Systemd/src/nspawn/nspawn-def.h

/* SPDX-License-Identifier: LGPL-2.1+ */
#pragma once

#include <sys/types.h>

/* While we are chmod()ing a directory tree, we set the top-level UID base to this "busy" base, so that we can always
 * recognize trees we are were chmod()ing recursively and got interrupted in */
#define UID_BUSY_BASE ((uid_t) UINT32_C(0xFFFE0000))
#define UID_BUSY_MASK ((uid_t) UINT32_C(0xFFFF0000))
nspawn: add missing spdx header 2020-07-22 17:50:45 +02:00			`/* SPDX-License-Identifier: LGPL-2.1+ */`
nspawn: make recursive chown()ing logic safe for being aborted in the middle We currently use the ownership of the top-level directory as a hint whether we need to descent into the whole tree to chown() it recursively or not. This is problematic with the previous chown()ing algorithm, as when descending into the tree we'd first chown() and then descend further down, which meant that the top-level directory would be chowned first, and an aborted recursive chowning would appear on the next invocation as successful, even though it was not. Let's reshuffle things a bit, to make the re-chown()ing safe regarding interruptions: a) We chown() the dir we are looking at last, and descent into all its children first. That way we know that if the top-level dir is properly owned everything inside of it is properly owned too. b) Before starting a chown()ing operation, we mark the top-level directory as owned by a special "busy" UID range, which we can use to recognize whether a tree was fully chowned: if it is marked as busy, it's definitely not fully chowned, as the busy ownership will only be fixed as final step of the chowning. Fixes: #6292 2017-11-16 19:09:32 +01:00			`#pragma once`

			`#include <sys/types.h>`

			`/* While we are chmod()ing a directory tree, we set the top-level UID base to this "busy" base, so that we can always`
			`* recognize trees we are were chmod()ing recursively and got interrupted in */`
			`#define UID_BUSY_BASE ((uid_t) UINT32_C(0xFFFE0000))`
			`#define UID_BUSY_MASK ((uid_t) UINT32_C(0xFFFF0000))`