Messages in this thread | | | Date | Sun, 23 Sep 2007 01:37:44 +0200 | From | David Härdeman <> | Subject | Re: RFC: A revised timerfd API |
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On Sat, Sep 22, 2007 at 06:07:14PM +0200, Michael Kerrisk wrote: >On 9/22/07, Bernd Eckenfels <ecki@lina.inka.de> wrote: >> In article <46F514C9.5010208@gmx.net> you wrote: >> > 1. This design stretches the POSIX timers API in strange >> > ways. >> >> Maybe it is possible to reimplement the POSIX API in usermode using the >> kernel's FD implementation? > >It's a clever idea... Without thinking on it too long, I'm not sure >whether or not there might be some details which would make this >difficult.
It seems to be a dangerous idea. It has the potential of breaking userspace applications that rely on POSIX timers not creating fd's.
Image code like this:
/* Close stdin, stdout, stderr */ close(0); close(1); close(2);
/* Oh, a timer would be nice */ timer_create(x, y, z);
/* Create new stdin, stdout, stderr */ fd = open("/dev/null", flags); dup(fd); dup(fd);
Unless timer_create does some magic to avoid using the lowest available fd, this would suddenly break as the timerfd would be fd 0.
-- David Härdeman - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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