X-Git-Url: http://git.ozlabs.org/?p=petitboot;a=blobdiff_plain;f=discover%2Fdevice-handler.c;h=5df070073b4d298c8a49a5488010434b73ff4f32;hp=ccc7cc3d01dc8ce0d5fa01f5dc885042461af0dc;hb=f155a58a64c660e46e74123293482561b816a39a;hpb=51c6aaf7864eb65779d548ee2549caa357f71e2c

diff --git a/discover/device-handler.c b/discover/device-handler.c
index ccc7cc3..5df0700 100644
--- a/discover/device-handler.c
+++ b/discover/device-handler.c
@@ -1,13 +1,15 @@
-
 #include <assert.h>
 #include <stdlib.h>
+#include <stdbool.h>
 #include <unistd.h>
 #include <string.h>
 #include <errno.h>
+#include <mntent.h>
+#include <locale.h>
 #include <sys/stat.h>
 #include <sys/wait.h>
+#include <sys/mount.h>
 
-#include <pb-config/pb-config.h>
 #include <talloc/talloc.h>
 #include <list/list.h>
 #include <log/log.h>
@@ -15,32 +17,71 @@
 #include <system/system.h>
 #include <process/process.h>
 #include <url/url.h>
+#include <i18n/i18n.h>
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netdb.h>
+#include <arpa/inet.h>
 
 #include "device-handler.h"
 #include "discover-server.h"
+#include "devmapper.h"
+#include "user-event.h"
+#include "platform.h"
 #include "event.h"
 #include "parser.h"
 #include "resource.h"
-#include "udev.h"
 #include "paths.h"
+#include "sysinfo.h"
 #include "boot.h"
+#include "udev.h"
+#include "network.h"
+#include "ipmi.h"
+
+enum default_priority {
+	DEFAULT_PRIORITY_REMOTE		= 1,
+	DEFAULT_PRIORITY_LOCAL_FIRST	= 2,
+	DEFAULT_PRIORITY_LOCAL_LAST	= 0xfe,
+	DEFAULT_PRIORITY_DISABLED	= 0xff,
+};
 
 struct device_handler {
 	struct discover_server	*server;
 	int			dry_run;
 
+	struct pb_udev		*udev;
+	struct network		*network;
+	struct user_event	*user_event;
+
 	struct discover_device	**devices;
 	unsigned int		n_devices;
 
+	struct ramdisk_device	**ramdisks;
+	unsigned int		n_ramdisks;
+
 	struct waitset		*waitset;
 	struct waiter		*timeout_waiter;
 	bool			autoboot_enabled;
 	unsigned int		sec_to_boot;
 
 	struct discover_boot_option *default_boot_option;
+	int			default_boot_option_priority;
+
 	struct list		unresolved_boot_options;
+
+	struct boot_task	*pending_boot;
+	bool			pending_boot_is_default;
 };
 
+static int mount_device(struct discover_device *dev);
+static int umount_device(struct discover_device *dev);
+
+static int device_handler_init_sources(struct device_handler *handler);
+static void device_handler_reinit_sources(struct device_handler *handler);
+
+static void device_handler_update_lang(const char *lang);
+
 void discover_context_add_boot_option(struct discover_context *ctx,
 		struct discover_boot_option *boot_option)
 {
@@ -86,11 +127,6 @@ struct discover_boot_option *discover_boot_option_create(
 	return opt;
 }
 
-static int device_match_path(struct discover_device *dev, const char *path)
-{
-	return dev->device_path && !strcmp(dev->device_path, path);
-}
-
 static int device_match_uuid(struct discover_device *dev, const char *uuid)
 {
 	return dev->uuid && !strcmp(dev->uuid, uuid);
@@ -106,6 +142,12 @@ static int device_match_id(struct discover_device *dev, const char *id)
 	return !strcmp(dev->device->id, id);
 }
 
+static int device_match_serial(struct discover_device *dev, const char *serial)
+{
+	const char *val = discover_device_get_param(dev, "ID_SERIAL");
+	return val && !strcmp(val, serial);
+}
+
 static struct discover_device *device_lookup(
 		struct device_handler *device_handler,
 		int (match_fn)(struct discover_device *, const char *),
@@ -130,26 +172,10 @@ static struct discover_device *device_lookup(
 struct discover_device *device_lookup_by_name(struct device_handler *handler,
 		const char *name)
 {
-	struct discover_device *dev;
-	char *path;
-
-	if (strncmp(name, "/dev/", strlen("/dev/")))
-		path = talloc_asprintf(NULL, "/dev/%s", name);
-	else
-		path = talloc_strdup(NULL, name);
-
-	dev = device_lookup_by_path(handler, path);
-
-	talloc_free(path);
-
-	return dev;
-}
+	if (!strncmp(name, "/dev/", strlen("/dev/")))
+		name += strlen("/dev/");
 
-struct discover_device *device_lookup_by_path(
-		struct device_handler *device_handler,
-		const char *path)
-{
-	return device_lookup(device_handler, device_match_path, path);
+	return device_lookup_by_id(handler, name);
 }
 
 struct discover_device *device_lookup_by_uuid(
@@ -173,103 +199,108 @@ struct discover_device *device_lookup_by_id(
 	return device_lookup(device_handler, device_match_id, id);
 }
 
+struct discover_device *device_lookup_by_serial(
+		struct device_handler *device_handler,
+		const char *serial)
+{
+	return device_lookup(device_handler, device_match_serial, serial);
+}
+
 void device_handler_destroy(struct device_handler *handler)
 {
 	talloc_free(handler);
 }
 
-#ifdef PETITBOOT_TEST
-
-/* we have a simplified interface for petitboot testing, but still want
- * to keep struct device_handler opaque. */
-struct device_handler *device_handler_init(
-		struct discover_server *server __attribute__((unused)),
-		struct waitset *waitset __attribute__((unused)),
-		int dry_run __attribute__((unused)))
+static int destroy_device(void *arg)
 {
-	struct device_handler *handler;
+	struct discover_device *dev = arg;
 
-	handler = talloc_zero(NULL, struct device_handler);
-	list_init(&handler->unresolved_boot_options);
+	umount_device(dev);
 
-	return handler;
+	return 0;
 }
 
-void device_handler_add_device(struct device_handler *handler,
-		struct discover_device *dev)
+struct discover_device *discover_device_create(struct device_handler *handler,
+		const char *id)
 {
-	handler->n_devices++;
-	handler->devices = talloc_realloc(handler, handler->devices,
-		struct discover_device *, handler->n_devices);
-	handler->devices[handler->n_devices - 1] = dev;
-}
-
-#else
+	struct discover_device *dev;
 
-static int mount_device(struct discover_device *dev)
-{
-	int rc;
+	dev = device_lookup_by_id(handler, id);
+	if (dev)
+		return dev;
 
-	if (!dev->device_path)
-		return -1;
+	dev = talloc_zero(handler, struct discover_device);
+	dev->device = talloc_zero(dev, struct device);
+	dev->device->id = talloc_strdup(dev->device, id);
+	list_init(&dev->params);
+	list_init(&dev->boot_options);
 
-	if (!dev->mount_path)
-		dev->mount_path = join_paths(dev, mount_base(),
-						dev->device_path);
+	talloc_set_destructor(dev, destroy_device);
 
-	if (pb_mkdir_recursive(dev->mount_path))
-		pb_log("couldn't create mount directory %s: %s\n",
-				dev->mount_path, strerror(errno));
+	return dev;
+}
 
-	rc = process_run_simple(dev, pb_system_apps.mount,
-			dev->device_path, dev->mount_path,
-			"-o", "ro", NULL);
+struct discover_device_param {
+	char			*name;
+	char			*value;
+	struct list_item	list;
+};
 
-	if (!rc)
-		return 0;
+void discover_device_set_param(struct discover_device *device,
+		const char *name, const char *value)
+{
+	struct discover_device_param *param;
+	bool found = false;
 
-	/* Retry mount without ro option. */
-	rc = process_run_simple(dev, pb_system_apps.mount,
-			dev->device_path, dev->mount_path, NULL);
+	list_for_each_entry(&device->params, param, list) {
+		if (!strcmp(param->name, name)) {
+			found = true;
+			break;
+		}
+	}
 
-	if (!rc)
-		return 0;
+	if (!found) {
+		if (!value)
+			return;
+		param = talloc(device, struct discover_device_param);
+		param->name = talloc_strdup(param, name);
+		list_add(&device->params, &param->list);
+	} else {
+		if (!value) {
+			list_remove(&param->list);
+			talloc_free(param);
+			return;
+		}
+		talloc_free(param->value);
+	}
 
-	pb_rmdir_recursive(mount_base(), dev->mount_path);
-	return -1;
+	param->value = talloc_strdup(param, value);
 }
 
-static int umount_device(struct discover_device *dev)
+const char *discover_device_get_param(struct discover_device *device,
+		const char *name)
 {
-	int status;
-
-	if (!dev->mount_path)
-		return 0;
-
-	status = process_run_simple(dev, pb_system_apps.umount,
-			dev->mount_path, NULL);
-
-	if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
-		return -1;
+	struct discover_device_param *param;
 
-	pb_rmdir_recursive(mount_base(), dev->mount_path);
-
-	return 0;
+	list_for_each_entry(&device->params, param, list) {
+		if (!strcmp(param->name, name))
+			return param->value;
+	}
+	return NULL;
 }
 
 struct device_handler *device_handler_init(struct discover_server *server,
 		struct waitset *waitset, int dry_run)
 {
 	struct device_handler *handler;
+	int rc;
 
-	handler = talloc(NULL, struct device_handler);
-	handler->devices = NULL;
-	handler->n_devices = 0;
+	handler = talloc_zero(NULL, struct device_handler);
 	handler->server = server;
 	handler->waitset = waitset;
 	handler->dry_run = dry_run;
-	handler->default_boot_option = NULL;
 	handler->autoboot_enabled = config_get()->autoboot_enabled;
+
 	list_init(&handler->unresolved_boot_options);
 
 	/* set up our mount point base */
@@ -277,67 +308,55 @@ struct device_handler *device_handler_init(struct discover_server *server,
 
 	parser_init();
 
-	return handler;
-}
-
-static int destroy_device(void *arg)
-{
-	struct discover_device *dev = arg;
-
-	umount_device(dev);
-
-	return 0;
-}
-
-static struct discover_device *find_device(struct device_handler *handler,
-		const char *id)
-{
-	struct discover_device *dev;
-	unsigned int i;
+	if (config_get()->safe_mode)
+		return handler;
 
-	for (i = 0; i < handler->n_devices; i++) {
-		dev = handler->devices[i];
-		if (!strcmp(dev->device->id, id))
-			return dev;
+	rc = device_handler_init_sources(handler);
+	if (rc) {
+		talloc_free(handler);
+		return NULL;
 	}
 
-	return NULL;
+	return handler;
 }
 
-static struct discover_device *discover_device_create(
-		struct device_handler *handler,
-		struct discover_context *ctx,
-		struct event *event)
+void device_handler_reinit(struct device_handler *handler)
 {
-	struct discover_device *dev;
-	const char *devname;
-
-	dev = find_device(handler, event->device);
-	if (dev)
-		return dev;
+	struct discover_boot_option *opt, *tmp;
+	struct ramdisk_device *ramdisk;
+	unsigned int i;
 
-	dev = talloc_zero(ctx, struct discover_device);
-	dev->device = talloc_zero(dev, struct device);
-	list_init(&dev->boot_options);
+	device_handler_cancel_default(handler);
 
-	devname = event_get_param(ctx->event, "DEVNAME");
-	if (devname)
-		dev->device_path = talloc_strdup(dev, devname);
+	/* free unresolved boot options */
+	list_for_each_entry_safe(&handler->unresolved_boot_options,
+			opt, tmp, list)
+		talloc_free(opt);
+	list_init(&handler->unresolved_boot_options);
 
-	dev->device->id = talloc_strdup(dev, event->device);
+	/* drop all devices */
+	for (i = 0; i < handler->n_devices; i++) {
+		discover_server_notify_device_remove(handler->server,
+				handler->devices[i]->device);
+		ramdisk = handler->devices[i]->ramdisk;
+		talloc_free(handler->devices[i]);
+		talloc_free(ramdisk);
+	}
 
-	talloc_set_destructor(dev, destroy_device);
+	talloc_free(handler->devices);
+	handler->devices = NULL;
+	handler->n_devices = 0;
+	talloc_free(handler->ramdisks);
+	handler->ramdisks = NULL;
+	handler->n_ramdisks = 0;
 
-	return dev;
+	device_handler_reinit_sources(handler);
 }
 
-/**
- * device_handler_remove - Remove a device from the handler device array.
- */
-
-static void device_handler_remove(struct device_handler *handler,
-	struct discover_device *device)
+void device_handler_remove(struct device_handler *handler,
+		struct discover_device *device)
 {
+	struct discover_boot_option *opt, *tmp;
 	unsigned int i;
 
 	for (i = 0; i < handler->n_devices; i++)
@@ -345,17 +364,34 @@ static void device_handler_remove(struct device_handler *handler,
 			break;
 
 	if (i == handler->n_devices) {
-		assert(0 && "unknown device");
+		talloc_free(device);
 		return;
 	}
 
+	/* Free any unresolved options, as they're currently allocated
+	 * against the handler */
+	list_for_each_entry_safe(&handler->unresolved_boot_options,
+			opt, tmp, list) {
+		if (opt->device != device)
+			continue;
+		list_remove(&opt->list);
+		talloc_free(opt);
+	}
+
+	/* if this is a network device, we have to unregister it from the
+	 * network code */
+	if (device->device->type == DEVICE_TYPE_NETWORK)
+		network_unregister_device(handler->network, device);
+
 	handler->n_devices--;
 	memmove(&handler->devices[i], &handler->devices[i + 1],
 		(handler->n_devices - i) * sizeof(handler->devices[0]));
 	handler->devices = talloc_realloc(handler, handler->devices,
 		struct discover_device *, handler->n_devices);
 
-	discover_server_notify_device_remove(handler->server, device->device);
+	if (device->notified)
+		discover_server_notify_device_remove(handler->server,
+							device->device);
 
 	talloc_free(device);
 }
@@ -376,7 +412,7 @@ static void countdown_status(struct device_handler *handler,
 	status.progress = -1;
 	status.detail = NULL;
 	status.message = talloc_asprintf(handler,
-			"Booting %s in %u sec", opt->option->name, sec);
+			_("Booting in %d sec: %s"), sec, opt->option->name);
 
 	discover_server_notify_boot_status(handler->server, &status);
 
@@ -391,6 +427,9 @@ static int default_timeout(void *arg)
 	if (!handler->default_boot_option)
 		return 0;
 
+	if (handler->pending_boot)
+		return 0;
+
 	opt = handler->default_boot_option;
 
 	if (handler->sec_to_boot) {
@@ -402,26 +441,148 @@ static int default_timeout(void *arg)
 		return 0;
 	}
 
+	handler->timeout_waiter = NULL;
+
 	pb_log("Timeout expired, booting default option %s\n", opt->option->id);
 
-	boot(handler, handler->default_boot_option, NULL,
-			handler->dry_run, boot_status, handler);
+	handler->pending_boot = boot(handler, handler->default_boot_option,
+			NULL, handler->dry_run, boot_status, handler);
+	handler->pending_boot_is_default = true;
 	return 0;
 }
 
+struct {
+	enum ipmi_bootdev	ipmi_type;
+	enum device_type	device_type;
+} device_type_map[] = {
+	{ IPMI_BOOTDEV_NETWORK, DEVICE_TYPE_NETWORK },
+	{ IPMI_BOOTDEV_DISK, DEVICE_TYPE_DISK },
+	{ IPMI_BOOTDEV_DISK, DEVICE_TYPE_USB },
+	{ IPMI_BOOTDEV_CDROM, DEVICE_TYPE_OPTICAL },
+};
+
+static bool ipmi_device_type_matches(enum ipmi_bootdev ipmi_type,
+		enum device_type device_type)
+{
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(device_type_map); i++) {
+		if (device_type_map[i].device_type == device_type)
+			return device_type_map[i].ipmi_type == ipmi_type;
+	}
+
+	return false;
+}
+
+static int autoboot_option_priority(const struct config *config,
+				struct discover_boot_option *opt)
+{
+	enum device_type type = opt->device->device->type;
+	const char *uuid = opt->device->uuid;
+	struct autoboot_option *auto_opt;
+	unsigned int i;
+
+	for (i = 0; i < config->n_autoboot_opts; i++) {
+		auto_opt = &config->autoboot_opts[i];
+		if (auto_opt->boot_type == BOOT_DEVICE_UUID)
+			if (!strcmp(auto_opt->uuid, uuid))
+				return DEFAULT_PRIORITY_LOCAL_FIRST + i;
+
+		if (auto_opt->boot_type == BOOT_DEVICE_TYPE)
+			if (auto_opt->type == type ||
+			    auto_opt->type == DEVICE_TYPE_ANY)
+				return DEFAULT_PRIORITY_LOCAL_FIRST + i;
+	}
+
+	return -1;
+}
+
+/*
+ * We have different priorities to resolve conflicts between boot options that
+ * report to be the default for their device. This function assigns a priority
+ * for these options.
+ */
+static enum default_priority default_option_priority(
+		struct discover_boot_option *opt)
+{
+	const struct config *config;
+
+	config = config_get();
+
+	/* We give highest priority to IPMI-configured boot options. If
+	 * we have an IPMI bootdev configuration set, then we don't allow
+	 * any other defaults */
+	if (config->ipmi_bootdev) {
+		bool ipmi_match = ipmi_device_type_matches(config->ipmi_bootdev,
+				opt->device->device->type);
+		if (ipmi_match)
+			return DEFAULT_PRIORITY_REMOTE;
+
+		pb_debug("handler: disabled default priority due to "
+				"non-matching IPMI type %x\n",
+				config->ipmi_bootdev);
+		return DEFAULT_PRIORITY_DISABLED;
+	}
+
+	/* Next, try to match the option against the user-defined autoboot
+	 * options, either by device UUID or type. */
+	if (config->n_autoboot_opts) {
+		int boot_match = autoboot_option_priority(config, opt);
+		if (boot_match > 0)
+			return boot_match;
+	}
+
+	/* If the option didn't match any entry in the array, it is disabled */
+	pb_debug("handler: disabled default priority due to "
+			"non-matching UUID or type\n");
+	return DEFAULT_PRIORITY_DISABLED;
+}
+
 static void set_default(struct device_handler *handler,
 		struct discover_boot_option *opt)
 {
-	if (handler->default_boot_option)
-		return;
+	enum default_priority cur_prio, new_prio;
 
 	if (!handler->autoboot_enabled)
 		return;
 
+	pb_debug("handler: new default option: %s\n", opt->option->id);
+
+	new_prio = default_option_priority(opt);
+
+	/* Anything outside our range prevents a default boot */
+	if (new_prio >= DEFAULT_PRIORITY_DISABLED)
+		return;
+
+	pb_debug("handler: calculated priority %d\n", new_prio);
+
+	/* Resolve any conflicts: if we have a new default option, it only
+	 * replaces the current if it has a higher priority. */
+	if (handler->default_boot_option) {
+
+		cur_prio = handler->default_boot_option_priority;
+
+		if (new_prio < cur_prio) {
+			pb_log("handler: new prio %d beats "
+					"old prio %d for %s\n",
+					new_prio, cur_prio,
+					handler->default_boot_option
+						->option->id);
+			handler->default_boot_option = opt;
+			handler->default_boot_option_priority = new_prio;
+			/* extend the timeout a little, so the user sees some
+			 * indication of the change */
+			handler->sec_to_boot += 2;
+		}
+
+		return;
+	}
+
+	handler->sec_to_boot = config_get()->autoboot_timeout_sec;
 	handler->default_boot_option = opt;
-	handler->sec_to_boot = DEFAULT_BOOT_TIMEOUT_SEC;
+	handler->default_boot_option_priority = new_prio;
 
-	pb_log("Boot option %s set as default, timeout %u sec.\n",
+	pb_log("handler: boot option %s set as default, timeout %u sec.\n",
 	       opt->option->id, handler->sec_to_boot);
 
 	default_timeout(handler);
@@ -452,7 +613,7 @@ static bool resource_resolve(struct resource *res, const char *name,
 	if (resource_is_resolved(res))
 		return true;
 
-	pb_log("Attempting to resolve resource %s->%s with parser %s\n",
+	pb_debug("Attempting to resolve resource %s->%s with parser %s\n",
 			opt->option->id, name, parser->name);
 	parser->resolve_resource(handler, res);
 
@@ -495,6 +656,18 @@ static void boot_option_finalise(struct device_handler *handler,
 		set_default(handler, opt);
 }
 
+static void notify_boot_option(struct device_handler *handler,
+		struct discover_boot_option *opt)
+{
+	struct discover_device *dev = opt->device;
+
+	if (!dev->notified)
+		discover_server_notify_device_add(handler->server,
+						  opt->device->device);
+	dev->notified = true;
+	discover_server_notify_boot_option_add(handler->server, opt->option);
+}
+
 static void process_boot_option_queue(struct device_handler *handler)
 {
 	struct discover_boot_option *opt, *tmp;
@@ -502,58 +675,48 @@ static void process_boot_option_queue(struct device_handler *handler)
 	list_for_each_entry_safe(&handler->unresolved_boot_options,
 			opt, tmp, list) {
 
-		pb_log("queue: attempting resolution for %s\n",
+		pb_debug("queue: attempting resolution for %s\n",
 				opt->option->id);
 
 		if (!boot_option_resolve(opt, handler))
 			continue;
 
-		pb_log("\tresolved!\n");
+		pb_debug("\tresolved!\n");
 
 		list_remove(&opt->list);
 		list_add_tail(&opt->device->boot_options, &opt->list);
 		talloc_steal(opt->device, opt);
 		boot_option_finalise(handler, opt);
-		discover_server_notify_boot_option_add(handler->server,
-							opt->option);
+		notify_boot_option(handler, opt);
 	}
 }
 
+struct discover_context *device_handler_discover_context_create(
+		struct device_handler *handler,
+		struct discover_device *device)
+{
+	struct discover_context *ctx;
+
+	ctx = talloc_zero(handler, struct discover_context);
+	ctx->device = device;
+	ctx->network = handler->network;
+	list_init(&ctx->boot_options);
+
+	return ctx;
+}
+
 /**
  * context_commit - Commit a temporary discovery context to the handler,
  * and notify the clients about any new options / devices
  */
-static void context_commit(struct device_handler *handler,
+void device_handler_discover_context_commit(struct device_handler *handler,
 		struct discover_context *ctx)
 {
 	struct discover_device *dev = ctx->device;
 	struct discover_boot_option *opt, *tmp;
-	unsigned int i, existing_device = 0;
-
-	/* do we already have this device? */
-	for (i = 0; i < handler->n_devices; i++) {
-		if (ctx->device == handler->devices[i]) {
-			existing_device = 1;
-			break;
-		}
-	}
-
-	/* if not already present, add the device to the handler's array */
-	if (!existing_device) {
-		handler->n_devices++;
-		handler->devices = talloc_realloc(handler, handler->devices,
-			struct discover_device *, handler->n_devices);
-		handler->devices[handler->n_devices - 1] = dev;
-		talloc_steal(handler, dev);
-
-		discover_server_notify_device_add(handler->server, dev->device);
-
-		/* this new device might be able to resolve existing boot
-		 * options */
-		pb_log("New device %s, processing queue\n", dev->device->id);
-		process_boot_option_queue(handler);
-	}
 
+	if (!device_lookup_by_id(handler, dev->device->id))
+		device_handler_add_device(handler, dev);
 
 	/* move boot options from the context to the device */
 	list_for_each_entry_safe(&ctx->boot_options, opt, tmp, list) {
@@ -566,8 +729,7 @@ static void context_commit(struct device_handler *handler,
 			list_add_tail(&dev->boot_options, &opt->list);
 			talloc_steal(dev, opt);
 			boot_option_finalise(handler, opt);
-			discover_server_notify_boot_option_add(handler->server,
-								opt->option);
+			notify_boot_option(handler, opt);
 		} else {
 			if (!opt->source->resolve_resource) {
 				pb_log("parser %s gave us an unresolved "
@@ -587,184 +749,231 @@ static void context_commit(struct device_handler *handler,
 	}
 }
 
-static int handle_add_udev_event(struct device_handler *handler,
-		struct event *event)
+void device_handler_add_device(struct device_handler *handler,
+		struct discover_device *device)
 {
-	struct discover_context *ctx;
-	struct discover_device *dev;
-	const char *param;
-	int rc;
+	handler->n_devices++;
+	handler->devices = talloc_realloc(handler, handler->devices,
+				struct discover_device *, handler->n_devices);
+	handler->devices[handler->n_devices - 1] = device;
 
-	/* create our context */
-	ctx = talloc(handler, struct discover_context);
-	ctx->event = event;
-	list_init(&ctx->boot_options);
+	if (device->device->type == DEVICE_TYPE_NETWORK)
+		network_register_device(handler->network, device);
+}
+
+void device_handler_add_ramdisk(struct device_handler *handler,
+		const char *path)
+{
+	struct ramdisk_device *dev;
+	unsigned int i;
 
-	/* create our top-level device */
-	dev = discover_device_create(handler, ctx, event);
+	if (!path)
+		return;
 
-	ctx->device = dev;
+	for (i = 0; i < handler->n_ramdisks; i++)
+		if (!strcmp(handler->ramdisks[i]->path, path))
+			return;
 
-	/* try to parse UUID and labels */
-	param = event_get_param(ctx->event, "ID_FS_UUID");
-	if (param)
-		dev->uuid = talloc_strdup(dev, param);
+	dev = talloc_zero(handler, struct ramdisk_device);
+	if (!dev) {
+		pb_log("Failed to allocate memory to track %s\n", path);
+		return;
+	}
 
-	param = event_get_param(ctx->event, "ID_FS_LABEL");
-	if (param)
-		dev->label = talloc_strdup(dev, param);
+	dev->path = talloc_strdup(handler, path);
 
-	rc = mount_device(dev);
-	if (rc) {
-		talloc_free(ctx);
-		return 0;
+	handler->ramdisks = talloc_realloc(handler, handler->ramdisks,
+				struct ramdisk_device *,
+				handler->n_ramdisks + 1);
+	if (!handler->ramdisks) {
+		pb_log("Failed to reallocate memory"
+		       "- ramdisk tracking inconsistent!\n");
+		return;
 	}
 
-	/* run the parsers. This will populate the ctx's boot_option list. */
-	iterate_parsers(ctx, CONF_METHOD_LOCAL_FILE);
+	handler->ramdisks[i] = dev;
+	i = handler->n_ramdisks++;
+}
 
-	/* add discovered stuff to the handler */
-	context_commit(handler, ctx);
+struct ramdisk_device *device_handler_get_ramdisk(
+		struct device_handler *handler)
+{
+	unsigned int i;
+	char *name;
+	dev_t id;
+
+	/* Check if free ramdisk exists */
+	for (i = 0; i < handler->n_ramdisks; i++)
+		if (!handler->ramdisks[i]->snapshot &&
+		    !handler->ramdisks[i]->origin &&
+		    !handler->ramdisks[i]->base)
+			return handler->ramdisks[i];
+
+	/* Otherwise create a new one */
+	name = talloc_asprintf(handler, "/dev/ram%d",
+			handler->n_ramdisks);
+	if (!name) {
+		pb_debug("Failed to allocate memory to name /dev/ram%d",
+			handler->n_ramdisks);
+		return NULL;
+	}
 
-	talloc_free(ctx);
+	id = makedev(1, handler->n_ramdisks);
+	if (mknod(name, S_IFBLK, id)) {
+		if (errno == EEXIST) {
+			/* We haven't yet received updates for existing
+			 * ramdisks - add and use this one */
+			pb_debug("Using untracked ramdisk %s\n", name);
+		} else {
+			pb_log("Failed to create new ramdisk %s: %s\n",
+			       name, strerror(errno));
+			return NULL;
+		}
+	}
+	device_handler_add_ramdisk(handler, name);
+	talloc_free(name);
 
-	return 0;
+	return handler->ramdisks[i];
 }
 
-static int handle_remove_udev_event(struct device_handler *handler,
-		struct event *event)
+void device_handler_release_ramdisk(struct discover_device *device)
 {
-	struct discover_device *dev;
+	struct ramdisk_device *ramdisk = device->ramdisk;
 
-	dev = find_device(handler, event->device);
-	if (!dev)
-		return 0;
+	talloc_free(ramdisk->snapshot);
+	talloc_free(ramdisk->origin);
+	talloc_free(ramdisk->base);
 
-	/* remove device from handler device array */
-	device_handler_remove(handler, dev);
+	ramdisk->snapshot = ramdisk->origin = ramdisk->base = NULL;
+	ramdisk->sectors = 0;
 
-	return 0;
+	device->ramdisk = NULL;
 }
 
-static int handle_add_user_event(struct device_handler *handler,
-		struct event *event)
+/* Start discovery on a hotplugged device. The device will be in our devices
+ * array, but has only just been initialised by the hotplug source.
+ */
+int device_handler_discover(struct device_handler *handler,
+		struct discover_device *dev)
 {
 	struct discover_context *ctx;
-	struct discover_device *dev;
+	struct boot_status *status;
 	int rc;
 
-	assert(event->device);
+	status = talloc_zero(handler, struct boot_status);
+	status->type = BOOT_STATUS_INFO;
+	/*
+	 * TRANSLATORS: this string will be passed the type and identifier
+	 * of the device. For example, the first parameter could be "Disk",
+	 * (which will be translated accordingly) and the second a Linux device
+	 * identifier like 'sda1' (which will not be translated)
+	 */
+	status->message = talloc_asprintf(status, _("Processing %s device %s"),
+				device_type_display_name(dev->device->type),
+				dev->device->id);
+	boot_status(handler, status);
+
+	process_boot_option_queue(handler);
 
-	ctx = talloc(handler, struct discover_context);
-	ctx->event = event;
-	list_init(&ctx->boot_options);
+	/* create our context */
+	ctx = device_handler_discover_context_create(handler, dev);
 
-	dev = discover_device_create(handler, ctx, event);
-	ctx->device = dev;
+	rc = mount_device(dev);
+	if (rc)
+		goto out;
 
-	rc = parse_user_event(ctx, event);
+	/* add this device to our system info */
+	system_info_register_blockdev(dev->device->id, dev->uuid,
+			dev->mount_path);
 
-	if (!rc)
-		context_commit(handler, ctx);
-
-	return rc;
-}
-
-static int handle_remove_user_event(struct device_handler *handler,
-		struct event *event)
-{
-	struct discover_device *dev = find_device(handler, event->device);
-
-	if (!dev)
-		return 0;
+	/* run the parsers. This will populate the ctx's boot_option list. */
+	iterate_parsers(ctx);
 
-	/* remove device from handler device array */
-	device_handler_remove(handler, dev);
+	/* add discovered stuff to the handler */
+	device_handler_discover_context_commit(handler, ctx);
+
+out:
+	/*
+	 * TRANSLATORS: the format specifier in this string is a Linux
+	 * device identifier, like 'sda1'
+	 */
+	status->message = talloc_asprintf(status,_("Processing %s complete"),
+				dev->device->id);
+	boot_status(handler, status);
+
+	talloc_free(status);
+	talloc_free(ctx);
 
 	return 0;
 }
 
-static enum conf_method parse_conf_method(const char *str)
-{
-
-	if (!strcasecmp(str, "dhcp")) {
-		return CONF_METHOD_DHCP;
-	}
-	return CONF_METHOD_UNKNOWN;
-}
-
-static int handle_conf_user_event(struct device_handler *handler,
-		struct event *event)
+/* Incoming dhcp event */
+int device_handler_dhcp(struct device_handler *handler,
+		struct discover_device *dev, struct event *event)
 {
 	struct discover_context *ctx;
-	struct discover_device *dev;
-	enum conf_method method;
-	const char *val;
+	struct boot_status *status;
+
+	status = talloc_zero(handler, struct boot_status);
+	status->type = BOOT_STATUS_INFO;
+	/*
+	 * TRANSLATORS: this format specifier will be the name of a network
+	 * device, like 'eth0'.
+	 */
+	status->message = talloc_asprintf(status, _("Processing dhcp event on %s"),
+				dev->device->id);
+	boot_status(handler, status);
 
-	ctx = talloc(handler, struct discover_context);
+	/* create our context */
+	ctx = device_handler_discover_context_create(handler, dev);
 	ctx->event = event;
-	list_init(&ctx->boot_options);
 
-	val = event_get_param(event, "url");
-	if (!val) {
-		talloc_free(ctx);
-		return 0;
-	}
+	iterate_parsers(ctx);
 
-	ctx->conf_url = pb_url_parse(ctx, val);
-	if (!ctx->conf_url) {
-		talloc_free(ctx);
-		return 0;
-	}
+	device_handler_discover_context_commit(handler, ctx);
 
-	val = event_get_param(event, "method");
-	if (!val) {
-		talloc_free(ctx);
-		return 0;
-	}
+	/*
+	 * TRANSLATORS: this format specifier will be the name of a network
+	 * device, like 'eth0'.
+	 */
+	status->message = talloc_asprintf(status,_("Processing %s complete"),
+				dev->device->id);
+	boot_status(handler, status);
 
-	method = parse_conf_method(val);
-	if (method == CONF_METHOD_UNKNOWN) {
-		talloc_free(ctx);
-		return 0;
-	}
+	talloc_free(status);
+	talloc_free(ctx);
 
-	dev = discover_device_create(handler, ctx, event);
-	ctx->device = dev;
+	return 0;
+}
 
-	iterate_parsers(ctx, method);
+/* incoming conf event */
+int device_handler_conf(struct device_handler *handler,
+		struct discover_device *dev, struct pb_url *url)
+{
+	struct discover_context *ctx;
+	struct boot_status *status;
 
-	context_commit(handler, ctx);
+	status = talloc_zero(handler, struct boot_status);
+	status->type = BOOT_STATUS_INFO;
+	status->message = talloc_asprintf(status, _("Processing user config"));
+	boot_status(handler, status);
 
-	return 0;
-}
+	/* create our context */
+	ctx = device_handler_discover_context_create(handler, dev);
+	ctx->conf_url = url;
 
-typedef int (*event_handler)(struct device_handler *, struct event *);
+	iterate_parsers(ctx);
 
-static event_handler handlers[EVENT_TYPE_MAX][EVENT_ACTION_MAX] = {
-	[EVENT_TYPE_UDEV] = {
-		[EVENT_ACTION_ADD]	= handle_add_udev_event,
-		[EVENT_ACTION_REMOVE]	= handle_remove_udev_event,
-	},
-	[EVENT_TYPE_USER] = {
-		[EVENT_ACTION_ADD]	= handle_add_user_event,
-		[EVENT_ACTION_REMOVE]	= handle_remove_user_event,
-		[EVENT_ACTION_CONF]	= handle_conf_user_event,
-	}
-};
+	device_handler_discover_context_commit(handler, ctx);
 
-int device_handler_event(struct device_handler *handler,
-		struct event *event)
-{
-	if (event->type >= EVENT_TYPE_MAX ||
-			event->action >= EVENT_ACTION_MAX ||
-			!handlers[event->type][event->action]) {
-		pb_log("%s unknown type/action: %d/%d\n", __func__,
-				event->type, event->action);
-		return 0;
-	}
+	status->message = talloc_asprintf(status,
+				_("Processing user config complete"));
+	boot_status(handler, status);
 
-	return handlers[event->type][event->action](handler, event);
+	talloc_free(status);
+	talloc_free(ctx);
+
+	return 0;
 }
 
 static struct discover_boot_option *find_boot_option_by_id(
@@ -787,11 +996,19 @@ static struct discover_boot_option *find_boot_option_by_id(
 void device_handler_boot(struct device_handler *handler,
 		struct boot_command *cmd)
 {
-	struct discover_boot_option *opt;
+	struct discover_boot_option *opt = NULL;
+
+	if (cmd->option_id && strlen(cmd->option_id))
+		opt = find_boot_option_by_id(handler, cmd->option_id);
 
-	opt = find_boot_option_by_id(handler, cmd->option_id);
+	if (handler->pending_boot)
+		boot_cancel(handler->pending_boot);
 
-	boot(handler, opt, cmd, handler->dry_run, boot_status, handler);
+	platform_pre_boot();
+
+	handler->pending_boot = boot(handler, opt, cmd, handler->dry_run,
+			boot_status, handler);
+	handler->pending_boot_is_default = false;
 }
 
 void device_handler_cancel_default(struct device_handler *handler)
@@ -810,13 +1027,534 @@ void device_handler_cancel_default(struct device_handler *handler)
 
 	pb_log("Cancelling default boot option\n");
 
+	if (handler->pending_boot && handler->pending_boot_is_default) {
+		boot_cancel(handler->pending_boot);
+		handler->pending_boot = NULL;
+		handler->pending_boot_is_default = false;
+	}
+
 	handler->default_boot_option = NULL;
 
 	status.type = BOOT_STATUS_INFO;
 	status.progress = -1;
 	status.detail = NULL;
-	status.message = "Default boot cancelled";
+	status.message = _("Default boot cancelled");
 
 	discover_server_notify_boot_status(handler->server, &status);
 }
+
+void device_handler_update_config(struct device_handler *handler,
+		struct config *config)
+{
+	int rc;
+
+	rc = config_set(config);
+	if (rc)
+		return;
+
+	discover_server_notify_config(handler->server, config);
+	device_handler_update_lang(config->lang);
+	device_handler_reinit(handler);
+}
+
+static char *device_from_addr(void *ctx, struct pb_url *url)
+{
+	char *ipaddr, *buf, *tok, *dev = NULL;
+	const char *delim = " ";
+	struct sockaddr_in *ip;
+	struct sockaddr_in si;
+	struct addrinfo *res;
+	struct process *p;
+	int rc;
+
+	/* Note: IPv4 only */
+	rc = inet_pton(AF_INET, url->host, &(si.sin_addr));
+	if (rc > 0) {
+		ipaddr = url->host;
+	} else {
+		/* need to turn hostname into a valid IP */
+		rc = getaddrinfo(url->host, NULL, NULL, &res);
+		if (rc) {
+			pb_debug("%s: Invalid URL\n",__func__);
+			return NULL;
+		}
+		ipaddr = talloc_array(ctx,char,INET_ADDRSTRLEN);
+		ip = (struct sockaddr_in *) res->ai_addr;
+		inet_ntop(AF_INET, &(ip->sin_addr), ipaddr, INET_ADDRSTRLEN);
+		freeaddrinfo(res);
+	}
+
+	const char *argv[] = {
+		pb_system_apps.ip,
+		"route", "show", "to", "match",
+		ipaddr,
+		NULL
+	};
+
+	p = process_create(ctx);
+
+	p->path = pb_system_apps.ip;
+	p->argv = argv;
+	p->keep_stdout = true;
+
+	rc = process_run_sync(p);
+
+	if (rc) {
+		/* ip has complained for some reason; most likely
+		 * there is no route to the host - bail out */
+		pb_debug("%s: No route to %s\n",__func__,url->host);
+		return NULL;
+	}
+
+	buf = p->stdout_buf;
+	/* If a route is found, ip-route output will be of the form
+	 * "... dev DEVNAME ... " */
+	tok = strtok(buf, delim);
+	while (tok) {
+		if (!strcmp(tok, "dev")) {
+			tok = strtok(NULL, delim);
+			dev = talloc_strdup(ctx, tok);
+			break;
+		}
+		tok = strtok(NULL, delim);
+	}
+
+	process_release(p);
+	if (dev)
+		pb_debug("%s: Found interface '%s'\n", __func__,dev);
+	return dev;
+}
+
+void device_handler_process_url(struct device_handler *handler,
+		const char *url, const char *mac, const char *ip)
+{
+	struct discover_context *ctx;
+	struct discover_device *dev;
+	struct boot_status *status;
+	struct pb_url *pb_url;
+	struct event *event;
+	struct param *param;
+
+	status = talloc(handler, struct boot_status);
+
+	status->type = BOOT_STATUS_ERROR;
+	status->progress = 0;
+	status->detail = talloc_asprintf(status,
+			_("Received config URL %s"), url);
+
+	if (!handler->network) {
+		status->message = talloc_asprintf(handler,
+					_("No network configured"));
+		goto msg;
+	}
+
+	event = talloc(handler, struct event);
+	event->type = EVENT_TYPE_USER;
+	event->action = EVENT_ACTION_CONF;
+
+	if (url[strlen(url) - 1] == '/') {
+		event->params = talloc_array(event, struct param, 3);
+		param = &event->params[0];
+		param->name = talloc_strdup(event, "pxepathprefix");
+		param->value = talloc_strdup(event, url);
+		param = &event->params[1];
+		param->name = talloc_strdup(event, "mac");
+		param->value = talloc_strdup(event, mac);
+		param = &event->params[2];
+		param->name = talloc_strdup(event, "ip");
+		param->value = talloc_strdup(event, ip);
+		event->n_params = 3;
+	} else {
+		event->params = talloc_array(event, struct param, 1);
+		param = &event->params[0];
+		param->name = talloc_strdup(event, "pxeconffile");
+		param->value = talloc_strdup(event, url);
+		event->n_params = 1;
+	}
+
+	pb_url = pb_url_parse(event, event->params->value);
+	if (!pb_url || !pb_url->host) {
+		status->message = talloc_asprintf(handler,
+					_("Invalid config URL!"));
+		goto msg;
+	}
+
+	event->device = device_from_addr(event, pb_url);
+	if (!event->device) {
+		status->message = talloc_asprintf(status,
+					_("Unable to route to host %s"),
+					pb_url->host);
+		goto msg;
+	}
+
+	dev = discover_device_create(handler, event->device);
+	ctx = device_handler_discover_context_create(handler, dev);
+	ctx->event = event;
+
+	iterate_parsers(ctx);
+
+	device_handler_discover_context_commit(handler, ctx);
+
+	talloc_free(ctx);
+
+	status->type = BOOT_STATUS_INFO;
+	status->message = talloc_asprintf(status, _("Config file %s parsed"),
+					pb_url->file);
+msg:
+	boot_status(handler, status);
+	talloc_free(status);
+}
+
+#ifndef PETITBOOT_TEST
+
+static void device_handler_update_lang(const char *lang)
+{
+	const char *cur_lang;
+
+	if (!lang)
+		return;
+
+	cur_lang = setlocale(LC_ALL, NULL);
+	if (cur_lang && !strcmp(cur_lang, lang))
+		return;
+
+	setlocale(LC_ALL, lang);
+}
+
+static int device_handler_init_sources(struct device_handler *handler)
+{
+	/* init our device sources: udev, network and user events */
+	handler->udev = udev_init(handler, handler->waitset);
+	if (!handler->udev)
+		return -1;
+
+	handler->network = network_init(handler, handler->waitset,
+			handler->dry_run);
+	if (!handler->network)
+		return -1;
+
+	handler->user_event = user_event_init(handler, handler->waitset);
+	if (!handler->user_event)
+		return -1;
+
+	return 0;
+}
+
+static void device_handler_reinit_sources(struct device_handler *handler)
+{
+	/* if we haven't initialised sources previously (becuase we started in
+	 * safe mode), then init once here. */
+	if (!(handler->udev || handler->network || handler->user_event)) {
+		device_handler_init_sources(handler);
+		return;
+	}
+
+	udev_reinit(handler->udev);
+
+	network_shutdown(handler->network);
+	handler->network = network_init(handler, handler->waitset,
+			handler->dry_run);
+}
+
+static const char *fs_parameters(struct discover_device *dev,
+				 unsigned int rw_flags)
+{
+	const char *fstype = discover_device_get_param(dev, "ID_FS_TYPE");
+
+	/* XFS journals are not cross-endian compatible; don't try recovery
+	 * even if we have a snapshot */
+	if (!strncmp(fstype, "xfs", strlen("xfs")))
+		return "norecovery";
+
+	/* If we have a snapshot available allow touching the filesystem */
+	if (dev->ramdisk)
+		return "";
+
+	if ((rw_flags | MS_RDONLY) != MS_RDONLY)
+		return "";
+
+	/* Avoid writes due to journal replay if we don't have a snapshot */
+	if (!strncmp(fstype, "ext4", strlen("ext4")))
+		return "norecovery";
+
+	return "";
+}
+
+static inline const char *get_device_path(struct discover_device *dev)
+{
+	return dev->ramdisk ? dev->ramdisk->snapshot : dev->device_path;
+}
+
+static bool check_existing_mount(struct discover_device *dev)
+{
+	struct stat devstat, mntstat;
+	const char *device_path;
+	struct mntent *mnt;
+	FILE *fp;
+	int rc;
+
+	device_path = get_device_path(dev);
+
+	rc = stat(device_path, &devstat);
+	if (rc) {
+		pb_debug("%s: stat failed: %s\n", __func__, strerror(errno));
+		return false;
+	}
+
+	if (!S_ISBLK(devstat.st_mode)) {
+		pb_debug("%s: %s isn't a block device?\n", __func__,
+				dev->device_path);
+		return false;
+	}
+
+	fp = fopen("/proc/self/mounts", "r");
+
+	for (;;) {
+		mnt = getmntent(fp);
+		if (!mnt)
+			break;
+
+		if (!mnt->mnt_fsname || mnt->mnt_fsname[0] != '/')
+			continue;
+
+		rc = stat(mnt->mnt_fsname, &mntstat);
+		if (rc)
+			continue;
+
+		if (!S_ISBLK(mntstat.st_mode))
+			continue;
+
+		if (mntstat.st_rdev == devstat.st_rdev) {
+			dev->mount_path = talloc_strdup(dev, mnt->mnt_dir);
+			dev->mounted_rw = !!hasmntopt(mnt, "rw");
+			dev->mounted = true;
+			dev->unmount = false;
+
+			pb_debug("%s: %s is already mounted (r%c) at %s\n",
+					__func__, dev->device_path,
+					dev->mounted_rw ? 'w' : 'o',
+					mnt->mnt_dir);
+			break;
+		}
+	}
+
+	fclose(fp);
+
+	return mnt != NULL;
+}
+
+static int mount_device(struct discover_device *dev)
+{
+	const char *fstype, *device_path;
+	int rc;
+
+	if (!dev->device_path)
+		return -1;
+
+	if (dev->mounted)
+		return 0;
+
+	if (check_existing_mount(dev))
+		return 0;
+
+	fstype = discover_device_get_param(dev, "ID_FS_TYPE");
+	if (!fstype)
+		return 0;
+
+	/* ext3 treats the norecovery option as an error, so mount the device
+	 * as an ext4 filesystem instead */
+	if (!strncmp(fstype, "ext3", strlen("ext3"))) {
+		pb_debug("Mounting ext3 filesystem as ext4\n");
+		fstype = talloc_asprintf(dev, "ext4");
+	}
+
+	dev->mount_path = join_paths(dev, mount_base(),
+					dev->device_path);
+
+	if (pb_mkdir_recursive(dev->mount_path)) {
+		pb_log("couldn't create mount directory %s: %s\n",
+				dev->mount_path, strerror(errno));
+		goto err_free;
+	}
+
+	device_path = get_device_path(dev);
+
+	pb_log("mounting device %s read-only\n", dev->device_path);
+	errno = 0;
+	rc = mount(device_path, dev->mount_path, fstype,
+			MS_RDONLY | MS_SILENT,
+			fs_parameters(dev, MS_RDONLY));
+	if (!rc) {
+		dev->mounted = true;
+		dev->mounted_rw = false;
+		dev->unmount = true;
+		return 0;
+	}
+
+	pb_log("couldn't mount device %s: mount failed: %s\n",
+			device_path, strerror(errno));
+
+	/* If mount fails clean up any snapshot */
+	devmapper_destroy_snapshot(dev);
+
+	pb_rmdir_recursive(mount_base(), dev->mount_path);
+err_free:
+	talloc_free(dev->mount_path);
+	dev->mount_path = NULL;
+	return -1;
+}
+
+static int umount_device(struct discover_device *dev)
+{
+	const char *device_path;
+	int rc;
+
+	if (!dev->mounted || !dev->unmount)
+		return 0;
+
+	device_path = get_device_path(dev);
+
+	pb_log("unmounting device %s\n", device_path);
+	rc = umount(dev->mount_path);
+	if (rc)
+		return -1;
+
+	dev->mounted = false;
+	devmapper_destroy_snapshot(dev);
+
+	pb_rmdir_recursive(mount_base(), dev->mount_path);
+
+	talloc_free(dev->mount_path);
+	dev->mount_path = NULL;
+
+	return 0;
+}
+
+int device_request_write(struct discover_device *dev, bool *release)
+{
+	const char *fstype, *device_path;
+	const struct config *config;
+	int rc;
+
+	*release = false;
+
+	config = config_get();
+	if (!config->allow_writes)
+		return -1;
+
+	if (!dev->mounted)
+		return -1;
+
+	if (dev->mounted_rw)
+		return 0;
+
+	fstype = discover_device_get_param(dev, "ID_FS_TYPE");
+
+	device_path = get_device_path(dev);
+
+	pb_log("remounting device %s read-write\n", device_path);
+
+	rc = umount(dev->mount_path);
+	if (rc) {
+		pb_log("Failed to unmount %s: %s\n",
+		       dev->mount_path, strerror(errno));
+		return -1;
+	}
+
+	rc = mount(device_path, dev->mount_path, fstype,
+			MS_SILENT,
+			fs_parameters(dev, MS_REMOUNT));
+	if (rc)
+		goto mount_ro;
+
+	dev->mounted_rw = true;
+	*release = true;
+	return 0;
+
+mount_ro:
+	pb_log("Unable to remount device %s read-write: %s\n",
+	       device_path, strerror(errno));
+	if (mount(device_path, dev->mount_path, fstype,
+			MS_RDONLY | MS_SILENT,
+			fs_parameters(dev, MS_RDONLY)))
+		pb_log("Unable to recover mount for %s: %s\n",
+		       device_path, strerror(errno));
+	return -1;
+}
+
+void device_release_write(struct discover_device *dev, bool release)
+{
+	const char *fstype, *device_path;
+
+	if (!release)
+		return;
+
+	device_path = get_device_path(dev);
+
+	fstype = discover_device_get_param(dev, "ID_FS_TYPE");
+
+	pb_log("remounting device %s read-only\n", device_path);
+
+	if (umount(dev->mount_path)) {
+		pb_log("Failed to unmount %s\n", dev->mount_path);
+		return;
+	}
+	dev->mounted_rw = dev->mounted = false;
+
+	if (dev->ramdisk) {
+		devmapper_merge_snapshot(dev);
+		/* device_path becomes stale after merge */
+		device_path = get_device_path(dev);
+	}
+
+	if (mount(device_path, dev->mount_path, fstype,
+			MS_RDONLY | MS_SILENT,
+			fs_parameters(dev, MS_RDONLY)))
+		pb_log("Failed to remount %s read-only: %s\n",
+		       device_path, strerror(errno));
+	else
+		dev->mounted = true;
+}
+
+#else
+
+static void device_handler_update_lang(const char *lang __attribute__((unused)))
+{
+}
+
+static int device_handler_init_sources(
+		struct device_handler *handler __attribute__((unused)))
+{
+	return 0;
+}
+
+static void device_handler_reinit_sources(
+		struct device_handler *handler __attribute__((unused)))
+{
+}
+
+static int umount_device(struct discover_device *dev __attribute__((unused)))
+{
+	return 0;
+}
+
+static int __attribute__((unused)) mount_device(
+		struct discover_device *dev __attribute__((unused)))
+{
+	return 0;
+}
+
+int device_request_write(struct discover_device *dev __attribute__((unused)),
+		bool *release)
+{
+	*release = true;
+	return 0;
+}
+
+void device_release_write(struct discover_device *dev __attribute__((unused)),
+	bool release __attribute__((unused)))
+{
+}
+
 #endif
+