/*
 * Copyright 2026, Haiku, Inc. All rights reserved.
 * Distributed under the terms of the MIT License.
 */

#include <OS.h>
#include <fs_attr.h>
#include <TypeConstants.h>
#include <pthread.h>


/*! This test tries to reproduce races between file_cache_read and
        file_cache_set_size. If the file_cache can't discard busy pages, or fails
        to recheck the cache size, then this can result in various deadlocks or
        assertion failures. */


const char* tmpfile = "__file";


static void*
writer(void* _data)
{
        rename_thread(find_thread(NULL), "writer");

        int fd = *(int*)_data;
        char buffer[2048];

        while (true) {
                ftruncate(fd, 0);
                pwrite(fd, buffer, sizeof(buffer), 0);

                // re-open the file with NOCACHE to evict all pages from the cache
                int nocached = open(tmpfile, O_RDWR | O_NOCACHE);
                close(nocached);
        }

        return NULL;
}


static void*
reader(void* _data)
{
        rename_thread(find_thread(NULL), "reader");

        int fd = *(int*)_data;

        char buffer[1];
        while (true)
                pread(fd, &buffer, sizeof(buffer), 1);

        return NULL;
}


int
main()
{
        int file = open(tmpfile, O_CREAT | O_TRUNC | O_RDWR);
        if (file < 0)
                return -1;

        pthread_t threads[2];
        pthread_create(&threads[0], NULL, writer, &file);
        pthread_create(&threads[1], NULL, reader, &file);

        pthread_join(threads[0], NULL);

        return 0;
}