RE: 1.7.9: mq_unlink/mq_open leaks handles

RE: 1.7.9: mq_unlink/mq_open leaks handles

[Manuel Wienand]

Grmpf,

sorry for the spam. Just realized that mq_close is still needed, even if we don't want to open the queue again.
mq_unlink just deletes the file while mq_close frees the resources of the mqd_t struct.

Manuel


> -----Original Message-----
> Sent: Monday, April 04, 2011 2:50 PM
> Subject: 1.7.9: mq_unlink/mq_open leaks handles
> 
> Hallo,
> 
> it seems that mq_unlink and/or mq_open forget to close some handles (5
> to be precise).
> How to test:
> Execute the following code and watch the number of handles in the
> windows task-manager (processes tab, you can add a column there). For
> me it increases by 5 with every loop.
> 
> Tested with this DLL: cygwin1-20110327.dll
> 
> Thanks,
> 
> Manuel
> 
> 
> 
> 
> #include <stdio.h>
> #include <stdlib.h>
> #include <mqueue.h>
> #include <string.h>
> #include <errno.h>
> #include <fcntl.h>
> #include <unistd.h>
> 
> int main(void)
> {
>   int res;
>   int i = 0;
>   char msgQueueTestName[] = "./testQueue";
>   mqd_t testQueue;
>   struct mq_attr  attrQueue;
>   memset(&attrQueue,0x00,sizeof(attrQueue));
>   attrQueue.mq_maxmsg  = 10;  /* room for X messages in the queue */
>   attrQueue.mq_msgsize = 20;  /* maximum size of a message */
> 
>   while(1)
>   {
>     sleep(1);
>     i++;
>     printf("Loop #%d\n", i); fflush(stdout);
> 
>     // Remove old queues before trying to create a new one.
>     res = mq_unlink(msgQueueTestName);
>     if ((res == -1) && (errno != ENOENT))
>     {
>       // Don't print anything if the queue can't be unlinked, because
> it doesn't exist.
>      printf("Failed to unlink msg queue %s: %s %d\n", msgQueueTestName,
> sys_errlist[errno],errno);
>     }
> 
>     testQueue = mq_open(msgQueueTestName, O_RDWR | O_CREAT | O_EXCL,
> S_IRWXU | S_IRWXG, &attrQueue);
>     if( testQueue == (mqd_t)-1 )
>     {
>       printf("Failed to open msg queue %s: %s %d\n", msgQueueTestName,
> sys_errlist[errno],errno);
>     }
> 
>     res = mq_unlink(msgQueueTestName);
>     if (res == -1)
>     {
>       printf("Failed to unlink msg queue %s: %s %d\n",
> msgQueueTestName, sys_errlist[errno],errno);
>     }
>   }
> 
> 	return EXIT_SUCCESS;
> }

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1.7.9: mq_unlink/mq_open leaks handles

[Manuel Wienand]

Hallo,

it seems that mq_unlink and/or mq_open forget to close some handles (5 to be precise).
How to test:
Execute the following code and watch the number of handles in the windows task-manager (processes tab, you can add a column there). For me it increases by 5 with every loop.

Tested with this DLL: cygwin1-20110327.dll

Thanks,

Manuel




#include <stdio.h>
#include <stdlib.h>
#include <mqueue.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>

int main(void)
{
  int res;
  int i = 0;
  char msgQueueTestName[] = "./testQueue";
  mqd_t testQueue;
  struct mq_attr  attrQueue;
  memset(&attrQueue,0x00,sizeof(attrQueue));
  attrQueue.mq_maxmsg  = 10;  /* room for X messages in the queue */
  attrQueue.mq_msgsize = 20;  /* maximum size of a message */

  while(1)
  {
    sleep(1);
    i++;
    printf("Loop #%d\n", i); fflush(stdout);

    // Remove old queues before trying to create a new one.
    res = mq_unlink(msgQueueTestName);
    if ((res == -1) && (errno != ENOENT))
    {
      // Don't print anything if the queue can't be unlinked, because it doesn't exist.
     printf("Failed to unlink msg queue %s: %s %d\n", msgQueueTestName, sys_errlist[errno],errno);
    }

    testQueue = mq_open(msgQueueTestName, O_RDWR | O_CREAT | O_EXCL, S_IRWXU | S_IRWXG, &attrQueue);
    if( testQueue == (mqd_t)-1 )
    {
      printf("Failed to open msg queue %s: %s %d\n", msgQueueTestName, sys_errlist[errno],errno);
    }

    res = mq_unlink(msgQueueTestName);
    if (res == -1)
    {
      printf("Failed to unlink msg queue %s: %s %d\n", msgQueueTestName, sys_errlist[errno],errno);
    }
  }

	return EXIT_SUCCESS;
}


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