A while back, I volunteered to maintain x11-wm/piewm, as it had been assigned to "ports" and I'm one of the very few folks I know who uses it.
The vast bulk of this code dates back to tvtwm and twm before that;
the primary source file is still called "twm.c" and had last been
updated 12 June 1998.
While I have been generally using piewm successfully (modulo a
couple of fixes I sent upstream a few years back) in a FreeBSD/i386
environment, I recently decided to experiment with FreeBSD/amd64
on my laptop.
While the experiment worked OK for the most part, I was not at all
happy to find that piewm survived but briefly on invocation in an
amd64 environment. Further, I found that tvtwm (my fallback WM)
did not exhibit such a failure. (This is not the first time such
a difference in behavior has been observed.)
After poking around (more like "thrashing") for a bit, I managed
-- somehow -- to determine that piewm was getting a SIGSEGV very
early on, when it attempted to access the execution "environment."
(It turns out that tvtwm doesn't do this. There is virtue in
simplicity. :-})
I was puzzled by this, as it does the same thing for i386, and didn't
choke & die.
So I started looking at code that I had reason to expect would do this
correctly -- src/usr.bin/env/env.c, for starters -- and saw that while
piewm's twm.c declares main as:
int
main(int argc, char **argv, char **environ)
{
...
and proceeds to use environ as a pointer to a NULL-terminated list
of strings, env.c declares:
extern char **environ;
and the function main is declared:
int
main(int argc, char **argv)
{
...
And that difference struck me as possibly of significance.
So I hacked twm.c, per:
--- twm.c 1998-06-12 13:28:07.000000000 -0700
+++ twm.c 2013-05-10 21:02:32.000000000 -0700
@@ -93,6 +93,7 @@
#endif
#include <stdio.h>
+#include <stdlib.h>
#include <signal.h>
#include <fcntl.h>
#include "twm.h"
@@ -177,6 +178,8 @@
unsigned long black, white;
+extern char **environ;
+
/***********************************************************************
*
* Procedure:
@@ -186,7 +189,7 @@
*/
int
-main(int argc, char **argv, char **environ)
+main(int argc, char **argv)
{
Window root, parent, *children;
unsigned int nchildren;
rebuilt piewm, et voilà: no crash. :-)
I thought this was encouraging, and sent a note to Russ Nelson at
crynwr.com -- the upstream site. That was on 10 May; I've had no
response.
I subsequently rebuild piewm with the patch applied for my usual
FreeBSD/i386 environment, and it's (also) been trouble-free. (That
said, I don't actually do anything with the environment for piewm.
Indeed, in nearly all respects, I could use tvtwm without any difference
-- and those that would show up are too arcane to describe here.)
So I have a couple of questions related to the above:
* Is the patch correct? I don't do much with C, and even less with C
code that accesses the environment. (When I write code, it's normally
scripts, mostly in /bin/sh.) getenv(3) mentioned the "#include
<stdlib.h>", so I did that based on theat man page. I didn't see
anything about declaring environ as an "extern char **", but wasn't
keen on making more changes than necessary to the code. (Mind, I
fully support making "necessary" -- or even "strongly advised" --
changes.)
* I also prefer getting the changes pushed upstream -- I believe I was
reponsible for the previous couple of changes to piewm, because of bugs
I found. But so far, "upstream" hasn't responded, and the code (as it
presently stands) is demonstrably broken for amd64.
All that said, it's fair to note that (at best), piewm is a
vanishingly small niche. However, other than tvtwm, I haven't
found a WM with which I am anywhere near as comfortable; thus, I
have a rather vested interest in ensuring that it continues to
work.
But if Russ Nelson is no longer in a position to be both willing &
able to host the upstream site, I'm willing to do it myself.
What's a reasonable way for me to proceed?
(I'm subscribed to ports@; no need to Cc: me.)
Thanks!
Peace,
david
--
David H. Wolfskill da...@catwhisker.org
Taliban: Evil men with guns afraid of truth from a 14-year old girl.
See http://www.catwhisker.org/~david/publickey.gpg for my public key.
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