| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * Operations on SysV semaphores |
| 4 | * |
| 5 | * (c) 2016 Mark Wooding |
| 6 | */ |
| 7 | |
| 8 | /*----- Licensing notice --------------------------------------------------* |
| 9 | * |
| 10 | * This program is free software; you can redistribute it and/or modify |
| 11 | * it under the terms of the GNU General Public License as published by |
| 12 | * the Free Software Foundation; either version 2 of the License, or |
| 13 | * (at your option) any later version. |
| 14 | * |
| 15 | * This program is distributed in the hope that it will be useful, |
| 16 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 18 | * GNU General Public License for more details. |
| 19 | * |
| 20 | * You should have received a copy of the GNU General Public License |
| 21 | * along with this program; if not, write to the Free Software Foundation, |
| 22 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 23 | */ |
| 24 | |
| 25 | /*----- Header files ------------------------------------------------------*/ |
| 26 | |
| 27 | #include <assert.h> |
| 28 | #include <ctype.h> |
| 29 | #include <errno.h> |
| 30 | #include <float.h> |
| 31 | #include <limits.h> |
| 32 | #include <signal.h> |
| 33 | #include <stdio.h> |
| 34 | #include <stdlib.h> |
| 35 | #include <string.h> |
| 36 | #include <time.h> |
| 37 | |
| 38 | #include <sys/types.h> |
| 39 | #include <sys/ipc.h> |
| 40 | #include <sys/sem.h> |
| 41 | |
| 42 | #include <unistd.h> |
| 43 | #include <fcntl.h> |
| 44 | #include <sys/stat.h> |
| 45 | #include <sys/wait.h> |
| 46 | |
| 47 | #include <mLib/mdwopt.h> |
| 48 | #include <mLib/quis.h> |
| 49 | #include <mLib/report.h> |
| 50 | #include <mLib/tv.h> |
| 51 | |
| 52 | #include "fence.h" |
| 53 | #include "timemax.h" |
| 54 | |
| 55 | /* Oh, for pity's sake why did nobody do this for us? */ |
| 56 | union semun { |
| 57 | int val; |
| 58 | struct semid_ds *buf; |
| 59 | unsigned short *array; |
| 60 | }; |
| 61 | |
| 62 | /*----- Random utilities --------------------------------------------------*/ |
| 63 | |
| 64 | static int parse_int(const char *what, const char *p, |
| 65 | int radix, int min, int max) |
| 66 | { |
| 67 | char *q; |
| 68 | int oerr; |
| 69 | long i = -1; |
| 70 | |
| 71 | oerr = errno; |
| 72 | if (isspace((unsigned char)*p)) errno = EINVAL; |
| 73 | else i = strtol(p, &q, radix); |
| 74 | if (*q || errno || !(min <= i && i <= max)) |
| 75 | die(253, "invalid %s `%s'", what, p); |
| 76 | errno = oerr; |
| 77 | return ((int)i); |
| 78 | } |
| 79 | |
| 80 | /*----- Timeout handling --------------------------------------------------*/ |
| 81 | |
| 82 | enum { NEVER, UNTIL, FOREVER }; |
| 83 | |
| 84 | struct timeout { |
| 85 | int wait; |
| 86 | struct timeval tv; |
| 87 | }; |
| 88 | |
| 89 | static struct timeval now; |
| 90 | |
| 91 | static void update_now(void) { int rc = gettimeofday(&now, 0); assert(!rc); } |
| 92 | |
| 93 | static void f2tv(double t, struct timeval *tv) |
| 94 | { tv->tv_sec = t; tv->tv_usec = 1e6*(t - tv->tv_sec); } |
| 95 | |
| 96 | static void parse_timeout(const char *p, struct timeout *t) |
| 97 | { |
| 98 | double x = 0; |
| 99 | char *q; |
| 100 | int oerr; |
| 101 | time_t t_max = timemax(); |
| 102 | struct timeval tv; |
| 103 | |
| 104 | if (strcmp(p, "forever") == 0) |
| 105 | t->wait = FOREVER; |
| 106 | else if (strcmp(p, "none") == 0 || strcmp(p, "never") == 0) |
| 107 | t->wait = NEVER; |
| 108 | else { |
| 109 | oerr = errno; errno = 0; |
| 110 | if (isspace((unsigned char)*p)) errno = EINVAL; |
| 111 | else x = strtod(p, &q); |
| 112 | if (x < 0) errno = ERANGE; |
| 113 | if (!errno) { |
| 114 | switch (tolower((unsigned char )*q)) { |
| 115 | case 'd': x *= 24; |
| 116 | case 'h': x *= 60; |
| 117 | case 'm': x *= 60; |
| 118 | case 's': q++; break; |
| 119 | } |
| 120 | if (*q) errno = EINVAL; |
| 121 | } |
| 122 | if (errno) die(253, "invalid timeout specification `%s'", p); |
| 123 | if (x >= t_max - now.tv_sec) t->wait = FOREVER; |
| 124 | else if (!x) t->wait = NEVER; |
| 125 | else { t->wait = UNTIL; f2tv(x, &tv); TV_ADD(&t->tv, &now, &tv); } |
| 126 | errno = oerr; |
| 127 | } |
| 128 | } |
| 129 | |
| 130 | /*----- Semaphore operations ----------------------------------------------*/ |
| 131 | |
| 132 | #define SEMA_PROJ 0xd1 /* fair die roll */ |
| 133 | |
| 134 | enum { NTY_PATH }; |
| 135 | struct nameinfo { |
| 136 | unsigned ty; |
| 137 | union { |
| 138 | const char *path; |
| 139 | } u; |
| 140 | }; |
| 141 | |
| 142 | static void parse_name(const char *name, struct nameinfo *ni) |
| 143 | { |
| 144 | size_t plen = strcspn(name, ":/"); |
| 145 | switch (name[plen]) { |
| 146 | case 0: case '/': ni->ty = NTY_PATH; ni->u.path = name; break; |
| 147 | case ':': |
| 148 | if (strncmp(name, "file:", 5) == 0) |
| 149 | { ni->ty = NTY_PATH; ni->u.path = name + plen + 1; } |
| 150 | else |
| 151 | die(253, "unknown name type `%.*s'", (int)plen, name); |
| 152 | break; |
| 153 | } |
| 154 | } |
| 155 | |
| 156 | static int sema_initialized_p(int semid) |
| 157 | { |
| 158 | union semun u; |
| 159 | struct semid_ds sem; |
| 160 | |
| 161 | u.buf = &sem; |
| 162 | if (semctl(semid, 0, IPC_STAT, u) < 0) { |
| 163 | die(254, "failed to check that semaphore set is initialized: %s", |
| 164 | strerror(errno)); |
| 165 | } |
| 166 | return (!!sem.sem_otime); |
| 167 | } |
| 168 | |
| 169 | static void make_sema_file(const char *name, int of, mode_t mode) |
| 170 | { |
| 171 | int fd; |
| 172 | struct nameinfo ni; |
| 173 | |
| 174 | parse_name(name, &ni); |
| 175 | if (ni.ty != NTY_PATH) |
| 176 | die(253, "semaphore name `%s' doesn't designate a path", name); |
| 177 | |
| 178 | if ((fd = open(ni.u.path, O_CREAT | of, mode)) < 0) { |
| 179 | die(254, "failed to create semaphore file `%s': %s", |
| 180 | ni.u.path, strerror(errno)); |
| 181 | } |
| 182 | close(fd); |
| 183 | } |
| 184 | |
| 185 | #define OF_PROBE 1u |
| 186 | #define OF_UNINIT 2u |
| 187 | |
| 188 | static int open_sema(const char *name, unsigned f, int of, |
| 189 | mode_t mode, int ival, |
| 190 | const struct timeout *t) |
| 191 | { |
| 192 | int ff = mode & 0777, rc, nrace = 5; |
| 193 | int semid; |
| 194 | union semun u; |
| 195 | struct sembuf buf[1]; |
| 196 | double w, ww; |
| 197 | struct nameinfo ni; |
| 198 | struct timeval tv, ttv; |
| 199 | key_t k; |
| 200 | |
| 201 | /* Turn the name into an IPC key. */ |
| 202 | parse_name(name, &ni); |
| 203 | assert(ni.ty == NTY_PATH); |
| 204 | if ((k = ftok(ni.u.path, SEMA_PROJ)) == (key_t)-1) { |
| 205 | die(254, "failed to get key from semaphore file `%s': %s", |
| 206 | ni.u.path, strerror(errno)); |
| 207 | } |
| 208 | |
| 209 | for (;;) { |
| 210 | /* Oh, horrors. A newly created semaphore set is uninitialized. But if |
| 211 | * we set IPC_CREAT without IPC_EXCL then we don't have any idea whether |
| 212 | * the semaphore set was created or not. So we have this little dance to |
| 213 | * do. |
| 214 | */ |
| 215 | if ((of & (O_CREAT | O_EXCL)) != (O_CREAT | O_EXCL)) { |
| 216 | semid = semget(k, 1, ff); |
| 217 | if (semid >= 0) goto await; |
| 218 | else if (errno != ENOENT) goto fail; |
| 219 | else if (ff & O_CREAT) /* try to create -- below */; |
| 220 | else if (f & OF_PROBE) return (-1); |
| 221 | else goto fail; |
| 222 | } |
| 223 | |
| 224 | /* So, here, we have O_CREAT set, and either the semaphore set doesn't |
| 225 | * seem to exist yet, or O_EXCL is set and we didn't bother checking yet. |
| 226 | * So now we try to create the set. If that fails with something other |
| 227 | * than EEXIST, or we were trying with O_EXCL, then we're done. |
| 228 | * Otherwise it's just appeared out of nowhere, so let's briefly try |
| 229 | * racing with whoever else it is, but give up if it doesn't look like |
| 230 | * we're likely to win. |
| 231 | */ |
| 232 | if ((semid = semget(k, 1, ff | IPC_CREAT | IPC_EXCL)) >= 0) break; |
| 233 | else if ((ff & O_EXCL) || errno != EEXIST || nrace--) goto fail; |
| 234 | } |
| 235 | |
| 236 | /* Right, we just created the semaphore set. Now we have to initialize it, |
| 237 | * because nobody did that for us. Set the initial value through semop to |
| 238 | * set the sem_otime stamp as an indicator that the set is properly |
| 239 | * initialized. |
| 240 | */ |
| 241 | u.val = ival ? 0 : 1; |
| 242 | buf[0].sem_num = 0; |
| 243 | buf[0].sem_op = ival ? ival : -1; |
| 244 | buf[0].sem_flg = IPC_NOWAIT; |
| 245 | if (semctl(semid, 0, SETVAL, u) < 0 || |
| 246 | semop(semid, buf, 1) < 0) |
| 247 | die(254, "failed to initialize semaphore set: %s", strerror(errno)); |
| 248 | |
| 249 | /* Whew. */ |
| 250 | return (semid); |
| 251 | |
| 252 | /* Make sure that the semaphore set is actually initialized before we |
| 253 | * continue. |
| 254 | */ |
| 255 | await: |
| 256 | if ((f & OF_UNINIT) || sema_initialized_p(semid)) return (semid); |
| 257 | if (t->wait == NEVER) goto notready; |
| 258 | w = 1e-4; |
| 259 | update_now(); |
| 260 | for (;;) { |
| 261 | ww = w/2 + w*rand()/RAND_MAX; f2tv(ww, &tv); TV_ADD(&tv, &tv, &now); |
| 262 | if (t->wait == UNTIL) { |
| 263 | if (TV_CMP(&now, >=, &t->tv)) goto notready; |
| 264 | if (TV_CMP(&tv, >, &t->tv)) tv = t->tv; |
| 265 | } |
| 266 | for (;;) { |
| 267 | TV_SUB(&ttv, &tv, &now); |
| 268 | rc = select(0, 0, 0, 0, &ttv); |
| 269 | update_now(); |
| 270 | if (!rc) break; |
| 271 | else if (errno != EINTR) |
| 272 | die(254, "unexpected error from select: %s", strerror(errno)); |
| 273 | } |
| 274 | if (sema_initialized_p(semid)) return (0); |
| 275 | w *= 2; |
| 276 | if (w >= 10) w = 10; |
| 277 | } |
| 278 | |
| 279 | /* Done. */ |
| 280 | return (semid); |
| 281 | |
| 282 | /* Report a get failure. */ |
| 283 | fail: |
| 284 | die(254, "failed to open semaphore set: %s", strerror(errno)); |
| 285 | |
| 286 | notready: |
| 287 | die(252, "semaphore set not ready"); |
| 288 | } |
| 289 | |
| 290 | static void rm_sema(int semid) |
| 291 | { |
| 292 | if (semctl(semid, 0, IPC_RMID)) |
| 293 | die(254, "failed to remove semaphore set: %s", strerror(errno)); |
| 294 | } |
| 295 | |
| 296 | static unsigned read_sema(int semid) |
| 297 | { |
| 298 | int val; |
| 299 | |
| 300 | if ((val = semctl(semid, 0, GETVAL)) < 0) |
| 301 | die(254, "failed to read semaphore value: %s", strerror(errno)); |
| 302 | return (val); |
| 303 | } |
| 304 | |
| 305 | static void set_sema(int semid, unsigned val) |
| 306 | { |
| 307 | union semun u; |
| 308 | |
| 309 | u.val = val; |
| 310 | if (semctl(semid, 0, SETVAL, u) < 0) |
| 311 | die(254, "failed to set semaphore value: %s", strerror(errno)); |
| 312 | } |
| 313 | |
| 314 | static void post_sema(int semid, int by) |
| 315 | { |
| 316 | struct sembuf buf[1]; |
| 317 | |
| 318 | buf[0].sem_num = 0; |
| 319 | buf[0].sem_op = by; |
| 320 | buf[0].sem_flg = 0; |
| 321 | if (semop(semid, buf, 1)) |
| 322 | die(254, "failed to post semaphore: %s", strerror(errno)); |
| 323 | } |
| 324 | |
| 325 | static struct sembuf *sigsembuf; |
| 326 | static int sigflag; |
| 327 | |
| 328 | static void wait_alarm(int hunoz) |
| 329 | { sigflag = 1; if (sigsembuf) sigsembuf->sem_flg |= IPC_NOWAIT; } |
| 330 | |
| 331 | static int wait_sema(int semid, int by, int flg, const struct timeout *t) |
| 332 | { |
| 333 | struct sembuf buf[1]; |
| 334 | struct sigaction sa, osa; |
| 335 | sigset_t ss, oss, ps; |
| 336 | struct timeval tv; |
| 337 | struct itimerval it, oit; |
| 338 | int rc, sig; |
| 339 | unsigned f = 0; |
| 340 | #define f_alarm 1u |
| 341 | |
| 342 | /* Set up the command buffer. */ |
| 343 | buf[0].sem_num = 0; |
| 344 | buf[0].sem_op = -by; |
| 345 | buf[0].sem_flg = flg; |
| 346 | |
| 347 | /* Modify it according to the timeout settings. */ |
| 348 | switch (t->wait) { |
| 349 | |
| 350 | case NEVER: |
| 351 | /* Don't wait. */ |
| 352 | buf[0].sem_flg |= IPC_NOWAIT; |
| 353 | break; |
| 354 | |
| 355 | case FOREVER: |
| 356 | /* Wait until it's ready. */ |
| 357 | break; |
| 358 | |
| 359 | case UNTIL: |
| 360 | /* Wait until the specified time. This is fiddly, and will likely |
| 361 | * require setting an alarm. |
| 362 | */ |
| 363 | |
| 364 | /* If the timeout is already in the past, then don't bother with the |
| 365 | * alarm, and simply don't wait. |
| 366 | */ |
| 367 | if (TV_CMP(&t->tv, <=, &now)) { |
| 368 | buf[0].sem_flg |= IPC_NOWAIT; |
| 369 | break; |
| 370 | } |
| 371 | |
| 372 | /* Find the current alarm setting. */ |
| 373 | if (getitimer(ITIMER_REAL, &oit)) { |
| 374 | die(254, "failed to read current alarm setting: %s", |
| 375 | strerror(errno)); |
| 376 | } |
| 377 | |
| 378 | /* If that's not set, or it's going to go off after our timeout, then |
| 379 | * we should override it temporarily. Otherwise, just let it do its |
| 380 | * (likely lethal) thing. |
| 381 | */ |
| 382 | if (!oit.it_value.tv_sec && !oit.it_value.tv_usec) |
| 383 | f |= f_alarm; |
| 384 | else { |
| 385 | TV_ADD(&oit.it_value, &oit.it_value, &now); |
| 386 | if (TV_CMP(&t->tv, <, &oit.it_value)) f |= f_alarm; |
| 387 | } |
| 388 | |
| 389 | /* If we are setting an alarm, then now is the time to mess about with |
| 390 | * signals and timers. |
| 391 | */ |
| 392 | if (f & f_alarm) { |
| 393 | |
| 394 | /* Mask out the signal while we fiddle with the settings. */ |
| 395 | sigemptyset(&ss); |
| 396 | sigaddset(&ss, SIGALRM); |
| 397 | if (sigprocmask(SIG_BLOCK, &ss, &oss)) |
| 398 | die(254, "failed to block alarm signal: %s", strerror(errno)); |
| 399 | |
| 400 | /* Establish our new signal handler. */ |
| 401 | sigsembuf = &buf[0]; |
| 402 | sigflag = 0; |
| 403 | sa.sa_handler = wait_alarm; |
| 404 | sa.sa_mask = ss; |
| 405 | sa.sa_flags = 0; |
| 406 | if (sigaction(SIGALRM, &sa, &osa)) |
| 407 | die(254, "failed to set alarm handler: %s", strerror(errno)); |
| 408 | |
| 409 | /* Set up the timer. */ |
| 410 | TV_SUB(&it.it_value, &t->tv, &now); |
| 411 | it.it_interval.tv_sec = 0; it.it_interval.tv_usec = 0; |
| 412 | if (setitimer(ITIMER_REAL, &it, 0)) |
| 413 | die(254, "failed to set alarm: %s", strerror(errno)); |
| 414 | |
| 415 | /* This bit's quite scummy. There isn't a POSIX-standard way to wait |
| 416 | * for a finite time before giving up, so we use alarms. But there |
| 417 | * also isn't a standard way to avoid a race between the alarm going |
| 418 | * off and us waiting for the semaphore, because semop doesn't have a |
| 419 | * signal set argument. So instead we have the signal handler frob |
| 420 | * the semop parameter block as well as setting a flag. Assuming |
| 421 | * that semop is actually a system call, then one of the following |
| 422 | * will happen: the signal will happen before the call, in which case |
| 423 | * it will set IPC_NOWAIT and semop will either succeed or fail |
| 424 | * immediately; the signal will happen during the call, while we're |
| 425 | * waiting for the semaphore, so semop will return with EINTR; or the |
| 426 | * signal will happen afterwards, by which point it's too late for us |
| 427 | * to care. |
| 428 | */ |
| 429 | compiler_fence(buf, &sigflag, FENCE_END); |
| 430 | if (sigprocmask(SIG_UNBLOCK, &ss, 0)) |
| 431 | die(254, "failed to unblock alarm signal: %s", strerror(errno)); |
| 432 | } |
| 433 | break; |
| 434 | } |
| 435 | |
| 436 | /* Wait for the semaphore. */ |
| 437 | if ((rc = semop(semid, buf, 1)) < 0 && |
| 438 | errno != EAGAIN && |
| 439 | !(errno == EINTR && sigflag)) |
| 440 | die(254, "failed to post semaphore: %s", strerror(errno)); |
| 441 | |
| 442 | /* Now we clean up again afterwards. */ |
| 443 | update_now(); |
| 444 | |
| 445 | /* If we set an alarm, we must dismantle it and restore the previous |
| 446 | * situation. |
| 447 | */ |
| 448 | if (f & f_alarm) { |
| 449 | |
| 450 | /* We're messing with the alarm again, so mask it out temporarily. */ |
| 451 | if (sigprocmask(SIG_BLOCK, &ss, &oss)) |
| 452 | die(254, "failed to block alarm signal: %s", strerror(errno)); |
| 453 | |
| 454 | /* Turn off the alarm timer. We don't need it any more. */ |
| 455 | it.it_value.tv_sec = 0; it.it_value.tv_usec = 0; |
| 456 | if (setitimer(ITIMER_REAL, &it, 0)) |
| 457 | die(254, "failed to disarm alarm timer: %s", strerror(errno)); |
| 458 | |
| 459 | /* At this point, if there's an alarm signal pending, it must be from the |
| 460 | * timer we set, and it's too late to do any good. So just clear it and |
| 461 | * move on. After this point, alarms will be from the previously |
| 462 | * established timer, and we should let them happen. |
| 463 | */ |
| 464 | if (sigpending(&ps)) |
| 465 | die(254, "failed to read pending signals: %s", strerror(errno)); |
| 466 | if (sigismember(&ps, SIGALRM) && sigwait(&ss, &sig)) |
| 467 | die(254, "failed to clear pending alarm: %s", strerror(errno)); |
| 468 | |
| 469 | /* Figure out how to restore the old timer. */ |
| 470 | if (oit.it_value.tv_sec || oit.it_value.tv_usec) { |
| 471 | if (TV_CMP(&oit.it_value, >, &now)) |
| 472 | TV_SUB(&oit.it_value, &oit.it_value, &now); |
| 473 | else { |
| 474 | /* We should have had an alarm by now. Schedule one for when we |
| 475 | * unblock the signal again. |
| 476 | */ |
| 477 | raise(SIGALRM); |
| 478 | |
| 479 | /* Sort out the timer again. */ |
| 480 | if (!oit.it_interval.tv_sec && !oit.it_interval.tv_usec) |
| 481 | oit.it_value.tv_sec = 0, oit.it_value.tv_usec = 0; |
| 482 | else { |
| 483 | TV_SUB(&tv, &now, &oit.it_value); |
| 484 | if (TV_CMP(&tv, <, &oit.it_interval)) |
| 485 | TV_SUB(&oit.it_value, &oit.it_interval, &tv); |
| 486 | else { |
| 487 | /* We've overshot the previous deadline, and missed at least one |
| 488 | * repetition. If this is bad, then we've already failed quite |
| 489 | * miserably. |
| 490 | */ |
| 491 | oit.it_value = oit.it_interval; |
| 492 | } |
| 493 | } |
| 494 | } |
| 495 | } |
| 496 | |
| 497 | /* We've now recovered the right settings, even if that's just to turn |
| 498 | * the alarm off, so go do that. |
| 499 | */ |
| 500 | if ((oit.it_value.tv_sec || oit.it_value.tv_usec) && |
| 501 | setitimer(ITIMER_REAL, &oit, 0)) |
| 502 | die(254, "failed to restore old alarm settings: %s", strerror(errno)); |
| 503 | |
| 504 | /* Restore the old signal handler. */ |
| 505 | if (sigaction(SIGALRM, &osa, 0)) |
| 506 | die(254, "failed to restore old alarm handler: %s", strerror(errno)); |
| 507 | |
| 508 | /* And finally we can restore the previous signal mask. */ |
| 509 | if (sigprocmask(SIG_SETMASK, &oss, 00)) |
| 510 | die(254, "failed to restore old signal mask: %s", strerror(errno)); |
| 511 | } |
| 512 | |
| 513 | return (rc ? -1 : 0); |
| 514 | } |
| 515 | |
| 516 | /*----- Main code ---------------------------------------------------------*/ |
| 517 | |
| 518 | static struct timeout timeout = { FOREVER }; |
| 519 | |
| 520 | static int cmd_mkfile(int argc, char *argv[]) |
| 521 | { |
| 522 | mode_t mode = 0666, mask = 0; |
| 523 | const char *name = 0; |
| 524 | int of = 0; |
| 525 | unsigned f = 0; |
| 526 | #define f_bogus 1u |
| 527 | #define f_mode 2u |
| 528 | |
| 529 | for (;;) { |
| 530 | static const struct option opts[] = { |
| 531 | { "mode", OPTF_ARGREQ, 0, 'm' }, |
| 532 | { "exclusive", 0, 0, 'x' }, |
| 533 | { 0, 0, 0, 0 } |
| 534 | }; |
| 535 | int o = mdwopt(argc, argv, "m:x", opts, 0, 0, OPTF_NOPROGNAME); |
| 536 | |
| 537 | if (o < 0) break; |
| 538 | switch (o) { |
| 539 | case 'm': |
| 540 | mode = parse_int("mode", optarg, 8, 0, 07777); |
| 541 | f |= f_mode; |
| 542 | break; |
| 543 | case 'x': of |= O_EXCL; break; |
| 544 | default: f |= f_bogus; break; |
| 545 | } |
| 546 | } |
| 547 | argc -= optind; argv += optind; |
| 548 | if (argc < 1) f |= f_bogus; |
| 549 | else { name = argv[0]; argc--; argv++; } |
| 550 | if (argc) f |= f_bogus; |
| 551 | if (f & f_bogus) return (-1); |
| 552 | |
| 553 | if (f & f_mode) mask = umask(0); |
| 554 | make_sema_file(name, of, mode); |
| 555 | if (f & f_mode) umask(mask); |
| 556 | return (0); |
| 557 | |
| 558 | #undef f_bogus |
| 559 | #undef f_mode |
| 560 | } |
| 561 | |
| 562 | static int cmd_new(int argc, char *argv[]) |
| 563 | { |
| 564 | mode_t mode = 0, mask; |
| 565 | const char *name = 0; |
| 566 | unsigned init = 0; |
| 567 | int of = O_CREAT; |
| 568 | unsigned f = 0; |
| 569 | #define f_bogus 1u |
| 570 | #define f_mode 2u |
| 571 | |
| 572 | for (;;) { |
| 573 | static const struct option opts[] = { |
| 574 | { "mode", OPTF_ARGREQ, 0, 'm' }, |
| 575 | { "exclusive", 0, 0, 'x' }, |
| 576 | { 0, 0, 0, 0 } |
| 577 | }; |
| 578 | int o = mdwopt(argc, argv, "m:x", opts, 0, 0, OPTF_NOPROGNAME); |
| 579 | |
| 580 | if (o < 0) break; |
| 581 | switch (o) { |
| 582 | case 'm': |
| 583 | mode = parse_int("mode", optarg, 8, 0, 0777); |
| 584 | f |= f_mode; |
| 585 | break; |
| 586 | case 'x': of |= O_EXCL; break; |
| 587 | default: f |= f_bogus; break; |
| 588 | } |
| 589 | } |
| 590 | argc -= optind; argv += optind; |
| 591 | if (argc < 2) f |= f_bogus; |
| 592 | else { |
| 593 | name = argv[0]; |
| 594 | init = parse_int("initial semaphore value", argv[1], |
| 595 | 0, 0, SEM_VALUE_MAX); |
| 596 | argc -= 2; argv += 2; |
| 597 | } |
| 598 | if (argc) f |= f_bogus; |
| 599 | if (f & f_bogus) return (-1); |
| 600 | |
| 601 | if (!(f & f_mode)) { |
| 602 | mask = umask(0); umask(mask); |
| 603 | mode = ~mask & 0777; |
| 604 | } |
| 605 | open_sema(name, 0, of, mode, init, &timeout); |
| 606 | return (0); |
| 607 | |
| 608 | #undef f_bogus |
| 609 | #undef f_mode |
| 610 | } |
| 611 | |
| 612 | static int cmd_rm(int argc, char *argv[]) |
| 613 | { |
| 614 | const char *name = 0; |
| 615 | unsigned f = 0, ff = 0; |
| 616 | int semid; |
| 617 | #define f_bogus 1u |
| 618 | |
| 619 | for (;;) { |
| 620 | static const struct option opts[] = { |
| 621 | { "force", 0, 0, 'f' }, |
| 622 | { 0, 0, 0, 0 } |
| 623 | }; |
| 624 | int o = mdwopt(argc, argv, "f", opts, 0, 0, OPTF_NOPROGNAME); |
| 625 | |
| 626 | if (o < 0) break; |
| 627 | switch (o) { |
| 628 | case 'f': ff |= OF_PROBE; break; |
| 629 | default: f |= f_bogus; break; |
| 630 | } |
| 631 | } |
| 632 | argc -= optind; argv += optind; |
| 633 | if (!argc) f |= f_bogus; |
| 634 | else { name = argv[0]; argc--; argv++; } |
| 635 | if (argc) f |= f_bogus; |
| 636 | if (f & f_bogus) return (-1); |
| 637 | |
| 638 | semid = open_sema(name, ff | OF_UNINIT, 0, 0, 0, &timeout); |
| 639 | if (semid >= 0) rm_sema(semid); |
| 640 | |
| 641 | return (0); |
| 642 | |
| 643 | #undef f_bogus |
| 644 | } |
| 645 | |
| 646 | static int cmd_set(int argc, char *argv[]) |
| 647 | { |
| 648 | const char *name = 0; |
| 649 | int semid; |
| 650 | unsigned n = 0; |
| 651 | unsigned f = 0; |
| 652 | #define f_bogus 1u |
| 653 | |
| 654 | for (;;) { |
| 655 | static const struct option opts[] = { |
| 656 | { 0, 0, 0, 0 } |
| 657 | }; |
| 658 | int o = mdwopt(argc, argv, "", opts, 0, 0, OPTF_NOPROGNAME); |
| 659 | |
| 660 | if (o < 0) break; |
| 661 | switch (o) { |
| 662 | default: f |= f_bogus; break; |
| 663 | } |
| 664 | } |
| 665 | argc -= optind; argv += optind; |
| 666 | if (argc < 2) f |= f_bogus; |
| 667 | else { |
| 668 | name = argv[0]; |
| 669 | n = parse_int("count", argv[1], 0, 0, SEM_VALUE_MAX); |
| 670 | argc -= 2; argv += 2; |
| 671 | } |
| 672 | if (argc) f |= f_bogus; |
| 673 | if (f & f_bogus) return (-1); |
| 674 | |
| 675 | semid = open_sema(name, 0, 0, 0, 0, &timeout); |
| 676 | set_sema(semid, n); |
| 677 | return (0); |
| 678 | |
| 679 | #undef f_bogus |
| 680 | } |
| 681 | |
| 682 | static int cmd_get(int argc, char *argv[]) |
| 683 | { |
| 684 | const char *name = 0; |
| 685 | int semid; |
| 686 | unsigned f = 0; |
| 687 | #define f_bogus 1u |
| 688 | |
| 689 | for (;;) { |
| 690 | static const struct option opts[] = { |
| 691 | { 0, 0, 0, 0 } |
| 692 | }; |
| 693 | int o = mdwopt(argc, argv, "", opts, 0, 0, OPTF_NOPROGNAME); |
| 694 | |
| 695 | if (o < 0) break; |
| 696 | switch (o) { |
| 697 | default: f |= f_bogus; break; |
| 698 | } |
| 699 | } |
| 700 | argc -= optind; argv += optind; |
| 701 | if (!argc) f |= f_bogus; |
| 702 | else { name = argv[0]; argc--; argv++; } |
| 703 | if (argc) f |= f_bogus; |
| 704 | if (f & f_bogus) return (-1); |
| 705 | |
| 706 | semid = open_sema(name, 0, 0, 0, 0, &timeout); |
| 707 | printf("%u\n", read_sema(semid)); |
| 708 | return (0); |
| 709 | |
| 710 | #undef f_bogus |
| 711 | } |
| 712 | |
| 713 | static int cmd_post(int argc, char *argv[]) |
| 714 | { |
| 715 | const char *name = 0; |
| 716 | int semid, n = 1; |
| 717 | unsigned f = 0; |
| 718 | #define f_bogus 1u |
| 719 | |
| 720 | for (;;) { |
| 721 | static const struct option opts[] = { |
| 722 | { "count", OPTF_ARGREQ, 0, 'n' }, |
| 723 | { 0, 0, 0, 0 } |
| 724 | }; |
| 725 | int o = mdwopt(argc, argv, "n:", opts, 0, 0, OPTF_NOPROGNAME); |
| 726 | |
| 727 | if (o < 0) break; |
| 728 | switch (o) { |
| 729 | case 'n': n = parse_int("count", optarg, 0, 1, SEM_VALUE_MAX); break; |
| 730 | default: f |= f_bogus; break; |
| 731 | } |
| 732 | } |
| 733 | argc -= optind; argv += optind; |
| 734 | if (!argc) f |= f_bogus; |
| 735 | else { name = argv[0]; argc--; argv++; } |
| 736 | if (argc) f |= f_bogus; |
| 737 | if (f & f_bogus) return (-1); |
| 738 | |
| 739 | semid = open_sema(name, 0, 0, 0, 0, &timeout); |
| 740 | post_sema(semid, n); |
| 741 | return (0); |
| 742 | |
| 743 | #undef f_bogus |
| 744 | } |
| 745 | |
| 746 | static int cmd_wait(int argc, char *argv[]) |
| 747 | { |
| 748 | const char *name = 0; |
| 749 | int semid, n = 1; |
| 750 | int flg = 0; |
| 751 | unsigned f = 0; |
| 752 | #define f_bogus 1u |
| 753 | |
| 754 | for (;;) { |
| 755 | static const struct option opts[] = { |
| 756 | { "count", OPTF_ARGREQ, 0, 'n' }, |
| 757 | { 0, 0, 0, 0 } |
| 758 | }; |
| 759 | int o = mdwopt(argc, argv, "-n:", opts, 0, 0, OPTF_NOPROGNAME); |
| 760 | |
| 761 | if (o < 0) break; |
| 762 | switch (o) { |
| 763 | case 'n': n = parse_int("count", optarg, 0, 1, SEM_VALUE_MAX); break; |
| 764 | case 0: |
| 765 | if (!name) name = optarg; |
| 766 | else { optind--; goto done_opts; } |
| 767 | break; |
| 768 | default: f |= f_bogus; break; |
| 769 | } |
| 770 | } |
| 771 | done_opts: |
| 772 | argc -= optind; argv += optind; |
| 773 | if (!name) { |
| 774 | if (!argc) f |= f_bogus; |
| 775 | else { name = argv[0]; argc--; argv++; } |
| 776 | } |
| 777 | if (argc) flg |= SEM_UNDO; |
| 778 | if (f & f_bogus) return (-1); |
| 779 | |
| 780 | semid = open_sema(name, 0, 0, 0, 0, &timeout); |
| 781 | if (wait_sema(semid, n, flg, &timeout)) |
| 782 | die(251, "semaphore busy"); |
| 783 | |
| 784 | if (argc) { |
| 785 | execvp(argv[0], argv); |
| 786 | die(254, "failed to exec `%s': %s", argv[0], strerror(errno)); |
| 787 | } |
| 788 | return (0); |
| 789 | |
| 790 | #undef f_bogus |
| 791 | } |
| 792 | |
| 793 | static const struct subcmd { |
| 794 | const char *name; |
| 795 | int (*func)(int, char *[]); |
| 796 | const char *usage; |
| 797 | } subcmds[] = { |
| 798 | { "mkfile", cmd_mkfile, "[-x] [-m MODE] NAME" }, |
| 799 | { "new", cmd_new, "[-x] [-m MODE] NAME VALUE" }, |
| 800 | { "rm", cmd_rm, "[-f] NAME" }, |
| 801 | { "get", cmd_get, "NAME" }, |
| 802 | { "set", cmd_set, "NAME VALUE" }, |
| 803 | { "post", cmd_post, "[-n COUNT] NAME" }, |
| 804 | { "wait", cmd_wait, "[-n COUNT] NAME [COMMAND ARGUMENTS ...]" }, |
| 805 | { 0, 0, 0 } |
| 806 | }; |
| 807 | |
| 808 | static void version(FILE *fp) |
| 809 | { pquis(fp, "$, version " VERSION "\n"); } |
| 810 | |
| 811 | static void usage(FILE *fp) |
| 812 | { |
| 813 | const struct subcmd *c; |
| 814 | |
| 815 | fprintf(fp, "usage:\n"); |
| 816 | for (c = subcmds; c->name; c++) |
| 817 | fprintf(fp, "\t%s [-OPTIONS] %s %s\n", QUIS, c->name, c->usage); |
| 818 | } |
| 819 | |
| 820 | static void help(FILE *fp) |
| 821 | { |
| 822 | version(fp); putc('\n', fp); |
| 823 | usage(fp); |
| 824 | fprintf(fp, "\n\ |
| 825 | Top-level options:\n\ |
| 826 | \n\ |
| 827 | -w, --wait=WHEN How long to wait (`forever', `never', or\n\ |
| 828 | nonnegative number followed by `s', `m',\n\ |
| 829 | `h', `d')\n"); |
| 830 | } |
| 831 | |
| 832 | int main(int argc, char *argv[]) |
| 833 | { |
| 834 | const struct subcmd *c; |
| 835 | int rc; |
| 836 | unsigned f = 0; |
| 837 | #define f_bogus 1u |
| 838 | |
| 839 | ego(argv[0]); |
| 840 | update_now(); |
| 841 | for (;;) { |
| 842 | static const struct option opts[] = { |
| 843 | { "help", 0, 0, 'h' }, |
| 844 | { "version", 0, 0, 'v' }, |
| 845 | { "wait", OPTF_ARGREQ, 0, 'w' }, |
| 846 | { 0, 0, 0, 0 } |
| 847 | }; |
| 848 | int o = mdwopt(argc, argv, "+hvw:", opts, 0, 0, 0); |
| 849 | |
| 850 | if (o < 0) break; |
| 851 | switch (o) { |
| 852 | case 'h': help(stdout); exit(0); break; |
| 853 | case 'v': version(stdout); exit(0); break; |
| 854 | case 'w': parse_timeout(optarg, &timeout); break; |
| 855 | default: f |= f_bogus; break; |
| 856 | } |
| 857 | } |
| 858 | argc -= optind; argv += optind; |
| 859 | if (!argc) f |= f_bogus; |
| 860 | if (f & f_bogus) { usage(stderr); exit(253); } |
| 861 | |
| 862 | optind = 0; |
| 863 | for (c = subcmds; c->name; c++) |
| 864 | if (strcmp(argv[0], c->name) == 0) goto found; |
| 865 | die(253, "unknown command `%s'", argv[0]); |
| 866 | found: |
| 867 | argc--; argv++; |
| 868 | rc = c->func(argc, argv); |
| 869 | if (rc < 0) { |
| 870 | fprintf(stderr, "usage: %s %s %s\n", QUIS, c->name, c->usage); |
| 871 | exit(253); |
| 872 | } |
| 873 | return (rc); |
| 874 | |
| 875 | #undef f_bogus |
| 876 | } |
| 877 | |
| 878 | /*----- That's all, folks -------------------------------------------------*/ |