Fix signal diff for truncated and RT signal names (#326)

* Fix signal diff for truncated and RT signal names

This refactors the signal mapping logic to closely resemble the logic in
podman.

Podman tolerates images with truncated STOPSIGNAL names e.g RTMIN+3
is used in the freeipa-container Dockerfiles.

Also avoids hardcoding real-time signals as they vary per
platform or glibc implementation (see man 7 signal).

* Cleanup lint

* More lint cleanup

plugins/module_utils/podman/common.py

@@ -7,6 +7,7 @@ __metaclass__ = type
 import json
 import os
 import shutil
+import signal
 
 
 def run_podman_command(module, executable='podman', args=None, expected_rc=0, ignore_errors=False):
@@ -96,3 +97,63 @@ def remove_file_or_dir(path):
         shutil.rmtree(path)
     else:
         raise ValueError("file %s is not a file or dir." % path)
+
+
+# Generated from https://github.com/containers/podman/blob/main/pkg/signal/signal_linux.go
+# and https://github.com/containers/podman/blob/main/pkg/signal/signal_linux_mipsx.go
+_signal_map = {
+    "ABRT": 6,
+    "ALRM": 14,
+    "BUS": 7,
+    "CHLD": 17,
+    "CLD": 17,
+    "CONT": 18,
+    "EMT": 7,
+    "FPE": 8,
+    "HUP": 1,
+    "ILL": 4,
+    "INT": 2,
+    "IO": 29,
+    "IOT": 6,
+    "KILL": 9,
+    "PIPE": 13,
+    "POLL": 29,
+    "PROF": 27,
+    "PWR": 30,
+    "QUIT": 3,
+    "RTMAX": int(signal.SIGRTMAX),
+    "RTMIN": int(signal.SIGRTMIN),
+    "SEGV": 11,
+    "STKFLT": 16,
+    "STOP": 19,
+    "SYS": 31,
+    "TERM": 15,
+    "TRAP": 5,
+    "TSTP": 20,
+    "TTIN": 21,
+    "TTOU": 22,
+    "URG": 23,
+    "USR1": 10,
+    "USR2": 12,
+    "VTALRM": 26,
+    "WINCH": 28,
+    "XCPU": 24,
+    "XFSZ": 25
+}
+
+for i in range(1, _signal_map['RTMAX'] - _signal_map['RTMIN'] + 1):
+    _signal_map['RTMIN+{0}'.format(i)] = _signal_map['RTMIN'] + i
+    _signal_map['RTMAX-{0}'.format(i)] = _signal_map['RTMAX'] - i
+
+
+def normalize_signal(signal_name_or_number):
+    signal_name_or_number = str(signal_name_or_number)
+    if signal_name_or_number.isdigit():
+        return signal_name_or_number
+    else:
+        signal_name = signal_name_or_number.upper()
+        if signal_name.startswith('SIG'):
+            signal_name = signal_name[3:]
+        if signal_name not in _signal_map:
+            raise RuntimeError("Unknown signal '{0}'".format(signal_name_or_number))
+        return str(_signal_map[signal_name])

plugins/module_utils/podman/podman_container_lib.py

@@ -6,6 +6,7 @@ from distutils.version import LooseVersion  # noqa: F402
 from ansible.module_utils._text import to_bytes, to_native  # noqa: F402
 from ansible_collections.containers.podman.plugins.module_utils.podman.common import lower_keys
 from ansible_collections.containers.podman.plugins.module_utils.podman.common import generate_systemd
+from ansible_collections.containers.podman.plugins.module_utils.podman.common import normalize_signal
 
 __metaclass__ = type
 
@@ -1152,47 +1153,8 @@ class PodmanContainerDiff:
         return self._diff_update_and_compare('security_opt', before, after)
 
     def diffparam_stop_signal(self):
-        signals = {
-            "sighup": "1",
-            "sigint": "2",
-            "sigquit": "3",
-            "sigill": "4",
-            "sigtrap": "5",
-            "sigabrt": "6",
-            "sigiot": "6",
-            "sigbus": "7",
-            "sigfpe": "8",
-            "sigkill": "9",
-            "sigusr1": "10",
-            "sigsegv": "11",
-            "sigusr2": "12",
-            "sigpipe": "13",
-            "sigalrm": "14",
-            "sigterm": "15",
-            "sigstkflt": "16",
-            "sigchld": "17",
-            "sigcont": "18",
-            "sigstop": "19",
-            "sigtstp": "20",
-            "sigttin": "21",
-            "sigttou": "22",
-            "sigurg": "23",
-            "sigxcpu": "24",
-            "sigxfsz": "25",
-            "sigvtalrm": "26",
-            "sigprof": "27",
-            "sigwinch": "28",
-            "sigio": "29",
-            "sigpwr": "30",
-            "sigsys": "31",
-            "sigrtmin+3": "37"
-        }
-        before = str(self.info['config']['stopsignal'])
-        if not before.isdigit():
-            before = signals[before.lower()]
-        after = str(self.params['stop_signal'])
-        if not after.isdigit():
-            after = signals[after.lower()]
+        before = normalize_signal(self.info['config']['stopsignal'])
+        after = normalize_signal(self.params['stop_signal'])
         return self._diff_update_and_compare('stop_signal', before, after)
 
     def diffparam_timezone(self):

tests/integration/targets/podman_container_idempotency/files/Dockerfile

@@ -21,7 +21,7 @@ EXPOSE 80
 EXPOSE 8080/tcp
 VOLUME ["/data", "/data2"]
 USER user
-STOPSIGNAL SIGKILL
+STOPSIGNAL KILL
 
 # problem with OS w/o systemd
 # HEALTHCHECK --interval=5m --timeout=3s \