]> git.ozlabs.org Git - petitboot/blobdiff - discover/device-handler.c
Make read-only guarantee user-settable
[petitboot] / discover / device-handler.c
index 487f2e73506221a316cd8e3b72928cccc733b167..4f7a7b7500c4fee446747df10861095d30b2ce33 100644 (file)
@@ -26,6 +26,7 @@
 
 #include "device-handler.h"
 #include "discover-server.h"
+#include "devmapper.h"
 #include "user-event.h"
 #include "platform.h"
 #include "event.h"
@@ -56,6 +57,9 @@ struct device_handler {
        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;
@@ -319,6 +323,7 @@ struct device_handler *device_handler_init(struct discover_server *server,
 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);
@@ -330,13 +335,20 @@ void device_handler_reinit(struct device_handler *handler)
        list_init(&handler->unresolved_boot_options);
 
        /* drop all devices */
-       for (i = 0; i < handler->n_devices; i++)
+       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);
 }
@@ -748,6 +760,95 @@ void device_handler_add_device(struct device_handler *handler,
                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++;
+}
+
+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;
+       }
+
+       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.
  */
@@ -755,8 +856,16 @@ 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;
+       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 */
@@ -777,6 +886,11 @@ int device_handler_discover(struct device_handler *handler,
        device_handler_discover_context_commit(handler, ctx);
 
 out:
+       status->message = talloc_asprintf(status,"Processing %s complete\n",
+                               dev->device->id);
+       boot_status(handler, status);
+
+       talloc_free(status);
        talloc_free(ctx);
 
        return 0;
@@ -787,6 +901,13 @@ 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;
+       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);
@@ -796,6 +917,11 @@ int device_handler_dhcp(struct device_handler *handler,
 
        device_handler_discover_context_commit(handler, ctx);
 
+       status->message = talloc_asprintf(status,"Processing %s complete\n",
+                               dev->device->id);
+       boot_status(handler, status);
+
+       talloc_free(status);
        talloc_free(ctx);
 
        return 0;
@@ -805,19 +931,30 @@ int device_handler_dhcp(struct device_handler *handler,
 int device_handler_conf(struct device_handler *handler,
                struct discover_device *dev, struct pb_url *url)
 {
-        struct discover_context *ctx;
+       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;
 
-        /* create our context */
-        ctx = device_handler_discover_context_create(handler, dev);
-        ctx->conf_url = url;
+       iterate_parsers(ctx);
 
-        iterate_parsers(ctx);
+       device_handler_discover_context_commit(handler, ctx);
 
-        device_handler_discover_context_commit(handler, ctx);
+       status->message = talloc_asprintf(status,
+                               "Processing user config complete");
+       boot_status(handler, status);
 
-        talloc_free(ctx);
+       talloc_free(status);
+       talloc_free(ctx);
 
-        return 0;
+       return 0;
 }
 
 static struct discover_boot_option *find_boot_option_by_id(
@@ -1101,14 +1238,22 @@ static const char *fs_parameters(unsigned int rw_flags, const char *fstype)
        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;
 
-       rc = stat(dev->device_path, &devstat);
+       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;
@@ -1158,7 +1303,7 @@ static bool check_existing_mount(struct discover_device *dev)
 
 static int mount_device(struct discover_device *dev)
 {
-       const char *fstype;
+       const char *fstype, *device_path;
        int rc;
 
        if (!dev->device_path)
@@ -1190,9 +1335,11 @@ static int mount_device(struct discover_device *dev)
                goto err_free;
        }
 
+       device_path = get_device_path(dev);
+
        pb_log("mounting device %s read-only\n", dev->device_path);
        errno = 0;
-       rc = mount(dev->device_path, dev->mount_path, fstype,
+       rc = mount(device_path, dev->mount_path, fstype,
                        MS_RDONLY | MS_SILENT,
                        fs_parameters(MS_RDONLY, fstype));
        if (!rc) {
@@ -1203,7 +1350,10 @@ static int mount_device(struct discover_device *dev)
        }
 
        pb_log("couldn't mount device %s: mount failed: %s\n",
-                       dev->device_path, strerror(errno));
+                       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:
@@ -1214,17 +1364,21 @@ err_free:
 
 static int umount_device(struct discover_device *dev)
 {
+       const char *device_path;
        int rc;
 
        if (!dev->mounted || !dev->unmount)
                return 0;
 
-       pb_log("unmounting device %s\n", dev->device_path);
+       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);
 
@@ -1236,11 +1390,16 @@ static int umount_device(struct discover_device *dev)
 
 int device_request_write(struct discover_device *dev, bool *release)
 {
-       const char *fstype;
+       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;
 
@@ -1249,14 +1408,18 @@ int device_request_write(struct discover_device *dev, bool *release)
 
        fstype = discover_device_get_param(dev, "ID_FS_TYPE");
 
-       pb_log("remounting device %s read-write\n", dev->device_path);
+       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\n", dev->mount_path);
+               pb_log("Failed to unmount %s: %s\n",
+                      dev->mount_path, strerror(errno));
                return -1;
        }
-       rc = mount(dev->device_path, dev->mount_path, fstype,
+
+       rc = mount(device_path, dev->mount_path, fstype,
                        MS_SILENT,
                        fs_parameters(MS_REMOUNT, fstype));
        if (rc)
@@ -1267,29 +1430,50 @@ int device_request_write(struct discover_device *dev, bool *release)
        return 0;
 
 mount_ro:
-       pb_log("Unable to remount device %s read-write\n", dev->device_path);
-       rc = mount(dev->device_path, dev->mount_path, fstype,
+       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(MS_RDONLY, fstype));
-       if (rc)
-               pb_log("Unable to recover mount for %s\n", dev->device_path);
+                       fs_parameters(MS_RDONLY, fstype)))
+               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;
+       const char *fstype, *device_path;
+       int rc = 0;
 
        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", dev->device_path);
-       mount(dev->device_path, dev->mount_path, "",
-                       MS_REMOUNT | MS_RDONLY | MS_SILENT,
+       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);
+       }
+
+       mount(device_path, dev->mount_path, fstype,
+                       MS_RDONLY | MS_SILENT,
                        fs_parameters(MS_RDONLY, fstype));
-       dev->mounted_rw = false;
+       if (rc)
+               pb_log("Failed to remount %s read-only: %s\n",
+                      device_path, strerror(errno));
+       else
+               dev->mounted = true;
 }
 
 #else