The loop preparation and part of the loop contents are actually the
same, let's merge this.
Also, it's so much fun tweaking around in the name_to_handle_at() code,
let's do more of it with this patch!
(This also adds two NULL assignments, that aren't strictly necessary.
However, I figured its safer to place them in there, just in case the
for() condition is changed later. After all the freeing of the handle
and the invalidation of the cleanup-controller pointer to it are
otherwise really far away from each other...)
In -U mode we might need to re-chown() all files and directories to
match the UID shift we want for the image. That's problematic on fat
partitions, such as the ESP (and which is generated by mkosi's
--bootable switch), because fat of course knows no UID/GID file
ownership natively.
With this change we take benefit of the uid= and gid= mount options FAT
knows: instead of chown()ing all files and directories we can just
specify the right UID/GID to use at mount time.
This beefs up the image dissection logic in two ways:
1. First of all support for mounting relevant file systems with
uid=/gid= is added: when a UID is specified during mount it is used for
all applicable file systems.
2. Secondly, two new mount flags are added:
DISSECT_IMAGE_MOUNT_ROOT_ONLY and DISSECT_IMAGE_MOUNT_NON_ROOT_ONLY.
If one is specified the mount routine will either only mount the root
partition of an image, or all partitions except the root partition.
This is used by nspawn: first the root partition is mounted, so that
we can determine the UID shift in use so far, based on ownership of
the image's root directory. Then, we mount the remaining partitions
in a second go, this time with the right UID/GID information.
This adds a new flavour of strextend(), called
strextend_with_separator(), which takes an optional separator string. If
specified, the separator is inserted between each appended string, as
well as before the first one, but only if the original string was
non-empty.
This new call is particularly useful when appending new options to mount
option strings and suchlike, which need to be comma-separated, and
initially start out from an empty string.
Let's optimize things a bit, and instead of having to strip whitespace
first before decoding base64, let's do that implicitly while doing so.
Given that base64 was designed the way it was designed specifically to
be tolerant to whitespace changes, it's a good idea to do this
automatically and implicitly.
If we'd use the system header's version of MAX_HANDLE_SZ then our code
would break on older kernels as soon as the value is increased, as old
kernels refuse larger buffers with EINVAL.
Apparently, the kernel returns EINVAL on NFS4 sometimes, even if we do
everything right, let's fallback in that case and find a different
approach to determine if something's a mount point.
See discussion at:
https://github.com/systemd/systemd/issues/7082#issuecomment-348001289
Now the function returns an empty string when given an empty string.
Not sure if this is the best option (maybe this should be an error?),
but at least the behaviour is well defined.
Also do not include libcryptsetup.h directly, but only through crypt-util.h.
This way we do not have to repeat the define in every file where it is used.
The kernel will reply with -ENOTDIR when we try to access a non-directory under
a name which ends with a slash. But our functions would strip the trailing slash
under various circumstances. Keep the trailing slash, so that
path_is_mount_point("/path/to/file/") return -ENOTDIR when /path/to/file/ is a file.
Tests are added for this change in behaviour.
Also, when called with a trailing slash, path_is_mount_point() would get
"" from basename(), and call name_to_handle_at(3, "", ...), and always
return -ENOENT. Now it'll return -ENOTDIR if the mount point is a file, and
true if it is a directory and a mount point.
v2:
- use strip_trailing_chars()
v3:
- instead of stripping trailing chars(), do the opposite — preserve them.
We never use these functions seperately, hence don't bother splitting
them into to.
Also, simplify things a bit, and maintain tables for the attribute files
to chown. Let's also update those tables a bit, and include thenew
"cgroup.threads" file in it, that needs to be delegated too, according
to the documentation.
Lennart Poettering
Zbigniew Jędrzejewski-Szmek
Yu Watanabe
Vito Caputo
Evgeny Vereshchagin
Daniel Lockyer
Shawn Landden