Commit | Line | Data |
---|---|---|
9f36eaed MJ |
1 | /* SPDX-License-Identifier: (GPL-2.0 OR LGPL-2.1) |
2 | * | |
f3bc08c5 MD |
3 | * ring_buffer_vfs.c |
4 | * | |
f3bc08c5 MD |
5 | * Ring Buffer VFS file operations. |
6 | * | |
886d51a3 | 7 | * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
f3bc08c5 MD |
8 | */ |
9 | ||
10 | #include <linux/module.h> | |
11 | #include <linux/fs.h> | |
12 | #include <linux/compat.h> | |
13 | ||
c075712b MD |
14 | #include <wrapper/ringbuffer/backend.h> |
15 | #include <wrapper/ringbuffer/frontend.h> | |
16 | #include <wrapper/ringbuffer/vfs.h> | |
17 | #include <wrapper/poll.h> | |
18 | #include <lttng-tracer.h> | |
f3bc08c5 MD |
19 | |
20 | static int put_ulong(unsigned long val, unsigned long arg) | |
21 | { | |
22 | return put_user(val, (unsigned long __user *)arg); | |
23 | } | |
24 | ||
25 | #ifdef CONFIG_COMPAT | |
26 | static int compat_put_ulong(compat_ulong_t val, unsigned long arg) | |
27 | { | |
28 | return put_user(val, (compat_ulong_t __user *)compat_ptr(arg)); | |
29 | } | |
30 | #endif | |
31 | ||
b3b8072b MD |
32 | /* |
33 | * This is not used by anonymous file descriptors. This code is left | |
34 | * there if we ever want to implement an inode with open() operation. | |
35 | */ | |
d83004aa JD |
36 | int lib_ring_buffer_open(struct inode *inode, struct file *file, |
37 | struct lib_ring_buffer *buf) | |
f3bc08c5 | 38 | { |
f3bc08c5 MD |
39 | int ret; |
40 | ||
733ce41d MD |
41 | if (!buf) |
42 | return -EINVAL; | |
43 | ||
f3bc08c5 MD |
44 | ret = lib_ring_buffer_open_read(buf); |
45 | if (ret) | |
46 | return ret; | |
47 | ||
f3bc08c5 MD |
48 | ret = nonseekable_open(inode, file); |
49 | if (ret) | |
50 | goto release_read; | |
51 | return 0; | |
52 | ||
53 | release_read: | |
54 | lib_ring_buffer_release_read(buf); | |
55 | return ret; | |
56 | } | |
d83004aa | 57 | EXPORT_SYMBOL_GPL(lib_ring_buffer_open); |
f3bc08c5 MD |
58 | |
59 | /** | |
d83004aa | 60 | * vfs_lib_ring_buffer_open - ring buffer open file operation |
f3bc08c5 MD |
61 | * @inode: opened inode |
62 | * @file: opened file | |
63 | * | |
d83004aa JD |
64 | * Open implementation. Makes sure only one open instance of a buffer is |
65 | * done at a given moment. | |
f3bc08c5 | 66 | */ |
d83004aa JD |
67 | static |
68 | int vfs_lib_ring_buffer_open(struct inode *inode, struct file *file) | |
f3bc08c5 | 69 | { |
d83004aa JD |
70 | struct lib_ring_buffer *buf = inode->i_private; |
71 | ||
72 | file->private_data = buf; | |
73 | return lib_ring_buffer_open(inode, file, buf); | |
74 | } | |
f3bc08c5 | 75 | |
d83004aa JD |
76 | int lib_ring_buffer_release(struct inode *inode, struct file *file, |
77 | struct lib_ring_buffer *buf) | |
78 | { | |
f3bc08c5 MD |
79 | lib_ring_buffer_release_read(buf); |
80 | ||
81 | return 0; | |
82 | } | |
d83004aa | 83 | EXPORT_SYMBOL_GPL(lib_ring_buffer_release); |
f3bc08c5 MD |
84 | |
85 | /** | |
d83004aa JD |
86 | * vfs_lib_ring_buffer_release - ring buffer release file operation |
87 | * @inode: opened inode | |
88 | * @file: opened file | |
f3bc08c5 | 89 | * |
d83004aa | 90 | * Release implementation. |
f3bc08c5 | 91 | */ |
d83004aa JD |
92 | static |
93 | int vfs_lib_ring_buffer_release(struct inode *inode, struct file *file) | |
94 | { | |
95 | struct lib_ring_buffer *buf = file->private_data; | |
96 | ||
97 | return lib_ring_buffer_release(inode, file, buf); | |
98 | } | |
99 | ||
100 | unsigned int lib_ring_buffer_poll(struct file *filp, poll_table *wait, | |
101 | struct lib_ring_buffer *buf) | |
f3bc08c5 MD |
102 | { |
103 | unsigned int mask = 0; | |
f3bc08c5 | 104 | struct channel *chan = buf->backend.chan; |
5a8fd222 | 105 | const struct lib_ring_buffer_config *config = &chan->backend.config; |
254ec7bc | 106 | int finalized, disabled; |
f3bc08c5 MD |
107 | |
108 | if (filp->f_mode & FMODE_READ) { | |
a33e44a6 | 109 | poll_wait_set_exclusive(wait); |
f3bc08c5 MD |
110 | poll_wait(filp, &buf->read_wait, wait); |
111 | ||
112 | finalized = lib_ring_buffer_is_finalized(config, buf); | |
254ec7bc MD |
113 | disabled = lib_ring_buffer_channel_is_disabled(chan); |
114 | ||
f3bc08c5 MD |
115 | /* |
116 | * lib_ring_buffer_is_finalized() contains a smp_rmb() ordering | |
117 | * finalized load before offsets loads. | |
118 | */ | |
119 | WARN_ON(atomic_long_read(&buf->active_readers) != 1); | |
120 | retry: | |
254ec7bc MD |
121 | if (disabled) |
122 | return POLLERR; | |
123 | ||
f3bc08c5 MD |
124 | if (subbuf_trunc(lib_ring_buffer_get_offset(config, buf), chan) |
125 | - subbuf_trunc(lib_ring_buffer_get_consumed(config, buf), chan) | |
126 | == 0) { | |
127 | if (finalized) | |
128 | return POLLHUP; | |
129 | else { | |
130 | /* | |
131 | * The memory barriers | |
132 | * __wait_event()/wake_up_interruptible() take | |
133 | * care of "raw_spin_is_locked" memory ordering. | |
134 | */ | |
135 | if (raw_spin_is_locked(&buf->raw_tick_nohz_spinlock)) | |
136 | goto retry; | |
137 | else | |
138 | return 0; | |
139 | } | |
140 | } else { | |
141 | if (subbuf_trunc(lib_ring_buffer_get_offset(config, buf), | |
142 | chan) | |
143 | - subbuf_trunc(lib_ring_buffer_get_consumed(config, buf), | |
144 | chan) | |
145 | >= chan->backend.buf_size) | |
146 | return POLLPRI | POLLRDBAND; | |
147 | else | |
148 | return POLLIN | POLLRDNORM; | |
149 | } | |
150 | } | |
151 | return mask; | |
152 | } | |
d83004aa | 153 | EXPORT_SYMBOL_GPL(lib_ring_buffer_poll); |
f3bc08c5 MD |
154 | |
155 | /** | |
d83004aa | 156 | * vfs_lib_ring_buffer_poll - ring buffer poll file operation |
f3bc08c5 | 157 | * @filp: the file |
d83004aa | 158 | * @wait: poll table |
f3bc08c5 | 159 | * |
d83004aa | 160 | * Poll implementation. |
f3bc08c5 | 161 | */ |
d83004aa JD |
162 | static |
163 | unsigned int vfs_lib_ring_buffer_poll(struct file *filp, poll_table *wait) | |
f3bc08c5 MD |
164 | { |
165 | struct lib_ring_buffer *buf = filp->private_data; | |
d83004aa JD |
166 | |
167 | return lib_ring_buffer_poll(filp, wait, buf); | |
168 | } | |
169 | ||
170 | long lib_ring_buffer_ioctl(struct file *filp, unsigned int cmd, | |
171 | unsigned long arg, struct lib_ring_buffer *buf) | |
172 | { | |
f3bc08c5 | 173 | struct channel *chan = buf->backend.chan; |
5a8fd222 | 174 | const struct lib_ring_buffer_config *config = &chan->backend.config; |
f3bc08c5 | 175 | |
254ec7bc MD |
176 | if (lib_ring_buffer_channel_is_disabled(chan)) |
177 | return -EIO; | |
178 | ||
f3bc08c5 MD |
179 | switch (cmd) { |
180 | case RING_BUFFER_SNAPSHOT: | |
181 | return lib_ring_buffer_snapshot(buf, &buf->cons_snapshot, | |
182 | &buf->prod_snapshot); | |
4dce5a48 JG |
183 | case RING_BUFFER_SNAPSHOT_SAMPLE_POSITIONS: |
184 | return lib_ring_buffer_snapshot_sample_positions(buf, | |
185 | &buf->cons_snapshot, &buf->prod_snapshot); | |
f3bc08c5 MD |
186 | case RING_BUFFER_SNAPSHOT_GET_CONSUMED: |
187 | return put_ulong(buf->cons_snapshot, arg); | |
188 | case RING_BUFFER_SNAPSHOT_GET_PRODUCED: | |
189 | return put_ulong(buf->prod_snapshot, arg); | |
190 | case RING_BUFFER_GET_SUBBUF: | |
191 | { | |
192 | unsigned long uconsume; | |
193 | long ret; | |
194 | ||
195 | ret = get_user(uconsume, (unsigned long __user *) arg); | |
196 | if (ret) | |
197 | return ret; /* will return -EFAULT */ | |
198 | ret = lib_ring_buffer_get_subbuf(buf, uconsume); | |
199 | if (!ret) { | |
200 | /* Set file position to zero at each successful "get" */ | |
201 | filp->f_pos = 0; | |
202 | } | |
203 | return ret; | |
204 | } | |
205 | case RING_BUFFER_PUT_SUBBUF: | |
206 | lib_ring_buffer_put_subbuf(buf); | |
207 | return 0; | |
208 | ||
209 | case RING_BUFFER_GET_NEXT_SUBBUF: | |
210 | { | |
211 | long ret; | |
212 | ||
213 | ret = lib_ring_buffer_get_next_subbuf(buf); | |
214 | if (!ret) { | |
215 | /* Set file position to zero at each successful "get" */ | |
216 | filp->f_pos = 0; | |
217 | } | |
218 | return ret; | |
219 | } | |
220 | case RING_BUFFER_PUT_NEXT_SUBBUF: | |
221 | lib_ring_buffer_put_next_subbuf(buf); | |
222 | return 0; | |
223 | case RING_BUFFER_GET_SUBBUF_SIZE: | |
224 | return put_ulong(lib_ring_buffer_get_read_data_size(config, buf), | |
225 | arg); | |
226 | case RING_BUFFER_GET_PADDED_SUBBUF_SIZE: | |
227 | { | |
228 | unsigned long size; | |
229 | ||
230 | size = lib_ring_buffer_get_read_data_size(config, buf); | |
231 | size = PAGE_ALIGN(size); | |
232 | return put_ulong(size, arg); | |
233 | } | |
234 | case RING_BUFFER_GET_MAX_SUBBUF_SIZE: | |
235 | return put_ulong(chan->backend.subbuf_size, arg); | |
236 | case RING_BUFFER_GET_MMAP_LEN: | |
237 | { | |
238 | unsigned long mmap_buf_len; | |
239 | ||
240 | if (config->output != RING_BUFFER_MMAP) | |
241 | return -EINVAL; | |
242 | mmap_buf_len = chan->backend.buf_size; | |
243 | if (chan->backend.extra_reader_sb) | |
244 | mmap_buf_len += chan->backend.subbuf_size; | |
245 | if (mmap_buf_len > INT_MAX) | |
246 | return -EFBIG; | |
247 | return put_ulong(mmap_buf_len, arg); | |
248 | } | |
249 | case RING_BUFFER_GET_MMAP_READ_OFFSET: | |
250 | { | |
251 | unsigned long sb_bindex; | |
252 | ||
253 | if (config->output != RING_BUFFER_MMAP) | |
254 | return -EINVAL; | |
255 | sb_bindex = subbuffer_id_get_index(config, | |
256 | buf->backend.buf_rsb.id); | |
257 | return put_ulong(buf->backend.array[sb_bindex]->mmap_offset, | |
258 | arg); | |
259 | } | |
5c055266 | 260 | case RING_BUFFER_FLUSH: |
5e391252 | 261 | lib_ring_buffer_switch_remote(buf); |
5c055266 | 262 | return 0; |
c6f05468 MD |
263 | case RING_BUFFER_FLUSH_EMPTY: |
264 | lib_ring_buffer_switch_remote_empty(buf); | |
265 | return 0; | |
c245d0d3 MD |
266 | case RING_BUFFER_CLEAR: |
267 | lib_ring_buffer_clear(buf); | |
268 | return 0; | |
f3bc08c5 MD |
269 | default: |
270 | return -ENOIOCTLCMD; | |
271 | } | |
272 | } | |
d83004aa JD |
273 | EXPORT_SYMBOL_GPL(lib_ring_buffer_ioctl); |
274 | ||
275 | /** | |
276 | * vfs_lib_ring_buffer_ioctl - control ring buffer reader synchronization | |
277 | * | |
278 | * @filp: the file | |
279 | * @cmd: the command | |
280 | * @arg: command arg | |
281 | * | |
282 | * This ioctl implements commands necessary for producer/consumer | |
283 | * and flight recorder reader interaction : | |
284 | * RING_BUFFER_GET_NEXT_SUBBUF | |
285 | * Get the next sub-buffer that can be read. It never blocks. | |
286 | * RING_BUFFER_PUT_NEXT_SUBBUF | |
287 | * Release the currently read sub-buffer. | |
288 | * RING_BUFFER_GET_SUBBUF_SIZE | |
289 | * returns the size of the current sub-buffer. | |
290 | * RING_BUFFER_GET_MAX_SUBBUF_SIZE | |
291 | * returns the maximum size for sub-buffers. | |
292 | * RING_BUFFER_GET_NUM_SUBBUF | |
293 | * returns the number of reader-visible sub-buffers in the per cpu | |
294 | * channel (for mmap). | |
295 | * RING_BUFFER_GET_MMAP_READ_OFFSET | |
296 | * returns the offset of the subbuffer belonging to the reader. | |
297 | * Should only be used for mmap clients. | |
298 | */ | |
299 | static | |
300 | long vfs_lib_ring_buffer_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) | |
301 | { | |
302 | struct lib_ring_buffer *buf = filp->private_data; | |
303 | ||
304 | return lib_ring_buffer_ioctl(filp, cmd, arg, buf); | |
305 | } | |
f3bc08c5 MD |
306 | |
307 | #ifdef CONFIG_COMPAT | |
308 | long lib_ring_buffer_compat_ioctl(struct file *filp, unsigned int cmd, | |
d83004aa | 309 | unsigned long arg, struct lib_ring_buffer *buf) |
f3bc08c5 | 310 | { |
f3bc08c5 | 311 | struct channel *chan = buf->backend.chan; |
5a8fd222 | 312 | const struct lib_ring_buffer_config *config = &chan->backend.config; |
254ec7bc MD |
313 | |
314 | if (lib_ring_buffer_channel_is_disabled(chan)) | |
315 | return -EIO; | |
f3bc08c5 MD |
316 | |
317 | switch (cmd) { | |
216f7feb | 318 | case RING_BUFFER_COMPAT_SNAPSHOT: |
f3bc08c5 MD |
319 | return lib_ring_buffer_snapshot(buf, &buf->cons_snapshot, |
320 | &buf->prod_snapshot); | |
4dce5a48 JG |
321 | case RING_BUFFER_COMPAT_SNAPSHOT_SAMPLE_POSITIONS: |
322 | return lib_ring_buffer_snapshot_sample_positions(buf, | |
323 | &buf->cons_snapshot, &buf->prod_snapshot); | |
216f7feb | 324 | case RING_BUFFER_COMPAT_SNAPSHOT_GET_CONSUMED: |
f3bc08c5 | 325 | return compat_put_ulong(buf->cons_snapshot, arg); |
216f7feb | 326 | case RING_BUFFER_COMPAT_SNAPSHOT_GET_PRODUCED: |
f3bc08c5 | 327 | return compat_put_ulong(buf->prod_snapshot, arg); |
216f7feb | 328 | case RING_BUFFER_COMPAT_GET_SUBBUF: |
f3bc08c5 MD |
329 | { |
330 | __u32 uconsume; | |
331 | unsigned long consume; | |
332 | long ret; | |
333 | ||
334 | ret = get_user(uconsume, (__u32 __user *) arg); | |
335 | if (ret) | |
336 | return ret; /* will return -EFAULT */ | |
337 | consume = buf->cons_snapshot; | |
338 | consume &= ~0xFFFFFFFFL; | |
339 | consume |= uconsume; | |
340 | ret = lib_ring_buffer_get_subbuf(buf, consume); | |
341 | if (!ret) { | |
342 | /* Set file position to zero at each successful "get" */ | |
343 | filp->f_pos = 0; | |
344 | } | |
345 | return ret; | |
346 | } | |
216f7feb | 347 | case RING_BUFFER_COMPAT_PUT_SUBBUF: |
f3bc08c5 MD |
348 | lib_ring_buffer_put_subbuf(buf); |
349 | return 0; | |
350 | ||
216f7feb | 351 | case RING_BUFFER_COMPAT_GET_NEXT_SUBBUF: |
f3bc08c5 MD |
352 | { |
353 | long ret; | |
354 | ||
355 | ret = lib_ring_buffer_get_next_subbuf(buf); | |
356 | if (!ret) { | |
357 | /* Set file position to zero at each successful "get" */ | |
358 | filp->f_pos = 0; | |
359 | } | |
360 | return ret; | |
361 | } | |
216f7feb | 362 | case RING_BUFFER_COMPAT_PUT_NEXT_SUBBUF: |
f3bc08c5 MD |
363 | lib_ring_buffer_put_next_subbuf(buf); |
364 | return 0; | |
216f7feb | 365 | case RING_BUFFER_COMPAT_GET_SUBBUF_SIZE: |
f3bc08c5 MD |
366 | { |
367 | unsigned long data_size; | |
368 | ||
369 | data_size = lib_ring_buffer_get_read_data_size(config, buf); | |
370 | if (data_size > UINT_MAX) | |
371 | return -EFBIG; | |
4343ec8e | 372 | return compat_put_ulong(data_size, arg); |
f3bc08c5 | 373 | } |
216f7feb | 374 | case RING_BUFFER_COMPAT_GET_PADDED_SUBBUF_SIZE: |
f3bc08c5 MD |
375 | { |
376 | unsigned long size; | |
377 | ||
378 | size = lib_ring_buffer_get_read_data_size(config, buf); | |
379 | size = PAGE_ALIGN(size); | |
380 | if (size > UINT_MAX) | |
381 | return -EFBIG; | |
4343ec8e | 382 | return compat_put_ulong(size, arg); |
f3bc08c5 | 383 | } |
216f7feb | 384 | case RING_BUFFER_COMPAT_GET_MAX_SUBBUF_SIZE: |
f3bc08c5 MD |
385 | if (chan->backend.subbuf_size > UINT_MAX) |
386 | return -EFBIG; | |
4343ec8e | 387 | return compat_put_ulong(chan->backend.subbuf_size, arg); |
216f7feb | 388 | case RING_BUFFER_COMPAT_GET_MMAP_LEN: |
f3bc08c5 MD |
389 | { |
390 | unsigned long mmap_buf_len; | |
391 | ||
392 | if (config->output != RING_BUFFER_MMAP) | |
393 | return -EINVAL; | |
394 | mmap_buf_len = chan->backend.buf_size; | |
395 | if (chan->backend.extra_reader_sb) | |
396 | mmap_buf_len += chan->backend.subbuf_size; | |
397 | if (mmap_buf_len > UINT_MAX) | |
398 | return -EFBIG; | |
4343ec8e | 399 | return compat_put_ulong(mmap_buf_len, arg); |
f3bc08c5 | 400 | } |
216f7feb | 401 | case RING_BUFFER_COMPAT_GET_MMAP_READ_OFFSET: |
f3bc08c5 MD |
402 | { |
403 | unsigned long sb_bindex, read_offset; | |
404 | ||
405 | if (config->output != RING_BUFFER_MMAP) | |
406 | return -EINVAL; | |
407 | sb_bindex = subbuffer_id_get_index(config, | |
408 | buf->backend.buf_rsb.id); | |
409 | read_offset = buf->backend.array[sb_bindex]->mmap_offset; | |
410 | if (read_offset > UINT_MAX) | |
411 | return -EINVAL; | |
4343ec8e | 412 | return compat_put_ulong(read_offset, arg); |
f3bc08c5 | 413 | } |
216f7feb | 414 | case RING_BUFFER_COMPAT_FLUSH: |
5e391252 | 415 | lib_ring_buffer_switch_remote(buf); |
5c055266 | 416 | return 0; |
c6f05468 MD |
417 | case RING_BUFFER_COMPAT_FLUSH_EMPTY: |
418 | lib_ring_buffer_switch_remote_empty(buf); | |
419 | return 0; | |
c245d0d3 MD |
420 | case RING_BUFFER_COMPAT_CLEAR: |
421 | lib_ring_buffer_clear(buf); | |
422 | return 0; | |
f3bc08c5 MD |
423 | default: |
424 | return -ENOIOCTLCMD; | |
425 | } | |
426 | } | |
d83004aa JD |
427 | EXPORT_SYMBOL_GPL(lib_ring_buffer_compat_ioctl); |
428 | ||
429 | static | |
430 | long vfs_lib_ring_buffer_compat_ioctl(struct file *filp, unsigned int cmd, | |
431 | unsigned long arg) | |
432 | { | |
433 | struct lib_ring_buffer *buf = filp->private_data; | |
434 | ||
435 | return lib_ring_buffer_compat_ioctl(filp, cmd, arg, buf); | |
436 | } | |
f3bc08c5 MD |
437 | #endif |
438 | ||
439 | const struct file_operations lib_ring_buffer_file_operations = { | |
a33c9927 | 440 | .owner = THIS_MODULE, |
d83004aa JD |
441 | .open = vfs_lib_ring_buffer_open, |
442 | .release = vfs_lib_ring_buffer_release, | |
443 | .poll = vfs_lib_ring_buffer_poll, | |
444 | .splice_read = vfs_lib_ring_buffer_splice_read, | |
445 | .mmap = vfs_lib_ring_buffer_mmap, | |
446 | .unlocked_ioctl = vfs_lib_ring_buffer_ioctl, | |
447 | .llseek = vfs_lib_ring_buffer_no_llseek, | |
f3bc08c5 | 448 | #ifdef CONFIG_COMPAT |
d83004aa | 449 | .compat_ioctl = vfs_lib_ring_buffer_compat_ioctl, |
f3bc08c5 MD |
450 | #endif |
451 | }; | |
452 | EXPORT_SYMBOL_GPL(lib_ring_buffer_file_operations); | |
453 | ||
454 | MODULE_LICENSE("GPL and additional rights"); | |
1c124020 MJ |
455 | MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>"); |
456 | MODULE_DESCRIPTION("LTTng ring buffer library"); | |
13ab8b0a MD |
457 | MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "." |
458 | __stringify(LTTNG_MODULES_MINOR_VERSION) "." | |
459 | __stringify(LTTNG_MODULES_PATCHLEVEL_VERSION) | |
460 | LTTNG_MODULES_EXTRAVERSION); |