Root/block/ioctl.c

1#include <linux/capability.h>
2#include <linux/blkdev.h>
3#include <linux/blkpg.h>
4#include <linux/hdreg.h>
5#include <linux/backing-dev.h>
6#include <linux/buffer_head.h>
7#include <linux/smp_lock.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);
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)
117{
118    if (start & 511)
119        return -EINVAL;
120    if (len & 511)
121        return -EINVAL;
122    start >>= 9;
123    len >>= 9;
124
125    if (start + len > (bdev->bd_inode->i_size >> 9))
126        return -EINVAL;
127    return blkdev_issue_discard(bdev, start, len, GFP_KERNEL,
128                    DISCARD_FL_WAIT);
129}
130
131static int put_ushort(unsigned long arg, unsigned short val)
132{
133    return put_user(val, (unsigned short __user *)arg);
134}
135
136static int put_int(unsigned long arg, int val)
137{
138    return put_user(val, (int __user *)arg);
139}
140
141static int put_uint(unsigned long arg, unsigned int val)
142{
143    return put_user(val, (unsigned int __user *)arg);
144}
145
146static int put_long(unsigned long arg, long val)
147{
148    return put_user(val, (long __user *)arg);
149}
150
151static int put_ulong(unsigned long arg, unsigned long val)
152{
153    return put_user(val, (unsigned long __user *)arg);
154}
155
156static int put_u64(unsigned long arg, u64 val)
157{
158    return put_user(val, (u64 __user *)arg);
159}
160
161int __blkdev_driver_ioctl(struct block_device *bdev, fmode_t mode,
162            unsigned cmd, unsigned long arg)
163{
164    struct gendisk *disk = bdev->bd_disk;
165    int ret;
166
167    if (disk->fops->ioctl)
168        return disk->fops->ioctl(bdev, mode, cmd, arg);
169
170    if (disk->fops->locked_ioctl) {
171        lock_kernel();
172        ret = disk->fops->locked_ioctl(bdev, mode, cmd, arg);
173        unlock_kernel();
174        return ret;
175    }
176
177    return -ENOTTY;
178}
179/*
180 * For the record: _GPL here is only because somebody decided to slap it
181 * on the previous export. Sheer idiocy, since it wasn't copyrightable
182 * at all and could be open-coded without any exports by anybody who cares.
183 */
184EXPORT_SYMBOL_GPL(__blkdev_driver_ioctl);
185
186/*
187 * always keep this in sync with compat_blkdev_ioctl() and
188 * compat_blkdev_locked_ioctl()
189 */
190int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
191            unsigned long arg)
192{
193    struct gendisk *disk = bdev->bd_disk;
194    struct backing_dev_info *bdi;
195    loff_t size;
196    int ret, n;
197
198    switch(cmd) {
199    case BLKFLSBUF:
200        if (!capable(CAP_SYS_ADMIN))
201            return -EACCES;
202
203        ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
204        /* -EINVAL to handle old uncorrected drivers */
205        if (ret != -EINVAL && ret != -ENOTTY)
206            return ret;
207
208        lock_kernel();
209        fsync_bdev(bdev);
210        invalidate_bdev(bdev);
211        unlock_kernel();
212        return 0;
213
214    case BLKROSET:
215        ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
216        /* -EINVAL to handle old uncorrected drivers */
217        if (ret != -EINVAL && ret != -ENOTTY)
218            return ret;
219        if (!capable(CAP_SYS_ADMIN))
220            return -EACCES;
221        if (get_user(n, (int __user *)(arg)))
222            return -EFAULT;
223        lock_kernel();
224        set_device_ro(bdev, n);
225        unlock_kernel();
226        return 0;
227
228    case BLKDISCARD: {
229        uint64_t range[2];
230
231        if (!(mode & FMODE_WRITE))
232            return -EBADF;
233
234        if (copy_from_user(range, (void __user *)arg, sizeof(range)))
235            return -EFAULT;
236
237        return blk_ioctl_discard(bdev, range[0], range[1]);
238    }
239
240    case HDIO_GETGEO: {
241        struct hd_geometry geo;
242
243        if (!arg)
244            return -EINVAL;
245        if (!disk->fops->getgeo)
246            return -ENOTTY;
247
248        /*
249         * We need to set the startsect first, the driver may
250         * want to override it.
251         */
252        geo.start = get_start_sect(bdev);
253        ret = disk->fops->getgeo(bdev, &geo);
254        if (ret)
255            return ret;
256        if (copy_to_user((struct hd_geometry __user *)arg, &geo,
257                    sizeof(geo)))
258            return -EFAULT;
259        return 0;
260    }
261    case BLKRAGET:
262    case BLKFRAGET:
263        if (!arg)
264            return -EINVAL;
265        bdi = blk_get_backing_dev_info(bdev);
266        if (bdi == NULL)
267            return -ENOTTY;
268        return put_long(arg, (bdi->ra_pages * PAGE_CACHE_SIZE) / 512);
269    case BLKROGET:
270        return put_int(arg, bdev_read_only(bdev) != 0);
271    case BLKBSZGET: /* get block device soft block size (cf. BLKSSZGET) */
272        return put_int(arg, block_size(bdev));
273    case BLKSSZGET: /* get block device logical block size */
274        return put_int(arg, bdev_logical_block_size(bdev));
275    case BLKPBSZGET: /* get block device physical block size */
276        return put_uint(arg, bdev_physical_block_size(bdev));
277    case BLKIOMIN:
278        return put_uint(arg, bdev_io_min(bdev));
279    case BLKIOOPT:
280        return put_uint(arg, bdev_io_opt(bdev));
281    case BLKALIGNOFF:
282        return put_int(arg, bdev_alignment_offset(bdev));
283    case BLKSECTGET:
284        return put_ushort(arg, queue_max_sectors(bdev_get_queue(bdev)));
285    case BLKRASET:
286    case BLKFRASET:
287        if(!capable(CAP_SYS_ADMIN))
288            return -EACCES;
289        bdi = blk_get_backing_dev_info(bdev);
290        if (bdi == NULL)
291            return -ENOTTY;
292        bdi->ra_pages = (arg * 512) / PAGE_CACHE_SIZE;
293        return 0;
294    case BLKBSZSET:
295        /* set the logical block size */
296        if (!capable(CAP_SYS_ADMIN))
297            return -EACCES;
298        if (!arg)
299            return -EINVAL;
300        if (get_user(n, (int __user *) arg))
301            return -EFAULT;
302        if (!(mode & FMODE_EXCL) && bd_claim(bdev, &bdev) < 0)
303            return -EBUSY;
304        ret = set_blocksize(bdev, n);
305        if (!(mode & FMODE_EXCL))
306            bd_release(bdev);
307        return ret;
308    case BLKPG:
309        lock_kernel();
310        ret = blkpg_ioctl(bdev, (struct blkpg_ioctl_arg __user *) arg);
311        unlock_kernel();
312        break;
313    case BLKRRPART:
314        lock_kernel();
315        ret = blkdev_reread_part(bdev);
316        unlock_kernel();
317        break;
318    case BLKGETSIZE:
319        size = bdev->bd_inode->i_size;
320        if ((size >> 9) > ~0UL)
321            return -EFBIG;
322        return put_ulong(arg, size >> 9);
323    case BLKGETSIZE64:
324        return put_u64(arg, bdev->bd_inode->i_size);
325    case BLKTRACESTART:
326    case BLKTRACESTOP:
327    case BLKTRACESETUP:
328    case BLKTRACETEARDOWN:
329        lock_kernel();
330        ret = blk_trace_ioctl(bdev, cmd, (char __user *) arg);
331        unlock_kernel();
332        break;
333    default:
334        ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
335    }
336    return ret;
337}
338EXPORT_SYMBOL_GPL(blkdev_ioctl);
339

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