This macro will read a pointer of any type, return it, and set the
pointer to NULL. This is useful as an explicit concept of passing
ownership of a memory area between pointers.
This takes inspiration from Rust:
https://doc.rust-lang.org/std/option/enum.Option.html#method.take
and was suggested by Alan Jenkins (@sourcejedi).
It drops ~160 lines of code from our codebase, which makes me like it.
Also, I think it clarifies passing of ownership, and thus helps
readability a bit (at least for the initiated who know the new macro)
Even if pager_open() fails, in general, we should continue the operations.
All erroneous cases in pager_open() show log message in the function.
So, it is not necessary to check the returned value.
The kernel needs two numbers, but for the user it's most convenient to provide the
user name and have that resolved to uid and gid.
Right now the primary group of the specified user is always used. That's the most
common case anyway. In the future we can extend the --owner option to allow a group
after a colon.
[I added this before realizing that this will not be enough to be used for user
runtime directory. But this seems useful on its own, so I'm keeping this commit.]
If the specified direcotry does not exist, then systemd creates it
when the mount unit starts. So, it is not necessary to check the
existence in the client tool.
The command `systemd-mount -u` tries to stop both mount and automount
units. If the corresponding mount unit does not exist, then it is
user's fault, that is, the specified path is not a mount point.
However, not all mount units have corresponding autmount units.
Thus, the error about non-existing automount unit is not user's falut,
and showing the error may confuse users.
So, let's ignore the error of such case.
Already, path_is_safe() refused paths container the "." dir. Doing that
isn't strictly necessary to be "safe" by most definitions of the word.
But it is necessary in order to consider a path "normalized". Hence,
"path_is_safe()" is slightly misleading a name, but
"path_is_normalize()" is more descriptive, hence let's rename things
accordingly.
No functional changes.
ENOENT is a bit too likely to be returned for various reasons, for
example if /sys or /proc are not mounted and hence the files we need not
around. Hence, let's use ENXIO instead, which is equally fitting for the
purpose but has the benefit that the underlying calls won't generate
this error on their own, hence any ambiguity is removed.
We should either log about all errors in a function, or about none (and
then leave the logging about it to the caller who we propagate the error
to). Given that the callers of find_loop_device() already log about the
returned errors let's hence suppress the log messages in
find_loop_device() itself.
It's unlikely this can ever be triggered, but let's be safe rather than
sorry, and handle the case where the list of mount points is zero, and
the "l" array thus NULL. let's ensure we allocate at least one entry.
This makes `systemd-umount` or `systemd-mount -u` support unmounting
loop devices by the corresponding backing files, like
`systemd-mount --umount /tmp/foo.img /tmp/bar.img`
Fixes#6206.
This makes systemd-umount (or systemd-mount -u) supports multiple arguments
which can be path, device, or fstab style node name, like
`systemd-umount /path/to/umount /dev/sda1 UUID=xxxxxx-xxxx LABEL=xxxxx`.
C.f. https://github.com/systemd/systemd/pull/5235#issuecomment-277731314.
systemd-mount --unmount /some/path
systemd-mount --umount /some/path
systemd-mount -u /some/path
systemd-unmount /some/path
all do the same thing that one could expect from the name.
to prevent:
src/mount/mount-tool.c: In function ‘acquire_description’:
src/mount/mount-tool.c:728:24: warning: return makes integer from pointer without a cast [-Wint-conversion]
return NULL;
^~~~
warning.
Additionally we don't set Description property in a case when
arg_description is NULL.
This adds "systemd-mount" which is for transient mount and automount units what
"systemd-run" is for transient service, scope and timer units.
The tool allows establishing mounts and automounts during runtime. It is very
similar to the usual /bin/mount commands, but can pull in additional
dependenices on access (for example, it pulls in fsck automatically), an take
benefit of the automount logic.
This tool is particularly useful for mount removable file systems (such as USB
sticks), as the automount logic (together with automatic unmount-on-idle), as
well as automatic fsck on first access ensure that the removable file system
has a high chance to remain in a fully clean state even when it is unplugged
abruptly, and returns to a clean state on the next re-plug.
This is a follow-up for #2471, as it adds a simple client-side for the
transient automount logic added in that PR.
In later work it might make sense to invoke this tool automatically from udev
rules in order to implement a simpler and safer version of removable media
management á la udisks.
Lennart Poettering