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systemd/src/bus-proxyd/bus-proxyd.c
Kay Sievers 1b09f548c7 turn kdbus support into a runtime option
./configure --enable/disable-kdbus can be used to set the default
behavior regarding kdbus.

If no kdbus kernel support is available, dbus-dameon will be used.

With --enable-kdbus, the kernel command line option "kdbus=0" can
be used to disable kdbus.

With --disable-kdbus, the kernel command line option "kdbus=1" is
required to enable kdbus support.
2015-06-17 18:01:49 +02:00

330 lines
9.2 KiB
C

/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2010 Lennart Poettering
Copyright 2013 Daniel Mack
Copyright 2014 Kay Sievers
Copyright 2015 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 <sys/socket.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <sys/prctl.h>
#include <stddef.h>
#include <getopt.h>
#include <pthread.h>
#include "log.h"
#include "util.h"
#include "sd-daemon.h"
#include "bus-internal.h"
#include "build.h"
#include "strv.h"
#include "def.h"
#include "capability.h"
#include "bus-xml-policy.h"
#include "proxy.h"
#include "formats-util.h"
static char *arg_address = NULL;
static char **arg_configuration = NULL;
typedef struct {
int fd;
SharedPolicy *policy;
uid_t bus_uid;
} ClientContext;
static ClientContext *client_context_free(ClientContext *c) {
if (!c)
return NULL;
safe_close(c->fd);
free(c);
return NULL;
}
DEFINE_TRIVIAL_CLEANUP_FUNC(ClientContext*, client_context_free);
static int client_context_new(ClientContext **out) {
_cleanup_(client_context_freep) ClientContext *c = NULL;
c = new0(ClientContext, 1);
if (!c)
return -ENOMEM;
c->fd = -1;
*out = c;
c = NULL;
return 0;
}
static void *run_client(void *userdata) {
_cleanup_(client_context_freep) ClientContext *c = userdata;
_cleanup_(proxy_freep) Proxy *p = NULL;
char comm[16];
int r;
r = proxy_new(&p, c->fd, c->fd, arg_address);
if (r < 0)
goto exit;
c->fd = -1;
/* set comm to "p$PIDu$UID" and suffix with '*' if truncated */
r = snprintf(comm, sizeof(comm), "p" PID_FMT "u" UID_FMT, p->local_creds.pid, p->local_creds.uid);
if (r >= (ssize_t)sizeof(comm))
comm[sizeof(comm) - 2] = '*';
(void) prctl(PR_SET_NAME, comm);
r = proxy_set_policy(p, c->policy, arg_configuration);
if (r < 0)
goto exit;
r = proxy_hello_policy(p, c->bus_uid);
if (r < 0)
goto exit;
r = proxy_run(p);
exit:
return NULL;
}
static int loop_clients(int accept_fd, uid_t bus_uid) {
_cleanup_(shared_policy_freep) SharedPolicy *sp = NULL;
pthread_attr_t attr;
int r;
r = pthread_attr_init(&attr);
if (r < 0) {
return log_error_errno(errno, "Cannot initialize pthread attributes: %m");
}
r = pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
if (r < 0) {
r = log_error_errno(errno, "Cannot mark pthread attributes as detached: %m");
goto finish;
}
r = shared_policy_new(&sp);
if (r < 0)
goto finish;
for (;;) {
ClientContext *c;
pthread_t tid;
int fd;
fd = accept4(accept_fd, NULL, NULL, SOCK_NONBLOCK | SOCK_CLOEXEC);
if (fd < 0) {
if (errno == EAGAIN || errno == EINTR)
continue;
r = log_error_errno(errno, "accept4() failed: %m");
goto finish;
}
r = client_context_new(&c);
if (r < 0) {
log_oom();
close(fd);
continue;
}
c->fd = fd;
c->policy = sp;
c->bus_uid = bus_uid;
r = pthread_create(&tid, &attr, run_client, c);
if (r < 0) {
log_error("Cannot spawn thread: %m");
client_context_free(c);
continue;
}
}
finish:
pthread_attr_destroy(&attr);
return r;
}
static int help(void) {
printf("%s [OPTIONS...]\n\n"
"DBus proxy server.\n\n"
" -h --help Show this help\n"
" --version Show package version\n"
" --configuration=PATH Configuration file or directory\n"
" --machine=MACHINE Connect to specified machine\n"
" --address=ADDRESS Connect to the bus specified by ADDRESS\n"
" (default: " DEFAULT_SYSTEM_BUS_ADDRESS ")\n",
program_invocation_short_name);
return 0;
}
static int parse_argv(int argc, char *argv[]) {
enum {
ARG_VERSION = 0x100,
ARG_ADDRESS,
ARG_CONFIGURATION,
ARG_MACHINE,
};
static const struct option options[] = {
{ "help", no_argument, NULL, 'h' },
{ "version", no_argument, NULL, ARG_VERSION },
{ "address", required_argument, NULL, ARG_ADDRESS },
{ "configuration", required_argument, NULL, ARG_CONFIGURATION },
{ "machine", required_argument, NULL, ARG_MACHINE },
{},
};
int c, r;
assert(argc >= 0);
assert(argv);
while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0)
switch (c) {
case 'h':
help();
return 0;
case ARG_VERSION:
puts(PACKAGE_STRING);
puts(SYSTEMD_FEATURES);
return 0;
case ARG_ADDRESS:
r = free_and_strdup(&arg_address, optarg);
if (r < 0)
return log_oom();
break;
case ARG_CONFIGURATION:
r = strv_extend(&arg_configuration, optarg);
if (r < 0)
return log_oom();
break;
case ARG_MACHINE: {
_cleanup_free_ char *e = NULL;
char *a;
e = bus_address_escape(optarg);
if (!e)
return log_oom();
a = strjoin("x-machine-kernel:machine=", e, ";x-machine-unix:machine=", e, NULL);
if (!a)
return log_oom();
free(arg_address);
arg_address = a;
break;
}
case '?':
return -EINVAL;
default:
assert_not_reached("Unhandled option");
}
if (argc > optind) {
log_error("Too many arguments");
return -EINVAL;
}
if (!arg_address) {
arg_address = strdup(DEFAULT_SYSTEM_BUS_ADDRESS);
if (!arg_address)
return log_oom();
}
return 1;
}
int main(int argc, char *argv[]) {
int r, accept_fd;
uid_t uid, bus_uid;
gid_t gid;
log_set_target(LOG_TARGET_JOURNAL_OR_KMSG);
log_parse_environment();
log_open();
bus_uid = getuid();
if (geteuid() == 0) {
const char *user = "systemd-bus-proxy";
r = get_user_creds(&user, &uid, &gid, NULL, NULL);
if (r < 0) {
log_error_errno(r, "Cannot resolve user name %s: %m", user);
goto finish;
}
r = drop_privileges(uid, gid, 1ULL << CAP_IPC_OWNER);
if (r < 0) {
log_error_errno(r, "Cannot drop privileges: %m");
goto finish;
}
}
r = parse_argv(argc, argv);
if (r <= 0)
goto finish;
r = sd_listen_fds(0);
if (r != 1) {
log_error("Illegal number of file descriptors passed");
goto finish;
}
accept_fd = SD_LISTEN_FDS_START;
r = fd_nonblock(accept_fd, false);
if (r < 0) {
log_error_errno(r, "Cannot mark accept-fd non-blocking: %m");
goto finish;
}
r = loop_clients(accept_fd, bus_uid);
finish:
sd_notify(false,
"STOPPING=1\n"
"STATUS=Shutting down.");
strv_free(arg_configuration);
free(arg_address);
return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
}