[RFA] Fix memory corruption bug in mdebugread.c

[Fred Fish <fnf at fred dot ninemoons dot com>]

The code to handle stabs continuation in mdebugread.c incorrectly
attempts to overwrite memory returned by realloc with the original
contents of the memory passed to realloc.  This is wrong for two
reasons; first realloc will do any copying needed if the string is
moved, and second, the copy at the old location may be corrupted by
the time realloc returns a pointer to the new location.

This patch fixes the problem.

-Fred

2002-01-23  Fred Fish  <fnf@redhat.com>

	* mdebugread.c (parse_partial_symbols): Only copy stabstring1 to
	stabstring on initial malloc.  Reallocing will copy it for us,
	if necessary.

Index: mdebugread.c
===================================================================
RCS file: /cvs/src/src/gdb/mdebugread.c,v
retrieving revision 1.22
diff -c -p -r1.22 mdebugread.c
*** mdebugread.c	2002/01/20 19:42:04	1.22
--- mdebugread.c	2002/01/24 00:02:24
*************** parse_partial_symbols (struct objfile *o
*** 2707,2714 ****
  		     && stabstring != debug_info->ss + fh->issBase + sh.iss)
  		      stabstring = xrealloc (stabstring, len + len2 + 1);
  		    else
! 		      stabstring = xmalloc (len + len2 + 1);
! 		    strcpy (stabstring, stabstring1);
  		    strcpy (stabstring + len, stabstring2);
  		    len += len2;
  		  }
--- 2707,2716 ----
  		     && stabstring != debug_info->ss + fh->issBase + sh.iss)
  		      stabstring = xrealloc (stabstring, len + len2 + 1);
  		    else
! 		      {
! 			stabstring = xmalloc (len + len2 + 1);
! 			strcpy (stabstring, stabstring1);
! 		      }
  		    strcpy (stabstring + len, stabstring2);
  		    len += len2;
  		  }