1 files changed, 687 insertions, 0 deletions

diff --git a/src/modules/reserve.c b/src/modules/reserve.c
new file mode 100644
index 0000000..b0038e6
--- /dev/null
+++ b/src/modules/reserve.c
@@ -0,0 +1,687 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: t -*-*/
+
+/***
+  Copyright 2009 Lennart Poettering
+
+  Permission is hereby granted, free of charge, to any person
+  obtaining a copy of this software and associated documentation files
+  (the "Software"), to deal in the Software without restriction,
+  including without limitation the rights to use, copy, modify, merge,
+  publish, distribute, sublicense, and/or sell copies of the Software,
+  and to permit persons to whom the Software is furnished to do so,
+  subject to the following conditions:
+
+  The above copyright notice and this permission notice shall be
+  included in all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+  BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+  ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+  CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+***/
+
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <assert.h>
+
+#include "reserve.h"
+
+struct rd_device {
+	int ref;
+
+	char *device_name;
+	char *application_name;
+	char *application_device_name;
+	char *service_name;
+	char *object_path;
+	int32_t priority;
+
+	DBusConnection *connection;
+
+	unsigned owning:1;
+	unsigned registered:1;
+	unsigned filtering:1;
+	unsigned gave_up:1;
+
+	rd_request_cb_t request_cb;
+	void *userdata;
+};
+
+#define SERVICE_PREFIX "org.freedesktop.ReserveDevice1."
+#define OBJECT_PREFIX "/org/freedesktop/ReserveDevice1/"
+
+static const char introspection[] =
+	DBUS_INTROSPECT_1_0_XML_DOCTYPE_DECL_NODE
+	"<node>"
+	" <!-- If you are looking for documentation make sure to check out\n"
+	"      http://git.0pointer.de/?p=reserve.git;a=blob;f=reserve.txt -->\n"
+	" <interface name=\"org.freedesktop.ReserveDevice1\">"
+	"  <method name=\"RequestRelease\">"
+	"   <arg name=\"priority\" type=\"i\" direction=\"in\"/>"
+	"   <arg name=\"result\" type=\"b\" direction=\"out\"/>"
+	"  </method>"
+	"  <property name=\"Priority\" type=\"i\" access=\"read\"/>"
+	"  <property name=\"ApplicationName\" type=\"s\" access=\"read\"/>"
+	"  <property name=\"ApplicationDeviceName\" type=\"s\" access=\"read\"/>"
+	" </interface>"
+	" <interface name=\"org.freedesktop.DBus.Properties\">"
+	"  <method name=\"Get\">"
+	"   <arg name=\"interface\" direction=\"in\" type=\"s\"/>"
+	"   <arg name=\"property\" direction=\"in\" type=\"s\"/>"
+	"   <arg name=\"value\" direction=\"out\" type=\"v\"/>"
+	"  </method>"
+	" </interface>"
+	" <interface name=\"org.freedesktop.DBus.Introspectable\">"
+	"  <method name=\"Introspect\">"
+	"   <arg name=\"data\" type=\"s\" direction=\"out\"/>"
+	"  </method>"
+	" </interface>"
+	"</node>";
+
+static dbus_bool_t add_variant(
+	DBusMessage *m,
+	int type,
+	const void *data) {
+
+	DBusMessageIter iter, sub;
+	char t[2];
+
+	t[0] = (char) type;
+	t[1] = 0;
+
+	dbus_message_iter_init_append(m, &iter);
+
+	if (!dbus_message_iter_open_container(&iter, DBUS_TYPE_VARIANT, t, &sub))
+		return FALSE;
+
+	if (!dbus_message_iter_append_basic(&sub, type, data))
+		return FALSE;
+
+	if (!dbus_message_iter_close_container(&iter, &sub))
+		return FALSE;
+
+	return TRUE;
+}
+
+static DBusHandlerResult object_handler(
+	DBusConnection *c,
+	DBusMessage *m,
+	void *userdata) {
+
+	rd_device *d;
+	DBusError error;
+	DBusMessage *reply = NULL;
+
+	dbus_error_init(&error);
+
+	d = userdata;
+	assert(d->ref >= 1);
+
+	if (dbus_message_is_method_call(
+		    m,
+		    "org.freedesktop.ReserveDevice1",
+		    "RequestRelease")) {
+
+		int32_t priority;
+		dbus_bool_t ret;
+
+		if (!dbus_message_get_args(
+			    m,
+			    &error,
+			    DBUS_TYPE_INT32, &priority,
+			    DBUS_TYPE_INVALID))
+			goto invalid;
+
+		ret = FALSE;
+
+		if (priority > d->priority && d->request_cb) {
+			d->ref++;
+
+			if (d->request_cb(d, 0) > 0) {
+				ret = TRUE;
+				d->gave_up = 1;
+			}
+
+			rd_release(d);
+		}
+
+		if (!(reply = dbus_message_new_method_return(m)))
+			goto oom;
+
+		if (!dbus_message_append_args(
+			    reply,
+			    DBUS_TYPE_BOOLEAN, &ret,
+			    DBUS_TYPE_INVALID))
+			goto oom;
+
+		if (!dbus_connection_send(c, reply, NULL))
+			goto oom;
+
+		dbus_message_unref(reply);
+
+		return DBUS_HANDLER_RESULT_HANDLED;
+
+	} else if (dbus_message_is_method_call(
+			   m,
+			   "org.freedesktop.DBus.Properties",
+			   "Get")) {
+
+		const char *interface, *property;
+
+		if (!dbus_message_get_args(
+			    m,
+			    &error,
+			    DBUS_TYPE_STRING, &interface,
+			    DBUS_TYPE_STRING, &property,
+			    DBUS_TYPE_INVALID))
+			goto invalid;
+
+		if (strcmp(interface, "org.freedesktop.ReserveDevice1") == 0) {
+			const char *empty = "";
+
+			if (strcmp(property, "ApplicationName") == 0 && d->application_name) {
+				if (!(reply = dbus_message_new_method_return(m)))
+					goto oom;
+
+				if (!add_variant(
+					    reply,
+					    DBUS_TYPE_STRING,
+					    d->application_name ? (const char**) &d->application_name : &empty))
+					goto oom;
+
+			} else if (strcmp(property, "ApplicationDeviceName") == 0) {
+				if (!(reply = dbus_message_new_method_return(m)))
+					goto oom;
+
+				if (!add_variant(
+					    reply,
+					    DBUS_TYPE_STRING,
+					    d->application_device_name ? (const char**) &d->application_device_name : &empty))
+					goto oom;
+
+			} else if (strcmp(property, "Priority") == 0) {
+				if (!(reply = dbus_message_new_method_return(m)))
+					goto oom;
+
+				if (!add_variant(
+					    reply,
+					    DBUS_TYPE_INT32,
+					    &d->priority))
+					goto oom;
+			} else {
+				if (!(reply = dbus_message_new_error_printf(
+					      m,
+					      DBUS_ERROR_UNKNOWN_METHOD,
+					      "Unknown property %s",
+					      property)))
+					goto oom;
+			}
+
+			if (!dbus_connection_send(c, reply, NULL))
+				goto oom;
+
+			dbus_message_unref(reply);
+
+			return DBUS_HANDLER_RESULT_HANDLED;
+		}
+
+	} else if (dbus_message_is_method_call(
+			   m,
+			   "org.freedesktop.DBus.Introspectable",
+			   "Introspect")) {
+			    const char *i = introspection;
+
+		if (!(reply = dbus_message_new_method_return(m)))
+			goto oom;
+
+		if (!dbus_message_append_args(
+			    reply,
+			    DBUS_TYPE_STRING,
+			    &i,
+			    DBUS_TYPE_INVALID))
+			goto oom;
+
+		if (!dbus_connection_send(c, reply, NULL))
+			goto oom;
+
+		dbus_message_unref(reply);
+
+		return DBUS_HANDLER_RESULT_HANDLED;
+	}
+
+	return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
+
+invalid:
+	if (reply)
+		dbus_message_unref(reply);
+
+	if (!(reply = dbus_message_new_error(
+		      m,
+		      DBUS_ERROR_INVALID_ARGS,
+		      "Invalid arguments")))
+		goto oom;
+
+	if (!dbus_connection_send(c, reply, NULL))
+		goto oom;
+
+	dbus_message_unref(reply);
+
+	dbus_error_free(&error);
+
+	return DBUS_HANDLER_RESULT_HANDLED;
+
+oom:
+	if (reply)
+		dbus_message_unref(reply);
+
+	dbus_error_free(&error);
+
+	return DBUS_HANDLER_RESULT_NEED_MEMORY;
+}
+
+static DBusHandlerResult filter_handler(
+	DBusConnection *c,
+	DBusMessage *m,
+	void *userdata) {
+
+	rd_device *d;
+	DBusError error;
+	char *name_owner = NULL;
+
+	dbus_error_init(&error);
+
+	d = userdata;
+	assert(d->ref >= 1);
+
+	if (dbus_message_is_signal(m, "org.freedesktop.DBus", "NameLost")) {
+		const char *name;
+
+		if (!dbus_message_get_args(
+			    m,
+			    &error,
+			    DBUS_TYPE_STRING, &name,
+			    DBUS_TYPE_INVALID))
+			goto invalid;
+
+		if (strcmp(name, d->service_name) == 0 && d->owning) {
+			/* Verify the actual owner of the name to avoid leaked NameLost
+			 * signals from previous reservations. The D-Bus daemon will send
+			 * all messages asynchronously in the correct order, but we could
+			 * potentially process them too late due to the pseudo-blocking
+			 * call mechanism used during both acquisition and release. This
+			 * can happen if we release the device and immediately after
+			 * reacquire it before NameLost is processed. */
+			if (!d->gave_up) {
+				const char *un;
+
+				if ((un = dbus_bus_get_unique_name(c)) && rd_dbus_get_name_owner(c, d->service_name, &name_owner, &error) == 0)
+					if (strcmp(name_owner, un) == 0)
+						goto invalid; /* Name still owned by us */
+			}
+
+			d->owning = 0;
+
+			if (!d->gave_up)  {
+				d->ref++;
+
+				if (d->request_cb)
+					d->request_cb(d, 1);
+				d->gave_up = 1;
+
+				rd_release(d);
+			}
+
+		}
+	}
+
+invalid:
+	free(name_owner);
+	dbus_error_free(&error);
+
+	return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
+}
+
+
+static const struct DBusObjectPathVTable vtable ={
+	.message_function = object_handler
+};
+
+int rd_acquire(
+	rd_device **_d,
+	DBusConnection *connection,
+	const char *device_name,
+	const char *application_name,
+	int32_t priority,
+	rd_request_cb_t request_cb,
+	DBusError *error) {
+
+	rd_device *d = NULL;
+	int r, k;
+	DBusError _error;
+	DBusMessage *m = NULL, *reply = NULL;
+	dbus_bool_t good;
+
+	if (!error)
+		error = &_error;
+
+	dbus_error_init(error);
+
+	if (!_d)
+		return -EINVAL;
+
+	if (!connection)
+		return -EINVAL;
+
+	if (!device_name)
+		return -EINVAL;
+
+	if (!request_cb && priority != INT32_MAX)
+		return -EINVAL;
+
+	if (!(d = calloc(sizeof(rd_device), 1)))
+		return -ENOMEM;
+
+	d->ref = 1;
+
+	if (!(d->device_name = strdup(device_name))) {
+		r = -ENOMEM;
+		goto fail;
+	}
+
+	if (!(d->application_name = strdup(application_name))) {
+		r = -ENOMEM;
+		goto fail;
+	}
+
+	d->priority = priority;
+	d->connection = dbus_connection_ref(connection);
+	d->request_cb = request_cb;
+
+	if (!(d->service_name = malloc(sizeof(SERVICE_PREFIX) + strlen(device_name)))) {
+		r = -ENOMEM;
+		goto fail;
+	}
+	sprintf(d->service_name, SERVICE_PREFIX "%s", d->device_name);
+
+	if (!(d->object_path = malloc(sizeof(OBJECT_PREFIX) + strlen(device_name)))) {
+		r = -ENOMEM;
+		goto fail;
+	}
+	sprintf(d->object_path, OBJECT_PREFIX "%s", d->device_name);
+
+	if ((k = dbus_bus_request_name(
+		     d->connection,
+		     d->service_name,
+		     DBUS_NAME_FLAG_DO_NOT_QUEUE|
+		     (priority < INT32_MAX ? DBUS_NAME_FLAG_ALLOW_REPLACEMENT : 0),
+		     error)) < 0) {
+		r = -EIO;
+		goto fail;
+	}
+
+	if (k == DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER)
+		goto success;
+
+	if (k != DBUS_REQUEST_NAME_REPLY_EXISTS) {
+		r = -EIO;
+		goto fail;
+	}
+
+	if (priority <= INT32_MIN) {
+		r = -EBUSY;
+		goto fail;
+	}
+
+	if (!(m = dbus_message_new_method_call(
+		      d->service_name,
+		      d->object_path,
+		      "org.freedesktop.ReserveDevice1",
+		      "RequestRelease"))) {
+		r = -ENOMEM;
+		goto fail;
+	}
+
+	if (!dbus_message_append_args(
+		    m,
+		    DBUS_TYPE_INT32, &d->priority,
+		    DBUS_TYPE_INVALID)) {
+		r = -ENOMEM;
+		goto fail;
+	}
+
+	if (!(reply = dbus_connection_send_with_reply_and_block(
+		      d->connection,
+		      m,
+		      5000, /* 5s */
+		      error))) {
+
+		if (dbus_error_has_name(error, DBUS_ERROR_TIMED_OUT) ||
+		    dbus_error_has_name(error, DBUS_ERROR_UNKNOWN_METHOD) ||
+		    dbus_error_has_name(error, DBUS_ERROR_NO_REPLY)) {
+			/* This must be treated as denied. */
+			r = -EBUSY;
+			goto fail;
+		}
+
+		r = -EIO;
+		goto fail;
+	}
+
+        dbus_message_unref(m);
+        m = NULL;
+
+	if (!dbus_message_get_args(
+		    reply,
+		    error,
+		    DBUS_TYPE_BOOLEAN, &good,
+		    DBUS_TYPE_INVALID)) {
+		r = -EIO;
+		goto fail;
+	}
+
+        dbus_message_unref(reply);
+        reply = NULL;
+
+	if (!good) {
+		r = -EBUSY;
+		goto fail;
+	}
+
+	if ((k = dbus_bus_request_name(
+		     d->connection,
+		     d->service_name,
+		     DBUS_NAME_FLAG_DO_NOT_QUEUE|
+		     (priority < INT32_MAX ? DBUS_NAME_FLAG_ALLOW_REPLACEMENT : 0)|
+		     DBUS_NAME_FLAG_REPLACE_EXISTING,
+		     error)) < 0) {
+		r = -EIO;
+		goto fail;
+	}
+
+	if (k != DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER) {
+		r = -EIO;
+		goto fail;
+	}
+
+success:
+	d->owning = 1;
+
+	if (!(dbus_connection_register_object_path(
+		      d->connection,
+		      d->object_path,
+		      &vtable,
+		      d))) {
+		r = -ENOMEM;
+		goto fail;
+	}
+
+	d->registered = 1;
+
+	if (!dbus_connection_add_filter(
+		    d->connection,
+		    filter_handler,
+		    d,
+		    NULL)) {
+		r = -ENOMEM;
+		goto fail;
+	}
+
+	d->filtering = 1;
+
+	*_d = d;
+	return 0;
+
+fail:
+	if (m)
+		dbus_message_unref(m);
+
+	if (reply)
+		dbus_message_unref(reply);
+
+	if (&_error == error)
+		dbus_error_free(&_error);
+
+	if (d)
+		rd_release(d);
+
+	return r;
+}
+
+void rd_release(
+	rd_device *d) {
+
+	if (!d)
+		return;
+
+	assert(d->ref > 0);
+
+	if (--d->ref > 0)
+		return;
+
+
+	if (d->filtering)
+		dbus_connection_remove_filter(
+			d->connection,
+			filter_handler,
+			d);
+
+	if (d->registered)
+		dbus_connection_unregister_object_path(
+			d->connection,
+			d->object_path);
+
+	if (d->owning)
+		dbus_bus_release_name(
+			d->connection,
+			d->service_name,
+			NULL);
+
+	free(d->device_name);
+	free(d->application_name);
+	free(d->application_device_name);
+	free(d->service_name);
+	free(d->object_path);
+
+	if (d->connection)
+		dbus_connection_unref(d->connection);
+
+	free(d);
+}
+
+int rd_set_application_device_name(rd_device *d, const char *n) {
+	char *t;
+
+	if (!d)
+		return -EINVAL;
+
+	assert(d->ref > 0);
+
+	if (!(t = strdup(n)))
+		return -ENOMEM;
+
+	free(d->application_device_name);
+	d->application_device_name = t;
+	return 0;
+}
+
+void rd_set_userdata(rd_device *d, void *userdata) {
+
+	if (!d)
+		return;
+
+	assert(d->ref > 0);
+	d->userdata = userdata;
+}
+
+void* rd_get_userdata(rd_device *d) {
+
+	if (!d)
+		return NULL;
+
+	assert(d->ref > 0);
+
+	return d->userdata;
+}
+
+int rd_dbus_get_name_owner(
+	DBusConnection *connection,
+	const char *name,
+	char **name_owner,
+	DBusError *error) {
+
+	DBusMessage *msg, *reply;
+	int r;
+
+	*name_owner = NULL;
+
+	if (!(msg = dbus_message_new_method_call(DBUS_SERVICE_DBUS, DBUS_PATH_DBUS, DBUS_INTERFACE_DBUS, "GetNameOwner"))) {
+		r = -ENOMEM;
+		goto fail;
+	}
+
+	if (!dbus_message_append_args(msg, DBUS_TYPE_STRING, &name, DBUS_TYPE_INVALID)) {
+		r = -ENOMEM;
+		goto fail;
+	}
+
+	reply = dbus_connection_send_with_reply_and_block(connection, msg, DBUS_TIMEOUT_USE_DEFAULT, error);
+	dbus_message_unref(msg);
+	msg = NULL;
+
+	if (reply) {
+		if (!dbus_message_get_args(reply, error, DBUS_TYPE_STRING, name_owner, DBUS_TYPE_INVALID)) {
+			dbus_message_unref(reply);
+			r = -EIO;
+			goto fail;
+		}
+
+		*name_owner = strdup(*name_owner);
+		dbus_message_unref(reply);
+
+		if (!*name_owner) {
+			r = -ENOMEM;
+			goto fail;
+		}
+
+	} else if (dbus_error_has_name(error, "org.freedesktop.DBus.Error.NameHasNoOwner"))
+		dbus_error_free(error);
+	else {
+		r = -EIO;
+		goto fail;
+	}
+
+	return 0;
+
+fail:
+	if (msg)
+		dbus_message_unref(msg);
+
+	return r;
+}