[issue992] telldir/seekdir broken [PATCH]

[Gary Stanley]

New submission from Gary Stanley <gary at velocity-servers.net>:

FreeBSD has a bug in telldir that returns incorrect results, causing memory 
leaks and other odd behavior. This bug was fixed in NetBSD, and I've created a 
patch based on NetBSD's changes. This will also add a pointer to dd_internal 
in dirent.h, which will probably require a version bump because the size of 
that struct will change. I didn't bother bumping version here because it seems 
it didn't effect anything (ls, du, etc), but its better to be safe than sorry.

The code to generate the issue is here:

http://leaf.dragonflybsd.org/~gary/patches/libc/seekdir-twice.c

Fixed telldir:

first found: a
pos returned by telldir: 135286864
second found: b
third found: c
should be == second: b
pos given to seekdir: 135286864
pos returned by telldir: 135286864
should be == second: b
should be == second: b

Broken telldir:

first found: a
pos returned by telldir: 1
second found: b
third found: c
should be == second: b
pos given to seekdir: 1
pos returned by telldir: 2
should be == second: c
should be == second: c

The patch is located here: 
http://leaf.dragonflybsd.org/~gary/patches/libc/libc-telldir-memleaks.patch

Some notes:
telldir's behavior now follows opengroup's behavior, that it isn't const, 
which it seems is more of a standards issue than anything.
 
http://www.opengroup.org/onlinepubs/009695399/functions/telldir.html

tgen@ has looked over the patch and says its good, only concern was the 
unconst change to telldir, which I explained to him above :)

----------
messages: 4501
nosy: gstanley
priority: bug
status: unread
title: telldir/seekdir broken [PATCH]

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