chiark / gitweb /
Prep v228: Add remaining updates from upstream (3/3)
[elogind.git] / src / libelogind / sd-bus / sd-bus.c
index eb9525ed71f13013a4a11bcd656f55d451578cf4..7e733cdea0e04000924323a6d91a689d44f87232 100644 (file)
 ***/
 
 #include <endian.h>
-#include <stdlib.h>
-#include <unistd.h>
 #include <netdb.h>
 #include <poll.h>
-#include <sys/mman.h>
 #include <pthread.h>
-
-#include "util.h"
-#include "macro.h"
-#include "strv.h"
-#include "missing.h"
-#include "def.h"
-#include "cgroup-util.h"
-#include "bus-label.h"
+#include <stdlib.h>
+#include <sys/mman.h>
+#include <unistd.h>
 
 #include "sd-bus.h"
+
+#include "alloc-util.h"
+#include "bus-container.h"
+#include "bus-control.h"
 #include "bus-internal.h"
-#include "bus-message.h"
-#include "bus-type.h"
-#include "bus-socket.h"
 #include "bus-kernel.h"
-#include "bus-control.h"
+#include "bus-label.h"
+#include "bus-message.h"
 #include "bus-objects.h"
-#include "bus-util.h"
-#include "bus-container.h"
 #include "bus-protocol.h"
-#include "bus-track.h"
 #include "bus-slot.h"
+#include "bus-socket.h"
+#include "bus-track.h"
+#include "bus-type.h"
+#include "bus-util.h"
+#include "cgroup-util.h"
+#include "def.h"
+#include "fd-util.h"
+#include "hexdecoct.h"
+#include "hostname-util.h"
+#include "macro.h"
+#include "missing.h"
+#include "parse-util.h"
+#include "string-util.h"
+#include "strv.h"
+#include "util.h"
 
 #define log_debug_bus_message(m)                                         \
         do {                                                             \
@@ -68,18 +74,18 @@ static int bus_poll(sd_bus *bus, bool need_more, uint64_t timeout_usec);
 static int attach_io_events(sd_bus *b);
 static void detach_io_events(sd_bus *b);
 
+static thread_local sd_bus *default_system_bus = NULL;
+// UNNEEDED static thread_local sd_bus *default_user_bus = NULL;
+static thread_local sd_bus *default_starter_bus = NULL;
+
 static void bus_close_fds(sd_bus *b) {
         assert(b);
 
         detach_io_events(b);
 
-        if (b->input_fd >= 0)
-                safe_close(b->input_fd);
-
-        if (b->output_fd >= 0 && b->output_fd != b->input_fd)
+        if (b->input_fd != b->output_fd)
                 safe_close(b->output_fd);
-
-        b->input_fd = b->output_fd = -1;
+        b->output_fd = b->input_fd = safe_close(b->input_fd);
 }
 
 static void bus_reset_queues(sd_bus *b) {
@@ -88,15 +94,13 @@ static void bus_reset_queues(sd_bus *b) {
         while (b->rqueue_size > 0)
                 sd_bus_message_unref(b->rqueue[--b->rqueue_size]);
 
-        free(b->rqueue);
-        b->rqueue = NULL;
+        b->rqueue = mfree(b->rqueue);
         b->rqueue_allocated = 0;
 
         while (b->wqueue_size > 0)
                 sd_bus_message_unref(b->wqueue[--b->wqueue_size]);
 
-        free(b->wqueue);
-        b->wqueue = NULL;
+        b->wqueue = mfree(b->wqueue);
         b->wqueue_allocated = 0;
 }
 
@@ -220,8 +224,8 @@ _public_ int sd_bus_set_address(sd_bus *bus, const char *address) {
 _public_ int sd_bus_set_fd(sd_bus *bus, int input_fd, int output_fd) {
         assert_return(bus, -EINVAL);
         assert_return(bus->state == BUS_UNSET, -EPERM);
-        assert_return(input_fd >= 0, -EINVAL);
-        assert_return(output_fd >= 0, -EINVAL);
+        assert_return(input_fd >= 0, -EBADF);
+        assert_return(output_fd >= 0, -EBADF);
         assert_return(!bus_pid_changed(bus), -ECHILD);
 
         bus->input_fd = input_fd;
@@ -304,7 +308,6 @@ _public_ int sd_bus_negotiate_timestamp(sd_bus *bus, int b) {
 
         return 0;
 }
-#endif // 0
 
 _public_ int sd_bus_negotiate_creds(sd_bus *bus, int b, uint64_t mask) {
         uint64_t new_flags;
@@ -345,8 +348,6 @@ _public_ int sd_bus_set_server(sd_bus *bus, int b, sd_id128_t server_id) {
         return 0;
 }
 
-/// UNNEEDED by elogind
-#if 0
 _public_ int sd_bus_set_anonymous(sd_bus *bus, int b) {
         assert_return(bus, -EINVAL);
         assert_return(bus->state == BUS_UNSET, -EPERM);
@@ -834,8 +835,7 @@ static int parse_container_unix_address(sd_bus *b, const char **p, char **guid)
                 b->machine = machine;
                 machine = NULL;
         } else {
-                free(b->machine);
-                b->machine = NULL;
+                b->machine = mfree(b->machine);
         }
 
         if (pid) {
@@ -894,8 +894,7 @@ static int parse_container_kernel_address(sd_bus *b, const char **p, char **guid
                 b->machine = machine;
                 machine = NULL;
         } else {
-                free(b->machine);
-                b->machine = NULL;
+                b->machine = mfree(b->machine);
         }
 
         if (pid) {
@@ -905,10 +904,9 @@ static int parse_container_kernel_address(sd_bus *b, const char **p, char **guid
         } else
                 b->nspid = 0;
 
-        free(b->kernel);
-        b->kernel = strdup("/sys/fs/kdbus/0-system/bus");
-        if (!b->kernel)
-                return -ENOMEM;
+        r = free_and_strdup(&b->kernel, "/sys/fs/kdbus/0-system/bus");
+        if (r < 0)
+                return r;
 
         return 0;
 }
@@ -918,15 +916,11 @@ static void bus_reset_parsed_address(sd_bus *b) {
 
         zero(b->sockaddr);
         b->sockaddr_size = 0;
-        strv_free(b->exec_argv);
-        free(b->exec_path);
-        b->exec_path = NULL;
-        b->exec_argv = NULL;
+        b->exec_argv = strv_free(b->exec_argv);
+        b->exec_path = mfree(b->exec_path);
         b->server_id = SD_ID128_NULL;
-        free(b->kernel);
-        b->kernel = NULL;
-        free(b->machine);
-        b->machine = NULL;
+        b->kernel = mfree(b->kernel);
+        b->machine = mfree(b->machine);
         b->nspid = 0;
 }
 
@@ -1021,6 +1015,8 @@ static int bus_parse_next_address(sd_bus *b) {
 }
 
 static int bus_start_address(sd_bus *b) {
+        bool container_kdbus_available = false;
+        bool kdbus_available = false;
         int r;
 
         assert(b);
@@ -1030,19 +1026,40 @@ static int bus_start_address(sd_bus *b) {
 
                 bus_close_fds(b);
 
+                /*
+                 * Usually, if you provide multiple different bus-addresses, we
+                 * try all of them in order. We use the first one that
+                 * succeeds. However, if you mix kernel and unix addresses, we
+                 * never try unix-addresses if a previous kernel address was
+                 * tried and kdbus was available. This is required to prevent
+                 * clients to fallback to the bus-proxy if kdbus is available
+                 * but failed (eg., too many connections).
+                 */
+
                 if (b->exec_path)
                         r = bus_socket_exec(b);
-#if 0
-               else if ((b->nspid > 0 || b->machine) && b->kernel)
+                else if ((b->nspid > 0 || b->machine) && b->kernel) {
                         r = bus_container_connect_kernel(b);
-                else if ((b->nspid > 0 || b->machine) && b->sockaddr.sa.sa_family != AF_UNSPEC)
-                        r = bus_container_connect_socket(b);
-#endif // 0
-                else if (b->kernel)
+                        if (r < 0 && !IN_SET(r, -ENOENT, -ESOCKTNOSUPPORT))
+                                container_kdbus_available = true;
+
+                } else if ((b->nspid > 0 || b->machine) && b->sockaddr.sa.sa_family != AF_UNSPEC) {
+                        if (!container_kdbus_available)
+                                r = bus_container_connect_socket(b);
+                        else
+                                skipped = true;
+
+                } else if (b->kernel) {
                         r = bus_kernel_connect(b);
-                else if (b->sockaddr.sa.sa_family != AF_UNSPEC)
-                        r = bus_socket_connect(b);
-                else
+                        if (r < 0 && !IN_SET(r, -ENOENT, -ESOCKTNOSUPPORT))
+                                kdbus_available = true;
+
+                } else if (b->sockaddr.sa.sa_family != AF_UNSPEC) {
+                        if (!kdbus_available)
+                                r = bus_socket_connect(b);
+                        else
+                                skipped = true;
+                } else
                         skipped = true;
 
                 if (!skipped) {
@@ -1147,12 +1164,21 @@ _public_ int sd_bus_open(sd_bus **ret) {
         if (e) {
                 if (streq(e, "system"))
                         return sd_bus_open_system(ret);
+/// elogind does not support systemd units
+#if 0
                 else if (STR_IN_SET(e, "session", "user"))
                         return sd_bus_open_user(ret);
+#endif // 0
         }
 
         e = secure_getenv("DBUS_STARTER_ADDRESS");
         if (!e) {
+/// elogind does not support systemd units
+#if 0
+                if (cg_pid_get_owner_uid(0, NULL) >= 0)
+                        return sd_bus_open_user(ret);
+                else
+#endif // 0
                 return sd_bus_open_system(ret);
         }
 
@@ -1230,8 +1256,12 @@ fail:
         return r;
 }
 
+/// elogind can not open/use a user bus
+#if 0
 int bus_set_address_user(sd_bus *b) {
         const char *e;
+        uid_t uid;
+        int r;
 
         assert(b);
 
@@ -1239,6 +1269,10 @@ int bus_set_address_user(sd_bus *b) {
         if (e)
                 return sd_bus_set_address(b, e);
 
+        r = cg_pid_get_owner_uid(0, &uid);
+        if (r < 0)
+                uid = getuid();
+
         e = secure_getenv("XDG_RUNTIME_DIR");
         if (e) {
                 _cleanup_free_ char *ee = NULL;
@@ -1247,17 +1281,20 @@ int bus_set_address_user(sd_bus *b) {
                 if (!ee)
                         return -ENOMEM;
 
-                (void) asprintf(&b->address, KERNEL_USER_BUS_ADDRESS_FMT ";" UNIX_USER_BUS_ADDRESS_FMT, getuid(), ee);
+                (void) asprintf(&b->address, KERNEL_USER_BUS_ADDRESS_FMT ";" UNIX_USER_BUS_ADDRESS_FMT, uid, ee);
         } else
-                (void) asprintf(&b->address, KERNEL_USER_BUS_ADDRESS_FMT, getuid());
+                (void) asprintf(&b->address, KERNEL_USER_BUS_ADDRESS_FMT, uid);
 
         if (!b->address)
                 return -ENOMEM;
 
         return 0;
 }
+#endif // 0
 
 _public_ int sd_bus_open_user(sd_bus **ret) {
+/// elogind does not support user buses
+#if 0
         sd_bus *b;
         int r;
 
@@ -1288,6 +1325,9 @@ _public_ int sd_bus_open_user(sd_bus **ret) {
 fail:
         bus_free(b);
         return r;
+#else
+        return sd_bus_open_system(ret);
+#endif // 0
 }
 
 int bus_set_address_system_remote(sd_bus *b, const char *host) {
@@ -1809,6 +1849,8 @@ _public_ int sd_bus_send(sd_bus *bus, sd_bus_message *m, uint64_t *cookie) {
         return bus_send_internal(bus, m, cookie, false);
 }
 
+/// UNNEEDED by elogind
+#if 0
 _public_ int sd_bus_send_to(sd_bus *bus, sd_bus_message *m, const char *destination, uint64_t *cookie) {
         int r;
 
@@ -1834,6 +1876,7 @@ _public_ int sd_bus_send_to(sd_bus *bus, sd_bus_message *m, const char *destinat
 
         return sd_bus_send(bus, m, cookie);
 }
+#endif // 0
 
 static usec_t calc_elapse(uint64_t usec) {
         if (usec == (uint64_t) -1)
@@ -1973,37 +2016,39 @@ _public_ int sd_bus_call(
         unsigned i;
         int r;
 
-        assert_return(m, -EINVAL);
-        assert_return(m->header->type == SD_BUS_MESSAGE_METHOD_CALL, -EINVAL);
-        assert_return(!(m->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED), -EINVAL);
-        assert_return(!bus_error_is_dirty(error), -EINVAL);
+        bus_assert_return(m, -EINVAL, error);
+        bus_assert_return(m->header->type == SD_BUS_MESSAGE_METHOD_CALL, -EINVAL, error);
+        bus_assert_return(!(m->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED), -EINVAL, error);
+        bus_assert_return(!bus_error_is_dirty(error), -EINVAL, error);
 
         if (!bus)
                 bus = m->bus;
 
-        assert_return(!bus_pid_changed(bus), -ECHILD);
-        assert_return(!bus->is_kernel || !(bus->hello_flags & KDBUS_HELLO_MONITOR), -EROFS);
+        bus_assert_return(!bus_pid_changed(bus), -ECHILD, error);
+        bus_assert_return(!bus->is_kernel || !(bus->hello_flags & KDBUS_HELLO_MONITOR), -EROFS, error);
 
-        if (!BUS_IS_OPEN(bus->state))
-                return -ENOTCONN;
+        if (!BUS_IS_OPEN(bus->state)) {
+                r = -ENOTCONN;
+                goto fail;
+        }
 
         r = bus_ensure_running(bus);
         if (r < 0)
-                return r;
+                goto fail;
 
         i = bus->rqueue_size;
 
         r = bus_seal_message(bus, m, usec);
         if (r < 0)
-                return r;
+                goto fail;
 
         r = bus_remarshal_message(bus, &m);
         if (r < 0)
-                return r;
+                goto fail;
 
         r = bus_send_internal(bus, m, &cookie, true);
         if (r < 0)
-                return r;
+                goto fail;
 
         timeout = calc_elapse(m->timeout);
 
@@ -2034,14 +2079,17 @@ _public_ int sd_bus_call(
                                         }
 
                                         r = sd_bus_error_setf(error, SD_BUS_ERROR_INCONSISTENT_MESSAGE, "Reply message contained file descriptors which I couldn't accept. Sorry.");
+                                        sd_bus_message_unref(incoming);
+                                        return r;
 
-                                } else if (incoming->header->type == SD_BUS_MESSAGE_METHOD_ERROR)
+                                } else if (incoming->header->type == SD_BUS_MESSAGE_METHOD_ERROR) {
                                         r = sd_bus_error_copy(error, &incoming->error);
-                                else
-                                        r = -EIO;
-
                                 sd_bus_message_unref(incoming);
                                 return r;
+                                } else {
+                                        r = -EIO;
+                                        goto fail;
+                                }
 
                         } else if (BUS_MESSAGE_COOKIE(incoming) == cookie &&
                                    bus->unique_name &&
@@ -2057,7 +2105,8 @@ _public_ int sd_bus_call(
                                  * immediately. */
 
                                 sd_bus_message_unref(incoming);
-                                return -ELOOP;
+                                r = -ELOOP;
+                                goto fail;
                         }
 
                         /* Try to read more, right-away */
@@ -2068,10 +2117,10 @@ _public_ int sd_bus_call(
                 if (r < 0) {
                         if (r == -ENOTCONN || r == -ECONNRESET || r == -EPIPE || r == -ESHUTDOWN) {
                                 bus_enter_closing(bus);
-                                return -ECONNRESET;
+                                r = -ECONNRESET;
                         }
 
-                        return r;
+                        goto fail;
                 }
                 if (r > 0)
                         continue;
@@ -2080,8 +2129,10 @@ _public_ int sd_bus_call(
                         usec_t n;
 
                         n = now(CLOCK_MONOTONIC);
-                        if (n >= timeout)
-                                return -ETIMEDOUT;
+                        if (n >= timeout) {
+                                r = -ETIMEDOUT;
+                                goto fail;
+                        }
 
                         left = timeout - n;
                 } else
@@ -2089,22 +2140,29 @@ _public_ int sd_bus_call(
 
                 r = bus_poll(bus, true, left);
                 if (r < 0)
-                        return r;
-                if (r == 0)
-                        return -ETIMEDOUT;
+                        goto fail;
+                if (r == 0) {
+                        r = -ETIMEDOUT;
+                        goto fail;
+                }
 
                 r = dispatch_wqueue(bus);
                 if (r < 0) {
                         if (r == -ENOTCONN || r == -ECONNRESET || r == -EPIPE || r == -ESHUTDOWN) {
                                 bus_enter_closing(bus);
-                                return -ECONNRESET;
+                                r = -ECONNRESET;
                         }
 
-                        return r;
+                        goto fail;
                 }
         }
+
+fail:
+        return sd_bus_error_set_errno(error, r);
 }
 
+/// UNNEEDED by elogind
+#if 0
 _public_ int sd_bus_get_fd(sd_bus *bus) {
 
         assert_return(bus, -EINVAL);
@@ -2113,6 +2171,7 @@ _public_ int sd_bus_get_fd(sd_bus *bus) {
 
         return bus->input_fd;
 }
+#endif // 0
 
 _public_ int sd_bus_get_events(sd_bus *bus) {
         int flags = 0;
@@ -2910,6 +2969,8 @@ _public_ int sd_bus_flush(sd_bus *bus) {
         }
 }
 
+/// UNNEEDED by elogind
+#if 0
 _public_ int sd_bus_add_filter(
                 sd_bus *bus,
                 sd_bus_slot **slot,
@@ -2936,6 +2997,7 @@ _public_ int sd_bus_add_filter(
 
         return 0;
 }
+#endif // 0
 
 _public_ int sd_bus_add_match(
                 sd_bus *bus,
@@ -3339,15 +3401,17 @@ static int bus_default(int (*bus_open)(sd_bus **), sd_bus **default_bus, sd_bus
 }
 
 _public_ int sd_bus_default_system(sd_bus **ret) {
-        static thread_local sd_bus *default_system_bus = NULL;
-
         return bus_default(sd_bus_open_system, &default_system_bus, ret);
 }
 
-_public_ int sd_bus_default_user(sd_bus **ret) {
-        static thread_local sd_bus *default_user_bus = NULL;
 
+_public_ int sd_bus_default_user(sd_bus **ret) {
+/// elogind does not support user buses
+#if 0
         return bus_default(sd_bus_open_user, &default_user_bus, ret);
+#else
+        return sd_bus_default_system(ret);
+#endif // 0
 }
 
 _public_ int sd_bus_default(sd_bus **ret) {
@@ -3364,8 +3428,11 @@ _public_ int sd_bus_default(sd_bus **ret) {
         if (e) {
                 if (streq(e, "system"))
                         return sd_bus_default_system(ret);
+/// elogind does not support systemd units
+#if 0
                 else if (STR_IN_SET(e, "user", "session"))
                         return sd_bus_default_user(ret);
+#endif // 0
         }
 
         /* No type is specified, so we have not other option than to
@@ -3373,7 +3440,6 @@ _public_ int sd_bus_default(sd_bus **ret) {
 
         e = secure_getenv("DBUS_STARTER_ADDRESS");
         if (e) {
-                static thread_local sd_bus *default_starter_bus = NULL;
 
                 return bus_default(sd_bus_open, &default_starter_bus, ret);
         }
@@ -3381,6 +3447,12 @@ _public_ int sd_bus_default(sd_bus **ret) {
         /* Finally, if nothing is set use the cached connection for
          * the right scope */
 
+/// elogind does not support systemd units
+#if 0
+        if (cg_pid_get_owner_uid(0, NULL) >= 0)
+                return sd_bus_default_user(ret);
+        else
+#endif // 0
         return sd_bus_default_system(ret);
 }
 
@@ -3443,7 +3515,171 @@ _public_ int sd_bus_path_decode(const char *path, const char *prefix, char **ext
         *external_id = ret;
         return 1;
 }
-#endif // 0
+
+_public_ int sd_bus_path_encode_many(char **out, const char *path_template, ...) {
+        _cleanup_strv_free_ char **labels = NULL;
+        char *path, *path_pos, **label_pos;
+        const char *sep, *template_pos;
+        size_t path_length;
+        va_list list;
+        int r;
+
+        assert_return(out, -EINVAL);
+        assert_return(path_template, -EINVAL);
+
+        path_length = strlen(path_template);
+
+        va_start(list, path_template);
+        for (sep = strchr(path_template, '%'); sep; sep = strchr(sep + 1, '%')) {
+                const char *arg;
+                char *label;
+
+                arg = va_arg(list, const char *);
+                if (!arg) {
+                        va_end(list);
+                        return -EINVAL;
+                }
+
+                label = bus_label_escape(arg);
+                if (!label) {
+                        va_end(list);
+                        return -ENOMEM;
+                }
+
+                r = strv_consume(&labels, label);
+                if (r < 0) {
+                        va_end(list);
+                        return r;
+                }
+
+                /* add label length, but account for the format character */
+                path_length += strlen(label) - 1;
+        }
+        va_end(list);
+
+        path = malloc(path_length + 1);
+        if (!path)
+                return -ENOMEM;
+
+        path_pos = path;
+        label_pos = labels;
+
+        for (template_pos = path_template; *template_pos; ) {
+                sep = strchrnul(template_pos, '%');
+                path_pos = mempcpy(path_pos, template_pos, sep - template_pos);
+                if (!*sep)
+                        break;
+
+                path_pos = stpcpy(path_pos, *label_pos++);
+                template_pos = sep + 1;
+        }
+
+        *path_pos = 0;
+        *out = path;
+        return 0;
+}
+
+_public_ int sd_bus_path_decode_many(const char *path, const char *path_template, ...) {
+        _cleanup_strv_free_ char **labels = NULL;
+        const char *template_pos, *path_pos;
+        char **label_pos;
+        va_list list;
+        int r;
+
+        /*
+         * This decodes an object-path based on a template argument. The
+         * template consists of a verbatim path, optionally including special
+         * directives:
+         *
+         *   - Each occurrence of '%' in the template matches an arbitrary
+         *     substring of a label in the given path. At most one such
+         *     directive is allowed per label. For each such directive, the
+         *     caller must provide an output parameter (char **) via va_arg. If
+         *     NULL is passed, the given label is verified, but not returned.
+         *     For each matched label, the *decoded* label is stored in the
+         *     passed output argument, and the caller is responsible to free
+         *     it. Note that the output arguments are only modified if the
+         *     actualy path matched the template. Otherwise, they're left
+         *     untouched.
+         *
+         * This function returns <0 on error, 0 if the path does not match the
+         * template, 1 if it matched.
+         */
+
+        assert_return(path, -EINVAL);
+        assert_return(path_template, -EINVAL);
+
+        path_pos = path;
+
+        for (template_pos = path_template; *template_pos; ) {
+                const char *sep;
+                size_t length;
+                char *label;
+
+                /* verify everything until the next '%' matches verbatim */
+                sep = strchrnul(template_pos, '%');
+                length = sep - template_pos;
+                if (strncmp(path_pos, template_pos, length))
+                        return 0;
+
+                path_pos += length;
+                template_pos += length;
+
+                if (!*template_pos)
+                        break;
+
+                /* We found the next '%' character. Everything up until here
+                 * matched. We now skip ahead to the end of this label and make
+                 * sure it matches the tail of the label in the path. Then we
+                 * decode the string in-between and save it for later use. */
+
+                ++template_pos; /* skip over '%' */
+
+                sep = strchrnul(template_pos, '/');
+                length = sep - template_pos; /* length of suffix to match verbatim */
+
+                /* verify the suffixes match */
+                sep = strchrnul(path_pos, '/');
+                if (sep - path_pos < (ssize_t)length ||
+                    strncmp(sep - length, template_pos, length))
+                        return 0;
+
+                template_pos += length; /* skip over matched label */
+                length = sep - path_pos - length; /* length of sub-label to decode */
+
+                /* store unescaped label for later use */
+                label = bus_label_unescape_n(path_pos, length);
+                if (!label)
+                        return -ENOMEM;
+
+                r = strv_consume(&labels, label);
+                if (r < 0)
+                        return r;
+
+                path_pos = sep; /* skip decoded label and suffix */
+        }
+
+        /* end of template must match end of path */
+        if (*path_pos)
+                return 0;
+
+        /* copy the labels over to the caller */
+        va_start(list, path_template);
+        for (label_pos = labels; label_pos && *label_pos; ++label_pos) {
+                char **arg;
+
+                arg = va_arg(list, char **);
+                if (arg)
+                        *arg = *label_pos;
+                else
+                        free(*label_pos);
+        }
+        va_end(list);
+
+        free(labels);
+        labels = NULL;
+        return 1;
+}
 
 _public_ int sd_bus_try_close(sd_bus *bus) {
         int r;
@@ -3471,8 +3707,6 @@ _public_ int sd_bus_try_close(sd_bus *bus) {
         return 0;
 }
 
-/// UNNEEDED by elogind
-#if 0
 _public_ int sd_bus_get_description(sd_bus *bus, const char **description) {
         assert_return(bus, -EINVAL);
         assert_return(description, -EINVAL);
@@ -3601,4 +3835,21 @@ _public_ int sd_bus_is_monitor(sd_bus *bus) {
 
         return !!(bus->hello_flags & KDBUS_HELLO_MONITOR);
 }
+
+static void flush_close(sd_bus *bus) {
+        if (!bus)
+                return;
+
+        /* Flushes and closes the specified bus. We take a ref before,
+         * to ensure the flushing does not cause the bus to be
+         * unreferenced. */
+
+        sd_bus_flush_close_unref(sd_bus_ref(bus));
+}
+
+_public_ void sd_bus_default_flush_close(void) {
+        flush_close(default_starter_bus);
+        flush_close(default_user_bus);
+        flush_close(default_system_bus);
+}
 #endif // 0