zdev: Add support for handling auto-configuration data

Auto-configuration is the name of a new configuration target that is
supported by chzdev and lszdev besides the existing active and
persistent configuration targets. Directives created in this new
configuration are stored as udev rules in the /run/udev/rules.d
directory.

Auto-configuration directives are only in effect if there are no
directives for the same device in the user-provided persistent
configuration. This allows users to override auto-configuration
directives if necessary.

Due to the volatile nature of the /run directory, auto-configuration
directives are cleared on reboot. Therefore mechanisms that generate
auto-configuration directives must recreate them on every boot.

The lszdev tool displays auto-configuration data both in list view
as well as in detail view. Users can specify the new option --auto-conf
to only show data from this configuration target.

Mechanisms that generate automated configuration directives can use
chzdev together with the --auto-conf option to create the corresponding
udev rules.

Note: This change does not include a mechanism that generates
      auto-configuration directives.

Signed-off-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>

zdev/src/export.c

@@ -83,7 +83,7 @@ static bool is_exportable(struct setting *s, config_t config)
 			return true;
 		}
 	}
-	if (SCOPE_PERSISTENT(config)) {
+	if (SCOPE_PERSISTENT(config) || SCOPE_AUTOCONF(config)) {
 		if (setting_is_set(s))
 			return true;
 	}
@@ -148,10 +148,9 @@ static int count_exportable(struct device *dev, config_t config)
 	struct setting *s;
 	int count;
 
-	if (config == config_active)
-		list = dev->active.settings;
-	else
-		list = dev->persistent.settings;
+	list = device_get_setting_list(dev, config);
+	if (!list)
+		return 0;
 	count = 0;
 
 	util_list_iterate(&list->list, s) {
@@ -169,12 +168,26 @@ exit_code_t export_write_device(FILE *fd, struct device *dev, config_t config,
 	exit_code_t rc;
 	struct setting_list *settings;
 
-	if (config == config_all) {
-		rc = export_write_device(fd, dev, config_active, first_ptr);
-		if (rc)
-			return rc;
-		return export_write_device(fd, dev, config_persistent,
-					   first_ptr);
+	if (!SCOPE_SINGLE(config)) {
+		if (SCOPE_ACTIVE(config)) {
+			rc = export_write_device(fd, dev, config_active,
+						 first_ptr);
+			if (rc)
+				return rc;
+		}
+		if (SCOPE_PERSISTENT(config)) {
+			rc = export_write_device(fd, dev, config_persistent,
+						 first_ptr);
+			if (rc)
+				return rc;
+		}
+		if (SCOPE_AUTOCONF(config)) {
+			rc = export_write_device(fd, dev, config_autoconf,
+						 first_ptr);
+			if (rc)
+				return rc;
+		}
+		return EXIT_OK;
 	}
 
 	if (config == config_active) {
@@ -185,10 +198,14 @@ exit_code_t export_write_device(FILE *fd, struct device *dev, config_t config,
 		    !dev->subtype->support_definable)
 			return EXIT_OK;
 		settings = dev->active.settings;
-	} else {
+	} else if (config == config_persistent) {
 		if (!dev->persistent.exists)
 			return EXIT_OK;
 		settings = dev->persistent.settings;
+	} else {
+		if (!dev->autoconf.exists)
+			return EXIT_OK;
+		settings = dev->autoconf.settings;
 	}
 
 	write_header(fd, config, dev->subtype->name, dev->id, first_ptr);
@@ -204,12 +221,21 @@ exit_code_t export_write_devtype(FILE *fd, struct devtype *dt, config_t config,
 	exit_code_t rc;
 	struct setting_list *settings;
 
-	if (config == config_all) {
-		rc = export_write_devtype(fd, dt, config_active, first_ptr);
-		if (rc)
-			return rc;
-		return export_write_devtype(fd, dt, config_persistent,
-					    first_ptr);
+	if (!SCOPE_SINGLE(config)) {
+		if (SCOPE_ACTIVE(config)) {
+			rc = export_write_devtype(fd, dt, config_active,
+						  first_ptr);
+			if (rc)
+				return rc;
+		}
+		if (SCOPE_PERSISTENT(config)) {
+			rc = export_write_devtype(fd, dt, config_persistent,
+						  first_ptr);
+			if (rc)
+				return rc;
+		}
+		/* Scope autoconf not supported for devtype */
+		return EXIT_OK;
 	}
 
 	if (config == config_active)
@@ -379,6 +405,10 @@ static exit_code_t handle_header(const char *filename, int lineno,
 			setting_list_clear(dev->persistent.settings);
 			dev->persistent.exists = 1;
 		}
+		if (SCOPE_AUTOCONF(hdr->config)) {
+			setting_list_clear(dev->autoconf.settings);
+			dev->autoconf.exists = 1;
+		}
 	}
 
 out:
@@ -397,13 +427,26 @@ static exit_code_t handle_setting(const char *filename, int lineno,
 	struct attrib **attribs, *a;
 	struct setting_list *list;
 
-	if (config == config_all) {
-		rc = handle_setting(filename, lineno, key, value, dt, dev,
-				    config_active);
-		if (rc)
-			return rc;
-		return handle_setting(filename, lineno, key, value, dt, dev,
-				      config_persistent);
+	if (!SCOPE_SINGLE(config)) {
+		if (SCOPE_ACTIVE(config)) {
+			rc = handle_setting(filename, lineno, key, value, dt,
+					    dev, config_active);
+			if (rc)
+				return rc;
+		}
+		if (SCOPE_PERSISTENT(config)) {
+			rc = handle_setting(filename, lineno, key, value, dt,
+					    dev, config_persistent);
+			if (rc)
+				return rc;
+		}
+		if (SCOPE_AUTOCONF(config)) {
+			rc = handle_setting(filename, lineno, key, value, dt,
+					    dev, config_autoconf);
+			if (rc)
+				return rc;
+		}
+		return EXIT_OK;
 	}
 
 	if (dt) {
@@ -452,7 +495,8 @@ static bool empty_device(struct device *dev)
 	if (dev->subtype->support_definable)
 		return false;
 	if (util_list_is_empty(&dev->active.settings->list) &&
-	    util_list_is_empty(&dev->persistent.settings->list))
+	    util_list_is_empty(&dev->persistent.settings->list) &&
+	    util_list_is_empty(&dev->autoconf.settings->list))
 		return true;
 	return false;
 }