Re: segfault in strftime

[Peter Stephenson <pws@xxxxxxx>]

On Fri, 26 Feb 2010 14:59:09 +0100
Sebastian Stark <seb-zsh@xxxxxxxxxxx> wrote:
> I'm not used to produce or read backtraces, is the following helpful?

That's very interesting, thank you.

> Does it mean the problem is my libc?

No...

> #1  0x000000000049bb54 in ztrftime (buf=0x6feed0 "\001J!Î+", bufsize=158, fmt=0x2ba7cd751832 " %d.%m.%Y %H:%M:%S", tm=0x0)
                    ^^^^^^
>     at utils.c:2603

This is the interesting bit.  localtime() dectected a value it couldn't
convert to a structure and returned NULL.  It's allowed to do that if it
didn't like the value passed, though I'm not sure why it wouldn't.  It
seems not all time_t's can be converted to times, a fact I was hitherto
unaware of.

Index: Src/Modules/datetime.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/Modules/datetime.c,v
retrieving revision 1.18
diff -p -u -r1.18 datetime.c
--- Src/Modules/datetime.c	9 Dec 2007 14:58:36 -0000	1.18
+++ Src/Modules/datetime.c	26 Feb 2010 14:08:55 -0000
@@ -121,6 +121,10 @@ bin_strftime(char *nam, char **argv, Opt
     }
 
     t = localtime(&secs);
+    if (!t) {
+	zwarnnam(nam, "%s: unable to convert to time", argv[1]);
+	return 1;
+    }
     bufsize = strlen(argv[0]) * 8;
     buffer = zalloc(bufsize);
 

-- 
Peter Stephenson <pws@xxxxxxx>            Software Engineer
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