1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
|
import os
import subprocess
# get-timesync-backend - determine which NTP backend unit timedatectl
# will likely enable.
roots = ["/etc", "/run", "/usr/local", "/usr/lib", "/lib"]
def gather_files(name, suffix):
# This function creates a list of files in the same order that
# systemd will read them in.
#
# First we collect all files in all root directories. Duplicates
# are avoided by only storing files with a basename that hasn't
# been seen yet. The roots are processed in order so that files
# in /etc override identically named files in /usr, for example.
#
# The files are stored in a dict with their basename (such as
# "10-chrony.list") as the key and their full pathname (such as
# "/usr/lib/systemd/ntp-units.d/10-chrony.list") as the value.
#
# This arrangement allows for easy checks for duplicate basenames
# while retaining access to the full pathname later when creating
# the final result.
#
pathname_by_basename = {}
for r in roots:
dirname = os.path.join(r, name)
if os.path.isdir(dirname):
for basename in os.listdir(dirname):
if basename.endswith(suffix) and basename not in pathname_by_basename:
pathname_by_basename[basename] = os.path.join(dirname, basename)
# Then we create a list of the full pathnames, sorted by their
# basenames.
#
sorted_basenames = sorted(pathname_by_basename.keys())
return [pathname_by_basename[basename] for basename in sorted_basenames]
def unit_exists(unit):
load_state = subprocess.check_output(["systemctl", "show", "--value", "-p", "LoadState", unit],
universal_newlines=True).strip()
return load_state != "not-found" and load_state != "masked"
def first_unit(files):
for f in files:
with open(f) as c:
for ll in c.readlines():
w = ll.strip()
if w != "" and not w.startswith("#") and unit_exists(w):
return w
return None
unit = first_unit(gather_files("systemd/ntp-units.d", ".list"))
if unit:
print(unit)
|
