Commit | Line | Data |
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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 | ||
4c462e79 | 18 | #define _GNU_SOURCE |
6c1c0768 | 19 | #define _LGPL_SOURCE |
d21b0d71 | 20 | #include <assert.h> |
5eb91c98 DG |
21 | #include <fcntl.h> |
22 | #include <limits.h> | |
23 | #include <stdlib.h> | |
24 | #include <sys/types.h> | |
25 | #include <sys/stat.h> | |
26 | #include <unistd.h> | |
3bd1e081 | 27 | #include <config.h> |
5eb91c98 | 28 | |
db758600 | 29 | #include <common/error.h> |
990570ed | 30 | #include <common/defaults.h> |
cfa9a5a2 DG |
31 | #include <common/macros.h> |
32 | #include <common/utils.h> | |
5eb91c98 DG |
33 | |
34 | #include "poll.h" | |
35 | ||
36 | unsigned int poll_max_size; | |
37 | ||
d21b0d71 DG |
38 | /* |
39 | * Resize the epoll events structure of the new size. | |
40 | * | |
41 | * Return 0 on success or else -1 with the current events pointer untouched. | |
42 | */ | |
43 | static int resize_poll_event(struct lttng_poll_event *events, | |
44 | uint32_t new_size) | |
45 | { | |
46 | struct epoll_event *ptr; | |
47 | ||
48 | assert(events); | |
49 | ||
50 | ptr = realloc(events->events, new_size * sizeof(*ptr)); | |
51 | if (ptr == NULL) { | |
52 | PERROR("realloc epoll add"); | |
53 | goto error; | |
54 | } | |
53efb85a MD |
55 | if (new_size > events->alloc_size) { |
56 | /* Zero newly allocated memory */ | |
57 | memset(ptr + events->alloc_size, 0, | |
58 | (new_size - events->alloc_size) * sizeof(*ptr)); | |
59 | } | |
d21b0d71 DG |
60 | events->events = ptr; |
61 | events->alloc_size = new_size; | |
62 | ||
63 | return 0; | |
64 | ||
65 | error: | |
66 | return -1; | |
67 | } | |
68 | ||
5eb91c98 DG |
69 | /* |
70 | * Create epoll set and allocate returned events structure. | |
71 | */ | |
72 | int compat_epoll_create(struct lttng_poll_event *events, int size, int flags) | |
73 | { | |
74 | int ret; | |
75 | ||
76 | if (events == NULL || size <= 0) { | |
77 | goto error; | |
78 | } | |
79 | ||
80 | /* Don't bust the limit here */ | |
fb3a43a9 | 81 | if (size > poll_max_size && poll_max_size != 0) { |
5eb91c98 DG |
82 | size = poll_max_size; |
83 | } | |
84 | ||
f263b7fd | 85 | ret = compat_glibc_epoll_create(size, flags); |
5eb91c98 DG |
86 | if (ret < 0) { |
87 | /* At this point, every error is fatal */ | |
4c462e79 | 88 | PERROR("epoll_create1"); |
5eb91c98 DG |
89 | goto error; |
90 | } | |
91 | ||
92 | events->epfd = ret; | |
93 | ||
94 | /* This *must* be freed by using lttng_poll_free() */ | |
95 | events->events = zmalloc(size * sizeof(struct epoll_event)); | |
96 | if (events->events == NULL) { | |
4c462e79 | 97 | PERROR("zmalloc epoll set"); |
5eb91c98 DG |
98 | goto error_close; |
99 | } | |
100 | ||
d21b0d71 | 101 | events->alloc_size = events->init_size = size; |
5eb91c98 DG |
102 | events->nb_fd = 0; |
103 | ||
104 | return 0; | |
105 | ||
106 | error_close: | |
4c462e79 MD |
107 | ret = close(events->epfd); |
108 | if (ret) { | |
109 | PERROR("close"); | |
110 | } | |
5eb91c98 DG |
111 | error: |
112 | return -1; | |
113 | } | |
114 | ||
115 | /* | |
116 | * Add a fd to the epoll set with requesting events. | |
117 | */ | |
118 | int compat_epoll_add(struct lttng_poll_event *events, int fd, uint32_t req_events) | |
119 | { | |
d21b0d71 DG |
120 | int ret; |
121 | struct epoll_event ev; | |
5eb91c98 DG |
122 | |
123 | if (events == NULL || events->events == NULL || fd < 0) { | |
124 | ERR("Bad compat epoll add arguments"); | |
125 | goto error; | |
126 | } | |
127 | ||
53efb85a MD |
128 | /* |
129 | * Zero struct epoll_event to ensure all representations of its | |
130 | * union are zeroed. | |
131 | */ | |
132 | memset(&ev, 0, sizeof(ev)); | |
5eb91c98 DG |
133 | ev.events = req_events; |
134 | ev.data.fd = fd; | |
135 | ||
136 | ret = epoll_ctl(events->epfd, EPOLL_CTL_ADD, fd, &ev); | |
137 | if (ret < 0) { | |
138 | switch (errno) { | |
139 | case EEXIST: | |
b7a6b49f DG |
140 | /* If exist, it's OK. */ |
141 | goto end; | |
5eb91c98 DG |
142 | case ENOSPC: |
143 | case EPERM: | |
4c462e79 MD |
144 | /* Print PERROR and goto end not failing. Show must go on. */ |
145 | PERROR("epoll_ctl ADD"); | |
5eb91c98 DG |
146 | goto end; |
147 | default: | |
4c462e79 | 148 | PERROR("epoll_ctl ADD fatal"); |
5eb91c98 DG |
149 | goto error; |
150 | } | |
151 | } | |
152 | ||
153 | events->nb_fd++; | |
154 | ||
5eb91c98 DG |
155 | end: |
156 | return 0; | |
157 | ||
158 | error: | |
159 | return -1; | |
160 | } | |
161 | ||
162 | /* | |
163 | * Remove a fd from the epoll set. | |
164 | */ | |
165 | int compat_epoll_del(struct lttng_poll_event *events, int fd) | |
166 | { | |
167 | int ret; | |
168 | ||
169 | if (events == NULL || fd < 0) { | |
170 | goto error; | |
171 | } | |
172 | ||
173 | ret = epoll_ctl(events->epfd, EPOLL_CTL_DEL, fd, NULL); | |
174 | if (ret < 0) { | |
175 | switch (errno) { | |
176 | case ENOENT: | |
177 | case EPERM: | |
4c462e79 MD |
178 | /* Print PERROR and goto end not failing. Show must go on. */ |
179 | PERROR("epoll_ctl DEL"); | |
5eb91c98 DG |
180 | goto end; |
181 | default: | |
4c462e79 | 182 | PERROR("epoll_ctl DEL fatal"); |
5eb91c98 DG |
183 | goto error; |
184 | } | |
5eb91c98 DG |
185 | } |
186 | ||
187 | events->nb_fd--; | |
188 | ||
189 | end: | |
190 | return 0; | |
191 | ||
192 | error: | |
193 | return -1; | |
194 | } | |
195 | ||
196 | /* | |
197 | * Wait on epoll set. This is a blocking call of timeout value. | |
198 | */ | |
199 | int compat_epoll_wait(struct lttng_poll_event *events, int timeout) | |
200 | { | |
201 | int ret; | |
d21b0d71 | 202 | uint32_t new_size; |
5eb91c98 | 203 | |
d21b0d71 | 204 | if (events == NULL || events->events == NULL) { |
5eb91c98 DG |
205 | ERR("Wrong arguments in compat_epoll_wait"); |
206 | goto error; | |
207 | } | |
208 | ||
d21b0d71 DG |
209 | /* |
210 | * Resize if needed before waiting. We could either expand the array or | |
211 | * shrink it down. It's important to note that after this step, we are | |
212 | * ensured that the events argument of the epoll_wait call will be large | |
213 | * enough to hold every possible returned events. | |
214 | */ | |
215 | if (events->nb_fd > events->alloc_size) { | |
216 | /* Expand if the nb_fd is higher than the actual size. */ | |
cfa9a5a2 DG |
217 | new_size = max_t(uint32_t, |
218 | 1U << utils_get_count_order_u32(events->nb_fd), | |
219 | events->alloc_size << 1UL); | |
d21b0d71 DG |
220 | } else if ((events->nb_fd << 1UL) <= events->alloc_size && |
221 | events->nb_fd >= events->init_size) { | |
222 | /* Shrink if nb_fd multiplied by two is <= than the actual size. */ | |
cfa9a5a2 DG |
223 | new_size = max_t(uint32_t, |
224 | utils_get_count_order_u32(events->nb_fd) >> 1U, | |
225 | events->alloc_size >> 1U); | |
d21b0d71 DG |
226 | } else { |
227 | /* Indicate that we don't want to resize. */ | |
228 | new_size = 0; | |
229 | } | |
230 | ||
231 | if (new_size) { | |
232 | ret = resize_poll_event(events, new_size); | |
233 | if (ret < 0) { | |
234 | /* ENOMEM problem at this point. */ | |
235 | goto error; | |
236 | } | |
237 | } | |
238 | ||
3ada8405 DG |
239 | do { |
240 | ret = epoll_wait(events->epfd, events->events, events->nb_fd, timeout); | |
241 | } while (ret == -1 && errno == EINTR); | |
5eb91c98 DG |
242 | if (ret < 0) { |
243 | /* At this point, every error is fatal */ | |
4c462e79 | 244 | PERROR("epoll_wait"); |
5eb91c98 DG |
245 | goto error; |
246 | } | |
247 | ||
9ddba525 DG |
248 | /* |
249 | * Since the returned events are set sequentially in the "events" structure | |
250 | * we only need to return the epoll_wait value and iterate over it. | |
251 | */ | |
5eb91c98 DG |
252 | return ret; |
253 | ||
254 | error: | |
255 | return -1; | |
256 | } | |
257 | ||
258 | /* | |
259 | * Setup poll set maximum size. | |
260 | */ | |
261 | void compat_epoll_set_max_size(void) | |
262 | { | |
263 | int ret, fd; | |
13021756 | 264 | ssize_t size_ret; |
5eb91c98 DG |
265 | char buf[64]; |
266 | ||
990570ed | 267 | poll_max_size = DEFAULT_POLL_SIZE; |
5eb91c98 | 268 | |
990570ed | 269 | fd = open(COMPAT_EPOLL_PROC_PATH, O_RDONLY); |
5eb91c98 DG |
270 | if (fd < 0) { |
271 | return; | |
272 | } | |
273 | ||
6cd525e8 MD |
274 | size_ret = lttng_read(fd, buf, sizeof(buf)); |
275 | /* | |
276 | * Allow reading a file smaller than buf, but keep space for | |
277 | * final \0. | |
278 | */ | |
279 | if (size_ret < 0 || size_ret >= sizeof(buf)) { | |
4c462e79 | 280 | PERROR("read set max size"); |
5eb91c98 DG |
281 | goto error; |
282 | } | |
6cd525e8 | 283 | buf[size_ret] = '\0'; |
5eb91c98 DG |
284 | |
285 | poll_max_size = atoi(buf); | |
d21b0d71 | 286 | if (poll_max_size == 0) { |
5eb91c98 | 287 | /* Extra precaution */ |
990570ed | 288 | poll_max_size = DEFAULT_POLL_SIZE; |
5eb91c98 DG |
289 | } |
290 | ||
291 | DBG("epoll set max size is %d", poll_max_size); | |
292 | ||
293 | error: | |
4c462e79 MD |
294 | ret = close(fd); |
295 | if (ret) { | |
296 | PERROR("close"); | |
297 | } | |
5eb91c98 | 298 | } |