Previously, we discarded any kmsg messages coming from journald
itself to avoid infinite loops where potentially the processing
of a kmsg message causes journald to log one or more messages to
kmsg which then get read again by the kmsg handler, ...
However, if we completely disable logging whenever we're processing
a kmsg message coming from journald itself, we also prevent any
infinite loops as we can be sure that journald won't accidentally
generate logging messages while processing a kmsg log message.
This change allows us to store all journald logs generated during
the processing of log messages from other services in the system
journal. Previously these could only be found in kmsg which has
low retention, can't be queried using journalctl and whose logs
don't survive reboots.
Previously the mkdir_label() family of calls was implemented in
src/shared/mkdir-label.c but its functions partly declared ins
src/shared/label.h and partly in src/basic/mkdir.h (!!). That's weird
(and wrong).
Let's clean this up, and add a proper mkdir-label.h matching the .c
file.
Let's reduce our code duplication, and let's focus on using xyzat()
style APIs more, hence drop mkdir_errno_wrapper() and stick to
mkdirar_errno_wrapper() wherever we can, it's a true superset of
functionality after all.
Let's keep the comments together with the lines they describe, this is easier
to read and probably more maintainable in the long run.
Also, () → {} for idiomaticity.
This new helper converts libc style syscall return values into
systemd-kernel (actually: kernel style) negative errno values.
It's implemented as macro-like inline function, and propagates return
values >= 0 as themselves and returns -errno for negative error returns.
THis is supposed to be little more than syntactic sugar so that we can
reduce a lot of (short, but still) boilerplate code whever we convert
libc style error handling into our own.
As discussed here:
https://github.com/systemd/systemd/pull/21326#discussion_r748413537
smb3 is an alias for modern CIFS, not the old SMB fs (see kmod alias list, i.e. modinfo fs-smb3).
(the old smbfs has long been removed from the kernel actually, it's dead
and obsolete)
devtmpfs and cpuset are not actual filesystems of their own. cpuset used
to be but is now an alias for cgroupsfs. devtmpfs is the same as tmpfs
as its just a "named superblock", i.e. a specific instance of tmpfs, but
not a file system of its own.
This group shall cover file systems whose job is to make stuff that
isn't actually storing anything in itself, and isn't just an API file
system, but allows exposing stuff with special semantics in the VFS.
1. @anonymous → for file systems that aren't real file systems but
simply the backing for sockets, pipes and other "anonymous" fds.
2. @security → for the various MAC security file systems.
Daan De Meyer
Lennart Poettering
Zbigniew Jędrzejewski-Szmek
Yu Watanabe