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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> |
5eb91c98 DG |
26 | |
27 | #include "poll.h" | |
28 | ||
29 | unsigned int poll_max_size; | |
30 | ||
d21b0d71 DG |
31 | /* |
32 | * Resize the epoll events structure of the new size. | |
33 | * | |
34 | * Return 0 on success or else -1 with the current events pointer untouched. | |
35 | */ | |
36 | static int resize_poll_event(struct compat_poll_event_array *array, | |
37 | uint32_t new_size) | |
38 | { | |
39 | struct pollfd *ptr; | |
40 | ||
41 | assert(array); | |
42 | ||
43 | ptr = realloc(array->events, new_size * sizeof(*ptr)); | |
44 | if (ptr == NULL) { | |
45 | PERROR("realloc epoll add"); | |
46 | goto error; | |
47 | } | |
48 | array->events = ptr; | |
49 | array->alloc_size = new_size; | |
50 | ||
51 | return 0; | |
52 | ||
53 | error: | |
54 | return -1; | |
55 | } | |
56 | ||
57 | /* | |
58 | * Update events with the current events object. | |
59 | */ | |
60 | static int update_current_events(struct lttng_poll_event *events) | |
61 | { | |
62 | int ret; | |
63 | struct compat_poll_event_array *current, *wait; | |
64 | ||
65 | assert(events); | |
66 | ||
67 | current = &events->current; | |
68 | wait = &events->wait; | |
69 | ||
70 | wait->nb_fd = current->nb_fd; | |
71 | if (events->need_realloc) { | |
72 | ret = resize_poll_event(wait, current->alloc_size); | |
73 | if (ret < 0) { | |
74 | goto error; | |
75 | } | |
76 | } | |
77 | memcpy(wait->events, current->events, | |
78 | current->nb_fd * sizeof(*current->events)); | |
79 | ||
80 | /* Update is done and realloc as well. */ | |
81 | events->need_update = 0; | |
82 | events->need_realloc = 0; | |
83 | ||
84 | return 0; | |
85 | ||
86 | error: | |
87 | return -1; | |
88 | } | |
89 | ||
5eb91c98 DG |
90 | /* |
91 | * Create pollfd data structure. | |
92 | */ | |
93 | int compat_poll_create(struct lttng_poll_event *events, int size) | |
94 | { | |
d21b0d71 DG |
95 | struct compat_poll_event_array *current, *wait; |
96 | ||
5eb91c98 DG |
97 | if (events == NULL || size <= 0) { |
98 | ERR("Wrong arguments for poll create"); | |
99 | goto error; | |
100 | } | |
101 | ||
102 | /* Don't bust the limit here */ | |
103 | if (size > poll_max_size) { | |
104 | size = poll_max_size; | |
105 | } | |
106 | ||
d21b0d71 DG |
107 | /* Reset everything before begining the allocation. */ |
108 | memset(events, 0, sizeof(struct lttng_poll_event)); | |
109 | ||
110 | /* Ease our life a bit. */ | |
111 | current = &events->current; | |
112 | wait = &events->wait; | |
113 | ||
5eb91c98 | 114 | /* This *must* be freed by using lttng_poll_free() */ |
d21b0d71 DG |
115 | wait->events = zmalloc(size * sizeof(struct pollfd)); |
116 | if (wait->events == NULL) { | |
ba7f0ae5 | 117 | perror("zmalloc struct pollfd"); |
5eb91c98 DG |
118 | goto error; |
119 | } | |
120 | ||
d21b0d71 DG |
121 | wait->alloc_size = wait->init_size = size; |
122 | ||
123 | current->events = zmalloc(size * sizeof(struct pollfd)); | |
124 | if (current->events == NULL) { | |
125 | perror("zmalloc struct current pollfd"); | |
126 | goto error; | |
127 | } | |
128 | ||
129 | current->alloc_size = current->init_size = size; | |
5eb91c98 DG |
130 | |
131 | return 0; | |
132 | ||
133 | error: | |
134 | return -1; | |
135 | } | |
136 | ||
137 | /* | |
138 | * Add fd to pollfd data structure with requested events. | |
139 | */ | |
140 | int compat_poll_add(struct lttng_poll_event *events, int fd, | |
141 | uint32_t req_events) | |
142 | { | |
d21b0d71 DG |
143 | int new_size, ret, i; |
144 | struct compat_poll_event_array *current; | |
5eb91c98 | 145 | |
d21b0d71 | 146 | if (events == NULL || events->current.events == NULL || fd < 0) { |
5eb91c98 DG |
147 | ERR("Bad compat poll add arguments"); |
148 | goto error; | |
149 | } | |
150 | ||
d21b0d71 DG |
151 | /* Ease our life a bit. */ |
152 | current = &events->current; | |
153 | ||
154 | /* Check if fd we are trying to add is already there. */ | |
155 | for (i = 0; i < current->nb_fd; i++) { | |
156 | /* Don't put back the fd we want to delete */ | |
157 | if (current->events[i].fd == fd) { | |
158 | errno = EEXIST; | |
5eb91c98 DG |
159 | goto error; |
160 | } | |
5eb91c98 DG |
161 | } |
162 | ||
d21b0d71 DG |
163 | /* Check for a needed resize of the array. */ |
164 | if (current->nb_fd > current->alloc_size) { | |
165 | /* Expand it by a power of two of the current size. */ | |
166 | new_size = current->alloc_size << 1UL; | |
167 | ret = resize_poll_event(current, new_size); | |
168 | if (ret < 0) { | |
169 | goto error; | |
170 | } | |
171 | events->need_realloc = 1; | |
172 | } | |
5eb91c98 | 173 | |
d21b0d71 DG |
174 | current->events[current->nb_fd].fd = fd; |
175 | current->events[current->nb_fd].events = req_events; | |
176 | current->nb_fd++; | |
177 | events->need_update = 1; | |
178 | ||
179 | DBG("fd %d of %d added to pollfd", fd, current->nb_fd); | |
5eb91c98 DG |
180 | |
181 | return 0; | |
182 | ||
183 | error: | |
184 | return -1; | |
185 | } | |
186 | ||
187 | /* | |
188 | * Remove a fd from the pollfd structure. | |
189 | */ | |
190 | int compat_poll_del(struct lttng_poll_event *events, int fd) | |
191 | { | |
d21b0d71 DG |
192 | int new_size, i, count = 0, ret; |
193 | struct compat_poll_event_array *current; | |
5eb91c98 | 194 | |
d21b0d71 | 195 | if (events == NULL || events->current.events == NULL || fd < 0) { |
5eb91c98 DG |
196 | ERR("Wrong arguments for poll del"); |
197 | goto error; | |
198 | } | |
199 | ||
d21b0d71 DG |
200 | /* Ease our life a bit. */ |
201 | current = &events->current; | |
5eb91c98 DG |
202 | |
203 | /* Safety check on size */ | |
204 | if (new_size > poll_max_size) { | |
205 | new_size = poll_max_size; | |
206 | } | |
207 | ||
d21b0d71 DG |
208 | /* Check if we need to shrink it down. */ |
209 | if ((current->nb_fd << 1UL) <= current->alloc_size && | |
210 | current->nb_fd >= current->init_size) { | |
211 | /* | |
212 | * Shrink if nb_fd multiplied by two is <= than the actual size and we | |
213 | * are above the initial size. | |
214 | */ | |
215 | new_size = current->alloc_size >> 1UL; | |
216 | ret = resize_poll_event(current, new_size); | |
217 | if (ret < 0) { | |
218 | goto error; | |
219 | } | |
220 | events->need_realloc = 1; | |
5eb91c98 DG |
221 | } |
222 | ||
d21b0d71 | 223 | for (i = 0; i < current->nb_fd; i++) { |
5eb91c98 | 224 | /* Don't put back the fd we want to delete */ |
d21b0d71 DG |
225 | if (current->events[i].fd != fd) { |
226 | current->events[count].fd = current->events[i].fd; | |
227 | current->events[count].events = current->events[i].events; | |
5eb91c98 DG |
228 | count++; |
229 | } | |
230 | } | |
231 | ||
d21b0d71 DG |
232 | current->nb_fd--; |
233 | events->need_update = 1; | |
5eb91c98 DG |
234 | |
235 | return 0; | |
236 | ||
237 | error: | |
238 | return -1; | |
239 | } | |
240 | ||
241 | /* | |
242 | * Wait on poll() with timeout. Blocking call. | |
243 | */ | |
244 | int compat_poll_wait(struct lttng_poll_event *events, int timeout) | |
245 | { | |
246 | int ret; | |
247 | ||
d21b0d71 | 248 | if (events == NULL || events->current.events == NULL) { |
5eb91c98 DG |
249 | ERR("poll wait arguments error"); |
250 | goto error; | |
251 | } | |
252 | ||
d21b0d71 DG |
253 | if (events->current.nb_fd == 0) { |
254 | /* Return an invalid error to be consistent with epoll. */ | |
255 | errno = EINVAL; | |
256 | goto error; | |
257 | } | |
258 | ||
259 | if (events->need_update) { | |
260 | ret = update_current_events(events); | |
261 | if (ret < 0) { | |
262 | errno = ENOMEM; | |
263 | goto error; | |
264 | } | |
265 | } | |
266 | ||
267 | ret = poll(events->wait.events, events->wait.nb_fd, timeout); | |
5eb91c98 DG |
268 | if (ret < 0) { |
269 | /* At this point, every error is fatal */ | |
270 | perror("poll wait"); | |
271 | goto error; | |
272 | } | |
273 | ||
9ddba525 DG |
274 | /* |
275 | * poll() should always iterate on all FDs since we handle the pollset in | |
276 | * user space and after poll returns, we have to try every fd for a match. | |
277 | */ | |
d21b0d71 | 278 | return events->wait.nb_fd; |
5eb91c98 DG |
279 | |
280 | error: | |
281 | return -1; | |
282 | } | |
283 | ||
284 | /* | |
285 | * Setup poll set maximum size. | |
286 | */ | |
287 | void compat_poll_set_max_size(void) | |
288 | { | |
289 | int ret; | |
290 | struct rlimit lim; | |
291 | ||
292 | /* Default value */ | |
990570ed | 293 | poll_max_size = DEFAULT_POLL_SIZE; |
5eb91c98 DG |
294 | |
295 | ret = getrlimit(RLIMIT_NOFILE, &lim); | |
296 | if (ret < 0) { | |
297 | perror("getrlimit poll RLIMIT_NOFILE"); | |
298 | return; | |
299 | } | |
300 | ||
301 | poll_max_size = lim.rlim_cur; | |
d21b0d71 | 302 | if (poll_max_size == 0) { |
5eb91c98 | 303 | /* Extra precaution */ |
990570ed | 304 | poll_max_size = DEFAULT_POLL_SIZE; |
5eb91c98 DG |
305 | } |
306 | ||
307 | DBG("poll set max size set to %u", poll_max_size); | |
308 | } |