sem.c revision 1.7
1 /* $NetBSD: sem.c,v 1.7 1995/03/21 09:03:20 cgd 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 #ifndef lint 37 #if 0 38 static char sccsid[] = "@(#)sem.c 8.1 (Berkeley) 5/31/93"; 39 #else 40 static char rcsid[] = "$NetBSD: sem.c,v 1.7 1995/03/21 09:03:20 cgd Exp $"; 41 #endif 42 #endif /* not lint */ 43 44 #include <sys/param.h> 45 #include <sys/ioctl.h> 46 #include <sys/stat.h> 47 #include <errno.h> 48 #include <fcntl.h> 49 #include <stdlib.h> 50 #include <string.h> 51 #include <unistd.h> 52 #if __STDC__ 53 # include <stdarg.h> 54 #else 55 # include <varargs.h> 56 #endif 57 58 #include "csh.h" 59 #include "proc.h" 60 #include "extern.h" 61 62 static void vffree __P((int)); 63 static Char *splicepipe __P((struct command *t, Char *)); 64 static void doio __P((struct command *t, int *, int *)); 65 static void chkclob __P((char *)); 66 67 void 68 execute(t, wanttty, pipein, pipeout) 69 register struct command *t; 70 int wanttty, *pipein, *pipeout; 71 { 72 bool forked = 0; 73 struct biltins *bifunc; 74 int pid = 0; 75 int pv[2]; 76 77 static sigset_t csigmask; 78 79 static sigset_t ocsigmask; 80 static int onosigchld = 0; 81 static int nosigchld = 0; 82 83 UNREGISTER(forked); 84 UNREGISTER(bifunc); 85 UNREGISTER(wanttty); 86 87 if (t == 0) 88 return; 89 90 if (t->t_dflg & F_AMPERSAND) 91 wanttty = 0; 92 switch (t->t_dtyp) { 93 94 case NODE_COMMAND: 95 if ((t->t_dcom[0][0] & (QUOTE | TRIM)) == QUOTE) 96 (void) Strcpy(t->t_dcom[0], t->t_dcom[0] + 1); 97 if ((t->t_dflg & F_REPEAT) == 0) 98 Dfix(t); /* $ " ' \ */ 99 if (t->t_dcom[0] == 0) 100 return; 101 /* fall into... */ 102 103 case NODE_PAREN: 104 if (t->t_dflg & F_PIPEOUT) 105 mypipe(pipeout); 106 /* 107 * Must do << early so parent will know where input pointer should be. 108 * If noexec then this is all we do. 109 */ 110 if (t->t_dflg & F_READ) { 111 (void) close(0); 112 heredoc(t->t_dlef); 113 if (noexec) 114 (void) close(0); 115 } 116 117 set(STRstatus, Strsave(STR0)); 118 119 /* 120 * This mess is the necessary kludge to handle the prefix builtins: 121 * nice, nohup, time. These commands can also be used by themselves, 122 * and this is not handled here. This will also work when loops are 123 * parsed. 124 */ 125 while (t->t_dtyp == NODE_COMMAND) 126 if (eq(t->t_dcom[0], STRnice)) 127 if (t->t_dcom[1]) 128 if (strchr("+-", t->t_dcom[1][0])) 129 if (t->t_dcom[2]) { 130 setname("nice"); 131 t->t_nice = 132 getn(t->t_dcom[1]); 133 lshift(t->t_dcom, 2); 134 t->t_dflg |= F_NICE; 135 } 136 else 137 break; 138 else { 139 t->t_nice = 4; 140 lshift(t->t_dcom, 1); 141 t->t_dflg |= F_NICE; 142 } 143 else 144 break; 145 else if (eq(t->t_dcom[0], STRnohup)) 146 if (t->t_dcom[1]) { 147 t->t_dflg |= F_NOHUP; 148 lshift(t->t_dcom, 1); 149 } 150 else 151 break; 152 else if (eq(t->t_dcom[0], STRtime)) 153 if (t->t_dcom[1]) { 154 t->t_dflg |= F_TIME; 155 lshift(t->t_dcom, 1); 156 } 157 else 158 break; 159 else 160 break; 161 162 /* is it a command */ 163 if (t->t_dtyp == NODE_COMMAND) { 164 /* 165 * Check if we have a builtin function and remember which one. 166 */ 167 bifunc = isbfunc(t); 168 if (noexec) { 169 /* 170 * Continue for builtins that are part of the scripting language 171 */ 172 if (bifunc->bfunct != dobreak && bifunc->bfunct != docontin && 173 bifunc->bfunct != doelse && bifunc->bfunct != doend && 174 bifunc->bfunct != doforeach && bifunc->bfunct != dogoto && 175 bifunc->bfunct != doif && bifunc->bfunct != dorepeat && 176 bifunc->bfunct != doswbrk && bifunc->bfunct != doswitch && 177 bifunc->bfunct != dowhile && bifunc->bfunct != dozip) 178 break; 179 } 180 } 181 else { /* not a command */ 182 bifunc = NULL; 183 if (noexec) 184 break; 185 } 186 187 /* 188 * We fork only if we are timed, or are not the end of a parenthesized 189 * list and not a simple builtin function. Simple meaning one that is 190 * not pipedout, niced, nohupped, or &'d. It would be nice(?) to not 191 * fork in some of these cases. 192 */ 193 /* 194 * Prevent forking cd, pushd, popd, chdir cause this will cause the 195 * shell not to change dir! 196 */ 197 if (bifunc && (bifunc->bfunct == dochngd || 198 bifunc->bfunct == dopushd || 199 bifunc->bfunct == dopopd)) 200 t->t_dflg &= ~(F_NICE); 201 if (((t->t_dflg & F_TIME) || ((t->t_dflg & F_NOFORK) == 0 && 202 (!bifunc || t->t_dflg & 203 (F_PIPEOUT | F_AMPERSAND | F_NICE | F_NOHUP)))) || 204 /* 205 * We have to fork for eval too. 206 */ 207 (bifunc && (t->t_dflg & (F_PIPEIN | F_PIPEOUT)) != 0 && 208 bifunc->bfunct == doeval)) 209 if (t->t_dtyp == NODE_PAREN || 210 t->t_dflg & (F_REPEAT | F_AMPERSAND) || bifunc) { 211 forked++; 212 /* 213 * We need to block SIGCHLD here, so that if the process does 214 * not die before we can set the process group 215 */ 216 if (wanttty >= 0 && !nosigchld) { 217 csigmask = sigblock(sigmask(SIGCHLD)); 218 nosigchld = 1; 219 } 220 221 pid = pfork(t, wanttty); 222 if (pid == 0 && nosigchld) { 223 (void) sigsetmask(csigmask); 224 nosigchld = 0; 225 } 226 else if (pid != 0 && (t->t_dflg & F_AMPERSAND)) 227 backpid = pid; 228 229 } 230 else { 231 int ochild, osetintr, ohaderr, odidfds; 232 int oSHIN, oSHOUT, oSHERR, oOLDSTD, otpgrp; 233 sigset_t omask; 234 235 /* 236 * Prepare for the vfork by saving everything that the child 237 * corrupts before it exec's. Note that in some signal 238 * implementations which keep the signal info in user space 239 * (e.g. Sun's) it will also be necessary to save and restore 240 * the current sigvec's for the signals the child touches 241 * before it exec's. 242 */ 243 if (wanttty >= 0 && !nosigchld && !noexec) { 244 csigmask = sigblock(sigmask(SIGCHLD)); 245 nosigchld = 1; 246 } 247 omask = sigblock(sigmask(SIGCHLD) | sigmask(SIGINT)); 248 ochild = child; 249 osetintr = setintr; 250 ohaderr = haderr; 251 odidfds = didfds; 252 oSHIN = SHIN; 253 oSHOUT = SHOUT; 254 oSHERR = SHERR; 255 oOLDSTD = OLDSTD; 256 otpgrp = tpgrp; 257 ocsigmask = csigmask; 258 onosigchld = nosigchld; 259 Vsav = Vdp = 0; 260 Vexpath = 0; 261 Vt = 0; 262 pid = vfork(); 263 264 if (pid < 0) { 265 (void) sigsetmask(omask); 266 stderror(ERR_NOPROC); 267 } 268 forked++; 269 if (pid) { /* parent */ 270 child = ochild; 271 setintr = osetintr; 272 haderr = ohaderr; 273 didfds = odidfds; 274 SHIN = oSHIN; 275 SHOUT = oSHOUT; 276 SHERR = oSHERR; 277 OLDSTD = oOLDSTD; 278 tpgrp = otpgrp; 279 csigmask = ocsigmask; 280 nosigchld = onosigchld; 281 282 xfree((ptr_t) Vsav); 283 Vsav = 0; 284 xfree((ptr_t) Vdp); 285 Vdp = 0; 286 xfree((ptr_t) Vexpath); 287 Vexpath = 0; 288 blkfree((Char **) Vt); 289 Vt = 0; 290 /* this is from pfork() */ 291 palloc(pid, t); 292 (void) sigsetmask(omask); 293 } 294 else { /* child */ 295 /* this is from pfork() */ 296 int pgrp; 297 bool ignint = 0; 298 299 if (nosigchld) { 300 (void) sigsetmask(csigmask); 301 nosigchld = 0; 302 } 303 304 if (setintr) 305 ignint = 306 (tpgrp == -1 && 307 (t->t_dflg & F_NOINTERRUPT)) 308 || (gointr && eq(gointr, STRminus)); 309 pgrp = pcurrjob ? pcurrjob->p_jobid : getpid(); 310 child++; 311 if (setintr) { 312 setintr = 0; 313 if (ignint) { 314 (void) signal(SIGINT, SIG_IGN); 315 (void) signal(SIGQUIT, SIG_IGN); 316 } 317 else { 318 (void) signal(SIGINT, vffree); 319 (void) signal(SIGQUIT, SIG_DFL); 320 } 321 322 if (wanttty >= 0) { 323 (void) signal(SIGTSTP, SIG_DFL); 324 (void) signal(SIGTTIN, SIG_DFL); 325 (void) signal(SIGTTOU, SIG_DFL); 326 } 327 328 (void) signal(SIGTERM, parterm); 329 } 330 else if (tpgrp == -1 && 331 (t->t_dflg & F_NOINTERRUPT)) { 332 (void) signal(SIGINT, SIG_IGN); 333 (void) signal(SIGQUIT, SIG_IGN); 334 } 335 336 pgetty(wanttty, pgrp); 337 if (t->t_dflg & F_NOHUP) 338 (void) signal(SIGHUP, SIG_IGN); 339 if (t->t_dflg & F_NICE) 340 (void) setpriority(PRIO_PROCESS, 0, t->t_nice); 341 } 342 343 } 344 if (pid != 0) { 345 /* 346 * It would be better if we could wait for the whole job when we 347 * knew the last process had been started. Pwait, in fact, does 348 * wait for the whole job anyway, but this test doesn't really 349 * express our intentions. 350 */ 351 if (didfds == 0 && t->t_dflg & F_PIPEIN) { 352 (void) close(pipein[0]); 353 (void) close(pipein[1]); 354 } 355 if ((t->t_dflg & F_PIPEOUT) == 0) { 356 if (nosigchld) { 357 (void) sigsetmask(csigmask); 358 nosigchld = 0; 359 } 360 if ((t->t_dflg & F_AMPERSAND) == 0) 361 pwait(); 362 } 363 break; 364 } 365 doio(t, pipein, pipeout); 366 if (t->t_dflg & F_PIPEOUT) { 367 (void) close(pipeout[0]); 368 (void) close(pipeout[1]); 369 } 370 /* 371 * Perform a builtin function. If we are not forked, arrange for 372 * possible stopping 373 */ 374 if (bifunc) { 375 func(t, bifunc); 376 if (forked) 377 exitstat(); 378 break; 379 } 380 if (t->t_dtyp != NODE_PAREN) { 381 doexec(NULL, t); 382 /* NOTREACHED */ 383 } 384 /* 385 * For () commands must put new 0,1,2 in FSH* and recurse 386 */ 387 OLDSTD = dcopy(0, FOLDSTD); 388 SHOUT = dcopy(1, FSHOUT); 389 SHERR = dcopy(2, FSHERR); 390 (void) close(SHIN); 391 SHIN = -1; 392 didfds = 0; 393 wanttty = -1; 394 t->t_dspr->t_dflg |= t->t_dflg & F_NOINTERRUPT; 395 execute(t->t_dspr, wanttty, NULL, NULL); 396 exitstat(); 397 398 case NODE_PIPE: 399 t->t_dcar->t_dflg |= F_PIPEOUT | 400 (t->t_dflg & (F_PIPEIN | F_AMPERSAND | F_STDERR | F_NOINTERRUPT)); 401 execute(t->t_dcar, wanttty, pipein, pv); 402 t->t_dcdr->t_dflg |= F_PIPEIN | (t->t_dflg & 403 (F_PIPEOUT | F_AMPERSAND | F_NOFORK | F_NOINTERRUPT)); 404 if (wanttty > 0) 405 wanttty = 0; /* got tty already */ 406 execute(t->t_dcdr, wanttty, pv, pipeout); 407 break; 408 409 case NODE_LIST: 410 if (t->t_dcar) { 411 t->t_dcar->t_dflg |= t->t_dflg & F_NOINTERRUPT; 412 execute(t->t_dcar, wanttty, NULL, NULL); 413 /* 414 * In strange case of A&B make a new job after A 415 */ 416 if (t->t_dcar->t_dflg & F_AMPERSAND && t->t_dcdr && 417 (t->t_dcdr->t_dflg & F_AMPERSAND) == 0) 418 pendjob(); 419 } 420 if (t->t_dcdr) { 421 t->t_dcdr->t_dflg |= t->t_dflg & 422 (F_NOFORK | F_NOINTERRUPT); 423 execute(t->t_dcdr, wanttty, NULL, NULL); 424 } 425 break; 426 427 case NODE_OR: 428 case NODE_AND: 429 if (t->t_dcar) { 430 t->t_dcar->t_dflg |= t->t_dflg & F_NOINTERRUPT; 431 execute(t->t_dcar, wanttty, NULL, NULL); 432 if ((getn(value(STRstatus)) == 0) != 433 (t->t_dtyp == NODE_AND)) 434 return; 435 } 436 if (t->t_dcdr) { 437 t->t_dcdr->t_dflg |= t->t_dflg & 438 (F_NOFORK | F_NOINTERRUPT); 439 execute(t->t_dcdr, wanttty, NULL, NULL); 440 } 441 break; 442 } 443 /* 444 * Fall through for all breaks from switch 445 * 446 * If there will be no more executions of this command, flush all file 447 * descriptors. Places that turn on the F_REPEAT bit are responsible for 448 * doing donefds after the last re-execution 449 */ 450 if (didfds && !(t->t_dflg & F_REPEAT)) 451 donefds(); 452 } 453 454 static void 455 vffree(i) 456 int i; 457 { 458 register Char **v; 459 460 if ((v = gargv) != NULL) { 461 gargv = 0; 462 xfree((ptr_t) v); 463 } 464 if ((v = pargv) != NULL) { 465 pargv = 0; 466 xfree((ptr_t) v); 467 } 468 _exit(i); 469 } 470 471 /* 472 * Expand and glob the words after an i/o redirection. 473 * If more than one word is generated, then update the command vector. 474 * 475 * This is done differently in all the shells: 476 * 1. in the bourne shell and ksh globbing is not performed 477 * 2. Bash/csh say ambiguous 478 * 3. zsh does i/o to/from all the files 479 * 4. itcsh concatenates the words. 480 * 481 * I don't know what is best to do. I think that Ambiguous is better 482 * than restructuring the command vector, because the user can get 483 * unexpected results. In any case, the command vector restructuring 484 * code is present and the user can choose it by setting noambiguous 485 */ 486 static Char * 487 splicepipe(t, cp) 488 register struct command *t; 489 Char *cp; /* word after < or > */ 490 { 491 Char *blk[2]; 492 493 if (adrof(STRnoambiguous)) { 494 Char **pv; 495 496 blk[0] = Dfix1(cp); /* expand $ */ 497 blk[1] = NULL; 498 499 gflag = 0, tglob(blk); 500 if (gflag) { 501 pv = globall(blk); 502 if (pv == NULL) { 503 setname(vis_str(blk[0])); 504 xfree((ptr_t) blk[0]); 505 stderror(ERR_NAME | ERR_NOMATCH); 506 } 507 gargv = NULL; 508 if (pv[1] != NULL) { /* we need to fix the command vector */ 509 Char **av = blkspl(t->t_dcom, &pv[1]); 510 xfree((ptr_t) t->t_dcom); 511 t->t_dcom = av; 512 } 513 xfree((ptr_t) blk[0]); 514 blk[0] = pv[0]; 515 xfree((ptr_t) pv); 516 } 517 } 518 else { 519 blk[0] = globone(blk[1] = Dfix1(cp), G_ERROR); 520 xfree((ptr_t) blk[1]); 521 } 522 return(blk[0]); 523 } 524 525 /* 526 * Perform io redirection. 527 * We may or maynot be forked here. 528 */ 529 static void 530 doio(t, pipein, pipeout) 531 register struct command *t; 532 int *pipein, *pipeout; 533 { 534 register int fd; 535 register Char *cp; 536 register int flags = t->t_dflg; 537 538 if (didfds || (flags & F_REPEAT)) 539 return; 540 if ((flags & F_READ) == 0) {/* F_READ already done */ 541 if (t->t_dlef) { 542 char tmp[MAXPATHLEN+1]; 543 544 /* 545 * so < /dev/std{in,out,err} work 546 */ 547 (void) dcopy(SHIN, 0); 548 (void) dcopy(SHOUT, 1); 549 (void) dcopy(SHERR, 2); 550 cp = splicepipe(t, t->t_dlef); 551 (void) strncpy(tmp, short2str(cp), MAXPATHLEN); 552 tmp[MAXPATHLEN] = '\0'; 553 xfree((ptr_t) cp); 554 if ((fd = open(tmp, O_RDONLY)) < 0) 555 stderror(ERR_SYSTEM, tmp, strerror(errno)); 556 (void) dmove(fd, 0); 557 } 558 else if (flags & F_PIPEIN) { 559 (void) close(0); 560 (void) dup(pipein[0]); 561 (void) close(pipein[0]); 562 (void) close(pipein[1]); 563 } 564 else if ((flags & F_NOINTERRUPT) && tpgrp == -1) { 565 (void) close(0); 566 (void) open(_PATH_DEVNULL, O_RDONLY); 567 } 568 else { 569 (void) close(0); 570 (void) dup(OLDSTD); 571 (void) ioctl(0, FIONCLEX, NULL); 572 } 573 } 574 if (t->t_drit) { 575 char tmp[MAXPATHLEN+1]; 576 577 cp = splicepipe(t, t->t_drit); 578 (void) strncpy(tmp, short2str(cp), MAXPATHLEN); 579 tmp[MAXPATHLEN] = '\0'; 580 xfree((ptr_t) cp); 581 /* 582 * so > /dev/std{out,err} work 583 */ 584 (void) dcopy(SHOUT, 1); 585 (void) dcopy(SHERR, 2); 586 if ((flags & F_APPEND) && 587 #ifdef O_APPEND 588 (fd = open(tmp, O_WRONLY | O_APPEND)) >= 0); 589 #else 590 (fd = open(tmp, O_WRONLY)) >= 0) 591 (void) lseek(1, (off_t) 0, L_XTND); 592 #endif 593 else { 594 if (!(flags & F_OVERWRITE) && adrof(STRnoclobber)) { 595 if (flags & F_APPEND) 596 stderror(ERR_SYSTEM, tmp, strerror(errno)); 597 chkclob(tmp); 598 } 599 if ((fd = open(tmp, O_WRONLY | O_CREAT | O_TRUNC, 0666)) < 0) 600 stderror(ERR_SYSTEM, tmp, strerror(errno)); 601 } 602 (void) dmove(fd, 1); 603 } 604 else if (flags & F_PIPEOUT) { 605 (void) close(1); 606 (void) dup(pipeout[1]); 607 } 608 else { 609 (void) close(1); 610 (void) dup(SHOUT); 611 (void) ioctl(1, FIONCLEX, NULL); 612 } 613 614 (void) close(2); 615 if (flags & F_STDERR) { 616 (void) dup(1); 617 } 618 else { 619 (void) dup(SHERR); 620 (void) ioctl(2, FIONCLEX, NULL); 621 } 622 didfds = 1; 623 } 624 625 void 626 mypipe(pv) 627 register int *pv; 628 { 629 630 if (pipe(pv) < 0) 631 goto oops; 632 pv[0] = dmove(pv[0], -1); 633 pv[1] = dmove(pv[1], -1); 634 if (pv[0] >= 0 && pv[1] >= 0) 635 return; 636 oops: 637 stderror(ERR_PIPE); 638 } 639 640 static void 641 chkclob(cp) 642 register char *cp; 643 { 644 struct stat stb; 645 646 if (stat(cp, &stb) < 0) 647 return; 648 if (S_ISCHR(stb.st_mode)) 649 return; 650 stderror(ERR_EXISTS, cp); 651 } 652
Indexes created Wed Sep 24 05:09:52 GMT 2025