Contents of /trunk/mkinitrd-magellan/busybox/networking/isrv.c
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Sat Sep 1 22:45:15 2007 UTC (17 years ago) by niro
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File size: 7939 byte(s)
Sat Sep 1 22:45:15 2007 UTC (17 years ago) by niro
File MIME type: text/plain
File size: 7939 byte(s)
-import if magellan mkinitrd; it is a fork of redhats mkinitrd-5.0.8 with all magellan patches and features; deprecates magellan-src/mkinitrd
1 | /* vi: set sw=4 ts=4: */ |
2 | /* |
3 | * Generic non-forking server infrastructure. |
4 | * Intended to make writing telnetd-type servers easier. |
5 | * |
6 | * Copyright (C) 2007 Denis Vlasenko |
7 | * |
8 | * Licensed under GPL version 2, see file LICENSE in this tarball for details. |
9 | */ |
10 | |
11 | #include "busybox.h" |
12 | #include "isrv.h" |
13 | |
14 | #define DEBUG 0 |
15 | |
16 | #if DEBUG |
17 | #define DPRINTF(args...) bb_error_msg(args) |
18 | #else |
19 | #define DPRINTF(args...) ((void)0) |
20 | #endif |
21 | |
22 | /* Helpers */ |
23 | |
24 | /* Even if _POSIX_MONOTONIC_CLOCK is defined, this |
25 | * may require librt */ |
26 | #if 0 /*def _POSIX_MONOTONIC_CLOCK*/ |
27 | static time_t monotonic_time(void) |
28 | { |
29 | struct timespec ts; |
30 | if (clock_gettime(CLOCK_MONOTONIC, &ts) != 0) |
31 | time(&ts.tv_sec); |
32 | return ts.tv_sec; |
33 | } |
34 | #else |
35 | #define monotonic_time() (time(NULL)) |
36 | #endif |
37 | |
38 | /* Opaque structure */ |
39 | |
40 | struct isrv_state_t { |
41 | short *fd2peer; /* one per registered fd */ |
42 | void **param_tbl; /* one per registered peer */ |
43 | /* one per registered peer; doesn't exist if !timeout */ |
44 | time_t *timeo_tbl; |
45 | int (*new_peer)(isrv_state_t *state, int fd); |
46 | time_t curtime; |
47 | int timeout; |
48 | int fd_count; |
49 | int peer_count; |
50 | int wr_count; |
51 | fd_set rd; |
52 | fd_set wr; |
53 | }; |
54 | #define FD2PEER (state->fd2peer) |
55 | #define PARAM_TBL (state->param_tbl) |
56 | #define TIMEO_TBL (state->timeo_tbl) |
57 | #define CURTIME (state->curtime) |
58 | #define TIMEOUT (state->timeout) |
59 | #define FD_COUNT (state->fd_count) |
60 | #define PEER_COUNT (state->peer_count) |
61 | #define WR_COUNT (state->wr_count) |
62 | |
63 | /* callback */ |
64 | void isrv_want_rd(isrv_state_t *state, int fd) |
65 | { |
66 | FD_SET(fd, &state->rd); |
67 | } |
68 | |
69 | /* callback */ |
70 | void isrv_want_wr(isrv_state_t *state, int fd) |
71 | { |
72 | if (!FD_ISSET(fd, &state->wr)) { |
73 | WR_COUNT++; |
74 | FD_SET(fd, &state->wr); |
75 | } |
76 | } |
77 | |
78 | /* callback */ |
79 | void isrv_dont_want_rd(isrv_state_t *state, int fd) |
80 | { |
81 | FD_CLR(fd, &state->rd); |
82 | } |
83 | |
84 | /* callback */ |
85 | void isrv_dont_want_wr(isrv_state_t *state, int fd) |
86 | { |
87 | if (FD_ISSET(fd, &state->wr)) { |
88 | WR_COUNT--; |
89 | FD_CLR(fd, &state->wr); |
90 | } |
91 | } |
92 | |
93 | /* callback */ |
94 | int isrv_register_fd(isrv_state_t *state, int peer, int fd) |
95 | { |
96 | int n; |
97 | |
98 | DPRINTF("register_fd(peer:%d,fd:%d)", peer, fd); |
99 | |
100 | if (FD_COUNT >= FD_SETSIZE) return -1; |
101 | if (FD_COUNT <= fd) { |
102 | n = FD_COUNT; |
103 | FD_COUNT = fd + 1; |
104 | |
105 | DPRINTF("register_fd: FD_COUNT %d", FD_COUNT); |
106 | |
107 | FD2PEER = xrealloc(FD2PEER, FD_COUNT * sizeof(FD2PEER[0])); |
108 | while (n < fd) FD2PEER[n++] = -1; |
109 | } |
110 | |
111 | DPRINTF("register_fd: FD2PEER[%d] = %d", fd, peer); |
112 | |
113 | FD2PEER[fd] = peer; |
114 | return 0; |
115 | } |
116 | |
117 | /* callback */ |
118 | void isrv_close_fd(isrv_state_t *state, int fd) |
119 | { |
120 | DPRINTF("close_fd(%d)", fd); |
121 | |
122 | close(fd); |
123 | isrv_dont_want_rd(state, fd); |
124 | if (WR_COUNT) isrv_dont_want_wr(state, fd); |
125 | |
126 | FD2PEER[fd] = -1; |
127 | if (fd == FD_COUNT-1) { |
128 | do fd--; while (fd >= 0 && FD2PEER[fd] == -1); |
129 | FD_COUNT = fd + 1; |
130 | |
131 | DPRINTF("close_fd: FD_COUNT %d", FD_COUNT); |
132 | |
133 | FD2PEER = xrealloc(FD2PEER, FD_COUNT * sizeof(FD2PEER[0])); |
134 | } |
135 | } |
136 | |
137 | /* callback */ |
138 | int isrv_register_peer(isrv_state_t *state, void *param) |
139 | { |
140 | int n; |
141 | |
142 | if (PEER_COUNT >= FD_SETSIZE) return -1; |
143 | n = PEER_COUNT++; |
144 | |
145 | DPRINTF("register_peer: PEER_COUNT %d", PEER_COUNT); |
146 | |
147 | PARAM_TBL = xrealloc(PARAM_TBL, PEER_COUNT * sizeof(PARAM_TBL[0])); |
148 | PARAM_TBL[n] = param; |
149 | if (TIMEOUT) { |
150 | TIMEO_TBL = xrealloc(TIMEO_TBL, PEER_COUNT * sizeof(TIMEO_TBL[0])); |
151 | TIMEO_TBL[n] = CURTIME; |
152 | } |
153 | return n; |
154 | } |
155 | |
156 | static void remove_peer(isrv_state_t *state, int peer) |
157 | { |
158 | int movesize; |
159 | int fd; |
160 | |
161 | DPRINTF("remove_peer(%d)", peer); |
162 | |
163 | fd = FD_COUNT - 1; |
164 | while (fd >= 0) { |
165 | if (FD2PEER[fd] == peer) { |
166 | isrv_close_fd(state, fd); |
167 | fd--; |
168 | continue; |
169 | } |
170 | if (FD2PEER[fd] > peer) |
171 | FD2PEER[fd]--; |
172 | fd--; |
173 | } |
174 | |
175 | PEER_COUNT--; |
176 | DPRINTF("remove_peer: PEER_COUNT %d", PEER_COUNT); |
177 | |
178 | movesize = (PEER_COUNT - peer) * sizeof(void*); |
179 | if (movesize > 0) { |
180 | memcpy(&PARAM_TBL[peer], &PARAM_TBL[peer+1], movesize); |
181 | if (TIMEOUT) |
182 | memcpy(&TIMEO_TBL[peer], &TIMEO_TBL[peer+1], movesize); |
183 | } |
184 | PARAM_TBL = xrealloc(PARAM_TBL, PEER_COUNT * sizeof(PARAM_TBL[0])); |
185 | if (TIMEOUT) |
186 | TIMEO_TBL = xrealloc(TIMEO_TBL, PEER_COUNT * sizeof(TIMEO_TBL[0])); |
187 | } |
188 | |
189 | static void handle_accept(isrv_state_t *state, int fd) |
190 | { |
191 | int n, newfd; |
192 | |
193 | /* suppress gcc warning "cast from ptr to int of different size" */ |
194 | fcntl(fd, F_SETFL, (int)(ptrdiff_t)(PARAM_TBL[0]) | O_NONBLOCK); |
195 | newfd = accept(fd, NULL, 0); |
196 | fcntl(fd, F_SETFL, (int)(ptrdiff_t)(PARAM_TBL[0])); |
197 | if (newfd < 0) { |
198 | if (errno == EAGAIN) return; |
199 | /* Most probably someone gave us wrong fd type |
200 | * (for example, non-socket). Don't want |
201 | * to loop forever. */ |
202 | bb_perror_msg_and_die("accept"); |
203 | } |
204 | |
205 | DPRINTF("new_peer(%d)", newfd); |
206 | n = state->new_peer(state, newfd); |
207 | if (n) |
208 | remove_peer(state, n); /* unsuccesful peer start */ |
209 | } |
210 | |
211 | void BUG_sizeof_fd_set_is_strange(void); |
212 | static void handle_fd_set(isrv_state_t *state, fd_set *fds, int (*h)(int, void **)) |
213 | { |
214 | enum { LONG_CNT = sizeof(fd_set) / sizeof(long) }; |
215 | int fds_pos; |
216 | int fd, peer; |
217 | /* need to know value at _the beginning_ of this routine */ |
218 | int fd_cnt = FD_COUNT; |
219 | |
220 | if (LONG_CNT * sizeof(long) != sizeof(fd_set)) |
221 | BUG_sizeof_fd_set_is_strange(); |
222 | |
223 | fds_pos = 0; |
224 | while (1) { |
225 | /* Find next nonzero bit */ |
226 | while (fds_pos < LONG_CNT) { |
227 | if (((long*)fds)[fds_pos] == 0) { |
228 | fds_pos++; |
229 | continue; |
230 | } |
231 | /* Found non-zero word */ |
232 | fd = fds_pos * sizeof(long)*8; /* word# -> bit# */ |
233 | while (1) { |
234 | if (FD_ISSET(fd, fds)) { |
235 | FD_CLR(fd, fds); |
236 | goto found_fd; |
237 | } |
238 | fd++; |
239 | } |
240 | } |
241 | break; /* all words are zero */ |
242 | found_fd: |
243 | if (fd >= fd_cnt) { /* paranoia */ |
244 | DPRINTF("handle_fd_set: fd > fd_cnt?? (%d > %d)", |
245 | fd, fd_cnt); |
246 | break; |
247 | } |
248 | DPRINTF("handle_fd_set: fd %d is active", fd); |
249 | peer = FD2PEER[fd]; |
250 | if (peer < 0) |
251 | continue; /* peer is already gone */ |
252 | if (peer == 0) { |
253 | handle_accept(state, fd); |
254 | continue; |
255 | } |
256 | DPRINTF("h(fd:%d)", fd); |
257 | if (h(fd, &PARAM_TBL[peer])) { |
258 | /* this peer is gone */ |
259 | remove_peer(state, peer); |
260 | } else if (TIMEOUT) { |
261 | TIMEO_TBL[peer] = monotonic_time(); |
262 | } |
263 | } |
264 | } |
265 | |
266 | static void handle_timeout(isrv_state_t *state, int (*do_timeout)(void **)) |
267 | { |
268 | int n, peer; |
269 | peer = PEER_COUNT-1; |
270 | /* peer 0 is not checked */ |
271 | while (peer > 0) { |
272 | DPRINTF("peer %d: time diff %d", peer, |
273 | (int)(CURTIME - TIMEO_TBL[peer])); |
274 | if ((CURTIME - TIMEO_TBL[peer]) >= TIMEOUT) { |
275 | DPRINTF("peer %d: do_timeout()", peer); |
276 | n = do_timeout(&PARAM_TBL[peer]); |
277 | if (n) |
278 | remove_peer(state, peer); |
279 | } |
280 | peer--; |
281 | } |
282 | } |
283 | |
284 | /* Driver */ |
285 | void isrv_run( |
286 | int listen_fd, |
287 | int (*new_peer)(isrv_state_t *state, int fd), |
288 | int (*do_rd)(int fd, void **), |
289 | int (*do_wr)(int fd, void **), |
290 | int (*do_timeout)(void **), |
291 | int timeout, |
292 | int linger_timeout) |
293 | { |
294 | isrv_state_t *state = xzalloc(sizeof(*state)); |
295 | state->new_peer = new_peer; |
296 | state->timeout = timeout; |
297 | |
298 | /* register "peer" #0 - it will accept new connections */ |
299 | isrv_register_peer(state, NULL); |
300 | isrv_register_fd(state, /*peer:*/ 0, listen_fd); |
301 | isrv_want_rd(state, listen_fd); |
302 | /* remember flags to make blocking<->nonblocking switch faster */ |
303 | /* (suppress gcc warning "cast from ptr to int of different size") */ |
304 | PARAM_TBL[0] = (void*)(ptrdiff_t)(fcntl(listen_fd, F_GETFL, 0)); |
305 | |
306 | while (1) { |
307 | struct timeval tv; |
308 | fd_set rd; |
309 | fd_set wr; |
310 | fd_set *wrp = NULL; |
311 | int n; |
312 | |
313 | tv.tv_sec = timeout; |
314 | if (PEER_COUNT <= 1) |
315 | tv.tv_sec = linger_timeout; |
316 | tv.tv_usec = 0; |
317 | rd = state->rd; |
318 | if (WR_COUNT) { |
319 | wr = state->wr; |
320 | wrp = ≀ |
321 | } |
322 | |
323 | DPRINTF("run: select(FD_COUNT:%d,timeout:%d)...", |
324 | FD_COUNT, (int)tv.tv_sec); |
325 | n = select(FD_COUNT, &rd, wrp, NULL, tv.tv_sec ? &tv : NULL); |
326 | DPRINTF("run: ...select:%d", n); |
327 | |
328 | if (n < 0) { |
329 | if (errno != EINTR) |
330 | bb_perror_msg("select"); |
331 | continue; |
332 | } |
333 | |
334 | if (n == 0 && linger_timeout && PEER_COUNT <= 1) |
335 | break; |
336 | |
337 | if (timeout) { |
338 | time_t t = monotonic_time(); |
339 | if (t != CURTIME) { |
340 | CURTIME = t; |
341 | handle_timeout(state, do_timeout); |
342 | } |
343 | } |
344 | if (n > 0) { |
345 | handle_fd_set(state, &rd, do_rd); |
346 | if (wrp) |
347 | handle_fd_set(state, wrp, do_wr); |
348 | } |
349 | } |
350 | DPRINTF("run: bailout"); |
351 | /* NB: accept socket is not closed. Caller is to decide what to do */ |
352 | } |