Re: [RFC/PATCH] revokeat/frevoke system calls V5

From: Kyle Moffett
Date: Mon Feb 26 2007 - 16:36:49 EST


On Feb 26, 2007, at 13:46:21, H. Peter Anvin wrote:
Alan wrote:
I'm not sure. Turning, for example, the statat(dir_fd, name == NULL) error case into fstat(dir_fd) sounds like a way for apps, admittedly buggy ones, to be surprised. Maybe libc would be exptected to catch the error before performing the shared system call?
At that point would it not be cheaper to have two system calls, the table cost isn't very large.

It's not just the table, though, you need two entry points, but even that isn't really all that big either, I guess.

Well, I suppose there are multiple possibilities for consolidation:
frevokeat(fd, "/foo/bar/baz") => normal frevokeat
frevokeat(-1, "/foo/bar/baz") => revoke("/foo/bar/baz");
frevokeat(fd, NULL) => frevoke(fd);

Neither of those would ordinarily be considered to do anything useful and for new syscalls I can't see the possibility of breaking existing programs. On the other hand, it's not like we have any problems with the syscall tables getting too large.

Cheers,
Kyle Moffett

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