systemd-python: add systemd.daemon wrapping sd-daemon

Please see the documentation (e.g. pydoc3 systemd.daemon) for full
description. As usual, systemd._daemon wraps the raw interface, while
systemd.daemon provides the more pythonic API. sd_listen_fds,
sd_booted, sd_is_fifo, sd_is_socket, sd_is_socket_unix,
sd_is_socket_inet, sd_is_mq, and SD_LISTEN_FDS_START are currently
wrapped.

Makefile.am

@@ -3484,6 +3484,7 @@ if HAVE_PYTHON_DEVEL
 pkgpyexec_LTLIBRARIES = \
 	_journal.la \
 	id128.la \
+	_daemon.la \
 	_reader.la
 
 _journal_la_SOURCES = \
@@ -3526,6 +3527,27 @@ id128_la_LIBADD = \
 	$(PYTHON_LIBS) \
 	libsystemd-id128.la
 
+_daemon_la_SOURCES = \
+	src/python-systemd/_daemon.c \
+	src/python-systemd/pyutil.c \
+	src/python-systemd/pyutil.h
+
+_daemon_la_CFLAGS = \
+	$(AM_CFLAGS) \
+        -fvisibility=default \
+	$(PYTHON_CFLAGS) \
+	-I$(top_builddir)/src/python-systemd
+
+_daemon_la_LDFLAGS = \
+	$(AM_LDFLAGS) \
+	-shared \
+	-module \
+	-avoid-version
+
+_daemon_la_LIBADD = \
+	$(PYTHON_LIBS) \
+	libsystemd-daemon.la
+
 _reader_la_SOURCES = \
 	src/python-systemd/_reader.c \
 	src/python-systemd/pyutil.c \
@@ -3550,6 +3572,7 @@ _reader_la_LIBADD = \
 
 dist_pkgpyexec_PYTHON = \
 	src/python-systemd/journal.py \
+	src/python-systemd/daemon.py \
 	src/python-systemd/__init__.py
 
 src/python-systemd/id128-constants.h: src/systemd/sd-messages.h Makefile

TODO

@@ -587,6 +587,7 @@ Features:
      be just "return self->j != NULL")
    - figure out a simple way to wait for journal events in a way that
      works with ^C
+   - add documentation to systemd.daemon
 
 External:
 

src/python-systemd/_daemon.c

@@ -0,0 +1,323 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2013 Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#define PY_SSIZE_T_CLEAN
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wredundant-decls"
+#include <Python.h>
+#pragma GCC diagnostic pop
+
+#include <stdbool.h>
+#include <assert.h>
+#include <sys/socket.h>
+
+#include <systemd/sd-daemon.h>
+#include "pyutil.h"
+
+PyDoc_STRVAR(module__doc__,
+        "Python interface to the libsystemd-daemon library.\n\n"
+        "Provides _listen_fds, notify, booted, and is_* functions\n"
+        "which wrap sd_listen_fds, sd_notify, sd_booted, sd_is_* and\n"
+        "useful for socket activation and checking if the system is\n"
+        "running under systemd."
+);
+
+static PyObject* set_error(int r, const char* invalid_message) {
+        assert (r < 0);
+
+        if (r == -EINVAL && invalid_message)
+                PyErr_SetString(PyExc_ValueError, invalid_message);
+        else if (r == -ENOMEM)
+                PyErr_SetString(PyExc_MemoryError, "Not enough memory");
+        else {
+                errno = -r;
+                PyErr_SetFromErrno(PyExc_OSError);
+        }
+
+        return NULL;
+}
+
+
+#if PY_MAJOR_VERSION >=3 && PY_MINOR_VERSION >= 1
+static int Unicode_FSConverter(PyObject* obj, void *_result) {
+        PyObject **result = _result;
+
+        assert(result);
+
+        if (!obj)
+                /* cleanup: we don't return Py_CLEANUP_SUPPORTED, so
+                 * we can assume that it was PyUnicode_FSConverter. */
+                return PyUnicode_FSConverter(obj, result);
+
+        if (obj == Py_None) {
+                *result = NULL;
+                return 1;
+        }
+
+        return PyUnicode_FSConverter(obj, result);
+}
+#endif
+
+
+PyDoc_STRVAR(booted__doc__,
+             "booted() -> bool\n\n"
+             "Return True iff this system is running under systemd.\n"
+             "Wraps sd_daemon_booted(3)."
+);
+
+static PyObject* booted(PyObject *self, PyObject *args) {
+        int r;
+        assert(args == NULL);
+
+        r = sd_booted();
+        if (r < 0)
+                return set_error(r, NULL);
+
+        return PyBool_FromLong(r);
+}
+
+
+PyDoc_STRVAR(listen_fds__doc__,
+             "_listen_fds(unset_environment=True) -> int\n\n"
+             "Return the number of descriptors passed to this process by the init system\n"
+             "as part of the socket-based activation logic.\n"
+             "Wraps sd_listen_fds(3)."
+);
+
+static PyObject* listen_fds(PyObject *self, PyObject *args) {
+        int r;
+        int unset = true;
+
+#if PY_MAJOR_VERSION >=3 && PY_MINOR_VERSION >= 3
+        if (!PyArg_ParseTuple(args, "|p:_listen_fds", &unset))
+                return NULL;
+#else
+        PyObject *obj = NULL;
+        if (!PyArg_ParseTuple(args, "|O:_listen_fds", &obj))
+                return NULL;
+        if (obj != NULL)
+                unset = PyObject_IsTrue(obj);
+        if (unset < 0)
+                return NULL;
+#endif
+
+        r = sd_listen_fds(unset);
+        if (r < 0)
+                return set_error(r, NULL);
+
+        return long_FromLong(r);
+}
+
+PyDoc_STRVAR(is_fifo__doc__,
+             "_is_fifo(fd, path) -> bool\n\n"
+             "Returns True iff the descriptor refers to a FIFO or a pipe.\n"
+             "Wraps sd_is_fifo(3)."
+);
+
+
+static PyObject* is_fifo(PyObject *self, PyObject *args) {
+        int r;
+        int fd;
+        const char *path = NULL;
+
+#if PY_MAJOR_VERSION >=3 && PY_MINOR_VERSION >= 1
+        if (!PyArg_ParseTuple(args, "i|O&:_is_fifo",
+                              &fd, Unicode_FSConverter, &path))
+                return NULL;
+#else
+        if (!PyArg_ParseTuple(args, "i|z:_is_fifo", &fd, &path))
+                return NULL;
+#endif
+
+        r = sd_is_fifo(fd, path);
+        if (r < 0)
+                return set_error(r, NULL);
+
+        return PyBool_FromLong(r);
+}
+
+
+PyDoc_STRVAR(is_mq__doc__,
+             "_is_mq(fd, path) -> bool\n\n"
+             "Returns True iff the descriptor refers to a POSIX message queue.\n"
+             "Wraps sd_is_mq(3)."
+);
+
+static PyObject* is_mq(PyObject *self, PyObject *args) {
+        int r;
+        int fd;
+        const char *path = NULL;
+
+#if PY_MAJOR_VERSION >=3 && PY_MINOR_VERSION >= 1
+        if (!PyArg_ParseTuple(args, "i|O&:_is_mq",
+                              &fd, Unicode_FSConverter, &path))
+                return NULL;
+#else
+        if (!PyArg_ParseTuple(args, "i|z:_is_mq", &fd, &path))
+                return NULL;
+#endif
+
+        r = sd_is_mq(fd, path);
+        if (r < 0)
+                return set_error(r, NULL);
+
+        return PyBool_FromLong(r);
+}
+
+
+
+PyDoc_STRVAR(is_socket__doc__,
+             "_is_socket(fd, family=AF_UNSPEC, type=0, listening=-1) -> bool\n\n"
+             "Returns True iff the descriptor refers to a socket.\n"
+             "Wraps sd_is_socket(3).\n\n"
+             "Constants for `family` are defined in the socket module."
+);
+
+static PyObject* is_socket(PyObject *self, PyObject *args) {
+        int r;
+        int fd, family = AF_UNSPEC, type = 0, listening = -1;
+
+        if (!PyArg_ParseTuple(args, "i|iii:_is_socket",
+                              &fd, &family, &type, &listening))
+                return NULL;
+
+        r = sd_is_socket(fd, family, type, listening);
+        if (r < 0)
+                return set_error(r, NULL);
+
+        return PyBool_FromLong(r);
+}
+
+
+PyDoc_STRVAR(is_socket_inet__doc__,
+             "_is_socket_inet(fd, family=AF_UNSPEC, type=0, listening=-1, port=0) -> bool\n\n"
+             "Wraps sd_is_socket_inet(3).\n\n"
+             "Constants for `family` are defined in the socket module."
+);
+
+static PyObject* is_socket_inet(PyObject *self, PyObject *args) {
+        int r;
+        int fd, family = AF_UNSPEC, type = 0, listening = -1, port = 0;
+
+        if (!PyArg_ParseTuple(args, "i|iiii:_is_socket_inet",
+                              &fd, &family, &type, &listening, &port))
+                return NULL;
+
+        if (port < 0 || port > INT16_MAX)
+                return set_error(-EINVAL, "port must fit into uint16_t");
+
+        r = sd_is_socket_inet(fd, family, type, listening, (uint16_t) port);
+        if (r < 0)
+                return set_error(r, NULL);
+
+        return PyBool_FromLong(r);
+}
+
+
+PyDoc_STRVAR(is_socket_unix__doc__,
+             "_is_socket_unix(fd, type, listening, path) -> bool\n\n"
+             "Wraps sd_is_socket_unix(3)."
+);
+
+static PyObject* is_socket_unix(PyObject *self, PyObject *args) {
+        int r;
+        int fd, type = 0, listening = -1;
+        char* path = NULL;
+        Py_ssize_t length = 0;
+
+#if PY_MAJOR_VERSION >=3 && PY_MINOR_VERSION >= 1
+        PyObject _cleanup_Py_DECREF_ *_path = NULL;
+        if (!PyArg_ParseTuple(args, "i|iiO&:_is_socket_unix",
+                              &fd, &type, &listening, Unicode_FSConverter, &_path))
+                return NULL;
+        if (_path) {
+                assert(PyBytes_Check(_path));
+                if (PyBytes_AsStringAndSize(_path, &path, &length))
+                        return NULL;
+        }
+#else
+        if (!PyArg_ParseTuple(args, "i|iiz#:_is_socket_unix",
+                              &fd, &type, &listening, &path, &length))
+                return NULL;
+#endif
+
+        r = sd_is_socket_unix(fd, type, listening, path, length);
+        if (r < 0)
+                return set_error(r, NULL);
+
+        return PyBool_FromLong(r);
+}
+
+
+static PyMethodDef methods[] = {
+        { "booted", booted, METH_NOARGS, booted__doc__},
+        { "_listen_fds", listen_fds, METH_VARARGS, listen_fds__doc__},
+        { "_is_fifo", is_fifo, METH_VARARGS, is_fifo__doc__},
+        { "_is_mq", is_mq, METH_VARARGS, is_mq__doc__},
+        { "_is_socket", is_socket, METH_VARARGS, is_socket__doc__},
+        { "_is_socket_inet", is_socket_inet, METH_VARARGS, is_socket_inet__doc__},
+        { "_is_socket_unix", is_socket_unix, METH_VARARGS, is_socket_unix__doc__},
+        { NULL, NULL, 0, NULL }        /* Sentinel */
+};
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wmissing-prototypes"
+
+#if PY_MAJOR_VERSION < 3
+
+PyMODINIT_FUNC init_daemon(void) {
+        PyObject *m;
+
+        m = Py_InitModule3("_daemon", methods, module__doc__);
+        if (m == NULL)
+                return;
+
+        PyModule_AddIntConstant(m, "LISTEN_FDS_START", SD_LISTEN_FDS_START);
+}
+
+#else
+
+static struct PyModuleDef module = {
+        PyModuleDef_HEAD_INIT,
+        "_daemon", /* name of module */
+        module__doc__, /* module documentation, may be NULL */
+        0, /* size of per-interpreter state of the module */
+        methods
+};
+
+PyMODINIT_FUNC PyInit__daemon(void) {
+        PyObject *m;
+
+        m = PyModule_Create(&module);
+        if (m == NULL)
+                return NULL;
+
+        if (PyModule_AddIntConstant(m, "LISTEN_FDS_START", SD_LISTEN_FDS_START)) {
+                Py_DECREF(m);
+                return NULL;
+        }
+
+        return m;
+}
+
+#endif
+
+#pragma GCC diagnostic pop

src/python-systemd/_reader.c

@@ -30,23 +30,6 @@
 #include "macro.h"
 #include "util.h"
 
-#if PY_MAJOR_VERSION >=3
-# define unicode_FromStringAndSize PyUnicode_FromStringAndSize
-# define unicode_FromString PyUnicode_FromString
-# define long_FromLong PyLong_FromLong
-# define long_FromSize_t PyLong_FromSize_t
-# define long_Check PyLong_Check
-# define long_AsLong PyLong_AsLong
-#else
-/* Python 3 type naming convention is used */
-# define unicode_FromStringAndSize PyString_FromStringAndSize
-# define unicode_FromString PyString_FromString
-# define long_FromLong PyInt_FromLong
-# define long_FromSize_t PyInt_FromSize_t
-# define long_Check PyInt_Check
-# define long_AsLong PyInt_AsLong
-#endif
-
 typedef struct {
     PyObject_HEAD
     sd_journal *j;

src/python-systemd/daemon.py

@@ -0,0 +1,53 @@
+from ._daemon import (booted,
+                      _listen_fds,
+                      _is_fifo,
+                      _is_socket,
+                      _is_socket_inet,
+                      _is_socket_unix,
+                      _is_mq,
+                      LISTEN_FDS_START)
+from socket import AF_UNSPEC as _AF_UNSPEC
+
+def _convert_fileobj(fileobj):
+    try:
+        return fileobj.fileno()
+    except AttributeError:
+        return fileobj
+
+def is_fifo(fileobj, path=None):
+    fd = _convert_fileobj(fileobj)
+    return _is_fifo(fd, path)
+
+def is_socket(fileobj, family=_AF_UNSPEC, type=0, listening=-1):
+    fd = _convert_fileobj(fileobj)
+    return _is_socket(fd, family, type, listening)
+
+def is_socket_inet(fileobj, family=_AF_UNSPEC, type=0, listening=-1, port=0):
+    fd = _convert_fileobj(fileobj)
+    return _is_socket_inet(fd, family, type, listening)
+
+def is_socket_unix(fileobj, type=0, listening=-1, path=None):
+    fd = _convert_fileobj(fileobj)
+    return _is_socket_unix(fd, type, listening, path)
+
+def is_mq(fileobj, path=None):
+    fd = _convert_fileobj(fileobj)
+    return _is_mq(fd, path)
+
+def listen_fds(unset_environment=True):
+    """Return a list of socket activated descriptors
+
+    Example::
+
+      (in primary window)
+      $ systemd-activate -l 2000 python3 -c \\
+          'from systemd.daemon import listen_fds; print(listen_fds())'
+      (in another window)
+      $ telnet localhost 2000
+      (in primary window)
+      ...
+      Execing python3 (...)
+      [3]
+    """
+    num = _listen_fds(unset_environment)
+    return list(range(LISTEN_FDS_START, LISTEN_FDS_START + num))

src/python-systemd/docs/daemon.rst

@@ -0,0 +1,16 @@
+`systemd.daemon` module
+=======================
+
+.. automodule:: systemd.daemon
+   :members:
+   :undoc-members:
+   :inherited-members:
+
+   .. autoattribute:: systemd.daemon.LISTEN_FDS_START
+
+   .. autofunction:: _listen_fds
+   .. autofunction:: _is_fifo
+   .. autofunction:: _is_socket
+   .. autofunction:: _is_socket_unix
+   .. autofunction:: _is_socket_inet
+   .. autofunction:: _is_mq

src/python-systemd/docs/index.rst

@@ -13,6 +13,7 @@ Contents:
 
    journal
    id128
+   daemon
 
 Indices and tables
 ==================

src/python-systemd/pyutil.h

@@ -1,5 +1,7 @@
 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
 
+#pragma once
+
 /***
   This file is part of systemd.
 
@@ -27,3 +29,20 @@
 void cleanup_Py_DECREFp(PyObject **p);
 
 #define _cleanup_Py_DECREF_ __attribute__((cleanup(cleanup_Py_DECREFp)))
+
+#if PY_MAJOR_VERSION >=3
+# define unicode_FromStringAndSize PyUnicode_FromStringAndSize
+# define unicode_FromString PyUnicode_FromString
+# define long_FromLong PyLong_FromLong
+# define long_FromSize_t PyLong_FromSize_t
+# define long_Check PyLong_Check
+# define long_AsLong PyLong_AsLong
+#else
+/* Python 3 type naming convention is used */
+# define unicode_FromStringAndSize PyString_FromStringAndSize
+# define unicode_FromString PyString_FromString
+# define long_FromLong PyInt_FromLong
+# define long_FromSize_t PyInt_FromSize_t
+# define long_Check PyInt_Check
+# define long_AsLong PyInt_AsLong
+#endif