Tcl Source Code

Version: TCL 8.4.2

OS: Mac OSX 10.1.5 (or any platform where TCL_THREADS is 
defined)

Behavior: Directory entries are not read correctly when TCL 
commands such as glob are used. Instead the result indicates 
that no entries could be found.

Expected Behavior: glob *.o should return a list of .o files within a 
directory (it there are any of course)

The last argument in the call to memcpy in the function 
TclpReaddir in source file tclUnixThrd.c is incorrect. The sizeof 
operator is applied to the address of the item being copied instead 
of the item itself and consequently only a fraction of the 
necessary directory information is being copied.

8.4.2 code:

        memcpy((VOID *) &tsdPtr->rdbuf.ent, (VOID *) ent,
                sizeof(&tsdPtr->rdbuf));

should read:

        memcpy((VOID *) &tsdPtr->rdbuf.ent, (VOID *) ent,
                sizeof(tsdPtr->rdbuf));

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Closing as Zoran noted it was fixed.

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I can't say for sure, without actually testing this, but I suppose 
yes, it will break. 
So, the better way, as I said is to try the regular bug-report 
path. 
I will try the bugreporter.apple.com. Lets see how this works. 
 
BTW, this one is now fixed both in 8.4 branch and in head. 
Zoran

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so does this mean that the code in tclUnixThrd.c fails on OS X 
even if HAVE_READDIR_R is not defined due to the opendir/
closedir bug?

I have had good experiences with bug reports to
http://bugreporter.apple.com
but I fear it may already be too late now to get a fix into 10.3, 
you should ask if this bug is known and if it will be fixed in 10.3 
on the darwin developers list
http://www.lists.apple.com/mailman/listinfo/darwin-development
many apple engineers working at the libc level hang out there.
Might be useful to mention the realpath issue as well.

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Well, the readdir_r is supposed to be thread-safe, but 
on osx, when many threads are doing: 
 
  opendir 
  readdir_r 
  closedir 
 
in parallel, you get memory corruption in closedir 
after a while.  
What I did was wrap all those with my own wrappers 
with my_opendir doing the actual opendir, slurping 
all dir entries in an linked list with readdir_r and 
my_readdir simply traversing this list. The my_closedir 
frees the whole thing. All work of my_opendir is done 
under mutex protection. This was the only way I could 
solve the memory-trashing, which happens otherwise. 
 
I'm not sure you can plug this into Tcl current layout 
easily. That's why I suggest to wait for Apple to catch 
up and update the OS and correct the bug. 
 
No; I haven't posted a bug to Apple yet. Somehow I have 
a very bad feeling about that (i.e. waste of time) judging 
from my own previous experiences with the company.  
But I may be wrong and things may have changed since... 
 
Zoran

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oy, that's bad, the point of _r in readdir_r is supposed to be that 
it's thread safe... I hope you have reported this as a bug to 
Apple?
Given that I have to do something for realpath in the 
makesystem already, I'll see about removing HAVE_READDIR_R  
as well so that the tcl version gets used.

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Oh yes. The readdir_r in 10.2 (at least the version I have) 
is also broken when multiple threads are engaged in file tree 
walks. The problem is difficult to reproduce (as with all MT 
problems, phew) but it's there.  
We have our own kind of "find" utility employing MT 
and written for the AOLserver. Now, for that, I had to write 
my own readdir/opendir/closedir wrappers. 
I hope to see the problem solved with the new release  
of MacOSX. If not, we must/should do something there 
as well. I wouldn't rush, though, because most of the people 
won't hit this one. 
 
Speaking of 10.1 bug, it is ok. I will correct it in the CVS now. 
Zoran.

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oops, I meant "check this in", not "check this"...

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Zoran,
could you check this soon so that it makes it into 8.4.3 (or I can 
do it if you prefer), 8.4.2 is completely broken on 10.1 due to 
this...

are you saying that we should use the tcl provided version of 
readdir_r  on 10.2 and later as well (similar to what we need to 
do for realpath in bug 711232)?

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 Well, this is happening for older 10.1.xxx OSX since  
newer ones have readdir_r already. 
But the bug report is correct, i.e. there is a  
mistake in the code, as described. I will correct 
this in both CVS HEAD and in 8.4 branch if  
nobody objects. 
 
Th problem is: even the newer readdir_r with its 
opendir/closedir companions is broken for MT. 
 
I will have to avait the new OSX update and if it  
shows same problems, I might talk to Daniel Steffen 
and Jim Ingham how best to correct that. 
 
Zoran

File Added - 48090: tclUnixThrd.c