Root/drivers/md/dm-ioctl.c

1/*
2 * Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
3 * Copyright (C) 2004 - 2006 Red Hat, Inc. All rights reserved.
4 *
5 * This file is released under the GPL.
6 */
7
8#include "dm.h"
9
10#include <linux/module.h>
11#include <linux/vmalloc.h>
12#include <linux/miscdevice.h>
13#include <linux/init.h>
14#include <linux/wait.h>
15#include <linux/slab.h>
16#include <linux/dm-ioctl.h>
17#include <linux/hdreg.h>
18#include <linux/compat.h>
19
20#include <asm/uaccess.h>
21
22#define DM_MSG_PREFIX "ioctl"
23#define DM_DRIVER_EMAIL "dm-devel@redhat.com"
24
25/*-----------------------------------------------------------------
26 * The ioctl interface needs to be able to look up devices by
27 * name or uuid.
28 *---------------------------------------------------------------*/
29struct hash_cell {
30    struct list_head name_list;
31    struct list_head uuid_list;
32
33    char *name;
34    char *uuid;
35    struct mapped_device *md;
36    struct dm_table *new_map;
37};
38
39struct vers_iter {
40    size_t param_size;
41    struct dm_target_versions *vers, *old_vers;
42    char *end;
43    uint32_t flags;
44};
45
46
47#define NUM_BUCKETS 64
48#define MASK_BUCKETS (NUM_BUCKETS - 1)
49static struct list_head _name_buckets[NUM_BUCKETS];
50static struct list_head _uuid_buckets[NUM_BUCKETS];
51
52static void dm_hash_remove_all(int keep_open_devices);
53
54/*
55 * Guards access to both hash tables.
56 */
57static DECLARE_RWSEM(_hash_lock);
58
59/*
60 * Protects use of mdptr to obtain hash cell name and uuid from mapped device.
61 */
62static DEFINE_MUTEX(dm_hash_cells_mutex);
63
64static void init_buckets(struct list_head *buckets)
65{
66    unsigned int i;
67
68    for (i = 0; i < NUM_BUCKETS; i++)
69        INIT_LIST_HEAD(buckets + i);
70}
71
72static int dm_hash_init(void)
73{
74    init_buckets(_name_buckets);
75    init_buckets(_uuid_buckets);
76    return 0;
77}
78
79static void dm_hash_exit(void)
80{
81    dm_hash_remove_all(0);
82}
83
84/*-----------------------------------------------------------------
85 * Hash function:
86 * We're not really concerned with the str hash function being
87 * fast since it's only used by the ioctl interface.
88 *---------------------------------------------------------------*/
89static unsigned int hash_str(const char *str)
90{
91    const unsigned int hash_mult = 2654435387U;
92    unsigned int h = 0;
93
94    while (*str)
95        h = (h + (unsigned int) *str++) * hash_mult;
96
97    return h & MASK_BUCKETS;
98}
99
100/*-----------------------------------------------------------------
101 * Code for looking up a device by name
102 *---------------------------------------------------------------*/
103static struct hash_cell *__get_name_cell(const char *str)
104{
105    struct hash_cell *hc;
106    unsigned int h = hash_str(str);
107
108    list_for_each_entry (hc, _name_buckets + h, name_list)
109        if (!strcmp(hc->name, str)) {
110            dm_get(hc->md);
111            return hc;
112        }
113
114    return NULL;
115}
116
117static struct hash_cell *__get_uuid_cell(const char *str)
118{
119    struct hash_cell *hc;
120    unsigned int h = hash_str(str);
121
122    list_for_each_entry (hc, _uuid_buckets + h, uuid_list)
123        if (!strcmp(hc->uuid, str)) {
124            dm_get(hc->md);
125            return hc;
126        }
127
128    return NULL;
129}
130
131static struct hash_cell *__get_dev_cell(uint64_t dev)
132{
133    struct mapped_device *md;
134    struct hash_cell *hc;
135
136    md = dm_get_md(huge_decode_dev(dev));
137    if (!md)
138        return NULL;
139
140    hc = dm_get_mdptr(md);
141    if (!hc) {
142        dm_put(md);
143        return NULL;
144    }
145
146    return hc;
147}
148
149/*-----------------------------------------------------------------
150 * Inserting, removing and renaming a device.
151 *---------------------------------------------------------------*/
152static struct hash_cell *alloc_cell(const char *name, const char *uuid,
153                    struct mapped_device *md)
154{
155    struct hash_cell *hc;
156
157    hc = kmalloc(sizeof(*hc), GFP_KERNEL);
158    if (!hc)
159        return NULL;
160
161    hc->name = kstrdup(name, GFP_KERNEL);
162    if (!hc->name) {
163        kfree(hc);
164        return NULL;
165    }
166
167    if (!uuid)
168        hc->uuid = NULL;
169
170    else {
171        hc->uuid = kstrdup(uuid, GFP_KERNEL);
172        if (!hc->uuid) {
173            kfree(hc->name);
174            kfree(hc);
175            return NULL;
176        }
177    }
178
179    INIT_LIST_HEAD(&hc->name_list);
180    INIT_LIST_HEAD(&hc->uuid_list);
181    hc->md = md;
182    hc->new_map = NULL;
183    return hc;
184}
185
186static void free_cell(struct hash_cell *hc)
187{
188    if (hc) {
189        kfree(hc->name);
190        kfree(hc->uuid);
191        kfree(hc);
192    }
193}
194
195/*
196 * The kdev_t and uuid of a device can never change once it is
197 * initially inserted.
198 */
199static int dm_hash_insert(const char *name, const char *uuid, struct mapped_device *md)
200{
201    struct hash_cell *cell, *hc;
202
203    /*
204     * Allocate the new cells.
205     */
206    cell = alloc_cell(name, uuid, md);
207    if (!cell)
208        return -ENOMEM;
209
210    /*
211     * Insert the cell into both hash tables.
212     */
213    down_write(&_hash_lock);
214    hc = __get_name_cell(name);
215    if (hc) {
216        dm_put(hc->md);
217        goto bad;
218    }
219
220    list_add(&cell->name_list, _name_buckets + hash_str(name));
221
222    if (uuid) {
223        hc = __get_uuid_cell(uuid);
224        if (hc) {
225            list_del(&cell->name_list);
226            dm_put(hc->md);
227            goto bad;
228        }
229        list_add(&cell->uuid_list, _uuid_buckets + hash_str(uuid));
230    }
231    dm_get(md);
232    mutex_lock(&dm_hash_cells_mutex);
233    dm_set_mdptr(md, cell);
234    mutex_unlock(&dm_hash_cells_mutex);
235    up_write(&_hash_lock);
236
237    return 0;
238
239 bad:
240    up_write(&_hash_lock);
241    free_cell(cell);
242    return -EBUSY;
243}
244
245static void __hash_remove(struct hash_cell *hc)
246{
247    struct dm_table *table;
248
249    /* remove from the dev hash */
250    list_del(&hc->uuid_list);
251    list_del(&hc->name_list);
252    mutex_lock(&dm_hash_cells_mutex);
253    dm_set_mdptr(hc->md, NULL);
254    mutex_unlock(&dm_hash_cells_mutex);
255
256    table = dm_get_live_table(hc->md);
257    if (table) {
258        dm_table_event(table);
259        dm_table_put(table);
260    }
261
262    if (hc->new_map)
263        dm_table_destroy(hc->new_map);
264    dm_put(hc->md);
265    free_cell(hc);
266}
267
268static void dm_hash_remove_all(int keep_open_devices)
269{
270    int i, dev_skipped;
271    struct hash_cell *hc;
272    struct mapped_device *md;
273
274retry:
275    dev_skipped = 0;
276
277    down_write(&_hash_lock);
278
279    for (i = 0; i < NUM_BUCKETS; i++) {
280        list_for_each_entry(hc, _name_buckets + i, name_list) {
281            md = hc->md;
282            dm_get(md);
283
284            if (keep_open_devices && dm_lock_for_deletion(md)) {
285                dm_put(md);
286                dev_skipped++;
287                continue;
288            }
289
290            __hash_remove(hc);
291
292            up_write(&_hash_lock);
293
294            dm_put(md);
295            if (likely(keep_open_devices))
296                dm_destroy(md);
297            else
298                dm_destroy_immediate(md);
299
300            /*
301             * Some mapped devices may be using other mapped
302             * devices, so repeat until we make no further
303             * progress. If a new mapped device is created
304             * here it will also get removed.
305             */
306            goto retry;
307        }
308    }
309
310    up_write(&_hash_lock);
311
312    if (dev_skipped)
313        DMWARN("remove_all left %d open device(s)", dev_skipped);
314}
315
316/*
317 * Set the uuid of a hash_cell that isn't already set.
318 */
319static void __set_cell_uuid(struct hash_cell *hc, char *new_uuid)
320{
321    mutex_lock(&dm_hash_cells_mutex);
322    hc->uuid = new_uuid;
323    mutex_unlock(&dm_hash_cells_mutex);
324
325    list_add(&hc->uuid_list, _uuid_buckets + hash_str(new_uuid));
326}
327
328/*
329 * Changes the name of a hash_cell and returns the old name for
330 * the caller to free.
331 */
332static char *__change_cell_name(struct hash_cell *hc, char *new_name)
333{
334    char *old_name;
335
336    /*
337     * Rename and move the name cell.
338     */
339    list_del(&hc->name_list);
340    old_name = hc->name;
341
342    mutex_lock(&dm_hash_cells_mutex);
343    hc->name = new_name;
344    mutex_unlock(&dm_hash_cells_mutex);
345
346    list_add(&hc->name_list, _name_buckets + hash_str(new_name));
347
348    return old_name;
349}
350
351static struct mapped_device *dm_hash_rename(struct dm_ioctl *param,
352                        const char *new)
353{
354    char *new_data, *old_name = NULL;
355    struct hash_cell *hc;
356    struct dm_table *table;
357    struct mapped_device *md;
358    unsigned change_uuid = (param->flags & DM_UUID_FLAG) ? 1 : 0;
359
360    /*
361     * duplicate new.
362     */
363    new_data = kstrdup(new, GFP_KERNEL);
364    if (!new_data)
365        return ERR_PTR(-ENOMEM);
366
367    down_write(&_hash_lock);
368
369    /*
370     * Is new free ?
371     */
372    if (change_uuid)
373        hc = __get_uuid_cell(new);
374    else
375        hc = __get_name_cell(new);
376
377    if (hc) {
378        DMWARN("Unable to change %s on mapped device %s to one that "
379               "already exists: %s",
380               change_uuid ? "uuid" : "name",
381               param->name, new);
382        dm_put(hc->md);
383        up_write(&_hash_lock);
384        kfree(new_data);
385        return ERR_PTR(-EBUSY);
386    }
387
388    /*
389     * Is there such a device as 'old' ?
390     */
391    hc = __get_name_cell(param->name);
392    if (!hc) {
393        DMWARN("Unable to rename non-existent device, %s to %s%s",
394               param->name, change_uuid ? "uuid " : "", new);
395        up_write(&_hash_lock);
396        kfree(new_data);
397        return ERR_PTR(-ENXIO);
398    }
399
400    /*
401     * Does this device already have a uuid?
402     */
403    if (change_uuid && hc->uuid) {
404        DMWARN("Unable to change uuid of mapped device %s to %s "
405               "because uuid is already set to %s",
406               param->name, new, hc->uuid);
407        dm_put(hc->md);
408        up_write(&_hash_lock);
409        kfree(new_data);
410        return ERR_PTR(-EINVAL);
411    }
412
413    if (change_uuid)
414        __set_cell_uuid(hc, new_data);
415    else
416        old_name = __change_cell_name(hc, new_data);
417
418    /*
419     * Wake up any dm event waiters.
420     */
421    table = dm_get_live_table(hc->md);
422    if (table) {
423        dm_table_event(table);
424        dm_table_put(table);
425    }
426
427    if (!dm_kobject_uevent(hc->md, KOBJ_CHANGE, param->event_nr))
428        param->flags |= DM_UEVENT_GENERATED_FLAG;
429
430    md = hc->md;
431    up_write(&_hash_lock);
432    kfree(old_name);
433
434    return md;
435}
436
437/*-----------------------------------------------------------------
438 * Implementation of the ioctl commands
439 *---------------------------------------------------------------*/
440/*
441 * All the ioctl commands get dispatched to functions with this
442 * prototype.
443 */
444typedef int (*ioctl_fn)(struct dm_ioctl *param, size_t param_size);
445
446static int remove_all(struct dm_ioctl *param, size_t param_size)
447{
448    dm_hash_remove_all(1);
449    param->data_size = 0;
450    return 0;
451}
452
453/*
454 * Round up the ptr to an 8-byte boundary.
455 */
456#define ALIGN_MASK 7
457static inline void *align_ptr(void *ptr)
458{
459    return (void *) (((size_t) (ptr + ALIGN_MASK)) & ~ALIGN_MASK);
460}
461
462/*
463 * Retrieves the data payload buffer from an already allocated
464 * struct dm_ioctl.
465 */
466static void *get_result_buffer(struct dm_ioctl *param, size_t param_size,
467                   size_t *len)
468{
469    param->data_start = align_ptr(param + 1) - (void *) param;
470
471    if (param->data_start < param_size)
472        *len = param_size - param->data_start;
473    else
474        *len = 0;
475
476    return ((void *) param) + param->data_start;
477}
478
479static int list_devices(struct dm_ioctl *param, size_t param_size)
480{
481    unsigned int i;
482    struct hash_cell *hc;
483    size_t len, needed = 0;
484    struct gendisk *disk;
485    struct dm_name_list *nl, *old_nl = NULL;
486
487    down_write(&_hash_lock);
488
489    /*
490     * Loop through all the devices working out how much
491     * space we need.
492     */
493    for (i = 0; i < NUM_BUCKETS; i++) {
494        list_for_each_entry (hc, _name_buckets + i, name_list) {
495            needed += sizeof(struct dm_name_list);
496            needed += strlen(hc->name) + 1;
497            needed += ALIGN_MASK;
498        }
499    }
500
501    /*
502     * Grab our output buffer.
503     */
504    nl = get_result_buffer(param, param_size, &len);
505    if (len < needed) {
506        param->flags |= DM_BUFFER_FULL_FLAG;
507        goto out;
508    }
509    param->data_size = param->data_start + needed;
510
511    nl->dev = 0; /* Flags no data */
512
513    /*
514     * Now loop through filling out the names.
515     */
516    for (i = 0; i < NUM_BUCKETS; i++) {
517        list_for_each_entry (hc, _name_buckets + i, name_list) {
518            if (old_nl)
519                old_nl->next = (uint32_t) ((void *) nl -
520                               (void *) old_nl);
521            disk = dm_disk(hc->md);
522            nl->dev = huge_encode_dev(disk_devt(disk));
523            nl->next = 0;
524            strcpy(nl->name, hc->name);
525
526            old_nl = nl;
527            nl = align_ptr(((void *) ++nl) + strlen(hc->name) + 1);
528        }
529    }
530
531 out:
532    up_write(&_hash_lock);
533    return 0;
534}
535
536static void list_version_get_needed(struct target_type *tt, void *needed_param)
537{
538    size_t *needed = needed_param;
539
540    *needed += sizeof(struct dm_target_versions);
541    *needed += strlen(tt->name);
542    *needed += ALIGN_MASK;
543}
544
545static void list_version_get_info(struct target_type *tt, void *param)
546{
547    struct vers_iter *info = param;
548
549    /* Check space - it might have changed since the first iteration */
550    if ((char *)info->vers + sizeof(tt->version) + strlen(tt->name) + 1 >
551    info->end) {
552
553    info->flags = DM_BUFFER_FULL_FLAG;
554    return;
555    }
556
557    if (info->old_vers)
558    info->old_vers->next = (uint32_t) ((void *)info->vers -
559                       (void *)info->old_vers);
560    info->vers->version[0] = tt->version[0];
561    info->vers->version[1] = tt->version[1];
562    info->vers->version[2] = tt->version[2];
563    info->vers->next = 0;
564    strcpy(info->vers->name, tt->name);
565
566    info->old_vers = info->vers;
567    info->vers = align_ptr(((void *) ++info->vers) + strlen(tt->name) + 1);
568}
569
570static int list_versions(struct dm_ioctl *param, size_t param_size)
571{
572    size_t len, needed = 0;
573    struct dm_target_versions *vers;
574    struct vers_iter iter_info;
575
576    /*
577     * Loop through all the devices working out how much
578     * space we need.
579     */
580    dm_target_iterate(list_version_get_needed, &needed);
581
582    /*
583     * Grab our output buffer.
584     */
585    vers = get_result_buffer(param, param_size, &len);
586    if (len < needed) {
587        param->flags |= DM_BUFFER_FULL_FLAG;
588        goto out;
589    }
590    param->data_size = param->data_start + needed;
591
592    iter_info.param_size = param_size;
593    iter_info.old_vers = NULL;
594    iter_info.vers = vers;
595    iter_info.flags = 0;
596    iter_info.end = (char *)vers+len;
597
598    /*
599     * Now loop through filling out the names & versions.
600     */
601    dm_target_iterate(list_version_get_info, &iter_info);
602    param->flags |= iter_info.flags;
603
604 out:
605    return 0;
606}
607
608static int check_name(const char *name)
609{
610    if (strchr(name, '/')) {
611        DMWARN("invalid device name");
612        return -EINVAL;
613    }
614
615    return 0;
616}
617
618/*
619 * On successful return, the caller must not attempt to acquire
620 * _hash_lock without first calling dm_table_put, because dm_table_destroy
621 * waits for this dm_table_put and could be called under this lock.
622 */
623static struct dm_table *dm_get_inactive_table(struct mapped_device *md)
624{
625    struct hash_cell *hc;
626    struct dm_table *table = NULL;
627
628    down_read(&_hash_lock);
629    hc = dm_get_mdptr(md);
630    if (!hc || hc->md != md) {
631        DMWARN("device has been removed from the dev hash table.");
632        goto out;
633    }
634
635    table = hc->new_map;
636    if (table)
637        dm_table_get(table);
638
639out:
640    up_read(&_hash_lock);
641
642    return table;
643}
644
645static struct dm_table *dm_get_live_or_inactive_table(struct mapped_device *md,
646                              struct dm_ioctl *param)
647{
648    return (param->flags & DM_QUERY_INACTIVE_TABLE_FLAG) ?
649        dm_get_inactive_table(md) : dm_get_live_table(md);
650}
651
652/*
653 * Fills in a dm_ioctl structure, ready for sending back to
654 * userland.
655 */
656static void __dev_status(struct mapped_device *md, struct dm_ioctl *param)
657{
658    struct gendisk *disk = dm_disk(md);
659    struct dm_table *table;
660
661    param->flags &= ~(DM_SUSPEND_FLAG | DM_READONLY_FLAG |
662              DM_ACTIVE_PRESENT_FLAG);
663
664    if (dm_suspended_md(md))
665        param->flags |= DM_SUSPEND_FLAG;
666
667    param->dev = huge_encode_dev(disk_devt(disk));
668
669    /*
670     * Yes, this will be out of date by the time it gets back
671     * to userland, but it is still very useful for
672     * debugging.
673     */
674    param->open_count = dm_open_count(md);
675
676    param->event_nr = dm_get_event_nr(md);
677    param->target_count = 0;
678
679    table = dm_get_live_table(md);
680    if (table) {
681        if (!(param->flags & DM_QUERY_INACTIVE_TABLE_FLAG)) {
682            if (get_disk_ro(disk))
683                param->flags |= DM_READONLY_FLAG;
684            param->target_count = dm_table_get_num_targets(table);
685        }
686        dm_table_put(table);
687
688        param->flags |= DM_ACTIVE_PRESENT_FLAG;
689    }
690
691    if (param->flags & DM_QUERY_INACTIVE_TABLE_FLAG) {
692        table = dm_get_inactive_table(md);
693        if (table) {
694            if (!(dm_table_get_mode(table) & FMODE_WRITE))
695                param->flags |= DM_READONLY_FLAG;
696            param->target_count = dm_table_get_num_targets(table);
697            dm_table_put(table);
698        }
699    }
700}
701
702static int dev_create(struct dm_ioctl *param, size_t param_size)
703{
704    int r, m = DM_ANY_MINOR;
705    struct mapped_device *md;
706
707    r = check_name(param->name);
708    if (r)
709        return r;
710
711    if (param->flags & DM_PERSISTENT_DEV_FLAG)
712        m = MINOR(huge_decode_dev(param->dev));
713
714    r = dm_create(m, &md);
715    if (r)
716        return r;
717
718    r = dm_hash_insert(param->name, *param->uuid ? param->uuid : NULL, md);
719    if (r) {
720        dm_put(md);
721        dm_destroy(md);
722        return r;
723    }
724
725    param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
726
727    __dev_status(md, param);
728
729    dm_put(md);
730
731    return 0;
732}
733
734/*
735 * Always use UUID for lookups if it's present, otherwise use name or dev.
736 */
737static struct hash_cell *__find_device_hash_cell(struct dm_ioctl *param)
738{
739    struct hash_cell *hc = NULL;
740
741    if (*param->uuid) {
742        if (*param->name || param->dev)
743            return NULL;
744
745        hc = __get_uuid_cell(param->uuid);
746        if (!hc)
747            return NULL;
748    } else if (*param->name) {
749        if (param->dev)
750            return NULL;
751
752        hc = __get_name_cell(param->name);
753        if (!hc)
754            return NULL;
755    } else if (param->dev) {
756        hc = __get_dev_cell(param->dev);
757        if (!hc)
758            return NULL;
759    } else
760        return NULL;
761
762    /*
763     * Sneakily write in both the name and the uuid
764     * while we have the cell.
765     */
766    strlcpy(param->name, hc->name, sizeof(param->name));
767    if (hc->uuid)
768        strlcpy(param->uuid, hc->uuid, sizeof(param->uuid));
769    else
770        param->uuid[0] = '\0';
771
772    if (hc->new_map)
773        param->flags |= DM_INACTIVE_PRESENT_FLAG;
774    else
775        param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
776
777    return hc;
778}
779
780static struct mapped_device *find_device(struct dm_ioctl *param)
781{
782    struct hash_cell *hc;
783    struct mapped_device *md = NULL;
784
785    down_read(&_hash_lock);
786    hc = __find_device_hash_cell(param);
787    if (hc)
788        md = hc->md;
789    up_read(&_hash_lock);
790
791    return md;
792}
793
794static int dev_remove(struct dm_ioctl *param, size_t param_size)
795{
796    struct hash_cell *hc;
797    struct mapped_device *md;
798    int r;
799
800    down_write(&_hash_lock);
801    hc = __find_device_hash_cell(param);
802
803    if (!hc) {
804        DMDEBUG_LIMIT("device doesn't appear to be in the dev hash table.");
805        up_write(&_hash_lock);
806        return -ENXIO;
807    }
808
809    md = hc->md;
810
811    /*
812     * Ensure the device is not open and nothing further can open it.
813     */
814    r = dm_lock_for_deletion(md);
815    if (r) {
816        DMDEBUG_LIMIT("unable to remove open device %s", hc->name);
817        up_write(&_hash_lock);
818        dm_put(md);
819        return r;
820    }
821
822    __hash_remove(hc);
823    up_write(&_hash_lock);
824
825    if (!dm_kobject_uevent(md, KOBJ_REMOVE, param->event_nr))
826        param->flags |= DM_UEVENT_GENERATED_FLAG;
827
828    dm_put(md);
829    dm_destroy(md);
830    return 0;
831}
832
833/*
834 * Check a string doesn't overrun the chunk of
835 * memory we copied from userland.
836 */
837static int invalid_str(char *str, void *end)
838{
839    while ((void *) str < end)
840        if (!*str++)
841            return 0;
842
843    return -EINVAL;
844}
845
846static int dev_rename(struct dm_ioctl *param, size_t param_size)
847{
848    int r;
849    char *new_data = (char *) param + param->data_start;
850    struct mapped_device *md;
851    unsigned change_uuid = (param->flags & DM_UUID_FLAG) ? 1 : 0;
852
853    if (new_data < param->data ||
854        invalid_str(new_data, (void *) param + param_size) ||
855        strlen(new_data) > (change_uuid ? DM_UUID_LEN - 1 : DM_NAME_LEN - 1)) {
856        DMWARN("Invalid new mapped device name or uuid string supplied.");
857        return -EINVAL;
858    }
859
860    if (!change_uuid) {
861        r = check_name(new_data);
862        if (r)
863            return r;
864    }
865
866    md = dm_hash_rename(param, new_data);
867    if (IS_ERR(md))
868        return PTR_ERR(md);
869
870    __dev_status(md, param);
871    dm_put(md);
872
873    return 0;
874}
875
876static int dev_set_geometry(struct dm_ioctl *param, size_t param_size)
877{
878    int r = -EINVAL, x;
879    struct mapped_device *md;
880    struct hd_geometry geometry;
881    unsigned long indata[4];
882    char *geostr = (char *) param + param->data_start;
883    char dummy;
884
885    md = find_device(param);
886    if (!md)
887        return -ENXIO;
888
889    if (geostr < param->data ||
890        invalid_str(geostr, (void *) param + param_size)) {
891        DMWARN("Invalid geometry supplied.");
892        goto out;
893    }
894
895    x = sscanf(geostr, "%lu %lu %lu %lu%c", indata,
896           indata + 1, indata + 2, indata + 3, &dummy);
897
898    if (x != 4) {
899        DMWARN("Unable to interpret geometry settings.");
900        goto out;
901    }
902
903    if (indata[0] > 65535 || indata[1] > 255 ||
904        indata[2] > 255 || indata[3] > ULONG_MAX) {
905        DMWARN("Geometry exceeds range limits.");
906        goto out;
907    }
908
909    geometry.cylinders = indata[0];
910    geometry.heads = indata[1];
911    geometry.sectors = indata[2];
912    geometry.start = indata[3];
913
914    r = dm_set_geometry(md, &geometry);
915
916    param->data_size = 0;
917
918out:
919    dm_put(md);
920    return r;
921}
922
923static int do_suspend(struct dm_ioctl *param)
924{
925    int r = 0;
926    unsigned suspend_flags = DM_SUSPEND_LOCKFS_FLAG;
927    struct mapped_device *md;
928
929    md = find_device(param);
930    if (!md)
931        return -ENXIO;
932
933    if (param->flags & DM_SKIP_LOCKFS_FLAG)
934        suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG;
935    if (param->flags & DM_NOFLUSH_FLAG)
936        suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG;
937
938    if (!dm_suspended_md(md)) {
939        r = dm_suspend(md, suspend_flags);
940        if (r)
941            goto out;
942    }
943
944    __dev_status(md, param);
945
946out:
947    dm_put(md);
948
949    return r;
950}
951
952static int do_resume(struct dm_ioctl *param)
953{
954    int r = 0;
955    unsigned suspend_flags = DM_SUSPEND_LOCKFS_FLAG;
956    struct hash_cell *hc;
957    struct mapped_device *md;
958    struct dm_table *new_map, *old_map = NULL;
959
960    down_write(&_hash_lock);
961
962    hc = __find_device_hash_cell(param);
963    if (!hc) {
964        DMDEBUG_LIMIT("device doesn't appear to be in the dev hash table.");
965        up_write(&_hash_lock);
966        return -ENXIO;
967    }
968
969    md = hc->md;
970
971    new_map = hc->new_map;
972    hc->new_map = NULL;
973    param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
974
975    up_write(&_hash_lock);
976
977    /* Do we need to load a new map ? */
978    if (new_map) {
979        /* Suspend if it isn't already suspended */
980        if (param->flags & DM_SKIP_LOCKFS_FLAG)
981            suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG;
982        if (param->flags & DM_NOFLUSH_FLAG)
983            suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG;
984        if (!dm_suspended_md(md))
985            dm_suspend(md, suspend_flags);
986
987        old_map = dm_swap_table(md, new_map);
988        if (IS_ERR(old_map)) {
989            dm_table_destroy(new_map);
990            dm_put(md);
991            return PTR_ERR(old_map);
992        }
993
994        if (dm_table_get_mode(new_map) & FMODE_WRITE)
995            set_disk_ro(dm_disk(md), 0);
996        else
997            set_disk_ro(dm_disk(md), 1);
998    }
999
1000    if (dm_suspended_md(md)) {
1001        r = dm_resume(md);
1002        if (!r && !dm_kobject_uevent(md, KOBJ_CHANGE, param->event_nr))
1003            param->flags |= DM_UEVENT_GENERATED_FLAG;
1004    }
1005
1006    if (old_map)
1007        dm_table_destroy(old_map);
1008
1009    if (!r)
1010        __dev_status(md, param);
1011
1012    dm_put(md);
1013    return r;
1014}
1015
1016/*
1017 * Set or unset the suspension state of a device.
1018 * If the device already is in the requested state we just return its status.
1019 */
1020static int dev_suspend(struct dm_ioctl *param, size_t param_size)
1021{
1022    if (param->flags & DM_SUSPEND_FLAG)
1023        return do_suspend(param);
1024
1025    return do_resume(param);
1026}
1027
1028/*
1029 * Copies device info back to user space, used by
1030 * the create and info ioctls.
1031 */
1032static int dev_status(struct dm_ioctl *param, size_t param_size)
1033{
1034    struct mapped_device *md;
1035
1036    md = find_device(param);
1037    if (!md)
1038        return -ENXIO;
1039
1040    __dev_status(md, param);
1041    dm_put(md);
1042
1043    return 0;
1044}
1045
1046/*
1047 * Build up the status struct for each target
1048 */
1049static void retrieve_status(struct dm_table *table,
1050                struct dm_ioctl *param, size_t param_size)
1051{
1052    unsigned int i, num_targets;
1053    struct dm_target_spec *spec;
1054    char *outbuf, *outptr;
1055    status_type_t type;
1056    size_t remaining, len, used = 0;
1057    unsigned status_flags = 0;
1058
1059    outptr = outbuf = get_result_buffer(param, param_size, &len);
1060
1061    if (param->flags & DM_STATUS_TABLE_FLAG)
1062        type = STATUSTYPE_TABLE;
1063    else
1064        type = STATUSTYPE_INFO;
1065
1066    /* Get all the target info */
1067    num_targets = dm_table_get_num_targets(table);
1068    for (i = 0; i < num_targets; i++) {
1069        struct dm_target *ti = dm_table_get_target(table, i);
1070        size_t l;
1071
1072        remaining = len - (outptr - outbuf);
1073        if (remaining <= sizeof(struct dm_target_spec)) {
1074            param->flags |= DM_BUFFER_FULL_FLAG;
1075            break;
1076        }
1077
1078        spec = (struct dm_target_spec *) outptr;
1079
1080        spec->status = 0;
1081        spec->sector_start = ti->begin;
1082        spec->length = ti->len;
1083        strncpy(spec->target_type, ti->type->name,
1084            sizeof(spec->target_type));
1085
1086        outptr += sizeof(struct dm_target_spec);
1087        remaining = len - (outptr - outbuf);
1088        if (remaining <= 0) {
1089            param->flags |= DM_BUFFER_FULL_FLAG;
1090            break;
1091        }
1092
1093        /* Get the status/table string from the target driver */
1094        if (ti->type->status) {
1095            if (param->flags & DM_NOFLUSH_FLAG)
1096                status_flags |= DM_STATUS_NOFLUSH_FLAG;
1097            ti->type->status(ti, type, status_flags, outptr, remaining);
1098        } else
1099            outptr[0] = '\0';
1100
1101        l = strlen(outptr) + 1;
1102        if (l == remaining) {
1103            param->flags |= DM_BUFFER_FULL_FLAG;
1104            break;
1105        }
1106
1107        outptr += l;
1108        used = param->data_start + (outptr - outbuf);
1109
1110        outptr = align_ptr(outptr);
1111        spec->next = outptr - outbuf;
1112    }
1113
1114    if (used)
1115        param->data_size = used;
1116
1117    param->target_count = num_targets;
1118}
1119
1120/*
1121 * Wait for a device to report an event
1122 */
1123static int dev_wait(struct dm_ioctl *param, size_t param_size)
1124{
1125    int r = 0;
1126    struct mapped_device *md;
1127    struct dm_table *table;
1128
1129    md = find_device(param);
1130    if (!md)
1131        return -ENXIO;
1132
1133    /*
1134     * Wait for a notification event
1135     */
1136    if (dm_wait_event(md, param->event_nr)) {
1137        r = -ERESTARTSYS;
1138        goto out;
1139    }
1140
1141    /*
1142     * The userland program is going to want to know what
1143     * changed to trigger the event, so we may as well tell
1144     * him and save an ioctl.
1145     */
1146    __dev_status(md, param);
1147
1148    table = dm_get_live_or_inactive_table(md, param);
1149    if (table) {
1150        retrieve_status(table, param, param_size);
1151        dm_table_put(table);
1152    }
1153
1154out:
1155    dm_put(md);
1156
1157    return r;
1158}
1159
1160static inline fmode_t get_mode(struct dm_ioctl *param)
1161{
1162    fmode_t mode = FMODE_READ | FMODE_WRITE;
1163
1164    if (param->flags & DM_READONLY_FLAG)
1165        mode = FMODE_READ;
1166
1167    return mode;
1168}
1169
1170static int next_target(struct dm_target_spec *last, uint32_t next, void *end,
1171               struct dm_target_spec **spec, char **target_params)
1172{
1173    *spec = (struct dm_target_spec *) ((unsigned char *) last + next);
1174    *target_params = (char *) (*spec + 1);
1175
1176    if (*spec < (last + 1))
1177        return -EINVAL;
1178
1179    return invalid_str(*target_params, end);
1180}
1181
1182static int populate_table(struct dm_table *table,
1183              struct dm_ioctl *param, size_t param_size)
1184{
1185    int r;
1186    unsigned int i = 0;
1187    struct dm_target_spec *spec = (struct dm_target_spec *) param;
1188    uint32_t next = param->data_start;
1189    void *end = (void *) param + param_size;
1190    char *target_params;
1191
1192    if (!param->target_count) {
1193        DMWARN("populate_table: no targets specified");
1194        return -EINVAL;
1195    }
1196
1197    for (i = 0; i < param->target_count; i++) {
1198
1199        r = next_target(spec, next, end, &spec, &target_params);
1200        if (r) {
1201            DMWARN("unable to find target");
1202            return r;
1203        }
1204
1205        r = dm_table_add_target(table, spec->target_type,
1206                    (sector_t) spec->sector_start,
1207                    (sector_t) spec->length,
1208                    target_params);
1209        if (r) {
1210            DMWARN("error adding target to table");
1211            return r;
1212        }
1213
1214        next = spec->next;
1215    }
1216
1217    return dm_table_complete(table);
1218}
1219
1220static int table_load(struct dm_ioctl *param, size_t param_size)
1221{
1222    int r;
1223    struct hash_cell *hc;
1224    struct dm_table *t;
1225    struct mapped_device *md;
1226    struct target_type *immutable_target_type;
1227
1228    md = find_device(param);
1229    if (!md)
1230        return -ENXIO;
1231
1232    r = dm_table_create(&t, get_mode(param), param->target_count, md);
1233    if (r)
1234        goto out;
1235
1236    r = populate_table(t, param, param_size);
1237    if (r) {
1238        dm_table_destroy(t);
1239        goto out;
1240    }
1241
1242    immutable_target_type = dm_get_immutable_target_type(md);
1243    if (immutable_target_type &&
1244        (immutable_target_type != dm_table_get_immutable_target_type(t))) {
1245        DMWARN("can't replace immutable target type %s",
1246               immutable_target_type->name);
1247        dm_table_destroy(t);
1248        r = -EINVAL;
1249        goto out;
1250    }
1251
1252    /* Protect md->type and md->queue against concurrent table loads. */
1253    dm_lock_md_type(md);
1254    if (dm_get_md_type(md) == DM_TYPE_NONE)
1255        /* Initial table load: acquire type of table. */
1256        dm_set_md_type(md, dm_table_get_type(t));
1257    else if (dm_get_md_type(md) != dm_table_get_type(t)) {
1258        DMWARN("can't change device type after initial table load.");
1259        dm_table_destroy(t);
1260        dm_unlock_md_type(md);
1261        r = -EINVAL;
1262        goto out;
1263    }
1264
1265    /* setup md->queue to reflect md's type (may block) */
1266    r = dm_setup_md_queue(md);
1267    if (r) {
1268        DMWARN("unable to set up device queue for new table.");
1269        dm_table_destroy(t);
1270        dm_unlock_md_type(md);
1271        goto out;
1272    }
1273    dm_unlock_md_type(md);
1274
1275    /* stage inactive table */
1276    down_write(&_hash_lock);
1277    hc = dm_get_mdptr(md);
1278    if (!hc || hc->md != md) {
1279        DMWARN("device has been removed from the dev hash table.");
1280        dm_table_destroy(t);
1281        up_write(&_hash_lock);
1282        r = -ENXIO;
1283        goto out;
1284    }
1285
1286    if (hc->new_map)
1287        dm_table_destroy(hc->new_map);
1288    hc->new_map = t;
1289    up_write(&_hash_lock);
1290
1291    param->flags |= DM_INACTIVE_PRESENT_FLAG;
1292    __dev_status(md, param);
1293
1294out:
1295    dm_put(md);
1296
1297    return r;
1298}
1299
1300static int table_clear(struct dm_ioctl *param, size_t param_size)
1301{
1302    struct hash_cell *hc;
1303    struct mapped_device *md;
1304
1305    down_write(&_hash_lock);
1306
1307    hc = __find_device_hash_cell(param);
1308    if (!hc) {
1309        DMDEBUG_LIMIT("device doesn't appear to be in the dev hash table.");
1310        up_write(&_hash_lock);
1311        return -ENXIO;
1312    }
1313
1314    if (hc->new_map) {
1315        dm_table_destroy(hc->new_map);
1316        hc->new_map = NULL;
1317    }
1318
1319    param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
1320
1321    __dev_status(hc->md, param);
1322    md = hc->md;
1323    up_write(&_hash_lock);
1324    dm_put(md);
1325
1326    return 0;
1327}
1328
1329/*
1330 * Retrieves a list of devices used by a particular dm device.
1331 */
1332static void retrieve_deps(struct dm_table *table,
1333              struct dm_ioctl *param, size_t param_size)
1334{
1335    unsigned int count = 0;
1336    struct list_head *tmp;
1337    size_t len, needed;
1338    struct dm_dev_internal *dd;
1339    struct dm_target_deps *deps;
1340
1341    deps = get_result_buffer(param, param_size, &len);
1342
1343    /*
1344     * Count the devices.
1345     */
1346    list_for_each (tmp, dm_table_get_devices(table))
1347        count++;
1348
1349    /*
1350     * Check we have enough space.
1351     */
1352    needed = sizeof(*deps) + (sizeof(*deps->dev) * count);
1353    if (len < needed) {
1354        param->flags |= DM_BUFFER_FULL_FLAG;
1355        return;
1356    }
1357
1358    /*
1359     * Fill in the devices.
1360     */
1361    deps->count = count;
1362    count = 0;
1363    list_for_each_entry (dd, dm_table_get_devices(table), list)
1364        deps->dev[count++] = huge_encode_dev(dd->dm_dev.bdev->bd_dev);
1365
1366    param->data_size = param->data_start + needed;
1367}
1368
1369static int table_deps(struct dm_ioctl *param, size_t param_size)
1370{
1371    struct mapped_device *md;
1372    struct dm_table *table;
1373
1374    md = find_device(param);
1375    if (!md)
1376        return -ENXIO;
1377
1378    __dev_status(md, param);
1379
1380    table = dm_get_live_or_inactive_table(md, param);
1381    if (table) {
1382        retrieve_deps(table, param, param_size);
1383        dm_table_put(table);
1384    }
1385
1386    dm_put(md);
1387
1388    return 0;
1389}
1390
1391/*
1392 * Return the status of a device as a text string for each
1393 * target.
1394 */
1395static int table_status(struct dm_ioctl *param, size_t param_size)
1396{
1397    struct mapped_device *md;
1398    struct dm_table *table;
1399
1400    md = find_device(param);
1401    if (!md)
1402        return -ENXIO;
1403
1404    __dev_status(md, param);
1405
1406    table = dm_get_live_or_inactive_table(md, param);
1407    if (table) {
1408        retrieve_status(table, param, param_size);
1409        dm_table_put(table);
1410    }
1411
1412    dm_put(md);
1413
1414    return 0;
1415}
1416
1417static bool buffer_test_overflow(char *result, unsigned maxlen)
1418{
1419    return !maxlen || strlen(result) + 1 >= maxlen;
1420}
1421
1422/*
1423 * Process device-mapper dependent messages.
1424 * Returns a number <= 1 if message was processed by device mapper.
1425 * Returns 2 if message should be delivered to the target.
1426 */
1427static int message_for_md(struct mapped_device *md, unsigned argc, char **argv,
1428              char *result, unsigned maxlen)
1429{
1430    return 2;
1431}
1432
1433/*
1434 * Pass a message to the target that's at the supplied device offset.
1435 */
1436static int target_message(struct dm_ioctl *param, size_t param_size)
1437{
1438    int r, argc;
1439    char **argv;
1440    struct mapped_device *md;
1441    struct dm_table *table;
1442    struct dm_target *ti;
1443    struct dm_target_msg *tmsg = (void *) param + param->data_start;
1444    size_t maxlen;
1445    char *result = get_result_buffer(param, param_size, &maxlen);
1446
1447    md = find_device(param);
1448    if (!md)
1449        return -ENXIO;
1450
1451    if (tmsg < (struct dm_target_msg *) param->data ||
1452        invalid_str(tmsg->message, (void *) param + param_size)) {
1453        DMWARN("Invalid target message parameters.");
1454        r = -EINVAL;
1455        goto out;
1456    }
1457
1458    r = dm_split_args(&argc, &argv, tmsg->message);
1459    if (r) {
1460        DMWARN("Failed to split target message parameters");
1461        goto out;
1462    }
1463
1464    if (!argc) {
1465        DMWARN("Empty message received.");
1466        goto out_argv;
1467    }
1468
1469    r = message_for_md(md, argc, argv, result, maxlen);
1470    if (r <= 1)
1471        goto out_argv;
1472
1473    table = dm_get_live_table(md);
1474    if (!table)
1475        goto out_argv;
1476
1477    if (dm_deleting_md(md)) {
1478        r = -ENXIO;
1479        goto out_table;
1480    }
1481
1482    ti = dm_table_find_target(table, tmsg->sector);
1483    if (!dm_target_is_valid(ti)) {
1484        DMWARN("Target message sector outside device.");
1485        r = -EINVAL;
1486    } else if (ti->type->message)
1487        r = ti->type->message(ti, argc, argv);
1488    else {
1489        DMWARN("Target type does not support messages");
1490        r = -EINVAL;
1491    }
1492
1493 out_table:
1494    dm_table_put(table);
1495 out_argv:
1496    kfree(argv);
1497 out:
1498    if (r >= 0)
1499        __dev_status(md, param);
1500
1501    if (r == 1) {
1502        param->flags |= DM_DATA_OUT_FLAG;
1503        if (buffer_test_overflow(result, maxlen))
1504            param->flags |= DM_BUFFER_FULL_FLAG;
1505        else
1506            param->data_size = param->data_start + strlen(result) + 1;
1507        r = 0;
1508    }
1509
1510    dm_put(md);
1511    return r;
1512}
1513
1514/*
1515 * The ioctl parameter block consists of two parts, a dm_ioctl struct
1516 * followed by a data buffer. This flag is set if the second part,
1517 * which has a variable size, is not used by the function processing
1518 * the ioctl.
1519 */
1520#define IOCTL_FLAGS_NO_PARAMS 1
1521
1522/*-----------------------------------------------------------------
1523 * Implementation of open/close/ioctl on the special char
1524 * device.
1525 *---------------------------------------------------------------*/
1526static ioctl_fn lookup_ioctl(unsigned int cmd, int *ioctl_flags)
1527{
1528    static struct {
1529        int cmd;
1530        int flags;
1531        ioctl_fn fn;
1532    } _ioctls[] = {
1533        {DM_VERSION_CMD, 0, NULL}, /* version is dealt with elsewhere */
1534        {DM_REMOVE_ALL_CMD, IOCTL_FLAGS_NO_PARAMS, remove_all},
1535        {DM_LIST_DEVICES_CMD, 0, list_devices},
1536
1537        {DM_DEV_CREATE_CMD, IOCTL_FLAGS_NO_PARAMS, dev_create},
1538        {DM_DEV_REMOVE_CMD, IOCTL_FLAGS_NO_PARAMS, dev_remove},
1539        {DM_DEV_RENAME_CMD, 0, dev_rename},
1540        {DM_DEV_SUSPEND_CMD, IOCTL_FLAGS_NO_PARAMS, dev_suspend},
1541        {DM_DEV_STATUS_CMD, IOCTL_FLAGS_NO_PARAMS, dev_status},
1542        {DM_DEV_WAIT_CMD, 0, dev_wait},
1543
1544        {DM_TABLE_LOAD_CMD, 0, table_load},
1545        {DM_TABLE_CLEAR_CMD, IOCTL_FLAGS_NO_PARAMS, table_clear},
1546        {DM_TABLE_DEPS_CMD, 0, table_deps},
1547        {DM_TABLE_STATUS_CMD, 0, table_status},
1548
1549        {DM_LIST_VERSIONS_CMD, 0, list_versions},
1550
1551        {DM_TARGET_MSG_CMD, 0, target_message},
1552        {DM_DEV_SET_GEOMETRY_CMD, 0, dev_set_geometry}
1553    };
1554
1555    if (unlikely(cmd >= ARRAY_SIZE(_ioctls)))
1556        return NULL;
1557
1558    *ioctl_flags = _ioctls[cmd].flags;
1559    return _ioctls[cmd].fn;
1560}
1561
1562/*
1563 * As well as checking the version compatibility this always
1564 * copies the kernel interface version out.
1565 */
1566static int check_version(unsigned int cmd, struct dm_ioctl __user *user)
1567{
1568    uint32_t version[3];
1569    int r = 0;
1570
1571    if (copy_from_user(version, user->version, sizeof(version)))
1572        return -EFAULT;
1573
1574    if ((DM_VERSION_MAJOR != version[0]) ||
1575        (DM_VERSION_MINOR < version[1])) {
1576        DMWARN("ioctl interface mismatch: "
1577               "kernel(%u.%u.%u), user(%u.%u.%u), cmd(%d)",
1578               DM_VERSION_MAJOR, DM_VERSION_MINOR,
1579               DM_VERSION_PATCHLEVEL,
1580               version[0], version[1], version[2], cmd);
1581        r = -EINVAL;
1582    }
1583
1584    /*
1585     * Fill in the kernel version.
1586     */
1587    version[0] = DM_VERSION_MAJOR;
1588    version[1] = DM_VERSION_MINOR;
1589    version[2] = DM_VERSION_PATCHLEVEL;
1590    if (copy_to_user(user->version, version, sizeof(version)))
1591        return -EFAULT;
1592
1593    return r;
1594}
1595
1596#define DM_PARAMS_KMALLOC 0x0001 /* Params alloced with kmalloc */
1597#define DM_PARAMS_VMALLOC 0x0002 /* Params alloced with vmalloc */
1598#define DM_WIPE_BUFFER 0x0010 /* Wipe input buffer before returning from ioctl */
1599
1600static void free_params(struct dm_ioctl *param, size_t param_size, int param_flags)
1601{
1602    if (param_flags & DM_WIPE_BUFFER)
1603        memset(param, 0, param_size);
1604
1605    if (param_flags & DM_PARAMS_KMALLOC)
1606        kfree(param);
1607    if (param_flags & DM_PARAMS_VMALLOC)
1608        vfree(param);
1609}
1610
1611static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl *param_kernel,
1612               int ioctl_flags,
1613               struct dm_ioctl **param, int *param_flags)
1614{
1615    struct dm_ioctl *dmi;
1616    int secure_data;
1617    const size_t minimum_data_size = sizeof(*param_kernel) - sizeof(param_kernel->data);
1618
1619    if (copy_from_user(param_kernel, user, minimum_data_size))
1620        return -EFAULT;
1621
1622    if (param_kernel->data_size < minimum_data_size)
1623        return -EINVAL;
1624
1625    secure_data = param_kernel->flags & DM_SECURE_DATA_FLAG;
1626
1627    *param_flags = secure_data ? DM_WIPE_BUFFER : 0;
1628
1629    if (ioctl_flags & IOCTL_FLAGS_NO_PARAMS) {
1630        dmi = param_kernel;
1631        dmi->data_size = minimum_data_size;
1632        goto data_copied;
1633    }
1634
1635    /*
1636     * Try to avoid low memory issues when a device is suspended.
1637     * Use kmalloc() rather than vmalloc() when we can.
1638     */
1639    dmi = NULL;
1640    if (param_kernel->data_size <= KMALLOC_MAX_SIZE) {
1641        dmi = kmalloc(param_kernel->data_size, GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN);
1642        if (dmi)
1643            *param_flags |= DM_PARAMS_KMALLOC;
1644    }
1645
1646    if (!dmi) {
1647        dmi = __vmalloc(param_kernel->data_size, GFP_NOIO | __GFP_REPEAT | __GFP_HIGH, PAGE_KERNEL);
1648        if (dmi)
1649            *param_flags |= DM_PARAMS_VMALLOC;
1650    }
1651
1652    if (!dmi) {
1653        if (secure_data && clear_user(user, param_kernel->data_size))
1654            return -EFAULT;
1655        return -ENOMEM;
1656    }
1657
1658    if (copy_from_user(dmi, user, param_kernel->data_size))
1659        goto bad;
1660
1661data_copied:
1662    /*
1663     * Abort if something changed the ioctl data while it was being copied.
1664     */
1665    if (dmi->data_size != param_kernel->data_size) {
1666        DMERR("rejecting ioctl: data size modified while processing parameters");
1667        goto bad;
1668    }
1669
1670    /* Wipe the user buffer so we do not return it to userspace */
1671    if (secure_data && clear_user(user, param_kernel->data_size))
1672        goto bad;
1673
1674    *param = dmi;
1675    return 0;
1676
1677bad:
1678    free_params(dmi, param_kernel->data_size, *param_flags);
1679
1680    return -EFAULT;
1681}
1682
1683static int validate_params(uint cmd, struct dm_ioctl *param)
1684{
1685    /* Always clear this flag */
1686    param->flags &= ~DM_BUFFER_FULL_FLAG;
1687    param->flags &= ~DM_UEVENT_GENERATED_FLAG;
1688    param->flags &= ~DM_SECURE_DATA_FLAG;
1689    param->flags &= ~DM_DATA_OUT_FLAG;
1690
1691    /* Ignores parameters */
1692    if (cmd == DM_REMOVE_ALL_CMD ||
1693        cmd == DM_LIST_DEVICES_CMD ||
1694        cmd == DM_LIST_VERSIONS_CMD)
1695        return 0;
1696
1697    if ((cmd == DM_DEV_CREATE_CMD)) {
1698        if (!*param->name) {
1699            DMWARN("name not supplied when creating device");
1700            return -EINVAL;
1701        }
1702    } else if ((*param->uuid && *param->name)) {
1703        DMWARN("only supply one of name or uuid, cmd(%u)", cmd);
1704        return -EINVAL;
1705    }
1706
1707    /* Ensure strings are terminated */
1708    param->name[DM_NAME_LEN - 1] = '\0';
1709    param->uuid[DM_UUID_LEN - 1] = '\0';
1710
1711    return 0;
1712}
1713
1714static int ctl_ioctl(uint command, struct dm_ioctl __user *user)
1715{
1716    int r = 0;
1717    int ioctl_flags;
1718    int param_flags;
1719    unsigned int cmd;
1720    struct dm_ioctl *uninitialized_var(param);
1721    ioctl_fn fn = NULL;
1722    size_t input_param_size;
1723    struct dm_ioctl param_kernel;
1724
1725    /* only root can play with this */
1726    if (!capable(CAP_SYS_ADMIN))
1727        return -EACCES;
1728
1729    if (_IOC_TYPE(command) != DM_IOCTL)
1730        return -ENOTTY;
1731
1732    cmd = _IOC_NR(command);
1733
1734    /*
1735     * Check the interface version passed in. This also
1736     * writes out the kernel's interface version.
1737     */
1738    r = check_version(cmd, user);
1739    if (r)
1740        return r;
1741
1742    /*
1743     * Nothing more to do for the version command.
1744     */
1745    if (cmd == DM_VERSION_CMD)
1746        return 0;
1747
1748    fn = lookup_ioctl(cmd, &ioctl_flags);
1749    if (!fn) {
1750        DMWARN("dm_ctl_ioctl: unknown command 0x%x", command);
1751        return -ENOTTY;
1752    }
1753
1754    /*
1755     * Copy the parameters into kernel space.
1756     */
1757    r = copy_params(user, &param_kernel, ioctl_flags, &param, &param_flags);
1758
1759    if (r)
1760        return r;
1761
1762    input_param_size = param->data_size;
1763    r = validate_params(cmd, param);
1764    if (r)
1765        goto out;
1766
1767    param->data_size = sizeof(*param);
1768    r = fn(param, input_param_size);
1769
1770    if (unlikely(param->flags & DM_BUFFER_FULL_FLAG) &&
1771        unlikely(ioctl_flags & IOCTL_FLAGS_NO_PARAMS))
1772        DMERR("ioctl %d tried to output some data but has IOCTL_FLAGS_NO_PARAMS set", cmd);
1773
1774    /*
1775     * Copy the results back to userland.
1776     */
1777    if (!r && copy_to_user(user, param, param->data_size))
1778        r = -EFAULT;
1779
1780out:
1781    free_params(param, input_param_size, param_flags);
1782    return r;
1783}
1784
1785static long dm_ctl_ioctl(struct file *file, uint command, ulong u)
1786{
1787    return (long)ctl_ioctl(command, (struct dm_ioctl __user *)u);
1788}
1789
1790#ifdef CONFIG_COMPAT
1791static long dm_compat_ctl_ioctl(struct file *file, uint command, ulong u)
1792{
1793    return (long)dm_ctl_ioctl(file, command, (ulong) compat_ptr(u));
1794}
1795#else
1796#define dm_compat_ctl_ioctl NULL
1797#endif
1798
1799static const struct file_operations _ctl_fops = {
1800    .open = nonseekable_open,
1801    .unlocked_ioctl = dm_ctl_ioctl,
1802    .compat_ioctl = dm_compat_ctl_ioctl,
1803    .owner = THIS_MODULE,
1804    .llseek = noop_llseek,
1805};
1806
1807static struct miscdevice _dm_misc = {
1808    .minor = MAPPER_CTRL_MINOR,
1809    .name = DM_NAME,
1810    .nodename = DM_DIR "/" DM_CONTROL_NODE,
1811    .fops = &_ctl_fops
1812};
1813
1814MODULE_ALIAS_MISCDEV(MAPPER_CTRL_MINOR);
1815MODULE_ALIAS("devname:" DM_DIR "/" DM_CONTROL_NODE);
1816
1817/*
1818 * Create misc character device and link to DM_DIR/control.
1819 */
1820int __init dm_interface_init(void)
1821{
1822    int r;
1823
1824    r = dm_hash_init();
1825    if (r)
1826        return r;
1827
1828    r = misc_register(&_dm_misc);
1829    if (r) {
1830        DMERR("misc_register failed for control device");
1831        dm_hash_exit();
1832        return r;
1833    }
1834
1835    DMINFO("%d.%d.%d%s initialised: %s", DM_VERSION_MAJOR,
1836           DM_VERSION_MINOR, DM_VERSION_PATCHLEVEL, DM_VERSION_EXTRA,
1837           DM_DRIVER_EMAIL);
1838    return 0;
1839}
1840
1841void dm_interface_exit(void)
1842{
1843    if (misc_deregister(&_dm_misc) < 0)
1844        DMERR("misc_deregister failed for control device");
1845
1846    dm_hash_exit();
1847}
1848
1849/**
1850 * dm_copy_name_and_uuid - Copy mapped device name & uuid into supplied buffers
1851 * @md: Pointer to mapped_device
1852 * @name: Buffer (size DM_NAME_LEN) for name
1853 * @uuid: Buffer (size DM_UUID_LEN) for uuid or empty string if uuid not defined
1854 */
1855int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid)
1856{
1857    int r = 0;
1858    struct hash_cell *hc;
1859
1860    if (!md)
1861        return -ENXIO;
1862
1863    mutex_lock(&dm_hash_cells_mutex);
1864    hc = dm_get_mdptr(md);
1865    if (!hc || hc->md != md) {
1866        r = -ENXIO;
1867        goto out;
1868    }
1869
1870    if (name)
1871        strcpy(name, hc->name);
1872    if (uuid)
1873        strcpy(uuid, hc->uuid ? : "");
1874
1875out:
1876    mutex_unlock(&dm_hash_cells_mutex);
1877
1878    return r;
1879}
1880

Archive Download this file



interactive