sem.c revision 1.12
1 /* $NetBSD: sem.c,v 1.12 1998/07/28 02:23:39 mycroft Exp $ */ 2 3 /*- 4 * Copyright (c) 1980, 1991, 1993 5 * The Regents of the University of California. 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 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #include <sys/cdefs.h> 37 #ifndef lint 38 #if 0 39 static char sccsid[] = "@(#)sem.c 8.1 (Berkeley) 5/31/93"; 40 #else 41 __RCSID("$NetBSD: sem.c,v 1.12 1998/07/28 02:23:39 mycroft Exp $"); 42 #endif 43 #endif /* not lint */ 44 45 #include <sys/param.h> 46 #include <sys/ioctl.h> 47 #include <sys/stat.h> 48 #include <errno.h> 49 #include <fcntl.h> 50 #include <stdlib.h> 51 #include <string.h> 52 #include <unistd.h> 53 #if __STDC__ 54 # include <stdarg.h> 55 #else 56 # include <varargs.h> 57 #endif 58 59 #include "csh.h" 60 #include "proc.h" 61 #include "extern.h" 62 63 static void vffree __P((int)); 64 static Char *splicepipe __P((struct command *t, Char *)); 65 static void doio __P((struct command *t, int *, int *)); 66 static void chkclob __P((char *)); 67 68 void 69 execute(t, wanttty, pipein, pipeout) 70 struct command *t; 71 int wanttty, *pipein, *pipeout; 72 { 73 bool forked = 0; 74 struct biltins *bifunc; 75 int pid = 0; 76 int pv[2]; 77 sigset_t sigset; 78 79 static sigset_t csigset; 80 81 static sigset_t ocsigset; 82 static int onosigchld = 0; 83 static int nosigchld = 0; 84 85 UNREGISTER(forked); 86 UNREGISTER(bifunc); 87 UNREGISTER(wanttty); 88 89 if (t == 0) 90 return; 91 92 if (t->t_dflg & F_AMPERSAND) 93 wanttty = 0; 94 switch (t->t_dtyp) { 95 96 case NODE_COMMAND: 97 if ((t->t_dcom[0][0] & (QUOTE | TRIM)) == QUOTE) 98 (void) Strcpy(t->t_dcom[0], t->t_dcom[0] + 1); 99 if ((t->t_dflg & F_REPEAT) == 0) 100 Dfix(t); /* $ " ' \ */ 101 if (t->t_dcom[0] == 0) 102 return; 103 /* FALLTHROUGH */ 104 105 case NODE_PAREN: 106 if (t->t_dflg & F_PIPEOUT) 107 mypipe(pipeout); 108 /* 109 * Must do << early so parent will know where input pointer should be. 110 * If noexec then this is all we do. 111 */ 112 if (t->t_dflg & F_READ) { 113 (void) close(0); 114 heredoc(t->t_dlef); 115 if (noexec) 116 (void) close(0); 117 } 118 119 set(STRstatus, Strsave(STR0)); 120 121 /* 122 * This mess is the necessary kludge to handle the prefix builtins: 123 * nice, nohup, time. These commands can also be used by themselves, 124 * and this is not handled here. This will also work when loops are 125 * parsed. 126 */ 127 while (t->t_dtyp == NODE_COMMAND) 128 if (eq(t->t_dcom[0], STRnice)) 129 if (t->t_dcom[1]) 130 if (strchr("+-", t->t_dcom[1][0])) 131 if (t->t_dcom[2]) { 132 setname("nice"); 133 t->t_nice = 134 getn(t->t_dcom[1]); 135 lshift(t->t_dcom, 2); 136 t->t_dflg |= F_NICE; 137 } 138 else 139 break; 140 else { 141 t->t_nice = 4; 142 lshift(t->t_dcom, 1); 143 t->t_dflg |= F_NICE; 144 } 145 else 146 break; 147 else if (eq(t->t_dcom[0], STRnohup)) 148 if (t->t_dcom[1]) { 149 t->t_dflg |= F_NOHUP; 150 lshift(t->t_dcom, 1); 151 } 152 else 153 break; 154 else if (eq(t->t_dcom[0], STRtime)) 155 if (t->t_dcom[1]) { 156 t->t_dflg |= F_TIME; 157 lshift(t->t_dcom, 1); 158 } 159 else 160 break; 161 else 162 break; 163 164 /* is it a command */ 165 if (t->t_dtyp == NODE_COMMAND) { 166 /* 167 * Check if we have a builtin function and remember which one. 168 */ 169 bifunc = isbfunc(t); 170 if (noexec) { 171 /* 172 * Continue for builtins that are part of the scripting language 173 */ 174 if (bifunc->bfunct != dobreak && bifunc->bfunct != docontin && 175 bifunc->bfunct != doelse && bifunc->bfunct != doend && 176 bifunc->bfunct != doforeach && bifunc->bfunct != dogoto && 177 bifunc->bfunct != doif && bifunc->bfunct != dorepeat && 178 bifunc->bfunct != doswbrk && bifunc->bfunct != doswitch && 179 bifunc->bfunct != dowhile && bifunc->bfunct != dozip) 180 break; 181 } 182 } 183 else { /* not a command */ 184 bifunc = NULL; 185 if (noexec) 186 break; 187 } 188 189 /* 190 * We fork only if we are timed, or are not the end of a parenthesized 191 * list and not a simple builtin function. Simple meaning one that is 192 * not pipedout, niced, nohupped, or &'d. It would be nice(?) to not 193 * fork in some of these cases. 194 */ 195 /* 196 * Prevent forking cd, pushd, popd, chdir cause this will cause the 197 * shell not to change dir! 198 */ 199 if (bifunc && (bifunc->bfunct == dochngd || 200 bifunc->bfunct == dopushd || 201 bifunc->bfunct == dopopd)) 202 t->t_dflg &= ~(F_NICE); 203 if (((t->t_dflg & F_TIME) || ((t->t_dflg & F_NOFORK) == 0 && 204 (!bifunc || t->t_dflg & 205 (F_PIPEOUT | F_AMPERSAND | F_NICE | F_NOHUP)))) || 206 /* 207 * We have to fork for eval too. 208 */ 209 (bifunc && (t->t_dflg & (F_PIPEIN | F_PIPEOUT)) != 0 && 210 bifunc->bfunct == doeval)) 211 if (t->t_dtyp == NODE_PAREN || 212 t->t_dflg & (F_REPEAT | F_AMPERSAND) || bifunc) { 213 forked++; 214 /* 215 * We need to block SIGCHLD here, so that if the process does 216 * not die before we can set the process group 217 */ 218 if (wanttty >= 0 && !nosigchld) { 219 sigemptyset(&sigset); 220 sigaddset(&sigset, SIGCHLD); 221 sigprocmask(SIG_BLOCK, &sigset, &csigset); 222 nosigchld = 1; 223 } 224 225 pid = pfork(t, wanttty); 226 if (pid == 0 && nosigchld) { 227 sigprocmask(SIG_SETMASK, &csigset, NULL); 228 nosigchld = 0; 229 } 230 else if (pid != 0 && (t->t_dflg & F_AMPERSAND)) 231 backpid = pid; 232 233 } 234 else { 235 int ochild, osetintr, ohaderr, odidfds; 236 int oSHIN, oSHOUT, oSHERR, oOLDSTD, otpgrp; 237 sigset_t osigset; 238 239 /* 240 * Prepare for the vfork by saving everything that the child 241 * corrupts before it exec's. Note that in some signal 242 * implementations which keep the signal info in user space 243 * (e.g. Sun's) it will also be necessary to save and restore 244 * the current sigaction's for the signals the child touches 245 * before it exec's. 246 */ 247 if (wanttty >= 0 && !nosigchld && !noexec) { 248 sigemptyset(&sigset); 249 sigaddset(&sigset, SIGCHLD); 250 sigprocmask(SIG_BLOCK, &sigset, &csigset); 251 nosigchld = 1; 252 } 253 sigemptyset(&sigset); 254 sigaddset(&sigset, SIGCHLD); 255 sigaddset(&sigset, SIGINT); 256 sigprocmask(SIG_BLOCK, &sigset, &osigset); 257 ochild = child; 258 osetintr = setintr; 259 ohaderr = haderr; 260 odidfds = didfds; 261 oSHIN = SHIN; 262 oSHOUT = SHOUT; 263 oSHERR = SHERR; 264 oOLDSTD = OLDSTD; 265 otpgrp = tpgrp; 266 ocsigset = csigset; 267 onosigchld = nosigchld; 268 Vsav = Vdp = 0; 269 Vexpath = 0; 270 Vt = 0; 271 pid = vfork(); 272 273 if (pid < 0) { 274 sigprocmask(SIG_SETMASK, &osigset, NULL); 275 stderror(ERR_NOPROC); 276 /* NOTREACHED */ 277 } 278 forked++; 279 if (pid) { /* parent */ 280 child = ochild; 281 setintr = osetintr; 282 haderr = ohaderr; 283 didfds = odidfds; 284 SHIN = oSHIN; 285 SHOUT = oSHOUT; 286 SHERR = oSHERR; 287 OLDSTD = oOLDSTD; 288 tpgrp = otpgrp; 289 csigset = ocsigset; 290 nosigchld = onosigchld; 291 292 xfree((ptr_t) Vsav); 293 Vsav = 0; 294 xfree((ptr_t) Vdp); 295 Vdp = 0; 296 xfree((ptr_t) Vexpath); 297 Vexpath = 0; 298 blkfree((Char **) Vt); 299 Vt = 0; 300 /* this is from pfork() */ 301 palloc(pid, t); 302 sigprocmask(SIG_SETMASK, &osigset, NULL); 303 } 304 else { /* child */ 305 /* this is from pfork() */ 306 int pgrp; 307 bool ignint = 0; 308 309 if (nosigchld) { 310 sigprocmask(SIG_SETMASK, &csigset, NULL); 311 nosigchld = 0; 312 } 313 314 if (setintr) 315 ignint = 316 (tpgrp == -1 && 317 (t->t_dflg & F_NOINTERRUPT)) 318 || (gointr && eq(gointr, STRminus)); 319 pgrp = pcurrjob ? pcurrjob->p_jobid : getpid(); 320 child++; 321 if (setintr) { 322 setintr = 0; 323 if (ignint) { 324 (void) signal(SIGINT, SIG_IGN); 325 (void) signal(SIGQUIT, SIG_IGN); 326 } 327 else { 328 (void) signal(SIGINT, vffree); 329 (void) signal(SIGQUIT, SIG_DFL); 330 } 331 332 if (wanttty >= 0) { 333 (void) signal(SIGTSTP, SIG_DFL); 334 (void) signal(SIGTTIN, SIG_DFL); 335 (void) signal(SIGTTOU, SIG_DFL); 336 } 337 338 (void) signal(SIGTERM, parterm); 339 } 340 else if (tpgrp == -1 && 341 (t->t_dflg & F_NOINTERRUPT)) { 342 (void) signal(SIGINT, SIG_IGN); 343 (void) signal(SIGQUIT, SIG_IGN); 344 } 345 346 pgetty(wanttty, pgrp); 347 if (t->t_dflg & F_NOHUP) 348 (void) signal(SIGHUP, SIG_IGN); 349 if (t->t_dflg & F_NICE) 350 (void) setpriority(PRIO_PROCESS, 0, t->t_nice); 351 } 352 353 } 354 if (pid != 0) { 355 /* 356 * It would be better if we could wait for the whole job when we 357 * knew the last process had been started. Pwait, in fact, does 358 * wait for the whole job anyway, but this test doesn't really 359 * express our intentions. 360 */ 361 if (didfds == 0 && t->t_dflg & F_PIPEIN) { 362 (void) close(pipein[0]); 363 (void) close(pipein[1]); 364 } 365 if ((t->t_dflg & F_PIPEOUT) == 0) { 366 if (nosigchld) { 367 sigprocmask(SIG_SETMASK, &csigset, NULL); 368 nosigchld = 0; 369 } 370 if ((t->t_dflg & F_AMPERSAND) == 0) 371 pwait(); 372 } 373 break; 374 } 375 doio(t, pipein, pipeout); 376 if (t->t_dflg & F_PIPEOUT) { 377 (void) close(pipeout[0]); 378 (void) close(pipeout[1]); 379 } 380 /* 381 * Perform a builtin function. If we are not forked, arrange for 382 * possible stopping 383 */ 384 if (bifunc) { 385 func(t, bifunc); 386 if (forked) { 387 exitstat(); 388 /* NOTREACHED */ 389 } 390 break; 391 } 392 if (t->t_dtyp != NODE_PAREN) { 393 doexec(NULL, t); 394 /* NOTREACHED */ 395 } 396 /* 397 * For () commands must put new 0,1,2 in FSH* and recurse 398 */ 399 OLDSTD = dcopy(0, FOLDSTD); 400 SHOUT = dcopy(1, FSHOUT); 401 SHERR = dcopy(2, FSHERR); 402 (void) close(SHIN); 403 SHIN = -1; 404 didfds = 0; 405 wanttty = -1; 406 t->t_dspr->t_dflg |= t->t_dflg & F_NOINTERRUPT; 407 execute(t->t_dspr, wanttty, NULL, NULL); 408 exitstat(); 409 /* NOTREACHED */ 410 411 case NODE_PIPE: 412 t->t_dcar->t_dflg |= F_PIPEOUT | 413 (t->t_dflg & (F_PIPEIN | F_AMPERSAND | F_STDERR | F_NOINTERRUPT)); 414 execute(t->t_dcar, wanttty, pipein, pv); 415 t->t_dcdr->t_dflg |= F_PIPEIN | (t->t_dflg & 416 (F_PIPEOUT | F_AMPERSAND | F_NOFORK | F_NOINTERRUPT)); 417 if (wanttty > 0) 418 wanttty = 0; /* got tty already */ 419 execute(t->t_dcdr, wanttty, pv, pipeout); 420 break; 421 422 case NODE_LIST: 423 if (t->t_dcar) { 424 t->t_dcar->t_dflg |= t->t_dflg & F_NOINTERRUPT; 425 execute(t->t_dcar, wanttty, NULL, NULL); 426 /* 427 * In strange case of A&B make a new job after A 428 */ 429 if (t->t_dcar->t_dflg & F_AMPERSAND && t->t_dcdr && 430 (t->t_dcdr->t_dflg & F_AMPERSAND) == 0) 431 pendjob(); 432 } 433 if (t->t_dcdr) { 434 t->t_dcdr->t_dflg |= t->t_dflg & 435 (F_NOFORK | F_NOINTERRUPT); 436 execute(t->t_dcdr, wanttty, NULL, NULL); 437 } 438 break; 439 440 case NODE_OR: 441 case NODE_AND: 442 if (t->t_dcar) { 443 t->t_dcar->t_dflg |= t->t_dflg & F_NOINTERRUPT; 444 execute(t->t_dcar, wanttty, NULL, NULL); 445 if ((getn(value(STRstatus)) == 0) != 446 (t->t_dtyp == NODE_AND)) 447 return; 448 } 449 if (t->t_dcdr) { 450 t->t_dcdr->t_dflg |= t->t_dflg & 451 (F_NOFORK | F_NOINTERRUPT); 452 execute(t->t_dcdr, wanttty, NULL, NULL); 453 } 454 break; 455 } 456 /* 457 * Fall through for all breaks from switch 458 * 459 * If there will be no more executions of this command, flush all file 460 * descriptors. Places that turn on the F_REPEAT bit are responsible for 461 * doing donefds after the last re-execution 462 */ 463 if (didfds && !(t->t_dflg & F_REPEAT)) 464 donefds(); 465 } 466 467 static void 468 vffree(i) 469 int i; 470 { 471 Char **v; 472 473 if ((v = gargv) != NULL) { 474 gargv = 0; 475 xfree((ptr_t) v); 476 } 477 if ((v = pargv) != NULL) { 478 pargv = 0; 479 xfree((ptr_t) v); 480 } 481 _exit(i); 482 } 483 484 /* 485 * Expand and glob the words after an i/o redirection. 486 * If more than one word is generated, then update the command vector. 487 * 488 * This is done differently in all the shells: 489 * 1. in the bourne shell and ksh globbing is not performed 490 * 2. Bash/csh say ambiguous 491 * 3. zsh does i/o to/from all the files 492 * 4. itcsh concatenates the words. 493 * 494 * I don't know what is best to do. I think that Ambiguous is better 495 * than restructuring the command vector, because the user can get 496 * unexpected results. In any case, the command vector restructuring 497 * code is present and the user can choose it by setting noambiguous 498 */ 499 static Char * 500 splicepipe(t, cp) 501 struct command *t; 502 Char *cp; /* word after < or > */ 503 { 504 Char *blk[2]; 505 506 if (adrof(STRnoambiguous)) { 507 Char **pv; 508 509 blk[0] = Dfix1(cp); /* expand $ */ 510 blk[1] = NULL; 511 512 gflag = 0, tglob(blk); 513 if (gflag) { 514 pv = globall(blk); 515 if (pv == NULL) { 516 setname(vis_str(blk[0])); 517 xfree((ptr_t) blk[0]); 518 stderror(ERR_NAME | ERR_NOMATCH); 519 /* NOTREACHED */ 520 } 521 gargv = NULL; 522 if (pv[1] != NULL) { /* we need to fix the command vector */ 523 Char **av = blkspl(t->t_dcom, &pv[1]); 524 xfree((ptr_t) t->t_dcom); 525 t->t_dcom = av; 526 } 527 xfree((ptr_t) blk[0]); 528 blk[0] = pv[0]; 529 xfree((ptr_t) pv); 530 } 531 } 532 else { 533 blk[0] = globone(blk[1] = Dfix1(cp), G_ERROR); 534 xfree((ptr_t) blk[1]); 535 } 536 return(blk[0]); 537 } 538 539 /* 540 * Perform io redirection. 541 * We may or maynot be forked here. 542 */ 543 static void 544 doio(t, pipein, pipeout) 545 struct command *t; 546 int *pipein, *pipeout; 547 { 548 int fd; 549 Char *cp; 550 int flags = t->t_dflg; 551 552 if (didfds || (flags & F_REPEAT)) 553 return; 554 if ((flags & F_READ) == 0) {/* F_READ already done */ 555 if (t->t_dlef) { 556 char tmp[MAXPATHLEN+1]; 557 558 /* 559 * so < /dev/std{in,out,err} work 560 */ 561 (void) dcopy(SHIN, 0); 562 (void) dcopy(SHOUT, 1); 563 (void) dcopy(SHERR, 2); 564 cp = splicepipe(t, t->t_dlef); 565 (void) strncpy(tmp, short2str(cp), MAXPATHLEN); 566 tmp[MAXPATHLEN] = '\0'; 567 xfree((ptr_t) cp); 568 if ((fd = open(tmp, O_RDONLY)) < 0) { 569 stderror(ERR_SYSTEM, tmp, strerror(errno)); 570 /* NOTREACHED */ 571 } 572 (void) dmove(fd, 0); 573 } 574 else if (flags & F_PIPEIN) { 575 (void) close(0); 576 (void) dup(pipein[0]); 577 (void) close(pipein[0]); 578 (void) close(pipein[1]); 579 } 580 else if ((flags & F_NOINTERRUPT) && tpgrp == -1) { 581 (void) close(0); 582 (void) open(_PATH_DEVNULL, O_RDONLY); 583 } 584 else { 585 (void) close(0); 586 (void) dup(OLDSTD); 587 (void) ioctl(0, FIONCLEX, NULL); 588 } 589 } 590 if (t->t_drit) { 591 char tmp[MAXPATHLEN+1]; 592 593 cp = splicepipe(t, t->t_drit); 594 (void) strncpy(tmp, short2str(cp), MAXPATHLEN); 595 tmp[MAXPATHLEN] = '\0'; 596 xfree((ptr_t) cp); 597 /* 598 * so > /dev/std{out,err} work 599 */ 600 (void) dcopy(SHOUT, 1); 601 (void) dcopy(SHERR, 2); 602 if ((flags & F_APPEND) && 603 #ifdef O_APPEND 604 (fd = open(tmp, O_WRONLY | O_APPEND)) >= 0); 605 #else 606 (fd = open(tmp, O_WRONLY)) >= 0) 607 (void) lseek(1, (off_t) 0, SEEK_END); 608 #endif 609 else { 610 if (!(flags & F_OVERWRITE) && adrof(STRnoclobber)) { 611 if (flags & F_APPEND) { 612 stderror(ERR_SYSTEM, tmp, strerror(errno)); 613 /* NOTREACHED */ 614 } 615 chkclob(tmp); 616 } 617 if ((fd = open(tmp, O_WRONLY | O_CREAT | O_TRUNC, 0666)) < 0) { 618 stderror(ERR_SYSTEM, tmp, strerror(errno)); 619 /* NOTREACHED */ 620 } 621 } 622 (void) dmove(fd, 1); 623 } 624 else if (flags & F_PIPEOUT) { 625 (void) close(1); 626 (void) dup(pipeout[1]); 627 } 628 else { 629 (void) close(1); 630 (void) dup(SHOUT); 631 (void) ioctl(1, FIONCLEX, NULL); 632 } 633 634 (void) close(2); 635 if (flags & F_STDERR) { 636 (void) dup(1); 637 } 638 else { 639 (void) dup(SHERR); 640 (void) ioctl(2, FIONCLEX, NULL); 641 } 642 didfds = 1; 643 } 644 645 void 646 mypipe(pv) 647 int *pv; 648 { 649 650 if (pipe(pv) < 0) 651 goto oops; 652 pv[0] = dmove(pv[0], -1); 653 pv[1] = dmove(pv[1], -1); 654 if (pv[0] >= 0 && pv[1] >= 0) 655 return; 656 oops: 657 stderror(ERR_PIPE); 658 /* NOTREACHED */ 659 } 660 661 static void 662 chkclob(cp) 663 char *cp; 664 { 665 struct stat stb; 666 667 if (stat(cp, &stb) < 0) 668 return; 669 if (S_ISCHR(stb.st_mode)) 670 return; 671 stderror(ERR_EXISTS, cp); 672 /* NOTREACHED */ 673 } 674
Indexes created Mon Sep 22 13:09:51 GMT 2025