Re: [PATCH 0/3] *at syscalls: Intro

From: Nicholas Miell
Date: Thu Dec 15 2005 - 20:13:11 EST


On Thu, 2005-12-15 at 17:49 -0500, Ulrich Drepper wrote:
> Here is a series of patches which introduce in total 11 new system calls
> which take a file descriptor/filename pair instead of a single file name.
> These functions, openat etc, have been discussed on numerous occasions.
> They are needed to implement race-free filesystem traversal, they are
> necessary to implement a virtual per-thread current working directory
> (think multi-threaded backup software), etc.
>

Actually, that last part is false (or maybe just misleading). You can
create threads without CLONE_FS to get a per-thread cwd/chroot/umask, no
"virtual" required.

Don't take this as an objection to implementation of the *at() syscalls
in Linux, though; rather, look at is as a request for the addition of
int pthread_attr_setfssharing_np(pthread_attr_t *attr, int share) and
int pthread_attr_getfssharing_np(pthread_attr_t *attr) to glibc.

--
Nicholas Miell <nmiell@xxxxxxxxxxx>

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