Re: sys_chroot+sys_fchdir Fix

From: Bill Davidsen
Date: Thu Sep 20 2007 - 16:51:12 EST


David Newall wrote:
Philipp Marek wrote:
AFAIK pivot_root() changes the / mapping for *all* processes, no?

The manual page is confusing. It even admits to being "intentionally vague". However the goal seems clear:

"pivot_root() moves the root file system of the current process to
the directory put_old and makes new_root the new root file system of
the current process"
-- man 2 pivot_root

There's an argument that pivot_root could be improved...

And very little argument that the man page could be improved, perhaps. However, there is no question that pivot_root is intended to have breadth for more than one process.

Keeping this functionality sounds a little like putting a bow tie and tux on your bug and calling it a "feature." Not all bugs are useless for legitimate purposes, but it doesn't make them safe. It appears to be a sort-of way to get per-process bind mounts.

--
bill davidsen <davidsen@xxxxxxx>
CTO TMR Associates, Inc
Doing interesting things with small computers since 1979

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