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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 | ||
990570ed | 22 | #include <common/defaults.h> |
db758600 | 23 | #include <common/error.h> |
5eb91c98 DG |
24 | |
25 | #include "poll.h" | |
26 | ||
27 | unsigned int poll_max_size; | |
28 | ||
29 | /* | |
30 | * Create pollfd data structure. | |
31 | */ | |
32 | int compat_poll_create(struct lttng_poll_event *events, int size) | |
33 | { | |
34 | if (events == NULL || size <= 0) { | |
35 | ERR("Wrong arguments for poll create"); | |
36 | goto error; | |
37 | } | |
38 | ||
39 | /* Don't bust the limit here */ | |
40 | if (size > poll_max_size) { | |
41 | size = poll_max_size; | |
42 | } | |
43 | ||
44 | /* This *must* be freed by using lttng_poll_free() */ | |
45 | events->events = zmalloc(size * sizeof(struct pollfd)); | |
46 | if (events->events == NULL) { | |
ba7f0ae5 | 47 | perror("zmalloc struct pollfd"); |
5eb91c98 DG |
48 | goto error; |
49 | } | |
50 | ||
51 | events->events_size = size; | |
52 | events->nb_fd = 0; | |
53 | ||
54 | return 0; | |
55 | ||
56 | error: | |
57 | return -1; | |
58 | } | |
59 | ||
60 | /* | |
61 | * Add fd to pollfd data structure with requested events. | |
62 | */ | |
63 | int compat_poll_add(struct lttng_poll_event *events, int fd, | |
64 | uint32_t req_events) | |
65 | { | |
66 | int new_size; | |
67 | struct pollfd *ptr; | |
68 | ||
69 | if (events == NULL || events->events == NULL || fd < 0) { | |
70 | ERR("Bad compat poll add arguments"); | |
71 | goto error; | |
72 | } | |
73 | ||
74 | /* Reallocate pollfd structure by a factor of 2 if needed. */ | |
75 | if (events->nb_fd >= events->events_size) { | |
76 | new_size = 2 * events->events_size; | |
77 | ptr = realloc(events->events, new_size * sizeof(struct pollfd)); | |
78 | if (ptr == NULL) { | |
79 | perror("realloc poll add"); | |
80 | goto error; | |
81 | } | |
82 | events->events = ptr; | |
83 | events->events_size = new_size; | |
84 | } | |
85 | ||
86 | events->events[events->nb_fd].fd = fd; | |
87 | events->events[events->nb_fd].events = req_events; | |
88 | events->nb_fd++; | |
89 | ||
90 | DBG("fd %d of %d added to pollfd", fd, events->nb_fd); | |
91 | ||
92 | return 0; | |
93 | ||
94 | error: | |
95 | return -1; | |
96 | } | |
97 | ||
98 | /* | |
99 | * Remove a fd from the pollfd structure. | |
100 | */ | |
101 | int compat_poll_del(struct lttng_poll_event *events, int fd) | |
102 | { | |
103 | int new_size, i, count = 0; | |
104 | struct pollfd *old = NULL, *new = NULL; | |
105 | ||
106 | if (events == NULL || events->events == NULL || fd < 0) { | |
107 | ERR("Wrong arguments for poll del"); | |
108 | goto error; | |
109 | } | |
110 | ||
111 | old = events->events; | |
112 | new_size = events->events_size - 1; | |
113 | ||
114 | /* Safety check on size */ | |
115 | if (new_size > poll_max_size) { | |
116 | new_size = poll_max_size; | |
117 | } | |
118 | ||
119 | new = zmalloc(new_size * sizeof(struct pollfd)); | |
120 | if (new == NULL) { | |
ba7f0ae5 | 121 | perror("zmalloc poll del"); |
5eb91c98 DG |
122 | goto error; |
123 | } | |
124 | ||
125 | for (i = 0; i < events->events_size; i++) { | |
126 | /* Don't put back the fd we want to delete */ | |
127 | if (old[i].fd != fd) { | |
128 | new[count].fd = old[i].fd; | |
129 | new[count].events = old[i].events; | |
130 | count++; | |
131 | } | |
132 | } | |
133 | ||
134 | events->events_size = new_size; | |
135 | events->events = new; | |
136 | events->nb_fd--; | |
137 | ||
138 | free(old); | |
139 | ||
140 | return 0; | |
141 | ||
142 | error: | |
143 | return -1; | |
144 | } | |
145 | ||
146 | /* | |
147 | * Wait on poll() with timeout. Blocking call. | |
148 | */ | |
149 | int compat_poll_wait(struct lttng_poll_event *events, int timeout) | |
150 | { | |
151 | int ret; | |
152 | ||
153 | if (events == NULL || events->events == NULL || | |
154 | events->events_size < events->nb_fd) { | |
155 | ERR("poll wait arguments error"); | |
156 | goto error; | |
157 | } | |
158 | ||
159 | ret = poll(events->events, events->nb_fd, timeout); | |
160 | if (ret < 0) { | |
161 | /* At this point, every error is fatal */ | |
162 | perror("poll wait"); | |
163 | goto error; | |
164 | } | |
165 | ||
166 | return ret; | |
167 | ||
168 | error: | |
169 | return -1; | |
170 | } | |
171 | ||
172 | /* | |
173 | * Setup poll set maximum size. | |
174 | */ | |
175 | void compat_poll_set_max_size(void) | |
176 | { | |
177 | int ret; | |
178 | struct rlimit lim; | |
179 | ||
180 | /* Default value */ | |
990570ed | 181 | poll_max_size = DEFAULT_POLL_SIZE; |
5eb91c98 DG |
182 | |
183 | ret = getrlimit(RLIMIT_NOFILE, &lim); | |
184 | if (ret < 0) { | |
185 | perror("getrlimit poll RLIMIT_NOFILE"); | |
186 | return; | |
187 | } | |
188 | ||
189 | poll_max_size = lim.rlim_cur; | |
190 | if (poll_max_size <= 0) { | |
191 | /* Extra precaution */ | |
990570ed | 192 | poll_max_size = DEFAULT_POLL_SIZE; |
5eb91c98 DG |
193 | } |
194 | ||
195 | DBG("poll set max size set to %u", poll_max_size); | |
196 | } |