X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=udev.c;h=67b86e5916ced757a921bbbd442bee3e876c6298;hb=5aebfbcb62614fc2bf2b1579d62e3fe272c6751a;hp=ed42862c00881d195e10012b8ca2dd964501dcfa;hpb=c2f17c9ea8a90d1c12158b947b3f8096404afe33;p=elogind.git

diff --git a/udev.c b/udev.c
index ed42862c0..67b86e591 100644
--- a/udev.c
+++ b/udev.c
@@ -27,6 +27,7 @@
 #include <fcntl.h>
 #include <unistd.h>
 #include <errno.h>
+#include <ctype.h>
 
 #include "udev.h"
 #include "udev_version.h"
@@ -38,14 +39,6 @@
 char **main_argv;
 char **main_envp;
 
-char sysfs_path[SYSFS_PATH_MAX];
-char *udev_config_dir = UDEV_CONFIG_DIR;
-char *udev_root = UDEV_ROOT;
-char udev_db_filename[PATH_MAX+NAME_MAX];
-char udev_config_permission_filename[PATH_MAX+NAME_MAX];
-char udev_config_filename[PATH_MAX+NAME_MAX];
-
-
 static inline char *get_action(void)
 {
 	char *action;
@@ -70,53 +63,60 @@ static inline char *get_seqnum(void)
 	return seqnum;
 }
 
-static void get_dirs(void)
+#ifdef USE_DBUS
+
+/** Global variable for the connection the to system message bus or #NULL
+ *  if we cannot connect or acquire the org.kernel.udev service
+ */
+DBusConnection* sysbus_connection;
+
+/** Disconnect from the system message bus */
+static void sysbus_disconnect()
 {
-	char *temp;
-	char *udev_db = UDEV_DB;
-	char *udev_config = NAMEDEV_CONFIG_FILE;
-	char *udev_permission = NAMEDEV_CONFIG_PERMISSION_FILE;
-	int retval;
-
-	retval = sysfs_get_mnt_path(sysfs_path, SYSFS_PATH_MAX);
-	if (retval)
-		dbg("sysfs_get_mnt_path failed");
-
-	/* see if we should try to override any of the default values */
-	temp = getenv("UDEV_TEST");
-	if (temp != NULL) {
-		/* hm testing is happening, use the specified values, if they are present */
-		temp = getenv("UDEV_SYSFS_PATH");
-		if (temp)
-			strncpy(sysfs_path, temp, sizeof(sysfs_path));
-		temp = getenv("UDEV_CONFIG_DIR");
-		if (temp)
-			udev_config_dir = temp;
-		temp = getenv("UDEV_ROOT");
-		if (temp)
-			udev_root = temp;
-		temp = getenv("UDEV_DB");
-		if (temp)
-			udev_db = temp;
-		temp = getenv("UDEV_CONFIG_FILE");
-		if (temp)
-			udev_config = temp;
-		temp = getenv("UDEV_PERMISSION_FILE");
-		if (temp)
-			udev_permission = temp;
-	}
-	dbg("sysfs_path = %s", sysfs_path);
+        if (sysbus_connection == NULL)
+                return;
 
-	strncpy(udev_db_filename, udev_config_dir, sizeof(udev_db_filename));
-	strncat(udev_db_filename, udev_db, sizeof(udev_db_filename));
+        dbus_connection_disconnect(sysbus_connection);
+        sysbus_connection = NULL;
+}
 
-	strncpy(udev_config_filename, udev_config_dir, sizeof(udev_config_filename));
-	strncat(udev_config_filename, udev_config, sizeof(udev_config_filename));
-	
-	strncpy(udev_config_permission_filename, udev_config_dir, sizeof(udev_config_permission_filename));
-	strncat(udev_config_permission_filename, udev_permission, sizeof(udev_config_permission_filename));
+/** Connect to the system message bus */
+static void sysbus_connect()
+{
+        DBusError error;
+
+        /* Connect to a well-known bus instance, the system bus */
+        dbus_error_init(&error);
+        sysbus_connection = dbus_bus_get(DBUS_BUS_SYSTEM, &error);
+        if (sysbus_connection == NULL) {
+                dbg("cannot connect to system message bus, error %s: %s", 
+                    error.name, error.message);
+                dbus_error_free(&error);
+                return;
+        }
+
+        /*  Acquire the org.kernel.udev service such that listeners
+         *  know that the message is really from us and not from a
+         *  random attacker. See the file udev_sysbus_policy.conf for
+         *  details.
+         *
+         *  Note that a service can have multiple owners (though there
+         *  is a concept of a primary owner for reception of messages)
+         *  so no race is introduced if two copies of udev is running
+         *  at the same time.
+         */
+        dbus_bus_acquire_service(sysbus_connection, "org.kernel.udev", 0, 
+                                 &error);
+        if (dbus_error_is_set(&error)) {
+                printf("cannot acquire org.kernel.udev service, error %s: %s'",
+                       error.name, error.message);
+                sysbus_disconnect();
+                return;
+        }
 }
 
+#endif /* USE_DBUS */
+
 int main(int argc, char **argv, char **envp)
 {
 	char *action;
@@ -141,12 +141,12 @@ int main(int argc, char **argv, char **envp)
 		dbg ("no devpath?");
 		goto exit;
 	}
-	dbg("looking at %s", devpath);
+	dbg("looking at '%s'", devpath);
 
 	/* we only care about class devices and block stuff */
 	if (!strstr(devpath, "class") &&
 	    !strstr(devpath, "block")) {
-		dbg("not block or class");
+		dbg("not a block or class device");
 		goto exit;
 	}
 
@@ -162,11 +162,18 @@ int main(int argc, char **argv, char **envp)
 		goto exit;
 	}
 
+	/* initialize our configuration */
+	udev_init_config();
+
+#ifdef USE_DBUS
+        /* connect to the system message bus */
+        sysbus_connect();
+#endif /* USE_DBUS */
+
 	/* initialize udev database */
-	get_dirs();
 	retval = udevdb_init(UDEVDB_DEFAULT);
 	if (retval != 0) {
-		dbg("Unable to initialize database.");
+		dbg("unable to initialize database");
 		goto exit;
 	}
 
@@ -180,12 +187,16 @@ int main(int argc, char **argv, char **envp)
 		retval = udev_remove_device(devpath, subsystem);
 
 	else {
-		dbg("Unknown action: %s", action);
+		dbg("unknown action '%s'", action);
 		retval = -EINVAL;
 	}
 	udevdb_exit();
 
+#ifdef USE_DBUS
+        /* disconnect from the system message bus */
+        sysbus_disconnect();
+#endif /* USE_DBUS */
+
 exit:	
 	return retval;
 }
-