[RFA] small patch to command_line_handler

[RFA] small patch to command_line_handler

[Martin M. Hunt]

Please check this carefully because I don't really understand the code here.

I'm trying to track down some memory trashing and random crashes and the 
command line handler is reading memory it didn't allocate, which is mostly 
harmless, but annoying and bad programming.  So here's a proposed fix.

-- 
Martin Hunt
GDB Engineer
Red Hat, Inc.

2002-06-07  Martin M. Hunt  <hunt@redhat.com>

	* event-top.c (command_line_handler): Don't read past
	beginning of buffer.

Index: event-top.c
===================================================================
RCS file: /cvs/src/src/gdb/event-top.c,v
retrieving revision 1.20
diff -u -u -r1.20 event-top.c
--- event-top.c	27 Mar 2002 21:20:15 -0000	1.20
+++ event-top.c	7 Jun 2002 20:08:32 -0000
@@ -681,7 +681,7 @@
 
   xfree (rl);			/* Allocated in readline.  */
 
-  if (*(p - 1) == '\\')
+  if (p > linebuffer && *(p - 1) == '\\')
     {
       p--;			/* Put on top of '\'.  */
 

Re: [RFA] small patch to command_line_handler

[Elena Zannoni]

Martin M. Hunt writes:
 > Please check this carefully because I don't really understand the code here.
 > 
 > I'm trying to track down some memory trashing and random crashes and the 
 > command line handler is reading memory it didn't allocate, which is mostly 
 > harmless, but annoying and bad programming.  So here's a proposed fix.
 > 

Hmmm, odd.  Martin, can you look at what happened to this thread that
reported the very same error? I thought this got fixed.

http://sources.redhat.com/ml/gdb-patches/2002-03/msg00533.html

Thanks
Elena


 > -- 
 > Martin Hunt
 > GDB Engineer
 > Red Hat, Inc.
 > 
 > 2002-06-07  Martin M. Hunt  <hunt@redhat.com>
 > 
 > 	* event-top.c (command_line_handler): Don't read past
 > 	beginning of buffer.
 > 
 > Index: event-top.c
 > ===================================================================
 > RCS file: /cvs/src/src/gdb/event-top.c,v
 > retrieving revision 1.20
 > diff -u -u -r1.20 event-top.c
 > --- event-top.c	27 Mar 2002 21:20:15 -0000	1.20
 > +++ event-top.c	7 Jun 2002 20:08:32 -0000
 > @@ -681,7 +681,7 @@
 >  
 >    xfree (rl);			/* Allocated in readline.  */
 >  
 > -  if (*(p - 1) == '\\')
 > +  if (p > linebuffer && *(p - 1) == '\\')
 >      {
 >        p--;			/* Put on top of '\'.  */
 >  

Re: [RFA] small patch to command_line_handler

[Martin M. Hunt]

On Friday 07 June 2002 02:51 pm, Elena Zannoni wrote:
> Martin M. Hunt writes:
>  > Please check this carefully because I don't really understand the code
>  > here.
>  >
>  > I'm trying to track down some memory trashing and random crashes and the
>  > command line handler is reading memory it didn't allocate, which is
>  > mostly harmless, but annoying and bad programming.  So here's a proposed
>  > fix.
>
> Hmmm, odd.  Martin, can you look at what happened to this thread that
> reported the very same error? I thought this got fixed.
>
> http://sources.redhat.com/ml/gdb-patches/2002-03/msg00533.html

Jason reported the same bug and posted a patch that appears logically 
equivalent to mine.  Andrew approved it.  There was much discussion of 
related things but Jason never committed his patch.

-- 
Martin Hunt
GDB Engineer
Red Hat, Inc.

Re: [RFA] small patch to command_line_handler

[Andrew Cagney]

> On Friday 07 June 2002 02:51 pm, Elena Zannoni wrote:
> 
>> Martin M. Hunt writes:
>>  > Please check this carefully because I don't really understand the code
>>  > here.
>>  >
>>  > I'm trying to track down some memory trashing and random crashes and the
>>  > command line handler is reading memory it didn't allocate, which is
>>  > mostly harmless, but annoying and bad programming.  So here's a proposed
>>  > fix.
>>
>> Hmmm, odd.  Martin, can you look at what happened to this thread that
>> reported the very same error? I thought this got fixed.
>>
>> http://sources.redhat.com/ml/gdb-patches/2002-03/msg00533.html
> 
> 
> Jason reported the same bug and posted a patch that appears logically 
> equivalent to mine.  Andrew approved it.  There was much discussion of 
> related things but Jason never committed his patch.

I'll approve this version then :-)

Andrew