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Systemd/src/dbus-common.c

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/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2010 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 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
General Public License for more details.
You should have received a copy of the GNU General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <assert.h>
#include <sys/socket.h>
#include <errno.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <dbus/dbus.h>
#include <string.h>
#include "log.h"
#include "dbus-common.h"
#include "util.h"
#include "def.h"
#include "strv.h"
int bus_check_peercred(DBusConnection *c) {
int fd;
struct ucred ucred;
socklen_t l;
assert(c);
assert_se(dbus_connection_get_unix_fd(c, &fd));
l = sizeof(struct ucred);
if (getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &ucred, &l) < 0) {
log_error("SO_PEERCRED failed: %m");
return -errno;
}
if (l != sizeof(struct ucred)) {
log_error("SO_PEERCRED returned wrong size.");
return -E2BIG;
}
if (ucred.uid != 0)
return -EPERM;
return 1;
}
static int sync_auth(DBusConnection *bus, DBusError *error) {
usec_t begin, tstamp;
assert(bus);
/* This complexity should probably move into D-Bus itself:
*
* https://bugs.freedesktop.org/show_bug.cgi?id=35189 */
begin = tstamp = now(CLOCK_MONOTONIC);
for (;;) {
if (tstamp > begin + DEFAULT_TIMEOUT_USEC)
break;
if (dbus_connection_get_is_authenticated(bus))
break;
if (!dbus_connection_read_write_dispatch(bus, ((begin + DEFAULT_TIMEOUT_USEC - tstamp) + USEC_PER_MSEC - 1) / USEC_PER_MSEC))
break;
tstamp = now(CLOCK_MONOTONIC);
}
if (!dbus_connection_get_is_connected(bus)) {
dbus_set_error_const(error, DBUS_ERROR_NO_SERVER, "Connection terminated during authentication.");
return -ECONNREFUSED;
}
if (!dbus_connection_get_is_authenticated(bus)) {
dbus_set_error_const(error, DBUS_ERROR_TIMEOUT, "Failed to authenticate in time.");
return -EACCES;
}
return 0;
}
int bus_connect(DBusBusType t, DBusConnection **_bus, bool *private, DBusError *error) {
DBusConnection *bus;
int r;
assert(_bus);
/* If we are root, then let's not go via the bus */
if (geteuid() == 0 && t == DBUS_BUS_SYSTEM) {
if (!(bus = dbus_connection_open_private("unix:path=/run/systemd/private", error))) {
#ifndef LEGACY
dbus_error_free(error);
/* Retry with the pre v21 socket name, to ease upgrades */
if (!(bus = dbus_connection_open_private("unix:abstract=/org/freedesktop/systemd1/private", error)))
#endif
return -EIO;
}
dbus_connection_set_exit_on_disconnect(bus, FALSE);
if (bus_check_peercred(bus) < 0) {
dbus_connection_close(bus);
dbus_connection_unref(bus);
dbus_set_error_const(error, DBUS_ERROR_ACCESS_DENIED, "Failed to verify owner of bus.");
return -EACCES;
}
if (private)
*private = true;
} else {
if (!(bus = dbus_bus_get_private(t, error)))
return -EIO;
dbus_connection_set_exit_on_disconnect(bus, FALSE);
if (private)
*private = false;
}
if ((r = sync_auth(bus, error)) < 0) {
dbus_connection_close(bus);
dbus_connection_unref(bus);
return r;
}
*_bus = bus;
return 0;
}
int bus_connect_system_ssh(const char *user, const char *host, DBusConnection **_bus, DBusError *error) {
DBusConnection *bus;
char *p = NULL;
int r;
assert(_bus);
assert(user || host);
if (user && host)
asprintf(&p, "exec:path=ssh,argv1=-xT,argv2=%s@%s,argv3=systemd-stdio-bridge", user, host);
else if (user)
asprintf(&p, "exec:path=ssh,argv1=-xT,argv2=%s@localhost,argv3=systemd-stdio-bridge", user);
else if (host)
asprintf(&p, "exec:path=ssh,argv1=-xT,argv2=%s,argv3=systemd-stdio-bridge", host);
if (!p) {
dbus_set_error_const(error, DBUS_ERROR_NO_MEMORY, NULL);
return -ENOMEM;
}
bus = dbus_connection_open_private(p, error);
free(p);
if (!bus)
return -EIO;
dbus_connection_set_exit_on_disconnect(bus, FALSE);
if ((r = sync_auth(bus, error)) < 0) {
dbus_connection_close(bus);
dbus_connection_unref(bus);
return r;
}
if (!dbus_bus_register(bus, error)) {
dbus_connection_close(bus);
dbus_connection_unref(bus);
return r;
}
*_bus = bus;
return 0;
}
int bus_connect_system_polkit(DBusConnection **_bus, DBusError *error) {
DBusConnection *bus;
int r;
assert(_bus);
/* Don't bother with PolicyKit if we are root */
if (geteuid() == 0)
return bus_connect(DBUS_BUS_SYSTEM, _bus, NULL, error);
if (!(bus = dbus_connection_open_private("exec:path=pkexec,argv1=" SYSTEMD_STDIO_BRIDGE_BINARY_PATH, error)))
return -EIO;
dbus_connection_set_exit_on_disconnect(bus, FALSE);
if ((r = sync_auth(bus, error)) < 0) {
dbus_connection_close(bus);
dbus_connection_unref(bus);
return r;
}
if (!dbus_bus_register(bus, error)) {
dbus_connection_close(bus);
dbus_connection_unref(bus);
return r;
}
*_bus = bus;
return 0;
}
const char *bus_error_message(const DBusError *error) {
assert(error);
/* Sometimes the D-Bus server is a little bit too verbose with
* its error messages, so let's override them here */
if (dbus_error_has_name(error, DBUS_ERROR_ACCESS_DENIED))
return "Access denied";
return error->message;
}
DBusHandlerResult bus_default_message_handler(
DBusConnection *c,
DBusMessage *message,
const char *introspection,
const char *interfaces,
const BusProperty *properties) {
DBusError error;
DBusMessage *reply = NULL;
int r;
assert(c);
assert(message);
dbus_error_init(&error);
if (dbus_message_is_method_call(message, "org.freedesktop.DBus.Introspectable", "Introspect") && introspection) {
if (!(reply = dbus_message_new_method_return(message)))
goto oom;
if (!dbus_message_append_args(reply, DBUS_TYPE_STRING, &introspection, DBUS_TYPE_INVALID))
goto oom;
} else if (dbus_message_is_method_call(message, "org.freedesktop.DBus.Properties", "Get") && properties) {
const char *interface, *property;
const BusProperty *p;
if (!dbus_message_get_args(
message,
&error,
DBUS_TYPE_STRING, &interface,
DBUS_TYPE_STRING, &property,
DBUS_TYPE_INVALID))
return bus_send_error_reply(c, message, &error, -EINVAL);
for (p = properties; p->property; p++)
if (streq(p->interface, interface) && streq(p->property, property))
break;
if (p->property) {
DBusMessageIter iter, sub;
if (!(reply = dbus_message_new_method_return(message)))
goto oom;
dbus_message_iter_init_append(reply, &iter);
if (!dbus_message_iter_open_container(&iter, DBUS_TYPE_VARIANT, p->signature, &sub))
goto oom;
if ((r = p->append(&sub, property, (void*) p->data)) < 0) {
if (r == -ENOMEM)
goto oom;
dbus_message_unref(reply);
return bus_send_error_reply(c, message, NULL, r);
}
if (!dbus_message_iter_close_container(&iter, &sub))
goto oom;
} else {
if (!nulstr_contains(interfaces, interface))
dbus_set_error_const(&error, DBUS_ERROR_UNKNOWN_INTERFACE, "Unknown interface");
else
dbus_set_error_const(&error, DBUS_ERROR_UNKNOWN_PROPERTY, "Unknown property");
return bus_send_error_reply(c, message, &error, -EINVAL);
}
} else if (dbus_message_is_method_call(message, "org.freedesktop.DBus.Properties", "GetAll") && properties) {
const char *interface;
const BusProperty *p;
DBusMessageIter iter, sub, sub2, sub3;
if (!dbus_message_get_args(
message,
&error,
DBUS_TYPE_STRING, &interface,
DBUS_TYPE_INVALID))
return bus_send_error_reply(c, message, &error, -EINVAL);
if (interface[0] && !nulstr_contains(interfaces, interface)) {
dbus_set_error_const(&error, DBUS_ERROR_UNKNOWN_INTERFACE, "Unknown interface");
return bus_send_error_reply(c, message, &error, -EINVAL);
}
if (!(reply = dbus_message_new_method_return(message)))
goto oom;
dbus_message_iter_init_append(reply, &iter);
if (!dbus_message_iter_open_container(&iter, DBUS_TYPE_ARRAY, "{sv}", &sub))
goto oom;
for (p = properties; p->property; p++) {
if (interface[0] && !streq(p->interface, interface))
continue;
if (!dbus_message_iter_open_container(&sub, DBUS_TYPE_DICT_ENTRY, NULL, &sub2) ||
!dbus_message_iter_append_basic(&sub2, DBUS_TYPE_STRING, &p->property) ||
!dbus_message_iter_open_container(&sub2, DBUS_TYPE_VARIANT, p->signature, &sub3))
goto oom;
if ((r = p->append(&sub3, p->property, (void*) p->data)) < 0) {
if (r == -ENOMEM)
goto oom;
dbus_message_unref(reply);
return bus_send_error_reply(c, message, NULL, r);
}
if (!dbus_message_iter_close_container(&sub2, &sub3) ||
!dbus_message_iter_close_container(&sub, &sub2))
goto oom;
}
if (!dbus_message_iter_close_container(&iter, &sub))
goto oom;
} else if (dbus_message_is_method_call(message, "org.freedesktop.DBus.Properties", "Set") && properties) {
const char *interface, *property;
DBusMessageIter iter;
const BusProperty *p;
if (!dbus_message_iter_init(message, &iter) ||
dbus_message_iter_get_arg_type(&iter) != DBUS_TYPE_STRING)
return bus_send_error_reply(c, message, NULL, -EINVAL);
dbus_message_iter_get_basic(&iter, &interface);
if (!dbus_message_iter_next(&iter) ||
dbus_message_iter_get_arg_type(&iter) != DBUS_TYPE_STRING)
return bus_send_error_reply(c, message, NULL, -EINVAL);
dbus_message_iter_get_basic(&iter, &property);
if (!dbus_message_iter_next(&iter) ||
dbus_message_iter_get_arg_type(&iter) != DBUS_TYPE_VARIANT ||
dbus_message_iter_has_next(&iter))
return bus_send_error_reply(c, message, NULL, -EINVAL);
for (p = properties; p->property; p++)
if (streq(p->interface, interface) && streq(p->property, property))
break;
if (p->set) {
DBusMessageIter sub;
char *sig;
dbus_message_iter_recurse(&iter, &sub);
if (!(sig = dbus_message_iter_get_signature(&sub)))
goto oom;
if (!streq(sig, p->signature)) {
dbus_free(sig);
return bus_send_error_reply(c, message, NULL, -EINVAL);
}
dbus_free(sig);
if ((r = p->set(&sub, property)) < 0) {
if (r == -ENOMEM)
goto oom;
return bus_send_error_reply(c, message, NULL, r);
}
if (!(reply = dbus_message_new_method_return(message)))
goto oom;
} else {
if (p->property)
dbus_set_error_const(&error, DBUS_ERROR_PROPERTY_READ_ONLY, "Property read-only");
else if (!nulstr_contains(interfaces, interface))
dbus_set_error_const(&error, DBUS_ERROR_UNKNOWN_INTERFACE, "Unknown interface");
else
dbus_set_error_const(&error, DBUS_ERROR_UNKNOWN_PROPERTY, "Unknown property");
return bus_send_error_reply(c, message, &error, -EINVAL);
}
} else if (!nulstr_contains(interfaces, dbus_message_get_interface(message))) {
dbus_set_error_const(&error, DBUS_ERROR_UNKNOWN_INTERFACE, "Unknown interface");
return bus_send_error_reply(c, message, &error, -EINVAL);
}
if (reply) {
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;
oom:
if (reply)
dbus_message_unref(reply);
dbus_error_free(&error);
return DBUS_HANDLER_RESULT_NEED_MEMORY;
}
int bus_property_append_string(DBusMessageIter *i, const char *property, void *data) {
const char *t = data;
assert(i);
assert(property);
if (!t)
t = "";
if (!dbus_message_iter_append_basic(i, DBUS_TYPE_STRING, &t))
return -ENOMEM;
return 0;
}
int bus_property_append_strv(DBusMessageIter *i, const char *property, void *data) {
DBusMessageIter sub;
char **t = data;
assert(i);
assert(property);
if (!dbus_message_iter_open_container(i, DBUS_TYPE_ARRAY, "s", &sub))
return -ENOMEM;
STRV_FOREACH(t, t)
if (!dbus_message_iter_append_basic(&sub, DBUS_TYPE_STRING, t))
return -ENOMEM;
if (!dbus_message_iter_close_container(i, &sub))
return -ENOMEM;
return 0;
}
int bus_property_append_bool(DBusMessageIter *i, const char *property, void *data) {
bool *b = data;
dbus_bool_t db;
assert(i);
assert(property);
assert(b);
db = *b;
if (!dbus_message_iter_append_basic(i, DBUS_TYPE_BOOLEAN, &db))
return -ENOMEM;
return 0;
}
int bus_property_append_uint64(DBusMessageIter *i, const char *property, void *data) {
assert(i);
assert(property);
assert(data);
/* Let's ensure that pid_t is actually 64bit, and hence this
* function can be used for usec_t */
assert_cc(sizeof(uint64_t) == sizeof(usec_t));
if (!dbus_message_iter_append_basic(i, DBUS_TYPE_UINT64, data))
return -ENOMEM;
return 0;
}
int bus_property_append_uint32(DBusMessageIter *i, const char *property, void *data) {
assert(i);
assert(property);
assert(data);
/* Let's ensure that pid_t and mode_t is actually 32bit, and
* hence this function can be used for pid_t/mode_t */
assert_cc(sizeof(uint32_t) == sizeof(pid_t));
assert_cc(sizeof(uint32_t) == sizeof(mode_t));
assert_cc(sizeof(uint32_t) == sizeof(unsigned));
if (!dbus_message_iter_append_basic(i, DBUS_TYPE_UINT32, data))
return -ENOMEM;
return 0;
}
int bus_property_append_int32(DBusMessageIter *i, const char *property, void *data) {
assert(i);
assert(property);
assert(data);
assert_cc(sizeof(int32_t) == sizeof(int));
if (!dbus_message_iter_append_basic(i, DBUS_TYPE_INT32, data))
return -ENOMEM;
return 0;
}
int bus_property_append_size(DBusMessageIter *i, const char *property, void *data) {
uint64_t u;
assert(i);
assert(property);
assert(data);
u = (uint64_t) *(size_t*) data;
if (!dbus_message_iter_append_basic(i, DBUS_TYPE_UINT64, &u))
return -ENOMEM;
return 0;
}
int bus_property_append_ul(DBusMessageIter *i, const char *property, void *data) {
uint64_t u;
assert(i);
assert(property);
assert(data);
u = (uint64_t) *(unsigned long*) data;
if (!dbus_message_iter_append_basic(i, DBUS_TYPE_UINT64, &u))
return -ENOMEM;
return 0;
}
int bus_property_append_long(DBusMessageIter *i, const char *property, void *data) {
uint64_t u;
assert(i);
assert(property);
assert(data);
u = (int64_t) *(long*) data;
if (!dbus_message_iter_append_basic(i, DBUS_TYPE_INT64, &u))
return -ENOMEM;
return 0;
}
const char *bus_errno_to_dbus(int error) {
switch(error) {
case -EINVAL:
return DBUS_ERROR_INVALID_ARGS;
case -ENOMEM:
return DBUS_ERROR_NO_MEMORY;
case -EPERM:
case -EACCES:
return DBUS_ERROR_ACCESS_DENIED;
case -ESRCH:
return DBUS_ERROR_UNIX_PROCESS_ID_UNKNOWN;
case -ENOENT:
return DBUS_ERROR_FILE_NOT_FOUND;
case -EEXIST:
return DBUS_ERROR_FILE_EXISTS;
case -ETIMEDOUT:
case -ETIME:
return DBUS_ERROR_TIMEOUT;
case -EIO:
return DBUS_ERROR_IO_ERROR;
case -ENETRESET:
case -ECONNABORTED:
case -ECONNRESET:
return DBUS_ERROR_DISCONNECTED;
}
return DBUS_ERROR_FAILED;
}
DBusHandlerResult bus_send_error_reply(DBusConnection *c, DBusMessage *message, DBusError *berror, int error) {
DBusMessage *reply = NULL;
const char *name, *text;
if (berror && dbus_error_is_set(berror)) {
name = berror->name;
text = berror->message;
} else {
name = bus_errno_to_dbus(error);
text = strerror(-error);
}
if (!(reply = dbus_message_new_error(message, name, text)))
goto oom;
if (!dbus_connection_send(c, reply, NULL))
goto oom;
dbus_message_unref(reply);
if (berror)
dbus_error_free(berror);
return DBUS_HANDLER_RESULT_HANDLED;
oom:
if (reply)
dbus_message_unref(reply);
if (berror)
dbus_error_free(berror);
return DBUS_HANDLER_RESULT_NEED_MEMORY;
}
DBusMessage* bus_properties_changed_new(const char *path, const char *interface, const char *properties) {
DBusMessage *m;
DBusMessageIter iter, sub;
const char *i;
assert(interface);
assert(properties);
if (!(m = dbus_message_new_signal(path, "org.freedesktop.DBus.Properties", "PropertiesChanged")))
goto oom;
dbus_message_iter_init_append(m, &iter);
/* We won't send any property values, since they might be
* large and sometimes not cheap to generated */
if (!dbus_message_iter_append_basic(&iter, DBUS_TYPE_STRING, &interface) ||
!dbus_message_iter_open_container(&iter, DBUS_TYPE_ARRAY, "{sv}", &sub) ||
!dbus_message_iter_close_container(&iter, &sub) ||
!dbus_message_iter_open_container(&iter, DBUS_TYPE_ARRAY, "s", &sub))
goto oom;
NULSTR_FOREACH(i, properties)
if (!dbus_message_iter_append_basic(&sub, DBUS_TYPE_STRING, &i))
goto oom;
if (!dbus_message_iter_close_container(&iter, &sub))
goto oom;
return m;
oom:
if (m)
dbus_message_unref(m);
return NULL;
}
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