fd handling issues in start_job... #1559

michaelrsweet · 2006-04-12T20:53:00Z

Version: 1.2-current
CUPS.org User: jlovell

There seems to be two fd handling issues in start_job:

status fds need to be kept in cupsd_job_t since they are reused in multi-document jobs (and 'statusfds[1]' should only be closed after starting the last document).
'filterfds[slot]' should only be closed after starting the last document since they are copies of 'job->print_pipes'

These bugs manifest themselves by eventually causing select() to return EBADF.

This code is slightly tricky... I believe the attached patch is correct but please check.

Thanks!

michaelrsweet · 2006-04-14T18:01:35Z

CUPS.org User: mike

Looks pretty good, although we need to FD_CLR the status FD before calling cupsdClosePipe(), since that function resets the file descriptors to -1...

Also, the change introduced a file descriptor leak, which I'm tracking down now...

michaelrsweet · 2006-04-14T18:17:34Z

CUPS.org User: mike

Fixed in Subversion repository.

michaelrsweet · 2006-04-14T18:17:34Z

"start_job.patch":

Index: scheduler/job.c

--- scheduler/job.c (revision 5390)
+++ scheduler/job.c (working copy)
@@ -127,6 +127,8 @@
job->back_pipes[1] = -1;
job->print_pipes[0] = -1;
job->print_pipes[1] = -1;

job->status_pipes[0]= -1;
job->status_pipes[1]= -1;

cupsdSetString(&job->dest, dest);

@@ -442,15 +444,17 @@
*/

 cupsdLogMessage(CUPSD_LOG_DEBUG2,

      "cupsdFinishJob: Closing status pipes [ %d %d ]...",

      job->status_pipes[0], job->status_pipes[1]);

cupsdClosePipe(job->status_pipes);

cupsdLogMessage(CUPSD_LOG_DEBUG2,
"cupsdFinishJob: Removing fd %d from InputSet...",
job->status_buffer->fd);

FD_CLR(job->status_buffer->fd, InputSet);

cupsdLogMessage(CUPSD_LOG_DEBUG2,

               "cupsdFinishJob: Closing status input pipe %d...",

- job->status_buffer->fd);

 cupsdStatBufDelete(job->status_buffer);

 job->status_buffer = NULL;

@@ -1532,6 +1536,12 @@

cupsdClosePipe(job->back_pipes);

cupsdLogMessage(CUPSD_LOG_DEBUG2,

             "cupsdStopJob: Closing status pipes [ %d %d ]...",

             job->status_pipes[0], job->status_pipes[1]);

cupsdClosePipe(job->status_pipes);

if (job->status_buffer)
{
/*
@@ -1544,10 +1554,6 @@

FD_CLR(job->status_buffer->fd, InputSet);

cupsdLogMessage(CUPSD_LOG_DEBUG2,

               "cupsdStopJob: Closing status input pipe %d...",

- job->status_buffer->fd);

 cupsdStatBufDelete(job->status_buffer);

 job->status_buffer = NULL;

@@ -1979,6 +1985,8 @@
job->back_pipes[1] = -1;
job->print_pipes[0] = -1;
job->print_pipes[1] = -1;

```
 job->status_pipes[0]= -1;
```
```
 job->status_pipes[1]= -1;
```
cupsdLogMessage(CUPSD_LOG_DEBUG, "Loading job %d from cache...", job->id);
}
@@ -2227,6 +2235,8 @@
job->back_pipes[1] = -1;
job->print_pipes[0] = -1;
job->print_pipes[1] = -1;
```
 job->status_pipes[0]= -1;
```
```
 job->status_pipes[1]= -1;
```
if (job->id >= NextJobId)
NextJobId = job->id + 1;
@@ -2344,8 +2354,7 @@
int backroot; /* Run backend as root? /
int pid; / Process ID of new filter process /
int banner_page; / 1 if banner page, 0 otherwise */
int statusfds[2], /* Pipes used with the scheduler */

      filterfds[2][2];/\* Pipes used between filters */

int filterfds[2][2];/* Pipes used between filters /
int envc; / Number of environment variables _/
char *_argv, /* Filter command-line arguments /
sani_uri[1024], / Sanitized DEVICE_URI env var */
@@ -2992,32 +3001,31 @@
filterfds[1][0] = -1;
filterfds[1][1] = -1;
if (cupsdOpenPipe(statusfds))
if (job->status_pipes[0] == -1)
{
cupsdLogMessage(CUPSD_LOG_ERROR, "Unable to create job status pipes - %s.",
```
          strerror(errno));
```
snprintf(printer->state_message, sizeof(printer->state_message),

- "Unable to create status pipes - %s.", strerror(errno));

- cupsdAddPrinterHistory(printer);

cupsdAddEvent(CUPSD_EVENT_JOB_COMPLETED, job->printer, job,

             "Job canceled because the server could not create the job "

- "status pipes.");

goto abort_job;
if (cupsdOpenPipe(job->status_pipes))
{

 cupsdLogMessage(CUPSD_LOG_ERROR, "Unable to create job status pipes - %s.",

```
        strerror(errno));
```

 snprintf(printer->state_message, sizeof(printer->state_message),

     "Unable to create status pipes - %s.", strerror(errno));

```
 cupsdAddPrinterHistory(printer);
```

 cupsdAddEvent(CUPSD_EVENT_JOB_COMPLETED, job->printer, job,

      "Job canceled because the server could not create the job "

```
      "status pipes.");
```
```
 goto abort_job;
```
}
cupsdLogMessage(CUPSD_LOG_DEBUG2, "start_job: status_pipes = [ %d %d ]",

      job->status_pipes[0], job->status_pipes[1]);

job->status_buffer = cupsdStatBufNew(job->status_pipes[0], "[Job %d]",
```
                   job->id);
```
}
cupsdLogMessage(CUPSD_LOG_DEBUG2, "start_job: statusfds = [ %d %d ]",

- statusfds[0], statusfds[1]);

-#ifdef FD_CLOEXEC

fcntl(statusfds[0], F_SETFD, FD_CLOEXEC);
fcntl(statusfds[1], F_SETFD, FD_CLOEXEC);
-#endif /* FD_CLOEXEC */
job->status_buffer = cupsdStatBufNew(statusfds[0], "[Job %d]",

                                      job->id);

job->status = 0;
memset(job->filters, 0, sizeof(job->filters));

@@ -3144,7 +3152,7 @@
slot, filterfds[slot][0], filterfds[slot][1]);

 pid = cupsdStartProcess(command, argv, envp, filterfds[!slot][0],

                       filterfds[slot][1], statusfds[1],

```
                       filterfds[slot][1], job->status_pipes[1],
            job->back_pipes[0], 0, job->filters + i);
```
cupsdLogMessage(CUPSD_LOG_DEBUG2,
@@ -3232,7 +3240,7 @@
slot, filterfds[slot][0], filterfds[slot][1]);

pid = cupsdStartProcess(command, argv, envp, filterfds[!slot][0],

            filterfds[slot][1], statusfds[1],

            filterfds[slot][1], job->status_pipes[1],
          job->back_pipes[1], backroot,
          &(job->backend));

@@ -3271,6 +3279,13 @@
job->back_pipes[0], job->back_pipes[1]);

   cupsdClosePipe(job->back_pipes);

```
 cupsdLogMessage(CUPSD_LOG_DEBUG2,
```

        "start_job: Closing status output pipe %d...",

```
        job->status_pipes[1]);
```
```
 close(job->status_pipes[1]);
```
```
 job->status_pipes[1] = -1;
```
}
}
else
@@ -3278,13 +3293,6 @@
filterfds[slot][0] = -1;
filterfds[slot][1] = -1;
cupsdLogMessage(CUPSD_LOG_DEBUG2,

               "start_job: Closing filter pipes for slot %d "

```
      "[ %d %d ]...",
```

- !slot, filterfds[!slot][0], filterfds[!slot][1]);

- cupsdClosePipe(filterfds[!slot]);

 if (job->current_file == job->num_files)
 {
   cupsdLogMessage(CUPSD_LOG_DEBUG2,

@@ -3292,17 +3300,21 @@
job->print_pipes[0], job->print_pipes[1]);

   cupsdClosePipe(job->print_pipes);

```
 cupsdLogMessage(CUPSD_LOG_DEBUG2,
```

        "start_job: Closing status output pipe %d...",

```
        job->status_pipes[1]);
```
```
 close(job->status_pipes[1]);
```
```
 job->status_pipes[1] = -1;
```
}
}
for (slot = 0; slot < 2; slot ++)
{
cupsdLogMessage(CUPSD_LOG_DEBUG2,

               "start_job: Closing filter pipes for slot %d "

```
      "[ %d %d ]...",
```

               slot, filterfds[slot][0], filterfds[slot][1]);

cupsdClosePipe(filterfds[slot]);
}
cupsdLogMessage(CUPSD_LOG_DEBUG2,

    "start_job: Closing filter pipes for slot %d "

```
    "[ %d %d ]...",
```

    slot, filterfds[slot][0], filterfds[slot][1]);

cupsdClosePipe(filterfds[slot]);

if (remote_job)
{
@@ -3313,12 +3325,6 @@
free(argv);

cupsdLogMessage(CUPSD_LOG_DEBUG2,

             "start_job: Closing status output pipe %d...",

- statusfds[1]);

- close(statusfds[1]);

cupsdLogMessage(CUPSD_LOG_DEBUG2,
"start_job: Adding fd %d to InputSet...",
job->status_buffer->fd);

@@ -3348,8 +3354,8 @@

cupsdLogMessage(CUPSD_LOG_DEBUG2,
"start_job: Closing status pipes [ %d %d ]...",

             statusfds[0], statusfds[1]);

cupsdClosePipe(statusfds);

             job->status_pipes[0], job->status_pipes[1]);

cupsdClosePipe(job->status_pipes);

cupsArrayDelete(filters);

Index: scheduler/job.h

--- scheduler/job.h (revision 5390)
+++ scheduler/job.h (working copy)
@@ -46,7 +46,8 @@
ipp_t attrs; / Job attributes /
cupsd_statbuf_t *status_buffer; / Status buffer for this job /
int print_pipes[2], / Print data pipes */

      back_pipes[2];  /\* Backchannel pipes */

      back_pipes[2],  /\* Backchannel pipes */

```
      status_pipes[2];/\* Status pipes _/
```
int cost; /_ Filtering cost /
int filters[MAX_FILTERS + 1];
/ Filter process IDs, 0 terminated */

michaelrsweet closed this as completed Apr 14, 2006

michaelrsweet added the priority-high label Mar 17, 2016

michaelrsweet added this to the Stable milestone Mar 17, 2016

michaelrsweet mentioned this issue Mar 17, 2016

lpoptions entry "job-sheets=standard,none" prints job-sheet and hangs on printfile #1571

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fd handling issues in start_job... #1559

fd handling issues in start_job... #1559

michaelrsweet commented Apr 12, 2006

michaelrsweet commented Apr 14, 2006

michaelrsweet commented Apr 14, 2006

michaelrsweet commented Apr 14, 2006

fd handling issues in start_job... #1559

fd handling issues in start_job... #1559

Comments

michaelrsweet commented Apr 12, 2006

michaelrsweet commented Apr 14, 2006

michaelrsweet commented Apr 14, 2006

michaelrsweet commented Apr 14, 2006

Index: scheduler/job.c

- job->status_buffer->fd);

- job->status_buffer->fd);

- "Unable to create status pipes - %s.", strerror(errno));

- cupsdAddPrinterHistory(printer);

- "status pipes.");

- statusfds[0], statusfds[1]);

- !slot, filterfds[!slot][0], filterfds[!slot][1]);

- cupsdClosePipe(filterfds[!slot]);

- statusfds[1]);

- close(statusfds[1]);

Index: scheduler/job.h