[En-Nut-Discussion] File descriptor leak in 4.8.7

[Henrik Maier]

Hi Coleman,

Could the memory leak be caused by not closing the socket when _fdopen 
fails?

Henrik


On 5/05/2015 7:47 AM, Coleman Brumley wrote:
> After doing some arithmetic, it appears that each occurrence of "Creating
> stream device failed" causes a 1271 byte leak from heap space. Does that
> number ring a bell?
>
>
>
> I've re-verified that this does not happen unless a browser is making HTTP
> requests of the controller. If the controller is just "sitting there", there
> is no leak. I verify this via a printout of available heap space every 30
> minutes. After running for 4 hours, there were no leaks.
>
>
>
> While there is no set time between each occurrence, this does seem to happen
> about 5 times in 30 minutes.
>
>
>
> The errno value 23 means that too many files are open, correct? FOPEN_MAX is
> defined as 8, so is having six concurrent HTTP threads running too many? Is
> it possible that the use of multiple HTTP threads without using a mutex is
> causing the file open handles to corrupt somehow and therefore not be closed
> correctly?
>
>
>
> Coleman
>
>
>
> From: Coleman Brumley [mailto:cbrumley at polarsoft.biz]
> Sent: Monday, May 04, 2015 1:19 PM
> To: en-nut-discussion at egnite.de
> Subject: File descriptor leak in 4.8.7
>
>
>
> Everyone,
>
>
>
> I'm working with Nut/OS v4.8.7 (for many, many reasons, I CANNOT upgrade the
> core OS). The processor is an Atmel SAM7X256.
>
>
>
> I'm encountering a problem with the use of file descriptors in HTTP, and I
> believe the core effect is a resource leak.
>
>
>
> Here is my HTTP service code:
>
>
>
> THREAD(Service, arg)
>
> {
>
>         TCPSOCKET *sock;
>
>         FILE *stream;
>
>         u_char id = (u_char) ((uptr_t) arg);
>
>        u_char timeout=0;
>
>         time_t t;
>
>         struct _tm tmx ;
>
>         uint16_t lowheapcounter=1000;
>
> NutThreadSetPriority(72);
>
>
>
>      /*
>
>       * Now loop endless for connections.
>
>       */
>
>
>
>      for (;;) {
>
>
>
>          /*
>
>           * Create a socket.
>
>           */
>
>                if ((sock = NutTcpCreateSocket()) == 0)
>
>                {
>
>                       printf("[%u] Creating socket failed\n", id);
>
>                       NutSleep(5000);
>
>                       continue;
>
>                }
>
>          /*
>
>           * Listen on port 80. This call will block until we get a connection
>
>           * from a client.
>
>           */
>
>          NutTcpAccept(sock, 80);
>
>
>
>
>
>          /*
>
>           * Detect low heap and if it happens for too long, reset.
>
>           *
>
>           */
>
>                while (NutHeapAvailable() < 4096) {
>
>                       t=time(0l);
>
>                       localtime_r(&t,&tmx);
>
>                       printf("%02d:%02d:%02d %02d-%02d-%04d -- ",
>
>                             tmx.tm_hour,
>
>                             tmx.tm_min,
>
>                             tmx.tm_sec,
>
>                             tmx.tm_mon+1,
>
>                             tmx.tm_mday,
>
>                             tmx.tm_year+1900);
>
>                       printf("[%u] Low mem (%d)\n", id,
> (int)NutHeapAvailable());
>
>                       NutSleep(1000);
>
>                       lowheapcounter--;
>
>                       if(lowheapcounter<=0) Hreset();
>
>                }
>
>
>
>          /*
>
>           * Associate a stream with the socket so we can use standard I/O
> calls.
>
>           */
>
>
>
>                while (((stream = _fdopen((int) ((uptr_t) sock), "r+b")) ==
> 0)&&(++timeout<0xFF))
>
>                {
>
>                       NutSleep(10);
>
>                }
>
>                if(!stream)
>
>                {
>
>                       printf("\n[%u] Creating stream device failed w/
> errno:%d\n", id,errno);
>
> NutTcpCloseSocket(sock);
>
>                       continue;
>
>                }
>
>                else
>
>                {
>
>                       NutHttpProcessRequest(stream);
>
>                       fclose(stream);
>
>                       NutTcpCloseSocket(sock);
>
>                }
>
>      }
>
> }
>
>
>
> The console output shows all is normal initially, but after a while (approx.
> 765 seconds, initially after boot time) I start seeing"
>
>
>
> [3] Creating stream device failed w/ errno:23
>
>
>
> Where the number in braces is the thread id. I'm running 6 HTTP threads,
> started as follows:
>
> for (i = 1; i <= 6; i++)
>
> {
>
> char thname[] = "httpd0";
>
>          thname[5] = '0' + i;
>
>          NutThreadCreate(thname, Service, (void *) (uptr_t)
> i,HTTPD_SERVICE_STACK);
>
> }
>
>
>
> The stack size is defined as 1024.
>
>
>
> I noticed this question was asked some time ago on this list, but I could
> not determine if there was ever a solution posted. There are other I/O
> processes running in the controller, but it ONLY runs low on resources when
> a browser is connected to it.
>
>
>
> Does anyone have any suggestions as to what I could look into as to what
> might be the problem?
>
>
>
> While the browser(s) are connected, the system appears to lose about 4.5k of
> heap space per 30 minutes!
>
>
>
> Thanks in advance.
>
>
>
> Best Regards,
>
> Coleman
>
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