[GUACAMOLE-1115] RDP print process may hang

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 1.1.0
• Fix Version/s: 1.5.0
• Component/s: guacamole-server
• Assignee: Mike Jumper
• Reporter: Jimmy
• Created: 26/Jun/20 15:33
• Updated: 11/Jan/23 00:18
• Resolved: 17/Mar/22 19:23

Description

I found the printing problem that locks up the entire session and produces the disconnect.

When connecting the Windows 2010 and printing the document in Microsoft Word, I encountered this problem.

This problem isn't always produced and it's sometimes produced.

 

So, I have analyzed the printing part of the guacamole server project.

I have found the following issue:

If guac_rdp_print_job_set_state() function is called after guac_rdp_print_job_wait_for_ack() call, this produces the lock of the entire session.

 

static void guac_rdp_print_job_set_state(guac_rdp_print_job* job,
        guac_rdp_print_job_state state) {

    pthread_mutex_lock(&(job->state_lock));

    /* Update stream state, signalling modification */
    job->state = state;
    pthread_cond_signal(&(job->state_modified));

    pthread_mutex_unlock(&(job->state_lock));
}

  

static int guac_rdp_print_job_wait_for_ack(guac_rdp_print_job* job) {

    /* Wait for ack if stream open and not yet received */
    pthread_mutex_lock(&(job->state_lock));
    if (job->state == GUAC_RDP_PRINT_JOB_WAITING_FOR_ACK)
        pthread_cond_wait(&job->state_modified, &job->state_lock);

    /* Reset state if ack received */
    int got_ack = (job->state == GUAC_RDP_PRINT_JOB_ACK_RECEIVED);
    if (got_ack)
        job->state = GUAC_RDP_PRINT_JOB_WAITING_FOR_ACK;

    /* Return whether ack was successfully received */
    pthread_mutex_unlock(&(job->state_lock));
    return got_ack;
}

  

I think that this issue can produce a printing problem and a lock of the entire session.

Please let me know whether my thought is correct.

 

Thanks.

 

Issue Links

• is duplicated by: GUACAMOLE-1684 Guacamole Freezes when printing
• is duplicated by: GUACAMOLE-1354 Printing problem that freezes the guacd