[syslinux] CMENU file handling problems.

[arcarlini at iee.org]

H. Peter Anvin wrote:
> Sounds like some kind of file descriptor leak, indeed.  The
> number 29 is particularly suspicious: 32-3 (for stdin/stdout/stderr).

I added some debug (dumping C if (__file_info[i].iop == 0 &&
__file_info[i].oop == 0), o otherwise).

ifp1 opens a file that exists but doesn't close it.

ifp2 opens a file that does not exist (and would fclose it if it
existed) 24 times.

At this stage there are 28 open files and 4 closed ones.

ifp3 opens and closes a file that exists.

At this stage there are 28 open files and 4 closed ones.

ifp2 opens and closes a file that exists.

At this stage there are 28 open files and 4 closed ones.

(There's no significance to the exists/doesn't exist sequence: that's
just what the program happened to be doing when I added the debug).

So opening a real file and closing works as expected.

fopen on a non-existent file takes up a slot in the __file_info and
fails to release it when it fails.

I tried the sneaky "perhaps I can call fclose even if fopen failed"
gambit, but it didn't go well.

I'll poke a round a bit more in a while.

Thanks

Antonio
arcarlini at iee.org