| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * I/O multiplexing support |
| 4 | * |
| 5 | * (c) 1999 Straylight/Edgeware |
| 6 | */ |
| 7 | |
| 8 | /*----- Licensing notice --------------------------------------------------* |
| 9 | * |
| 10 | * This file is part of the mLib utilities library. |
| 11 | * |
| 12 | * mLib is free software; you can redistribute it and/or modify |
| 13 | * it under the terms of the GNU Library General Public License as |
| 14 | * published by the Free Software Foundation; either version 2 of the |
| 15 | * License, or (at your option) any later version. |
| 16 | * |
| 17 | * mLib is distributed in the hope that it will be useful, |
| 18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 20 | * GNU Library General Public License for more details. |
| 21 | * |
| 22 | * You should have received a copy of the GNU Library General Public |
| 23 | * License along with mLib; if not, write to the Free |
| 24 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
| 25 | * MA 02111-1307, USA. |
| 26 | */ |
| 27 | |
| 28 | /*----- Header files ------------------------------------------------------*/ |
| 29 | |
| 30 | #include <assert.h> |
| 31 | #include <stdio.h> |
| 32 | #include <stdlib.h> |
| 33 | #include <string.h> |
| 34 | |
| 35 | #include <sys/types.h> |
| 36 | #include <sys/time.h> |
| 37 | #include <unistd.h> |
| 38 | |
| 39 | #include "sel.h" |
| 40 | #include "sub.h" |
| 41 | #include "tv.h" |
| 42 | |
| 43 | /*----- Data structures ---------------------------------------------------*/ |
| 44 | |
| 45 | typedef struct sel_pendfile { |
| 46 | struct sel_pendfile *next; |
| 47 | sel_file *f; |
| 48 | } pfile; |
| 49 | |
| 50 | typedef struct sel_pendtimer { |
| 51 | struct sel_pendtimer *next; |
| 52 | sel_timer *t; |
| 53 | } ptimer; |
| 54 | |
| 55 | /*----- Main code ---------------------------------------------------------*/ |
| 56 | |
| 57 | /* --- @sel_init@ --- * |
| 58 | * |
| 59 | * Arguments: @sel_state *s@ = pointer to a state block to initialize |
| 60 | * |
| 61 | * Returns: --- |
| 62 | * |
| 63 | * Use: Initializes a select state block. |
| 64 | */ |
| 65 | |
| 66 | void sel_init(sel_state *s) |
| 67 | { |
| 68 | int i; |
| 69 | |
| 70 | for (i = 0; i < SEL_MODES; i++) { |
| 71 | s->files[i] = 0; |
| 72 | FD_ZERO(&s->fd[i]); |
| 73 | } |
| 74 | s->timers = 0; |
| 75 | s->hooks = 0; |
| 76 | s->args = 0; |
| 77 | } |
| 78 | |
| 79 | /* --- @sel_initfile@ --- * |
| 80 | * |
| 81 | * Arguments: @sel_state *s@ = select state to attach to |
| 82 | * @sel_file *f@ = pointer to a file block to initialize |
| 83 | * @int fd@ = the file descriptor to listen to |
| 84 | * @unsigned mode@ = what to listen for |
| 85 | * @void (*func)(int fd, unsigned mode, void *p)@ = handler |
| 86 | * @void *p@ = argument to pass to handler |
| 87 | * |
| 88 | * Returns: --- |
| 89 | * |
| 90 | * Use: Initializes a file block ready for use. The file block |
| 91 | * isn't added to the list of things to do until a call to |
| 92 | * @sel_addfile@. |
| 93 | */ |
| 94 | |
| 95 | void sel_initfile(sel_state *s, sel_file *f, |
| 96 | int fd, unsigned mode, |
| 97 | void (*func)(int /*fd*/, unsigned /*mode*/, void */*p*/), |
| 98 | void *p) |
| 99 | { |
| 100 | f->s = s; |
| 101 | f->fd = fd; |
| 102 | f->mode = mode; |
| 103 | f->func = func; |
| 104 | f->p = p; |
| 105 | f->pend = 0; |
| 106 | } |
| 107 | |
| 108 | /* --- @sel_addfile@ --- * |
| 109 | * |
| 110 | * Arguments: @sel_file *f@ = pointer to a file block |
| 111 | * |
| 112 | * Returns: --- |
| 113 | * |
| 114 | * Use: Adds a file block into the list of things to listen to. |
| 115 | */ |
| 116 | |
| 117 | void sel_addfile(sel_file *f) |
| 118 | { |
| 119 | sel_file **ff = &f->s->files[f->mode]; |
| 120 | |
| 121 | /* --- This little dance looks like line-noise, but it does the job --- */ |
| 122 | |
| 123 | while (*ff && (*ff)->fd > f->fd) |
| 124 | ff = &(*ff)->next; |
| 125 | f->next = *ff; |
| 126 | f->prev = ff; |
| 127 | if (*ff) |
| 128 | (*ff)->prev = &f->next; |
| 129 | *ff = f; |
| 130 | FD_SET(f->fd, f->s->fd + f->mode); |
| 131 | } |
| 132 | |
| 133 | /* --- @sel_force@ --- * |
| 134 | * |
| 135 | * Arguments: @sel_file *f@ = pointer to file selector |
| 136 | * |
| 137 | * Returns: --- |
| 138 | * |
| 139 | * Use: Forces a file selector to be considered ready. This is only |
| 140 | * useful during a call to @sel_select@. Of particular use is |
| 141 | * forcing a write selector when there's something interesting |
| 142 | * ready for it. |
| 143 | */ |
| 144 | |
| 145 | void sel_force(sel_file *f) |
| 146 | { |
| 147 | if (f->s->args) |
| 148 | FD_SET(f->fd, &f->s->args->fd[f->mode]); |
| 149 | } |
| 150 | |
| 151 | /* --- @sel_rmfile@ --- * |
| 152 | * |
| 153 | * Arguments: @sel_file *f@ = pointer to a file block |
| 154 | * |
| 155 | * Returns: --- |
| 156 | * |
| 157 | * Use: Removes a file block from the list of things to listen to. |
| 158 | */ |
| 159 | |
| 160 | void sel_rmfile(sel_file *f) |
| 161 | { |
| 162 | *f->prev = f->next; |
| 163 | if (f->next) |
| 164 | f->next->prev = f->prev; |
| 165 | FD_CLR(f->fd, f->s->fd + f->mode); |
| 166 | if (f->pend) { |
| 167 | f->pend->f = 0; |
| 168 | f->pend = 0; |
| 169 | } |
| 170 | } |
| 171 | |
| 172 | /* --- @sel_addtimer@ --- * |
| 173 | * |
| 174 | * Arguments: @sel_state *s@ = pointer to a state block |
| 175 | * @sel_timer *t@ = pointer to a timer block |
| 176 | * @struct timeval *tv@ = pointer to time to activate |
| 177 | * @void (*func)(struct timeval *tv, void *p)@ = handler |
| 178 | * @void *p@ = argument for handler function |
| 179 | * |
| 180 | * Returns: --- |
| 181 | * |
| 182 | * Use: Registers and sets up a timer. |
| 183 | */ |
| 184 | |
| 185 | void sel_addtimer(sel_state *s, sel_timer *t, |
| 186 | struct timeval *tv, |
| 187 | void (*func)(struct timeval */*tv*/, void */*p*/), |
| 188 | void *p) |
| 189 | { |
| 190 | sel_timer **tt = &s->timers; |
| 191 | { sel_timer *q; for (q = s->timers; q; q = q->next) assert(q != t); } |
| 192 | |
| 193 | /* --- Set up the timer block --- */ |
| 194 | |
| 195 | t->tv = *tv; |
| 196 | t->func = func; |
| 197 | t->p = p; |
| 198 | t->pend = 0; |
| 199 | |
| 200 | /* --- More line noise --- */ |
| 201 | |
| 202 | while (*tt && TV_CMP(&(*tt)->tv, <, tv)) |
| 203 | tt = &(*tt)->next; |
| 204 | t->next = *tt; |
| 205 | t->prev = tt; |
| 206 | if (*tt) |
| 207 | (*tt)->prev = &t->next; |
| 208 | *tt = t; |
| 209 | } |
| 210 | |
| 211 | /* --- @sel_rmtimer@ --- * |
| 212 | * |
| 213 | * Arguments: @sel_timer *t@ = pointer to timer block |
| 214 | * |
| 215 | * Returns: --- |
| 216 | * |
| 217 | * Use: Removes a timer from the list of timers. |
| 218 | */ |
| 219 | |
| 220 | void sel_rmtimer(sel_timer *t) |
| 221 | { |
| 222 | if (t->pend) { |
| 223 | t->pend->t = 0; |
| 224 | t->pend = 0; |
| 225 | } else { |
| 226 | *t->prev = t->next; |
| 227 | if (t->next) |
| 228 | t->next->prev = t->prev; |
| 229 | } |
| 230 | } |
| 231 | |
| 232 | /* --- @sel_addhook@ --- * |
| 233 | * |
| 234 | * Arguments: @sel_state *s@ = pointer to state block |
| 235 | * @sel_hook *h@ = pointer to hook block |
| 236 | * @sel_hookfn before, after@ = hook functions |
| 237 | * @void *p@ = pointer argument to pass to hook functions |
| 238 | * |
| 239 | * Returns: --- |
| 240 | * |
| 241 | * Use: Registers hook functions to be called on each select call. |
| 242 | */ |
| 243 | |
| 244 | void sel_addhook(sel_state *s, sel_hook *h, |
| 245 | sel_hookfn before, sel_hookfn after, |
| 246 | void *p) |
| 247 | { |
| 248 | h->before = before; |
| 249 | h->after = after; |
| 250 | h->p = p; |
| 251 | h->next = s->hooks; |
| 252 | h->prev = &s->hooks; |
| 253 | if (s->hooks) |
| 254 | s->hooks->prev = &h->next; |
| 255 | s->hooks = h; |
| 256 | } |
| 257 | |
| 258 | /* --- @sel_rmhook@ --- * |
| 259 | * |
| 260 | * Arguments: @sel_hook *h@ = pointer to hook block |
| 261 | * |
| 262 | * Returns: --- |
| 263 | * |
| 264 | * Use: Removes hook functions. |
| 265 | */ |
| 266 | |
| 267 | void sel_rmhook(sel_hook *h) |
| 268 | { |
| 269 | if (h->next) |
| 270 | h->next->prev = h->prev; |
| 271 | *h->prev = h->next; |
| 272 | } |
| 273 | |
| 274 | /* --- @sel_fdmerge@ --- * |
| 275 | * |
| 276 | * Arguments: @fd_set *dest@ = destination FD set |
| 277 | * @fd_set *fd@ = pointer to set to merge |
| 278 | * @int maxfd@ = highest numbered descriptor in @fd@ + 1 |
| 279 | * |
| 280 | * Returns: Actual highest numbered descriptor. |
| 281 | * |
| 282 | * Use: Merges file descriptor sets, and returns an accurate @maxfd@ |
| 283 | * value. |
| 284 | */ |
| 285 | |
| 286 | int sel_fdmerge(fd_set *dest, fd_set *fd, int maxfd) |
| 287 | { |
| 288 | int i, m = -1; |
| 289 | |
| 290 | for (i = 0; i < maxfd; i++) { |
| 291 | if (FD_ISSET(i, fd)) { |
| 292 | FD_SET(i, dest); |
| 293 | m = i; |
| 294 | } |
| 295 | } |
| 296 | |
| 297 | return (m + 1); |
| 298 | } |
| 299 | |
| 300 | /* --- @sel_select@ --- * |
| 301 | * |
| 302 | * Arguments: @sel_state *s@ = pointer to state block |
| 303 | * |
| 304 | * Returns: Zero if all OK, -1 on error. |
| 305 | * |
| 306 | * Use: Does a @select@ call (or equivalent @poll@). |
| 307 | */ |
| 308 | |
| 309 | int sel_select(sel_state *s) |
| 310 | { |
| 311 | sel_args a; |
| 312 | int err; |
| 313 | |
| 314 | /* --- Initialize the argument block --- */ |
| 315 | |
| 316 | { |
| 317 | int i; |
| 318 | a.maxfd = 0; |
| 319 | for (i = 0; i < SEL_MODES; i++) { |
| 320 | if (s->files[i] && s->files[i]->fd >= a.maxfd) |
| 321 | a.maxfd = s->files[i]->fd + 1; |
| 322 | } |
| 323 | } |
| 324 | |
| 325 | memcpy(a.fd, s->fd, sizeof(a.fd)); |
| 326 | if (s->timers || s->hooks) |
| 327 | gettimeofday(&a.now, 0); |
| 328 | if (!s->timers) |
| 329 | a.tvp = 0; |
| 330 | else { |
| 331 | if (TV_CMP(&s->timers->tv, >, &a.now)) |
| 332 | TV_SUB(&a.tv, &s->timers->tv, &a.now); |
| 333 | else { |
| 334 | a.tv.tv_sec = 0; |
| 335 | a.tv.tv_usec = 0; |
| 336 | } |
| 337 | a.tvp = &a.tv; |
| 338 | } |
| 339 | s->args = &a; |
| 340 | |
| 341 | /* --- Grind through the pre hooks --- */ |
| 342 | |
| 343 | { |
| 344 | sel_hook *h = s->hooks; |
| 345 | while (h) { |
| 346 | sel_hook *hh = h; |
| 347 | h = h->next; |
| 348 | if (hh->before) |
| 349 | hh->before(s, &a, hh->p); |
| 350 | } |
| 351 | } |
| 352 | |
| 353 | /* --- Run the @select@ call --- */ |
| 354 | |
| 355 | if ((err = select(a.maxfd, |
| 356 | &a.fd[SEL_READ], &a.fd[SEL_WRITE], &a.fd[SEL_EXC], |
| 357 | a.tvp)) < 0) { |
| 358 | s->args = 0; |
| 359 | return (err); |
| 360 | } |
| 361 | |
| 362 | if (a.tvp) |
| 363 | gettimeofday(&a.now, 0); |
| 364 | |
| 365 | /* --- Run through the hooks again --- */ |
| 366 | |
| 367 | { |
| 368 | sel_hook *h = s->hooks; |
| 369 | while (h) { |
| 370 | sel_hook *hh = h; |
| 371 | h = h->next; |
| 372 | if (hh->after) |
| 373 | hh->after(s, &a, hh->p); |
| 374 | } |
| 375 | } |
| 376 | |
| 377 | /* --- Run through the timers --- */ |
| 378 | |
| 379 | if (s->timers) { |
| 380 | ptimer *pthead, *pt, **ptt = &pthead; |
| 381 | sel_timer *t; |
| 382 | |
| 383 | for (t = s->timers; t && TV_CMP(&t->tv, <=, &a.now); t = t->next) { |
| 384 | pt = CREATE(ptimer); |
| 385 | pt->t = t; |
| 386 | t->pend = pt; |
| 387 | *ptt = pt; |
| 388 | ptt = &pt->next; |
| 389 | } |
| 390 | *ptt = 0; |
| 391 | if (t) { |
| 392 | *t->prev = 0; |
| 393 | t->prev = &s->timers; |
| 394 | } |
| 395 | s->timers = t; |
| 396 | while (pthead) { |
| 397 | pt = pthead; |
| 398 | pthead = pt->next; |
| 399 | t = pt->t; |
| 400 | if (t) { |
| 401 | t->pend = 0; |
| 402 | t->next = 0; |
| 403 | t->prev = &t->next; |
| 404 | t->func(&a.now, t->p); |
| 405 | } |
| 406 | DESTROY(pt); |
| 407 | } |
| 408 | } |
| 409 | |
| 410 | /* --- And finally run through the files --- * |
| 411 | * |
| 412 | * Do reads first. It's quite possible that a read might prompt a write, |
| 413 | * but the other way around is less likely. Fortunately, the modes are |
| 414 | * in the right order for this. |
| 415 | */ |
| 416 | |
| 417 | { |
| 418 | int i; |
| 419 | |
| 420 | for (i = 0; i < SEL_MODES; i++) { |
| 421 | pfile *pfhead, *pf, **pff = &pfhead; |
| 422 | sel_file *f; |
| 423 | |
| 424 | for (f = s->files[i]; f; f = f->next) { |
| 425 | if (!FD_ISSET(f->fd, &a.fd[i])) |
| 426 | continue; |
| 427 | pf = CREATE(pfile); |
| 428 | pf->f = f; |
| 429 | f->pend = pf; |
| 430 | *pff = pf; |
| 431 | pff = &pf->next; |
| 432 | } |
| 433 | *pff = 0; |
| 434 | while (pfhead) { |
| 435 | pf = pfhead; |
| 436 | pfhead = pf->next; |
| 437 | f = pf->f; |
| 438 | if (f) { |
| 439 | f->pend = 0; |
| 440 | f->func(f->fd, i, f->p); |
| 441 | } |
| 442 | DESTROY(pf); |
| 443 | } |
| 444 | } |
| 445 | } |
| 446 | |
| 447 | s->args = 0; |
| 448 | return (0); |
| 449 | } |
| 450 | |
| 451 | /*----- That's all, folks -------------------------------------------------*/ |