sd-bus: sync with kdbus upstream (ABI break)

kdbus has seen a larger update than expected lately, most notably with
kdbusfs, a file system to expose the kdbus control files:

 * Each time a file system of this type is mounted, a new kdbus
   domain is created.

 * The layout inside each mount point is the same as before, except
   that domains are not hierarchically nested anymore.

 * Domains are therefore also unnamed now.

 * Unmounting a kdbusfs will automatically also detroy the
   associated domain.

 * Hence, the action of creating a kdbus domain is now as
   privileged as mounting a filesystem.

 * This way, we can get around creating dev nodes for everything,
   which is last but not least something that is not limited by
   20-bit minor numbers.

The kdbus specific bits in nspawn have all been dropped now, as nspawn
can rely on the container OS to set up its own kdbus domain, simply by
mounting a new instance.

A new set of mounts has been added to mount things *after* the kernel
modules have been loaded. For now, only kdbus is in this set, which is
invoked with mount_setup_late().

5 files changed, 28 insertions, 85 deletions

diff --git a/src/libsystemd/sd-bus/PORTING-DBUS1 b/src/libsystemd/sd-bus/PORTING-DBUS1
index 81e94132b3..2dedb28bcf 100644
--- a/src/libsystemd/sd-bus/PORTING-DBUS1
+++ b/src/libsystemd/sd-bus/PORTING-DBUS1
@@ -14,11 +14,11 @@ GVariant compatible marshaler to your library first.
 
 After you have done that: here's the basic principle how kdbus works:
 
-You connect to a bus by opening its bus node in /dev/kdbus/. All
+You connect to a bus by opening its bus node in /sys/fs/kdbus/. All
 buses have a device node there, it starts with a numeric UID of the
 owner of the bus, followed by a dash and a string identifying the
-bus. The system bus is thus called /dev/kdbus/0-system, and for user
-buses the device node is /dev/kdbus/1000-user (if 1000 is your user
+bus. The system bus is thus called /sys/fs/kdbus/0-system, and for user
+buses the device node is /sys/fs/kdbus/1000-user (if 1000 is your user
 id).
 
 (Before we proceed, please always keep a copy of libsystemd next
@@ -496,12 +496,12 @@ parameter.
 Client libraries should use the following connection string when
 connecting to the system bus:
 
-   kernel:path=/dev/kdbus/0-system/bus;unix:path=/var/run/dbus/system_bus_socket
+   kernel:path=/sys/fs/kdbus/0-system/bus;unix:path=/var/run/dbus/system_bus_socket
 
 This will ensure that kdbus is preferred over the legacy AF_UNIX
 socket, but compatibility is kept. For the user bus use:
 
-   kernel:path=/dev/kdbus/$UID-user/bus;unix:path=$XDG_RUNTIME_DIR/bus
+   kernel:path=/sys/fs/kdbus/$UID-user/bus;unix:path=$XDG_RUNTIME_DIR/bus
 
 With $UID replaced by the callers numer user ID, and $XDG_RUNTIME_DIR
 following the XDG basedir spec.
diff --git a/src/libsystemd/sd-bus/bus-kernel.c b/src/libsystemd/sd-bus/bus-kernel.c
index 5e7bc12239..afac3b6bcc 100644
--- a/src/libsystemd/sd-bus/bus-kernel.c
+++ b/src/libsystemd/sd-bus/bus-kernel.c
@@ -1282,7 +1282,7 @@ int bus_kernel_create_bus(const char *name, bool world, char **s) {
         assert(name);
         assert(s);
 
-        fd = open("/dev/kdbus/control", O_RDWR|O_NOCTTY|O_CLOEXEC);
+        fd = open("/sys/fs/kdbus/control", O_RDWR|O_NOCTTY|O_CLOEXEC);
         if (fd < 0)
                 return -errno;
 
@@ -1323,7 +1323,7 @@ int bus_kernel_create_bus(const char *name, bool world, char **s) {
         if (s) {
                 char *p;
 
-                p = strjoin("/dev/kdbus/", n->str, "/bus", NULL);
+                p = strjoin("/sys/fs/kdbus/", n->str, "/bus", NULL);
                 if (!p) {
                         safe_close(fd);
                         return -ENOMEM;
@@ -1403,7 +1403,7 @@ int bus_kernel_open_bus_fd(const char *bus, char **path) {
         int fd;
         size_t len;
 
-        len = strlen("/dev/kdbus/") + DECIMAL_STR_MAX(uid_t) + 1 + strlen(bus) + strlen("/bus") + 1;
+        len = strlen("/sys/fs/kdbus/") + DECIMAL_STR_MAX(uid_t) + 1 + strlen(bus) + strlen("/bus") + 1;
 
         if (path) {
                 p = malloc(len);
@@ -1412,7 +1412,7 @@ int bus_kernel_open_bus_fd(const char *bus, char **path) {
                 *path = p;
         } else
                 p = alloca(len);
-        sprintf(p, "/dev/kdbus/" UID_FMT "-%s/bus", getuid(), bus);
+        sprintf(p, "/sys/fs/kdbus/" UID_FMT "-%s/bus", getuid(), bus);
 
         fd = open(p, O_RDWR|O_NOCTTY|O_CLOEXEC);
         if (fd < 0)
@@ -1585,58 +1585,6 @@ int bus_kernel_make_starter(
         return fd;
 }
 
-int bus_kernel_create_domain(const char *name, char **s) {
-        struct kdbus_cmd_make *make;
-        struct kdbus_item *n;
-        int fd;
-
-        assert(name);
-        assert(s);
-
-        fd = open("/dev/kdbus/control", O_RDWR|O_NOCTTY|O_CLOEXEC);
-        if (fd < 0)
-                return -errno;
-
-        make = alloca0_align(ALIGN8(offsetof(struct kdbus_cmd_make, items) +
-                                    offsetof(struct kdbus_item, str) +
-                                    strlen(name) + 1),
-                             8);
-
-        n = make->items;
-        strcpy(n->str, name);
-        n->size = offsetof(struct kdbus_item, str) + strlen(n->str) + 1;
-        n->type = KDBUS_ITEM_MAKE_NAME;
-
-        make->size = ALIGN8(offsetof(struct kdbus_cmd_make, items) + n->size);
-        make->flags = KDBUS_MAKE_ACCESS_WORLD;
-
-        if (ioctl(fd, KDBUS_CMD_DOMAIN_MAKE, make) < 0) {
-                safe_close(fd);
-                return -errno;
-        }
-
-        /* The higher 32bit of the flags field are considered
-         * 'incompatible flags'. Refuse them all for now. */
-        if (make->flags > 0xFFFFFFFFULL) {
-                safe_close(fd);
-                return -ENOTSUP;
-        }
-
-        if (s) {
-                char *p;
-
-                p = strappend("/dev/kdbus/domain/", name);
-                if (!p) {
-                        safe_close(fd);
-                        return -ENOMEM;
-                }
-
-                *s = p;
-        }
-
-        return fd;
-}
-
 int bus_kernel_try_close(sd_bus *bus) {
         assert(bus);
         assert(bus->is_kernel);
diff --git a/src/libsystemd/sd-bus/bus-kernel.h b/src/libsystemd/sd-bus/bus-kernel.h
index f1d832a764..c1ee285cd1 100644
--- a/src/libsystemd/sd-bus/bus-kernel.h
+++ b/src/libsystemd/sd-bus/bus-kernel.h
@@ -71,7 +71,6 @@ int bus_kernel_make_starter(int fd, const char *name, bool activating, bool acce
 
 int bus_kernel_create_bus(const char *name, bool world, char **s);
 int bus_kernel_create_endpoint(const char *bus_name, const char *ep_name, char **path);
-int bus_kernel_create_domain(const char *name, char **s);
 
 int bus_kernel_set_endpoint_policy(int fd, uid_t uid, BusEndpoint *ep);
 
diff --git a/src/libsystemd/sd-bus/kdbus.h b/src/libsystemd/sd-bus/kdbus.h
index a870b176cf..e3a80c352d 100644
--- a/src/libsystemd/sd-bus/kdbus.h
+++ b/src/libsystemd/sd-bus/kdbus.h
@@ -635,8 +635,8 @@ enum kdbus_make_flags {
  * @kernel_flags:	Supported flags for the used command, kernel → userspace
  * @items:		Items describing details
  *
- * This structure is used with the KDBUS_CMD_BUS_MAKE, KDBUS_CMD_ENDPOINT_MAKE
- * and KDBUS_CMD_DOMAIN_MAKE ioctls.
+ * This structure is used with the KDBUS_CMD_BUS_MAKE and
+ * KDBUS_CMD_ENDPOINT_MAKE ioctls.
  */
 struct kdbus_cmd_make {
 	__u64 size;
@@ -839,8 +839,6 @@ struct kdbus_cmd_match {
  *				name. The bus is immediately shut down and
  *				cleaned up when the opened "control" device node
  *				is closed.
- * KDBUS_CMD_DOMAIN_MAKE:	Similar to KDBUS_CMD_BUS_MAKE, but it creates a
- *				new kdbus domain.
  * KDBUS_CMD_ENDPOINT_MAKE:	Creates a new named special endpoint to talk to
  *				the bus. Such endpoints usually carry a more
  *				restrictive policy and grant restricted access
@@ -887,44 +885,42 @@ struct kdbus_cmd_match {
  */
 #define KDBUS_CMD_BUS_MAKE		_IOW(KDBUS_IOCTL_MAGIC, 0x00,	\
 					     struct kdbus_cmd_make)
-#define KDBUS_CMD_DOMAIN_MAKE		_IOW(KDBUS_IOCTL_MAGIC, 0x10,	\
-					     struct kdbus_cmd_make)
-#define KDBUS_CMD_ENDPOINT_MAKE		_IOW(KDBUS_IOCTL_MAGIC, 0x20,	\
+#define KDBUS_CMD_ENDPOINT_MAKE		_IOW(KDBUS_IOCTL_MAGIC, 0x10,	\
 					     struct kdbus_cmd_make)
 
-#define KDBUS_CMD_HELLO			_IOWR(KDBUS_IOCTL_MAGIC, 0x30,	\
+#define KDBUS_CMD_HELLO			_IOWR(KDBUS_IOCTL_MAGIC, 0x20,	\
 					      struct kdbus_cmd_hello)
-#define KDBUS_CMD_BYEBYE		_IO(KDBUS_IOCTL_MAGIC, 0x31)	\
+#define KDBUS_CMD_BYEBYE		_IO(KDBUS_IOCTL_MAGIC, 0x21)	\
 
-#define KDBUS_CMD_MSG_SEND		_IOWR(KDBUS_IOCTL_MAGIC, 0x40,	\
+#define KDBUS_CMD_MSG_SEND		_IOWR(KDBUS_IOCTL_MAGIC, 0x30,	\
 					      struct kdbus_msg)
-#define KDBUS_CMD_MSG_RECV		_IOWR(KDBUS_IOCTL_MAGIC, 0x41,	\
+#define KDBUS_CMD_MSG_RECV		_IOWR(KDBUS_IOCTL_MAGIC, 0x31,	\
 					      struct kdbus_cmd_recv)
-#define KDBUS_CMD_MSG_CANCEL		_IOW(KDBUS_IOCTL_MAGIC, 0x42,	\
+#define KDBUS_CMD_MSG_CANCEL		_IOW(KDBUS_IOCTL_MAGIC, 0x32,	\
 					     struct kdbus_cmd_cancel)
-#define KDBUS_CMD_FREE			_IOW(KDBUS_IOCTL_MAGIC, 0x43,	\
+#define KDBUS_CMD_FREE			_IOW(KDBUS_IOCTL_MAGIC, 0x33,	\
 					     struct kdbus_cmd_free)
 
-#define KDBUS_CMD_NAME_ACQUIRE		_IOWR(KDBUS_IOCTL_MAGIC, 0x50,	\
+#define KDBUS_CMD_NAME_ACQUIRE		_IOWR(KDBUS_IOCTL_MAGIC, 0x40,	\
 					      struct kdbus_cmd_name)
-#define KDBUS_CMD_NAME_RELEASE		_IOW(KDBUS_IOCTL_MAGIC, 0x51,	\
+#define KDBUS_CMD_NAME_RELEASE		_IOW(KDBUS_IOCTL_MAGIC, 0x41,	\
 					     struct kdbus_cmd_name)
-#define KDBUS_CMD_NAME_LIST		_IOWR(KDBUS_IOCTL_MAGIC, 0x52,	\
+#define KDBUS_CMD_NAME_LIST		_IOWR(KDBUS_IOCTL_MAGIC, 0x42,	\
 					      struct kdbus_cmd_name_list)
 
-#define KDBUS_CMD_CONN_INFO		_IOWR(KDBUS_IOCTL_MAGIC, 0x60,	\
+#define KDBUS_CMD_CONN_INFO		_IOWR(KDBUS_IOCTL_MAGIC, 0x50,	\
 					      struct kdbus_cmd_info)
-#define KDBUS_CMD_CONN_UPDATE		_IOW(KDBUS_IOCTL_MAGIC, 0x61,	\
+#define KDBUS_CMD_CONN_UPDATE		_IOW(KDBUS_IOCTL_MAGIC, 0x51,	\
 					     struct kdbus_cmd_update)
-#define KDBUS_CMD_BUS_CREATOR_INFO	_IOWR(KDBUS_IOCTL_MAGIC, 0x62,	\
+#define KDBUS_CMD_BUS_CREATOR_INFO	_IOWR(KDBUS_IOCTL_MAGIC, 0x52,	\
 					      struct kdbus_cmd_info)
 
-#define KDBUS_CMD_ENDPOINT_UPDATE	_IOW(KDBUS_IOCTL_MAGIC, 0x71,	\
+#define KDBUS_CMD_ENDPOINT_UPDATE	_IOW(KDBUS_IOCTL_MAGIC, 0x61,	\
 					     struct kdbus_cmd_update)
 
-#define KDBUS_CMD_MATCH_ADD		_IOW(KDBUS_IOCTL_MAGIC, 0x80,	\
+#define KDBUS_CMD_MATCH_ADD		_IOW(KDBUS_IOCTL_MAGIC, 0x70,	\
 					     struct kdbus_cmd_match)
-#define KDBUS_CMD_MATCH_REMOVE		_IOW(KDBUS_IOCTL_MAGIC, 0x81,	\
+#define KDBUS_CMD_MATCH_REMOVE		_IOW(KDBUS_IOCTL_MAGIC, 0x71,	\
 					     struct kdbus_cmd_match)
 
 #endif /* _KDBUS_UAPI_H_ */
diff --git a/src/libsystemd/sd-bus/sd-bus.c b/src/libsystemd/sd-bus/sd-bus.c
index e6b47f7fd8..b1a1f79d86 100644
--- a/src/libsystemd/sd-bus/sd-bus.c
+++ b/src/libsystemd/sd-bus/sd-bus.c
@@ -807,7 +807,7 @@ static int parse_container_kernel_address(sd_bus *b, const char **p, char **guid
         machine = NULL;
 
         free(b->kernel);
-        b->kernel = strdup("/dev/kdbus/0-system/bus");
+        b->kernel = strdup("/sys/fs/kdbus/0-system/bus");
         if (!b->kernel)
                 return -ENOMEM;