File descriptor leak in nftw(FTW_CHDIR) ?

Question

I am using the POSIX call nftw() for traversing a directory structure. The directory structure is flat - only 4 files and no subdirectories.

However when I call nftw() a lot of times on this flat directory then I get an error message after a while:

"too many open file handles".

It turned out that this happens when the flag FTW_CHDIR is used.

Would you agree that it is a bug in the Linux implementation of nftw() ?

UPDATE

A fix is now available in the glibc repositories.

here are some links to the source code I have used for testing:

• main.cpp: http://sourceware.org/bugzilla/attachment.cgi?id=4586&action=view
• Makefile: http://sourceware.org/bugzilla/attachment.cgi?id=4587&action=view

UPDATE

• MacOS-X is also hit by the bug
• Solaris9, Solaris10 and AIX 5.3 do not have the bug

Answer 1

For me it looks like there is really something wrong with the nftw implementation on linux.

I have filed a bug report, see here

UPDATE: A fix is available in the glibc repositories now.

Answer 2

It has the same behaviour on Mac OS 10.6.2. So probably somehow part of the specification, though I don't see how exactly.

Answer 3

Regarding Mac OS: bugreport submitted to Apple as radar #7640283. (No hyperlink possible, unfortunately.)