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/smp_lock.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;
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)
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);
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        default:
96            return -EINVAL;
97    }
98}
99
100static int blkdev_reread_part(struct block_device *bdev)
101{
102    struct gendisk *disk = bdev->bd_disk;
103    int res;
104
105    if (!disk_partitionable(disk) || bdev != bdev->bd_contains)
106        return -EINVAL;
107    if (!capable(CAP_SYS_ADMIN))
108        return -EACCES;
109    if (!mutex_trylock(&bdev->bd_mutex))
110        return -EBUSY;
111    res = rescan_partitions(disk, bdev);
112    mutex_unlock(&bdev->bd_mutex);
113    return res;
114}
115
116static int blk_ioctl_discard(struct block_device *bdev, uint64_t start,
117                 uint64_t len)
118{
119    if (start & 511)
120        return -EINVAL;
121    if (len & 511)
122        return -EINVAL;
123    start >>= 9;
124    len >>= 9;
125
126    if (start + len > (bdev->bd_inode->i_size >> 9))
127        return -EINVAL;
128    return blkdev_issue_discard(bdev, start, len, GFP_KERNEL,
129                    BLKDEV_IFL_WAIT);
130}
131
132static int put_ushort(unsigned long arg, unsigned short val)
133{
134    return put_user(val, (unsigned short __user *)arg);
135}
136
137static int put_int(unsigned long arg, int val)
138{
139    return put_user(val, (int __user *)arg);
140}
141
142static int put_uint(unsigned long arg, unsigned int val)
143{
144    return put_user(val, (unsigned int __user *)arg);
145}
146
147static int put_long(unsigned long arg, long val)
148{
149    return put_user(val, (long __user *)arg);
150}
151
152static int put_ulong(unsigned long arg, unsigned long val)
153{
154    return put_user(val, (unsigned long __user *)arg);
155}
156
157static int put_u64(unsigned long arg, u64 val)
158{
159    return put_user(val, (u64 __user *)arg);
160}
161
162int __blkdev_driver_ioctl(struct block_device *bdev, fmode_t mode,
163            unsigned cmd, unsigned long arg)
164{
165    struct gendisk *disk = bdev->bd_disk;
166    int ret;
167
168    if (disk->fops->ioctl)
169        return disk->fops->ioctl(bdev, mode, cmd, arg);
170
171    if (disk->fops->locked_ioctl) {
172        lock_kernel();
173        ret = disk->fops->locked_ioctl(bdev, mode, cmd, arg);
174        unlock_kernel();
175        return ret;
176    }
177
178    return -ENOTTY;
179}
180/*
181 * For the record: _GPL here is only because somebody decided to slap it
182 * on the previous export. Sheer idiocy, since it wasn't copyrightable
183 * at all and could be open-coded without any exports by anybody who cares.
184 */
185EXPORT_SYMBOL_GPL(__blkdev_driver_ioctl);
186
187/*
188 * always keep this in sync with compat_blkdev_ioctl() and
189 * compat_blkdev_locked_ioctl()
190 */
191int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
192            unsigned long arg)
193{
194    struct gendisk *disk = bdev->bd_disk;
195    struct backing_dev_info *bdi;
196    loff_t size;
197    int ret, n;
198
199    switch(cmd) {
200    case BLKFLSBUF:
201        if (!capable(CAP_SYS_ADMIN))
202            return -EACCES;
203
204        ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
205        /* -EINVAL to handle old uncorrected drivers */
206        if (ret != -EINVAL && ret != -ENOTTY)
207            return ret;
208
209        lock_kernel();
210        fsync_bdev(bdev);
211        invalidate_bdev(bdev);
212        unlock_kernel();
213        return 0;
214
215    case BLKROSET:
216        ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
217        /* -EINVAL to handle old uncorrected drivers */
218        if (ret != -EINVAL && ret != -ENOTTY)
219            return ret;
220        if (!capable(CAP_SYS_ADMIN))
221            return -EACCES;
222        if (get_user(n, (int __user *)(arg)))
223            return -EFAULT;
224        lock_kernel();
225        set_device_ro(bdev, n);
226        unlock_kernel();
227        return 0;
228
229    case BLKDISCARD: {
230        uint64_t range[2];
231
232        if (!(mode & FMODE_WRITE))
233            return -EBADF;
234
235        if (copy_from_user(range, (void __user *)arg, sizeof(range)))
236            return -EFAULT;
237
238        return blk_ioctl_discard(bdev, range[0], range[1]);
239    }
240
241    case HDIO_GETGEO: {
242        struct hd_geometry geo;
243
244        if (!arg)
245            return -EINVAL;
246        if (!disk->fops->getgeo)
247            return -ENOTTY;
248
249        /*
250         * We need to set the startsect first, the driver may
251         * want to override it.
252         */
253        geo.start = get_start_sect(bdev);
254        ret = disk->fops->getgeo(bdev, &geo);
255        if (ret)
256            return ret;
257        if (copy_to_user((struct hd_geometry __user *)arg, &geo,
258                    sizeof(geo)))
259            return -EFAULT;
260        return 0;
261    }
262    case BLKRAGET:
263    case BLKFRAGET:
264        if (!arg)
265            return -EINVAL;
266        bdi = blk_get_backing_dev_info(bdev);
267        if (bdi == NULL)
268            return -ENOTTY;
269        return put_long(arg, (bdi->ra_pages * PAGE_CACHE_SIZE) / 512);
270    case BLKROGET:
271        return put_int(arg, bdev_read_only(bdev) != 0);
272    case BLKBSZGET: /* get block device soft block size (cf. BLKSSZGET) */
273        return put_int(arg, block_size(bdev));
274    case BLKSSZGET: /* get block device logical block size */
275        return put_int(arg, bdev_logical_block_size(bdev));
276    case BLKPBSZGET: /* get block device physical block size */
277        return put_uint(arg, bdev_physical_block_size(bdev));
278    case BLKIOMIN:
279        return put_uint(arg, bdev_io_min(bdev));
280    case BLKIOOPT:
281        return put_uint(arg, bdev_io_opt(bdev));
282    case BLKALIGNOFF:
283        return put_int(arg, bdev_alignment_offset(bdev));
284    case BLKDISCARDZEROES:
285        return put_uint(arg, bdev_discard_zeroes_data(bdev));
286    case BLKSECTGET:
287        return put_ushort(arg, queue_max_sectors(bdev_get_queue(bdev)));
288    case BLKRASET:
289    case BLKFRASET:
290        if(!capable(CAP_SYS_ADMIN))
291            return -EACCES;
292        bdi = blk_get_backing_dev_info(bdev);
293        if (bdi == NULL)
294            return -ENOTTY;
295        bdi->ra_pages = (arg * 512) / PAGE_CACHE_SIZE;
296        return 0;
297    case BLKBSZSET:
298        /* set the logical block size */
299        if (!capable(CAP_SYS_ADMIN))
300            return -EACCES;
301        if (!arg)
302            return -EINVAL;
303        if (get_user(n, (int __user *) arg))
304            return -EFAULT;
305        if (!(mode & FMODE_EXCL) && bd_claim(bdev, &bdev) < 0)
306            return -EBUSY;
307        ret = set_blocksize(bdev, n);
308        if (!(mode & FMODE_EXCL))
309            bd_release(bdev);
310        return ret;
311    case BLKPG:
312        lock_kernel();
313        ret = blkpg_ioctl(bdev, (struct blkpg_ioctl_arg __user *) arg);
314        unlock_kernel();
315        break;
316    case BLKRRPART:
317        lock_kernel();
318        ret = blkdev_reread_part(bdev);
319        unlock_kernel();
320        break;
321    case BLKGETSIZE:
322        size = bdev->bd_inode->i_size;
323        if ((size >> 9) > ~0UL)
324            return -EFBIG;
325        return put_ulong(arg, size >> 9);
326    case BLKGETSIZE64:
327        return put_u64(arg, bdev->bd_inode->i_size);
328    case BLKTRACESTART:
329    case BLKTRACESTOP:
330    case BLKTRACESETUP:
331    case BLKTRACETEARDOWN:
332        lock_kernel();
333        ret = blk_trace_ioctl(bdev, cmd, (char __user *) arg);
334        unlock_kernel();
335        break;
336    default:
337        ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
338    }
339    return ret;
340}
341EXPORT_SYMBOL_GPL(blkdev_ioctl);
342

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