X-Git-Url: http://git.ozlabs.org/?p=petitboot;a=blobdiff_plain;f=discover%2Fdevice-handler.c;h=120f11f52aa819639ece6a1bffaa49d0772921ae;hp=95d203920d6f72bf5176c2629e7d2f4aa430a447;hb=01dac4f074301097d10abb6130eb68f99f56a1b9;hpb=7a0a735a5c1db0e0b1816300c8ad211326bfcde6

diff --git a/discover/device-handler.c b/discover/device-handler.c
index 95d2039..120f11f 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>
@@ -15,19 +17,34 @@
 #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 "user-event.h"
+#include "platform.h"
 #include "event.h"
 #include "parser.h"
 #include "resource.h"
 #include "paths.h"
+#include "sysinfo.h"
 #include "boot.h"
+#include "udev.h"
+#include "network.h"
 
 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;
 
@@ -38,11 +55,19 @@ struct device_handler {
 
 	struct discover_boot_option *default_boot_option;
 	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)
 {
@@ -103,6 +128,12 @@ 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 *),
@@ -154,6 +185,13 @@ 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);
@@ -232,7 +270,7 @@ const char *discover_device_get_param(struct discover_device *device,
 
 	list_for_each_entry(&device->params, param, list) {
 		if (!strcmp(param->name, name))
-			return param->name;
+			return param->value;
 	}
 	return NULL;
 }
@@ -241,6 +279,7 @@ struct device_handler *device_handler_init(struct discover_server *server,
 		struct waitset *waitset, int dry_run)
 {
 	struct device_handler *handler;
+	int rc;
 
 	handler = talloc_zero(NULL, struct device_handler);
 	handler->server = server;
@@ -255,12 +294,47 @@ struct device_handler *device_handler_init(struct discover_server *server,
 
 	parser_init();
 
+	if (config_get()->safe_mode)
+		return handler;
+
+	rc = device_handler_init_sources(handler);
+	if (rc) {
+		talloc_free(handler);
+		return NULL;
+	}
+
 	return handler;
 }
 
+void device_handler_reinit(struct device_handler *handler)
+{
+	struct discover_boot_option *opt, *tmp;
+	unsigned int i;
+
+	device_handler_cancel_default(handler);
+
+	/* 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);
+
+	/* drop all devices */
+	for (i = 0; i < handler->n_devices; i++)
+		discover_server_notify_device_remove(handler->server,
+				handler->devices[i]->device);
+
+	talloc_free(handler->devices);
+	handler->devices = NULL;
+	handler->n_devices = 0;
+
+	device_handler_reinit_sources(handler);
+}
+
 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++)
@@ -272,6 +346,21 @@ void device_handler_remove(struct device_handler *handler,
 		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]));
@@ -301,7 +390,7 @@ 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);
 
@@ -316,6 +405,9 @@ 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) {
@@ -331,50 +423,80 @@ static int default_timeout(void *arg)
 
 	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;
 }
 
 static bool priority_match(struct boot_priority *prio,
 		struct discover_boot_option *opt)
 {
-	return prio->type == opt->device->device->type;
+	return prio->type == opt->device->device->type ||
+		prio->type == DEVICE_TYPE_ANY;
 }
 
 static int default_option_priority(struct discover_boot_option *opt)
 {
 	const struct config *config;
 	struct boot_priority *prio;
-	int i;
+	unsigned int i;
 
 	config = config_get();
 
 	for (i = 0; i < config->n_boot_priorities; i++) {
 		prio = &config->boot_priorities[i];
 		if (priority_match(prio, opt))
-			break;
+			return prio->priority;
 	}
 
-	return i;
+	return 0;
+}
+
+static bool device_allows_default(struct discover_device *dev)
+{
+	const char *dev_str;
+
+	dev_str = config_get()->boot_device;
+
+	if (!dev_str || !strlen(dev_str))
+		return true;
+
+	/* default devices are specified by UUIDs at present */
+	if (strcmp(dev->uuid, dev_str))
+		return false;
+
+	return true;
 }
 
 static void set_default(struct device_handler *handler,
 		struct discover_boot_option *opt)
 {
+	int new_prio;
+
 	if (!handler->autoboot_enabled)
 		return;
 
+	/* do we allow default-booting from this device? */
+	if (!device_allows_default(opt->device))
+		return;
+
+	new_prio = default_option_priority(opt);
+
+	/* A negative priority indicates that we don't want to boot this device
+	 * by default */
+	if (new_prio < 0)
+		return;
+
 	/* 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) {
-		int new_prio, cur_prio;
+		int cur_prio;
 
-		new_prio = default_option_priority(opt);
 		cur_prio = default_option_priority(
 					handler->default_boot_option);
 
-		if (new_prio < cur_prio) {
+		if (new_prio > cur_prio) {
 			handler->default_boot_option = opt;
 			/* extend the timeout a little, so the user sees some
 			 * indication of the change */
@@ -418,7 +540,7 @@ 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);
 
@@ -480,13 +602,13 @@ 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);
@@ -502,9 +624,8 @@ struct discover_context *device_handler_discover_context_create(
 {
 	struct discover_context *ctx;
 
-	ctx = talloc(handler, struct discover_context);
+	ctx = talloc_zero(handler, struct discover_context);
 	ctx->device = device;
-	ctx->conf_url = NULL;
 	list_init(&ctx->boot_options);
 
 	return ctx;
@@ -562,46 +683,55 @@ void device_handler_add_device(struct device_handler *handler,
 				struct discover_device *, handler->n_devices);
 	handler->devices[handler->n_devices - 1] = device;
 
+	if (device->device->type == DEVICE_TYPE_NETWORK)
+		network_register_device(handler->network, device);
 }
 
 /* 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, enum conf_method method)
+		struct discover_device *dev)
 {
 	struct discover_context *ctx;
+	int rc;
 
 	process_boot_option_queue(handler);
 
 	/* create our context */
 	ctx = device_handler_discover_context_create(handler, dev);
 
-	mount_device(dev);
+	rc = mount_device(dev);
+	if (rc)
+		goto out;
+
+	/* add this device to our system info */
+	system_info_register_blockdev(dev->device->id, dev->uuid,
+			dev->mount_path);
 
 	/* run the parsers. This will populate the ctx's boot_option list. */
-	iterate_parsers(ctx, method);
+	iterate_parsers(ctx);
 
 	/* add discovered stuff to the handler */
 	device_handler_discover_context_commit(handler, ctx);
 
+out:
 	talloc_free(ctx);
 
 	return 0;
 }
 
-/* incoming conf event */
-int device_handler_conf(struct device_handler *handler,
-		struct discover_device *dev, struct pb_url *url,
-		enum conf_method method)
+/* Incoming dhcp event */
+int device_handler_dhcp(struct device_handler *handler,
+		struct discover_device *dev, struct event *event)
 {
 	struct discover_context *ctx;
 
 	/* create our context */
 	ctx = device_handler_discover_context_create(handler, dev);
-	ctx->conf_url = url;
+	ctx->event = event;
 
-	iterate_parsers(ctx, method);
+	iterate_parsers(ctx);
 
 	device_handler_discover_context_commit(handler, ctx);
 
@@ -610,6 +740,25 @@ int device_handler_conf(struct device_handler *handler,
 	return 0;
 }
 
+/* incoming conf event */
+int device_handler_conf(struct device_handler *handler,
+		struct discover_device *dev, struct pb_url *url)
+{
+        struct discover_context *ctx;
+
+        /* create our context */
+        ctx = device_handler_discover_context_create(handler, dev);
+        ctx->conf_url = url;
+
+        iterate_parsers(ctx);
+
+        device_handler_discover_context_commit(handler, ctx);
+
+        talloc_free(ctx);
+
+        return 0;
+}
+
 static struct discover_boot_option *find_boot_option_by_id(
 		struct device_handler *handler, const char *id)
 {
@@ -630,11 +779,16 @@ 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;
 
-	opt = find_boot_option_by_id(handler, cmd->option_id);
+	if (cmd->option_id && strlen(cmd->option_id))
+		opt = find_boot_option_by_id(handler, cmd->option_id);
 
-	boot(handler, opt, cmd, handler->dry_run, boot_status, handler);
+	if (handler->pending_boot)
+		boot_cancel(handler->pending_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)
@@ -653,69 +807,398 @@ 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)
+{
+	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;
+
+	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 bool check_existing_mount(struct discover_device *dev)
+{
+	struct stat devstat, mntstat;
+	struct mntent *mnt;
+	FILE *fp;
+	int rc;
+
+	rc = stat(dev->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;
 	int rc;
 
 	if (!dev->device_path)
 		return -1;
 
-	if (!dev->mount_path)
-		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));
+	if (dev->mounted)
+		return 0;
 
-	rc = process_run_simple(dev, pb_system_apps.mount,
-			dev->device_path, dev->mount_path,
-			"-o", "ro", NULL);
+	if (check_existing_mount(dev))
+		return 0;
 
-	if (!rc)
+	fstype = discover_device_get_param(dev, "ID_FS_TYPE");
+	if (!fstype)
 		return 0;
 
-	/* Retry mount without ro option. */
-	rc = process_run_simple(dev, pb_system_apps.mount,
-			dev->device_path, dev->mount_path, NULL);
+	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;
+	}
 
-	if (!rc)
+	pb_log("mounting device %s read-only\n", dev->device_path);
+	errno = 0;
+	rc = mount(dev->device_path, dev->mount_path, fstype,
+			MS_RDONLY | MS_SILENT, "");
+	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",
+			dev->device_path, strerror(errno));
 
 	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)
 {
-	int status;
+	int rc;
 
-	if (!dev->mount_path)
+	if (!dev->mounted || !dev->unmount)
 		return 0;
 
-	status = process_run_simple(dev, pb_system_apps.umount,
-			dev->mount_path, NULL);
-
-	if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
+	pb_log("unmounting device %s\n", dev->device_path);
+	rc = umount(dev->mount_path);
+	if (rc)
 		return -1;
 
+	dev->mounted = false;
+
 	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)
+{
+	int rc;
+
+	*release = false;
+
+	if (!dev->mounted)
+		return -1;
+
+	if (dev->mounted_rw)
+		return 0;
+
+	pb_log("remounting device %s read-write\n", dev->device_path);
+	rc = mount(dev->device_path, dev->mount_path, "",
+			MS_REMOUNT | MS_SILENT, "");
+	if (rc)
+		return -1;
+
+	dev->mounted_rw = true;
+	*release = true;
 	return 0;
 }
+
+void device_release_write(struct discover_device *dev, bool release)
+{
+	if (!release)
+		return;
+
+	pb_log("remounting device %s read-only\n", dev->device_path);
+	mount(dev->device_path, dev->mount_path, "",
+			MS_REMOUNT | MS_RDONLY | MS_SILENT, "");
+	dev->mounted_rw = false;
+}
+
 #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;
@@ -727,5 +1210,17 @@ static int __attribute__((unused)) mount_device(
 	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