multi-threaded "libssh2_init()" about libssh2 HOT 12 CLOSED

#ifdef LIBSSH_USES_OPENSSL
    CRYPTO_set_id_callback(thread_id);
    CRYPTO_set_locking_callback(lock_callback);
#else 
    gcry_control (GCRYCTL_SET_THREAD_CBS, &gcry_threads_pthread);
    gnutls_global_init();
#endif
libssh2_init(0);

gcry_control (GCRYCTL_SET_THREAD_CBS, &gcry_threads_pthread);

info threads
  7 Thread 0x7f3f0665c700 (LWP 26756)  0x0000003abf8e13b3 in select () at syscall-template.S:82
  6 Thread 0x7f3f0705d700 (LWP 26752)  0x0000003abf8e13b3 in select () at syscall-template.S:82
  5 Thread 0x7f3f07a5e700 (LWP 26750)  0x0000003abf8e13b3 in select () at syscall-template.S:82
  4 Thread 0x7f3f0f43c700 (LWP 26603)  0x0000003abf8e8f33 in epoll_wait () at syscall-template.S:82
  3 Thread 0x7f3f356ca820 (LWP 26602)  pthread_cond_wait@@GLIBC_2.3.2 () at pthread_cond_wait.S:183
  2 Thread 0x7f3f0e743700 (LWP 26649)  0x0000003abf8e13b3 in select () at syscall-template.S:82
* 1 Thread 0x7f3ef3fff700 (LWP 26803)  sha1_block_data_order_avx () at sha1-x86_64.s:3392

#0  sha1_block_data_order_avx () at sha1-x86_64.s:3392
#1  0xca62c1d6ca62c1d6 in ?? ()
#2  0xca62c1d6ca62c1d6 in ?? ()
#3  0xca62c1d6ca62c1d6 in ?? ()
#4  0xca62c1d6ca62c1d6 in ?? ()
#5  0xca62c1d6ca62c1d6 in ?? ()
#6  0xca62c1d6ca62c1d6 in ?? ()
#7  0xca62c1d6ca62c1d6 in ?? ()
#8  0xca62c1d6ca62c1d6 in ?? ()
#9  0x0000003ac9fdf7f8 in state () from libcrypto.so.1.0.1e
#10 0x00007f3eec07eff0 in ?? ()
#11 0x0000000000000027 in ?? () at stl_tree.h:874
#12 0x0000003ac9c72d67 in SHA1_Update (c=0xa670dc42, data_=<value optimized out>, len=<value optimized out>) at md32_common.h:325
#13 0x0000003ac9ce62e4 in ssleay_rand_bytes (
    buf=0x7f3eec01b82b "\325(2[...]", <incomplete sequence \347>, num=0, pseudo=0) at md_rand.c:477
#14 0x0000003acc01a61c in _libssh2_transport_send (session=0x7f3eec0175a0, data=0x7f3eec024d0c "^", data_len=<value optimized out>, data2=0x7f3eec07faa4 "", data2_len=<value optimized out>)
    at transport.c:818
#15 0x0000003acc006469 in _libssh2_channel_write (channel=0x7f3eec024aa0, stream_id=0, buf=0x7f3eec07faa4 "", buflen=<value optimized out>) at channel.c:2058
#16 0x0000003acc015e5c in sftp_read (hnd=0x7f3eec024ec0, buffer=0x7f3ef3fcdf90 "\270\"\b\354>\177", buffer_maxlen=504) at sftp.c:1405
#17 libssh2_sftp_read (hnd=0x7f3eec024ec0, buffer=0x7f3ef3fcdf90 "\270\"\b\354>\177", buffer_maxlen=504) at sftp.c:1568

static void init_multithreaded();
static void exit_multithreaded();

static int _libssh2_initialized = 0;
static int _libssh2_init_flags = 0;

LIBSSH2_API int
libssh2_init(int flags)
{
    if (_libssh2_initialized == 0 && !(flags & LIBSSH2_INIT_NO_CRYPTO)) {
        if (flags & LIBSSH2_INIT_MULTITHREADED)
            init_multithreaded();
        libssh2_crypto_init();
        _libssh2_init_aes_ctr();
    }

    _libssh2_initialized++;
    _libssh2_init_flags |= flags;

    return 0;
}

LIBSSH2_API void
libssh2_exit(void)
{
    if (_libssh2_initialized == 0)
        return;

    _libssh2_initialized--;

    if (!(_libssh2_init_flags & LIBSSH2_INIT_NO_CRYPTO)) {
        libssh2_crypto_exit();
        if (flags & LIBSSH2_INIT_MULTITHREADED)
            exit_multithreaded();
    }

    return;
}


#ifdef LIBSSH2_MULTITHREADED

#ifdef LIBSSH2_OPENSSL
#include <pthread.h>
static unsigned long crypto_thread_id()
{
    return (unsigned long)thread_id();
}
static pthread_mutex_t *lockarray = NULL;
static void crypto_lock_callback( int mode, int type, const char *file, int line )
{
    ASSERT( lockarray != NULL );
    if( mode & CRYPTO_LOCK )
        pthread_mutex_lock( &(lockarray[type]) );
    else
        pthread_mutex_unlock( &(lockarray[type]) );
}
static void init_multithreaded()
{
    ASSERT( lockarray == NULL );
    lockarray = (pthread_mutex_t *) malloc( CRYPTO_num_locks() * sizeof(pthread_mutex_t) );
    for( int i=0; i < CRYPTO_num_locks(); ++i )
        pthread_mutex_init( &(lockarray[i]), NULL );
    CRYPTO_set_id_callback( crypto_thread_id );
    CRYPTO_set_locking_callback( crypto_lock_callback );
}
static void exit_multithreaded()
{
    // kill locks
    if( lockarray == NULL )
        return ;
    CRYPTO_set_locking_callback( NULL );
    for( int i=0; i < CRYPTO_num_locks(); ++i )
        pthread_mutex_destroy( &(lockarray[i]) );
    free( lockarray );
    lockarray = NULL;

    ENGINE_cleanup();
    CRYPTO_cleanup_all_ex_data();
    ERR_free_strings();
    ERR_remove_state(0);
    EVP_cleanup();
}    

#elif defined(LIBSSH2_LIBGCRYPT)

GCRY_THREAD_OPTION_PTHREAD_IMPL;
static void init_multithreaded()
{
    gcry_control( GCRYCTL_SET_THREAD_CBS );
}
static void exit_multithreaded()
{
}

#elif defined(LIBSSH2_WINCNG)

static void init_multithreaded()
{
}
static void exit_multithreaded()
{
}

#endif

#else

static void init_multithreaded()
{
}
static void exit_multithreaded()
{
}

#endif