/* * Copyright (C) 2001, 2002 Sistina Software (UK) Limited. * Copyright (C) 2004 - 2006 Red Hat, Inc. All rights reserved. * * This file is released under the GPL. */ #include "dm.h" #include #include #include #include #include #include #include #include #include #include #define DM_MSG_PREFIX "ioctl" #define DM_DRIVER_EMAIL "dm-devel@redhat.com" /*----------------------------------------------------------------- * The ioctl interface needs to be able to look up devices by * name or uuid. *---------------------------------------------------------------*/ struct hash_cell { struct list_head name_list; struct list_head uuid_list; char *name; char *uuid; struct mapped_device *md; struct dm_table *new_map; }; /* * A dummy definition to make RCU happy. * struct dm_table should never be dereferenced in this file. */ struct dm_table { int undefined__; }; struct vers_iter { size_t param_size; struct dm_target_versions *vers, *old_vers; char *end; uint32_t flags; }; #define NUM_BUCKETS 64 #define MASK_BUCKETS (NUM_BUCKETS - 1) static struct list_head _name_buckets[NUM_BUCKETS]; static struct list_head _uuid_buckets[NUM_BUCKETS]; static void dm_hash_remove_all(int keep_open_devices); /* * Guards access to both hash tables. */ static DECLARE_RWSEM(_hash_lock); /* * Protects use of mdptr to obtain hash cell name and uuid from mapped device. */ static DEFINE_MUTEX(dm_hash_cells_mutex); static void init_buckets(struct list_head *buckets) { unsigned int i; for (i = 0; i < NUM_BUCKETS; i++) INIT_LIST_HEAD(buckets + i); } static int dm_hash_init(void) { init_buckets(_name_buckets); init_buckets(_uuid_buckets); return 0; } static void dm_hash_exit(void) { dm_hash_remove_all(0); } /*----------------------------------------------------------------- * Hash function: * We're not really concerned with the str hash function being * fast since it's only used by the ioctl interface. *---------------------------------------------------------------*/ static unsigned int hash_str(const char *str) { const unsigned int hash_mult = 2654435387U; unsigned int h = 0; while (*str) h = (h + (unsigned int) *str++) * hash_mult; return h & MASK_BUCKETS; } /*----------------------------------------------------------------- * Code for looking up a device by name *---------------------------------------------------------------*/ static struct hash_cell *__get_name_cell(const char *str) { struct hash_cell *hc; unsigned int h = hash_str(str); list_for_each_entry (hc, _name_buckets + h, name_list) if (!strcmp(hc->name, str)) { dm_get(hc->md); return hc; } return NULL; } static struct hash_cell *__get_uuid_cell(const char *str) { struct hash_cell *hc; unsigned int h = hash_str(str); list_for_each_entry (hc, _uuid_buckets + h, uuid_list) if (!strcmp(hc->uuid, str)) { dm_get(hc->md); return hc; } return NULL; } static struct hash_cell *__get_dev_cell(uint64_t dev) { struct mapped_device *md; struct hash_cell *hc; md = dm_get_md(huge_decode_dev(dev)); if (!md) return NULL; hc = dm_get_mdptr(md); if (!hc) { dm_put(md); return NULL; } return hc; } /*----------------------------------------------------------------- * Inserting, removing and renaming a device. *---------------------------------------------------------------*/ static struct hash_cell *alloc_cell(const char *name, const char *uuid, struct mapped_device *md) { struct hash_cell *hc; hc = kmalloc(sizeof(*hc), GFP_KERNEL); if (!hc) return NULL; hc->name = kstrdup(name, GFP_KERNEL); if (!hc->name) { kfree(hc); return NULL; } if (!uuid) hc->uuid = NULL; else { hc->uuid = kstrdup(uuid, GFP_KERNEL); if (!hc->uuid) { kfree(hc->name); kfree(hc); return NULL; } } INIT_LIST_HEAD(&hc->name_list); INIT_LIST_HEAD(&hc->uuid_list); hc->md = md; hc->new_map = NULL; return hc; } static void free_cell(struct hash_cell *hc) { if (hc) { kfree(hc->name); kfree(hc->uuid); kfree(hc); } } /* * The kdev_t and uuid of a device can never change once it is * initially inserted. */ static int dm_hash_insert(const char *name, const char *uuid, struct mapped_device *md) { struct hash_cell *cell, *hc; /* * Allocate the new cells. */ cell = alloc_cell(name, uuid, md); if (!cell) return -ENOMEM; /* * Insert the cell into both hash tables. */ down_write(&_hash_lock); hc = __get_name_cell(name); if (hc) { dm_put(hc->md); goto bad; } list_add(&cell->name_list, _name_buckets + hash_str(name)); if (uuid) { hc = __get_uuid_cell(uuid); if (hc) { list_del(&cell->name_list); dm_put(hc->md); goto bad; } list_add(&cell->uuid_list, _uuid_buckets + hash_str(uuid)); } dm_get(md); mutex_lock(&dm_hash_cells_mutex); dm_set_mdptr(md, cell); mutex_unlock(&dm_hash_cells_mutex); up_write(&_hash_lock); return 0; bad: up_write(&_hash_lock); free_cell(cell); return -EBUSY; } static struct dm_table *__hash_remove(struct hash_cell *hc) { struct dm_table *table; int srcu_idx; /* remove from the dev hash */ list_del(&hc->uuid_list); list_del(&hc->name_list); mutex_lock(&dm_hash_cells_mutex); dm_set_mdptr(hc->md, NULL); mutex_unlock(&dm_hash_cells_mutex); table = dm_get_live_table(hc->md, &srcu_idx); if (table) dm_table_event(table); dm_put_live_table(hc->md, srcu_idx); table = NULL; if (hc->new_map) table = hc->new_map; dm_put(hc->md); free_cell(hc); return table; } static void dm_hash_remove_all(int keep_open_devices) { int i, dev_skipped; struct hash_cell *hc; struct mapped_device *md; struct dm_table *t; retry: dev_skipped = 0; down_write(&_hash_lock); for (i = 0; i < NUM_BUCKETS; i++) { list_for_each_entry(hc, _name_buckets + i, name_list) { md = hc->md; dm_get(md); if (keep_open_devices && dm_lock_for_deletion(md)) { dm_put(md); dev_skipped++; continue; } t = __hash_remove(hc); up_write(&_hash_lock); if (t) { dm_sync_table(md); dm_table_destroy(t); } dm_put(md); if (likely(keep_open_devices)) dm_destroy(md); else dm_destroy_immediate(md); /* * Some mapped devices may be using other mapped * devices, so repeat until we make no further * progress. If a new mapped device is created * here it will also get removed. */ goto retry; } } up_write(&_hash_lock); if (dev_skipped) DMWARN("remove_all left %d open device(s)", dev_skipped); } /* * Set the uuid of a hash_cell that isn't already set. */ static void __set_cell_uuid(struct hash_cell *hc, char *new_uuid) { mutex_lock(&dm_hash_cells_mutex); hc->uuid = new_uuid; mutex_unlock(&dm_hash_cells_mutex); list_add(&hc->uuid_list, _uuid_buckets + hash_str(new_uuid)); } /* * Changes the name of a hash_cell and returns the old name for * the caller to free. */ static char *__change_cell_name(struct hash_cell *hc, char *new_name) { char *old_name; /* * Rename and move the name cell. */ list_del(&hc->name_list); old_name = hc->name; mutex_lock(&dm_hash_cells_mutex); hc->name = new_name; mutex_unlock(&dm_hash_cells_mutex); list_add(&hc->name_list, _name_buckets + hash_str(new_name)); return old_name; } static struct mapped_device *dm_hash_rename(struct dm_ioctl *param, const char *new) { char *new_data, *old_name = NULL; struct hash_cell *hc; struct dm_table *table; struct mapped_device *md; unsigned change_uuid = (param->flags & DM_UUID_FLAG) ? 1 : 0; int srcu_idx; /* * duplicate new. */ new_data = kstrdup(new, GFP_KERNEL); if (!new_data) return ERR_PTR(-ENOMEM); down_write(&_hash_lock); /* * Is new free ? */ if (change_uuid) hc = __get_uuid_cell(new); else hc = __get_name_cell(new); if (hc) { DMWARN("Unable to change %s on mapped device %s to one that " "already exists: %s", change_uuid ? "uuid" : "name", param->name, new); dm_put(hc->md); up_write(&_hash_lock); kfree(new_data); return ERR_PTR(-EBUSY); } /* * Is there such a device as 'old' ? */ hc = __get_name_cell(param->name); if (!hc) { DMWARN("Unable to rename non-existent device, %s to %s%s", param->name, change_uuid ? "uuid " : "", new); up_write(&_hash_lock); kfree(new_data); return ERR_PTR(-ENXIO); } /* * Does this device already have a uuid? */ if (change_uuid && hc->uuid) { DMWARN("Unable to change uuid of mapped device %s to %s " "because uuid is already set to %s", param->name, new, hc->uuid); dm_put(hc->md); up_write(&_hash_lock); kfree(new_data); return ERR_PTR(-EINVAL); } if (change_uuid) __set_cell_uuid(hc, new_data); else old_name = __change_cell_name(hc, new_data); /* * Wake up any dm event waiters. */ table = dm_get_live_table(hc->md, &srcu_idx); if (table) dm_table_event(table); dm_put_live_table(hc->md, srcu_idx); if (!dm_kobject_uevent(hc->md, KOBJ_CHANGE, param->event_nr)) param->flags |= DM_UEVENT_GENERATED_FLAG; md = hc->md; up_write(&_hash_lock); kfree(old_name); return md; } /*----------------------------------------------------------------- * Implementation of the ioctl commands *---------------------------------------------------------------*/ /* * All the ioctl commands get dispatched to functions with this * prototype. */ typedef int (*ioctl_fn)(struct dm_ioctl *param, size_t param_size); static int remove_all(struct dm_ioctl *param, size_t param_size) { dm_hash_remove_all(1); param->data_size = 0; return 0; } /* * Round up the ptr to an 8-byte boundary. */ #define ALIGN_MASK 7 static inline void *align_ptr(void *ptr) { return (void *) (((size_t) (ptr + ALIGN_MASK)) & ~ALIGN_MASK); } /* * Retrieves the data payload buffer from an already allocated * struct dm_ioctl. */ static void *get_result_buffer(struct dm_ioctl *param, size_t param_size, size_t *len) { param->data_start = align_ptr(param + 1) - (void *) param; if (param->data_start < param_size) *len = param_size - param->data_start; else *len = 0; return ((void *) param) + param->data_start; } static int list_devices(struct dm_ioctl *param, size_t param_size) { unsigned int i; struct hash_cell *hc; size_t len, needed = 0; struct gendisk *disk; struct dm_name_list *nl, *old_nl = NULL; down_write(&_hash_lock); /* * Loop through all the devices working out how much * space we need. */ for (i = 0; i < NUM_BUCKETS; i++) { list_for_each_entry (hc, _name_buckets + i, name_list) { needed += sizeof(struct dm_name_list); needed += strlen(hc->name) + 1; needed += ALIGN_MASK; } } /* * Grab our output buffer. */ nl = get_result_buffer(param, param_size, &len); if (len < needed) { param->flags |= DM_BUFFER_FULL_FLAG; goto out; } param->data_size = param->data_start + needed; nl->dev = 0; /* Flags no data */ /* * Now loop through filling out the names. */ for (i = 0; i < NUM_BUCKETS; i++) { list_for_each_entry (hc, _name_buckets + i, name_list) { if (old_nl) old_nl->next = (uint32_t) ((void *) nl - (void *) old_nl); disk = dm_disk(hc->md); nl->dev = huge_encode_dev(disk_devt(disk)); nl->next = 0; strcpy(nl->name, hc->name); old_nl = nl; nl = align_ptr(((void *) ++nl) + strlen(hc->name) + 1); } } out: up_write(&_hash_lock); return 0; } static void list_version_get_needed(struct target_type *tt, void *needed_param) { size_t *needed = needed_param; *needed += sizeof(struct dm_target_versions); *needed += strlen(tt->name); *needed += ALIGN_MASK; } static void list_version_get_info(struct target_type *tt, void *param) { struct vers_iter *info = param; /* Check space - it might have changed since the first iteration */ if ((char *)info->vers + sizeof(tt->version) + strlen(tt->name) + 1 > info->end) { info->flags = DM_BUFFER_FULL_FLAG; return; } if (info->old_vers) info->old_vers->next = (uint32_t) ((void *)info->vers - (void *)info->old_vers); info->vers->version[0] = tt->version[0]; info->vers->version[1] = tt->version[1]; info->vers->version[2] = tt->version[2]; info->vers->next = 0; strcpy(info->vers->name, tt->name); info->old_vers = info->vers; info->vers = align_ptr(((void *) ++info->vers) + strlen(tt->name) + 1); } static int list_versions(struct dm_ioctl *param, size_t param_size) { size_t len, needed = 0; struct dm_target_versions *vers; struct vers_iter iter_info; /* * Loop through all the devices working out how much * space we need. */ dm_target_iterate(list_version_get_needed, &needed); /* * Grab our output buffer. */ vers = get_result_buffer(param, param_size, &len); if (len < needed) { param->flags |= DM_BUFFER_FULL_FLAG; goto out; } param->data_size = param->data_start + needed; iter_info.param_size = param_size; iter_info.old_vers = NULL; iter_info.vers = vers; iter_info.flags = 0; iter_info.end = (char *)vers+len; /* * Now loop through filling out the names & versions. */ dm_target_iterate(list_version_get_info, &iter_info); param->flags |= iter_info.flags; out: return 0; } static int check_name(const char *name) { if (strchr(name, '/')) { DMWARN("invalid device name"); return -EINVAL; } return 0; } /* * On successful return, the caller must not attempt to acquire * _hash_lock without first calling dm_table_put, because dm_table_destroy * waits for this dm_table_put and could be called under this lock. */ static struct dm_table *dm_get_inactive_table(struct mapped_device *md, int *srcu_idx) { struct hash_cell *hc; struct dm_table *table = NULL; /* increment rcu count, we don't care about the table pointer */ dm_get_live_table(md, srcu_idx); down_read(&_hash_lock); hc = dm_get_mdptr(md); if (!hc || hc->md != md) { DMWARN("device has been removed from the dev hash table."); goto out; } table = hc->new_map; out: up_read(&_hash_lock); return table; } static struct dm_table *dm_get_live_or_inactive_table(struct mapped_device *md, struct dm_ioctl *param, int *srcu_idx) { return (param->flags & DM_QUERY_INACTIVE_TABLE_FLAG) ? dm_get_inactive_table(md, srcu_idx) : dm_get_live_table(md, srcu_idx); } /* * Fills in a dm_ioctl structure, ready for sending back to * userland. */ static void __dev_status(struct mapped_device *md, struct dm_ioctl *param) { struct gendisk *disk = dm_disk(md); struct dm_table *table; int srcu_idx; param->flags &= ~(DM_SUSPEND_FLAG | DM_READONLY_FLAG | DM_ACTIVE_PRESENT_FLAG); if (dm_suspended_md(md)) param->flags |= DM_SUSPEND_FLAG; param->dev = huge_encode_dev(disk_devt(disk)); /* * Yes, this will be out of date by the time it gets back * to userland, but it is still very useful for * debugging. */ param->open_count = dm_open_count(md); param->event_nr = dm_get_event_nr(md); param->target_count = 0; table = dm_get_live_table(md, &srcu_idx); if (table) { if (!(param->flags & DM_QUERY_INACTIVE_TABLE_FLAG)) { if (get_disk_ro(disk)) param->flags |= DM_READONLY_FLAG; param->target_count = dm_table_get_num_targets(table); } param->flags |= DM_ACTIVE_PRESENT_FLAG; } dm_put_live_table(md, srcu_idx); if (param->flags & DM_QUERY_INACTIVE_TABLE_FLAG) { int srcu_idx; table = dm_get_inactive_table(md, &srcu_idx); if (table) { if (!(dm_table_get_mode(table) & FMODE_WRITE)) param->flags |= DM_READONLY_FLAG; param->target_count = dm_table_get_num_targets(table); } dm_put_live_table(md, srcu_idx); } } static int dev_create(struct dm_ioctl *param, size_t param_size) { int r, m = DM_ANY_MINOR; struct mapped_device *md; r = check_name(param->name); if (r) return r; if (param->flags & DM_PERSISTENT_DEV_FLAG) m = MINOR(huge_decode_dev(param->dev)); r = dm_create(m, &md); if (r) return r; r = dm_hash_insert(param->name, *param->uuid ? param->uuid : NULL, md); if (r) { dm_put(md); dm_destroy(md); return r; } param->flags &= ~DM_INACTIVE_PRESENT_FLAG; __dev_status(md, param); dm_put(md); return 0; } /* * Always use UUID for lookups if it's present, otherwise use name or dev. */ static struct hash_cell *__find_device_hash_cell(struct dm_ioctl *param) { struct hash_cell *hc = NULL; if (*param->uuid) { if (*param->name || param->dev) return NULL; hc = __get_uuid_cell(param->uuid); if (!hc) return NULL; } else if (*param->name) { if (param->dev) return NULL; hc = __get_name_cell(param->name); if (!hc) return NULL; } else if (param->dev) { hc = __get_dev_cell(param->dev); if (!hc) return NULL; } else return NULL; /* * Sneakily write in both the name and the uuid * while we have the cell. */ strlcpy(param->name, hc->name, sizeof(param->name)); if (hc->uuid) strlcpy(param->uuid, hc->uuid, sizeof(param->uuid)); else param->uuid[0] = '\0'; if (hc->new_map) param->flags |= DM_INACTIVE_PRESENT_FLAG; else param->flags &= ~DM_INACTIVE_PRESENT_FLAG; return hc; } static struct mapped_device *find_device(struct dm_ioctl *param) { struct hash_cell *hc; struct mapped_device *md = NULL; down_read(&_hash_lock); hc = __find_device_hash_cell(param); if (hc) md = hc->md; up_read(&_hash_lock); return md; } static int dev_remove(struct dm_ioctl *param, size_t param_size) { struct hash_cell *hc; struct mapped_device *md; int r; struct dm_table *t; down_write(&_hash_lock); hc = __find_device_hash_cell(param); if (!hc) { DMDEBUG_LIMIT("device doesn't appear to be in the dev hash table."); up_write(&_hash_lock); return -ENXIO; } md = hc->md; /* * Ensure the device is not open and nothing further can open it. */ r = dm_lock_for_deletion(md); if (r) { DMDEBUG_LIMIT("unable to remove open device %s", hc->name); up_write(&_hash_lock); dm_put(md); return r; } t = __hash_remove(hc); up_write(&_hash_lock); if (t) { dm_sync_table(md); dm_table_destroy(t); } if (!dm_kobject_uevent(md, KOBJ_REMOVE, param->event_nr)) param->flags |= DM_UEVENT_GENERATED_FLAG; dm_put(md); dm_destroy(md); return 0; } /* * Check a string doesn't overrun the chunk of * memory we copied from userland. */ static int invalid_str(char *str, void *end) { while ((void *) str < end) if (!*str++) return 0; return -EINVAL; } static int dev_rename(struct dm_ioctl *param, size_t param_size) { int r; char *new_data = (char *) param + param->data_start; struct mapped_device *md; unsigned change_uuid = (param->flags & DM_UUID_FLAG) ? 1 : 0; if (new_data < param->data || invalid_str(new_data, (void *) param + param_size) || !*new_data || strlen(new_data) > (change_uuid ? DM_UUID_LEN - 1 : DM_NAME_LEN - 1)) { DMWARN("Invalid new mapped device name or uuid string supplied."); return -EINVAL; } if (!change_uuid) { r = check_name(new_data); if (r) return r; } md = dm_hash_rename(param, new_data); if (IS_ERR(md)) return PTR_ERR(md); __dev_status(md, param); dm_put(md); return 0; } static int dev_set_geometry(struct dm_ioctl *param, size_t param_size) { int r = -EINVAL, x; struct mapped_device *md; struct hd_geometry geometry; unsigned long indata[4]; char *geostr = (char *) param + param->data_start; char dummy; md = find_device(param); if (!md) return -ENXIO; if (geostr < param->data || invalid_str(geostr, (void *) param + param_size)) { DMWARN("Invalid geometry supplied."); goto out; } x = sscanf(geostr, "%lu %lu %lu %lu%c", indata, indata + 1, indata + 2, indata + 3, &dummy); if (x != 4) { DMWARN("Unable to interpret geometry settings."); goto out; } if (indata[0] > 65535 || indata[1] > 255 || indata[2] > 255 || indata[3] > ULONG_MAX) { DMWARN("Geometry exceeds range limits."); goto out; } geometry.cylinders = indata[0]; geometry.heads = indata[1]; geometry.sectors = indata[2]; geometry.start = indata[3]; r = dm_set_geometry(md, &geometry); param->data_size = 0; out: dm_put(md); return r; } static int do_suspend(struct dm_ioctl *param) { int r = 0; unsigned suspend_flags = DM_SUSPEND_LOCKFS_FLAG; struct mapped_device *md; md = find_device(param); if (!md) return -ENXIO; if (param->flags & DM_SKIP_LOCKFS_FLAG) suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG; if (param->flags & DM_NOFLUSH_FLAG) suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG; if (!dm_suspended_md(md)) { r = dm_suspend(md, suspend_flags); if (r) goto out; } __dev_status(md, param); out: dm_put(md); return r; } static int do_resume(struct dm_ioctl *param) { int r = 0; unsigned suspend_flags = DM_SUSPEND_LOCKFS_FLAG; struct hash_cell *hc; struct mapped_device *md; struct dm_table *new_map, *old_map = NULL; down_write(&_hash_lock); hc = __find_device_hash_cell(param); if (!hc) { DMDEBUG_LIMIT("device doesn't appear to be in the dev hash table."); up_write(&_hash_lock); return -ENXIO; } md = hc->md; new_map = hc->new_map; hc->new_map = NULL; param->flags &= ~DM_INACTIVE_PRESENT_FLAG; up_write(&_hash_lock); /* Do we need to load a new map ? */ if (new_map) { /* Suspend if it isn't already suspended */ if (param->flags & DM_SKIP_LOCKFS_FLAG) suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG; if (param->flags & DM_NOFLUSH_FLAG) suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG; if (!dm_suspended_md(md)) dm_suspend(md, suspend_flags); old_map = dm_swap_table(md, new_map); if (IS_ERR(old_map)) { dm_sync_table(md); dm_table_destroy(new_map); dm_put(md); return PTR_ERR(old_map); } if (dm_table_get_mode(new_map) & FMODE_WRITE) set_disk_ro(dm_disk(md), 0); else set_disk_ro(dm_disk(md), 1); } if (dm_suspended_md(md)) { r = dm_resume(md); if (!r && !dm_kobject_uevent(md, KOBJ_CHANGE, param->event_nr)) param->flags |= DM_UEVENT_GENERATED_FLAG; } /* * Since dm_swap_table synchronizes RCU, nobody should be in * read-side critical section already. */ if (old_map) dm_table_destroy(old_map); if (!r) __dev_status(md, param); dm_put(md); return r; } /* * Set or unset the suspension state of a device. * If the device already is in the requested state we just return its status. */ static int dev_suspend(struct dm_ioctl *param, size_t param_size) { if (param->flags & DM_SUSPEND_FLAG) return do_suspend(param); return do_resume(param); } /* * Copies device info back to user space, used by * the create and info ioctls. */ static int dev_status(struct dm_ioctl *param, size_t param_size) { struct mapped_device *md; md = find_device(param); if (!md) return -ENXIO; __dev_status(md, param); dm_put(md); return 0; } /* * Build up the status struct for each target */ static void retrieve_status(struct dm_table *table, struct dm_ioctl *param, size_t param_size) { unsigned int i, num_targets; struct dm_target_spec *spec; char *outbuf, *outptr; status_type_t type; size_t remaining, len, used = 0; unsigned status_flags = 0; outptr = outbuf = get_result_buffer(param, param_size, &len); if (param->flags & DM_STATUS_TABLE_FLAG) type = STATUSTYPE_TABLE; else type = STATUSTYPE_INFO; /* Get all the target info */ num_targets = dm_table_get_num_targets(table); for (i = 0; i < num_targets; i++) { struct dm_target *ti = dm_table_get_target(table, i); size_t l; remaining = len - (outptr - outbuf); if (remaining <= sizeof(struct dm_target_spec)) { param->flags |= DM_BUFFER_FULL_FLAG; break; } spec = (struct dm_target_spec *) outptr; spec->status = 0; spec->sector_start = ti->begin; spec->length = ti->len; strncpy(spec->target_type, ti->type->name, sizeof(spec->target_type)); outptr += sizeof(struct dm_target_spec); remaining = len - (outptr - outbuf); if (remaining <= 0) { param->flags |= DM_BUFFER_FULL_FLAG; break; } /* Get the status/table string from the target driver */ if (ti->type->status) { if (param->flags & DM_NOFLUSH_FLAG) status_flags |= DM_STATUS_NOFLUSH_FLAG; ti->type->status(ti, type, status_flags, outptr, remaining); } else outptr[0] = '\0'; l = strlen(outptr) + 1; if (l == remaining) { param->flags |= DM_BUFFER_FULL_FLAG; break; } outptr += l; used = param->data_start + (outptr - outbuf); outptr = align_ptr(outptr); spec->next = outptr - outbuf; } if (used) param->data_size = used; param->target_count = num_targets; } /* * Wait for a device to report an event */ static int dev_wait(struct dm_ioctl *param, size_t param_size) { int r = 0; struct mapped_device *md; struct dm_table *table; int srcu_idx; md = find_device(param); if (!md) return -ENXIO; /* * Wait for a notification event */ if (dm_wait_event(md, param->event_nr)) { r = -ERESTARTSYS; goto out; } /* * The userland program is going to want to know what * changed to trigger the event, so we may as well tell * him and save an ioctl. */ __dev_status(md, param); table = dm_get_live_or_inactive_table(md, param, &srcu_idx); if (table) retrieve_status(table, param, param_size); dm_put_live_table(md, srcu_idx); out: dm_put(md); return r; } static inline fmode_t get_mode(struct dm_ioctl *param) { fmode_t mode = FMODE_READ | FMODE_WRITE; if (param->flags & DM_READONLY_FLAG) mode = FMODE_READ; return mode; } static int next_target(struct dm_target_spec *last, uint32_t next, void *end, struct dm_target_spec **spec, char **target_params) { *spec = (struct dm_target_spec *) ((unsigned char *) last + next); *target_params = (char *) (*spec + 1); if (*spec < (last + 1)) return -EINVAL; return invalid_str(*target_params, end); } static int populate_table(struct dm_table *table, struct dm_ioctl *param, size_t param_size) { int r; unsigned int i = 0; struct dm_target_spec *spec = (struct dm_target_spec *) param; uint32_t next = param->data_start; void *end = (void *) param + param_size; char *target_params; if (!param->target_count) { DMWARN("populate_table: no targets specified"); return -EINVAL; } for (i = 0; i < param->target_count; i++) { r = next_target(spec, next, end, &spec, &target_params); if (r) { DMWARN("unable to find target"); return r; } r = dm_table_add_target(table, spec->target_type, (sector_t) spec->sector_start, (sector_t) spec->length, target_params); if (r) { DMWARN("error adding target to table"); return r; } next = spec->next; } return dm_table_complete(table); } static int table_load(struct dm_ioctl *param, size_t param_size) { int r; struct hash_cell *hc; struct dm_table *t, *old_map = NULL; struct mapped_device *md; struct target_type *immutable_target_type; md = find_device(param); if (!md) return -ENXIO; r = dm_table_create(&t, get_mode(param), param->target_count, md); if (r) goto out; r = populate_table(t, param, param_size); if (r) { dm_table_destroy(t); goto out; } immutable_target_type = dm_get_immutable_target_type(md); if (immutable_target_type && (immutable_target_type != dm_table_get_immutable_target_type(t))) { DMWARN("can't replace immutable target type %s", immutable_target_type->name); dm_table_destroy(t); r = -EINVAL; goto out; } /* Protect md->type and md->queue against concurrent table loads. */ dm_lock_md_type(md); if (dm_get_md_type(md) == DM_TYPE_NONE) /* Initial table load: acquire type of table. */ dm_set_md_type(md, dm_table_get_type(t)); else if (dm_get_md_type(md) != dm_table_get_type(t)) { DMWARN("can't change device type after initial table load."); dm_table_destroy(t); dm_unlock_md_type(md); r = -EINVAL; goto out; } /* setup md->queue to reflect md's type (may block) */ r = dm_setup_md_queue(md); if (r) { DMWARN("unable to set up device queue for new table."); dm_table_destroy(t); dm_unlock_md_type(md); goto out; } dm_unlock_md_type(md); /* stage inactive table */ down_write(&_hash_lock); hc = dm_get_mdptr(md); if (!hc || hc->md != md) { DMWARN("device has been removed from the dev hash table."); up_write(&_hash_lock); dm_table_destroy(t); r = -ENXIO; goto out; } if (hc->new_map) old_map = hc->new_map; hc->new_map = t; up_write(&_hash_lock); param->flags |= DM_INACTIVE_PRESENT_FLAG; __dev_status(md, param); out: if (old_map) { dm_sync_table(md); dm_table_destroy(old_map); } dm_put(md); return r; } static int table_clear(struct dm_ioctl *param, size_t param_size) { struct hash_cell *hc; struct mapped_device *md; struct dm_table *old_map = NULL; down_write(&_hash_lock); hc = __find_device_hash_cell(param); if (!hc) { DMDEBUG_LIMIT("device doesn't appear to be in the dev hash table."); up_write(&_hash_lock); return -ENXIO; } if (hc->new_map) { old_map = hc->new_map; hc->new_map = NULL; } param->flags &= ~DM_INACTIVE_PRESENT_FLAG; __dev_status(hc->md, param); md = hc->md; up_write(&_hash_lock); if (old_map) { dm_sync_table(md); dm_table_destroy(old_map); } dm_put(md); return 0; } /* * Retrieves a list of devices used by a particular dm device. */ static void retrieve_deps(struct dm_table *table, struct dm_ioctl *param, size_t param_size) { unsigned int count = 0; struct list_head *tmp; size_t len, needed; struct dm_dev_internal *dd; struct dm_target_deps *deps; deps = get_result_buffer(param, param_size, &len); /* * Count the devices. */ list_for_each (tmp, dm_table_get_devices(table)) count++; /* * Check we have enough space. */ needed = sizeof(*deps) + (sizeof(*deps->dev) * count); if (len < needed) { param->flags |= DM_BUFFER_FULL_FLAG; return; } /* * Fill in the devices. */ deps->count = count; count = 0; list_for_each_entry (dd, dm_table_get_devices(table), list) deps->dev[count++] = huge_encode_dev(dd->dm_dev.bdev->bd_dev); param->data_size = param->data_start + needed; } static int table_deps(struct dm_ioctl *param, size_t param_size) { struct mapped_device *md; struct dm_table *table; int srcu_idx; md = find_device(param); if (!md) return -ENXIO; __dev_status(md, param); table = dm_get_live_or_inactive_table(md, param, &srcu_idx); if (table) retrieve_deps(table, param, param_size); dm_put_live_table(md, srcu_idx); dm_put(md); return 0; } /* * Return the status of a device as a text string for each * target. */ static int table_status(struct dm_ioctl *param, size_t param_size) { struct mapped_device *md; struct dm_table *table; int srcu_idx; md = find_device(param); if (!md) return -ENXIO; __dev_status(md, param); table = dm_get_live_or_inactive_table(md, param, &srcu_idx); if (table) retrieve_status(table, param, param_size); dm_put_live_table(md, srcu_idx); dm_put(md); return 0; } static bool buffer_test_overflow(char *result, unsigned maxlen) { return !maxlen || strlen(result) + 1 >= maxlen; } /* * Process device-mapper dependent messages. * Returns a number <= 1 if message was processed by device mapper. * Returns 2 if message should be delivered to the target. */ static int message_for_md(struct mapped_device *md, unsigned argc, char **argv, char *result, unsigned maxlen) { return 2; } /* * Pass a message to the target that's at the supplied device offset. */ static int target_message(struct dm_ioctl *param, size_t param_size) { int r, argc; char **argv; struct mapped_device *md; struct dm_table *table; struct dm_target *ti; struct dm_target_msg *tmsg = (void *) param + param->data_start; size_t maxlen; char *result = get_result_buffer(param, param_size, &maxlen); int srcu_idx; md = find_device(param); if (!md) return -ENXIO; if (tmsg < (struct dm_target_msg *) param->data || invalid_str(tmsg->message, (void *) param + param_size)) { DMWARN("Invalid target message parameters."); r = -EINVAL; goto out; } r = dm_split_args(&argc, &argv, tmsg->message); if (r) { DMWARN("Failed to split target message parameters"); goto out; } if (!argc) { DMWARN("Empty message received."); goto out_argv; } r = message_for_md(md, argc, argv, result, maxlen); if (r <= 1) goto out_argv; table = dm_get_live_table(md, &srcu_idx); if (!table) goto out_table; if (dm_deleting_md(md)) { r = -ENXIO; goto out_table; } ti = dm_table_find_target(table, tmsg->sector); if (!dm_target_is_valid(ti)) { DMWARN("Target message sector outside device."); r = -EINVAL; } else if (ti->type->message) r = ti->type->message(ti, argc, argv); else { DMWARN("Target type does not support messages"); r = -EINVAL; } out_table: dm_put_live_table(md, srcu_idx); out_argv: kfree(argv); out: if (r >= 0) __dev_status(md, param); if (r == 1) { param->flags |= DM_DATA_OUT_FLAG; if (buffer_test_overflow(result, maxlen)) param->flags |= DM_BUFFER_FULL_FLAG; else param->data_size = param->data_start + strlen(result) + 1; r = 0; } dm_put(md); return r; } /* * The ioctl parameter block consists of two parts, a dm_ioctl struct * followed by a data buffer. This flag is set if the second part, * which has a variable size, is not used by the function processing * the ioctl. */ #define IOCTL_FLAGS_NO_PARAMS 1 /*----------------------------------------------------------------- * Implementation of open/close/ioctl on the special char * device. *---------------------------------------------------------------*/ static ioctl_fn lookup_ioctl(unsigned int cmd, int *ioctl_flags) { static struct { int cmd; int flags; ioctl_fn fn; } _ioctls[] = { {DM_VERSION_CMD, 0, NULL}, /* version is dealt with elsewhere */ {DM_REMOVE_ALL_CMD, IOCTL_FLAGS_NO_PARAMS, remove_all}, {DM_LIST_DEVICES_CMD, 0, list_devices}, {DM_DEV_CREATE_CMD, IOCTL_FLAGS_NO_PARAMS, dev_create}, {DM_DEV_REMOVE_CMD, IOCTL_FLAGS_NO_PARAMS, dev_remove}, {DM_DEV_RENAME_CMD, 0, dev_rename}, {DM_DEV_SUSPEND_CMD, IOCTL_FLAGS_NO_PARAMS, dev_suspend}, {DM_DEV_STATUS_CMD, IOCTL_FLAGS_NO_PARAMS, dev_status}, {DM_DEV_WAIT_CMD, 0, dev_wait}, {DM_TABLE_LOAD_CMD, 0, table_load}, {DM_TABLE_CLEAR_CMD, IOCTL_FLAGS_NO_PARAMS, table_clear}, {DM_TABLE_DEPS_CMD, 0, table_deps}, {DM_TABLE_STATUS_CMD, 0, table_status}, {DM_LIST_VERSIONS_CMD, 0, list_versions}, {DM_TARGET_MSG_CMD, 0, target_message}, {DM_DEV_SET_GEOMETRY_CMD, 0, dev_set_geometry} }; if (unlikely(cmd >= ARRAY_SIZE(_ioctls))) return NULL; *ioctl_flags = _ioctls[cmd].flags; return _ioctls[cmd].fn; } /* * As well as checking the version compatibility this always * copies the kernel interface version out. */ static int check_version(unsigned int cmd, struct dm_ioctl __user *user) { uint32_t version[3]; int r = 0; if (copy_from_user(version, user->version, sizeof(version))) return -EFAULT; if ((DM_VERSION_MAJOR != version[0]) || (DM_VERSION_MINOR < version[1])) { DMWARN("ioctl interface mismatch: " "kernel(%u.%u.%u), user(%u.%u.%u), cmd(%d)", DM_VERSION_MAJOR, DM_VERSION_MINOR, DM_VERSION_PATCHLEVEL, version[0], version[1], version[2], cmd); r = -EINVAL; } /* * Fill in the kernel version. */ version[0] = DM_VERSION_MAJOR; version[1] = DM_VERSION_MINOR; version[2] = DM_VERSION_PATCHLEVEL; if (copy_to_user(user->version, version, sizeof(version))) return -EFAULT; return r; } #define DM_PARAMS_KMALLOC 0x0001 /* Params alloced with kmalloc */ #define DM_PARAMS_VMALLOC 0x0002 /* Params alloced with vmalloc */ #define DM_WIPE_BUFFER 0x0010 /* Wipe input buffer before returning from ioctl */ static void free_params(struct dm_ioctl *param, size_t param_size, int param_flags) { if (param_flags & DM_WIPE_BUFFER) memset(param, 0, param_size); if (param_flags & DM_PARAMS_KMALLOC) kfree(param); if (param_flags & DM_PARAMS_VMALLOC) vfree(param); } static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl *param_kernel, int ioctl_flags, struct dm_ioctl **param, int *param_flags) { struct dm_ioctl *dmi; int secure_data; const size_t minimum_data_size = sizeof(*param_kernel) - sizeof(param_kernel->data); if (copy_from_user(param_kernel, user, minimum_data_size)) return -EFAULT; if (param_kernel->data_size < minimum_data_size) return -EINVAL; secure_data = param_kernel->flags & DM_SECURE_DATA_FLAG; *param_flags = secure_data ? DM_WIPE_BUFFER : 0; if (ioctl_flags & IOCTL_FLAGS_NO_PARAMS) { dmi = param_kernel; dmi->data_size = minimum_data_size; goto data_copied; } /* * Try to avoid low memory issues when a device is suspended. * Use kmalloc() rather than vmalloc() when we can. */ dmi = NULL; if (param_kernel->data_size <= KMALLOC_MAX_SIZE) { dmi = kmalloc(param_kernel->data_size, GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN); if (dmi) *param_flags |= DM_PARAMS_KMALLOC; } if (!dmi) { unsigned noio_flag; noio_flag = memalloc_noio_save(); dmi = __vmalloc(param_kernel->data_size, GFP_NOIO | __GFP_REPEAT | __GFP_HIGH | __GFP_HIGHMEM, PAGE_KERNEL); memalloc_noio_restore(noio_flag); if (dmi) *param_flags |= DM_PARAMS_VMALLOC; } if (!dmi) { if (secure_data && clear_user(user, param_kernel->data_size)) return -EFAULT; return -ENOMEM; } if (copy_from_user(dmi, user, param_kernel->data_size)) goto bad; data_copied: /* * Abort if something changed the ioctl data while it was being copied. */ if (dmi->data_size != param_kernel->data_size) { DMERR("rejecting ioctl: data size modified while processing parameters"); goto bad; } /* Wipe the user buffer so we do not return it to userspace */ if (secure_data && clear_user(user, param_kernel->data_size)) goto bad; *param = dmi; return 0; bad: free_params(dmi, param_kernel->data_size, *param_flags); return -EFAULT; } static int validate_params(uint cmd, struct dm_ioctl *param) { /* Always clear this flag */ param->flags &= ~DM_BUFFER_FULL_FLAG; param->flags &= ~DM_UEVENT_GENERATED_FLAG; param->flags &= ~DM_SECURE_DATA_FLAG; param->flags &= ~DM_DATA_OUT_FLAG; /* Ignores parameters */ if (cmd == DM_REMOVE_ALL_CMD || cmd == DM_LIST_DEVICES_CMD || cmd == DM_LIST_VERSIONS_CMD) return 0; if ((cmd == DM_DEV_CREATE_CMD)) { if (!*param->name) { DMWARN("name not supplied when creating device"); return -EINVAL; } } else if ((*param->uuid && *param->name)) { DMWARN("only supply one of name or uuid, cmd(%u)", cmd); return -EINVAL; } /* Ensure strings are terminated */ param->name[DM_NAME_LEN - 1] = '\0'; param->uuid[DM_UUID_LEN - 1] = '\0'; return 0; } static int ctl_ioctl(uint command, struct dm_ioctl __user *user) { int r = 0; int ioctl_flags; int param_flags; unsigned int cmd; struct dm_ioctl *uninitialized_var(param); ioctl_fn fn = NULL; size_t input_param_size; struct dm_ioctl param_kernel; /* only root can play with this */ if (!capable(CAP_SYS_ADMIN)) return -EACCES; if (_IOC_TYPE(command) != DM_IOCTL) return -ENOTTY; cmd = _IOC_NR(command); /* * Check the interface version passed in. This also * writes out the kernel's interface version. */ r = check_version(cmd, user); if (r) return r; /* * Nothing more to do for the version command. */ if (cmd == DM_VERSION_CMD) return 0; fn = lookup_ioctl(cmd, &ioctl_flags); if (!fn) { DMWARN("dm_ctl_ioctl: unknown command 0x%x", command); return -ENOTTY; } /* * Copy the parameters into kernel space. */ r = copy_params(user, ¶m_kernel, ioctl_flags, ¶m, ¶m_flags); if (r) return r; input_param_size = param->data_size; r = validate_params(cmd, param); if (r) goto out; param->data_size = sizeof(*param); r = fn(param, input_param_size); if (unlikely(param->flags & DM_BUFFER_FULL_FLAG) && unlikely(ioctl_flags & IOCTL_FLAGS_NO_PARAMS)) DMERR("ioctl %d tried to output some data but has IOCTL_FLAGS_NO_PARAMS set", cmd); /* * Copy the results back to userland. */ if (!r && copy_to_user(user, param, param->data_size)) r = -EFAULT; out: free_params(param, input_param_size, param_flags); return r; } static long dm_ctl_ioctl(struct file *file, uint command, ulong u) { return (long)ctl_ioctl(command, (struct dm_ioctl __user *)u); } #ifdef CONFIG_COMPAT static long dm_compat_ctl_ioctl(struct file *file, uint command, ulong u) { return (long)dm_ctl_ioctl(file, command, (ulong) compat_ptr(u)); } #else #define dm_compat_ctl_ioctl NULL #endif static const struct file_operations _ctl_fops = { .open = nonseekable_open, .unlocked_ioctl = dm_ctl_ioctl, .compat_ioctl = dm_compat_ctl_ioctl, .owner = THIS_MODULE, .llseek = noop_llseek, }; static struct miscdevice _dm_misc = { .minor = MAPPER_CTRL_MINOR, .name = DM_NAME, .nodename = DM_DIR "/" DM_CONTROL_NODE, .fops = &_ctl_fops }; MODULE_ALIAS_MISCDEV(MAPPER_CTRL_MINOR); MODULE_ALIAS("devname:" DM_DIR "/" DM_CONTROL_NODE); /* * Create misc character device and link to DM_DIR/control. */ int __init dm_interface_init(void) { int r; r = dm_hash_init(); if (r) return r; r = misc_register(&_dm_misc); if (r) { DMERR("misc_register failed for control device"); dm_hash_exit(); return r; } DMINFO("%d.%d.%d%s initialised: %s", DM_VERSION_MAJOR, DM_VERSION_MINOR, DM_VERSION_PATCHLEVEL, DM_VERSION_EXTRA, DM_DRIVER_EMAIL); return 0; } void dm_interface_exit(void) { if (misc_deregister(&_dm_misc) < 0) DMERR("misc_deregister failed for control device"); dm_hash_exit(); } /** * dm_copy_name_and_uuid - Copy mapped device name & uuid into supplied buffers * @md: Pointer to mapped_device * @name: Buffer (size DM_NAME_LEN) for name * @uuid: Buffer (size DM_UUID_LEN) for uuid or empty string if uuid not defined */ int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid) { int r = 0; struct hash_cell *hc; if (!md) return -ENXIO; mutex_lock(&dm_hash_cells_mutex); hc = dm_get_mdptr(md); if (!hc || hc->md != md) { r = -ENXIO; goto out; } if (name) strcpy(name, hc->name); if (uuid) strcpy(uuid, hc->uuid ? : ""); out: mutex_unlock(&dm_hash_cells_mutex); return r; }