Resolve /etc/machine-id before checking the mount state and before
writing back, so symlinked targets are committed correctly.
Fixes: #43104
Follow-up for: efabf4e044
git grep -l 'Failed to open /'|xargs sed -r -i 's|"Failed to open (/[^ ]+): %m"|"Failed to open %s: %m", "\1"|g'
git grep -l $'Failed to open \'/'|xargs sed -r -i $'s|"Failed to open \'(/[^ ]+)\': %m"|"Failed to open %s: %m", "\\1"|g'
git grep -l "Failed to open /"|xargs sed -r -i $'s|"Failed to open (/[^ ]+), ignoring: %m"|"Failed to open %s, ignoring: %m", "\\1"|g'
+ some manual fixups.
This also implies the new CHASE_MUST_BE_DIRECTORY flag in case the
specified path ends in a slash. This makes the rules stricter, it means
we'll be closer to how this is handled in kernel: if a path ends in a
slash it can never refer to a non-directory.
If we operate relative some explicit rootfs the reason for the sync()ing
is not really given, we are not really acting as a milestone at boot,
but "offline".
If an initrd has an empty or uninitialized /etc/machine-id file,
then PID1 write a valid machine ID. So, the logic is important only on
soft-reboot. Let's mention that explicitly.
Follow-up for 16718dcf78.
This effectively reverts ba540e9f1c.
https://github.com/systemd/systemd/pull/32915#discussion_r1608258136
> In many cases we allow --root=/ as a mechanism for forcing an "offline" mode,
> while still operating on the root dir. if we do the getenv_for_pid() thing
> below I'd claim this is very much an "online" operation, and hence --root=/
> should really disable that.
If machine ID is previously stored at /run/machine-id, then let's reuse
it. This is important on switching root and /etc/machine-id was previously
a mount point.
Fixes#32908.
Similar as the previous commit, it's useful for a supervisor to know
what machine ID we settlted on, in particular as various other things
are deterministically derived from it, for example MAC addresses and
such.
We usually check return value of syscalls or glibc functions by it is
negative or not, something like that `if (stat(path, &st) < 0)`.
Let's also use the same style for lseek() and friends even the type of
their return value is off_t.
Note, fseeko() returns int, instead of off_t.
Let's hook up one more thing with credentials: the machine ID to use
when none is initialized yet.
This requires some reordering of initialization steps in PID 1: we need
to import credentials first, and only then initialize the machine ID.
If a root directory is specified, and e.g. /var under the root directory
is a symlink to the host's /var, then we wrongly read host's machine ID,
even if O_NOFOLLOW is set.
Let's chase the path with CHASE_NOFOLLOW to refuse such case.
Also, refuse null ID, otherwise we may setup machine ID with NULL.
-1 was used everywhere, but -EBADF or -EBADFD started being used in various
places. Let's make things consistent in the new style.
Note that there are two candidates:
EBADF 9 Bad file descriptor
EBADFD 77 File descriptor in bad state
Since we're initializating the fd, we're just assigning a value that means
"no fd yet", so it's just a bad file descriptor, and the first errno fits
better. If instead we had a valid file descriptor that became invalid because
of some operation or state change, the other errno would fit better.
In some places, initialization is dropped if unnecessary.
RUN_WITH_UMASK was initially conceived for spawning externals progs with the
umask set. But nowadays we use it various syscalls and stuff that doesn't "run"
anything, so the "RUN_" prefix has outlived its usefulness.
Same idea as 03677889f0.
No functional change intended. The type of the iterator is generally changed to
be 'const char*' instead of 'char*'. Despite the type commonly used, modifying
the string was not allowed.
I adjusted the naming of some short variables for clarity and reduced the scope
of some variable declarations in code that was being touched anyway.