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 |
d21b0d71 | 19 | #include <assert.h> |
5eb91c98 DG |
20 | #include <fcntl.h> |
21 | #include <limits.h> | |
22 | #include <stdlib.h> | |
23 | #include <sys/types.h> | |
24 | #include <sys/stat.h> | |
25 | #include <unistd.h> | |
3bd1e081 | 26 | #include <config.h> |
5eb91c98 | 27 | |
db758600 | 28 | #include <common/error.h> |
990570ed | 29 | #include <common/defaults.h> |
cfa9a5a2 DG |
30 | #include <common/macros.h> |
31 | #include <common/utils.h> | |
5eb91c98 DG |
32 | |
33 | #include "poll.h" | |
34 | ||
35 | unsigned int poll_max_size; | |
36 | ||
d21b0d71 DG |
37 | /* |
38 | * Resize the epoll events structure of the new size. | |
39 | * | |
40 | * Return 0 on success or else -1 with the current events pointer untouched. | |
41 | */ | |
42 | static int resize_poll_event(struct lttng_poll_event *events, | |
43 | uint32_t new_size) | |
44 | { | |
45 | struct epoll_event *ptr; | |
46 | ||
47 | assert(events); | |
48 | ||
49 | ptr = realloc(events->events, new_size * sizeof(*ptr)); | |
50 | if (ptr == NULL) { | |
51 | PERROR("realloc epoll add"); | |
52 | goto error; | |
53 | } | |
53efb85a MD |
54 | if (new_size > events->alloc_size) { |
55 | /* Zero newly allocated memory */ | |
56 | memset(ptr + events->alloc_size, 0, | |
57 | (new_size - events->alloc_size) * sizeof(*ptr)); | |
58 | } | |
d21b0d71 DG |
59 | events->events = ptr; |
60 | events->alloc_size = new_size; | |
61 | ||
62 | return 0; | |
63 | ||
64 | error: | |
65 | return -1; | |
66 | } | |
67 | ||
5eb91c98 DG |
68 | /* |
69 | * Create epoll set and allocate returned events structure. | |
70 | */ | |
71 | int compat_epoll_create(struct lttng_poll_event *events, int size, int flags) | |
72 | { | |
73 | int ret; | |
74 | ||
75 | if (events == NULL || size <= 0) { | |
76 | goto error; | |
77 | } | |
78 | ||
b85e60c1 MD |
79 | if (!poll_max_size) { |
80 | ERR("poll_max_size not initialized yet"); | |
81 | goto error; | |
82 | } | |
83 | ||
5eb91c98 | 84 | /* Don't bust the limit here */ |
b85e60c1 | 85 | if (size > poll_max_size) { |
5eb91c98 DG |
86 | size = poll_max_size; |
87 | } | |
88 | ||
f263b7fd | 89 | ret = compat_glibc_epoll_create(size, flags); |
5eb91c98 DG |
90 | if (ret < 0) { |
91 | /* At this point, every error is fatal */ | |
4c462e79 | 92 | PERROR("epoll_create1"); |
5eb91c98 DG |
93 | goto error; |
94 | } | |
95 | ||
96 | events->epfd = ret; | |
97 | ||
98 | /* This *must* be freed by using lttng_poll_free() */ | |
99 | events->events = zmalloc(size * sizeof(struct epoll_event)); | |
100 | if (events->events == NULL) { | |
4c462e79 | 101 | PERROR("zmalloc epoll set"); |
5eb91c98 DG |
102 | goto error_close; |
103 | } | |
104 | ||
d21b0d71 | 105 | events->alloc_size = events->init_size = size; |
5eb91c98 DG |
106 | events->nb_fd = 0; |
107 | ||
108 | return 0; | |
109 | ||
110 | error_close: | |
4c462e79 MD |
111 | ret = close(events->epfd); |
112 | if (ret) { | |
113 | PERROR("close"); | |
114 | } | |
5eb91c98 DG |
115 | error: |
116 | return -1; | |
117 | } | |
118 | ||
119 | /* | |
120 | * Add a fd to the epoll set with requesting events. | |
121 | */ | |
122 | int compat_epoll_add(struct lttng_poll_event *events, int fd, uint32_t req_events) | |
123 | { | |
d21b0d71 DG |
124 | int ret; |
125 | struct epoll_event ev; | |
5eb91c98 DG |
126 | |
127 | if (events == NULL || events->events == NULL || fd < 0) { | |
128 | ERR("Bad compat epoll add arguments"); | |
129 | goto error; | |
130 | } | |
131 | ||
53efb85a MD |
132 | /* |
133 | * Zero struct epoll_event to ensure all representations of its | |
134 | * union are zeroed. | |
135 | */ | |
136 | memset(&ev, 0, sizeof(ev)); | |
5eb91c98 DG |
137 | ev.events = req_events; |
138 | ev.data.fd = fd; | |
139 | ||
140 | ret = epoll_ctl(events->epfd, EPOLL_CTL_ADD, fd, &ev); | |
141 | if (ret < 0) { | |
142 | switch (errno) { | |
143 | case EEXIST: | |
b7a6b49f DG |
144 | /* If exist, it's OK. */ |
145 | goto end; | |
5eb91c98 DG |
146 | case ENOSPC: |
147 | case EPERM: | |
4c462e79 MD |
148 | /* Print PERROR and goto end not failing. Show must go on. */ |
149 | PERROR("epoll_ctl ADD"); | |
5eb91c98 DG |
150 | goto end; |
151 | default: | |
4c462e79 | 152 | PERROR("epoll_ctl ADD fatal"); |
5eb91c98 DG |
153 | goto error; |
154 | } | |
155 | } | |
156 | ||
157 | events->nb_fd++; | |
158 | ||
5eb91c98 DG |
159 | end: |
160 | return 0; | |
161 | ||
162 | error: | |
163 | return -1; | |
164 | } | |
165 | ||
166 | /* | |
167 | * Remove a fd from the epoll set. | |
168 | */ | |
169 | int compat_epoll_del(struct lttng_poll_event *events, int fd) | |
170 | { | |
171 | int ret; | |
172 | ||
b85e60c1 | 173 | if (events == NULL || fd < 0 || events->nb_fd == 0) { |
5eb91c98 DG |
174 | goto error; |
175 | } | |
176 | ||
177 | ret = epoll_ctl(events->epfd, EPOLL_CTL_DEL, fd, NULL); | |
178 | if (ret < 0) { | |
179 | switch (errno) { | |
180 | case ENOENT: | |
181 | case EPERM: | |
4c462e79 MD |
182 | /* Print PERROR and goto end not failing. Show must go on. */ |
183 | PERROR("epoll_ctl DEL"); | |
5eb91c98 DG |
184 | goto end; |
185 | default: | |
4c462e79 | 186 | PERROR("epoll_ctl DEL fatal"); |
5eb91c98 DG |
187 | goto error; |
188 | } | |
5eb91c98 DG |
189 | } |
190 | ||
191 | events->nb_fd--; | |
192 | ||
193 | end: | |
194 | return 0; | |
195 | ||
196 | error: | |
197 | return -1; | |
198 | } | |
199 | ||
200 | /* | |
201 | * Wait on epoll set. This is a blocking call of timeout value. | |
202 | */ | |
203 | int compat_epoll_wait(struct lttng_poll_event *events, int timeout) | |
204 | { | |
205 | int ret; | |
d21b0d71 | 206 | uint32_t new_size; |
5eb91c98 | 207 | |
d21b0d71 | 208 | if (events == NULL || events->events == NULL) { |
5eb91c98 DG |
209 | ERR("Wrong arguments in compat_epoll_wait"); |
210 | goto error; | |
211 | } | |
b85e60c1 MD |
212 | assert(events->nb_fd >= 0); |
213 | ||
214 | if (events->nb_fd == 0) { | |
215 | errno = EINVAL; | |
216 | return -1; | |
217 | } | |
5eb91c98 | 218 | |
d21b0d71 DG |
219 | /* |
220 | * Resize if needed before waiting. We could either expand the array or | |
221 | * shrink it down. It's important to note that after this step, we are | |
222 | * ensured that the events argument of the epoll_wait call will be large | |
223 | * enough to hold every possible returned events. | |
224 | */ | |
b85e60c1 MD |
225 | new_size = 1U << utils_get_count_order_u32(events->nb_fd); |
226 | if (new_size != events->alloc_size && new_size >= events->init_size) { | |
d21b0d71 DG |
227 | ret = resize_poll_event(events, new_size); |
228 | if (ret < 0) { | |
229 | /* ENOMEM problem at this point. */ | |
230 | goto error; | |
231 | } | |
232 | } | |
233 | ||
3ada8405 DG |
234 | do { |
235 | ret = epoll_wait(events->epfd, events->events, events->nb_fd, timeout); | |
236 | } while (ret == -1 && errno == EINTR); | |
5eb91c98 DG |
237 | if (ret < 0) { |
238 | /* At this point, every error is fatal */ | |
4c462e79 | 239 | PERROR("epoll_wait"); |
5eb91c98 DG |
240 | goto error; |
241 | } | |
242 | ||
9ddba525 DG |
243 | /* |
244 | * Since the returned events are set sequentially in the "events" structure | |
245 | * we only need to return the epoll_wait value and iterate over it. | |
246 | */ | |
5eb91c98 DG |
247 | return ret; |
248 | ||
249 | error: | |
250 | return -1; | |
251 | } | |
252 | ||
253 | /* | |
254 | * Setup poll set maximum size. | |
255 | */ | |
b85e60c1 | 256 | int compat_epoll_set_max_size(void) |
5eb91c98 | 257 | { |
b85e60c1 | 258 | int ret, fd, retval = 0; |
13021756 | 259 | ssize_t size_ret; |
5eb91c98 DG |
260 | char buf[64]; |
261 | ||
990570ed | 262 | fd = open(COMPAT_EPOLL_PROC_PATH, O_RDONLY); |
5eb91c98 | 263 | if (fd < 0) { |
b85e60c1 MD |
264 | retval = -1; |
265 | goto end; | |
5eb91c98 DG |
266 | } |
267 | ||
6cd525e8 MD |
268 | size_ret = lttng_read(fd, buf, sizeof(buf)); |
269 | /* | |
270 | * Allow reading a file smaller than buf, but keep space for | |
271 | * final \0. | |
272 | */ | |
273 | if (size_ret < 0 || size_ret >= sizeof(buf)) { | |
4c462e79 | 274 | PERROR("read set max size"); |
b85e60c1 MD |
275 | retval = -1; |
276 | goto end_read; | |
5eb91c98 | 277 | } |
6cd525e8 | 278 | buf[size_ret] = '\0'; |
5eb91c98 | 279 | poll_max_size = atoi(buf); |
b85e60c1 | 280 | end_read: |
4c462e79 MD |
281 | ret = close(fd); |
282 | if (ret) { | |
283 | PERROR("close"); | |
284 | } | |
b85e60c1 MD |
285 | end: |
286 | if (!poll_max_size) { | |
287 | poll_max_size = DEFAULT_POLL_SIZE; | |
288 | } | |
289 | DBG("epoll set max size is %d", poll_max_size); | |
290 | return retval; | |
5eb91c98 | 291 | } |