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1 | /*- |
2 | * BSD LICENSE | |
3 | * | |
4 | * Copyright(c) 2010-2014 Intel Corporation. All rights reserved. | |
5 | * All rights reserved. | |
6 | * | |
7 | * Redistribution and use in source and binary forms, with or without | |
8 | * modification, are permitted provided that the following conditions | |
9 | * are met: | |
10 | * | |
11 | * * Redistributions of source code must retain the above copyright | |
12 | * notice, this list of conditions and the following disclaimer. | |
13 | * * Redistributions in binary form must reproduce the above copyright | |
14 | * notice, this list of conditions and the following disclaimer in | |
15 | * the documentation and/or other materials provided with the | |
16 | * distribution. | |
17 | * * Neither the name of Intel Corporation nor the names of its | |
18 | * contributors may be used to endorse or promote products derived | |
19 | * from this software without specific prior written permission. | |
20 | * | |
21 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
22 | * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
23 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR | |
24 | * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT | |
25 | * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | |
26 | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT | |
27 | * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
28 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
29 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
30 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | |
31 | * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
32 | */ | |
33 | ||
34 | #include <stdint.h> | |
35 | #include <stdio.h> | |
36 | #include <stdlib.h> | |
37 | #include <sys/socket.h> | |
38 | #include <sys/select.h> | |
39 | #include <sys/time.h> | |
40 | #include <sys/types.h> | |
41 | #include <unistd.h> | |
42 | ||
43 | #include <rte_common.h> | |
44 | #include <rte_log.h> | |
45 | ||
46 | #include "fd_man.h" | |
47 | ||
48 | /** | |
49 | * Returns the index in the fdset for a given fd. | |
50 | * If fd is -1, it means to search for a free entry. | |
51 | * @return | |
52 | * index for the fd, or -1 if fd isn't in the fdset. | |
53 | */ | |
54 | static int | |
55 | fdset_find_fd(struct fdset *pfdset, int fd) | |
56 | { | |
57 | int i; | |
58 | ||
59 | if (pfdset == NULL) | |
60 | return -1; | |
61 | ||
62 | for (i = 0; i < MAX_FDS && pfdset->fd[i].fd != fd; i++) | |
63 | ; | |
64 | ||
65 | return i == MAX_FDS ? -1 : i; | |
66 | } | |
67 | ||
68 | static int | |
69 | fdset_find_free_slot(struct fdset *pfdset) | |
70 | { | |
71 | return fdset_find_fd(pfdset, -1); | |
72 | } | |
73 | ||
74 | static int | |
75 | fdset_add_fd(struct fdset *pfdset, int idx, int fd, | |
76 | fd_cb rcb, fd_cb wcb, void *dat) | |
77 | { | |
78 | struct fdentry *pfdentry; | |
79 | ||
80 | if (pfdset == NULL || idx >= MAX_FDS || fd >= FD_SETSIZE) | |
81 | return -1; | |
82 | ||
83 | pfdentry = &pfdset->fd[idx]; | |
84 | pfdentry->fd = fd; | |
85 | pfdentry->rcb = rcb; | |
86 | pfdentry->wcb = wcb; | |
87 | pfdentry->dat = dat; | |
88 | ||
89 | return 0; | |
90 | } | |
91 | ||
92 | /** | |
93 | * Fill the read/write fd_set with the fds in the fdset. | |
94 | * @return | |
95 | * the maximum fds filled in the read/write fd_set. | |
96 | */ | |
97 | static int | |
98 | fdset_fill(fd_set *rfset, fd_set *wfset, struct fdset *pfdset) | |
99 | { | |
100 | struct fdentry *pfdentry; | |
101 | int i, maxfds = -1; | |
102 | int num = MAX_FDS; | |
103 | ||
104 | if (pfdset == NULL) | |
105 | return -1; | |
106 | ||
107 | for (i = 0; i < num; i++) { | |
108 | pfdentry = &pfdset->fd[i]; | |
109 | if (pfdentry->fd != -1) { | |
110 | int added = 0; | |
111 | if (pfdentry->rcb && rfset) { | |
112 | FD_SET(pfdentry->fd, rfset); | |
113 | added = 1; | |
114 | } | |
115 | if (pfdentry->wcb && wfset) { | |
116 | FD_SET(pfdentry->fd, wfset); | |
117 | added = 1; | |
118 | } | |
119 | if (added) | |
120 | maxfds = pfdentry->fd < maxfds ? | |
121 | maxfds : pfdentry->fd; | |
122 | } | |
123 | } | |
124 | return maxfds; | |
125 | } | |
126 | ||
127 | void | |
128 | fdset_init(struct fdset *pfdset) | |
129 | { | |
130 | int i; | |
131 | ||
132 | if (pfdset == NULL) | |
133 | return; | |
134 | ||
135 | for (i = 0; i < MAX_FDS; i++) { | |
136 | pfdset->fd[i].fd = -1; | |
137 | pfdset->fd[i].dat = NULL; | |
138 | } | |
139 | pfdset->num = 0; | |
140 | } | |
141 | ||
142 | /** | |
143 | * Register the fd in the fdset with read/write handler and context. | |
144 | */ | |
145 | int | |
146 | fdset_add(struct fdset *pfdset, int fd, fd_cb rcb, fd_cb wcb, void *dat) | |
147 | { | |
148 | int i; | |
149 | ||
150 | if (pfdset == NULL || fd == -1) | |
151 | return -1; | |
152 | ||
153 | pthread_mutex_lock(&pfdset->fd_mutex); | |
154 | ||
155 | /* Find a free slot in the list. */ | |
156 | i = fdset_find_free_slot(pfdset); | |
157 | if (i == -1 || fdset_add_fd(pfdset, i, fd, rcb, wcb, dat) < 0) { | |
158 | pthread_mutex_unlock(&pfdset->fd_mutex); | |
159 | return -2; | |
160 | } | |
161 | ||
162 | pfdset->num++; | |
163 | ||
164 | pthread_mutex_unlock(&pfdset->fd_mutex); | |
165 | ||
166 | return 0; | |
167 | } | |
168 | ||
169 | /** | |
170 | * Unregister the fd from the fdset. | |
171 | * Returns context of a given fd or NULL. | |
172 | */ | |
173 | void * | |
174 | fdset_del(struct fdset *pfdset, int fd) | |
175 | { | |
176 | int i; | |
177 | void *dat = NULL; | |
178 | ||
179 | if (pfdset == NULL || fd == -1) | |
180 | return NULL; | |
181 | ||
182 | do { | |
183 | pthread_mutex_lock(&pfdset->fd_mutex); | |
184 | ||
185 | i = fdset_find_fd(pfdset, fd); | |
186 | if (i != -1 && pfdset->fd[i].busy == 0) { | |
187 | /* busy indicates r/wcb is executing! */ | |
188 | dat = pfdset->fd[i].dat; | |
189 | pfdset->fd[i].fd = -1; | |
190 | pfdset->fd[i].rcb = pfdset->fd[i].wcb = NULL; | |
191 | pfdset->fd[i].dat = NULL; | |
192 | pfdset->num--; | |
193 | i = -1; | |
194 | } | |
195 | pthread_mutex_unlock(&pfdset->fd_mutex); | |
196 | } while (i != -1); | |
197 | ||
198 | return dat; | |
199 | } | |
200 | ||
201 | /** | |
202 | * Unregister the fd at the specified slot from the fdset. | |
203 | */ | |
204 | static void | |
205 | fdset_del_slot(struct fdset *pfdset, int index) | |
206 | { | |
207 | if (pfdset == NULL || index < 0 || index >= MAX_FDS) | |
208 | return; | |
209 | ||
210 | pthread_mutex_lock(&pfdset->fd_mutex); | |
211 | ||
212 | pfdset->fd[index].fd = -1; | |
213 | pfdset->fd[index].rcb = pfdset->fd[index].wcb = NULL; | |
214 | pfdset->fd[index].dat = NULL; | |
215 | pfdset->num--; | |
216 | ||
217 | pthread_mutex_unlock(&pfdset->fd_mutex); | |
218 | } | |
219 | ||
220 | /** | |
221 | * This functions runs in infinite blocking loop until there is no fd in | |
222 | * pfdset. It calls corresponding r/w handler if there is event on the fd. | |
223 | * | |
224 | * Before the callback is called, we set the flag to busy status; If other | |
225 | * thread(now rte_vhost_driver_unregister) calls fdset_del concurrently, it | |
226 | * will wait until the flag is reset to zero(which indicates the callback is | |
227 | * finished), then it could free the context after fdset_del. | |
228 | */ | |
229 | void | |
230 | fdset_event_dispatch(struct fdset *pfdset) | |
231 | { | |
232 | fd_set rfds, wfds; | |
233 | int i, maxfds; | |
234 | struct fdentry *pfdentry; | |
235 | int num = MAX_FDS; | |
236 | fd_cb rcb, wcb; | |
237 | void *dat; | |
238 | int fd; | |
239 | int remove1, remove2; | |
240 | int ret; | |
241 | ||
242 | if (pfdset == NULL) | |
243 | return; | |
244 | ||
245 | while (1) { | |
246 | struct timeval tv; | |
247 | tv.tv_sec = 1; | |
248 | tv.tv_usec = 0; | |
249 | FD_ZERO(&rfds); | |
250 | FD_ZERO(&wfds); | |
251 | pthread_mutex_lock(&pfdset->fd_mutex); | |
252 | ||
253 | maxfds = fdset_fill(&rfds, &wfds, pfdset); | |
254 | ||
255 | pthread_mutex_unlock(&pfdset->fd_mutex); | |
256 | ||
257 | /* | |
258 | * When select is blocked, other threads might unregister | |
259 | * listenfds from and register new listenfds into fdset. | |
260 | * When select returns, the entries for listenfds in the fdset | |
261 | * might have been updated. It is ok if there is unwanted call | |
262 | * for new listenfds. | |
263 | */ | |
264 | ret = select(maxfds + 1, &rfds, &wfds, NULL, &tv); | |
265 | if (ret <= 0) | |
266 | continue; | |
267 | ||
268 | for (i = 0; i < num; i++) { | |
269 | remove1 = remove2 = 0; | |
270 | pthread_mutex_lock(&pfdset->fd_mutex); | |
271 | pfdentry = &pfdset->fd[i]; | |
272 | fd = pfdentry->fd; | |
273 | rcb = pfdentry->rcb; | |
274 | wcb = pfdentry->wcb; | |
275 | dat = pfdentry->dat; | |
276 | pfdentry->busy = 1; | |
277 | pthread_mutex_unlock(&pfdset->fd_mutex); | |
278 | if (fd >= 0 && FD_ISSET(fd, &rfds) && rcb) | |
279 | rcb(fd, dat, &remove1); | |
280 | if (fd >= 0 && FD_ISSET(fd, &wfds) && wcb) | |
281 | wcb(fd, dat, &remove2); | |
282 | pfdentry->busy = 0; | |
283 | /* | |
284 | * fdset_del needs to check busy flag. | |
285 | * We don't allow fdset_del to be called in callback | |
286 | * directly. | |
287 | */ | |
288 | /* | |
289 | * When we are to clean up the fd from fdset, | |
290 | * because the fd is closed in the cb, | |
291 | * the old fd val could be reused by when creates new | |
292 | * listen fd in another thread, we couldn't call | |
293 | * fd_set_del. | |
294 | */ | |
295 | if (remove1 || remove2) | |
296 | fdset_del_slot(pfdset, i); | |
297 | } | |
298 | } | |
299 | } |