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1 | /* |
2 | * libcounter/shm.c | |
3 | * | |
4 | * Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
5 | * | |
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 | |
19 | */ | |
20 | ||
21 | #define _LGPL_SOURCE | |
22 | #include <config.h> | |
23 | #include "shm.h" | |
24 | #include <unistd.h> | |
25 | #include <fcntl.h> | |
26 | #include <sys/mman.h> | |
27 | #include <sys/types.h> | |
28 | #include <sys/stat.h> /* For mode constants */ | |
29 | #include <fcntl.h> /* For O_* constants */ | |
30 | #include <assert.h> | |
31 | #include <stdio.h> | |
32 | #include <signal.h> | |
33 | #include <dirent.h> | |
34 | #include <lttng/align.h> | |
35 | #include <limits.h> | |
36 | #include <stdbool.h> | |
37 | #include <stdint.h> | |
38 | #ifdef HAVE_LIBNUMA | |
39 | #include <numa.h> | |
40 | #include <numaif.h> | |
41 | #endif | |
42 | #include <helper.h> | |
43 | #include <ust-fd.h> | |
44 | #include "../libringbuffer/mmap.h" | |
45 | ||
46 | /* | |
47 | * Ensure we have the required amount of space available by writing 0 | |
48 | * into the entire buffer. Not doing so can trigger SIGBUS when going | |
49 | * beyond the available shm space. | |
50 | */ | |
51 | static | |
52 | int zero_file(int fd, size_t len) | |
53 | { | |
54 | ssize_t retlen; | |
55 | size_t written = 0; | |
56 | char *zeropage; | |
57 | long pagelen; | |
58 | int ret; | |
59 | ||
60 | pagelen = sysconf(_SC_PAGESIZE); | |
61 | if (pagelen < 0) | |
62 | return (int) pagelen; | |
63 | zeropage = calloc(pagelen, 1); | |
64 | if (!zeropage) | |
65 | return -ENOMEM; | |
66 | ||
67 | while (len > written) { | |
68 | do { | |
69 | retlen = write(fd, zeropage, | |
70 | min_t(size_t, pagelen, len - written)); | |
71 | } while (retlen == -1UL && errno == EINTR); | |
72 | if (retlen < 0) { | |
73 | ret = (int) retlen; | |
74 | goto error; | |
75 | } | |
76 | written += retlen; | |
77 | } | |
78 | ret = 0; | |
79 | error: | |
80 | free(zeropage); | |
81 | return ret; | |
82 | } | |
83 | ||
84 | struct lttng_counter_shm_object_table *lttng_counter_shm_object_table_create(size_t max_nb_obj) | |
85 | { | |
86 | struct lttng_counter_shm_object_table *table; | |
87 | ||
88 | table = zmalloc(sizeof(struct lttng_counter_shm_object_table) + | |
89 | max_nb_obj * sizeof(table->objects[0])); | |
90 | if (!table) | |
91 | return NULL; | |
92 | table->size = max_nb_obj; | |
93 | return table; | |
94 | } | |
95 | ||
96 | static | |
97 | struct lttng_counter_shm_object *_lttng_counter_shm_object_table_alloc_shm(struct lttng_counter_shm_object_table *table, | |
98 | size_t memory_map_size, | |
99 | int cpu_fd) | |
100 | { | |
101 | int shmfd, ret; | |
102 | struct lttng_counter_shm_object *obj; | |
103 | char *memory_map; | |
104 | ||
105 | if (cpu_fd < 0) | |
106 | return NULL; | |
107 | if (table->allocated_len >= table->size) | |
108 | return NULL; | |
109 | obj = &table->objects[table->allocated_len]; | |
110 | ||
111 | /* create shm */ | |
112 | ||
113 | shmfd = cpu_fd; | |
114 | ret = zero_file(shmfd, memory_map_size); | |
115 | if (ret) { | |
116 | PERROR("zero_file"); | |
117 | goto error_zero_file; | |
118 | } | |
119 | ret = ftruncate(shmfd, memory_map_size); | |
120 | if (ret) { | |
121 | PERROR("ftruncate"); | |
122 | goto error_ftruncate; | |
123 | } | |
124 | /* | |
125 | * Also ensure the file metadata is synced with the storage by using | |
126 | * fsync(2). | |
127 | */ | |
128 | ret = fsync(shmfd); | |
129 | if (ret) { | |
130 | PERROR("fsync"); | |
131 | goto error_fsync; | |
132 | } | |
133 | obj->shm_fd_ownership = 0; | |
134 | obj->shm_fd = shmfd; | |
135 | ||
136 | /* memory_map: mmap */ | |
137 | memory_map = mmap(NULL, memory_map_size, PROT_READ | PROT_WRITE, | |
138 | MAP_SHARED | LTTNG_MAP_POPULATE, shmfd, 0); | |
139 | if (memory_map == MAP_FAILED) { | |
140 | PERROR("mmap"); | |
141 | goto error_mmap; | |
142 | } | |
143 | obj->type = LTTNG_COUNTER_SHM_OBJECT_SHM; | |
144 | obj->memory_map = memory_map; | |
145 | obj->memory_map_size = memory_map_size; | |
146 | obj->allocated_len = 0; | |
147 | obj->index = table->allocated_len++; | |
148 | ||
149 | return obj; | |
150 | ||
151 | error_mmap: | |
152 | error_fsync: | |
153 | error_ftruncate: | |
154 | error_zero_file: | |
155 | return NULL; | |
156 | } | |
157 | ||
158 | static | |
159 | struct lttng_counter_shm_object *_lttng_counter_shm_object_table_alloc_mem(struct lttng_counter_shm_object_table *table, | |
160 | size_t memory_map_size) | |
161 | { | |
162 | struct lttng_counter_shm_object *obj; | |
163 | void *memory_map; | |
164 | ||
165 | if (table->allocated_len >= table->size) | |
166 | return NULL; | |
167 | obj = &table->objects[table->allocated_len]; | |
168 | ||
169 | memory_map = zmalloc(memory_map_size); | |
170 | if (!memory_map) | |
171 | goto alloc_error; | |
172 | ||
173 | /* no shm_fd */ | |
174 | obj->shm_fd = -1; | |
175 | obj->shm_fd_ownership = 0; | |
176 | ||
177 | obj->type = LTTNG_COUNTER_SHM_OBJECT_MEM; | |
178 | obj->memory_map = memory_map; | |
179 | obj->memory_map_size = memory_map_size; | |
180 | obj->allocated_len = 0; | |
181 | obj->index = table->allocated_len++; | |
182 | ||
183 | return obj; | |
184 | ||
185 | alloc_error: | |
186 | return NULL; | |
187 | } | |
188 | ||
189 | /* | |
190 | * libnuma prints errors on the console even for numa_available(). | |
191 | * Work-around this limitation by using get_mempolicy() directly to | |
192 | * check whether the kernel supports mempolicy. | |
193 | */ | |
194 | #ifdef HAVE_LIBNUMA | |
195 | static bool lttng_is_numa_available(void) | |
196 | { | |
197 | int ret; | |
198 | ||
199 | ret = get_mempolicy(NULL, NULL, 0, NULL, 0); | |
200 | if (ret && errno == ENOSYS) { | |
201 | return false; | |
202 | } | |
203 | return numa_available() > 0; | |
204 | } | |
205 | #endif | |
206 | ||
207 | struct lttng_counter_shm_object *lttng_counter_shm_object_table_alloc(struct lttng_counter_shm_object_table *table, | |
208 | size_t memory_map_size, | |
209 | enum lttng_counter_shm_object_type type, | |
210 | int cpu_fd, | |
211 | int cpu) | |
212 | { | |
213 | struct lttng_counter_shm_object *shm_object; | |
214 | #ifdef HAVE_LIBNUMA | |
215 | int oldnode = 0, node; | |
216 | bool numa_avail; | |
217 | ||
218 | numa_avail = lttng_is_numa_available(); | |
219 | if (numa_avail) { | |
220 | oldnode = numa_preferred(); | |
221 | if (cpu >= 0) { | |
222 | node = numa_node_of_cpu(cpu); | |
223 | if (node >= 0) | |
224 | numa_set_preferred(node); | |
225 | } | |
226 | if (cpu < 0 || node < 0) | |
227 | numa_set_localalloc(); | |
228 | } | |
229 | #endif /* HAVE_LIBNUMA */ | |
230 | switch (type) { | |
231 | case LTTNG_COUNTER_SHM_OBJECT_SHM: | |
232 | shm_object = _lttng_counter_shm_object_table_alloc_shm(table, memory_map_size, | |
233 | cpu_fd); | |
234 | break; | |
235 | case LTTNG_COUNTER_SHM_OBJECT_MEM: | |
236 | shm_object = _lttng_counter_shm_object_table_alloc_mem(table, memory_map_size); | |
237 | break; | |
238 | default: | |
239 | assert(0); | |
240 | } | |
241 | #ifdef HAVE_LIBNUMA | |
242 | if (numa_avail) | |
243 | numa_set_preferred(oldnode); | |
244 | #endif /* HAVE_LIBNUMA */ | |
245 | return shm_object; | |
246 | } | |
247 | ||
248 | struct lttng_counter_shm_object *lttng_counter_shm_object_table_append_shm(struct lttng_counter_shm_object_table *table, | |
249 | int shm_fd, | |
250 | size_t memory_map_size) | |
251 | { | |
252 | struct lttng_counter_shm_object *obj; | |
253 | char *memory_map; | |
254 | ||
255 | if (table->allocated_len >= table->size) | |
256 | return NULL; | |
257 | ||
258 | obj = &table->objects[table->allocated_len]; | |
259 | ||
260 | obj->shm_fd = shm_fd; | |
261 | obj->shm_fd_ownership = 1; | |
262 | ||
263 | /* memory_map: mmap */ | |
264 | memory_map = mmap(NULL, memory_map_size, PROT_READ | PROT_WRITE, | |
265 | MAP_SHARED | LTTNG_MAP_POPULATE, shm_fd, 0); | |
266 | if (memory_map == MAP_FAILED) { | |
267 | PERROR("mmap"); | |
268 | goto error_mmap; | |
269 | } | |
270 | obj->type = LTTNG_COUNTER_SHM_OBJECT_SHM; | |
271 | obj->memory_map = memory_map; | |
272 | obj->memory_map_size = memory_map_size; | |
273 | obj->allocated_len = memory_map_size; | |
274 | obj->index = table->allocated_len++; | |
275 | ||
276 | return obj; | |
277 | ||
278 | error_mmap: | |
279 | return NULL; | |
280 | } | |
281 | ||
282 | /* | |
283 | * Passing ownership of mem to object. | |
284 | */ | |
285 | struct lttng_counter_shm_object *lttng_counter_shm_object_table_append_mem(struct lttng_counter_shm_object_table *table, | |
286 | void *mem, size_t memory_map_size) | |
287 | { | |
288 | struct lttng_counter_shm_object *obj; | |
289 | ||
290 | if (table->allocated_len >= table->size) | |
291 | return NULL; | |
292 | obj = &table->objects[table->allocated_len]; | |
293 | ||
294 | obj->shm_fd = -1; | |
295 | obj->shm_fd_ownership = 0; | |
296 | ||
297 | obj->type = LTTNG_COUNTER_SHM_OBJECT_MEM; | |
298 | obj->memory_map = mem; | |
299 | obj->memory_map_size = memory_map_size; | |
300 | obj->allocated_len = memory_map_size; | |
301 | obj->index = table->allocated_len++; | |
302 | ||
303 | return obj; | |
304 | ||
305 | return NULL; | |
306 | } | |
307 | ||
308 | static | |
309 | void lttng_counter_shmp_object_destroy(struct lttng_counter_shm_object *obj, int consumer) | |
310 | { | |
311 | switch (obj->type) { | |
312 | case LTTNG_COUNTER_SHM_OBJECT_SHM: | |
313 | { | |
314 | int ret; | |
315 | ||
316 | ret = munmap(obj->memory_map, obj->memory_map_size); | |
317 | if (ret) { | |
318 | PERROR("umnmap"); | |
319 | assert(0); | |
320 | } | |
321 | ||
322 | if (obj->shm_fd_ownership) { | |
323 | /* Delete FDs only if called from app (not consumer). */ | |
324 | if (!consumer) { | |
325 | lttng_ust_lock_fd_tracker(); | |
326 | ret = close(obj->shm_fd); | |
327 | if (!ret) { | |
328 | lttng_ust_delete_fd_from_tracker(obj->shm_fd); | |
329 | } else { | |
330 | PERROR("close"); | |
331 | assert(0); | |
332 | } | |
333 | lttng_ust_unlock_fd_tracker(); | |
334 | } else { | |
335 | ret = close(obj->shm_fd); | |
336 | if (ret) { | |
337 | PERROR("close"); | |
338 | assert(0); | |
339 | } | |
340 | } | |
341 | } | |
342 | break; | |
343 | } | |
344 | case LTTNG_COUNTER_SHM_OBJECT_MEM: | |
345 | { | |
346 | free(obj->memory_map); | |
347 | break; | |
348 | } | |
349 | default: | |
350 | assert(0); | |
351 | } | |
352 | } | |
353 | ||
354 | void lttng_counter_shm_object_table_destroy(struct lttng_counter_shm_object_table *table, int consumer) | |
355 | { | |
356 | int i; | |
357 | ||
358 | for (i = 0; i < table->allocated_len; i++) | |
359 | lttng_counter_shmp_object_destroy(&table->objects[i], consumer); | |
360 | free(table); | |
361 | } | |
362 | ||
363 | /* | |
364 | * lttng_counter_zalloc_shm - allocate memory within a shm object. | |
365 | * | |
366 | * Shared memory is already zeroed by shmget. | |
367 | * *NOT* multithread-safe (should be protected by mutex). | |
368 | * Returns a -1, -1 tuple on error. | |
369 | */ | |
370 | struct lttng_counter_shm_ref lttng_counter_zalloc_shm(struct lttng_counter_shm_object *obj, size_t len) | |
371 | { | |
372 | struct lttng_counter_shm_ref ref; | |
373 | struct lttng_counter_shm_ref shm_ref_error = { -1, -1 }; | |
374 | ||
375 | if (obj->memory_map_size - obj->allocated_len < len) | |
376 | return shm_ref_error; | |
377 | ref.index = obj->index; | |
378 | ref.offset = obj->allocated_len; | |
379 | obj->allocated_len += len; | |
380 | return ref; | |
381 | } | |
382 | ||
383 | void lttng_counter_align_shm(struct lttng_counter_shm_object *obj, size_t align) | |
384 | { | |
385 | size_t offset_len = offset_align(obj->allocated_len, align); | |
386 | obj->allocated_len += offset_len; | |
387 | } |