tests/fuzz/fuzz_pthreads.c

/* **************************************************************
 * Copyright (c) 2015 Google, Inc.  All rights reserved.
 * **************************************************************/

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/* Test the Dr. Memory fuzzer on a multi-threaded app. */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <pthread.h>
#include <stdint.h>

#define NUM_THREADS 10
#define TEST_BUFFER "abcdefgh"
#define TEST_BUFFER_SIZE strlen(TEST_BUFFER)

typedef unsigned int uint;
typedef char byte;

void
print_buffer(byte *data, uint len, byte *counter, pthread_mutex_t *lock)
{
    uint i;
    char *buf;

    /* call something heavy like malloc to encourage thread interleaving */
    buf = malloc((len * 2/*per byte*/) + 1/*null-term*/);

    for (i = 0; i < len; i++)
        sprintf(buf + (i*2), "%02x", data[i] + *counter);

    pthread_mutex_lock(lock); /* lock to prevent linux kernel race on output streams */
    printf("%s\n", buf);      /* print the whole line to avoid character interleaving */
    pthread_mutex_unlock(lock);

    (*counter)++;
    free(buf);
}

void *
thread_main(void *arg)
{
    byte b = (byte) (intptr_t) arg;
    char *buffer = malloc(sizeof(TEST_BUFFER));
    pthread_mutex_t lock;

    pthread_mutex_init(&lock, NULL);

    strncpy(buffer, TEST_BUFFER, TEST_BUFFER_SIZE);
    print_buffer(buffer, TEST_BUFFER_SIZE, &b, &lock);

    pthread_mutex_destroy(&lock);
    free(buffer);
    return NULL;
}

int
main(int argc, char **argv)
{
    int i;
    void *retval;
    pthread_t thread[NUM_THREADS];

    for (i = 0; i < NUM_THREADS; i++) {
        if (pthread_create(&thread[i], NULL, thread_main, (void *)(intptr_t)i)) {
            fprintf(stderr, "failed to create thread #%d\n", i);
            exit(1);
        }
    }
    for (i = 0; i < NUM_THREADS; i++) {
        if (pthread_join(thread[i], &retval)) {
            fprintf(stderr, "failed to join thread #%d\n", i);
            exit(1);
        }
    }
    return 0;
}