/*
SSSD
Service monitor - D-BUS features
Copyright (C) Stephen Gallagher 2008
This program 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 3 of the License, or
(at your option) any later version.
This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <sys/time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <tevent.h>
#include <dbus/dbus.h>
#include <limits.h>
#include "util/util.h"
#include "sbus/sssd_dbus.h"
#include "sbus/sssd_dbus_private.h"
static int sbus_server_destructor(void *ctx);
struct new_connection_data {
struct sbus_connection *server;
void *client_destructor_data;
};
/*
* new_connection_callback
* Actions to be run upon each new client connection
* Must either perform dbus_connection_ref() on the
* new connection or else close the connection with
* dbus_connection_close()
*/
static void sbus_server_init_new_connection(DBusServer *dbus_server,
DBusConnection *dbus_conn,
void *data)
{
struct new_connection_data *ncd;
struct sbus_connection *conn;
int ret;
DEBUG(SSSDBG_FUNC_DATA,"Entering.\n");
ncd = talloc_get_type(data, struct new_connection_data);
if (!ncd) {
return;
}
DEBUG(SSSDBG_FUNC_DATA,"Adding connection %p.\n", dbus_conn);
ret = sbus_init_connection(ncd->server, ncd->server->ev, dbus_conn,
SBUS_CONN_TYPE_PRIVATE, NULL,
ncd->client_destructor_data, &conn);
if (ret != 0) {
dbus_connection_close(dbus_conn);
DEBUG(SSSDBG_FUNC_DATA, "Closing connection (failed setup)\n");
return;
}
dbus_connection_ref(dbus_conn);
DEBUG(SSSDBG_FUNC_DATA,"Got a connection\n");
/*
* Initialize connection-specific features
* This function (or its callbacks) should also
* set up connection-specific methods.
*/
ret = ncd->server->srv_init_fn(conn, ncd->server->srv_init_data);
if (ret != EOK) {
DEBUG(SSSDBG_CRIT_FAILURE,"Initialization failed!\n");
dbus_connection_close(dbus_conn);
talloc_zfree(conn);
}
}
const char *
get_socket_address(TALLOC_CTX *mem_ctx, const char *address, bool use_symlink)
{
if (!use_symlink) {
return talloc_strdup(mem_ctx, address);
}
return talloc_asprintf(mem_ctx,
"%s.%lu", address, (unsigned long) getpid());
}
static errno_t
create_socket_symlink(const char *filename, const char *symlink_filename)
{
errno_t ret;
DEBUG(SSSDBG_TRACE_LIBS, "Symlinking the dbus path %s to a link %s\n",
filename, symlink_filename);
errno = 0;
ret = symlink(filename, symlink_filename);
if (ret != 0 && errno == EEXIST) {
/* Perhaps cruft after a previous server? */
errno = 0;
ret = unlink(symlink_filename);
if (ret != 0) {
ret = errno;
DEBUG(SSSDBG_CRIT_FAILURE,
"Cannot remove old symlink '%s': [%d][%s].\n",
symlink_filename, ret, strerror(ret));
return EIO;
}
errno = 0;
ret = symlink(filename, symlink_filename);
}
if (ret != 0) {
ret = errno;
DEBUG(SSSDBG_CRIT_FAILURE, "symlink() failed on file '%s': [%d][%s].\n",
filename, ret, strerror(ret));
return EIO;
}
return EOK;
}
static errno_t
remove_socket_symlink(const char *symlink_name)
{
errno_t ret;
char target[PATH_MAX];
char pidpath[PATH_MAX];
ssize_t numread = 0;
errno = 0;
numread = readlink(symlink_name, target, PATH_MAX-1);
if (numread < 0) {
ret = errno;
DEBUG(SSSDBG_OP_FAILURE,
"readlink failed [%d]: %s\n", ret, strerror(ret));
return ret;
}
target[numread] = '\0';
DEBUG(SSSDBG_TRACE_ALL, "The symlink points to [%s]\n", target);
/* We can only remove the symlink if it points to a socket with
* the same PID */
ret = snprintf(pidpath, PATH_MAX, "%s.%lu",
symlink_name, (unsigned long) getpid());
if (ret < 0) {
DEBUG(SSSDBG_OP_FAILURE, "snprintf failed\n");
return EIO;
} else if (ret >= PATH_MAX) {
DEBUG(SSSDBG_OP_FAILURE, "path too long?!?!\n");
return EIO;
}
DEBUG(SSSDBG_TRACE_ALL, "The path including our pid is [%s]\n", pidpath);
if (strcmp(pidpath, target) != 0) {
DEBUG(SSSDBG_CONF_SETTINGS,
"Will not remove symlink, seems to be owned by "
"another process\n");
return EOK;
}
ret = unlink(symlink_name);
if (ret != 0) {
ret = errno;
DEBUG(SSSDBG_CRIT_FAILURE,
"unlink failed to remove [%s] [%d]: %s\n",
symlink_name, ret, strerror(ret));
return ret;
}
DEBUG(SSSDBG_TRACE_ALL, "Removed the symlink\n");
return EOK;
}
/*
* dbus_new_server
* Set up a D-BUS server, integrate with the event loop
* for handling file descriptor and timed events
*/
int sbus_new_server(TALLOC_CTX *mem_ctx,
struct tevent_context *ev,
const char *address,
uid_t uid, gid_t gid,
bool use_symlink,
struct sbus_connection **_server,
sbus_server_conn_init_fn init_fn,
void *init_pvt_data,
void *client_destructor_data)
{
struct sbus_connection *server;
DBusServer *dbus_server;
DBusError dbus_error;
dbus_bool_t dbret;
char *tmp;
int ret, tmp_ret;
char *filename;
char *symlink_filename = NULL;
const char *socket_address;
struct stat stat_buf;
TALLOC_CTX *tmp_ctx;
struct new_connection_data *ncd;
*_server = NULL;
tmp_ctx = talloc_new(NULL);
if (!tmp_ctx) return ENOMEM;
socket_address = get_socket_address(tmp_ctx, address, use_symlink);
if (!socket_address) {
ret = ENOMEM;
goto done;
}
/* Set up D-BUS server */
dbus_error_init(&dbus_error);
dbus_server = dbus_server_listen(socket_address, &dbus_error);
if (!dbus_server) {
DEBUG(SSSDBG_CRIT_FAILURE,
"dbus_server_listen failed! (name=%s, message=%s)\n",
dbus_error.name, dbus_error.message);
if (dbus_error_is_set(&dbus_error)) dbus_error_free(&dbus_error);
ret = EIO;
goto done;
}
filename = strchr(socket_address, '/');
if (filename == NULL) {
DEBUG(SSSDBG_CRIT_FAILURE,
"Unexpected dbus address [%s].\n", socket_address);
ret = EIO;
goto done;
}
if (use_symlink) {
symlink_filename = strchr(address, '/');
if (symlink_filename == NULL) {
DEBUG(SSSDBG_CRIT_FAILURE,
"Unexpected dbus address [%s].\n", address);
ret = EIO;
goto done;
}
ret = create_socket_symlink(filename, symlink_filename);
if (ret != EOK) {
DEBUG(SSSDBG_CRIT_FAILURE, "Could not create symlink [%d]: %s\n",
ret, strerror(ret));
ret = EIO;
goto done;
}
}
/* Both check_file and chmod can handle both the symlink and
* the socket */
ret = check_file(filename,
getuid(), getgid(), S_IFSOCK, S_IFMT, &stat_buf, true);
if (ret != EOK) {
DEBUG(SSSDBG_CRIT_FAILURE, "check_file failed for [%s].\n", filename);
ret = EIO;
goto done;
}
if ((stat_buf.st_mode & ~S_IFMT) != (S_IRUSR|S_IWUSR)) {
ret = chmod(filename, (S_IRUSR|S_IWUSR));
if (ret != EOK) {
ret = errno;
DEBUG(SSSDBG_CRIT_FAILURE,
"chmod failed for [%s]: [%d][%s].\n", filename, ret,
sss_strerror(ret));
ret = EIO;
goto done;
}
}
if (stat_buf.st_uid != uid || stat_buf.st_gid != gid) {
ret = chown(filename, uid, gid);
if (ret != EOK) {
ret = errno;
DEBUG(SSSDBG_CRIT_FAILURE,
"chown failed for [%s]: [%d][%s].\n", filename, ret,
sss_strerror(ret));
ret = EIO;
goto done;
}
}
tmp = dbus_server_get_address(dbus_server);
DEBUG(SSSDBG_TRACE_FUNC, "D-BUS Server listening on %s\n", tmp);
free(tmp);
server = talloc_zero(tmp_ctx, struct sbus_connection);
if (!server) {
ret = ENOMEM;
goto done;
}
server->ev = ev;
server->type = SBUS_SERVER;
server->dbus.server = dbus_server;
server->srv_init_fn = init_fn;
server->srv_init_data = init_pvt_data;
talloc_set_destructor((TALLOC_CTX *)server, sbus_server_destructor);
if (use_symlink) {
server->symlink = talloc_strdup(server, symlink_filename);
if (!server->symlink) {
ret = ENOMEM;
goto done;
}
}
/* This structure must be alive while server is alive. That's the
* reason for using server as its talloc context.
*/
ncd = talloc_zero((TALLOC_CTX *)server, struct new_connection_data);
if (!ncd) {
ret = ENOMEM;
goto done;
}
ncd->server = server;
ncd->client_destructor_data = client_destructor_data;
/* Set up D-BUS new connection handler */
dbus_server_set_new_connection_function(server->dbus.server,
sbus_server_init_new_connection,
ncd, NULL);
/* Set up DBusWatch functions */
dbret = dbus_server_set_watch_functions(server->dbus.server,
sbus_add_watch,
sbus_remove_watch,
sbus_toggle_watch,
server, NULL);
if (!dbret) {
DEBUG(SSSDBG_CONF_SETTINGS,
"Error setting up D-BUS server watch functions\n");
ret = EIO;
goto done;
}
/* Set up DBusTimeout functions */
dbret = dbus_server_set_timeout_functions(server->dbus.server,
sbus_add_timeout,
sbus_remove_timeout,
sbus_toggle_timeout,
server, NULL);
if (!dbret) {
DEBUG(SSSDBG_CONF_SETTINGS,
"Error setting up D-BUS server timeout functions\n");
dbus_server_set_watch_functions(server->dbus.server,
NULL, NULL, NULL, NULL, NULL);
ret = EIO;
goto done;
}
*_server = talloc_steal(mem_ctx, server);
ret = EOK;
done:
if (ret != EOK && symlink_filename) {
tmp_ret = unlink(symlink_filename);
/* non-fatal failure */
if (tmp_ret != EOK) {
tmp_ret = errno;
DEBUG(SSSDBG_MINOR_FAILURE,
"Failed to remove symbolic link '%s': %d [%s]!\n",
symlink_filename, tmp_ret, sss_strerror(tmp_ret));
}
}
talloc_free(tmp_ctx);
return ret;
}
static int sbus_server_destructor(void *ctx)
{
struct sbus_connection *server;
errno_t ret;
server = talloc_get_type(ctx, struct sbus_connection);
dbus_server_disconnect(server->dbus.server);
if (server->symlink) {
ret = remove_socket_symlink(server->symlink);
if (ret != EOK) {
DEBUG(SSSDBG_MINOR_FAILURE,
"Could not remove the server symlink\n");
}
}
return 0;
}