Messages in this thread | | | From | "Miquel van Smoorenburg" <> | Subject | Re: Suggestion for a new system call: convert file handle to a cookie for transfering file handles between processes. | Date | Sat, 19 Jul 2003 09:59:26 +0000 (UTC) |
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In article <fb7ddfab3b.fab3bfb7dd@teleline.es>, RAMON_GARCIA_F <RAMON_GARCIA_F@terra.es> wrote: >I suggest to add a new system call for transfering a file handle between >two processes. > >In Linux, transfer of file handles can be done through a Unix domain >socket. This mechanism is quite unflexible. It requires that the two >applications connect by this kind of socket, and it is difficult to >use from shell scripts.
Why, write a small program 'passfd /var/run/socket fd1 fd2' which does the work for you.
>Let cdwritter be a program for writting CDs. Unlike other programs, >cdwritter is rationally designed. It is a server process that listens >through a named pipe, thus making it easy to write either command line >or graphical interfaces that use its functionality. The named pipe >is called /var/run/cdwritter > >An alternative would be that cdwritter accepts a file name instead of >a cookie. But then, the author of cdwritter would have to check if the >user has permission to access the file. This makes cdwritter more error >prone.
You can get the uid/gid on the other side of a unix socket easily, so you just setfsuid() / open(). But again you do need to use a Unix socket, not a pipe, so you need a small client program.
There have been patches to the kernel to treat an open() on a unix socket as a bind() + connect(), but unfortunately that has never been integrated in mainline.
Now that we have getsockopt(SO_PEERCRED, &ucred) the above would be very useful.
Mike.
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