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[RFA2] Follow-up decode_line_1 crash
- To: gdb-patches at sources dot redhat dot com
- Subject: [RFA2] Follow-up decode_line_1 crash
- From: Keith Seitz <keiths at cygnus dot com>
- Date: Wed, 14 Mar 2001 08:23:21 -0800 (PST)
Problem:
$ gdb -nw -nx -q
(gdb) b "foo"
Segmentation fault (core dumped)
decode_linespec_1 does something like:
char *p = *argptr; (the first quote in "foo")
if (p == '"')
{
p++;
is_quote_enclosed = 1;
}
if (is_quote_enclosed)
{
char *closing_quote = strchr (p, '"');
if (closing_quote && closing_quote[1] == '\0')
*closing_quote = '\0';
}
/* so now p looks like foo with no quotes and *argptr is "foo */
char *copy = (char *) alloca (p - *argptr + 1); <-- alloca of 0 bytes
memcpy (copy, *argptr, p - *argptr); <-- copy -1 bytes
Patch:
Index: linespec.c
===================================================================
RCS file: /cvs/cvsfiles/devo/gdb/linespec.c,v
retrieving revision 2.4
diff -p -p -r2.4 linespec.c
*** linespec.c 2000/12/20 14:34:15 2.4
--- linespec.c 2001/03/14 16:16:11
*************** decode_line_1 (char **argptr, int funfir
*** 611,620 ****
s = NULL;
p = *argptr;
! if (p[0] == '"')
{
is_quote_enclosed = 1;
! p++;
}
else
is_quote_enclosed = 0;
--- 611,620 ----
s = NULL;
p = *argptr;
! if (**argptr == '"')
{
is_quote_enclosed = 1;
! (*argptr)++;
}
else
is_quote_enclosed = 0;
Tested on RH6.2. Should be generic enough to apply to all targets. I'm no
expert at this stuff, but a crash is Just Plain Bad (TM).
Keith