1
2
3
4
5
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
17static void delete_clock(struct kref *kref);
18
19
20
21
22static struct posix_clock *get_posix_clock(struct file *fp)
23{
24 struct posix_clock *clk = fp->private_data;
25
26 down_read(&clk->rwsem);
27
28 if (!clk->zombie)
29 return clk;
30
31 up_read(&clk->rwsem);
32
33 return NULL;
34}
35
36static void put_posix_clock(struct posix_clock *clk)
37{
38 up_read(&clk->rwsem);
39}
40
41static ssize_t posix_clock_read(struct file *fp, char __user *buf,
42 size_t count, loff_t *ppos)
43{
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(clk, 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 *clk = get_posix_clock(fp);
61 __poll_t result = 0;
62
63 if (!clk)
64 return EPOLLERR;
65
66 if (clk->ops.poll)
67 result = clk->ops.poll(clk, fp, wait);
68
69 put_posix_clock(clk);
70
71 return result;
72}
73
74static long posix_clock_ioctl(struct file *fp,
75 unsigned int cmd, unsigned long arg)
76{
77 struct posix_clock *clk = get_posix_clock(fp);
78 int err = -ENOTTY;
79
80 if (!clk)
81 return -ENODEV;
82
83 if (clk->ops.ioctl)
84 err = clk->ops.ioctl(clk, cmd, arg);
85
86 put_posix_clock(clk);
87
88 return err;
89}
90
91#ifdef CONFIG_COMPAT
92static long posix_clock_compat_ioctl(struct file *fp,
93 unsigned int cmd, unsigned long arg)
94{
95 struct posix_clock *clk = get_posix_clock(fp);
96 int err = -ENOTTY;
97
98 if (!clk)
99 return -ENODEV;
100
101 if (clk->ops.ioctl)
102 err = clk->ops.ioctl(clk, cmd, arg);
103
104 put_posix_clock(clk);
105
106 return err;
107}
108#endif
109
110static int posix_clock_open(struct inode *inode, struct file *fp)
111{
112 int err;
113 struct posix_clock *clk =
114 container_of(inode->i_cdev, struct posix_clock, cdev);
115
116 down_read(&clk->rwsem);
117
118 if (clk->zombie) {
119 err = -ENODEV;
120 goto out;
121 }
122 if (clk->ops.open)
123 err = clk->ops.open(clk, fp->f_mode);
124 else
125 err = 0;
126
127 if (!err) {
128 kref_get(&clk->kref);
129 fp->private_data = clk;
130 }
131out:
132 up_read(&clk->rwsem);
133 return err;
134}
135
136static int posix_clock_release(struct inode *inode, struct file *fp)
137{
138 struct posix_clock *clk = fp->private_data;
139 int err = 0;
140
141 if (clk->ops.release)
142 err = clk->ops.release(clk);
143
144 kref_put(&clk->kref, delete_clock);
145
146 fp->private_data = NULL;
147
148 return err;
149}
150
151static const struct file_operations posix_clock_file_operations = {
152 .owner = THIS_MODULE,
153 .llseek = no_llseek,
154 .read = posix_clock_read,
155 .poll = posix_clock_poll,
156 .unlocked_ioctl = posix_clock_ioctl,
157 .open = posix_clock_open,
158 .release = posix_clock_release,
159#ifdef CONFIG_COMPAT
160 .compat_ioctl = posix_clock_compat_ioctl,
161#endif
162};
163
164int posix_clock_register(struct posix_clock *clk, dev_t devid)
165{
166 int err;
167
168 kref_init(&clk->kref);
169 init_rwsem(&clk->rwsem);
170
171 cdev_init(&clk->cdev, &posix_clock_file_operations);
172 clk->cdev.owner = clk->ops.owner;
173 err = cdev_add(&clk->cdev, devid, 1);
174
175 return err;
176}
177EXPORT_SYMBOL_GPL(posix_clock_register);
178
179static void delete_clock(struct kref *kref)
180{
181 struct posix_clock *clk = container_of(kref, struct posix_clock, kref);
182
183 if (clk->release)
184 clk->release(clk);
185}
186
187void posix_clock_unregister(struct posix_clock *clk)
188{
189 cdev_del(&clk->cdev);
190
191 down_write(&clk->rwsem);
192 clk->zombie = true;
193 up_write(&clk->rwsem);
194
195 kref_put(&clk->kref, delete_clock);
196}
197EXPORT_SYMBOL_GPL(posix_clock_unregister);
198
199struct posix_clock_desc {
200 struct file *fp;
201 struct posix_clock *clk;
202};
203
204static int get_clock_desc(const clockid_t id, struct posix_clock_desc *cd)
205{
206 struct file *fp = fget(clockid_to_fd(id));
207 int err = -EINVAL;
208
209 if (!fp)
210 return err;
211
212 if (fp->f_op->open != posix_clock_open || !fp->private_data)
213 goto out;
214
215 cd->fp = fp;
216 cd->clk = get_posix_clock(fp);
217
218 err = cd->clk ? 0 : -ENODEV;
219out:
220 if (err)
221 fput(fp);
222 return err;
223}
224
225static void put_clock_desc(struct posix_clock_desc *cd)
226{
227 put_posix_clock(cd->clk);
228 fput(cd->fp);
229}
230
231static int pc_clock_adjtime(clockid_t id, struct __kernel_timex *tx)
232{
233 struct posix_clock_desc cd;
234 int err;
235
236 err = get_clock_desc(id, &cd);
237 if (err)
238 return err;
239
240 if ((cd.fp->f_mode & FMODE_WRITE) == 0) {
241 err = -EACCES;
242 goto out;
243 }
244
245 if (cd.clk->ops.clock_adjtime)
246 err = cd.clk->ops.clock_adjtime(cd.clk, tx);
247 else
248 err = -EOPNOTSUPP;
249out:
250 put_clock_desc(&cd);
251
252 return err;
253}
254
255static int pc_clock_gettime(clockid_t id, struct timespec64 *ts)
256{
257 struct posix_clock_desc cd;
258 int err;
259
260 err = get_clock_desc(id, &cd);
261 if (err)
262 return err;
263
264 if (cd.clk->ops.clock_gettime)
265 err = cd.clk->ops.clock_gettime(cd.clk, ts);
266 else
267 err = -EOPNOTSUPP;
268
269 put_clock_desc(&cd);
270
271 return err;
272}
273
274static int pc_clock_getres(clockid_t id, struct timespec64 *ts)
275{
276 struct posix_clock_desc cd;
277 int err;
278
279 err = get_clock_desc(id, &cd);
280 if (err)
281 return err;
282
283 if (cd.clk->ops.clock_getres)
284 err = cd.clk->ops.clock_getres(cd.clk, ts);
285 else
286 err = -EOPNOTSUPP;
287
288 put_clock_desc(&cd);
289
290 return err;
291}
292
293static int pc_clock_settime(clockid_t id, const struct timespec64 *ts)
294{
295 struct posix_clock_desc cd;
296 int err;
297
298 err = get_clock_desc(id, &cd);
299 if (err)
300 return err;
301
302 if ((cd.fp->f_mode & FMODE_WRITE) == 0) {
303 err = -EACCES;
304 goto out;
305 }
306
307 if (cd.clk->ops.clock_settime)
308 err = cd.clk->ops.clock_settime(cd.clk, ts);
309 else
310 err = -EOPNOTSUPP;
311out:
312 put_clock_desc(&cd);
313
314 return err;
315}
316
317const struct k_clock clock_posix_dynamic = {
318 .clock_getres = pc_clock_getres,
319 .clock_set = pc_clock_settime,
320 .clock_get = pc_clock_gettime,
321 .clock_adj = pc_clock_adjtime,
322};
323
