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8 commits

Author SHA1 Message Date
Lennart Poettering e49ee28522 mount-util: add destructor helper that umounts + rmdirs a path 2020-07-07 11:20:42 +02:00
Lennart Poettering 6b000af4f2 tree-wide: avoid some loaded terms
https://tools.ietf.org/html/draft-knodel-terminology-02
https://lwn.net/Articles/823224/

This gets rid of most but not occasions of these loaded terms:

1. scsi_id and friends are something that is supposed to be removed from
   our tree (see #7594)

2. The test suite defines an API used by the ubuntu CI. We can remove
   this too later, but this needs to be done in sync with the ubuntu CI.

3. In some cases the terms are part of APIs we call or where we expose
   concepts the kernel names the way it names them. (In particular all
   remaining uses of the word "slave" in our codebase are like this,
   it's used by the POSIX PTY layer, by the network subsystem, the mount
   API and the block device subsystem). Getting rid of the term in these
   contexts would mean doing some major fixes of the kernel ABI first.

Regarding the replacements: when whitelist/blacklist is used as noun we
replace with with allow list/deny list, and when used as verb with
allow-list/deny-list.
2020-06-25 09:00:19 +02:00
Topi Miettinen b4e1563ffb Increase size of /run to 20%
For low memory machines (256MB), 10% of RAM for /run may not be enough for
re-exec of PID1 because 16MB of free space is required and /run may already
contain something.
2020-05-15 21:40:22 +02:00
Topi Miettinen 7d85383edb tree-wide: add size limits for tmpfs mounts
Limit size of various tmpfs mounts to 10% of RAM, except volatile root and /var
to 25%. Another exception is made for /dev (also /devs for PrivateDevices) and
/sys/fs/cgroup since no (or very few) regular files are expected to be used.

In addition, since directories, symbolic links, device specials and xattrs are
not counted towards the size= limit, number of inodes is also limited
correspondingly: 4MB size translates to 1k of inodes (assuming 4k each), 10% of
RAM (using 16GB of RAM as baseline) translates to 400k and 25% to 1M inodes.

Because nr_inodes option can't use ratios like size option, there's an
unfortunate side effect that with small memory systems the limit may be on the
too large side. Also, on an extremely small device with only 256MB of RAM, 10%
of RAM for /run may not be enough for re-exec of PID1 because 16MB of free
space is required.
2020-05-13 00:37:18 +02:00
Lennart Poettering 7cce68e1e0 core: make sure we use the correct mount flag when re-mounting bind mounts
When in a userns environment we cannot take away per-mount point flags
set on a mount point that was passed to us. Hence we need to be careful
to always check the actual mount flags in place and manipulate only
those flags of them that we actually want to change and not reset more
as side-effect.

We mostly got this right already in
bind_remount_recursive_with_mountinfo(), but didn't in the simpler
bind_remount_one_with_mountinfo(). Catch up.

(The old code assumed that the MountEntry.flags field contained the
right flag settings, but it actually doesn't for new mounts we just
established as for those mount() establishes the initial flags for us,
and we have to read them back to figure out which ones the kernel
picked.)

Fixes: #13622
2020-01-09 15:18:08 +01:00
Anita Zhang e5f10cafe0 core: create inaccessible nodes for users when making runtime dirs
To support ProtectHome=y in a user namespace (which mounts the inaccessible
nodes), the nodes need to be accessible by the user. Create these paths and
devices in the user runtime directory so they can be used later if needed.
2019-12-18 11:09:30 -08:00
Lennart Poettering 64e82c1976 mount-util: beef up bind_remount_recursive() to be able to toggle more than MS_RDONLY
The function is otherwise generic enough to toggle other bind mount
flags beyond MS_RDONLY (for example: MS_NOSUID or MS_NODEV), hence let's
beef it up slightly to support that too.
2019-03-25 19:33:55 +01:00
Zbigniew Jędrzejewski-Szmek 77c772f227 Move mount-util.c to shared/
libmount dep is moved from libbasic to libshared, potentially removing
libmount from some build products.
2018-11-29 21:03:44 +01:00
Renamed from src/basic/mount-util.h (Browse further)