Taking a stab at implementing #14479.
Add {Condition,Assert}CPUFeature to `systemd-analyze` & friends. Implement it
by executing the CPUID instruction. Add tables for common x86/i386
features.
Tested via unit tests + checked that commands such as:
```bash
systemd-analyze condition 'AssertCPUFeature = rdrand'
```
Succeed as expected and that commands such as
```bash
systemd-analyze condition 'AssertCPUFeature = foobar'
```
Fail as expected. Finally, I have amended the `systemd.unit` manual page
with the new condition and the list of all currently supported flags.
We provide a way via the '-' symbol to ignore errors when nonexistent
executable files are passed to Exec* parameters & so on. In such a case,
the flag `EXEC_COMMAND_IGNORE_FAILURE` is set and we go on happily with
our life if that happens. However, `systemd-analyze verify` complained
about missing executables even in such a case. In such a case it is not
an error for this to happen so check if the flag is set before checking
if the file is accessible and executable.
Add some small tests to check this condition.
Closes#15218.
On certain distributions such as NixOS the mtime of `/etc/hosts` is
locked to a fixed value. In such cases, only checking the last mtime of
`/etc/hosts` is not enough - we also need to check if the st_ino/st_dev
match up. Thus, let's make sure make sure that systemd-resolved also
rereads `/etc/hosts` if the inode or the device containing `/etc/hosts` changes.
Test script:
```bash
hosts="/etc/hosts"
echo "127.0.0.1 testpr" > "hosts_new"
mv "hosts_new" "$hosts"
resolvectl query testpr || exit 1
mtime="$(stat -c %y "$hosts")"
echo "127.0.0.1 newhost" > "hosts_tmp"
touch -d "$mtime" "hosts_tmp"
install -p "hosts_tmp" "$hosts"
sleep 10
resolvectl query newhost || exit 1
rm -f "hosts_tmp"
```
Closes#14456.
Add a simple check on the number of unit files that were found: return
`-ENOENT` when none is found from the function and thus `systemctl`
consequently exits with `1` (`EXIT_FAILURE`) if none were found.
Verification:
```bash
root@image:~# systemctl list-unit-files dbus-nonexistant.service; echo
$?
UNIT FILE STATE VENDOR PRESET
0 unit files listed.
1
root@image:~# systemctl list-unit-files dbus.service; echo $?
UNIT FILE STATE VENDOR PRESET
dbus.service static enabled
1 unit files listed.
0
```
Fixes#15082.
It is useful to know when a timer will trigger next when looking at a
timer status message so calculate and print that information.
Closes#5738.
Example output:
$ systemctl status dnf-makecache.timer
● dnf-makecache.timer - dnf makecache timer
Loaded: loaded (/usr/lib/systemd/system/dnf-makecache.timer; enabled; vendor preset: enabled)
Active: active (waiting) since Tue 2017-07-04 17:24:02 EDT; 24min ago
Trigger: Tue 2017-07-04 18:15:56 EDT; 27min left
Giedrius Statkevičius