Root/block/ioctl.c

1#include <linux/capability.h>
2#include <linux/blkdev.h>
3#include <linux/export.h>
4#include <linux/gfp.h>
5#include <linux/blkpg.h>
6#include <linux/hdreg.h>
7#include <linux/backing-dev.h>
8#include <linux/fs.h>
9#include <linux/blktrace_api.h>
10#include <asm/uaccess.h>
11
12static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user *arg)
13{
14    struct block_device *bdevp;
15    struct gendisk *disk;
16    struct hd_struct *part, *lpart;
17    struct blkpg_ioctl_arg a;
18    struct blkpg_partition p;
19    struct disk_part_iter piter;
20    long long start, length;
21    int partno;
22
23    if (!capable(CAP_SYS_ADMIN))
24        return -EACCES;
25    if (copy_from_user(&a, arg, sizeof(struct blkpg_ioctl_arg)))
26        return -EFAULT;
27    if (copy_from_user(&p, a.data, sizeof(struct blkpg_partition)))
28        return -EFAULT;
29    disk = bdev->bd_disk;
30    if (bdev != bdev->bd_contains)
31        return -EINVAL;
32    partno = p.pno;
33    if (partno <= 0)
34        return -EINVAL;
35    switch (a.op) {
36        case BLKPG_ADD_PARTITION:
37            start = p.start >> 9;
38            length = p.length >> 9;
39            /* check for fit in a hd_struct */
40            if (sizeof(sector_t) == sizeof(long) &&
41                sizeof(long long) > sizeof(long)) {
42                long pstart = start, plength = length;
43                if (pstart != start || plength != length
44                    || pstart < 0 || plength < 0 || partno > 65535)
45                    return -EINVAL;
46            }
47
48            mutex_lock(&bdev->bd_mutex);
49
50            /* overlap? */
51            disk_part_iter_init(&piter, disk,
52                        DISK_PITER_INCL_EMPTY);
53            while ((part = disk_part_iter_next(&piter))) {
54                if (!(start + length <= part->start_sect ||
55                      start >= part->start_sect + part->nr_sects)) {
56                    disk_part_iter_exit(&piter);
57                    mutex_unlock(&bdev->bd_mutex);
58                    return -EBUSY;
59                }
60            }
61            disk_part_iter_exit(&piter);
62
63            /* all seems OK */
64            part = add_partition(disk, partno, start, length,
65                         ADDPART_FLAG_NONE, NULL);
66            mutex_unlock(&bdev->bd_mutex);
67            return IS_ERR(part) ? PTR_ERR(part) : 0;
68        case BLKPG_DEL_PARTITION:
69            part = disk_get_part(disk, partno);
70            if (!part)
71                return -ENXIO;
72
73            bdevp = bdget(part_devt(part));
74            disk_put_part(part);
75            if (!bdevp)
76                return -ENOMEM;
77
78            mutex_lock(&bdevp->bd_mutex);
79            if (bdevp->bd_openers) {
80                mutex_unlock(&bdevp->bd_mutex);
81                bdput(bdevp);
82                return -EBUSY;
83            }
84            /* all seems OK */
85            fsync_bdev(bdevp);
86            invalidate_bdev(bdevp);
87
88            mutex_lock_nested(&bdev->bd_mutex, 1);
89            delete_partition(disk, partno);
90            mutex_unlock(&bdev->bd_mutex);
91            mutex_unlock(&bdevp->bd_mutex);
92            bdput(bdevp);
93
94            return 0;
95        case BLKPG_RESIZE_PARTITION:
96            start = p.start >> 9;
97            /* new length of partition in bytes */
98            length = p.length >> 9;
99            /* check for fit in a hd_struct */
100            if (sizeof(sector_t) == sizeof(long) &&
101                sizeof(long long) > sizeof(long)) {
102                long pstart = start, plength = length;
103                if (pstart != start || plength != length
104                    || pstart < 0 || plength < 0)
105                    return -EINVAL;
106            }
107            part = disk_get_part(disk, partno);
108            if (!part)
109                return -ENXIO;
110            bdevp = bdget(part_devt(part));
111            if (!bdevp) {
112                disk_put_part(part);
113                return -ENOMEM;
114            }
115            mutex_lock(&bdevp->bd_mutex);
116            mutex_lock_nested(&bdev->bd_mutex, 1);
117            if (start != part->start_sect) {
118                mutex_unlock(&bdevp->bd_mutex);
119                mutex_unlock(&bdev->bd_mutex);
120                bdput(bdevp);
121                disk_put_part(part);
122                return -EINVAL;
123            }
124            /* overlap? */
125            disk_part_iter_init(&piter, disk,
126                        DISK_PITER_INCL_EMPTY);
127            while ((lpart = disk_part_iter_next(&piter))) {
128                if (lpart->partno != partno &&
129                   !(start + length <= lpart->start_sect ||
130                   start >= lpart->start_sect + lpart->nr_sects)
131                   ) {
132                    disk_part_iter_exit(&piter);
133                    mutex_unlock(&bdevp->bd_mutex);
134                    mutex_unlock(&bdev->bd_mutex);
135                    bdput(bdevp);
136                    disk_put_part(part);
137                    return -EBUSY;
138                }
139            }
140            disk_part_iter_exit(&piter);
141            part_nr_sects_write(part, (sector_t)length);
142            i_size_write(bdevp->bd_inode, p.length);
143            mutex_unlock(&bdevp->bd_mutex);
144            mutex_unlock(&bdev->bd_mutex);
145            bdput(bdevp);
146            disk_put_part(part);
147            return 0;
148        default:
149            return -EINVAL;
150    }
151}
152
153static int blkdev_reread_part(struct block_device *bdev)
154{
155    struct gendisk *disk = bdev->bd_disk;
156    int res;
157
158    if (!disk_part_scan_enabled(disk) || bdev != bdev->bd_contains)
159        return -EINVAL;
160    if (!capable(CAP_SYS_ADMIN))
161        return -EACCES;
162    if (!mutex_trylock(&bdev->bd_mutex))
163        return -EBUSY;
164    res = rescan_partitions(disk, bdev);
165    mutex_unlock(&bdev->bd_mutex);
166    return res;
167}
168
169static int blk_ioctl_discard(struct block_device *bdev, uint64_t start,
170                 uint64_t len, int secure)
171{
172    unsigned long flags = 0;
173
174    if (start & 511)
175        return -EINVAL;
176    if (len & 511)
177        return -EINVAL;
178    start >>= 9;
179    len >>= 9;
180
181    if (start + len > (i_size_read(bdev->bd_inode) >> 9))
182        return -EINVAL;
183    if (secure)
184        flags |= BLKDEV_DISCARD_SECURE;
185    return blkdev_issue_discard(bdev, start, len, GFP_KERNEL, flags);
186}
187
188static int put_ushort(unsigned long arg, unsigned short val)
189{
190    return put_user(val, (unsigned short __user *)arg);
191}
192
193static int put_int(unsigned long arg, int val)
194{
195    return put_user(val, (int __user *)arg);
196}
197
198static int put_uint(unsigned long arg, unsigned int val)
199{
200    return put_user(val, (unsigned int __user *)arg);
201}
202
203static int put_long(unsigned long arg, long val)
204{
205    return put_user(val, (long __user *)arg);
206}
207
208static int put_ulong(unsigned long arg, unsigned long val)
209{
210    return put_user(val, (unsigned long __user *)arg);
211}
212
213static int put_u64(unsigned long arg, u64 val)
214{
215    return put_user(val, (u64 __user *)arg);
216}
217
218int __blkdev_driver_ioctl(struct block_device *bdev, fmode_t mode,
219            unsigned cmd, unsigned long arg)
220{
221    struct gendisk *disk = bdev->bd_disk;
222
223    if (disk->fops->ioctl)
224        return disk->fops->ioctl(bdev, mode, cmd, arg);
225
226    return -ENOTTY;
227}
228/*
229 * For the record: _GPL here is only because somebody decided to slap it
230 * on the previous export. Sheer idiocy, since it wasn't copyrightable
231 * at all and could be open-coded without any exports by anybody who cares.
232 */
233EXPORT_SYMBOL_GPL(__blkdev_driver_ioctl);
234
235/*
236 * Is it an unrecognized ioctl? The correct returns are either
237 * ENOTTY (final) or ENOIOCTLCMD ("I don't know this one, try a
238 * fallback"). ENOIOCTLCMD gets turned into ENOTTY by the ioctl
239 * code before returning.
240 *
241 * Confused drivers sometimes return EINVAL, which is wrong. It
242 * means "I understood the ioctl command, but the parameters to
243 * it were wrong".
244 *
245 * We should aim to just fix the broken drivers, the EINVAL case
246 * should go away.
247 */
248static inline int is_unrecognized_ioctl(int ret)
249{
250    return ret == -EINVAL ||
251        ret == -ENOTTY ||
252        ret == -ENOIOCTLCMD;
253}
254
255/*
256 * always keep this in sync with compat_blkdev_ioctl()
257 */
258int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
259            unsigned long arg)
260{
261    struct gendisk *disk = bdev->bd_disk;
262    struct backing_dev_info *bdi;
263    loff_t size;
264    int ret, n;
265
266    switch(cmd) {
267    case BLKFLSBUF:
268        if (!capable(CAP_SYS_ADMIN))
269            return -EACCES;
270
271        ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
272        if (!is_unrecognized_ioctl(ret))
273            return ret;
274
275        fsync_bdev(bdev);
276        invalidate_bdev(bdev);
277        return 0;
278
279    case BLKROSET:
280        ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
281        if (!is_unrecognized_ioctl(ret))
282            return ret;
283        if (!capable(CAP_SYS_ADMIN))
284            return -EACCES;
285        if (get_user(n, (int __user *)(arg)))
286            return -EFAULT;
287        set_device_ro(bdev, n);
288        return 0;
289
290    case BLKDISCARD:
291    case BLKSECDISCARD: {
292        uint64_t range[2];
293
294        if (!(mode & FMODE_WRITE))
295            return -EBADF;
296
297        if (copy_from_user(range, (void __user *)arg, sizeof(range)))
298            return -EFAULT;
299
300        return blk_ioctl_discard(bdev, range[0], range[1],
301                     cmd == BLKSECDISCARD);
302    }
303
304    case HDIO_GETGEO: {
305        struct hd_geometry geo;
306
307        if (!arg)
308            return -EINVAL;
309        if (!disk->fops->getgeo)
310            return -ENOTTY;
311
312        /*
313         * We need to set the startsect first, the driver may
314         * want to override it.
315         */
316        memset(&geo, 0, sizeof(geo));
317        geo.start = get_start_sect(bdev);
318        ret = disk->fops->getgeo(bdev, &geo);
319        if (ret)
320            return ret;
321        if (copy_to_user((struct hd_geometry __user *)arg, &geo,
322                    sizeof(geo)))
323            return -EFAULT;
324        return 0;
325    }
326    case BLKRAGET:
327    case BLKFRAGET:
328        if (!arg)
329            return -EINVAL;
330        bdi = blk_get_backing_dev_info(bdev);
331        if (bdi == NULL)
332            return -ENOTTY;
333        return put_long(arg, (bdi->ra_pages * PAGE_CACHE_SIZE) / 512);
334    case BLKROGET:
335        return put_int(arg, bdev_read_only(bdev) != 0);
336    case BLKBSZGET: /* get block device soft block size (cf. BLKSSZGET) */
337        return put_int(arg, block_size(bdev));
338    case BLKSSZGET: /* get block device logical block size */
339        return put_int(arg, bdev_logical_block_size(bdev));
340    case BLKPBSZGET: /* get block device physical block size */
341        return put_uint(arg, bdev_physical_block_size(bdev));
342    case BLKIOMIN:
343        return put_uint(arg, bdev_io_min(bdev));
344    case BLKIOOPT:
345        return put_uint(arg, bdev_io_opt(bdev));
346    case BLKALIGNOFF:
347        return put_int(arg, bdev_alignment_offset(bdev));
348    case BLKDISCARDZEROES:
349        return put_uint(arg, bdev_discard_zeroes_data(bdev));
350    case BLKSECTGET:
351        return put_ushort(arg, queue_max_sectors(bdev_get_queue(bdev)));
352    case BLKROTATIONAL:
353        return put_ushort(arg, !blk_queue_nonrot(bdev_get_queue(bdev)));
354    case BLKRASET:
355    case BLKFRASET:
356        if(!capable(CAP_SYS_ADMIN))
357            return -EACCES;
358        bdi = blk_get_backing_dev_info(bdev);
359        if (bdi == NULL)
360            return -ENOTTY;
361        bdi->ra_pages = (arg * 512) / PAGE_CACHE_SIZE;
362        return 0;
363    case BLKBSZSET:
364        /* set the logical block size */
365        if (!capable(CAP_SYS_ADMIN))
366            return -EACCES;
367        if (!arg)
368            return -EINVAL;
369        if (get_user(n, (int __user *) arg))
370            return -EFAULT;
371        if (!(mode & FMODE_EXCL)) {
372            bdgrab(bdev);
373            if (blkdev_get(bdev, mode | FMODE_EXCL, &bdev) < 0)
374                return -EBUSY;
375        }
376        ret = set_blocksize(bdev, n);
377        if (!(mode & FMODE_EXCL))
378            blkdev_put(bdev, mode | FMODE_EXCL);
379        return ret;
380    case BLKPG:
381        ret = blkpg_ioctl(bdev, (struct blkpg_ioctl_arg __user *) arg);
382        break;
383    case BLKRRPART:
384        ret = blkdev_reread_part(bdev);
385        break;
386    case BLKGETSIZE:
387        size = i_size_read(bdev->bd_inode);
388        if ((size >> 9) > ~0UL)
389            return -EFBIG;
390        return put_ulong(arg, size >> 9);
391    case BLKGETSIZE64:
392        return put_u64(arg, i_size_read(bdev->bd_inode));
393    case BLKTRACESTART:
394    case BLKTRACESTOP:
395    case BLKTRACESETUP:
396    case BLKTRACETEARDOWN:
397        ret = blk_trace_ioctl(bdev, cmd, (char __user *) arg);
398        break;
399    default:
400        ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
401    }
402    return ret;
403}
404EXPORT_SYMBOL_GPL(blkdev_ioctl);
405

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