2 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
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.
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
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.
22 #include <sys/resource.h>
25 #include <common/defaults.h>
26 #include <common/error.h>
27 #include <common/macros.h>
28 #include <common/utils.h>
32 unsigned int poll_max_size
;
35 * Resize the epoll events structure of the new size.
37 * Return 0 on success or else -1 with the current events pointer untouched.
39 static int resize_poll_event(struct compat_poll_event_array
*array
,
46 /* Refuse to resize the array more than the max size. */
47 if (new_size
> poll_max_size
) {
51 ptr
= realloc(array
->events
, new_size
* sizeof(*ptr
));
53 PERROR("realloc epoll add");
56 if (new_size
> array
->alloc_size
) {
57 /* Zero newly allocated memory */
58 memset(ptr
+ array
->alloc_size
, 0,
59 (new_size
- array
->alloc_size
) * sizeof(*ptr
));
62 array
->alloc_size
= new_size
;
71 * Update events with the current events object.
73 static int update_current_events(struct lttng_poll_event
*events
)
76 struct compat_poll_event_array
*current
, *wait
;
80 current
= &events
->current
;
83 wait
->nb_fd
= current
->nb_fd
;
84 if (current
->alloc_size
!= wait
->alloc_size
) {
85 ret
= resize_poll_event(wait
, current
->alloc_size
);
90 memcpy(wait
->events
, current
->events
,
91 current
->nb_fd
* sizeof(*current
->events
));
94 events
->need_update
= 0;
103 * Create pollfd data structure.
105 int compat_poll_create(struct lttng_poll_event
*events
, int size
)
107 struct compat_poll_event_array
*current
, *wait
;
109 if (events
== NULL
|| size
<= 0) {
110 ERR("Wrong arguments for poll create");
114 if (!poll_max_size
) {
115 ERR("poll_max_size not initialized yet");
119 /* Don't bust the limit here */
120 if (size
> poll_max_size
) {
121 size
= poll_max_size
;
124 /* Reset everything before begining the allocation. */
125 memset(events
, 0, sizeof(struct lttng_poll_event
));
127 current
= &events
->current
;
128 wait
= &events
->wait
;
130 /* This *must* be freed by using lttng_poll_free() */
131 wait
->events
= zmalloc(size
* sizeof(struct pollfd
));
132 if (wait
->events
== NULL
) {
133 PERROR("zmalloc struct pollfd");
137 wait
->alloc_size
= wait
->init_size
= size
;
139 current
->events
= zmalloc(size
* sizeof(struct pollfd
));
140 if (current
->events
== NULL
) {
141 PERROR("zmalloc struct current pollfd");
145 current
->alloc_size
= current
->init_size
= size
;
154 * Add fd to pollfd data structure with requested events.
156 int compat_poll_add(struct lttng_poll_event
*events
, int fd
,
159 int new_size
, ret
, i
;
160 struct compat_poll_event_array
*current
;
162 if (events
== NULL
|| events
->current
.events
== NULL
|| fd
< 0) {
163 ERR("Bad compat poll add arguments");
167 current
= &events
->current
;
169 /* Check if fd we are trying to add is already there. */
170 for (i
= 0; i
< current
->nb_fd
; i
++) {
171 if (current
->events
[i
].fd
== fd
) {
177 /* Resize array if needed. */
178 new_size
= 1U << utils_get_count_order_u32(current
->nb_fd
+ 1);
179 if (new_size
!= current
->alloc_size
&& new_size
>= current
->init_size
) {
180 ret
= resize_poll_event(current
, new_size
);
186 current
->events
[current
->nb_fd
].fd
= fd
;
187 current
->events
[current
->nb_fd
].events
= req_events
;
189 events
->need_update
= 1;
191 DBG("fd %d of %d added to pollfd", fd
, current
->nb_fd
);
200 * Remove a fd from the pollfd structure.
202 int compat_poll_del(struct lttng_poll_event
*events
, int fd
)
204 int new_size
, i
, count
= 0, ret
;
205 struct compat_poll_event_array
*current
;
207 if (events
== NULL
|| events
->current
.events
== NULL
|| fd
< 0) {
208 ERR("Wrong arguments for poll del");
212 /* Ease our life a bit. */
213 current
= &events
->current
;
215 for (i
= 0; i
< current
->nb_fd
; i
++) {
216 /* Don't put back the fd we want to delete */
217 if (current
->events
[i
].fd
!= fd
) {
218 current
->events
[count
].fd
= current
->events
[i
].fd
;
219 current
->events
[count
].events
= current
->events
[i
].events
;
223 /* No fd duplicate should be ever added into array. */
224 assert(current
->nb_fd
- 1 == count
);
225 current
->nb_fd
= count
;
227 /* Resize array if needed. */
228 new_size
= 1U << utils_get_count_order_u32(current
->nb_fd
);
229 if (new_size
!= current
->alloc_size
&& new_size
>= current
->init_size
) {
230 ret
= resize_poll_event(current
, new_size
);
236 events
->need_update
= 1;
245 * Wait on poll() with timeout. Blocking call.
247 int compat_poll_wait(struct lttng_poll_event
*events
, int timeout
)
251 if (events
== NULL
|| events
->current
.events
== NULL
) {
252 ERR("poll wait arguments error");
255 assert(events
->current
.nb_fd
>= 0);
257 if (events
->current
.nb_fd
== 0) {
258 /* Return an invalid error to be consistent with epoll. */
260 events
->wait
.nb_fd
= 0;
264 if (events
->need_update
) {
265 ret
= update_current_events(events
);
272 ret
= poll(events
->wait
.events
, events
->wait
.nb_fd
, timeout
);
274 /* At this point, every error is fatal */
280 * poll() should always iterate on all FDs since we handle the pollset in
281 * user space and after poll returns, we have to try every fd for a match.
283 return events
->wait
.nb_fd
;
290 * Setup poll set maximum size.
292 int compat_poll_set_max_size(void)
297 ret
= getrlimit(RLIMIT_NOFILE
, &lim
);
299 PERROR("getrlimit poll RLIMIT_NOFILE");
304 poll_max_size
= lim
.rlim_cur
;
306 if (poll_max_size
== 0) {
307 poll_max_size
= DEFAULT_POLL_SIZE
;
309 DBG("poll set max size set to %u", poll_max_size
);
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