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authorJakub Hrozek <jhrozek@redhat.com>2011-10-06 18:53:51 +0200
committerStephen Gallagher <sgallagh@redhat.com>2011-10-13 13:18:14 -0400
commit2c9a76e553f9239eaa91f32ccaf18b7a68316ce5 (patch)
treecac712d5877da316dcb7732df93c0ef953b51600 /src/sbus/sssd_dbus_server.c
parentfe9cea3352b919f81ead0de5487ed593325b2ef0 (diff)
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Append PID to sbus server socket name, let clients use a symlink
https://fedorahosted.org/sssd/ticket/1034
Diffstat (limited to 'src/sbus/sssd_dbus_server.c')
-rw-r--r--src/sbus/sssd_dbus_server.c186
1 files changed, 169 insertions, 17 deletions
diff --git a/src/sbus/sssd_dbus_server.c b/src/sbus/sssd_dbus_server.c
index fdcbc4ff..759eb69f 100644
--- a/src/sbus/sssd_dbus_server.c
+++ b/src/sbus/sssd_dbus_server.c
@@ -81,6 +81,97 @@ static void sbus_server_init_new_connection(DBusServer *dbus_server,
}
}
+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(7, ("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? */
+ ret = unlink(symlink_filename);
+ if (ret != 0) {
+ DEBUG(1, ("Cannot remove old symlink: [%d][%s].\n",
+ ret, strerror(ret)));
+ return EIO;
+ }
+ errno = 0;
+ ret = symlink(filename, symlink_filename);
+ }
+
+ if (ret != 0) {
+ ret = errno;
+ DEBUG(1, ("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);
+ if (numread < 0) {
+ ret = errno;
+ DEBUG(2, ("readlink failed [%d]: %s\n", ret, strerror(ret)));
+ return ret;
+ }
+ target[numread] = '\0';
+ DEBUG(9, ("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(2, ("snprintf failed"));
+ return EIO;
+ } else if (ret >= PATH_MAX) {
+ DEBUG(2, ("path too long?!?!\n"));
+ return EIO;
+ }
+ DEBUG(9, ("The path including our pid is [%s]\n", pidpath));
+
+ if (strcmp(pidpath, target) != 0) {
+ DEBUG(4, ("Will not remove symlink, seems to be owned by "
+ "another process\n"));
+ return EOK;
+ }
+
+ ret = unlink(symlink_name);
+ if (ret != 0) {
+ ret = errno;
+ DEBUG(2, ("unlink failed to remove [%s] [%d]: %s\n",
+ symlink, ret, strerror(ret)));
+ return ret;
+ }
+
+ DEBUG(9, ("Removed the symlink\n"));
+ return EOK;
+}
+
/*
* dbus_new_server
* Set up a D-BUS server, integrate with the event loop
@@ -90,8 +181,10 @@ int sbus_new_server(TALLOC_CTX *mem_ctx,
struct tevent_context *ev,
const char *address,
struct sbus_interface *intf,
+ bool use_symlink,
struct sbus_connection **_server,
- sbus_server_conn_init_fn init_fn, void *init_pvt_data)
+ sbus_server_conn_init_fn init_fn,
+ void *init_pvt_data)
{
struct sbus_connection *server;
DBusServer *dbus_server;
@@ -100,30 +193,64 @@ int sbus_new_server(TALLOC_CTX *mem_ctx,
char *tmp;
int ret;
char *filename;
+ char *symlink_filename = NULL;
+ const char *socket_address;
struct stat stat_buf;
+ TALLOC_CTX *tmp_ctx;
*_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(address, &dbus_error);
+ dbus_server = dbus_server_listen(socket_address, &dbus_error);
if (!dbus_server) {
DEBUG(1,("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);
- return EIO;
+ ret = EIO;
+ goto done;
}
- filename = strchr(address, '/');
+ filename = strchr(socket_address, '/');
if (filename == NULL) {
- DEBUG(1, ("Unexpected dbus address [%s].\n", address));
- return EIO;
+ DEBUG(1, ("Unexpected dbus address [%s].\n", socket_address));
+ ret = EIO;
+ goto done;
+ }
+
+ if (use_symlink) {
+ symlink_filename = strchr(address, '/');
+ if (symlink_filename == NULL) {
+ DEBUG(1, ("Unexpected dbus address [%s].\n", address));
+ ret = EIO;
+ goto done;
+ }
+
+ ret = create_socket_symlink(filename, symlink_filename);
+ if (ret != EOK) {
+ DEBUG(1, ("Could not create symlink [%d]: %s\n",
+ ret, strerror(ret)));
+ ret = EIO;
+ goto done;
+ }
}
- ret = check_file(filename, 0, 0, -1, CHECK_SOCK, &stat_buf, false);
+ /* Both check_file and chmod can handle both the symlink and
+ * the socket */
+ ret = check_file(filename, 0, 0, -1, CHECK_SOCK, &stat_buf, true);
if (ret != EOK) {
DEBUG(1, ("check_file failed for [%s].\n", filename));
- return EIO;
+ ret = EIO;
+ goto done;
}
if ((stat_buf.st_mode & ~S_IFMT) != 0600) {
@@ -131,7 +258,8 @@ int sbus_new_server(TALLOC_CTX *mem_ctx,
if (ret != EOK) {
DEBUG(1, ("chmod failed for [%s]: [%d][%s].\n", filename, errno,
strerror(errno)));
- return EIO;
+ ret = EIO;
+ goto done;
}
}
@@ -139,9 +267,10 @@ int sbus_new_server(TALLOC_CTX *mem_ctx,
DEBUG(3, ("D-BUS Server listening on %s\n", tmp));
free(tmp);
- server = talloc_zero(mem_ctx, struct sbus_connection);
+ server = talloc_zero(tmp_ctx, struct sbus_connection);
if (!server) {
- return ENOMEM;
+ ret = ENOMEM;
+ goto done;
}
server->ev = ev;
@@ -153,6 +282,14 @@ int sbus_new_server(TALLOC_CTX *mem_ctx,
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;
+ }
+ }
+
/* Set up D-BUS new connection handler */
dbus_server_set_new_connection_function(server->dbus.server,
sbus_server_init_new_connection,
@@ -166,8 +303,8 @@ int sbus_new_server(TALLOC_CTX *mem_ctx,
server, NULL);
if (!dbret) {
DEBUG(4, ("Error setting up D-BUS server watch functions\n"));
- talloc_free(server);
- return EIO;
+ ret = EIO;
+ goto done;
}
/* Set up DBusTimeout functions */
@@ -180,19 +317,34 @@ int sbus_new_server(TALLOC_CTX *mem_ctx,
DEBUG(4,("Error setting up D-BUS server timeout functions\n"));
dbus_server_set_watch_functions(server->dbus.server,
NULL, NULL, NULL, NULL, NULL);
- talloc_free(server);
- return EIO;
+ ret = EIO;
+ goto done;
}
- *_server = server;
- return EOK;
+ *_server = talloc_steal(mem_ctx, server);
+ ret = EOK;
+done:
+ if (ret != EOK && symlink_filename) {
+ unlink(symlink_filename);
+ }
+ 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(3, ("Could not remove the server symlink\n"));
+ }
+ }
+
return 0;
}