foomatic-rip: Fix a SIGPIPE error when calling gs (#517)

https://autopkgtest.ubuntu.com/packages/f/foo2zjs/lunar/ppc64el shows
foo2zjs's testsuite failing with cups-filters 2.0beta3 on ppc64el because
the gs command here to check page count is failing with a SIGPIPE when
trying to write back to the parent.  To fix this, we close gs's input fd as
soon as we know we're done writing to it.  Since gs may not have started
processing its input until this happens, also give the final poll() a longer
timeout (5s instead of 1s); without this we see race conditions because
foomatic-rip gives up before gs has had a chance to finish processing.

diff --git a/filter/foomatic-rip/postscript.c b/filter/foomatic-rip/postscript.c
index e6fbd2ac0aa384643db8c228f10758d4fe970d82..a7bbf895d76d5e4b34f1b08482a0dfff51476f88 100644 (file)
--- a/filter/foomatic-rip/postscript.c
+++ b/filter/foomatic-rip/postscript.c
@@ -277,13 +277,17 @@ print_ps(FILE *file,
       }
     }
 
+    fclose(in);
+
     // If the input file has only a single page and the "showpage" is
     // very close to the end of the file, it cannot have been
     // discovered after the last bits of input data got
     // read. Therefore we do an extra check here.
     if (!pagefound)
     {
-      pres = poll(&pfd, 1, 1000);
+      // gs may have only started processing after we closed the input fd
+      // above, so give it a generous timeout.
+      pres = poll(&pfd, 1, 5000);
       if (pres < 0)
        _log("Error reading Ghostscript output\n");
       else if (pres && (pfd.revents & POLLIN))
@@ -291,7 +295,6 @@ print_ps(FILE *file,
     }
 
     // Clean up and make Ghostscript stop by that
-    fclose(in);
     fclose(out);
     wait_for_process(pid);