/* * Copyright (C) 2001, 2002 Sistina Software (UK) Limited. * Copyright (C) 2004 - 2005 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 #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; }; 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(void); /* * Guards access to both hash tables. */ static DECLARE_RWSEM(_hash_lock); 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); devfs_mk_dir(DM_DIR); return 0; } static void dm_hash_exit(void) { dm_hash_remove_all(); devfs_remove(DM_DIR); } /*----------------------------------------------------------------- * 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)) 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)) return hc; return NULL; } /*----------------------------------------------------------------- * 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); } } /* * devfs stuff. */ static int register_with_devfs(struct hash_cell *hc) { struct gendisk *disk = dm_disk(hc->md); devfs_mk_bdev(MKDEV(disk->major, disk->first_minor), S_IFBLK | S_IRUSR | S_IWUSR | S_IRGRP, DM_DIR "/%s", hc->name); return 0; } static int unregister_with_devfs(struct hash_cell *hc) { devfs_remove(DM_DIR"/%s", hc->name); return 0; } /* * 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; /* * 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); if (__get_name_cell(name)) goto bad; list_add(&cell->name_list, _name_buckets + hash_str(name)); if (uuid) { if (__get_uuid_cell(uuid)) { list_del(&cell->name_list); goto bad; } list_add(&cell->uuid_list, _uuid_buckets + hash_str(uuid)); } register_with_devfs(cell); dm_get(md); dm_set_mdptr(md, cell); up_write(&_hash_lock); return 0; bad: up_write(&_hash_lock); free_cell(cell); return -EBUSY; } static void __hash_remove(struct hash_cell *hc) { /* remove from the dev hash */ list_del(&hc->uuid_list); list_del(&hc->name_list); unregister_with_devfs(hc); dm_set_mdptr(hc->md, NULL); dm_put(hc->md); if (hc->new_map) dm_table_put(hc->new_map); free_cell(hc); } static void dm_hash_remove_all(void) { int i; struct hash_cell *hc; struct list_head *tmp, *n; down_write(&_hash_lock); for (i = 0; i < NUM_BUCKETS; i++) { list_for_each_safe (tmp, n, _name_buckets + i) { hc = list_entry(tmp, struct hash_cell, name_list); __hash_remove(hc); } } up_write(&_hash_lock); } static int dm_hash_rename(const char *old, const char *new) { char *new_name, *old_name; struct hash_cell *hc; /* * duplicate new. */ new_name = kstrdup(new, GFP_KERNEL); if (!new_name) return -ENOMEM; down_write(&_hash_lock); /* * Is new free ? */ hc = __get_name_cell(new); if (hc) { DMWARN("asked to rename to an already existing name %s -> %s", old, new); up_write(&_hash_lock); kfree(new_name); return -EBUSY; } /* * Is there such a device as 'old' ? */ hc = __get_name_cell(old); if (!hc) { DMWARN("asked to rename a non existent device %s -> %s", old, new); up_write(&_hash_lock); kfree(new_name); return -ENXIO; } /* * rename and move the name cell. */ unregister_with_devfs(hc); list_del(&hc->name_list); old_name = hc->name; hc->name = new_name; list_add(&hc->name_list, _name_buckets + hash_str(new_name)); /* rename the device node in devfs */ register_with_devfs(hc); up_write(&_hash_lock); kfree(old_name); return 0; } /*----------------------------------------------------------------- * 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(); 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(MKDEV(disk->major, disk->first_minor)); 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 += strlen(tt->name); *needed += sizeof(tt->version); *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; } /* * Fills in a dm_ioctl structure, ready for sending back to * userland. */ static int __dev_status(struct mapped_device *md, struct dm_ioctl *param) { struct gendisk *disk = dm_disk(md); struct dm_table *table; struct block_device *bdev; param->flags &= ~(DM_SUSPEND_FLAG | DM_READONLY_FLAG | DM_ACTIVE_PRESENT_FLAG); if (dm_suspended(md)) param->flags |= DM_SUSPEND_FLAG; param->dev = huge_encode_dev(MKDEV(disk->major, disk->first_minor)); if (!(param->flags & DM_SKIP_BDGET_FLAG)) { bdev = bdget_disk(disk, 0); if (!bdev) return -ENXIO; /* * 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 = bdev->bd_openers; bdput(bdev); } else param->open_count = -1; if (disk->policy) param->flags |= DM_READONLY_FLAG; param->event_nr = dm_get_event_nr(md); table = dm_get_table(md); if (table) { param->flags |= DM_ACTIVE_PRESENT_FLAG; param->target_count = dm_table_get_num_targets(table); dm_table_put(table); } else param->target_count = 0; return 0; } static int dev_create(struct dm_ioctl *param, size_t param_size) { int r; struct mapped_device *md; r = check_name(param->name); if (r) return r; if (param->flags & DM_PERSISTENT_DEV_FLAG) r = dm_create_with_minor(MINOR(huge_decode_dev(param->dev)), &md); else r = dm_create(&md); if (r) return r; r = dm_hash_insert(param->name, *param->uuid ? param->uuid : NULL, md); if (r) { dm_put(md); return r; } param->flags &= ~DM_INACTIVE_PRESENT_FLAG; r = __dev_status(md, param); dm_put(md); return r; } /* * Always use UUID for lookups if it's present, otherwise use name or dev. */ static inline struct hash_cell *__find_device_hash_cell(struct dm_ioctl *param) { if (*param->uuid) return __get_uuid_cell(param->uuid); else if (*param->name) return __get_name_cell(param->name); else return dm_get_mdptr(huge_decode_dev(param->dev)); } static inline 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; dm_get(md); /* * Sneakily write in both the name and the uuid * while we have the cell. */ strncpy(param->name, hc->name, sizeof(param->name)); if (hc->uuid) strncpy(param->uuid, hc->uuid, sizeof(param->uuid)-1); else param->uuid[0] = '\0'; if (hc->new_map) param->flags |= DM_INACTIVE_PRESENT_FLAG; else param->flags &= ~DM_INACTIVE_PRESENT_FLAG; } up_read(&_hash_lock); return md; } static int dev_remove(struct dm_ioctl *param, size_t param_size) { struct hash_cell *hc; down_write(&_hash_lock); hc = __find_device_hash_cell(param); if (!hc) { DMWARN("device doesn't appear to be in the dev hash table."); up_write(&_hash_lock); return -ENXIO; } __hash_remove(hc); up_write(&_hash_lock); param->data_size = 0; 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_name = (char *) param + param->data_start; if (new_name < (char *) (param + 1) || invalid_str(new_name, (void *) param + param_size)) { DMWARN("Invalid new logical volume name supplied."); return -EINVAL; } r = check_name(new_name); if (r) return r; param->data_size = 0; return dm_hash_rename(param->name, new_name); } static int do_suspend(struct dm_ioctl *param) { int r = 0; struct mapped_device *md; md = find_device(param); if (!md) return -ENXIO; if (!dm_suspended(md)) r = dm_suspend(md); if (!r) r = __dev_status(md, param); dm_put(md); return r; } static int do_resume(struct dm_ioctl *param) { int r = 0; struct hash_cell *hc; struct mapped_device *md; struct dm_table *new_map; down_write(&_hash_lock); hc = __find_device_hash_cell(param); if (!hc) { DMWARN("device doesn't appear to be in the dev hash table."); up_write(&_hash_lock); return -ENXIO; } md = hc->md; dm_get(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 (!dm_suspended(md)) dm_suspend(md); r = dm_swap_table(md, new_map); if (r) { dm_put(md); dm_table_put(new_map); return r; } if (dm_table_get_mode(new_map) & FMODE_WRITE) set_disk_ro(dm_disk(md), 0); else set_disk_ro(dm_disk(md), 1); dm_table_put(new_map); } if (dm_suspended(md)) r = dm_resume(md); if (!r) 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) { int r; struct mapped_device *md; md = find_device(param); if (!md) return -ENXIO; r = __dev_status(md, param); dm_put(md); return r; } /* * 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; 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); 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 (ti->type->status(ti, type, outptr, remaining)) { param->flags |= DM_BUFFER_FULL_FLAG; break; } } else outptr[0] = '\0'; outptr += strlen(outptr) + 1; 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; struct mapped_device *md; struct dm_table *table; 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. */ r = __dev_status(md, param); if (r) goto out; table = dm_get_table(md); if (table) { retrieve_status(table, param, param_size); dm_table_put(table); } out: dm_put(md); return r; } static inline int get_mode(struct dm_ioctl *param) { int 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; r = dm_table_create(&t, get_mode(param), param->target_count); if (r) return r; r = populate_table(t, param, param_size); if (r) { dm_table_put(t); return r; } down_write(&_hash_lock); hc = __find_device_hash_cell(param); if (!hc) { DMWARN("device doesn't appear to be in the dev hash table."); up_write(&_hash_lock); return -ENXIO; } if (hc->new_map) dm_table_put(hc->new_map); hc->new_map = t; param->flags |= DM_INACTIVE_PRESENT_FLAG; r = __dev_status(hc->md, param); up_write(&_hash_lock); return r; } static int table_clear(struct dm_ioctl *param, size_t param_size) { int r; struct hash_cell *hc; down_write(&_hash_lock); hc = __find_device_hash_cell(param); if (!hc) { DMWARN("device doesn't appear to be in the dev hash table."); up_write(&_hash_lock); return -ENXIO; } if (hc->new_map) { dm_table_put(hc->new_map); hc->new_map = NULL; } param->flags &= ~DM_INACTIVE_PRESENT_FLAG; r = __dev_status(hc->md, param); up_write(&_hash_lock); return r; } /* * 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 *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->bdev->bd_dev); param->data_size = param->data_start + needed; } static int table_deps(struct dm_ioctl *param, size_t param_size) { int r = 0; struct mapped_device *md; struct dm_table *table; md = find_device(param); if (!md) return -ENXIO; r = __dev_status(md, param); if (r) goto out; table = dm_get_table(md); if (table) { retrieve_deps(table, param, param_size); dm_table_put(table); } out: dm_put(md); return r; } /* * 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) { int r; struct mapped_device *md; struct dm_table *table; md = find_device(param); if (!md) return -ENXIO; r = __dev_status(md, param); if (r) goto out; table = dm_get_table(md); if (table) { retrieve_status(table, param, param_size); dm_table_put(table); } out: dm_put(md); return r; } /* * 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; md = find_device(param); if (!md) return -ENXIO; r = __dev_status(md, param); if (r) goto out; if (tmsg < (struct dm_target_msg *) (param + 1) || 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; } table = dm_get_table(md); if (!table) goto out_argv; if (tmsg->sector >= dm_table_get_size(table)) { DMWARN("Target message sector outside device."); r = -EINVAL; goto out_table; } ti = dm_table_find_target(table, tmsg->sector); if (ti->type->message) r = ti->type->message(ti, argc, argv); else { DMWARN("Target type does not support messages"); r = -EINVAL; } out_table: dm_table_put(table); out_argv: kfree(argv); out: param->data_size = 0; dm_put(md); return r; } /*----------------------------------------------------------------- * Implementation of open/close/ioctl on the special char * device. *---------------------------------------------------------------*/ static ioctl_fn lookup_ioctl(unsigned int cmd) { static struct { int cmd; ioctl_fn fn; } _ioctls[] = { {DM_VERSION_CMD, NULL}, /* version is dealt with elsewhere */ {DM_REMOVE_ALL_CMD, remove_all}, {DM_LIST_DEVICES_CMD, list_devices}, {DM_DEV_CREATE_CMD, dev_create}, {DM_DEV_REMOVE_CMD, dev_remove}, {DM_DEV_RENAME_CMD, dev_rename}, {DM_DEV_SUSPEND_CMD, dev_suspend}, {DM_DEV_STATUS_CMD, dev_status}, {DM_DEV_WAIT_CMD, dev_wait}, {DM_TABLE_LOAD_CMD, table_load}, {DM_TABLE_CLEAR_CMD, table_clear}, {DM_TABLE_DEPS_CMD, table_deps}, {DM_TABLE_STATUS_CMD, table_status}, {DM_LIST_VERSIONS_CMD, list_versions}, {DM_TARGET_MSG_CMD, target_message} }; return (cmd >= ARRAY_SIZE(_ioctls)) ? NULL : _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; } static void free_params(struct dm_ioctl *param) { vfree(param); } static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl **param) { struct dm_ioctl tmp, *dmi; if (copy_from_user(&tmp, user, sizeof(tmp))) return -EFAULT; if (tmp.data_size < sizeof(tmp)) return -EINVAL; dmi = (struct dm_ioctl *) vmalloc(tmp.data_size); if (!dmi) return -ENOMEM; if (copy_from_user(dmi, user, tmp.data_size)) { vfree(dmi); return -EFAULT; } *param = dmi; return 0; } static int validate_params(uint cmd, struct dm_ioctl *param) { /* Always clear this flag */ param->flags &= ~DM_BUFFER_FULL_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(struct inode *inode, struct file *file, uint command, ulong u) { int r = 0; unsigned int cmd; struct dm_ioctl *param; struct dm_ioctl __user *user = (struct dm_ioctl __user *) u; ioctl_fn fn = NULL; size_t param_size; /* 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); if (!fn) { DMWARN("dm_ctl_ioctl: unknown command 0x%x", command); return -ENOTTY; } /* * Trying to avoid low memory issues when a device is * suspended. */ current->flags |= PF_MEMALLOC; /* * Copy the parameters into kernel space. */ r = copy_params(user, ¶m); if (r) { current->flags &= ~PF_MEMALLOC; return r; } /* * FIXME: eventually we will remove the PF_MEMALLOC flag * here. However the tools still do nasty things like * 'load' while a device is suspended. */ r = validate_params(cmd, param); if (r) goto out; param_size = param->data_size; param->data_size = sizeof(*param); r = fn(param, param_size); /* * Copy the results back to userland. */ if (!r && copy_to_user(user, param, param->data_size)) r = -EFAULT; out: free_params(param); current->flags &= ~PF_MEMALLOC; return r; } static struct file_operations _ctl_fops = { .ioctl = ctl_ioctl, .owner = THIS_MODULE, }; static struct miscdevice _dm_misc = { .minor = MISC_DYNAMIC_MINOR, .name = DM_NAME, .devfs_name = "mapper/control", .fops = &_ctl_fops }; /* * 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(); }