Root/block/ioctl.c

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

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