OpenSSL and multi-threads

I will just put this code here. It is not panacea, as it doesn’t deal with FreeBSD, but it is helpful in most cases when all you need is to support Windows and and say Debian. Of course, the clean solution assumes usage of CRYPTO_THREADID_* family introduced recently. (to give an idea, it has a CRYPTO_THREADID_cmp callback, which can be mapped to pthread_equal)

#include <pthread.h>
#include <openssl/err.h>

#if defined(WIN32)
    #define MUTEX_TYPE            HANDLE
    #define MUTEX_SETUP(x)        (x) = CreateMutex(NULL, FALSE, NULL)
    #define MUTEX_CLEANUP(x)      CloseHandle(x)
    #define MUTEX_LOCK(x)         WaitForSingleObject((x), INFINITE)
    #define MUTEX_UNLOCK(x)       ReleaseMutex(x)
    #define THREAD_ID             GetCurrentThreadId()
#else
    #define MUTEX_TYPE            pthread_mutex_t
    #define MUTEX_SETUP(x)        pthread_mutex_init(&(x), NULL)
    #define MUTEX_CLEANUP(x)      pthread_mutex_destroy(&(x))
    #define MUTEX_LOCK(x)         pthread_mutex_lock(&(x))
    #define MUTEX_UNLOCK(x)       pthread_mutex_unlock(&(x))
    #define THREAD_ID             pthread_self()
#endif

/* This array will store all of the mutexes available to OpenSSL. */ 
static MUTEX_TYPE *mutex_buf=NULL;

static void locking_function(int mode, int n, const char * file, int line)
{
    if (mode & CRYPTO_LOCK)
        MUTEX_LOCK(mutex_buf[n]);
    else
        MUTEX_UNLOCK(mutex_buf[n]);
}

static unsigned long id_function(void)
{
    return ((unsigned long)THREAD_ID);
}

int thread_setup(void)
{
    int i;

    mutex_buf = malloc(CRYPTO_num_locks() * sizeof(MUTEX_TYPE));
    if (!mutex_buf)
        return 0;
    for (i = 0;  i < CRYPTO_num_locks(  );  i++)
        MUTEX_SETUP(mutex_buf[i]);
    CRYPTO_set_id_callback(id_function);
    CRYPTO_set_locking_callback(locking_function);
    return 1;
}

int thread_cleanup(void)
{
    int i;
    if (!mutex_buf)
        return 0;
    CRYPTO_set_id_callback(NULL);
    CRYPTO_set_locking_callback(NULL);
    for (i = 0;  i < CRYPTO_num_locks(  );  i++)
        MUTEX_CLEANUP(mutex_buf[i]);
    free(mutex_buf);
    mutex_buf = NULL;
    return 1;
}