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5eb91c98 DG |
1 | /* |
2 | * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca> | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify it | |
5 | * under the terms of the GNU General Public License as published by the Free | |
6 | * Software Foundation; only version 2 of the License. | |
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 | * | |
13 | * You should have received a copy of the GNU General Public License along with | |
14 | * this program; if not, write to the Free Software Foundation, Inc., 59 Temple | |
15 | * Place - Suite 330, Boston, MA 02111-1307, USA. | |
16 | */ | |
17 | ||
18 | #include <fcntl.h> | |
19 | #include <limits.h> | |
20 | #include <stdlib.h> | |
21 | #include <sys/types.h> | |
22 | #include <sys/stat.h> | |
23 | #include <unistd.h> | |
3bd1e081 | 24 | #include <config.h> |
5eb91c98 | 25 | |
db758600 | 26 | #include <common/error.h> |
990570ed | 27 | #include <common/defaults.h> |
5eb91c98 DG |
28 | |
29 | #include "poll.h" | |
30 | ||
31 | unsigned int poll_max_size; | |
32 | ||
33 | /* | |
34 | * Create epoll set and allocate returned events structure. | |
35 | */ | |
36 | int compat_epoll_create(struct lttng_poll_event *events, int size, int flags) | |
37 | { | |
38 | int ret; | |
39 | ||
40 | if (events == NULL || size <= 0) { | |
41 | goto error; | |
42 | } | |
43 | ||
44 | /* Don't bust the limit here */ | |
45 | if (size > poll_max_size) { | |
46 | size = poll_max_size; | |
47 | } | |
48 | ||
49 | ret = epoll_create1(flags); | |
50 | if (ret < 0) { | |
51 | /* At this point, every error is fatal */ | |
52 | perror("epoll_create1"); | |
53 | goto error; | |
54 | } | |
55 | ||
56 | events->epfd = ret; | |
57 | ||
58 | /* This *must* be freed by using lttng_poll_free() */ | |
59 | events->events = zmalloc(size * sizeof(struct epoll_event)); | |
60 | if (events->events == NULL) { | |
ba7f0ae5 | 61 | perror("zmalloc epoll set"); |
5eb91c98 DG |
62 | goto error_close; |
63 | } | |
64 | ||
65 | events->events_size = size; | |
66 | events->nb_fd = 0; | |
67 | ||
68 | return 0; | |
69 | ||
70 | error_close: | |
71 | close(events->epfd); | |
72 | error: | |
73 | return -1; | |
74 | } | |
75 | ||
76 | /* | |
77 | * Add a fd to the epoll set with requesting events. | |
78 | */ | |
79 | int compat_epoll_add(struct lttng_poll_event *events, int fd, uint32_t req_events) | |
80 | { | |
81 | int ret, new_size; | |
82 | struct epoll_event ev, *ptr; | |
83 | ||
84 | if (events == NULL || events->events == NULL || fd < 0) { | |
85 | ERR("Bad compat epoll add arguments"); | |
86 | goto error; | |
87 | } | |
88 | ||
89 | ev.events = req_events; | |
90 | ev.data.fd = fd; | |
91 | ||
92 | ret = epoll_ctl(events->epfd, EPOLL_CTL_ADD, fd, &ev); | |
93 | if (ret < 0) { | |
94 | switch (errno) { | |
95 | case EEXIST: | |
b7a6b49f DG |
96 | /* If exist, it's OK. */ |
97 | goto end; | |
5eb91c98 DG |
98 | case ENOSPC: |
99 | case EPERM: | |
100 | /* Print perror and goto end not failing. Show must go on. */ | |
101 | perror("epoll_ctl ADD"); | |
102 | goto end; | |
103 | default: | |
104 | perror("epoll_ctl ADD fatal"); | |
105 | goto error; | |
106 | } | |
107 | } | |
108 | ||
109 | events->nb_fd++; | |
110 | ||
111 | if (events->nb_fd >= events->events_size) { | |
112 | new_size = 2 * events->events_size; | |
113 | ptr = realloc(events->events, new_size * sizeof(struct epoll_event)); | |
114 | if (ptr == NULL) { | |
115 | perror("realloc epoll add"); | |
116 | goto error; | |
117 | } | |
118 | events->events = ptr; | |
119 | events->events_size = new_size; | |
120 | } | |
121 | ||
122 | end: | |
123 | return 0; | |
124 | ||
125 | error: | |
126 | return -1; | |
127 | } | |
128 | ||
129 | /* | |
130 | * Remove a fd from the epoll set. | |
131 | */ | |
132 | int compat_epoll_del(struct lttng_poll_event *events, int fd) | |
133 | { | |
134 | int ret; | |
135 | ||
136 | if (events == NULL || fd < 0) { | |
137 | goto error; | |
138 | } | |
139 | ||
140 | ret = epoll_ctl(events->epfd, EPOLL_CTL_DEL, fd, NULL); | |
141 | if (ret < 0) { | |
142 | switch (errno) { | |
143 | case ENOENT: | |
144 | case EPERM: | |
145 | /* Print perror and goto end not failing. Show must go on. */ | |
146 | perror("epoll_ctl DEL"); | |
147 | goto end; | |
148 | default: | |
149 | perror("epoll_ctl DEL fatal"); | |
150 | goto error; | |
151 | } | |
152 | perror("epoll_ctl del"); | |
153 | goto error; | |
154 | } | |
155 | ||
156 | events->nb_fd--; | |
157 | ||
158 | end: | |
159 | return 0; | |
160 | ||
161 | error: | |
162 | return -1; | |
163 | } | |
164 | ||
165 | /* | |
166 | * Wait on epoll set. This is a blocking call of timeout value. | |
167 | */ | |
168 | int compat_epoll_wait(struct lttng_poll_event *events, int timeout) | |
169 | { | |
170 | int ret; | |
171 | ||
172 | if (events == NULL || events->events == NULL || | |
173 | events->events_size < events->nb_fd) { | |
174 | ERR("Wrong arguments in compat_epoll_wait"); | |
175 | goto error; | |
176 | } | |
177 | ||
3ada8405 DG |
178 | do { |
179 | ret = epoll_wait(events->epfd, events->events, events->nb_fd, timeout); | |
180 | } while (ret == -1 && errno == EINTR); | |
5eb91c98 DG |
181 | if (ret < 0) { |
182 | /* At this point, every error is fatal */ | |
183 | perror("epoll_wait"); | |
184 | goto error; | |
185 | } | |
186 | ||
187 | return ret; | |
188 | ||
189 | error: | |
190 | return -1; | |
191 | } | |
192 | ||
193 | /* | |
194 | * Setup poll set maximum size. | |
195 | */ | |
196 | void compat_epoll_set_max_size(void) | |
197 | { | |
198 | int ret, fd; | |
199 | char buf[64]; | |
200 | ||
990570ed | 201 | poll_max_size = DEFAULT_POLL_SIZE; |
5eb91c98 | 202 | |
990570ed | 203 | fd = open(COMPAT_EPOLL_PROC_PATH, O_RDONLY); |
5eb91c98 DG |
204 | if (fd < 0) { |
205 | return; | |
206 | } | |
207 | ||
208 | ret = read(fd, buf, sizeof(buf)); | |
209 | if (ret < 0) { | |
210 | perror("read set max size"); | |
211 | goto error; | |
212 | } | |
213 | ||
214 | poll_max_size = atoi(buf); | |
215 | if (poll_max_size <= 0) { | |
216 | /* Extra precaution */ | |
990570ed | 217 | poll_max_size = DEFAULT_POLL_SIZE; |
5eb91c98 DG |
218 | } |
219 | ||
220 | DBG("epoll set max size is %d", poll_max_size); | |
221 | ||
222 | error: | |
223 | close(fd); | |
224 | } |