When switching to another user it's oftentimes desirable to also spawn
the target user's shell. sudo supports this via -i flag, run0 currently
doesn't. We don't want to proactively query NSS ourselves, since
that would fall short when operating remotely. Let's instead teach
the service manager to spawn the command using the user's default shell.
I opted for "|" instead of "." in the end because the latter seems
a bit obscure. But happy to change it to something else if a better option
comes up.
Otherwise, initrd-cleanup.service requests isolation thus the socket
is stopped before switching root, and several early events after
switching root may be lost.
As a test, it just increases our code coverage in a fake way.
When run manually, it can be used to conveniently print what logind
thinks about various processes:
$ build/test-sd-login
sd_pid_get_session(0) → No data available
sd_pid_get_unit(0) → user@1000.service
sd_pid_get_user_unit(0) → app-ghostty-transient-5088.scope
sd_pid_get_machine_name(0) → No such file or directory
sd_pid_get_slice(0) → user-1000.slice
sd_pid_get_user_slice(0) → app.slice
sd_pid_get_owner_uid(0) → 1000
sd_pid_get_cgroup(0) → /user.slice/user-1000.slice/user@1000.service/app.slice/app-ghostty-transient-5088.scope/surfaces/556FAF50BA40.scope
$ build/test-sd-login cgroup 1
sd_pid_get_cgroup(1) → /init.scope
The existing text grew organically as features were added and was
not very organized. Reorder it and break into paragraphs grouped
by topic. The description of the :errno syntax is replaced by a short
reference to the SystemCallErrorNumber= setting. This makes the
text shorter and makes it easier to explain how the two settings combine.
Passing in the func, file and line information complicates the
interface. On top of that, it prevents forward declaring Hashmap in
strv.h, as we need to pass the macros everywhere that we allocate a
hashmap, which means we have to include the hashmap header everywhere
we have a function that allocates a hashmap instead of just having to
forward declare Hashmap.
Let's drop the file, func and line information from the debug information.
Instead, in the future we can add a description field to hashmaps like we
already have in various other structs to describe the purpose of the hashmap
which should be much more useful than having the file, line and function where
the hashmap was allocated.
abs() requires including the entirety of stdlib.h just for a single
trivial function. Let's introduce the ABS() macro and use it in header
files instead so we can get rid of stdlib.h transitive includes in header
files in a later commit.
Let's move some more implementation logic into functions. We keep
the logic that requires the macro in the macro and move the rest into
functions.
While we're at it, let's also make the parameter declarations of
all the string table macros less clausthrophobic.
Mike Yuan
Yu Watanabe
Daan De Meyer
Zbigniew Jędrzejewski-Szmek
damnkiwi6120
Salim B
Lennart Poettering
Jelle van der Waa