GDB: error detected on stdin

GDB: error detected on stdin

[Vikash Jain]

Hi All,

I'm trying to pipe commands to gdb but I get the following messages.
Will it cause any problems? How do i resolve the same?

(gdb) Hangup detected on fd 0
error detected on stdin

Python Script
============
#!/usr/local/bin/python
import subprocess

proc=subprocess.Popen('gdb',shell=True,stdin=su
bprocess.PIPE,stdout=subprocess.PIPE,executable="/usr/local/bin/bash")
proc.stdin.write('help')
output=proc.communicate()[0]
print output

Script Log
==========
[XXX@test ~/CAT/example]$ python -u main.py
GNU gdb (GDB) 7.2.50.20110328-cvs
Copyright (C) 2011 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "i386-unknown-freebsd6.3".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
(gdb) Hangup detected on fd 0
error detected on stdin

Best Regards
Vikash Jain

Re: GDB: error detected on stdin

[Andreas Schwab]

Vikash Jain <vikashjin@gmail.com> writes:

> I'm trying to pipe commands to gdb but I get the following messages.
> Will it cause any problems? How do i resolve the same?

2011-05-24  Andreas Schwab  <schwab@redhat.com>

	* event-loop.c (handle_file_event): Don't handle POLLHUP as error.

--- event-loop.c.~1.49.~	2011-03-22 11:59:52.000000000 +0100
+++ event-loop.c	2011-05-24 16:27:28.614311098 +0200
@@ -759,7 +759,6 @@ handle_file_event (event_data data)
   int mask;
 #ifdef HAVE_POLL
   int error_mask;
-  int error_mask_returned;
 #endif
   int event_file_desc = data.integer;
 
@@ -783,22 +782,19 @@ handle_file_event (event_data data)
 	  if (use_poll)
 	    {
 #ifdef HAVE_POLL
+	      /* POLLHUP means EOF, but can be combined with POLLIN to
+		 signal more data to read.  */
 	      error_mask = POLLHUP | POLLERR | POLLNVAL;
-	      mask = (file_ptr->ready_mask & file_ptr->mask) |
-		(file_ptr->ready_mask & error_mask);
-	      error_mask_returned = mask & error_mask;
+	      mask = file_ptr->ready_mask & (file_ptr->mask | error_mask);
 
-	      if (error_mask_returned != 0)
+	      if ((mask & (POLLERR | POLLNVAL)) != 0)
 		{
 		  /* Work in progress.  We may need to tell somebody
 		     what kind of error we had.  */
-		  if (error_mask_returned & POLLHUP)
-		    printf_unfiltered (_("Hangup detected on fd %d\n"),
-				       file_ptr->fd);
-		  if (error_mask_returned & POLLERR)
+		  if (mask & POLLERR)
 		    printf_unfiltered (_("Error detected on fd %d\n"),
 				       file_ptr->fd);
-		  if (error_mask_returned & POLLNVAL)
+		  if (mask & POLLNVAL)
 		    printf_unfiltered (_("Invalid or non-`poll'able fd %d\n"),
 				       file_ptr->fd);
 		  file_ptr->error = 1;

Andreas.

-- 
Andreas Schwab, schwab@redhat.com
GPG Key fingerprint = D4E8 DBE3 3813 BB5D FA84  5EC7 45C6 250E 6F00 984E
"And now for something completely different."

Re: GDB: error detected on stdin

[Tom Tromey]

>>>>> "Andreas" == Andreas Schwab <schwab@redhat.com> writes:

Andreas> 2011-05-24  Andreas Schwab  <schwab@redhat.com>
Andreas> 	* event-loop.c (handle_file_event): Don't handle POLLHUP as error.

This is ok.  IIRC this fixes some PR as well.

Tom

Re: GDB: error detected on stdin

[Andreas Schwab]

Tom Tromey <tromey@redhat.com> writes:

>>>>>> "Andreas" == Andreas Schwab <schwab@redhat.com> writes:
>
> Andreas> 2011-05-24  Andreas Schwab  <schwab@redhat.com>
> Andreas> 	* event-loop.c (handle_file_event): Don't handle POLLHUP as error.
>
> This is ok.  IIRC this fixes some PR as well.

Yep, it's 8677.

Andreas.

-- 
Andreas Schwab, schwab@redhat.com
GPG Key fingerprint = D4E8 DBE3 3813 BB5D FA84  5EC7 45C6 250E 6F00 984E
"And now for something completely different."

Re: GDB: error detected on stdin

[Vikash Jain]

Thanks a lot, fix worked for me.

On Wed, May 25, 2011 at 1:29 PM, Andreas Schwab <schwab@redhat.com> wrote:
> Tom Tromey <tromey@redhat.com> writes:
>
>>>>>>> "Andreas" == Andreas Schwab <schwab@redhat.com> writes:
>>
>> Andreas> 2011-05-24  Andreas Schwab  <schwab@redhat.com>
>> Andreas>      * event-loop.c (handle_file_event): Don't handle POLLHUP as error.
>>
>> This is ok.  IIRC this fixes some PR as well.
>
> Yep, it's 8677.
>
> Andreas.
>
> --
> Andreas Schwab, schwab@redhat.com
> GPG Key fingerprint = D4E8 DBE3 3813 BB5D FA84  5EC7 45C6 250E 6F00 984E
> "And now for something completely different."
>