Add initial implementation of OpenRC manager module

1 files changed, 259 insertions, 0 deletions

diff --git a/ncserver/module/openrc.py b/ncserver/module/openrc.py
new file mode 100644
index 0000000..60f6c7f
--- /dev/null
+++ b/ncserver/module/openrc.py
@@ -0,0 +1,259 @@
+"""
+NETCONF for APK Distributions server:
+    adelie-services module, OpenRC edition
+
+Copyright © 2020 Adélie Software in the Public Benefit, Inc.
+
+Released under the terms of the NCSA license.  See the LICENSE file included
+with this source distribution for more information.
+
+SPDX-License-Identifier: NCSA
+"""
+
+import errno
+import logging
+import os
+import pathlib
+import subprocess
+
+from lxml import etree
+from netconf import error, util
+
+from ncserver.base.service import Service, ServiceStatus
+from ncserver.base.util import _
+
+
+QName = etree.QName  # pylint: disable=I1101
+
+
+LOGGER = logging.getLogger(__name__)
+"""The object used for logging informational messages."""
+
+
+M_ABI_VERSION = 1
+"""The ABI version of this NETCONF module."""
+
+
+M_PREFIX = "svcs"
+"""The XML tag prefix for this module's tags."""
+
+
+M_NS = "http://netconf.adelielinux.org/ns/service"
+"""The XML namespace for this module."""
+
+
+M_NAME = "adelie-services"
+"""The YANG model name for this module."""
+
+
+M_REVISION = "2020-09-22"
+"""The YANG revision date for this module."""
+
+
+M_IMPORTS = {
+    'ietf-yang-types@2013-07-15': {
+        'ns': "urn:ietf:params:xml:ns:yang:ietf-yang-types", 'prefix': "yang"
+    }
+}
+"""The imported YANG modules for this module."""
+
+
+def valid_name(name):
+    """Determine if the given name is a valid OpenRC service name."""
+    valid = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890_-."
+    return all(char in valid for char in name)
+
+
+def is_enabled(name):
+    """Determine if this OpenRC service is enabled."""
+    runlevels = (pathlib.Path('/etc/runlevels/boot'),
+                 pathlib.Path('/etc/runlevels/sysinit'),
+                 pathlib.Path('/etc/runlevels/default'))
+    for level in runlevels:
+        for service in level.iterdir():
+            # Resolve the symlink.  If it's the service name, we have a match.
+            if pathlib.Path(service).resolve().name == name:
+                return True
+    return False
+
+
+def get_var(shell_like, var_name: str, default="") -> str:
+    """Retrieve the value of var_name from a shell script-like file shell_like.
+
+    :param shell_like:
+    The path to the shell script-like file.
+
+    :param str var_name:
+    The name of the variable to extract.
+
+    :param str default:
+    The default value to return if the variable is not set.
+    """
+    script = ". /etc/init.d/functions.sh; ( . {shlike} && printf %s \"${var}\" )"
+    script = script.format(shlike=shell_like, var=var_name)
+    proc = subprocess.run(['/bin/sh', '-e', '-c', script],
+            stdout=subprocess.PIPE, check=True, env={'SHDIR':'/etc/init.d'},
+            stderr=subprocess.PIPE
+    )
+    value = proc.stdout.decode('utf-8')
+    if value == "":
+        return default
+    return value
+
+
+def check_alive(pidfile) -> bool:
+    """Determine if the PID contained in a pidfile is alive."""
+    pid = 0
+    try:
+        with open(pidfile) as fhandle:
+            pid = int(fhandle.read().rstrip())
+    except OSError as ose:
+        if ose.errno == errno.EPERM or ose.errno == errno.EACCES:
+            return True  # the pidfile cannot be accessed
+        return False  # sounds bad to me
+    except ValueError:
+        return False  # the pidfile doesn't contain a PID
+
+    if pid <= 0:
+        return False
+
+    try:
+        os.kill(pid, 0)
+    except OSError as ose:
+        if ose.errno == errno.EPERM:
+            return True  # we can't send signal because it's alive
+        return False
+    else:
+        return True
+
+
+class OpenRCService(Service):
+    """The OpenRC implementation of the Service class."""
+    def __init__(self, name):
+        """Initialise the structure."""
+        super().__init__()
+
+        if not valid_name(name):
+            raise NameError(_("{}: invalid service name").format(name))
+
+        svcpath = "/etc/init.d/{name}".format(name=name)
+        if not os.path.exists(svcpath):
+            raise ValueError(_("{} does not exist").format(name))
+
+        self._name = name
+        self._description = get_var(svcpath, "description", name)
+        self._enabled = is_enabled(name)
+
+    def status(self):
+        """Retrieve the service's status."""
+        stat = ServiceStatus.Stopped
+
+        status_dirs = {
+                ServiceStatus.Starting: "/run/openrc/starting",
+                ServiceStatus.Running: "/run/openrc/started",
+                ServiceStatus.Stopping: "/run/openrc/stopping"
+        }
+
+        for value, directory in status_dirs.items():
+            for service in pathlib.Path(directory).iterdir():
+                if pathlib.Path(service).resolve().name == self.name:
+                    stat = value
+                    break
+
+        if stat == ServiceStatus.Running:
+            # Check if crashed
+            for service in pathlib.Path("/run/openrc/daemons").iterdir():
+                svcdir = pathlib.Path(service)
+                if svcdir.name == self.name:
+                    for daemon in svcdir.iterdir():
+                        dpid = get_var(daemon, 'pidfile')
+                        if dpid and not check_alive(dpid):
+                            return ServiceStatus.Crashed
+
+        return stat
+
+    def start(self):
+        """Start the service."""
+        if self.status() in (ServiceStatus.Starting, ServiceStatus.Running):
+            return
+
+        subprocess.Popen(["/sbin/rc-service", self.name, "start"])
+
+    def stop(self):
+        """Stop the service."""
+        subprocess.Popen(["/sbin/rc-service", self.name, "stop"])
+
+    def reload(self):
+        """Reload the service's configuration, if possible."""
+
+    def restart(self, full: bool):
+        """Restart the service.
+
+        OpenRC does not support a concept of full restart, so this parameter
+        is always ignored.
+        """
+        subprocess.Popen(["/sbin/rc-service", self.name, "restart"])
+
+    def __str__(self):
+        return self.name
+
+    def __repr__(self):
+        return "<OpenRC service {name} ({status})>".format(
+                name=self.name, status=self.status()
+        )
+
+
+def service_list():
+    """Return the list of services available on this device."""
+    services = list()
+
+    for service in pathlib.Path('/etc/init.d').iterdir():
+        if service.suffix == '.sh':
+            continue
+
+        services.append(OpenRCService(service.name))
+
+    return services
+
+
+def info(service: str) -> OpenRCService:
+    """Return the Service object associated with the specified service.
+
+    :param str service:
+    The name of the service to look up.
+
+    :returns:
+    The Service object, or None if a service with that name does not exist.
+    """
+    try:
+        return OpenRCService(service)
+    except ValueError:
+        return None
+
+
+def running(node):
+    """Retrieve the service configuration for this device."""
+    svcs = util.subelm(node, 'svcs:services')
+
+    for service in service_list():
+        svcnode = util.subelm(svcs, 'svcs:service')
+        svcnode.append(util.leaf_elm('svcs:name', service.name))
+        svcnode.append(util.leaf_elm('svcs:enabled', service.enabled))
+
+
+def operational(node):
+    """Retrieve the service state for this device."""
+    svcs = util.subelm(node, 'svcs:services')
+
+    for service in service_list():
+        svcnode = util.subelm(svcs, 'svcs:service')
+        svcnode.append(util.leaf_elm('svcs:name', service.name))
+        svcnode.append(util.leaf_elm('svcs:description', service.description))
+        svcnode.append(util.leaf_elm('svcs:enabled', service.enabled))
+        svcnode.append(util.leaf_elm(
+            'svcs:status', service.status().name.lower()
+        ))
+
+
+def edit(rpc, node, def_op):
+    """Edit the service configuration for this device."""