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.
So, it appears name_to_handle_at() always returns the right buffer size
on EOVERFLOW, when it's returned due to a too small buffer. Let's rely
on that exclusively for sizing the buffer, and let's drop the
exponential buffer growing.
The new logic is now: if we see EOVERFLOW and the returned size has
increased, resize our buffer and try again. But if it didn't increase,
then propagate the EOVERFLOW as it likely has other causes.
Similar to the virtual ethernet driver veth, vxcan implements a
local CAN traffic tunnel between two virtual CAN network devices.
When creating a vxcan, two vxcan devices are created as pair
When one end receives the packet it appears on its pair and vice
versa. The vxcan can be used for cross namespace communication.
When a process becomes a zombie its cgroup might be deleted. Let's add
some minimal code to detect cases like this, so that we can still
attribute this back to the original cgroup.
