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5eb91c98 DG |
1 | /* |
2 | * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca> | |
3 | * | |
d14d33bf AM |
4 | * This program is free software; you can redistribute it and/or modify |
5 | * it under the terms of the GNU General Public License, version 2 only, | |
6 | * as published by the Free Software Foundation. | |
5eb91c98 DG |
7 | * |
8 | * This program is distributed in the hope that it will be useful, but WITHOUT | |
9 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
10 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
11 | * more details. | |
12 | * | |
d14d33bf AM |
13 | * You should have received a copy of the GNU General Public License along |
14 | * with this program; if not, write to the Free Software Foundation, Inc., | |
15 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. | |
5eb91c98 DG |
16 | */ |
17 | ||
5bbf8b1b | 18 | #define _GNU_SOURCE |
d21b0d71 | 19 | #include <assert.h> |
5eb91c98 DG |
20 | #include <stdlib.h> |
21 | #include <sys/resource.h> | |
22 | #include <sys/time.h> | |
23 | ||
990570ed | 24 | #include <common/defaults.h> |
db758600 | 25 | #include <common/error.h> |
cfa9a5a2 DG |
26 | #include <common/macros.h> |
27 | #include <common/utils.h> | |
5eb91c98 DG |
28 | |
29 | #include "poll.h" | |
30 | ||
31 | unsigned int poll_max_size; | |
32 | ||
d21b0d71 DG |
33 | /* |
34 | * Resize the epoll events structure of the new size. | |
35 | * | |
36 | * Return 0 on success or else -1 with the current events pointer untouched. | |
37 | */ | |
38 | static int resize_poll_event(struct compat_poll_event_array *array, | |
39 | uint32_t new_size) | |
40 | { | |
41 | struct pollfd *ptr; | |
42 | ||
43 | assert(array); | |
44 | ||
ac018a8b DG |
45 | /* Refuse to resize the array more than the max size. */ |
46 | if (new_size > poll_max_size) { | |
47 | goto error; | |
48 | } | |
49 | ||
d21b0d71 DG |
50 | ptr = realloc(array->events, new_size * sizeof(*ptr)); |
51 | if (ptr == NULL) { | |
52 | PERROR("realloc epoll add"); | |
53 | goto error; | |
54 | } | |
55 | array->events = ptr; | |
56 | array->alloc_size = new_size; | |
57 | ||
58 | return 0; | |
59 | ||
60 | error: | |
61 | return -1; | |
62 | } | |
63 | ||
64 | /* | |
65 | * Update events with the current events object. | |
66 | */ | |
67 | static int update_current_events(struct lttng_poll_event *events) | |
68 | { | |
69 | int ret; | |
70 | struct compat_poll_event_array *current, *wait; | |
71 | ||
72 | assert(events); | |
73 | ||
74 | current = &events->current; | |
75 | wait = &events->wait; | |
76 | ||
77 | wait->nb_fd = current->nb_fd; | |
78 | if (events->need_realloc) { | |
79 | ret = resize_poll_event(wait, current->alloc_size); | |
80 | if (ret < 0) { | |
81 | goto error; | |
82 | } | |
83 | } | |
84 | memcpy(wait->events, current->events, | |
85 | current->nb_fd * sizeof(*current->events)); | |
86 | ||
87 | /* Update is done and realloc as well. */ | |
88 | events->need_update = 0; | |
89 | events->need_realloc = 0; | |
90 | ||
91 | return 0; | |
92 | ||
93 | error: | |
94 | return -1; | |
95 | } | |
96 | ||
5eb91c98 DG |
97 | /* |
98 | * Create pollfd data structure. | |
99 | */ | |
100 | int compat_poll_create(struct lttng_poll_event *events, int size) | |
101 | { | |
d21b0d71 DG |
102 | struct compat_poll_event_array *current, *wait; |
103 | ||
5eb91c98 DG |
104 | if (events == NULL || size <= 0) { |
105 | ERR("Wrong arguments for poll create"); | |
106 | goto error; | |
107 | } | |
108 | ||
109 | /* Don't bust the limit here */ | |
110 | if (size > poll_max_size) { | |
111 | size = poll_max_size; | |
112 | } | |
113 | ||
d21b0d71 DG |
114 | /* Reset everything before begining the allocation. */ |
115 | memset(events, 0, sizeof(struct lttng_poll_event)); | |
116 | ||
117 | /* Ease our life a bit. */ | |
118 | current = &events->current; | |
119 | wait = &events->wait; | |
120 | ||
5eb91c98 | 121 | /* This *must* be freed by using lttng_poll_free() */ |
d21b0d71 DG |
122 | wait->events = zmalloc(size * sizeof(struct pollfd)); |
123 | if (wait->events == NULL) { | |
ba7f0ae5 | 124 | perror("zmalloc struct pollfd"); |
5eb91c98 DG |
125 | goto error; |
126 | } | |
127 | ||
d21b0d71 DG |
128 | wait->alloc_size = wait->init_size = size; |
129 | ||
130 | current->events = zmalloc(size * sizeof(struct pollfd)); | |
131 | if (current->events == NULL) { | |
132 | perror("zmalloc struct current pollfd"); | |
133 | goto error; | |
134 | } | |
135 | ||
136 | current->alloc_size = current->init_size = size; | |
5eb91c98 DG |
137 | |
138 | return 0; | |
139 | ||
140 | error: | |
141 | return -1; | |
142 | } | |
143 | ||
144 | /* | |
145 | * Add fd to pollfd data structure with requested events. | |
146 | */ | |
147 | int compat_poll_add(struct lttng_poll_event *events, int fd, | |
148 | uint32_t req_events) | |
149 | { | |
d21b0d71 DG |
150 | int new_size, ret, i; |
151 | struct compat_poll_event_array *current; | |
5eb91c98 | 152 | |
d21b0d71 | 153 | if (events == NULL || events->current.events == NULL || fd < 0) { |
5eb91c98 DG |
154 | ERR("Bad compat poll add arguments"); |
155 | goto error; | |
156 | } | |
157 | ||
d21b0d71 DG |
158 | /* Ease our life a bit. */ |
159 | current = &events->current; | |
160 | ||
161 | /* Check if fd we are trying to add is already there. */ | |
162 | for (i = 0; i < current->nb_fd; i++) { | |
163 | /* Don't put back the fd we want to delete */ | |
164 | if (current->events[i].fd == fd) { | |
165 | errno = EEXIST; | |
5eb91c98 DG |
166 | goto error; |
167 | } | |
5eb91c98 DG |
168 | } |
169 | ||
d21b0d71 DG |
170 | /* Check for a needed resize of the array. */ |
171 | if (current->nb_fd > current->alloc_size) { | |
172 | /* Expand it by a power of two of the current size. */ | |
cfa9a5a2 DG |
173 | new_size = max_t(int, |
174 | 1U << utils_get_count_order_u32(current->nb_fd), | |
175 | current->alloc_size << 1UL); | |
d21b0d71 DG |
176 | ret = resize_poll_event(current, new_size); |
177 | if (ret < 0) { | |
178 | goto error; | |
179 | } | |
180 | events->need_realloc = 1; | |
181 | } | |
5eb91c98 | 182 | |
d21b0d71 DG |
183 | current->events[current->nb_fd].fd = fd; |
184 | current->events[current->nb_fd].events = req_events; | |
185 | current->nb_fd++; | |
186 | events->need_update = 1; | |
187 | ||
188 | DBG("fd %d of %d added to pollfd", fd, current->nb_fd); | |
5eb91c98 DG |
189 | |
190 | return 0; | |
191 | ||
192 | error: | |
193 | return -1; | |
194 | } | |
195 | ||
196 | /* | |
197 | * Remove a fd from the pollfd structure. | |
198 | */ | |
199 | int compat_poll_del(struct lttng_poll_event *events, int fd) | |
200 | { | |
d21b0d71 DG |
201 | int new_size, i, count = 0, ret; |
202 | struct compat_poll_event_array *current; | |
5eb91c98 | 203 | |
d21b0d71 | 204 | if (events == NULL || events->current.events == NULL || fd < 0) { |
5eb91c98 DG |
205 | ERR("Wrong arguments for poll del"); |
206 | goto error; | |
207 | } | |
208 | ||
d21b0d71 DG |
209 | /* Ease our life a bit. */ |
210 | current = &events->current; | |
5eb91c98 | 211 | |
d21b0d71 DG |
212 | /* Check if we need to shrink it down. */ |
213 | if ((current->nb_fd << 1UL) <= current->alloc_size && | |
214 | current->nb_fd >= current->init_size) { | |
215 | /* | |
216 | * Shrink if nb_fd multiplied by two is <= than the actual size and we | |
217 | * are above the initial size. | |
218 | */ | |
cfa9a5a2 DG |
219 | new_size = max_t(int, |
220 | utils_get_count_order_u32(current->nb_fd) >> 1U, | |
221 | current->alloc_size >> 1U); | |
d21b0d71 DG |
222 | ret = resize_poll_event(current, new_size); |
223 | if (ret < 0) { | |
224 | goto error; | |
225 | } | |
226 | events->need_realloc = 1; | |
5eb91c98 DG |
227 | } |
228 | ||
d21b0d71 | 229 | for (i = 0; i < current->nb_fd; i++) { |
5eb91c98 | 230 | /* Don't put back the fd we want to delete */ |
d21b0d71 DG |
231 | if (current->events[i].fd != fd) { |
232 | current->events[count].fd = current->events[i].fd; | |
233 | current->events[count].events = current->events[i].events; | |
5eb91c98 DG |
234 | count++; |
235 | } | |
236 | } | |
237 | ||
d21b0d71 DG |
238 | current->nb_fd--; |
239 | events->need_update = 1; | |
5eb91c98 DG |
240 | |
241 | return 0; | |
242 | ||
243 | error: | |
244 | return -1; | |
245 | } | |
246 | ||
247 | /* | |
248 | * Wait on poll() with timeout. Blocking call. | |
249 | */ | |
250 | int compat_poll_wait(struct lttng_poll_event *events, int timeout) | |
251 | { | |
252 | int ret; | |
253 | ||
d21b0d71 | 254 | if (events == NULL || events->current.events == NULL) { |
5eb91c98 DG |
255 | ERR("poll wait arguments error"); |
256 | goto error; | |
257 | } | |
258 | ||
d21b0d71 DG |
259 | if (events->current.nb_fd == 0) { |
260 | /* Return an invalid error to be consistent with epoll. */ | |
261 | errno = EINVAL; | |
262 | goto error; | |
263 | } | |
264 | ||
265 | if (events->need_update) { | |
266 | ret = update_current_events(events); | |
267 | if (ret < 0) { | |
268 | errno = ENOMEM; | |
269 | goto error; | |
270 | } | |
271 | } | |
272 | ||
273 | ret = poll(events->wait.events, events->wait.nb_fd, timeout); | |
5eb91c98 DG |
274 | if (ret < 0) { |
275 | /* At this point, every error is fatal */ | |
276 | perror("poll wait"); | |
277 | goto error; | |
278 | } | |
279 | ||
9ddba525 DG |
280 | /* |
281 | * poll() should always iterate on all FDs since we handle the pollset in | |
282 | * user space and after poll returns, we have to try every fd for a match. | |
283 | */ | |
d21b0d71 | 284 | return events->wait.nb_fd; |
5eb91c98 DG |
285 | |
286 | error: | |
287 | return -1; | |
288 | } | |
289 | ||
290 | /* | |
291 | * Setup poll set maximum size. | |
292 | */ | |
293 | void compat_poll_set_max_size(void) | |
294 | { | |
295 | int ret; | |
296 | struct rlimit lim; | |
297 | ||
298 | /* Default value */ | |
990570ed | 299 | poll_max_size = DEFAULT_POLL_SIZE; |
5eb91c98 DG |
300 | |
301 | ret = getrlimit(RLIMIT_NOFILE, &lim); | |
302 | if (ret < 0) { | |
303 | perror("getrlimit poll RLIMIT_NOFILE"); | |
304 | return; | |
305 | } | |
306 | ||
307 | poll_max_size = lim.rlim_cur; | |
d21b0d71 | 308 | if (poll_max_size == 0) { |
5eb91c98 | 309 | /* Extra precaution */ |
990570ed | 310 | poll_max_size = DEFAULT_POLL_SIZE; |
5eb91c98 DG |
311 | } |
312 | ||
313 | DBG("poll set max size set to %u", poll_max_size); | |
314 | } |