From 742282b7e96560ecbade6c8a113adac2c3ee1e3a Mon Sep 17 00:00:00 2001 From: Robin Gareus Date: Thu, 5 Jun 2014 01:55:31 +0200 Subject: proper dbus device reservation --- libs/ardouralsautil/reserve.c | 681 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 681 insertions(+) create mode 100644 libs/ardouralsautil/reserve.c (limited to 'libs/ardouralsautil/reserve.c') diff --git a/libs/ardouralsautil/reserve.c b/libs/ardouralsautil/reserve.c new file mode 100644 index 0000000000..9076333f77 --- /dev/null +++ b/libs/ardouralsautil/reserve.c @@ -0,0 +1,681 @@ +/*-*- 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 +#include +#include +#include +#include +#include + +#include "ardouralsautil/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 + "" + " \n" + " " + " " + " " + " " + " " + " " + " " + " " + " " + " " + " " + " " + " " + " " + " " + " " + " " + " " + " " + " " + " " + ""; + +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 * const *) &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 * const *) &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; + } + + if (!dbus_message_get_args( + reply, + error, + DBUS_TYPE_BOOLEAN, &good, + DBUS_TYPE_INVALID)) { + r = -EIO; + goto fail; + } + + 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; +} -- cgit v1.2.3