Original Redmine Comment
Author Name: Stefan Tauner (@stefanct)
Original Date: 2015-04-28T15:27:14Z

The problem is that @errno@ is never reset in @VPreProcImp::readWholefile()@.
In my application - for whatever reason - @errno@ is already set to @EAGAIN@ before the @while(!eof)@ loop, so the current implementation obviously will loop forever:

     while (!eof) {
         todo = INFILTER_IPC_BUFSIZ;
         got = read (fd, buf, todo);
         if (got>0) {
             outl.push_back(string(buf, got));
         }
         else if (errno == EINTR || errno == EAGAIN
#ifdef EWOULDBLOCK
	     || errno == EWOULDBLOCK
#endif
             ) {
         } else { eof = true; break; }
     }

Resetting @errno@ anywhere in the loop will fix my problem and potentially others. I have added @errno = 0;@ to the empty @else if@ branch and that works fine, apart from pointlessly reading 0 bytes after the end of file. Normally I would suggest to use a counter to accumulate the total number of bytes read and compare that to the file size... but since you apparently support piping in gzipped file via popen this will of course not work. Cheers!

Original Redmine Comment
Author Name: Wilson Snyder (@wsnyder)
Original Date: 2015-04-28T16:47:09Z

Can you check that setting errno = 0 just before the read() call solves your problem?

Original Redmine Comment
Author Name: Stefan Tauner (@stefanct)
Original Date: 2015-04-28T19:39:40Z

It does. However, doing it outside the loop keeps the whole construct erroneous. Think about the following scenario:

1. A legal @READ()@ gets interrupted by an external signal (and hence sets @errno=EINTR@).
2. The loop continues until the end of the file and thus @READ()@ begins to return 0 at each call
3. Because @errno@ is never cleared the loop will never end, just like in my case but for a different reason

So I strongly discourage from just resetting it before the loop. It will fix the bug I experienced but will not make the loop correct.

Original Redmine Comment
Author Name: Wilson Snyder (@wsnyder)
Original Date: 2015-04-28T19:43:49Z

Sorry, I said just before the read, not before the loop. This.

     while (!eof) {
         todo = INFILTER_IPC_BUFSIZ;
         errno = 0;  //<<<<<<<<<<<<<<<<<<<<
         got = read (fd, buf, todo);
         if (got>0) {
             outl.push_back(string(buf, got));
         }
         else if (errno == EINTR || errno == EAGAIN
#ifdef EWOULDBLOCK
          || errno == EWOULDBLOCK
#endif
             ) {
         } else { eof = true; break; }
     }

Original Redmine Comment
Author Name: Stefan Tauner (@stefanct)
Original Date: 2015-04-28T19:46:44Z

Right, sorry! This fixes it of course (too), thanks.

Original Redmine Comment
Author Name: Wilson Snyder (@wsnyder)
Original Date: 2015-04-28T19:52:09Z

Fixed in git towards 3.413. Thanks much for diagnosing this so well.

Original Redmine Comment
Author Name: Wilson Snyder (@wsnyder)
Original Date: 2015-06-26T10:30:32Z

In 3.414.