[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Bug#409517: dvipdfm segfault related to /etc/localtime

I've tried Martin's /etc/localtime with his malaga.dvi file on my system and had no problems. The localtime file doesn't appear to be corrupt and this isn't one of those half-hour timezones. I think those are red herrings. This is probably a new problem that might be unique to the AMD64 architecture.
There aren't very many ways I can imagine where the patch would corrupt memory. Possibilities are the call to time() itself, the call to localtime(), and the call to sprintf() which writes to the variable named 'date_string'. In the unpatched code, the buffer named 'date_string' was being overrun due to the half-hour time zones. Assuming the AMD64 time() and localtime() calls work as expected, it's possible the 'date_string' buffer may still be overrun somehow. Since I don't have AMD64/Debian, could you, Martin, run a debugger to see what's being written to 'date_string' in the sprintf() call in pdfdoc.c? If not, could you see if enlarging the date_string buffer has any effect on the problem? 

Mark

On Mon, 5 Feb 2007, Frank Küster wrote:


Date: Mon, 05 Feb 2007 10:18:18 +0100
From: "Frank [iso-8859-1] Küster" <frank@kuesterei.ch>
To: Mark A. Wicks <mwicks@kettering.edu>
Cc: 409517@bugs.debian.org, Martin Michlmayr <tbm@cyrius.com>
Subject: Re: Bug#409517: dvipdfm segfault related to /etc/localtime

Hi Mark,

there seems to be a problem with the timezone patch that we applied
recently to our version of dvipdfm: It again segfaults with certain
timezone files.  I'm not even sure whether /etc/localtime might not be
corrupted - but still it should give an error and not segfault.  On the
other hand, dvipdfm doesn't open localtime, but query it through defined
APIs, well.

Martin Michlmayr <tbm@cyrius.com> wrote:


* Frank Küster <frank@kuesterei.ch> [2007-02-03 21:13]:

Sorry, I have no idea.  But I asked because one of the last changes to
dvipdfm was a patch to *prevent* a segfault when used in a timezone with
half-hour offset from UTC.  It's in the same source file, but at a
different place than indicated by the trace, and I don't see the
relation ATM.  You can look at it at


Reverting this patch (debian/patches/patch-dvipdfm-timezone-crash)
gets rid of my segfault.


So the exact patch that we applied is at

http://svn.debian.org/wsvn/debian-tex/tetex-bin/trunk/debian/patches/patch-dvipdfm-timezone-crash?op=file&rev=0&sc=0

and Martin's complete bug report is at

http://bugs.debian.org/409517

Martin, do you happen to know how tzconfig handles /etc/localtime?  On
my sarge system, /etc/localtime is a symlink to a particular file below
/usr/share/zoneinfo/ (to Europe/Zurich), on my sid system it's an
ordinary file.

Is there an easy way to find out which of the preprocessor conditional
branches we're in?  I'm speaking of

+#ifdef HAVE_TM_GMTOFF  /* Preferred way to get time zone offset */
+  tz_offset = bd_time->tm_gmtoff;
+#else
+#ifdef HAVE_TIMEZONE   /* Plan B --- use external variable 'timezone'
+                       /* (may not provide correct offset for daylight savings time) */
+  tz_offset = - timezone;
+#else                  /* Last resort --- without more information, set offset to zero */
+  tz_offset = 0l;
+#endif /* HAVE_TIMEZONE */
+#endif /* HAVE_TM_GMTOFF */

The file is compiled with this command:

cc -DHAVE_CONFIG_H  -I. -I. -I.. -I./..   -O2 -c pdfdoc.c -o pdfdoc.o

TIA, Frank

--
Dr. Frank Küster
Single Molecule Spectroscopy, Protein Folding @ Inst. f. Biochemie, Univ. Zürich
Debian Developer (teTeX/TeXLive)
Reply to: