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1/*
2 * posix-clock.c - support for dynamic clock devices
3 *
4 * Copyright (C) 2010 OMICRON electronics GmbH
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19 */
20#include <linux/device.h>
21#include <linux/export.h>
22#include <linux/file.h>
23#include <linux/posix-clock.h>
24#include <linux/slab.h>
25#include <linux/syscalls.h>
26#include <linux/uaccess.h>
27
28#include "posix-timers.h"
29
30static void delete_clock(struct kref *kref);
31
32/*
33 * Returns NULL if the posix_clock instance attached to 'fp' is old and stale.
34 */
35static struct posix_clock *get_posix_clock(struct file *fp)
36{
37 struct posix_clock *clk = fp->private_data;
38
39 down_read(&clk->rwsem);
40
41 if (!clk->zombie)
42 return clk;
43
44 up_read(&clk->rwsem);
45
46 return NULL;
47}
48
49static void put_posix_clock(struct posix_clock *clk)
50{
51 up_read(&clk->rwsem);
52}
53
54static ssize_t posix_clock_read(struct file *fp, char __user *buf,
55 size_t count, loff_t *ppos)
56{
57 struct posix_clock *clk = get_posix_clock(fp);
58 int err = -EINVAL;
59
60 if (!clk)
61 return -ENODEV;
62
63 if (clk->ops.read)
64 err = clk->ops.read(clk, fp->f_flags, buf, count);
65
66 put_posix_clock(clk);
67
68 return err;
69}
70
71static __poll_t posix_clock_poll(struct file *fp, poll_table *wait)
72{
73 struct posix_clock *clk = get_posix_clock(fp);
74 __poll_t result = 0;
75
76 if (!clk)
77 return EPOLLERR;
78
79 if (clk->ops.poll)
80 result = clk->ops.poll(clk, fp, wait);
81
82 put_posix_clock(clk);
83
84 return result;
85}
86
87static long posix_clock_ioctl(struct file *fp,
88 unsigned int cmd, unsigned long arg)
89{
90 struct posix_clock *clk = get_posix_clock(fp);
91 int err = -ENOTTY;
92
93 if (!clk)
94 return -ENODEV;
95
96 if (clk->ops.ioctl)
97 err = clk->ops.ioctl(clk, cmd, arg);
98
99 put_posix_clock(clk);
100
101 return err;
102}
103
104#ifdef CONFIG_COMPAT
105static long posix_clock_compat_ioctl(struct file *fp,
106 unsigned int cmd, unsigned long arg)
107{
108 struct posix_clock *clk = get_posix_clock(fp);
109 int err = -ENOTTY;
110
111 if (!clk)
112 return -ENODEV;
113
114 if (clk->ops.ioctl)
115 err = clk->ops.ioctl(clk, cmd, arg);
116
117 put_posix_clock(clk);
118
119 return err;
120}
121#endif
122
123static int posix_clock_open(struct inode *inode, struct file *fp)
124{
125 int err;
126 struct posix_clock *clk =
127 container_of(inode->i_cdev, struct posix_clock, cdev);
128
129 down_read(&clk->rwsem);
130
131 if (clk->zombie) {
132 err = -ENODEV;
133 goto out;
134 }
135 if (clk->ops.open)
136 err = clk->ops.open(clk, fp->f_mode);
137 else
138 err = 0;
139
140 if (!err) {
141 kref_get(&clk->kref);
142 fp->private_data = clk;
143 }
144out:
145 up_read(&clk->rwsem);
146 return err;
147}
148
149static int posix_clock_release(struct inode *inode, struct file *fp)
150{
151 struct posix_clock *clk = fp->private_data;
152 int err = 0;
153
154 if (clk->ops.release)
155 err = clk->ops.release(clk);
156
157 kref_put(&clk->kref, delete_clock);
158
159 fp->private_data = NULL;
160
161 return err;
162}
163
164static const struct file_operations posix_clock_file_operations = {
165 .owner = THIS_MODULE,
166 .llseek = no_llseek,
167 .read = posix_clock_read,
168 .poll = posix_clock_poll,
169 .unlocked_ioctl = posix_clock_ioctl,
170 .open = posix_clock_open,
171 .release = posix_clock_release,
172#ifdef CONFIG_COMPAT
173 .compat_ioctl = posix_clock_compat_ioctl,
174#endif
175};
176
177int posix_clock_register(struct posix_clock *clk, dev_t devid)
178{
179 int err;
180
181 kref_init(&clk->kref);
182 init_rwsem(&clk->rwsem);
183
184 cdev_init(&clk->cdev, &posix_clock_file_operations);
185 clk->cdev.owner = clk->ops.owner;
186 err = cdev_add(&clk->cdev, devid, 1);
187
188 return err;
189}
190EXPORT_SYMBOL_GPL(posix_clock_register);
191
192static void delete_clock(struct kref *kref)
193{
194 struct posix_clock *clk = container_of(kref, struct posix_clock, kref);
195
196 if (clk->release)
197 clk->release(clk);
198}
199
200void posix_clock_unregister(struct posix_clock *clk)
201{
202 cdev_del(&clk->cdev);
203
204 down_write(&clk->rwsem);
205 clk->zombie = true;
206 up_write(&clk->rwsem);
207
208 kref_put(&clk->kref, delete_clock);
209}
210EXPORT_SYMBOL_GPL(posix_clock_unregister);
211
212struct posix_clock_desc {
213 struct file *fp;
214 struct posix_clock *clk;
215};
216
217static int get_clock_desc(const clockid_t id, struct posix_clock_desc *cd)
218{
219 struct file *fp = fget(clockid_to_fd(id));
220 int err = -EINVAL;
221
222 if (!fp)
223 return err;
224
225 if (fp->f_op->open != posix_clock_open || !fp->private_data)
226 goto out;
227
228 cd->fp = fp;
229 cd->clk = get_posix_clock(fp);
230
231 err = cd->clk ? 0 : -ENODEV;
232out:
233 if (err)
234 fput(fp);
235 return err;
236}
237
238static void put_clock_desc(struct posix_clock_desc *cd)
239{
240 put_posix_clock(cd->clk);
241 fput(cd->fp);
242}
243
244static int pc_clock_adjtime(clockid_t id, struct timex *tx)
245{
246 struct posix_clock_desc cd;
247 int err;
248
249 err = get_clock_desc(id, &cd);
250 if (err)
251 return err;
252
253 if ((cd.fp->f_mode & FMODE_WRITE) == 0) {
254 err = -EACCES;
255 goto out;
256 }
257
258 if (cd.clk->ops.clock_adjtime)
259 err = cd.clk->ops.clock_adjtime(cd.clk, tx);
260 else
261 err = -EOPNOTSUPP;
262out:
263 put_clock_desc(&cd);
264
265 return err;
266}
267
268static int pc_clock_gettime(clockid_t id, struct timespec64 *ts)
269{
270 struct posix_clock_desc cd;
271 int err;
272
273 err = get_clock_desc(id, &cd);
274 if (err)
275 return err;
276
277 if (cd.clk->ops.clock_gettime)
278 err = cd.clk->ops.clock_gettime(cd.clk, ts);
279 else
280 err = -EOPNOTSUPP;
281
282 put_clock_desc(&cd);
283
284 return err;
285}
286
287static int pc_clock_getres(clockid_t id, struct timespec64 *ts)
288{
289 struct posix_clock_desc cd;
290 int err;
291
292 err = get_clock_desc(id, &cd);
293 if (err)
294 return err;
295
296 if (cd.clk->ops.clock_getres)
297 err = cd.clk->ops.clock_getres(cd.clk, ts);
298 else
299 err = -EOPNOTSUPP;
300
301 put_clock_desc(&cd);
302
303 return err;
304}
305
306static int pc_clock_settime(clockid_t id, const struct timespec64 *ts)
307{
308 struct posix_clock_desc cd;
309 int err;
310
311 err = get_clock_desc(id, &cd);
312 if (err)
313 return err;
314
315 if ((cd.fp->f_mode & FMODE_WRITE) == 0) {
316 err = -EACCES;
317 goto out;
318 }
319
320 if (cd.clk->ops.clock_settime)
321 err = cd.clk->ops.clock_settime(cd.clk, ts);
322 else
323 err = -EOPNOTSUPP;
324out:
325 put_clock_desc(&cd);
326
327 return err;
328}
329
330const struct k_clock clock_posix_dynamic = {
331 .clock_getres = pc_clock_getres,
332 .clock_set = pc_clock_settime,
333 .clock_get = pc_clock_gettime,
334 .clock_adj = pc_clock_adjtime,
335};
1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Support for dynamic clock devices
4 *
5 * Copyright (C) 2010 OMICRON electronics GmbH
6 */
7#include <linux/device.h>
8#include <linux/export.h>
9#include <linux/file.h>
10#include <linux/posix-clock.h>
11#include <linux/slab.h>
12#include <linux/syscalls.h>
13#include <linux/uaccess.h>
14
15#include "posix-timers.h"
16
17/*
18 * Returns NULL if the posix_clock instance attached to 'fp' is old and stale.
19 */
20static struct posix_clock *get_posix_clock(struct file *fp)
21{
22 struct posix_clock_context *pccontext = fp->private_data;
23 struct posix_clock *clk = pccontext->clk;
24
25 down_read(&clk->rwsem);
26
27 if (!clk->zombie)
28 return clk;
29
30 up_read(&clk->rwsem);
31
32 return NULL;
33}
34
35static void put_posix_clock(struct posix_clock *clk)
36{
37 up_read(&clk->rwsem);
38}
39
40static ssize_t posix_clock_read(struct file *fp, char __user *buf,
41 size_t count, loff_t *ppos)
42{
43 struct posix_clock_context *pccontext = fp->private_data;
44 struct posix_clock *clk = get_posix_clock(fp);
45 int err = -EINVAL;
46
47 if (!clk)
48 return -ENODEV;
49
50 if (clk->ops.read)
51 err = clk->ops.read(pccontext, fp->f_flags, buf, count);
52
53 put_posix_clock(clk);
54
55 return err;
56}
57
58static __poll_t posix_clock_poll(struct file *fp, poll_table *wait)
59{
60 struct posix_clock_context *pccontext = fp->private_data;
61 struct posix_clock *clk = get_posix_clock(fp);
62 __poll_t result = 0;
63
64 if (!clk)
65 return EPOLLERR;
66
67 if (clk->ops.poll)
68 result = clk->ops.poll(pccontext, fp, wait);
69
70 put_posix_clock(clk);
71
72 return result;
73}
74
75static long posix_clock_ioctl(struct file *fp,
76 unsigned int cmd, unsigned long arg)
77{
78 struct posix_clock_context *pccontext = fp->private_data;
79 struct posix_clock *clk = get_posix_clock(fp);
80 int err = -ENOTTY;
81
82 if (!clk)
83 return -ENODEV;
84
85 if (clk->ops.ioctl)
86 err = clk->ops.ioctl(pccontext, cmd, arg);
87
88 put_posix_clock(clk);
89
90 return err;
91}
92
93#ifdef CONFIG_COMPAT
94static long posix_clock_compat_ioctl(struct file *fp,
95 unsigned int cmd, unsigned long arg)
96{
97 struct posix_clock_context *pccontext = fp->private_data;
98 struct posix_clock *clk = get_posix_clock(fp);
99 int err = -ENOTTY;
100
101 if (!clk)
102 return -ENODEV;
103
104 if (clk->ops.ioctl)
105 err = clk->ops.ioctl(pccontext, cmd, arg);
106
107 put_posix_clock(clk);
108
109 return err;
110}
111#endif
112
113static int posix_clock_open(struct inode *inode, struct file *fp)
114{
115 int err;
116 struct posix_clock *clk =
117 container_of(inode->i_cdev, struct posix_clock, cdev);
118 struct posix_clock_context *pccontext;
119
120 down_read(&clk->rwsem);
121
122 if (clk->zombie) {
123 err = -ENODEV;
124 goto out;
125 }
126 pccontext = kzalloc(sizeof(*pccontext), GFP_KERNEL);
127 if (!pccontext) {
128 err = -ENOMEM;
129 goto out;
130 }
131 pccontext->clk = clk;
132 if (clk->ops.open) {
133 err = clk->ops.open(pccontext, fp->f_mode);
134 if (err) {
135 kfree(pccontext);
136 goto out;
137 }
138 }
139
140 fp->private_data = pccontext;
141 get_device(clk->dev);
142 err = 0;
143out:
144 up_read(&clk->rwsem);
145 return err;
146}
147
148static int posix_clock_release(struct inode *inode, struct file *fp)
149{
150 struct posix_clock_context *pccontext = fp->private_data;
151 struct posix_clock *clk;
152 int err = 0;
153
154 if (!pccontext)
155 return -ENODEV;
156 clk = pccontext->clk;
157
158 if (clk->ops.release)
159 err = clk->ops.release(pccontext);
160
161 put_device(clk->dev);
162
163 kfree(pccontext);
164 fp->private_data = NULL;
165
166 return err;
167}
168
169static const struct file_operations posix_clock_file_operations = {
170 .owner = THIS_MODULE,
171 .read = posix_clock_read,
172 .poll = posix_clock_poll,
173 .unlocked_ioctl = posix_clock_ioctl,
174 .open = posix_clock_open,
175 .release = posix_clock_release,
176#ifdef CONFIG_COMPAT
177 .compat_ioctl = posix_clock_compat_ioctl,
178#endif
179};
180
181int posix_clock_register(struct posix_clock *clk, struct device *dev)
182{
183 int err;
184
185 init_rwsem(&clk->rwsem);
186
187 cdev_init(&clk->cdev, &posix_clock_file_operations);
188 err = cdev_device_add(&clk->cdev, dev);
189 if (err) {
190 pr_err("%s unable to add device %d:%d\n",
191 dev_name(dev), MAJOR(dev->devt), MINOR(dev->devt));
192 return err;
193 }
194 clk->cdev.owner = clk->ops.owner;
195 clk->dev = dev;
196
197 return 0;
198}
199EXPORT_SYMBOL_GPL(posix_clock_register);
200
201void posix_clock_unregister(struct posix_clock *clk)
202{
203 cdev_device_del(&clk->cdev, clk->dev);
204
205 down_write(&clk->rwsem);
206 clk->zombie = true;
207 up_write(&clk->rwsem);
208
209 put_device(clk->dev);
210}
211EXPORT_SYMBOL_GPL(posix_clock_unregister);
212
213struct posix_clock_desc {
214 struct file *fp;
215 struct posix_clock *clk;
216};
217
218static int get_clock_desc(const clockid_t id, struct posix_clock_desc *cd)
219{
220 struct file *fp = fget(clockid_to_fd(id));
221 int err = -EINVAL;
222
223 if (!fp)
224 return err;
225
226 if (fp->f_op->open != posix_clock_open || !fp->private_data)
227 goto out;
228
229 cd->fp = fp;
230 cd->clk = get_posix_clock(fp);
231
232 err = cd->clk ? 0 : -ENODEV;
233out:
234 if (err)
235 fput(fp);
236 return err;
237}
238
239static void put_clock_desc(struct posix_clock_desc *cd)
240{
241 put_posix_clock(cd->clk);
242 fput(cd->fp);
243}
244
245static int pc_clock_adjtime(clockid_t id, struct __kernel_timex *tx)
246{
247 struct posix_clock_desc cd;
248 int err;
249
250 err = get_clock_desc(id, &cd);
251 if (err)
252 return err;
253
254 if ((cd.fp->f_mode & FMODE_WRITE) == 0) {
255 err = -EACCES;
256 goto out;
257 }
258
259 if (cd.clk->ops.clock_adjtime)
260 err = cd.clk->ops.clock_adjtime(cd.clk, tx);
261 else
262 err = -EOPNOTSUPP;
263out:
264 put_clock_desc(&cd);
265
266 return err;
267}
268
269static int pc_clock_gettime(clockid_t id, struct timespec64 *ts)
270{
271 struct posix_clock_desc cd;
272 int err;
273
274 err = get_clock_desc(id, &cd);
275 if (err)
276 return err;
277
278 if (cd.clk->ops.clock_gettime)
279 err = cd.clk->ops.clock_gettime(cd.clk, ts);
280 else
281 err = -EOPNOTSUPP;
282
283 put_clock_desc(&cd);
284
285 return err;
286}
287
288static int pc_clock_getres(clockid_t id, struct timespec64 *ts)
289{
290 struct posix_clock_desc cd;
291 int err;
292
293 err = get_clock_desc(id, &cd);
294 if (err)
295 return err;
296
297 if (cd.clk->ops.clock_getres)
298 err = cd.clk->ops.clock_getres(cd.clk, ts);
299 else
300 err = -EOPNOTSUPP;
301
302 put_clock_desc(&cd);
303
304 return err;
305}
306
307static int pc_clock_settime(clockid_t id, const struct timespec64 *ts)
308{
309 struct posix_clock_desc cd;
310 int err;
311
312 if (!timespec64_valid_strict(ts))
313 return -EINVAL;
314
315 err = get_clock_desc(id, &cd);
316 if (err)
317 return err;
318
319 if ((cd.fp->f_mode & FMODE_WRITE) == 0) {
320 err = -EACCES;
321 goto out;
322 }
323
324 if (cd.clk->ops.clock_settime)
325 err = cd.clk->ops.clock_settime(cd.clk, ts);
326 else
327 err = -EOPNOTSUPP;
328out:
329 put_clock_desc(&cd);
330
331 return err;
332}
333
334const struct k_clock clock_posix_dynamic = {
335 .clock_getres = pc_clock_getres,
336 .clock_set = pc_clock_settime,
337 .clock_get_timespec = pc_clock_gettime,
338 .clock_adj = pc_clock_adjtime,
339};