core: Add kdbus helpers for connections and well known names

src/kdbus.c

@@ -33,8 +33,13 @@
 #include "linux/kdbus.h"
 #include "src/kdbus.h"
 
+#define POOL_SIZE (16 * 1024LU * 1024LU)
+
 static int kdbus_control = -1;
 
+static int kdbus_conn = -1;
+static uint8_t kdbus_id128[16];
+
 bool kdbus_create_bus(void)
 {
 	struct {
@@ -71,7 +76,7 @@ bool kdbus_create_bus(void)
 							"%u-iwd", getuid());
 	bus_make.name_size = 16 + strlen(bus_make.name_param) + 1;
 	bus_make.name_type = KDBUS_ITEM_MAKE_NAME;
-
+	/* bus make head */
 	bus_make.head.size = sizeof(bus_make.head) +
 				bus_make.bloom_size + bus_make.name_size;
 	bus_make.head.flags = KDBUS_MAKE_ACCESS_WORLD;
@@ -93,6 +98,13 @@ bool kdbus_destroy_bus(void)
 	if (kdbus_control < 0)
 		return false;
 
+	if (kdbus_conn >= 0) {
+		l_debug("Closing bus endpoint");
+
+		close(kdbus_conn);
+		kdbus_conn = -1;
+	}
+
 	l_debug("Closing kdbus control interface");
 
 	close(kdbus_control);
@@ -123,3 +135,115 @@ char *kdbus_lookup_bus(void)
 
 	return path;
 }
+
+static bool name_acquire(const char *name)
+{
+	struct {
+		struct kdbus_cmd_name head;
+		char param[64];
+	} cmd_name;
+
+	if (!name)
+		return true;
+
+	memset(&cmd_name, 0, sizeof(cmd_name));
+	/* cmd name head */
+	snprintf(cmd_name.param, sizeof(cmd_name.param), "%s", name);
+	cmd_name.head.size = sizeof(cmd_name.head) + strlen(cmd_name.param) + 1;
+
+	l_debug("Aquiring name %s", cmd_name.param);
+
+	if (ioctl(kdbus_conn, KDBUS_CMD_NAME_ACQUIRE, &cmd_name) < 0) {
+		l_error("Failed to acquire name: %m");
+		return false;
+	}
+
+	return true;
+}
+
+bool kdbus_open_bus(const char *path, const char *name, const char *conn_name)
+{
+	struct {
+		struct kdbus_cmd_hello head;
+		/* conn name item */
+		uint64_t name_size;
+		uint64_t name_type;
+		char name_param[16];
+	} cmd_hello;
+
+	if (kdbus_conn >= 0)
+		return false;
+
+	l_debug("Opening %s", path);
+
+	kdbus_conn = open(path, O_RDWR | O_CLOEXEC);
+	if (kdbus_conn < 0) {
+		l_error("Failed to open bus endpoint: %m");
+		return false;
+	}
+
+	memset(&cmd_hello, 0, sizeof(cmd_hello));
+	/* conn name item */
+	snprintf(cmd_hello.name_param, sizeof(cmd_hello.name_param),
+							"%s", conn_name);
+	cmd_hello.name_size = 16 + strlen(cmd_hello.name_param) + 1;
+	cmd_hello.name_type = KDBUS_ITEM_CONN_NAME;
+	/* cmd hello head */
+	cmd_hello.head.size = sizeof(cmd_hello.head) + cmd_hello.name_size;
+	cmd_hello.head.conn_flags = KDBUS_HELLO_ACCEPT_FD;
+	cmd_hello.head.attach_flags = KDBUS_ATTACH_TIMESTAMP |
+					KDBUS_ATTACH_CREDS |
+					KDBUS_ATTACH_NAMES |
+					KDBUS_ATTACH_COMM |
+					KDBUS_ATTACH_EXE |
+					KDBUS_ATTACH_CMDLINE |
+					KDBUS_ATTACH_CAPS |
+					KDBUS_ATTACH_CGROUP |
+					KDBUS_ATTACH_SECLABEL |
+					KDBUS_ATTACH_AUDIT |
+					KDBUS_ATTACH_CONN_NAME;
+	cmd_hello.head.pool_size = POOL_SIZE;
+
+	l_debug("Sending hello message for %s", cmd_hello.name_param);
+
+	if (ioctl(kdbus_conn, KDBUS_CMD_HELLO, &cmd_hello) < 0) {
+		l_error("Failed to send hello: %m");
+		close(kdbus_conn);
+		kdbus_conn = -1;
+		return false;
+        }
+
+	memcpy(kdbus_id128, cmd_hello.head.id128, sizeof(kdbus_id128));
+
+	l_debug("UUID: %02x%02x%02x%02x-%02x%02x%02x%02x-"
+			"%02x%02x%02x%02x-%02x%02x%02x%02x",
+				kdbus_id128[0],  kdbus_id128[1],
+				kdbus_id128[2],  kdbus_id128[3],
+				kdbus_id128[4],  kdbus_id128[5],
+				kdbus_id128[6],  kdbus_id128[7],
+				kdbus_id128[8],  kdbus_id128[9],
+				kdbus_id128[10], kdbus_id128[11],
+				kdbus_id128[12], kdbus_id128[13],
+				kdbus_id128[14], kdbus_id128[15]);
+
+	if (!name_acquire(name)) {
+		close(kdbus_conn);
+		kdbus_conn = -1;
+		return false;
+	}
+
+	return true;
+};
+
+bool kdbus_close_bus(void)
+{
+	if (kdbus_conn < 0)
+		return false;
+
+	l_debug("Closing bus endpoint");
+
+	close(kdbus_conn);
+	kdbus_conn = -1;
+
+	return true;
+}

src/kdbus.h

@@ -26,3 +26,5 @@ bool kdbus_create_bus(void);
 bool kdbus_destroy_bus(void);
 
 char *kdbus_lookup_bus(void);
+bool kdbus_open_bus(const char *path, const char *name, const char *conn_name);
+bool kdbus_close_bus(void);