Our CODING_STYLE suggests not comparing with NULL, but relying on C's
downgrade-to-bool feature for that. Fix up some code to match these
guidelines. (This is not comprehensive, the coccinelle output for this
is unfortunately kinda borked)
As we default to "hardware clock is in UTC" if /etc/adjtime is not present, it
also makes sense to have that default if /etc/adjtime contains only one or two
lines.
Drop the "gibberish" test case, as this was just EIO because of not containing
three lines, which is already contained in other tests. clock_is_localtime()
never actually validated the format of the first two lines, and there is little
point in doing that.
This addresses the reading half of issue #2638.
Add path argument to clock_is_localtime() and default to "/etc/adjtime" if it's
NULL. This makes the function testable.
Add test-clock: initial test cases for some scenarios, using a temporary file.
This also checks the behaviour with a NULL (i. e. the system's /etc/adjtime)
file.
For use in timesyncd we already defined a compile-time "epoch" value, which is based on the mtime of the NEWS file, and
specifies a point in time we know lies in the past at runtime. timesyncd uses this to filter out nonsensical timestamp
file data, and bump the system clock to a time that is after the build time of systemd. This patch adds similar bumping
code to earliest PID 1 initialization, so that the system never continues operation with a clock that is in the 1970ies
or even 1930s.
This is not particularly intrusive because it happens in simple
utility functions. It helps gcc understand that error codes
are negative.
This gets a rid of most of the remaining warnings.
There are more than enough calls doing string manipulations to deserve
its own files, hence do something about it.
This patch also sorts the #include blocks of all files that needed to be
updated, according to the sorting suggestions from CODING_STYLE. Since
pretty much every file needs our string manipulation functions this
effectively means that most files have sorted #include blocks now.
Also touches a few unrelated include files.
