Date: Fri, 23 Jun 1995 22:23:44 -0700 From: Matt Dillon <dillon@best.com> To: Bruce Evans <bde@zeta.org.au> Cc: bugs@FreeBSD.org Subject: Re: connect() bug found and fixed (uninitialized pointer) Message-ID: <199506240523.WAA26119@shell1.best.com>
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:> couple of other programs. As best as I can tell,
:> something gets confused and the parameter offsets
:> get skewed, causing corruption when a bad pointer
:> (due to the skew) is dereferenced.
:
:Runtime problems are most likely caused by %d or %ld format specifiers
:mismatched with quad_t arguments, e.g., off_t's. quad_t's should be
:printed in format %qd. Casts shouldn't normally be used except for
:pointers. Pointer types should be cast to (void *) and printed in
:format %p. -Wall finds most mismatches to give you some chance of
:detecting int vs. long mismatches but it is sloppy about pointers.
:
:Bruce
Yes, I finally figured that out. I think there is a serious problem
though, because MOST third party programs do not put -Wall in
their Makefile, and without -Wall you get not a single warning
about possible quad_t conflicts... everything appears to compile
and link just fine, except the resulting binary does weird things.
Now, for us... obviously we will be putting -Wall in everything we
compile from now on, but I think you will find a lot of people having
serious problems with this quad_t change... rightly, new procedure
names should have been chosen for the relatively few system calls
that need quad_t's (lseek, ftruncate could become lqseek, fqtruncate).
You may wish to consider turning -Wall or, at least, the warning
regarding unprototyped procedure calls, ON by default in gcc. Personally,
I think keeping the same naming conventions was ill-considered.
-Matt
Matthew Dillon VP Engineering, BEST Internet Communications, Inc.
<dillon@best.com>, <dillon@apollo.west.oic.com>
[always include a portion of the original email in any response!]
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