578dd2e455a0ada7573972b9aebf913369208e7c
[lttng-tools.git] / ltt-sessiond / compat / compat-epoll.c
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>
24
25 #include <lttngerr.h>
26
27 #include "poll.h"
28
29 unsigned int poll_max_size;
30
31 /*
32 * Create epoll set and allocate returned events structure.
33 */
34 int compat_epoll_create(struct lttng_poll_event *events, int size, int flags)
35 {
36 int ret;
37
38 if (events == NULL || size <= 0) {
39 goto error;
40 }
41
42 /* Don't bust the limit here */
43 if (size > poll_max_size) {
44 size = poll_max_size;
45 }
46
47 ret = epoll_create1(flags);
48 if (ret < 0) {
49 /* At this point, every error is fatal */
50 perror("epoll_create1");
51 goto error;
52 }
53
54 events->epfd = ret;
55
56 /* This *must* be freed by using lttng_poll_free() */
57 events->events = zmalloc(size * sizeof(struct epoll_event));
58 if (events->events == NULL) {
59 perror("malloc epoll set");
60 goto error_close;
61 }
62
63 events->events_size = size;
64 events->nb_fd = 0;
65
66 return 0;
67
68 error_close:
69 close(events->epfd);
70 error:
71 return -1;
72 }
73
74 /*
75 * Add a fd to the epoll set with requesting events.
76 */
77 int compat_epoll_add(struct lttng_poll_event *events, int fd, uint32_t req_events)
78 {
79 int ret, new_size;
80 struct epoll_event ev, *ptr;
81
82 if (events == NULL || events->events == NULL || fd < 0) {
83 ERR("Bad compat epoll add arguments");
84 goto error;
85 }
86
87 ev.events = req_events;
88 ev.data.fd = fd;
89
90 ret = epoll_ctl(events->epfd, EPOLL_CTL_ADD, fd, &ev);
91 if (ret < 0) {
92 switch (errno) {
93 case EEXIST:
94 case ENOSPC:
95 case EPERM:
96 /* Print perror and goto end not failing. Show must go on. */
97 perror("epoll_ctl ADD");
98 goto end;
99 default:
100 perror("epoll_ctl ADD fatal");
101 goto error;
102 }
103 }
104
105 events->nb_fd++;
106
107 if (events->nb_fd >= events->events_size) {
108 new_size = 2 * events->events_size;
109 ptr = realloc(events->events, new_size * sizeof(struct epoll_event));
110 if (ptr == NULL) {
111 perror("realloc epoll add");
112 goto error;
113 }
114 events->events = ptr;
115 events->events_size = new_size;
116 }
117
118 end:
119 return 0;
120
121 error:
122 return -1;
123 }
124
125 /*
126 * Remove a fd from the epoll set.
127 */
128 int compat_epoll_del(struct lttng_poll_event *events, int fd)
129 {
130 int ret;
131
132 if (events == NULL || fd < 0) {
133 goto error;
134 }
135
136 ret = epoll_ctl(events->epfd, EPOLL_CTL_DEL, fd, NULL);
137 if (ret < 0) {
138 switch (errno) {
139 case ENOENT:
140 case EPERM:
141 /* Print perror and goto end not failing. Show must go on. */
142 perror("epoll_ctl DEL");
143 goto end;
144 default:
145 perror("epoll_ctl DEL fatal");
146 goto error;
147 }
148 perror("epoll_ctl del");
149 goto error;
150 }
151
152 events->nb_fd--;
153
154 end:
155 return 0;
156
157 error:
158 return -1;
159 }
160
161 /*
162 * Wait on epoll set. This is a blocking call of timeout value.
163 */
164 int compat_epoll_wait(struct lttng_poll_event *events, int timeout)
165 {
166 int ret;
167
168 if (events == NULL || events->events == NULL ||
169 events->events_size < events->nb_fd) {
170 ERR("Wrong arguments in compat_epoll_wait");
171 goto error;
172 }
173
174 ret = epoll_wait(events->epfd, events->events, events->nb_fd, timeout);
175 if (ret < 0) {
176 /* At this point, every error is fatal */
177 perror("epoll_wait");
178 goto error;
179 }
180
181 return ret;
182
183 error:
184 return -1;
185 }
186
187 /*
188 * Setup poll set maximum size.
189 */
190 void compat_epoll_set_max_size(void)
191 {
192 int ret, fd;
193 char buf[64];
194
195 poll_max_size = LTTNG_POLL_DEFAULT_SIZE;
196
197 fd = open(LTTNG_EPOLL_PROC_PATH, O_RDONLY);
198 if (fd < 0) {
199 return;
200 }
201
202 ret = read(fd, buf, sizeof(buf));
203 if (ret < 0) {
204 perror("read set max size");
205 goto error;
206 }
207
208 poll_max_size = atoi(buf);
209 if (poll_max_size <= 0) {
210 /* Extra precaution */
211 poll_max_size = LTTNG_POLL_DEFAULT_SIZE;
212 }
213
214 DBG("epoll set max size is %d", poll_max_size);
215
216 error:
217 close(fd);
218 }
This page took 0.033757 seconds and 4 git commands to generate.