Systemd/src/bus-proxyd/proxy.h

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#pragma once
/***
This file is part of systemd.
Copyright 2014 David Herrmann
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/>.
***/
#include "sd-bus.h"
#include "bus-xml-policy.h"
typedef struct Proxy Proxy;
bus-proxy: make StartServiceByName synchronous The StartServiceByName() call was provided by dbus-daemon to activate a service without sending a message. On receiption, dbus-daemon schedules an activation request (different modes are supported) and sends back the reply once activation is done. With kdbus, we marked StartServiceByName() as deprecated. There is no real reason to start services explicitly. Instead, applications should just *use* the service and rely on it being activated implicitly. However, we provide compatibility with dbus-daemon and implement StartServiceByName() on the proxy via a call to org.freedesktop.DBus.Peer.Ping() on the destination. This will activate the peer implicitly as part of the no-op Ping() method call (regardless whether the peer actually implements that call). Now, the problem is, StartServiceByName() was synchronous on dbus-daemon but isn't on bus-proxy. Hence, on return, there is no guarantee that ListNames includes the activated name. As this is required by some applications, we need to make this synchronous. This patch makes the proxy track the Ping() method call and send the reply of StartServiceByName() only once Ping() returned. We do not look at possible errors of Ping(), as there is no strict requirement for the peer to implement org.freedesktop.DBus.Peer. Furthermore, any interesting error should have already been caught by sd_bus_send() before. Note: This race was triggered by gdbus. The gdbus-proxy implementation relies on a name to be available after StartServiceByName() returns. This is highly fragile and should be dropped by gdbus. Even if the call is synchronous, there is no reason whatsoever to assume the service did not exit-on-idle before ListNames() returns. However, this race is much less likely than the startup race, so we try to be compatible to dbus-daemon now.
2015-07-31 13:25:04 +02:00
typedef struct ProxyActivation ProxyActivation;
#define PROXY_ACTIVATIONS_MAX (16) /* max parallel activation requests */
struct Proxy {
sd_bus *local_bus;
struct ucred local_creds;
int local_in;
int local_out;
sd_bus *destination_bus;
Set *owned_names;
SharedPolicy *policy;
bus-proxy: make StartServiceByName synchronous The StartServiceByName() call was provided by dbus-daemon to activate a service without sending a message. On receiption, dbus-daemon schedules an activation request (different modes are supported) and sends back the reply once activation is done. With kdbus, we marked StartServiceByName() as deprecated. There is no real reason to start services explicitly. Instead, applications should just *use* the service and rely on it being activated implicitly. However, we provide compatibility with dbus-daemon and implement StartServiceByName() on the proxy via a call to org.freedesktop.DBus.Peer.Ping() on the destination. This will activate the peer implicitly as part of the no-op Ping() method call (regardless whether the peer actually implements that call). Now, the problem is, StartServiceByName() was synchronous on dbus-daemon but isn't on bus-proxy. Hence, on return, there is no guarantee that ListNames includes the activated name. As this is required by some applications, we need to make this synchronous. This patch makes the proxy track the Ping() method call and send the reply of StartServiceByName() only once Ping() returned. We do not look at possible errors of Ping(), as there is no strict requirement for the peer to implement org.freedesktop.DBus.Peer. Furthermore, any interesting error should have already been caught by sd_bus_send() before. Note: This race was triggered by gdbus. The gdbus-proxy implementation relies on a name to be available after StartServiceByName() returns. This is highly fragile and should be dropped by gdbus. Even if the call is synchronous, there is no reason whatsoever to assume the service did not exit-on-idle before ListNames() returns. However, this race is much less likely than the startup race, so we try to be compatible to dbus-daemon now.
2015-07-31 13:25:04 +02:00
LIST_HEAD(ProxyActivation, activations);
size_t n_activations;
bool got_hello : 1;
bool queue_overflow : 1;
bool message_matched : 1;
bool synthetic_matched : 1;
};
bus-proxy: make StartServiceByName synchronous The StartServiceByName() call was provided by dbus-daemon to activate a service without sending a message. On receiption, dbus-daemon schedules an activation request (different modes are supported) and sends back the reply once activation is done. With kdbus, we marked StartServiceByName() as deprecated. There is no real reason to start services explicitly. Instead, applications should just *use* the service and rely on it being activated implicitly. However, we provide compatibility with dbus-daemon and implement StartServiceByName() on the proxy via a call to org.freedesktop.DBus.Peer.Ping() on the destination. This will activate the peer implicitly as part of the no-op Ping() method call (regardless whether the peer actually implements that call). Now, the problem is, StartServiceByName() was synchronous on dbus-daemon but isn't on bus-proxy. Hence, on return, there is no guarantee that ListNames includes the activated name. As this is required by some applications, we need to make this synchronous. This patch makes the proxy track the Ping() method call and send the reply of StartServiceByName() only once Ping() returned. We do not look at possible errors of Ping(), as there is no strict requirement for the peer to implement org.freedesktop.DBus.Peer. Furthermore, any interesting error should have already been caught by sd_bus_send() before. Note: This race was triggered by gdbus. The gdbus-proxy implementation relies on a name to be available after StartServiceByName() returns. This is highly fragile and should be dropped by gdbus. Even if the call is synchronous, there is no reason whatsoever to assume the service did not exit-on-idle before ListNames() returns. However, this race is much less likely than the startup race, so we try to be compatible to dbus-daemon now.
2015-07-31 13:25:04 +02:00
struct ProxyActivation {
LIST_FIELDS(ProxyActivation, activations_by_proxy);
Proxy *proxy;
sd_bus_message *request;
sd_bus_slot *slot;
};
int proxy_new(Proxy **out, int in_fd, int out_fd, const char *dest);
Proxy *proxy_free(Proxy *p);
int proxy_set_policy(Proxy *p, SharedPolicy *policy, char **configuration);
int proxy_hello_policy(Proxy *p, uid_t original_uid);
int proxy_match(sd_bus_message *m, void *userdata, sd_bus_error *error);
int proxy_run(Proxy *p);
DEFINE_TRIVIAL_CLEANUP_FUNC(Proxy*, proxy_free);