int i = 0; i < WAIT_THREAD_RETRIES; i++) {
if (!fgets(buf, sizeof(buf), fp))
return EIO;
if (!strncmp(buf, "futex", 5))
return 0;
usleep(sleep_time_us);
rewind(fp);
}
TH_LOG("/proc/$PID/wchan contains \"%s\". Trying to continue.", buf);
return 0;
}
static void *__futex_thread_fn(void *arg)
{
struct futex_thread *t = arg;
t->tid = gettid();
pthread_barrier_wait(&t->barrier);
t->retval = t->threadfn(t->arg);
return NULL;
}
/**
* futex_wait_for_thread - Wait for the child thread to sleep in the futex context
* @t: Thread handle.
* @_metadata: Test metadata for TH_LOG() context
*/
static inline int futex_wait_for_thread(struct futex_thread *t, struct __test_metadata *_metadata)
{
char fname[80];
FILE *fp;
int res;
snprintf(fname, sizeof(fname), "/proc/%d/wchan", t->tid);
fp = fopen(fname, "r");
if (!fp) {
/* If /proc/... is not available, sleep */
if (errno != ENOENT)
return errno;
TH_LOG("/proc/$PID/wchan not accessible, continue with sleep()");
sleep(WAIT_FOR_THREAD_SECS);
return 0;
}
res = __wait_for_thread(fp, _metadata);
fclose(fp);
return res;
}
/**
* futex_thread_create - Create a new thread for testing.
* @t: The handle of the newly created thread.
* @threadfn: The new thread starts execution by invoking threadfn
* @arg: The parameters passed to threadfn.
*/
static inline int futex_thread_create(struct futex_thread *t, int (*threadfn)(void *), void *arg)
{
pthread_barrier_init(&t->barrier, NULL, 2);
t->tid = 0;
t->threadfn = threadfn;
t->arg = arg;
if (pthread_create(&t->thread, NULL, __futex_thread_fn, t) < 0) {
int ret = errno;
pthread_barrier_destroy(&t->barrier);
return ret;
}
pthread_barrier_wait(&t->barrier);
return 0;
}
/**
* futex_thread_destroy - Wait for and reclaim the resources of the thread.
* @t: Thread handle.
*/
static inline int futex_thread_destroy(struct futex_thread *t)
{
pthread_join(t->thread, NULL);
pthread_barrier_destroy(&t->barrier);
return t->retval;
}
#endif
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