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Systemd/src/libsystemd-bus/test-bus-chat.c
Lennart Poettering ebcf1f97de bus: rework message handlers to always take an error argument 
Message handler callbacks can be simplified drastically if the
dispatcher automatically replies to method calls if errors are returned.

Thus: add an sd_bus_error argument to all message handlers. When we
dispatch a message handler and it returns negative or a set sd_bus_error
we send this as message error back to the client. This means errors
returned by handlers by default are given back to clients instead of
rippling all the way up to the event loop, which is desirable to make
things robust.

As a side-effect we can now easily turn the SELinux checks into normal
function calls, since the method call dispatcher will generate the right
error replies automatically now.

Also, make sure we always pass the error structure to all property and
method handlers as last argument to follow the usual style of passing
variables for return values as last argument.
2013-11-21 21:12:36 +01:00

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/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2013 Lennart Poettering
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 <assert.h>
#include <stdlib.h>
#include <pthread.h>
#include <unistd.h>
#include <fcntl.h>
#include "log.h"
#include "util.h"
#include "macro.h"
#include "sd-bus.h"
#include "bus-message.h"
#include "bus-error.h"
#include "bus-match.h"
#include "bus-internal.h"
#include "bus-util.h"
static int match_callback(sd_bus *bus, sd_bus_message *m, void *userdata, sd_bus_error *ret_error) {
log_info("Match triggered! interface=%s member=%s", strna(sd_bus_message_get_interface(m)), strna(sd_bus_message_get_member(m)));
return 0;
}
static int object_callback(sd_bus *bus, sd_bus_message *m, void *userdata, sd_bus_error *ret_error) {
int r;
assert(bus);
if (sd_bus_message_is_method_error(m, NULL))
return 0;
if (sd_bus_message_is_method_call(m, "org.object.test", "Foobar")) {
log_info("Invoked Foobar() on %s", sd_bus_message_get_path(m));
r = sd_bus_reply_method_return(m, NULL);
if (r < 0) {
log_error("Failed to send reply: %s", strerror(-r));
return r;
}
return 1;
}
return 0;
}
static int server_init(sd_bus **_bus) {
sd_bus *bus = NULL;
sd_id128_t id;
int r;
const char *unique;
assert(_bus);
r = sd_bus_open_user(&bus);
if (r < 0) {
log_error("Failed to connect to user bus: %s", strerror(-r));
goto fail;
}
r = sd_bus_get_server_id(bus, &id);
if (r < 0) {
log_error("Failed to get server ID: %s", strerror(-r));
goto fail;
}
r = sd_bus_get_unique_name(bus, &unique);
if (r < 0) {
log_error("Failed to get unique name: %s", strerror(-r));
goto fail;
}
log_info("Peer ID is " SD_ID128_FORMAT_STR ".", SD_ID128_FORMAT_VAL(id));
log_info("Unique ID: %s", unique);
log_info("Can send file handles: %i", sd_bus_can_send(bus, 'h'));
r = sd_bus_request_name(bus, "org.freedesktop.systemd.test", 0);
if (r < 0) {
log_error("Failed to acquire name: %s", strerror(-r));
goto fail;
}
r = sd_bus_add_fallback(bus, "/foo/bar", object_callback, NULL);
if (r < 0) {
log_error("Failed to add object: %s", strerror(-r));
goto fail;
}
r = sd_bus_add_match(bus, "type='signal',interface='foo.bar',member='Notify'", match_callback, NULL);
if (r < 0) {
log_error("Failed to add match: %s", strerror(-r));
goto fail;
}
r = sd_bus_add_match(bus, "type='signal',interface='org.freedesktop.DBus',member='NameOwnerChanged'", match_callback, NULL);
if (r < 0) {
log_error("Failed to add match: %s", strerror(-r));
goto fail;
}
bus_match_dump(&bus->match_callbacks, 0);
*_bus = bus;
return 0;
fail:
if (bus)
sd_bus_unref(bus);
return r;
}
static int server(sd_bus *bus) {
int r;
bool client1_gone = false, client2_gone = false;
while (!client1_gone || !client2_gone) {
_cleanup_bus_message_unref_ sd_bus_message *m = NULL;
pid_t pid = 0;
const char *label = NULL;
r = sd_bus_process(bus, &m);
if (r < 0) {
log_error("Failed to process requests: %s", strerror(-r));
goto fail;
}
if (r == 0) {
r = sd_bus_wait(bus, (uint64_t) -1);
if (r < 0) {
log_error("Failed to wait: %s", strerror(-r));
goto fail;
}
continue;
}
if (!m)
continue;
sd_bus_message_get_pid(m, &pid);
sd_bus_message_get_selinux_context(m, &label);
log_info("Got message! member=%s pid=%lu label=%s",
strna(sd_bus_message_get_member(m)),
(unsigned long) pid,
strna(label));
/* bus_message_dump(m); */
/* sd_bus_message_rewind(m, true); */
if (sd_bus_message_is_method_call(m, "org.freedesktop.systemd.test", "LowerCase")) {
const char *hello;
_cleanup_free_ char *lowercase = NULL;
r = sd_bus_message_read(m, "s", &hello);
if (r < 0) {
log_error("Failed to get parameter: %s", strerror(-r));
goto fail;
}
lowercase = strdup(hello);
if (!lowercase) {
r = log_oom();
goto fail;
}
ascii_strlower(lowercase);
r = sd_bus_reply_method_return(m, "s", lowercase);
if (r < 0) {
log_error("Failed to send reply: %s", strerror(-r));
goto fail;
}
} else if (sd_bus_message_is_method_call(m, "org.freedesktop.systemd.test", "ExitClient1")) {
r = sd_bus_reply_method_return(m, NULL);
if (r < 0) {
log_error("Failed to send reply: %s", strerror(-r));
goto fail;
}
client1_gone = true;
} else if (sd_bus_message_is_method_call(m, "org.freedesktop.systemd.test", "ExitClient2")) {
r = sd_bus_reply_method_return(m, NULL);
if (r < 0) {
log_error("Failed to send reply: %s", strerror(-r));
goto fail;
}
client2_gone = true;
} else if (sd_bus_message_is_method_call(m, "org.freedesktop.systemd.test", "Slow")) {
sleep(1);
r = sd_bus_reply_method_return(m, NULL);
if (r < 0) {
log_error("Failed to send reply: %s", strerror(-r));
goto fail;
}
} else if (sd_bus_message_is_method_call(m, "org.freedesktop.systemd.test", "FileDescriptor")) {
int fd;
static const char x = 'X';
r = sd_bus_message_read(m, "h", &fd);
if (r < 0) {
log_error("Failed to get parameter: %s", strerror(-r));
goto fail;
}
log_info("Received fd=%d", fd);
if (write(fd, &x, 1) < 0) {
log_error("Failed to write to fd: %m");
close_nointr_nofail(fd);
goto fail;
}
r = sd_bus_reply_method_return(m, NULL);
if (r < 0) {
log_error("Failed to send reply: %s", strerror(-r));
goto fail;
}
} else if (sd_bus_message_is_method_call(m, NULL, NULL)) {
r = sd_bus_reply_method_error(
m,
&SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_UNKNOWN_METHOD, "Unknown method."));
if (r < 0) {
log_error("Failed to send reply: %s", strerror(-r));
goto fail;
}
}
}
r = 0;
fail:
if (bus) {
sd_bus_flush(bus);
sd_bus_unref(bus);
}
return r;
}
static void* client1(void*p) {
_cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
sd_bus *bus = NULL;
sd_bus_error error = SD_BUS_ERROR_NULL;
const char *hello;
int r;
int pp[2] = { -1, -1 };
char x;
r = sd_bus_open_user(&bus);
if (r < 0) {
log_error("Failed to connect to user bus: %s", strerror(-r));
goto finish;
}
r = sd_bus_call_method(
bus,
"org.freedesktop.systemd.test",
"/",
"org.freedesktop.systemd.test",
"LowerCase",
&error,
&reply,
"s",
"HELLO");
if (r < 0) {
log_error("Failed to issue method call: %s", strerror(-r));
goto finish;
}
r = sd_bus_message_read(reply, "s", &hello);
if (r < 0) {
log_error("Failed to get string: %s", strerror(-r));
goto finish;
}
assert(streq(hello, "hello"));
if (pipe2(pp, O_CLOEXEC|O_NONBLOCK) < 0) {
log_error("Failed to allocate pipe: %m");
r = -errno;
goto finish;
}
log_info("Sending fd=%d", pp[1]);
r = sd_bus_call_method(
bus,
"org.freedesktop.systemd.test",
"/",
"org.freedesktop.systemd.test",
"FileDescriptor",
&error,
NULL,
"h",
pp[1]);
if (r < 0) {
log_error("Failed to issue method call: %s", strerror(-r));
goto finish;
}
errno = 0;
if (read(pp[0], &x, 1) <= 0) {
log_error("Failed to read from pipe: %s", errno ? strerror(errno) : "early read");
goto finish;
}
r = 0;
finish:
if (bus) {
_cleanup_bus_message_unref_ sd_bus_message *q;
r = sd_bus_message_new_method_call(
bus,
"org.freedesktop.systemd.test",
"/",
"org.freedesktop.systemd.test",
"ExitClient1",
&q);
if (r < 0)
log_error("Failed to allocate method call: %s", strerror(-r));
else
sd_bus_send(bus, q, NULL);
sd_bus_flush(bus);
sd_bus_unref(bus);
}
sd_bus_error_free(&error);
close_pipe(pp);
return INT_TO_PTR(r);
}
static int quit_callback(sd_bus *b, sd_bus_message *m, void *userdata, sd_bus_error *ret_error) {
bool *x = userdata;
log_error("Quit callback: %s", strerror(sd_bus_message_get_errno(m)));
*x = 1;
return 1;
}
static void* client2(void*p) {
_cleanup_bus_message_unref_ sd_bus_message *m = NULL, *reply = NULL;
sd_bus *bus = NULL;
sd_bus_error error = SD_BUS_ERROR_NULL;
bool quit = false;
const char *mid;
int r;
r = sd_bus_open_user(&bus);
if (r < 0) {
log_error("Failed to connect to user bus: %s", strerror(-r));
goto finish;
}
r = sd_bus_message_new_method_call(
bus,
"org.freedesktop.systemd.test",
"/foo/bar/waldo/piep",
"org.object.test",
"Foobar",
&m);
if (r < 0) {
log_error("Failed to allocate method call: %s", strerror(-r));
goto finish;
}
r = sd_bus_send(bus, m, NULL);
if (r < 0) {
log_error("Failed to issue method call: %s", bus_error_message(&error, -r));
goto finish;
}
sd_bus_message_unref(m);
m = NULL;
r = sd_bus_message_new_signal(
bus,
"/foobar",
"foo.bar",
"Notify",
&m);
if (r < 0) {
log_error("Failed to allocate signal: %s", strerror(-r));
goto finish;
}
r = sd_bus_send(bus, m, NULL);
if (r < 0) {
log_error("Failed to issue signal: %s", bus_error_message(&error, -r));
goto finish;
}
sd_bus_message_unref(m);
m = NULL;
r = sd_bus_message_new_method_call(
bus,
"org.freedesktop.systemd.test",
"/",
"org.freedesktop.DBus.Peer",
"GetMachineId",
&m);
if (r < 0) {
log_error("Failed to allocate method call: %s", strerror(-r));
goto finish;
}
r = sd_bus_call(bus, m, 0, &error, &reply);
if (r < 0) {
log_error("Failed to issue method call: %s", bus_error_message(&error, -r));
goto finish;
}
r = sd_bus_message_read(reply, "s", &mid);
if (r < 0) {
log_error("Failed to parse machine ID: %s", strerror(-r));
goto finish;
}
log_info("Machine ID is %s.", mid);
sd_bus_message_unref(m);
m = NULL;
r = sd_bus_message_new_method_call(
bus,
"org.freedesktop.systemd.test",
"/",
"org.freedesktop.systemd.test",
"Slow",
&m);
if (r < 0) {
log_error("Failed to allocate method call: %s", strerror(-r));
goto finish;
}
sd_bus_message_unref(reply);
reply = NULL;
r = sd_bus_call(bus, m, 200 * USEC_PER_MSEC, &error, &reply);
if (r < 0)
log_info("Failed to issue method call: %s", bus_error_message(&error, -r));
else
log_info("Slow call succeed.");
sd_bus_message_unref(m);
m = NULL;
r = sd_bus_message_new_method_call(
bus,
"org.freedesktop.systemd.test",
"/",
"org.freedesktop.systemd.test",
"Slow",
&m);
if (r < 0) {
log_error("Failed to allocate method call: %s", strerror(-r));
goto finish;
}
r = sd_bus_call_async(bus, m, quit_callback, &quit, 200 * USEC_PER_MSEC, NULL);
if (r < 0) {
log_info("Failed to issue method call: %s", bus_error_message(&error, -r));
goto finish;
}
while (!quit) {
r = sd_bus_process(bus, NULL);
if (r < 0) {
log_error("Failed to process requests: %s", strerror(-r));
goto finish;
}
if (r == 0) {
r = sd_bus_wait(bus, (uint64_t) -1);
if (r < 0) {
log_error("Failed to wait: %s", strerror(-r));
goto finish;
}
}
}
r = 0;
finish:
if (bus) {
_cleanup_bus_message_unref_ sd_bus_message *q;
r = sd_bus_message_new_method_call(
bus,
"org.freedesktop.systemd.test",
"/",
"org.freedesktop.systemd.test",
"ExitClient2",
&q);
if (r < 0) {
log_error("Failed to allocate method call: %s", strerror(-r));
goto finish;
}
sd_bus_send(bus, q, NULL);
sd_bus_flush(bus);
sd_bus_unref(bus);
}
sd_bus_error_free(&error);
return INT_TO_PTR(r);
}
int main(int argc, char *argv[]) {
pthread_t c1, c2;
sd_bus *bus;
void *p;
int q, r;
r = server_init(&bus);
if (r < 0) {
log_info("Failed to connect to bus, skipping tests.");
return EXIT_TEST_SKIP;
}
log_info("Initialized...");
r = pthread_create(&c1, NULL, client1, bus);
if (r != 0)
return EXIT_FAILURE;
r = pthread_create(&c2, NULL, client2, bus);
if (r != 0)
return EXIT_FAILURE;
r = server(bus);
q = pthread_join(c1, &p);
if (q != 0)
return EXIT_FAILURE;
if (PTR_TO_INT(p) < 0)
return EXIT_FAILURE;
q = pthread_join(c2, &p);
if (q != 0)
return EXIT_FAILURE;
if (PTR_TO_INT(p) < 0)
return EXIT_FAILURE;
if (r < 0)
return EXIT_FAILURE;
return EXIT_SUCCESS;
}
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