[Cgdb-devel] [patch] -d parameter fix and enhancement

[Horst S. <ho...@sc...>]

Hi,

when using cgdb 0.6.3, I stumbled upon the following problem when
trying to pass additional source paths to gdb by invoking cgdb this way:

$ cgdb -d/tmp dot

This of course does not work, as I learned very soon, due to the fact
that -d is a valid parameter for both cgdb and gdb; this is annoying,
but fixable.

But while trying to figure out what was wrong, I realized that there's a
bug in cgdb regarding the very same parameter:

$ gdb cgdb
GNU gdb 6.5
Copyright (C) 2006 Free Software Foundation, Inc.
[...]
(gdb) run -d/tmp
Starting program: /usr/bin/cgdb -d/tmp
Failed to read a valid object file image from memory.
(no debugging symbols found)
[...]
*** glibc detected *** free(): invalid pointer: 0x08071c80 ***

Program received signal SIGABRT, Aborted.
0xb7eee410 in ?? ()


After some debugging, I figured out the bug sits is in the
parse_long_options() function in cgdb.c: n gets increased by 2 even if
the -d parameter was passed as one argv entry (as in "-dfoo"), although
2 is only correct for separate argv entries (as in "-d foo").

Please consider including my patch (see below) in your cgdb sources; it
addresses the mentioned "-dfoo vs. -d foo" bug, adds a way to cleanly
separate cgdb parameters from gdb parameters, and documents this in the
man page.

After applying it, you can start cgdb this way:

$ cgdb -d/some/specific/gdb -- -d/tmp -d/foo dot

Btw: Thanks for this nice tool :)

Kind regards,
 Horst


 cgdb/src/cgdb.c |   13 ++++++++++++-
 doc/cgdb.1      |    5 ++++-
 2 files changed, 16 insertions(+), 2 deletions(-)

diff -Nurp cgdb-0.6.3-orig/cgdb/src/cgdb.c cgdb-0.6.3/cgdb/src/cgdb.c
--- cgdb-0.6.3-orig/cgdb/src/cgdb.c	2006-06-03 20:09:06.000000000 +0200
+++ cgdb-0.6.3/cgdb/src/cgdb.c	2006-08-02 18:34:35.000000000 +0200
@@ -717,7 +717,13 @@ parse_long_options (int *argc, char ***a
 	  exit (0);
 	case 'd':
 	  debugger_path = strdup (optarg);
-	  n += 2;
+	  if (optarg == (*argv)[n + 1]) {
+	    /* optarg is in next argv (-d foo) */
+	    n += 2;
+	  } else {
+	    /* optarg is in this argv (-dfoo) */
+	    n++;
+	  }
 	  break;
 	case 'h':
 	  usage ();
@@ -729,6 +735,11 @@ parse_long_options (int *argc, char ***a
 
   *argc -= n;
   *argv += n;
+
+  if (strcmp(**argv, "--") == 0) {
+    (*argc)--;
+    (*argv)++;
+  }
 }
 
 /* init_home_dir: Attempts to create a config directory in the user's home
diff -Nurp cgdb-0.6.3-orig/doc/cgdb.1 cgdb-0.6.3/doc/cgdb.1
--- cgdb-0.6.3-orig/doc/cgdb.1	2006-06-03 20:10:47.000000000 +0200
+++ cgdb-0.6.3/doc/cgdb.1	2006-08-02 18:44:50.000000000 +0200
@@ -5,7 +5,7 @@ CGDB \- manual page for CGDB 0.6.3

 .SH DESCRIPTION
 .SS "CGDB Usage:"
 .IP
-cgdb [cgdb options] [gdb options]
+cgdb [cgdb options] [--] [gdb options]
 .SS "CGDB Options:"
 .TP
 \fB\-\-version\fR
@@ -16,6 +16,9 @@ Print help (this message) and then exit.
 .TP
 \fB\-d\fR
 Set debugger to use.
+.TP
+\fB\-\-\fR
+Separator to avoid ambiguities between gdb and cgdb options.
 .PP
 Copyright 2002\-2006 Bob Rossi and Mike Mueller.
 CGDB is free software, covered by the GNU General Public License, and you are


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