Commit | Line | Data |
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1d498196 MD |
1 | /* |
2 | * libringbuffer/shm.c | |
3 | * | |
e92f3e28 | 4 | * Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
1d498196 | 5 | * |
e92f3e28 MD |
6 | * This library is free software; you can redistribute it and/or |
7 | * modify it under the terms of the GNU Lesser General Public | |
8 | * License as published by the Free Software Foundation; only | |
9 | * version 2.1 of the License. | |
10 | * | |
11 | * This library 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 GNU | |
14 | * Lesser General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU Lesser General Public | |
17 | * License along with this library; if not, write to the Free Software | |
18 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
1d498196 MD |
19 | */ |
20 | ||
21 | #include "shm.h" | |
22 | #include <unistd.h> | |
23 | #include <fcntl.h> | |
24 | #include <sys/mman.h> | |
25 | #include <sys/stat.h> /* For mode constants */ | |
26 | #include <fcntl.h> /* For O_* constants */ | |
27 | #include <assert.h> | |
8da6cd6d MD |
28 | #include <stdio.h> |
29 | #include <signal.h> | |
30 | #include <dirent.h> | |
4318ae1b | 31 | #include <lttng/align.h> |
35897f8b | 32 | #include <helper.h> |
96e80018 | 33 | #include <limits.h> |
3a81f31d MD |
34 | #include <helper.h> |
35 | ||
36 | /* | |
37 | * Ensure we have the required amount of space available by writing 0 | |
38 | * into the entire buffer. Not doing so can trigger SIGBUS when going | |
39 | * beyond the available shm space. | |
40 | */ | |
41 | static | |
42 | int zero_file(int fd, size_t len) | |
43 | { | |
44 | ssize_t retlen; | |
45 | size_t written = 0; | |
46 | char *zeropage; | |
47 | long pagelen; | |
48 | int ret; | |
49 | ||
50 | pagelen = sysconf(_SC_PAGESIZE); | |
51 | if (pagelen < 0) | |
52 | return (int) pagelen; | |
53 | zeropage = calloc(pagelen, 1); | |
54 | if (!zeropage) | |
55 | return -ENOMEM; | |
56 | ||
57 | while (len > written) { | |
58 | do { | |
59 | retlen = write(fd, zeropage, | |
60 | min_t(size_t, pagelen, len - written)); | |
61 | } while (retlen == -1UL && errno == EINTR); | |
62 | if (retlen < 0) { | |
63 | ret = (int) retlen; | |
64 | goto error; | |
65 | } | |
66 | written += retlen; | |
67 | } | |
68 | ret = 0; | |
69 | error: | |
70 | free(zeropage); | |
71 | return ret; | |
72 | } | |
1d498196 MD |
73 | |
74 | struct shm_object_table *shm_object_table_create(size_t max_nb_obj) | |
75 | { | |
76 | struct shm_object_table *table; | |
77 | ||
78 | table = zmalloc(sizeof(struct shm_object_table) + | |
79 | max_nb_obj * sizeof(table->objects[0])); | |
74d48abe MD |
80 | if (!table) |
81 | return NULL; | |
1d498196 MD |
82 | table->size = max_nb_obj; |
83 | return table; | |
84 | } | |
85 | ||
74d81a6c MD |
86 | static |
87 | struct shm_object *_shm_object_table_alloc_shm(struct shm_object_table *table, | |
1d498196 MD |
88 | size_t memory_map_size) |
89 | { | |
5a61337d | 90 | int shmfd, waitfd[2], ret, i, sigblocked = 0; |
1d498196 MD |
91 | struct shm_object *obj; |
92 | char *memory_map; | |
dda4784f | 93 | char tmp_name[NAME_MAX] = "/ust-shm-tmp-XXXXXX"; |
8da6cd6d | 94 | sigset_t all_sigs, orig_sigs; |
1d498196 MD |
95 | |
96 | if (table->allocated_len >= table->size) | |
97 | return NULL; | |
7a9c21bd | 98 | obj = &table->objects[table->allocated_len]; |
1d498196 MD |
99 | |
100 | /* wait_fd: create pipe */ | |
101 | ret = pipe(waitfd); | |
102 | if (ret < 0) { | |
103 | PERROR("pipe"); | |
104 | goto error_pipe; | |
105 | } | |
106 | for (i = 0; i < 2; i++) { | |
107 | ret = fcntl(waitfd[i], F_SETFD, FD_CLOEXEC); | |
108 | if (ret < 0) { | |
109 | PERROR("fcntl"); | |
110 | goto error_fcntl; | |
111 | } | |
112 | } | |
5d61a504 MD |
113 | /* The write end of the pipe needs to be non-blocking */ |
114 | ret = fcntl(waitfd[1], F_SETFL, O_NONBLOCK); | |
115 | if (ret < 0) { | |
116 | PERROR("fcntl"); | |
117 | goto error_fcntl; | |
118 | } | |
7a9c21bd | 119 | memcpy(obj->wait_fd, waitfd, sizeof(waitfd)); |
1d498196 MD |
120 | |
121 | /* shm_fd: create shm */ | |
122 | ||
8da6cd6d MD |
123 | /* |
124 | * Theoretically, we could leak a shm if the application crashes | |
125 | * between open and unlink. Disable signals on this thread for | |
126 | * increased safety against this scenario. | |
127 | */ | |
128 | sigfillset(&all_sigs); | |
129 | ret = pthread_sigmask(SIG_BLOCK, &all_sigs, &orig_sigs); | |
130 | if (ret == -1) { | |
131 | PERROR("pthread_sigmask"); | |
132 | goto error_pthread_sigmask; | |
133 | } | |
5a61337d | 134 | sigblocked = 1; |
8da6cd6d | 135 | |
1d498196 MD |
136 | /* |
137 | * Allocate shm, and immediately unlink its shm oject, keeping | |
138 | * only the file descriptor as a reference to the object. If it | |
139 | * already exists (caused by short race window during which the | |
140 | * global object exists in a concurrent shm_open), simply retry. | |
141 | * We specifically do _not_ use the / at the beginning of the | |
142 | * pathname so that some OS implementations can keep it local to | |
143 | * the process (POSIX leaves this implementation-defined). | |
144 | */ | |
145 | do { | |
8da6cd6d MD |
146 | /* |
147 | * Using mktemp filename with O_CREAT | O_EXCL open | |
148 | * flags. | |
149 | */ | |
af21f781 | 150 | (void) mktemp(tmp_name); |
8da6cd6d MD |
151 | if (tmp_name[0] == '\0') { |
152 | PERROR("mktemp"); | |
153 | goto error_shm_open; | |
a8803897 | 154 | } |
8da6cd6d | 155 | shmfd = shm_open(tmp_name, |
1d498196 | 156 | O_CREAT | O_EXCL | O_RDWR, 0700); |
8da6cd6d | 157 | } while (shmfd < 0 && (errno == EEXIST || errno == EACCES)); |
1d498196 MD |
158 | if (shmfd < 0) { |
159 | PERROR("shm_open"); | |
160 | goto error_shm_open; | |
161 | } | |
8da6cd6d | 162 | ret = shm_unlink(tmp_name); |
a8803897 MD |
163 | if (ret < 0 && errno != ENOENT) { |
164 | PERROR("shm_unlink"); | |
165 | goto error_shm_release; | |
166 | } | |
5a61337d | 167 | sigblocked = 0; |
8da6cd6d MD |
168 | ret = pthread_sigmask(SIG_SETMASK, &orig_sigs, NULL); |
169 | if (ret == -1) { | |
170 | PERROR("pthread_sigmask"); | |
5a61337d | 171 | goto error_sigmask_release; |
8da6cd6d | 172 | } |
3a81f31d MD |
173 | ret = zero_file(shmfd, memory_map_size); |
174 | if (ret) { | |
175 | PERROR("zero_file"); | |
176 | goto error_zero_file; | |
177 | } | |
1d498196 MD |
178 | ret = ftruncate(shmfd, memory_map_size); |
179 | if (ret) { | |
180 | PERROR("ftruncate"); | |
181 | goto error_ftruncate; | |
182 | } | |
183 | obj->shm_fd = shmfd; | |
184 | ||
185 | /* memory_map: mmap */ | |
186 | memory_map = mmap(NULL, memory_map_size, PROT_READ | PROT_WRITE, | |
187 | MAP_SHARED, shmfd, 0); | |
188 | if (memory_map == MAP_FAILED) { | |
189 | PERROR("mmap"); | |
190 | goto error_mmap; | |
191 | } | |
74d81a6c | 192 | obj->type = SHM_OBJECT_SHM; |
1d498196 MD |
193 | obj->memory_map = memory_map; |
194 | obj->memory_map_size = memory_map_size; | |
195 | obj->allocated_len = 0; | |
dc613eb9 | 196 | obj->index = table->allocated_len++; |
7a9c21bd | 197 | |
1d498196 MD |
198 | return obj; |
199 | ||
200 | error_mmap: | |
201 | error_ftruncate: | |
a8803897 | 202 | error_shm_release: |
3a81f31d | 203 | error_zero_file: |
5a61337d | 204 | error_sigmask_release: |
1d498196 MD |
205 | ret = close(shmfd); |
206 | if (ret) { | |
207 | PERROR("close"); | |
208 | assert(0); | |
209 | } | |
210 | error_shm_open: | |
5a61337d MD |
211 | if (sigblocked) { |
212 | ret = pthread_sigmask(SIG_SETMASK, &orig_sigs, NULL); | |
213 | if (ret == -1) { | |
214 | PERROR("pthread_sigmask"); | |
215 | } | |
216 | } | |
8da6cd6d | 217 | error_pthread_sigmask: |
1d498196 MD |
218 | error_fcntl: |
219 | for (i = 0; i < 2; i++) { | |
220 | ret = close(waitfd[i]); | |
221 | if (ret) { | |
222 | PERROR("close"); | |
223 | assert(0); | |
224 | } | |
225 | } | |
226 | error_pipe: | |
1d498196 | 227 | return NULL; |
1d498196 MD |
228 | } |
229 | ||
74d81a6c MD |
230 | static |
231 | struct shm_object *_shm_object_table_alloc_mem(struct shm_object_table *table, | |
232 | size_t memory_map_size) | |
233 | { | |
234 | struct shm_object *obj; | |
235 | void *memory_map; | |
ff0f5728 | 236 | int waitfd[2], i, ret; |
74d81a6c MD |
237 | |
238 | if (table->allocated_len >= table->size) | |
239 | return NULL; | |
240 | obj = &table->objects[table->allocated_len]; | |
241 | ||
242 | memory_map = zmalloc(memory_map_size); | |
243 | if (!memory_map) | |
244 | goto alloc_error; | |
245 | ||
ff0f5728 MD |
246 | /* wait_fd: create pipe */ |
247 | ret = pipe(waitfd); | |
248 | if (ret < 0) { | |
249 | PERROR("pipe"); | |
250 | goto error_pipe; | |
251 | } | |
252 | for (i = 0; i < 2; i++) { | |
253 | ret = fcntl(waitfd[i], F_SETFD, FD_CLOEXEC); | |
254 | if (ret < 0) { | |
255 | PERROR("fcntl"); | |
256 | goto error_fcntl; | |
257 | } | |
258 | } | |
259 | /* The write end of the pipe needs to be non-blocking */ | |
260 | ret = fcntl(waitfd[1], F_SETFL, O_NONBLOCK); | |
261 | if (ret < 0) { | |
262 | PERROR("fcntl"); | |
263 | goto error_fcntl; | |
264 | } | |
265 | memcpy(obj->wait_fd, waitfd, sizeof(waitfd)); | |
266 | ||
267 | /* no shm_fd */ | |
74d81a6c MD |
268 | obj->shm_fd = -1; |
269 | ||
270 | obj->type = SHM_OBJECT_MEM; | |
271 | obj->memory_map = memory_map; | |
272 | obj->memory_map_size = memory_map_size; | |
273 | obj->allocated_len = 0; | |
274 | obj->index = table->allocated_len++; | |
275 | ||
276 | return obj; | |
277 | ||
ff0f5728 MD |
278 | error_fcntl: |
279 | for (i = 0; i < 2; i++) { | |
280 | ret = close(waitfd[i]); | |
281 | if (ret) { | |
282 | PERROR("close"); | |
283 | assert(0); | |
284 | } | |
285 | } | |
286 | error_pipe: | |
287 | free(memory_map); | |
74d81a6c MD |
288 | alloc_error: |
289 | return NULL; | |
290 | } | |
291 | ||
292 | struct shm_object *shm_object_table_alloc(struct shm_object_table *table, | |
293 | size_t memory_map_size, | |
294 | enum shm_object_type type) | |
295 | { | |
296 | switch (type) { | |
297 | case SHM_OBJECT_SHM: | |
298 | return _shm_object_table_alloc_shm(table, memory_map_size); | |
299 | case SHM_OBJECT_MEM: | |
300 | return _shm_object_table_alloc_mem(table, memory_map_size); | |
301 | default: | |
302 | assert(0); | |
303 | } | |
304 | return NULL; | |
305 | } | |
306 | ||
307 | struct shm_object *shm_object_table_append_shm(struct shm_object_table *table, | |
308 | int shm_fd, int wakeup_fd, uint32_t stream_nr, | |
309 | size_t memory_map_size) | |
193183fb MD |
310 | { |
311 | struct shm_object *obj; | |
312 | char *memory_map; | |
74d81a6c | 313 | int ret; |
193183fb MD |
314 | |
315 | if (table->allocated_len >= table->size) | |
316 | return NULL; | |
74d81a6c MD |
317 | /* streams _must_ be received in sequential order, else fail. */ |
318 | if (stream_nr + 1 != table->allocated_len) | |
319 | return NULL; | |
320 | ||
193183fb MD |
321 | obj = &table->objects[table->allocated_len]; |
322 | ||
74d81a6c MD |
323 | /* wait_fd: set write end of the pipe. */ |
324 | obj->wait_fd[0] = -1; /* read end is unset */ | |
325 | obj->wait_fd[1] = wakeup_fd; | |
193183fb MD |
326 | obj->shm_fd = shm_fd; |
327 | ||
74d81a6c MD |
328 | ret = fcntl(obj->wait_fd[1], F_SETFD, FD_CLOEXEC); |
329 | if (ret < 0) { | |
330 | PERROR("fcntl"); | |
331 | goto error_fcntl; | |
332 | } | |
333 | /* The write end of the pipe needs to be non-blocking */ | |
334 | ret = fcntl(obj->wait_fd[1], F_SETFL, O_NONBLOCK); | |
335 | if (ret < 0) { | |
336 | PERROR("fcntl"); | |
337 | goto error_fcntl; | |
338 | } | |
339 | ||
193183fb MD |
340 | /* memory_map: mmap */ |
341 | memory_map = mmap(NULL, memory_map_size, PROT_READ | PROT_WRITE, | |
342 | MAP_SHARED, shm_fd, 0); | |
343 | if (memory_map == MAP_FAILED) { | |
344 | PERROR("mmap"); | |
345 | goto error_mmap; | |
346 | } | |
74d81a6c | 347 | obj->type = SHM_OBJECT_SHM; |
193183fb MD |
348 | obj->memory_map = memory_map; |
349 | obj->memory_map_size = memory_map_size; | |
350 | obj->allocated_len = memory_map_size; | |
351 | obj->index = table->allocated_len++; | |
352 | ||
353 | return obj; | |
354 | ||
74d81a6c | 355 | error_fcntl: |
193183fb MD |
356 | error_mmap: |
357 | return NULL; | |
358 | } | |
359 | ||
74d81a6c MD |
360 | /* |
361 | * Passing ownership of mem to object. | |
362 | */ | |
363 | struct shm_object *shm_object_table_append_mem(struct shm_object_table *table, | |
ff0f5728 | 364 | void *mem, size_t memory_map_size, int wakeup_fd) |
74d81a6c MD |
365 | { |
366 | struct shm_object *obj; | |
ff0f5728 | 367 | int ret; |
74d81a6c MD |
368 | |
369 | if (table->allocated_len >= table->size) | |
370 | return NULL; | |
371 | obj = &table->objects[table->allocated_len]; | |
372 | ||
ff0f5728 MD |
373 | obj->wait_fd[0] = -1; /* read end is unset */ |
374 | obj->wait_fd[1] = wakeup_fd; | |
74d81a6c MD |
375 | obj->shm_fd = -1; |
376 | ||
ff0f5728 MD |
377 | ret = fcntl(obj->wait_fd[1], F_SETFD, FD_CLOEXEC); |
378 | if (ret < 0) { | |
379 | PERROR("fcntl"); | |
380 | goto error_fcntl; | |
381 | } | |
382 | /* The write end of the pipe needs to be non-blocking */ | |
383 | ret = fcntl(obj->wait_fd[1], F_SETFL, O_NONBLOCK); | |
384 | if (ret < 0) { | |
385 | PERROR("fcntl"); | |
386 | goto error_fcntl; | |
387 | } | |
388 | ||
74d81a6c MD |
389 | obj->type = SHM_OBJECT_MEM; |
390 | obj->memory_map = mem; | |
391 | obj->memory_map_size = memory_map_size; | |
392 | obj->allocated_len = memory_map_size; | |
393 | obj->index = table->allocated_len++; | |
394 | ||
395 | return obj; | |
ff0f5728 MD |
396 | |
397 | error_fcntl: | |
398 | return NULL; | |
74d81a6c MD |
399 | } |
400 | ||
1d498196 MD |
401 | static |
402 | void shmp_object_destroy(struct shm_object *obj) | |
403 | { | |
74d81a6c MD |
404 | switch (obj->type) { |
405 | case SHM_OBJECT_SHM: | |
406 | { | |
407 | int ret, i; | |
1d498196 | 408 | |
7a784989 MD |
409 | ret = munmap(obj->memory_map, obj->memory_map_size); |
410 | if (ret) { | |
411 | PERROR("umnmap"); | |
412 | assert(0); | |
413 | } | |
ef9ff354 MD |
414 | ret = close(obj->shm_fd); |
415 | if (ret) { | |
416 | PERROR("close"); | |
417 | assert(0); | |
418 | } | |
74d81a6c MD |
419 | for (i = 0; i < 2; i++) { |
420 | if (obj->wait_fd[i] < 0) | |
421 | continue; | |
422 | ret = close(obj->wait_fd[i]); | |
423 | if (ret) { | |
424 | PERROR("close"); | |
425 | assert(0); | |
426 | } | |
1d498196 | 427 | } |
74d81a6c MD |
428 | break; |
429 | } | |
430 | case SHM_OBJECT_MEM: | |
ff0f5728 MD |
431 | { |
432 | int ret, i; | |
433 | ||
434 | for (i = 0; i < 2; i++) { | |
435 | if (obj->wait_fd[i] < 0) | |
436 | continue; | |
437 | ret = close(obj->wait_fd[i]); | |
438 | if (ret) { | |
439 | PERROR("close"); | |
440 | assert(0); | |
441 | } | |
442 | } | |
74d81a6c MD |
443 | free(obj->memory_map); |
444 | break; | |
ff0f5728 | 445 | } |
74d81a6c MD |
446 | default: |
447 | assert(0); | |
1d498196 MD |
448 | } |
449 | } | |
450 | ||
451 | void shm_object_table_destroy(struct shm_object_table *table) | |
452 | { | |
453 | int i; | |
454 | ||
455 | for (i = 0; i < table->allocated_len; i++) | |
456 | shmp_object_destroy(&table->objects[i]); | |
457 | free(table); | |
458 | } | |
459 | ||
460 | /* | |
461 | * zalloc_shm - allocate memory within a shm object. | |
462 | * | |
463 | * Shared memory is already zeroed by shmget. | |
464 | * *NOT* multithread-safe (should be protected by mutex). | |
465 | * Returns a -1, -1 tuple on error. | |
466 | */ | |
467 | struct shm_ref zalloc_shm(struct shm_object *obj, size_t len) | |
468 | { | |
469 | struct shm_ref ref; | |
470 | struct shm_ref shm_ref_error = { -1, -1 }; | |
471 | ||
472 | if (obj->memory_map_size - obj->allocated_len < len) | |
473 | return shm_ref_error; | |
474 | ref.index = obj->index; | |
475 | ref.offset = obj->allocated_len; | |
476 | obj->allocated_len += len; | |
477 | return ref; | |
478 | } | |
479 | ||
480 | void align_shm(struct shm_object *obj, size_t align) | |
481 | { | |
482 | size_t offset_len = offset_align(obj->allocated_len, align); | |
483 | obj->allocated_len += offset_len; | |
484 | } |