Messages in this thread | | | Subject | Re: [PATCH 1/2] fs: introduce sendfd() syscall | From | Eric Dumazet <> | Date | Tue, 02 Dec 2014 04:50:07 -0800 |
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On Tue, 2014-12-02 at 15:35 +1100, Alex Dubov wrote: > Present patch introduces exceptionally easy to use, low latency and low > overhead mechanism for transferring file descriptors between cooperating > processes: > > int sendfd(pid_t pid, int sig, int fd) > > Given a target process pid, the sendfd() syscall will create a duplicate > file descriptor in a target task's (referred by pid) file table pointing to > the file references by descriptor fd. Then, it will attempt to notify the > target task by issuing a Posix.1b real-time signal (sig), carrying the new > file descriptor as integer payload. If real-time signal can not be enqueued > at the destination signal queue, the newly created file descriptor will be > promptly closed. > > Signed-off-by: Alex Dubov <oakad@yahoo.com> > ---
User A can send fd(s) to processes belonging to user B, even if user B does (probably) not want this to happen ?
Also, relying on signals seems quite old fashion these days. How about multi-threaded programs wanting separate channels to receive fds ?
Ability to flood fds and fill target file descriptors table looks very dangerous to me. Some programs could break as they expect they control fd allocations.
I like the idea of not having to use AF_UNIX and stick to a well defined interface, but I do not like this asynchronous model.
Thanks.
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