libudev: enumerate - accept list of subsystems to scan, or skip

TODO

@@ -1,13 +1,12 @@
-  o enumerate() - add buses and drivers
+  o libudev enumerate
+      add buses and drivers
+      add /sys/block/ scanning crap
       use enumerate for "trigger"
-
-  o add libudev interface for /dev/.udev/queue/ state
+  o libudev queue - interface for /dev/.udev/queue/ state
       use queue interface for "settle"
-
-  o use libudev in udev_rules.c
+  o use libudev device in udev_rules.c
       get rid of udevice, store rule matching state in rule iterator
   o rework rules to a match-action list, instead of a rules array
-
   o add DVB variables to kernel, and drop shell script rule
   o add watershed extra
   o log warning if the kernel uses CONFIG_SYSFS_DEPRECATED*=y,

udev/lib/exported_symbols

@@ -10,6 +10,7 @@ udev_set_userdata
 udev_get_sys_path
 udev_get_dev_path
 udev_list_entry_get_next
+udev_list_entry_get_by_name
 udev_list_entry_get_name
 udev_list_entry_get_value
 udev_device_new_from_syspath
@@ -30,9 +31,11 @@ udev_device_get_driver
 udev_device_get_devnum
 udev_device_get_seqnum
 udev_device_get_attr_value
+udev_enumerate_new_from_devices
 udev_enumerate_new_from_subsystems
 udev_enumerate_ref
 udev_enumerate_unref
+udev_enumerate_get_udev
 udev_enumerate_get_list_entry
 udev_monitor_new_from_socket
 udev_monitor_new_from_netlink

udev/lib/libudev-device.c

@@ -252,7 +252,7 @@ struct udev_device *udev_device_new_from_syspath(struct udev *udev, const char *
 	subdir = &syspath[len+1];
 	pos = strrchr(subdir, '/');
 	if (pos == NULL || pos < &subdir[2]) {
-		info(udev, "not in subdir :%s\n", syspath);
+		info(udev, "not a subdir :%s\n", syspath);
 		return NULL;
 	}
 
@@ -312,8 +312,11 @@ struct udev_device *udev_device_new_from_devnum(struct udev *udev, char type, de
 	if (util_resolve_sys_link(udev, path, sizeof(path)) == 0)
 		return udev_device_new_from_syspath(udev, path);
 
-	/* fallback to search all sys devices for the major/minor */
-	enumerate = udev_enumerate_new_from_subsystems(udev, NULL);
+	/* fallback to search sys devices for the major/minor */
+	if (type == 'b')
+		enumerate = udev_enumerate_new_from_devices(udev, "block", NULL);
+	else if (type == 'c')
+		enumerate = udev_enumerate_new_from_devices(udev, "!block", NULL);
 	if (enumerate == NULL)
 		return NULL;
 	udev_list_entry_foreach(list_entry, udev_enumerate_get_list_entry(enumerate)) {
@@ -322,6 +325,13 @@ struct udev_device *udev_device_new_from_devnum(struct udev *udev, char type, de
 		device_loop = udev_device_new_from_syspath(udev, udev_list_entry_get_name(list_entry));
 		if (device_loop != NULL) {
 			if (udev_device_get_devnum(device_loop) == devnum) {
+				const char *subsystem;
+
+				subsystem = udev_device_get_subsystem(device_loop);
+				if (type == 'b' && strcmp(subsystem, "block") != 0)
+					continue;
+				if (type == 'c' && strcmp(subsystem, "block") == 0)
+					continue;
 				device = device_loop;
 				break;
 			}

udev/lib/libudev-enumerate.c

@@ -54,6 +54,13 @@ void udev_enumerate_unref(struct udev_enumerate *udev_enumerate)
 	free(udev_enumerate);
 }
 
+struct udev *udev_enumerate_get_udev(struct udev_enumerate *udev_enumerate)
+{
+	if (udev_enumerate == NULL)
+		return NULL;
+	return udev_enumerate->udev;
+}
+
 struct udev_list_entry *udev_enumerate_get_list_entry(struct udev_enumerate *udev_enumerate)
 {
 	if (udev_enumerate == NULL)
@@ -63,7 +70,7 @@ struct udev_list_entry *udev_enumerate_get_list_entry(struct udev_enumerate *ude
 
 static int devices_scan_subsystem(struct udev *udev,
 				  const char *basedir, const char *subsystem, const char *subdir,
-				  struct list_node *device_list)
+				  struct list_node *devices_list)
 {
 	char path[UTIL_PATH_SIZE];
 	DIR *dir;
@@ -87,34 +94,44 @@ static int devices_scan_subsystem(struct udev *udev,
 		util_strlcat(syspath, "/", sizeof(syspath));
 		util_strlcat(syspath, dent->d_name, sizeof(syspath));
 		util_resolve_sys_link(udev, syspath, sizeof(syspath));
-		list_entry_add(udev, device_list, syspath, NULL, 1, 1);
+		list_entry_add(udev, devices_list, syspath, NULL, 1, 1);
 	}
 	closedir(dir);
 	return 0;
 }
 
 static int devices_scan_subsystems(struct udev *udev,
-				   const char *basedir, const char *subsystem, const char *subdir,
-				   struct list_node *device_list)
+				   const char *basedir, const char *subdir,
+				   struct udev_list_entry *subsystem_include_list,
+				   struct udev_list_entry *subsystem_exclude_list,
+				   struct list_node *devices_list)
 {
-	char path[UTIL_PATH_SIZE];
-	DIR *dir;
-	struct dirent *dent;
+	if (subsystem_include_list != NULL) {
+		struct udev_list_entry *list_entry;
 
-	if (subsystem != NULL)
-		return devices_scan_subsystem(udev, basedir, subsystem, subdir, device_list);
+		/* if list of subsystems to scan is given, just use this list */
+		udev_list_entry_foreach(list_entry, subsystem_include_list)
+			devices_scan_subsystem(udev, basedir, udev_list_entry_get_name(list_entry), subdir, devices_list);
+	} else {
+		char path[UTIL_PATH_SIZE];
+		DIR *dir;
+		struct dirent *dent;
 
-	util_strlcpy(path, udev_get_sys_path(udev), sizeof(path));
-	util_strlcat(path, basedir, sizeof(path));
-	dir = opendir(path);
-	if (dir == NULL)
-		return -1;
-	for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
-		if (dent->d_name[0] == '.')
-			continue;
-		devices_scan_subsystem(udev, basedir, dent->d_name, subdir, device_list);
+		/* if no list of subsystems to scan is given, scan all, and possible exclude some subsystems */
+		util_strlcpy(path, udev_get_sys_path(udev), sizeof(path));
+		util_strlcat(path, basedir, sizeof(path));
+		dir = opendir(path);
+		if (dir == NULL)
+			return -1;
+		for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
+			if (dent->d_name[0] == '.')
+				continue;
+			if (udev_list_entry_get_by_name(subsystem_exclude_list, dent->d_name) != NULL)
+					continue;
+			devices_scan_subsystem(udev, basedir, dent->d_name, subdir, devices_list);
+		}
+		closedir(dir);
 	}
-	closedir(dir);
 	return 0;
 }
 
@@ -140,17 +157,21 @@ static int devices_delay(struct udev *udev, const char *syspath)
 }
 
 /**
- * udev_enumerate_new_from_subsystems:
+ * udev_enumerate_new_from_devices:
  * @udev: udev library context
- * @subsystem: the subsystem to enumerate
+ * @subsystem: the list of names of subsystems to look for devices
  *
  * Returns: an enumeration context
  **/
-struct udev_enumerate *udev_enumerate_new_from_subsystems(struct udev *udev, const char *subsystem)
+struct udev_enumerate *udev_enumerate_new_from_devices(struct udev *udev, const char *subsystem, ...)
 {
 	struct udev_enumerate *udev_enumerate;
+	va_list vargs;
+	const char *arg;
 	char base[UTIL_PATH_SIZE];
 	struct stat statbuf;
+	struct list_node subsystem_include_list;
+	struct list_node subsystem_exclude_list;
 	struct udev_list_entry *list_entry;
 
 	if (udev == NULL)
@@ -164,19 +185,42 @@ struct udev_enumerate *udev_enumerate_new_from_subsystems(struct udev *udev, con
 	udev_enumerate->udev = udev;
 	list_init(&udev_enumerate->devices_list);
 
+	va_start(vargs, subsystem);
+	list_init(&subsystem_include_list);
+	list_init(&subsystem_exclude_list);
+	for (arg = subsystem; arg != NULL; arg = va_arg(vargs, const char *)) {
+		if (arg[0] != '!')
+			list_entry_add(udev, &subsystem_include_list, arg, NULL, 1, 0);
+		else
+			list_entry_add(udev, &subsystem_exclude_list, &arg[1], NULL, 1, 0);
+	}
+	va_end(vargs);
+
 	/* if we have /sys/subsystem/, forget all the old stuff */
 	util_strlcpy(base, udev_get_sys_path(udev), sizeof(base));
 	util_strlcat(base, "/subsystem", sizeof(base));
 	if (stat(base, &statbuf) == 0) {
 		info(udev, "searching 'subsystem/*/devices/*' dir\n");
-		devices_scan_subsystems(udev, "/subsystem", subsystem, "/devices", &udev_enumerate->devices_list);
+		devices_scan_subsystems(udev, "/subsystem", "/devices",
+					list_get_entry(&subsystem_include_list),
+					list_get_entry(&subsystem_exclude_list),
+					&udev_enumerate->devices_list);
 	} else {
 		info(udev, "searching 'bus/*/devices/*' dir\n");
-		devices_scan_subsystems(udev, "/bus", subsystem, "/devices", &udev_enumerate->devices_list);
+		devices_scan_subsystems(udev, "/bus", "/devices",
+					list_get_entry(&subsystem_include_list),
+					list_get_entry(&subsystem_exclude_list),
+					&udev_enumerate->devices_list);
 		info(udev, "searching 'class/*' dir\n");
-		devices_scan_subsystems(udev, "/class", subsystem, NULL, &udev_enumerate->devices_list);
+		devices_scan_subsystems(udev, "/class", NULL,
+					list_get_entry(&subsystem_include_list),
+					list_get_entry(&subsystem_exclude_list),
+					&udev_enumerate->devices_list);
 	}
 
+	list_cleanup(udev, &subsystem_include_list);
+	list_cleanup(udev, &subsystem_exclude_list);
+
 	/* sort delayed devices to the end of the list */
 	udev_list_entry_foreach(list_entry, list_get_entry(&udev_enumerate->devices_list)) {
 		if (devices_delay(udev, udev_list_entry_get_name(list_entry)))
@@ -184,3 +228,8 @@ struct udev_enumerate *udev_enumerate_new_from_subsystems(struct udev *udev, con
 	}
 	return udev_enumerate;
 }
+
+struct udev_enumerate *udev_enumerate_new_from_subsystems(struct udev *udev)
+{
+	return NULL;
+}

udev/lib/libudev-list.c

@@ -192,6 +192,16 @@ struct udev_list_entry *udev_list_entry_get_next(struct udev_list_entry *list_en
 	return list_node_to_entry(next);
 }
 
+struct udev_list_entry *udev_list_entry_get_by_name(struct udev_list_entry *list_entry, const char *name)
+{
+	struct udev_list_entry *entry;
+
+	udev_list_entry_foreach(entry, list_entry)
+		if (strcmp(udev_list_entry_get_name(entry), name) == 0)
+			return entry;
+	return NULL;
+}
+
 const char *udev_list_entry_get_name(struct udev_list_entry *list_entry)
 {
 	if (list_entry == NULL)

udev/lib/libudev.h

@@ -52,6 +52,7 @@ extern void udev_selinux_lsetfilecon(struct udev *udev, const char *file, unsign
 /* list iteration */
 struct udev_list_entry;
 extern struct udev_list_entry *udev_list_entry_get_next(struct udev_list_entry *list_entry);
+extern struct udev_list_entry *udev_list_entry_get_by_name(struct udev_list_entry *list_entry, const char *name);
 extern const char *udev_list_entry_get_name(struct udev_list_entry *list_entry);
 extern const char *udev_list_entry_get_value(struct udev_list_entry *list_entry);
 #define udev_list_entry_foreach(entry, first) \
@@ -93,8 +94,10 @@ extern struct udev_device *udev_monitor_receive_device(struct udev_monitor *udev
 
 /* sys enumeration */
 struct udev_enumerate;
-extern struct udev_enumerate *udev_enumerate_new_from_subsystems(struct udev *udev, const char *subsystem);
+extern struct udev_enumerate *udev_enumerate_new_from_devices(struct udev *udev, const char *subsystem, ...);
+extern struct udev_enumerate *udev_enumerate_new_from_subsystems(struct udev *udev);
 extern struct udev_enumerate *udev_enumerate_ref(struct udev_enumerate *udev_enumerate);
+extern struct udev *udev_enumerate_get_udev(struct udev_enumerate *udev_enumerate);
 extern void udev_enumerate_unref(struct udev_enumerate *udev_enumerate);
 extern struct udev_list_entry *udev_enumerate_get_list_entry(struct udev_enumerate *udev_enumerate);
 

udev/lib/test-libudev.c

@@ -157,20 +157,16 @@ static int test_device_devnum(struct udev *udev)
 	return 0;
 }
 
-static int test_enumerate(struct udev *udev, const char *subsystem)
+static int test_enumerate_print_list(struct udev_enumerate *enumerate)
 {
-	struct udev_enumerate *enumerate;
 	struct udev_list_entry *list_entry;
 	int count = 0;
 
-	enumerate = udev_enumerate_new_from_subsystems(udev, NULL);
-	if (enumerate == NULL)
-		return -1;
-	list_entry = udev_enumerate_get_list_entry(enumerate);
-	while (list_entry != NULL) {
+	udev_list_entry_foreach(list_entry, udev_enumerate_get_list_entry(enumerate)) {
 		struct udev_device *device;
 
-		device = udev_device_new_from_syspath(udev, udev_list_entry_get_name(list_entry));
+		device = udev_device_new_from_syspath(udev_enumerate_get_udev(enumerate),
+						      udev_list_entry_get_name(list_entry));
 		if (device != NULL) {
 			printf("device:    '%s' (%s) '%s'\n",
 			       udev_device_get_syspath(device),
@@ -179,9 +175,7 @@ static int test_enumerate(struct udev *udev, const char *subsystem)
 			udev_device_unref(device);
 			count++;
 		}
-		list_entry = udev_list_entry_get_next(list_entry);
 	}
-	udev_enumerate_unref(enumerate);
 	printf("found %i devices\n\n", count);
 	return count;
 }
@@ -248,6 +242,7 @@ int main(int argc, char *argv[], char *envp[])
 		{ "version", 0, NULL, 'V' },
 		{}
 	};
+	struct udev_enumerate *enumerate;
 	const char *syspath = "/devices/virtual/mem/null";
 	const char *subsystem = NULL;
 	const char *socket = "@/org/kernel/udev/monitor";
@@ -309,7 +304,35 @@ int main(int argc, char *argv[], char *envp[])
 	test_device(udev, syspath);
 	test_device_devnum(udev);
 	test_device_parents(udev, syspath);
-	test_enumerate(udev, subsystem);
+
+	printf("enumerate '%s'\n", subsystem == NULL ? "<all>" : subsystem);
+	enumerate = udev_enumerate_new_from_devices(udev, subsystem, NULL);
+	if (enumerate == NULL)
+		return -1;
+	test_enumerate_print_list(enumerate);
+	udev_enumerate_unref(enumerate);
+
+	printf("enumerate 'block'\n");
+	enumerate = udev_enumerate_new_from_devices(udev, "block", NULL);
+	if (enumerate == NULL)
+		return -1;
+	test_enumerate_print_list(enumerate);
+	udev_enumerate_unref(enumerate);
+
+	printf("enumerate '!block'\n");
+	enumerate = udev_enumerate_new_from_devices(udev, "!block", NULL);
+	if (enumerate == NULL)
+		return -1;
+	test_enumerate_print_list(enumerate);
+	udev_enumerate_unref(enumerate);
+
+	printf("enumerate 'pci, mem, vc'\n");
+	enumerate = udev_enumerate_new_from_devices(udev, "pci", "mem", "vc", NULL);
+	if (enumerate == NULL)
+		return -1;
+	test_enumerate_print_list(enumerate);
+	udev_enumerate_unref(enumerate);
+
 	test_monitor(udev, socket);
 out:
 	udev_unref(udev);

udev/udevadm-info.c

@@ -186,7 +186,7 @@ static int export_devices(struct udev *udev)
 	struct udev_enumerate *enumerate;
 	struct udev_list_entry *list_entry;
 
-	enumerate = udev_enumerate_new_from_subsystems(udev, NULL);
+	enumerate = udev_enumerate_new_from_devices(udev, NULL);
 	if (enumerate == NULL)
 		return -1;
 	udev_list_entry_foreach(list_entry, udev_enumerate_get_list_entry(enumerate)) {
@@ -301,7 +301,7 @@ int udevadm_info(struct udev *udev, int argc, char *argv[])
 				rc = 2;
 				goto exit;
 			}
-			/* add /sys if needed */
+			/* add sys dir if needed */
 			if (strncmp(optarg, udev_get_sys_path(udev), strlen(udev_get_sys_path(udev))) != 0) {
 				util_strlcpy(path, udev_get_sys_path(udev), sizeof(path));
 				util_strlcat(path, optarg, sizeof(path));