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.
21 #include <sys/resource.h>
24 #include <common/defaults.h>
25 #include <common/error.h>
29 unsigned int poll_max_size
;
32 * Resize the epoll events structure of the new size.
34 * Return 0 on success or else -1 with the current events pointer untouched.
36 static int resize_poll_event(struct compat_poll_event_array
*array
,
43 ptr
= realloc(array
->events
, new_size
* sizeof(*ptr
));
45 PERROR("realloc epoll add");
49 array
->alloc_size
= new_size
;
58 * Update events with the current events object.
60 static int update_current_events(struct lttng_poll_event
*events
)
63 struct compat_poll_event_array
*current
, *wait
;
67 current
= &events
->current
;
70 wait
->nb_fd
= current
->nb_fd
;
71 if (events
->need_realloc
) {
72 ret
= resize_poll_event(wait
, current
->alloc_size
);
77 memcpy(wait
->events
, current
->events
,
78 current
->nb_fd
* sizeof(*current
->events
));
80 /* Update is done and realloc as well. */
81 events
->need_update
= 0;
82 events
->need_realloc
= 0;
91 * Create pollfd data structure.
93 int compat_poll_create(struct lttng_poll_event
*events
, int size
)
95 struct compat_poll_event_array
*current
, *wait
;
97 if (events
== NULL
|| size
<= 0) {
98 ERR("Wrong arguments for poll create");
102 /* Don't bust the limit here */
103 if (size
> poll_max_size
) {
104 size
= poll_max_size
;
107 /* Reset everything before begining the allocation. */
108 memset(events
, 0, sizeof(struct lttng_poll_event
));
110 /* Ease our life a bit. */
111 current
= &events
->current
;
112 wait
= &events
->wait
;
114 /* This *must* be freed by using lttng_poll_free() */
115 wait
->events
= zmalloc(size
* sizeof(struct pollfd
));
116 if (wait
->events
== NULL
) {
117 perror("zmalloc struct pollfd");
121 wait
->alloc_size
= wait
->init_size
= size
;
123 current
->events
= zmalloc(size
* sizeof(struct pollfd
));
124 if (current
->events
== NULL
) {
125 perror("zmalloc struct current pollfd");
129 current
->alloc_size
= current
->init_size
= size
;
138 * Add fd to pollfd data structure with requested events.
140 int compat_poll_add(struct lttng_poll_event
*events
, int fd
,
143 int new_size
, ret
, i
;
144 struct compat_poll_event_array
*current
;
146 if (events
== NULL
|| events
->current
.events
== NULL
|| fd
< 0) {
147 ERR("Bad compat poll add arguments");
151 /* Ease our life a bit. */
152 current
= &events
->current
;
154 /* Check if fd we are trying to add is already there. */
155 for (i
= 0; i
< current
->nb_fd
; i
++) {
156 /* Don't put back the fd we want to delete */
157 if (current
->events
[i
].fd
== fd
) {
163 /* Check for a needed resize of the array. */
164 if (current
->nb_fd
> current
->alloc_size
) {
165 /* Expand it by a power of two of the current size. */
166 new_size
= current
->alloc_size
<< 1UL;
167 ret
= resize_poll_event(current
, new_size
);
171 events
->need_realloc
= 1;
174 current
->events
[current
->nb_fd
].fd
= fd
;
175 current
->events
[current
->nb_fd
].events
= req_events
;
177 events
->need_update
= 1;
179 DBG("fd %d of %d added to pollfd", fd
, current
->nb_fd
);
188 * Remove a fd from the pollfd structure.
190 int compat_poll_del(struct lttng_poll_event
*events
, int fd
)
192 int new_size
, i
, count
= 0, ret
;
193 struct compat_poll_event_array
*current
;
195 if (events
== NULL
|| events
->current
.events
== NULL
|| fd
< 0) {
196 ERR("Wrong arguments for poll del");
200 /* Ease our life a bit. */
201 current
= &events
->current
;
203 /* Safety check on size */
204 if (new_size
> poll_max_size
) {
205 new_size
= poll_max_size
;
208 /* Check if we need to shrink it down. */
209 if ((current
->nb_fd
<< 1UL) <= current
->alloc_size
&&
210 current
->nb_fd
>= current
->init_size
) {
212 * Shrink if nb_fd multiplied by two is <= than the actual size and we
213 * are above the initial size.
215 new_size
= current
->alloc_size
>> 1UL;
216 ret
= resize_poll_event(current
, new_size
);
220 events
->need_realloc
= 1;
223 for (i
= 0; i
< current
->nb_fd
; i
++) {
224 /* Don't put back the fd we want to delete */
225 if (current
->events
[i
].fd
!= fd
) {
226 current
->events
[count
].fd
= current
->events
[i
].fd
;
227 current
->events
[count
].events
= current
->events
[i
].events
;
233 events
->need_update
= 1;
242 * Wait on poll() with timeout. Blocking call.
244 int compat_poll_wait(struct lttng_poll_event
*events
, int timeout
)
248 if (events
== NULL
|| events
->current
.events
== NULL
) {
249 ERR("poll wait arguments error");
253 if (events
->current
.nb_fd
== 0) {
254 /* Return an invalid error to be consistent with epoll. */
259 if (events
->need_update
) {
260 ret
= update_current_events(events
);
267 ret
= poll(events
->wait
.events
, events
->wait
.nb_fd
, timeout
);
269 /* At this point, every error is fatal */
275 * poll() should always iterate on all FDs since we handle the pollset in
276 * user space and after poll returns, we have to try every fd for a match.
278 return events
->wait
.nb_fd
;
285 * Setup poll set maximum size.
287 void compat_poll_set_max_size(void)
293 poll_max_size
= DEFAULT_POLL_SIZE
;
295 ret
= getrlimit(RLIMIT_NOFILE
, &lim
);
297 perror("getrlimit poll RLIMIT_NOFILE");
301 poll_max_size
= lim
.rlim_cur
;
302 if (poll_max_size
== 0) {
303 /* Extra precaution */
304 poll_max_size
= DEFAULT_POLL_SIZE
;
307 DBG("poll set max size set to %u", poll_max_size
);
This page took 0.038224 seconds and 5 git commands to generate.