A pid can be recycled, but a pidfd is pinned. Add a new method that is safer
as it takes a pidfd as input.
Return not only the D-Bus object path, but also the unit id and the last
recorded invocation id, as they are both useful (especially the id, as
converting from a path object to a unit id from a script requires another
round-trip via D-Bus).
Note that the manager still tracks processes by pid, so theorethically this
is not fully error-proof, but on the other hand the method response is
synchronous and the manager is single-threaded, so once a call is being
processed the unit database will not change anyway. Once the manager
switches to use pidfds everywhere, this can be further hardened.
When we operate with DDIs with sector sizes != 512 we need to configure
the loopback device to match it, otherwise the image and the kernel
block device will disagree what things are.
Let's add a prober that tries to determine the sector size of a GPT DDI.
It does this by looking for the GPT partition table header at the
various byte offsets they must be located on, given a specific sector
size. It will try sector size 512, 1024, 2048 and 4096. Of these only
the 512 and 4096 really make sense IRL I guess, but let's be thorough.
Given that we already have the file descriptor opened for writing, it
would make sense to call fstatvfs with that file descriptor rather than
statvfs with the directory path that was used to open that descriptor.
Let's allow users to configure the (logical) sector size of their
image. This is required when building images for a 4k sector size
disk on a 512b sector size host or vice-versa.
This fixes 3e87a057a7, which passed the
path to the wrong Print() call. Miraculously, this was printing the
correct path during testing and was therefore missed.
since we don't have systemd-pcrphase built anyway, which breaks the tests:
...
I: Attempting to install /usr/lib/systemd/systemd-networkd-wait-online (based on unit file reference)
I: Attempting to install /usr/lib/systemd/systemd-network-generator (based on unit file reference)
I: Attempting to install /usr/lib/systemd/systemd-oomd (based on unit file reference)
I: Attempting to install /usr/lib/systemd/systemd-pcrphase (based on unit file reference)
W: Failed to install '/usr/lib/systemd/systemd-pcrphase'
make: *** [Makefile:4: setup] Error 1
make: Leaving directory '/root/systemd/test/TEST-01-BASIC'
Follow-up to 04959faa63.
