fix configurable process->service mapping on systemd

sau/gentoo.py

@@ -4,6 +4,7 @@ import re
 
 import sau
 import sau.helpers
+import sau.services
 
 EIX_SYNC_PATH='/usr/bin/eix-sync'
 RC_SERVICE_PATH='/sbin/rc-service'
@@ -22,8 +23,7 @@ slot_re = re.compile(r'^(\(~\))?([^\(]+)(\([^\)]+\))$')
 def identify_service_from_bin(exe):
     log = logging.getLogger(sau.LOGNAME)
 
-    with open('/proc/1/comm', 'r') as f:
+    if sau.services.on_systemd():
-        if f.readline().strip() == 'systemd':
         init_script_re = re.compile(r'[^/]*(.*)\.service$')
     else:
         init_script_re = re.compile(r'/etc/init\.d/(.*)')
@@ -61,8 +61,7 @@ def identify_service_from_bin(exe):
 
 def restart_service(service):
     log = logging.getLogger(sau.LOGNAME)
-    with open('/proc/1/comm', 'r') as f:
+    if sau.services.on_systemd():
-        if f.readline().strip() == 'systemd':
         cmd = [ SYSTEMCTL, 'restart', service ]
     else:
         cmd = [ RC_SERVICE_PATH, service, 'restart' ]

sau/services.py

@@ -75,6 +75,16 @@ def _get_processes():
 
     return check_procs
 
+# Just return True if system is running on systemd
+def on_systemd():
+    try:
+        init_proc = psutil.Process(pid=1)
+        if init_proc.name() == 'systemd':
+            return True
+    except psutil.NoSuchProcess:
+        pass
+    return False
+
 def restart_services():
     log = logging.getLogger(sau.LOGNAME)
     platform = sau.platforms.get_platform()
@@ -84,14 +94,6 @@ def restart_services():
     # wait before the second test
     time.sleep(5)
 
-    on_systemd = False
-    try:
-        init_proc = psutil.Process(pid=1)
-        if init_proc.name() == 'systemd':
-            on_systemd = True
-    except psutil.NoSuchProcess:
-        pass
-
     # perform a second check to remove potential false positives
     service_procs = set()
     retest_procs = set()
@@ -105,7 +107,7 @@ def restart_services():
         except (psutil.NoSuchProcess, psutil.ZombieProcess, psutil.AccessDenied):
             # either of the above exceptions means the process has quit
             continue
-        if on_systemd:
+        if on_systemd():
             service_procs.add(proc)
         else:
             parent = _get_top_parent(proc)
@@ -128,35 +130,18 @@ def restart_services():
             log.debug('{} died before it could be restarted'.format(proc))
             continue
 
-        if on_systemd:
-            if proc.pid == 1:
-                log.info("Upgrade of systemd detected; doing daemon-reexec")
-                ret, _out, _err = sau.helpers.exec_cmd([ '/usr/bin/systemctl', 'daemon-reexec' ])
-                continue
-            ret, unit, err = sau.helpers.exec_cmd([ '/usr/bin/systemctl', 'whoami', f'{proc.pid}' ])
-            unit = unit.strip()
-            name, unit_type = unit.split('.')
-            if ret != 0:
-                log.debug(f'Non-success ({ret}) when checking unit for process: {err}')
-                continue
-            elif unit_type != 'service':
-                log.warning(f'not restarting non-service unit "{unit}"; owner of {proc}')
-            elif name.startswith('user@'):
-                log.warning(f'Not restarting user service {unit}; please log out and log in again')
-            else:
-                _ret, enabled, _err = sau.helpers.exec_cmd([ '/usr/bin/systemctl', 'is-enabled', unit ])
-                enabled = enabled.strip()
-                if enabled not in ('enabled', 'static'):
-                    log.warning(f'Unit {name}.service has enable status: {enabled} - will only restart "enabled" services')
-                else:
-                    service_name = name
-        else:
         service_name = _get_service_from_proc(proc)
 
         if not service_name:
             log.warning('no service for process {}'.format(proc))
             recommend_restart = True
             continue
+        if service_name == 'systemd':
+            log.info("Upgrade of systemd detected; doing daemon-reexec")
+            sau.helpers.exec_cmd([ '/usr/bin/systemctl', 'daemon-reexec' ])
+            continue
+        elif service_name == '@ignore':
+            continue
 
         services[proc_name] = service_name
         processes[service_name] = [proc]
@@ -209,6 +194,7 @@ def _get_service_restart_policy(service):
 def _get_service_from_proc(proc):
     conf = sau.config
     platform = sau.platforms.get_platform()
+    if not on_systemd():
         proc = _get_top_parent(proc)
     log = logging.getLogger(sau.LOGNAME)
     try:
@@ -216,14 +202,42 @@ def _get_service_from_proc(proc):
         service_exe = proc.exe()
     except (psutil.NoSuchProcess, psutil.ZombieProcess, psutil.AccessDenied):
         log.debug('{} died'.format(proc))
-        return None
+        return '@ignore'
 
     service_name = conf.get('processes', proc_name, fallback=None)
+    log.debug(f'configuration of process "{proc_name}" in config: "{service_name}"')
     if service_name == '':
         log.debug('Ignoring process {}'.format(proc))
-        return None
+        return '@ignore'
 
     if not service_name:
+        # Systemd has it's own way...
+        if on_systemd():
+            if proc.pid == 1:
+                return 'systemd'
+            ret, unit, err = sau.helpers.exec_cmd([ '/usr/bin/systemctl', 'whoami', f'{proc.pid}' ])
+            unit = unit.strip()
+            name, unit_type = unit.split('.')
+            if ret != 0:
+                log.debug(f'Non-success ({ret}) when checking unit for process: {err}')
+                return None
+            elif unit_type != 'service':
+                log.warning(f'not restarting non-service unit "{unit}"; owner of {proc}')
+                return None
+            elif name.startswith('user@'):
+                log.warning(f'Not restarting user service {unit}; please log out and log in again')
+                return None
+            else:
+                _ret, enabled, _err = sau.helpers.exec_cmd([ '/usr/bin/systemctl', 'is-enabled', unit ])
+                enabled = enabled.strip()
+                if enabled not in ('enabled', 'static'):
+                    log.warning(f'Unit {name}.service has enable status: {enabled} - will only restart "enabled" services')
+                    return None
+                else:
+                    return name
+            log.error(f'This should be an unreachable path when checking process {proc}')
+            return None
+
         # if the exe file has been deleted since started, service_exe will be empty
         # and we'll have to guess
         if not service_exe: