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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 <stdlib.h> | |
19 | #include <sys/resource.h> | |
20 | #include <sys/time.h> | |
21 | ||
22 | #include <lttngerr.h> | |
23 | ||
24 | #include "poll.h" | |
25 | ||
26 | unsigned int poll_max_size; | |
27 | ||
28 | /* | |
29 | * Create pollfd data structure. | |
30 | */ | |
31 | int compat_poll_create(struct lttng_poll_event *events, int size) | |
32 | { | |
33 | if (events == NULL || size <= 0) { | |
34 | ERR("Wrong arguments for poll create"); | |
35 | goto error; | |
36 | } | |
37 | ||
38 | /* Don't bust the limit here */ | |
39 | if (size > poll_max_size) { | |
40 | size = poll_max_size; | |
41 | } | |
42 | ||
43 | /* This *must* be freed by using lttng_poll_free() */ | |
44 | events->events = zmalloc(size * sizeof(struct pollfd)); | |
45 | if (events->events == NULL) { | |
ba7f0ae5 | 46 | perror("zmalloc struct pollfd"); |
5eb91c98 DG |
47 | goto error; |
48 | } | |
49 | ||
50 | events->events_size = size; | |
51 | events->nb_fd = 0; | |
52 | ||
53 | return 0; | |
54 | ||
55 | error: | |
56 | return -1; | |
57 | } | |
58 | ||
59 | /* | |
60 | * Add fd to pollfd data structure with requested events. | |
61 | */ | |
62 | int compat_poll_add(struct lttng_poll_event *events, int fd, | |
63 | uint32_t req_events) | |
64 | { | |
65 | int new_size; | |
66 | struct pollfd *ptr; | |
67 | ||
68 | if (events == NULL || events->events == NULL || fd < 0) { | |
69 | ERR("Bad compat poll add arguments"); | |
70 | goto error; | |
71 | } | |
72 | ||
73 | /* Reallocate pollfd structure by a factor of 2 if needed. */ | |
74 | if (events->nb_fd >= events->events_size) { | |
75 | new_size = 2 * events->events_size; | |
76 | ptr = realloc(events->events, new_size * sizeof(struct pollfd)); | |
77 | if (ptr == NULL) { | |
78 | perror("realloc poll add"); | |
79 | goto error; | |
80 | } | |
81 | events->events = ptr; | |
82 | events->events_size = new_size; | |
83 | } | |
84 | ||
85 | events->events[events->nb_fd].fd = fd; | |
86 | events->events[events->nb_fd].events = req_events; | |
87 | events->nb_fd++; | |
88 | ||
89 | DBG("fd %d of %d added to pollfd", fd, events->nb_fd); | |
90 | ||
91 | return 0; | |
92 | ||
93 | error: | |
94 | return -1; | |
95 | } | |
96 | ||
97 | /* | |
98 | * Remove a fd from the pollfd structure. | |
99 | */ | |
100 | int compat_poll_del(struct lttng_poll_event *events, int fd) | |
101 | { | |
102 | int new_size, i, count = 0; | |
103 | struct pollfd *old = NULL, *new = NULL; | |
104 | ||
105 | if (events == NULL || events->events == NULL || fd < 0) { | |
106 | ERR("Wrong arguments for poll del"); | |
107 | goto error; | |
108 | } | |
109 | ||
110 | old = events->events; | |
111 | new_size = events->events_size - 1; | |
112 | ||
113 | /* Safety check on size */ | |
114 | if (new_size > poll_max_size) { | |
115 | new_size = poll_max_size; | |
116 | } | |
117 | ||
118 | new = zmalloc(new_size * sizeof(struct pollfd)); | |
119 | if (new == NULL) { | |
ba7f0ae5 | 120 | perror("zmalloc poll del"); |
5eb91c98 DG |
121 | goto error; |
122 | } | |
123 | ||
124 | for (i = 0; i < events->events_size; i++) { | |
125 | /* Don't put back the fd we want to delete */ | |
126 | if (old[i].fd != fd) { | |
127 | new[count].fd = old[i].fd; | |
128 | new[count].events = old[i].events; | |
129 | count++; | |
130 | } | |
131 | } | |
132 | ||
133 | events->events_size = new_size; | |
134 | events->events = new; | |
135 | events->nb_fd--; | |
136 | ||
137 | free(old); | |
138 | ||
139 | return 0; | |
140 | ||
141 | error: | |
142 | return -1; | |
143 | } | |
144 | ||
145 | /* | |
146 | * Wait on poll() with timeout. Blocking call. | |
147 | */ | |
148 | int compat_poll_wait(struct lttng_poll_event *events, int timeout) | |
149 | { | |
150 | int ret; | |
151 | ||
152 | if (events == NULL || events->events == NULL || | |
153 | events->events_size < events->nb_fd) { | |
154 | ERR("poll wait arguments error"); | |
155 | goto error; | |
156 | } | |
157 | ||
158 | ret = poll(events->events, events->nb_fd, timeout); | |
159 | if (ret < 0) { | |
160 | /* At this point, every error is fatal */ | |
161 | perror("poll wait"); | |
162 | goto error; | |
163 | } | |
164 | ||
165 | return ret; | |
166 | ||
167 | error: | |
168 | return -1; | |
169 | } | |
170 | ||
171 | /* | |
172 | * Setup poll set maximum size. | |
173 | */ | |
174 | void compat_poll_set_max_size(void) | |
175 | { | |
176 | int ret; | |
177 | struct rlimit lim; | |
178 | ||
179 | /* Default value */ | |
180 | poll_max_size = LTTNG_POLL_DEFAULT_SIZE; | |
181 | ||
182 | ret = getrlimit(RLIMIT_NOFILE, &lim); | |
183 | if (ret < 0) { | |
184 | perror("getrlimit poll RLIMIT_NOFILE"); | |
185 | return; | |
186 | } | |
187 | ||
188 | poll_max_size = lim.rlim_cur; | |
189 | if (poll_max_size <= 0) { | |
190 | /* Extra precaution */ | |
191 | poll_max_size = LTTNG_POLL_DEFAULT_SIZE; | |
192 | } | |
193 | ||
194 | DBG("poll set max size set to %u", poll_max_size); | |
195 | } |