discover: extend URL in UI to support auto-discovery
[petitboot] / discover / device-handler.c
index 5d40ebe99642711e6f17d9f4b2d113e94f7bfc4c..5df070073b4d298c8a49a5488010434b73ff4f32 100644 (file)
-
+#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 <talloc/talloc.h>
-#include <pb-protocol/pb-protocol.h>
+#include <list/list.h>
+#include <log/log.h>
+#include <types/types.h>
+#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 "udev.h"
-#include "log.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 "paths.h"
+#include "sysinfo.h"
+#include "boot.h"
+#include "udev.h"
+#include "network.h"
+#include "ipmi.h"
 
-#define MOUNT_BIN "/bin/mount"
+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;
+       struct discover_server  *server;
+       int                     dry_run;
 
-       struct device *devices;
-       int n_devices;
-};
+       struct pb_udev          *udev;
+       struct network          *network;
+       struct user_event       *user_event;
 
-struct discover_context {
-       char *device_path;
-       char *mount_path;
-       struct udev_event *event;
-       struct device *device;
-       char **links;
-       int n_links;
-};
+       struct discover_device  **devices;
+       unsigned int            n_devices;
 
-struct mount_map {
-       char *device_path;
-       char *mount_point;
-};
+       struct ramdisk_device   **ramdisks;
+       unsigned int            n_ramdisks;
 
+       struct waitset          *waitset;
+       struct waiter           *timeout_waiter;
+       bool                    autoboot_enabled;
+       unsigned int            sec_to_boot;
 
-static struct boot_option options[] = {
-       {
-               .id = "1.1",
-               .name = "meep one",
-               .description = "meep description one",
-               .icon_file = "meep.one.png",
-               .boot_args = "root=/dev/sda1",
-       },
-};
+       struct discover_boot_option *default_boot_option;
+       int                     default_boot_option_priority;
+
+       struct list             unresolved_boot_options;
 
-static struct device device = {
-       .id = "1",
-       .name = "meep",
-       .description = "meep description",
-       .icon_file = "meep.png",
-       .n_options = 1,
-       .options = options,
+       struct boot_task        *pending_boot;
+       bool                    pending_boot_is_default;
 };
 
-int device_handler_get_current_devices(struct device_handler *handler,
-               struct device **devices)
+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)
 {
-       *devices = &device;
-       return 1;
+       boot_option->source = ctx->parser;
+       list_add_tail(&ctx->boot_options, &boot_option->list);
+       talloc_steal(ctx, boot_option);
 }
 
-static int mkdir_recursive(const char *dir)
+/**
+ * device_handler_get_device_count - Get the count of current handler devices.
+ */
+
+int device_handler_get_device_count(const struct device_handler *handler)
 {
-       struct stat statbuf;
-       char *str, *sep;
-       int mode = 0755;
+       return handler->n_devices;
+}
 
-       if (!*dir)
-               return 0;
+/**
+ * device_handler_get_device - Get a handler device by index.
+ */
 
-       if (!stat(dir, &statbuf)) {
-               if (!S_ISDIR(statbuf.st_mode)) {
-                       pb_log("%s: %s exists, but isn't a directory\n",
-                                       __func__, dir);
-                       return -1;
-               }
-               return 0;
+const struct discover_device *device_handler_get_device(
+       const struct device_handler *handler, unsigned int index)
+{
+       if (index >= handler->n_devices) {
+               assert(0 && "bad index");
+               return NULL;
+       }
+
+       return handler->devices[index];
+}
+
+struct discover_boot_option *discover_boot_option_create(
+               struct discover_context *ctx,
+               struct discover_device *device)
+{
+       struct discover_boot_option *opt;
+
+       opt = talloc_zero(ctx, struct discover_boot_option);
+       opt->option = talloc_zero(opt, struct boot_option);
+       opt->device = device;
+
+       return opt;
+}
+
+static int device_match_uuid(struct discover_device *dev, const char *uuid)
+{
+       return dev->uuid && !strcmp(dev->uuid, uuid);
+}
+
+static int device_match_label(struct discover_device *dev, const char *label)
+{
+       return dev->label && !strcmp(dev->label, label);
+}
+
+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 *),
+               const char *str)
+{
+       struct discover_device *dev;
+       unsigned int i;
+
+       if (!str)
+               return NULL;
+
+       for (i = 0; i < device_handler->n_devices; i++) {
+               dev = device_handler->devices[i];
+
+               if (match_fn(dev, str))
+                       return dev;
        }
 
-       str = talloc_strdup(NULL, dir);
-       sep = strchr(*str == '/' ? str + 1 : str, '/');
+       return NULL;
+}
+
+struct discover_device *device_lookup_by_name(struct device_handler *handler,
+               const char *name)
+{
+       if (!strncmp(name, "/dev/", strlen("/dev/")))
+               name += strlen("/dev/");
+
+       return device_lookup_by_id(handler, name);
+}
+
+struct discover_device *device_lookup_by_uuid(
+               struct device_handler *device_handler,
+               const char *uuid)
+{
+       return device_lookup(device_handler, device_match_uuid, uuid);
+}
+
+struct discover_device *device_lookup_by_label(
+               struct device_handler *device_handler,
+               const char *label)
+{
+       return device_lookup(device_handler, device_match_label, label);
+}
+
+struct discover_device *device_lookup_by_id(
+               struct device_handler *device_handler,
+               const char *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);
+}
 
-       while (1) {
+static int destroy_device(void *arg)
+{
+       struct discover_device *dev = arg;
 
-               /* terminate the path at sep */
-               if (sep)
-                       *sep = '\0';
+       umount_device(dev);
 
-               if (mkdir(str, mode) && errno != EEXIST) {
-                       pb_log("mkdir(%s): %s\n", str, strerror(errno));
-                       return -1;
+       return 0;
+}
+
+struct discover_device *discover_device_create(struct device_handler *handler,
+               const char *id)
+{
+       struct discover_device *dev;
+
+       dev = device_lookup_by_id(handler, id);
+       if (dev)
+               return dev;
+
+       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);
+
+       talloc_set_destructor(dev, destroy_device);
+
+       return dev;
+}
+
+struct discover_device_param {
+       char                    *name;
+       char                    *value;
+       struct list_item        list;
+};
+
+void discover_device_set_param(struct discover_device *device,
+               const char *name, const char *value)
+{
+       struct discover_device_param *param;
+       bool found = false;
+
+       list_for_each_entry(&device->params, param, list) {
+               if (!strcmp(param->name, name)) {
+                       found = true;
+                       break;
+               }
+       }
+
+       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);
+       }
+
+       param->value = talloc_strdup(param, value);
+}
+
+const char *discover_device_get_param(struct discover_device *device,
+               const char *name)
+{
+       struct discover_device_param *param;
+
+       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;
 
-               if (!sep)
+       handler = talloc_zero(NULL, struct device_handler);
+       handler->server = server;
+       handler->waitset = waitset;
+       handler->dry_run = dry_run;
+       handler->autoboot_enabled = config_get()->autoboot_enabled;
+
+       list_init(&handler->unresolved_boot_options);
+
+       /* set up our mount point base */
+       pb_mkdir_recursive(mount_base());
+
+       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;
+       struct ramdisk_device *ramdisk;
+       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);
+               ramdisk = handler->devices[i]->ramdisk;
+               talloc_free(handler->devices[i]);
+               talloc_free(ramdisk);
+       }
+
+       talloc_free(handler->devices);
+       handler->devices = NULL;
+       handler->n_devices = 0;
+       talloc_free(handler->ramdisks);
+       handler->ramdisks = NULL;
+       handler->n_ramdisks = 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++)
+               if (handler->devices[i] == device)
                        break;
 
-               /* reset dir to the full path */
-               strcpy(str, dir);
-               sep = strchr(sep + 1, '/');
+       if (i == handler->n_devices) {
+               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);
        }
 
-       talloc_free(str);
+       /* 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);
+
+       if (device->notified)
+               discover_server_notify_device_remove(handler->server,
+                                                       device->device);
+
+       talloc_free(device);
+}
+
+static void boot_status(void *arg, struct boot_status *status)
+{
+       struct device_handler *handler = arg;
+
+       discover_server_notify_boot_status(handler->server, status);
+}
+
+static void countdown_status(struct device_handler *handler,
+               struct discover_boot_option *opt, unsigned int sec)
+{
+       struct boot_status status;
+
+       status.type = BOOT_STATUS_INFO;
+       status.progress = -1;
+       status.detail = NULL;
+       status.message = talloc_asprintf(handler,
+                       _("Booting in %d sec: %s"), sec, opt->option->name);
+
+       discover_server_notify_boot_status(handler->server, &status);
+
+       talloc_free(status.message);
+}
+
+static int default_timeout(void *arg)
+{
+       struct device_handler *handler = arg;
+       struct discover_boot_option *opt;
+
+       if (!handler->default_boot_option)
+               return 0;
+
+       if (handler->pending_boot)
+               return 0;
+
+       opt = handler->default_boot_option;
+
+       if (handler->sec_to_boot) {
+               countdown_status(handler, opt, handler->sec_to_boot);
+               handler->sec_to_boot--;
+               handler->timeout_waiter = waiter_register_timeout(
+                                               handler->waitset, 1000,
+                                               default_timeout, handler);
+               return 0;
+       }
+
+       handler->timeout_waiter = NULL;
+
+       pb_log("Timeout expired, booting default option %s\n", opt->option->id);
+
+       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 void setup_device_links(struct discover_context *ctx)
-{
-       struct link {
-               char *env, *dir;
-       } *link, links[] = {
-               {
-                       .env = "ID_FS_UUID",
-                       .dir = "disk/by-uuid"
-               },
-               {
-                       .env = "ID_FS_LABEL",
-                       .dir = "disk/by-label"
-               },
-               {
-                       .env = NULL
+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)
+{
+       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;
                }
-       };
 
-       for (link = links; link->env; link++) {
-               char *enc, *dir, *path;
-               const char *value;
+               return;
+       }
 
-               value = udev_event_param(ctx->event, link->env);
-               if (!value)
+       handler->sec_to_boot = config_get()->autoboot_timeout_sec;
+       handler->default_boot_option = opt;
+       handler->default_boot_option_priority = new_prio;
+
+       pb_log("handler: boot option %s set as default, timeout %u sec.\n",
+              opt->option->id, handler->sec_to_boot);
+
+       default_timeout(handler);
+}
+
+static bool resource_is_resolved(struct resource *res)
+{
+       return !res || res->resolved;
+}
+
+/* We only use this in an assert, which will disappear if we're compiling
+ * with NDEBUG, so we need the 'used' attribute for these builds */
+static bool __attribute__((used)) boot_option_is_resolved(
+               struct discover_boot_option *opt)
+{
+       return resource_is_resolved(opt->boot_image) &&
+               resource_is_resolved(opt->initrd) &&
+               resource_is_resolved(opt->dtb) &&
+               resource_is_resolved(opt->icon);
+}
+
+static bool resource_resolve(struct resource *res, const char *name,
+               struct discover_boot_option *opt,
+               struct device_handler *handler)
+{
+       struct parser *parser = opt->source;
+
+       if (resource_is_resolved(res))
+               return true;
+
+       pb_debug("Attempting to resolve resource %s->%s with parser %s\n",
+                       opt->option->id, name, parser->name);
+       parser->resolve_resource(handler, res);
+
+       return res->resolved;
+}
+
+static bool boot_option_resolve(struct discover_boot_option *opt,
+               struct device_handler *handler)
+{
+       return resource_resolve(opt->boot_image, "boot_image", opt, handler) &&
+               resource_resolve(opt->initrd, "initrd", opt, handler) &&
+               resource_resolve(opt->dtb, "dtb", opt, handler) &&
+               resource_resolve(opt->icon, "icon", opt, handler);
+}
+
+static void boot_option_finalise(struct device_handler *handler,
+               struct discover_boot_option *opt)
+{
+       assert(boot_option_is_resolved(opt));
+
+       /* check that the parsers haven't set any of the final data */
+       assert(!opt->option->boot_image_file);
+       assert(!opt->option->initrd_file);
+       assert(!opt->option->dtb_file);
+       assert(!opt->option->icon_file);
+       assert(!opt->option->device_id);
+
+       if (opt->boot_image)
+               opt->option->boot_image_file = opt->boot_image->url->full;
+       if (opt->initrd)
+               opt->option->initrd_file = opt->initrd->url->full;
+       if (opt->dtb)
+               opt->option->dtb_file = opt->dtb->url->full;
+       if (opt->icon)
+               opt->option->icon_file = opt->icon->url->full;
+
+       opt->option->device_id = opt->device->device->id;
+
+       if (opt->option->is_default)
+               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;
+
+       list_for_each_entry_safe(&handler->unresolved_boot_options,
+                       opt, tmp, list) {
+
+               pb_debug("queue: attempting resolution for %s\n",
+                               opt->option->id);
+
+               if (!boot_option_resolve(opt, handler))
                        continue;
 
-               enc = encode_label(ctx, value);
-               dir = join_paths(ctx, mount_base(), link->dir);
-               path = join_paths(ctx, dir, value);
-
-               if (!mkdir_recursive(dir)) {
-                       unlink(path);
-                       if (symlink(ctx->mount_path, path)) {
-                               pb_log("symlink(%s,%s): %s\n",
-                                               ctx->mount_path, path,
-                                               strerror(errno));
-                               talloc_free(path);
+               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);
+               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
+ */
+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;
+
+       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) {
+               list_remove(&opt->list);
+
+               if (boot_option_resolve(opt, handler)) {
+                       pb_log("boot option %s is resolved, "
+                                       "sending to clients\n",
+                                       opt->option->id);
+                       list_add_tail(&dev->boot_options, &opt->list);
+                       talloc_steal(dev, opt);
+                       boot_option_finalise(handler, opt);
+                       notify_boot_option(handler, opt);
+               } else {
+                       if (!opt->source->resolve_resource) {
+                               pb_log("parser %s gave us an unresolved "
+                                       "resource (%s), but no way to "
+                                       "resolve it\n",
+                                       opt->source->name, opt->option->id);
+                               talloc_free(opt);
                        } else {
-                               int i = ctx->n_links++;
-                               ctx->links = talloc_realloc(ctx,
-                                               ctx->links, char *,
-                                               ctx->n_links);
-                               ctx->links[i] = path;
+                               pb_log("boot option %s is unresolved, "
+                                               "adding to queue\n",
+                                               opt->option->id);
+                               list_add(&handler->unresolved_boot_options,
+                                               &opt->list);
+                               talloc_steal(handler, opt);
                        }
-
                }
+       }
+}
 
-               talloc_free(dir);
-               talloc_free(enc);
+void device_handler_add_device(struct device_handler *handler,
+               struct discover_device *device)
+{
+       handler->n_devices++;
+       handler->devices = talloc_realloc(handler, handler->devices,
+                               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);
+}
+
+void device_handler_add_ramdisk(struct device_handler *handler,
+               const char *path)
+{
+       struct ramdisk_device *dev;
+       unsigned int i;
+
+       if (!path)
+               return;
+
+       for (i = 0; i < handler->n_ramdisks; i++)
+               if (!strcmp(handler->ramdisks[i]->path, path))
+                       return;
+
+       dev = talloc_zero(handler, struct ramdisk_device);
+       if (!dev) {
+               pb_log("Failed to allocate memory to track %s\n", path);
+               return;
        }
+
+       dev->path = talloc_strdup(handler, path);
+
+       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;
+       }
+
+       handler->ramdisks[i] = dev;
+       i = handler->n_ramdisks++;
 }
 
-static int mount_device(struct discover_context *ctx)
+struct ramdisk_device *device_handler_get_ramdisk(
+               struct device_handler *handler)
 {
-       const char *mountpoint;
-       struct stat statbuf;
-       int status;
-       pid_t pid;
+       unsigned int i;
+       char *name;
+       dev_t id;
 
-       if (!ctx->mount_path) {
-               mountpoint = mountpoint_for_device(ctx->device_path);
-               ctx->mount_path = talloc_strdup(ctx, mountpoint);
+       /* 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;
        }
 
-       if (stat(ctx->mount_path, &statbuf)) {
-               if (mkdir(ctx->mount_path, 0755)) {
-                       pb_log("couldn't create mount directory %s: %s\n",
-                                       ctx->mount_path, strerror(errno));
-                       return -1;
+       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 handler->ramdisks[i];
+}
+
+void device_handler_release_ramdisk(struct discover_device *device)
+{
+       struct ramdisk_device *ramdisk = device->ramdisk;
+
+       talloc_free(ramdisk->snapshot);
+       talloc_free(ramdisk->origin);
+       talloc_free(ramdisk->base);
+
+       ramdisk->snapshot = ramdisk->origin = ramdisk->base = NULL;
+       ramdisk->sectors = 0;
+
+       device->ramdisk = NULL;
+}
+
+/* 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 boot_status *status;
+       int rc;
+
+       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);
+
+       /* create our context */
+       ctx = device_handler_discover_context_create(handler, 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);
+
+       /* 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;
+}
+
+/* Incoming dhcp event */
+int device_handler_dhcp(struct device_handler *handler,
+               struct discover_device *dev, struct event *event)
+{
+       struct discover_context *ctx;
+       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);
+
+       /* create our context */
+       ctx = device_handler_discover_context_create(handler, dev);
+       ctx->event = event;
+
+       iterate_parsers(ctx);
+
+       device_handler_discover_context_commit(handler, ctx);
+
+       /*
+        * 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);
+
+       talloc_free(status);
+       talloc_free(ctx);
+
+       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;
+       struct boot_status *status;
+
+       status = talloc_zero(handler, struct boot_status);
+       status->type = BOOT_STATUS_INFO;
+       status->message = talloc_asprintf(status, _("Processing user config"));
+       boot_status(handler, status);
+
+       /* 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);
+
+       status->message = talloc_asprintf(status,
+                               _("Processing user config complete"));
+       boot_status(handler, status);
+
+       talloc_free(status);
+       talloc_free(ctx);
+
+       return 0;
+}
+
+static struct discover_boot_option *find_boot_option_by_id(
+               struct device_handler *handler, const char *id)
+{
+       unsigned int i;
+
+       for (i = 0; i < handler->n_devices; i++) {
+               struct discover_device *dev = handler->devices[i];
+               struct discover_boot_option *opt;
+
+               list_for_each_entry(&dev->boot_options, opt, list)
+                       if (!strcmp(opt->option->id, id))
+                               return opt;
+       }
+
+       return NULL;
+}
+
+void device_handler_boot(struct device_handler *handler,
+               struct boot_command *cmd)
+{
+       struct discover_boot_option *opt = NULL;
+
+       if (cmd->option_id && strlen(cmd->option_id))
+               opt = find_boot_option_by_id(handler, cmd->option_id);
+
+       if (handler->pending_boot)
+               boot_cancel(handler->pending_boot);
+
+       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)
+{
+       struct boot_status status;
+
+       if (handler->timeout_waiter)
+               waiter_remove(handler->timeout_waiter);
+
+       handler->timeout_waiter = NULL;
+       handler->autoboot_enabled = false;
+
+       /* we only send status if we had a default boot option queued */
+       if (!handler->default_boot_option)
+               return;
+
+       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");
+
+       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 {
-               if (!S_ISDIR(statbuf.st_mode)) {
-                       pb_log("mountpoint %s exists, but isn't a directory\n",
-                                       ctx->mount_path);
-                       return -1;
+               /* 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);
        }
 
-       pid = fork();
-       if (pid == -1) {
-               pb_log("%s: fork failed: %s\n", __func__, strerror(errno));
-               return -1;
+       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;
        }
 
-       if (pid == 0) {
-               execl(MOUNT_BIN, MOUNT_BIN, ctx->device_path, ctx->mount_path,
-                               "-o", "ro", NULL);
-               exit(EXIT_FAILURE);
+       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);
        }
 
-       if (waitpid(pid, &status, 0) == -1) {
-               pb_log("%s: waitpid failed: %s\n", __func__,
-                               strerror(errno));
-               return -1;
+       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;
        }
 
-       if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
+       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;
 
-       setup_device_links(ctx);
        return 0;
 }
 
-static int handle_add_event(struct device_handler *handler,
-               struct udev_event *event)
+static void device_handler_reinit_sources(struct device_handler *handler)
 {
-       struct discover_context *ctx;
-       const char *devname;
+       /* 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;
 
-       /* create our context */
-       ctx = talloc(NULL, struct discover_context);
-       ctx->event = event;
-       ctx->mount_path = NULL;
-       ctx->links = NULL;
-       ctx->n_links = 0;
+       device_path = get_device_path(dev);
 
-       devname = udev_event_param(ctx->event, "DEVNAME");
-       if (!devname) {
-               pb_log("no devname for %s?\n", event->device);
+       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");
        }
 
-       ctx->device_path = talloc_strdup(ctx, devname);
+       dev->mount_path = join_paths(dev, mount_base(),
+                                       dev->device_path);
 
-       rc = mount_device(ctx);
-       if (rc) {
-               pb_log("mount_device failed for %s\n", event->device);
-               talloc_free(ctx);
+       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;
        }
 
-       talloc_free(ctx);
+       pb_log("couldn't mount device %s: mount failed: %s\n",
+                       device_path, strerror(errno));
 
-       return 0;
+       /* 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 handle_remove_event(struct device_handler *handler,
-               struct udev_event *event)
+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_handler_event(struct device_handler *handler,
-               struct udev_event *event)
+int device_request_write(struct discover_device *dev, bool *release)
 {
+       const char *fstype, *device_path;
+       const struct config *config;
        int rc;
 
-       switch (event->action) {
-       case UDEV_ACTION_ADD:
-               rc = handle_add_event(handler, event);
-               break;
+       *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);
 
-       case UDEV_ACTION_REMOVE:
-               rc = handle_remove_event(handler, event);
-               break;
+       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;
        }
 
-       return rc;
+       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;
 }
 
-struct device_handler *device_handler_init(struct discover_server *server)
+void device_release_write(struct discover_device *dev, bool release)
 {
-       struct device_handler *handler;
+       const char *fstype, *device_path;
 
-       handler = talloc(NULL, struct device_handler);
-       handler->devices = NULL;
-       handler->n_devices = 0;
+       if (!release)
+               return;
 
-       /* set up our mount point base */
-       mkdir_recursive(mount_base());
+       device_path = get_device_path(dev);
 
-       return handler;
+       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;
 }
 
-void device_handler_destroy(struct device_handler *devices)
+static void device_handler_reinit_sources(
+               struct device_handler *handler __attribute__((unused)))
 {
-       talloc_free(devices);
 }
 
+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
+