1 /* $OpenBSD: sem.c,v 1.8 2001/06/22 21:07:35 deraadt Exp $ */ 2 /* $NetBSD: sem.c,v 1.9 1995/09/27 00:38:50 jtc Exp $ */ 3 4 /*- 5 * Copyright (c) 1980, 1991, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #ifndef lint 38 #if 0 39 static char sccsid[] = "@(#)sem.c 8.1 (Berkeley) 5/31/93"; 40 #else 41 static char rcsid[] = "$OpenBSD: sem.c,v 1.8 2001/06/22 21:07:35 deraadt 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 #ifdef __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 register 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 /* fall into... */ 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 && 175 bifunc->bfunct != dobreak && bifunc->bfunct != docontin && 176 bifunc->bfunct != doelse && bifunc->bfunct != doend && 177 bifunc->bfunct != doforeach && bifunc->bfunct != dogoto && 178 bifunc->bfunct != doif && bifunc->bfunct != dorepeat && 179 bifunc->bfunct != doswbrk && bifunc->bfunct != doswitch && 180 bifunc->bfunct != dowhile && bifunc->bfunct != dozip) 181 break; 182 } 183 } 184 else { /* not a command */ 185 bifunc = NULL; 186 if (noexec) 187 break; 188 } 189 190 /* 191 * We fork only if we are timed, or are not the end of a parenthesized 192 * list and not a simple builtin function. Simple meaning one that is 193 * not pipedout, niced, nohupped, or &'d. It would be nice(?) to not 194 * fork in some of these cases. 195 */ 196 /* 197 * Prevent forking cd, pushd, popd, chdir cause this will cause the 198 * shell not to change dir! 199 */ 200 if (bifunc && (bifunc->bfunct == dochngd || 201 bifunc->bfunct == dopushd || 202 bifunc->bfunct == dopopd)) 203 t->t_dflg &= ~(F_NICE); 204 if (((t->t_dflg & F_TIME) || ((t->t_dflg & F_NOFORK) == 0 && 205 (!bifunc || t->t_dflg & 206 (F_PIPEOUT | F_AMPERSAND | F_NICE | F_NOHUP)))) || 207 /* 208 * We have to fork for eval too. 209 */ 210 (bifunc && (t->t_dflg & (F_PIPEIN | F_PIPEOUT)) != 0 && 211 bifunc->bfunct == doeval)) 212 if (t->t_dtyp == NODE_PAREN || 213 t->t_dflg & (F_REPEAT | F_AMPERSAND) || bifunc) { 214 forked++; 215 /* 216 * We need to block SIGCHLD here, so that if the process does 217 * not die before we can set the process group 218 */ 219 if (wanttty >= 0 && !nosigchld) { 220 sigemptyset(&sigset); 221 sigaddset(&sigset, SIGCHLD); 222 sigprocmask(SIG_BLOCK, &sigset, &csigset); 223 nosigchld = 1; 224 } 225 226 pid = pfork(t, wanttty); 227 if (pid == 0 && nosigchld) { 228 sigprocmask(SIG_SETMASK, &csigset, NULL); 229 nosigchld = 0; 230 } 231 else if (pid != 0 && (t->t_dflg & F_AMPERSAND)) 232 backpid = pid; 233 234 } 235 else { 236 int ochild, osetintr, ohaderr, odidfds; 237 int oSHIN, oSHOUT, oSHERR, oOLDSTD, otpgrp; 238 sigset_t osigset; 239 240 /* 241 * Prepare for the vfork by saving everything that the child 242 * corrupts before it exec's. Note that in some signal 243 * implementations which keep the signal info in user space 244 * (e.g. Sun's) it will also be necessary to save and restore 245 * the current sigaction's for the signals the child touches 246 * before it exec's. 247 */ 248 if (wanttty >= 0 && !nosigchld && !noexec) { 249 sigemptyset(&sigset); 250 sigaddset(&sigset, SIGCHLD); 251 sigprocmask(SIG_BLOCK, &sigset, &csigset); 252 nosigchld = 1; 253 } 254 sigemptyset(&sigset); 255 sigaddset(&sigset, SIGCHLD); 256 sigaddset(&sigset, SIGINT); 257 sigprocmask(SIG_BLOCK, &sigset, &osigset); 258 ochild = child; 259 osetintr = setintr; 260 ohaderr = haderr; 261 odidfds = didfds; 262 oSHIN = SHIN; 263 oSHOUT = SHOUT; 264 oSHERR = SHERR; 265 oOLDSTD = OLDSTD; 266 otpgrp = tpgrp; 267 ocsigset = csigset; 268 onosigchld = nosigchld; 269 Vsav = Vdp = 0; 270 Vexpath = 0; 271 Vt = 0; 272 pid = vfork(); 273 274 if (pid < 0) { 275 sigprocmask(SIG_SETMASK, &osigset, NULL); 276 stderror(ERR_NOPROC); 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 break; 389 } 390 if (t->t_dtyp != NODE_PAREN) { 391 doexec(NULL, t); 392 /* NOTREACHED */ 393 } 394 /* 395 * For () commands must put new 0,1,2 in FSH* and recurse 396 */ 397 OLDSTD = dcopy(0, FOLDSTD); 398 SHOUT = dcopy(1, FSHOUT); 399 SHERR = dcopy(2, FSHERR); 400 (void) close(SHIN); 401 SHIN = -1; 402 didfds = 0; 403 wanttty = -1; 404 t->t_dspr->t_dflg |= t->t_dflg & F_NOINTERRUPT; 405 execute(t->t_dspr, wanttty, NULL, NULL); 406 exitstat(); 407 408 case NODE_PIPE: 409 t->t_dcar->t_dflg |= F_PIPEOUT | 410 (t->t_dflg & (F_PIPEIN | F_AMPERSAND | F_STDERR | F_NOINTERRUPT)); 411 execute(t->t_dcar, wanttty, pipein, pv); 412 t->t_dcdr->t_dflg |= F_PIPEIN | (t->t_dflg & 413 (F_PIPEOUT | F_AMPERSAND | F_NOFORK | F_NOINTERRUPT)); 414 if (wanttty > 0) 415 wanttty = 0; /* got tty already */ 416 execute(t->t_dcdr, wanttty, pv, pipeout); 417 break; 418 419 case NODE_LIST: 420 if (t->t_dcar) { 421 t->t_dcar->t_dflg |= t->t_dflg & F_NOINTERRUPT; 422 execute(t->t_dcar, wanttty, NULL, NULL); 423 /* 424 * In strange case of A&B make a new job after A 425 */ 426 if (t->t_dcar->t_dflg & F_AMPERSAND && t->t_dcdr && 427 (t->t_dcdr->t_dflg & F_AMPERSAND) == 0) 428 pendjob(); 429 } 430 if (t->t_dcdr) { 431 t->t_dcdr->t_dflg |= t->t_dflg & 432 (F_NOFORK | F_NOINTERRUPT); 433 execute(t->t_dcdr, wanttty, NULL, NULL); 434 } 435 break; 436 437 case NODE_OR: 438 case NODE_AND: 439 if (t->t_dcar) { 440 t->t_dcar->t_dflg |= t->t_dflg & F_NOINTERRUPT; 441 execute(t->t_dcar, wanttty, NULL, NULL); 442 if ((getn(value(STRstatus)) == 0) != 443 (t->t_dtyp == NODE_AND)) 444 return; 445 } 446 if (t->t_dcdr) { 447 t->t_dcdr->t_dflg |= t->t_dflg & 448 (F_NOFORK | F_NOINTERRUPT); 449 execute(t->t_dcdr, wanttty, NULL, NULL); 450 } 451 break; 452 } 453 /* 454 * Fall through for all breaks from switch 455 * 456 * If there will be no more executions of this command, flush all file 457 * descriptors. Places that turn on the F_REPEAT bit are responsible for 458 * doing donefds after the last re-execution 459 */ 460 if (didfds && !(t->t_dflg & F_REPEAT)) 461 donefds(); 462 } 463 464 static void 465 vffree(i) 466 int i; 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]; 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 strlcpy(tmp, short2str(cp), sizeof tmp); 552 xfree((ptr_t) cp); 553 if ((fd = open(tmp, O_RDONLY)) < 0) 554 stderror(ERR_SYSTEM, tmp, strerror(errno)); 555 (void) dmove(fd, 0); 556 } 557 else if (flags & F_PIPEIN) { 558 (void) close(0); 559 (void) dup(pipein[0]); 560 (void) close(pipein[0]); 561 (void) close(pipein[1]); 562 } 563 else if ((flags & F_NOINTERRUPT) && tpgrp == -1) { 564 (void) close(0); 565 (void) open(_PATH_DEVNULL, O_RDONLY); 566 } 567 else { 568 (void) close(0); 569 (void) dup(OLDSTD); 570 (void) ioctl(0, FIONCLEX, NULL); 571 } 572 } 573 if (t->t_drit) { 574 char tmp[MAXPATHLEN]; 575 576 cp = splicepipe(t, t->t_drit); 577 strlcpy(tmp, short2str(cp), sizeof tmp); 578 xfree((ptr_t) cp); 579 /* 580 * so > /dev/std{out,err} work 581 */ 582 (void) dcopy(SHOUT, 1); 583 (void) dcopy(SHERR, 2); 584 if ((flags & F_APPEND) && 585 #ifdef O_APPEND 586 (fd = open(tmp, O_WRONLY | O_APPEND)) >= 0); 587 #else 588 (fd = open(tmp, O_WRONLY)) >= 0) 589 (void) lseek(1, (off_t) 0, SEEK_END); 590 #endif 591 else { 592 if (!(flags & F_OVERWRITE) && adrof(STRnoclobber)) { 593 if (flags & F_APPEND) 594 stderror(ERR_SYSTEM, tmp, strerror(errno)); 595 chkclob(tmp); 596 } 597 if ((fd = open(tmp, O_WRONLY | O_CREAT | O_TRUNC, 0666)) < 0) 598 stderror(ERR_SYSTEM, tmp, strerror(errno)); 599 } 600 (void) dmove(fd, 1); 601 } 602 else if (flags & F_PIPEOUT) { 603 (void) close(1); 604 (void) dup(pipeout[1]); 605 } 606 else { 607 (void) close(1); 608 (void) dup(SHOUT); 609 (void) ioctl(1, FIONCLEX, NULL); 610 } 611 612 (void) close(2); 613 if (flags & F_STDERR) { 614 (void) dup(1); 615 } 616 else { 617 (void) dup(SHERR); 618 (void) ioctl(2, FIONCLEX, NULL); 619 } 620 didfds = 1; 621 } 622 623 void 624 mypipe(pv) 625 register int *pv; 626 { 627 628 if (pipe(pv) < 0) 629 goto oops; 630 pv[0] = dmove(pv[0], -1); 631 pv[1] = dmove(pv[1], -1); 632 if (pv[0] >= 0 && pv[1] >= 0) 633 return; 634 oops: 635 stderror(ERR_PIPE); 636 } 637 638 static void 639 chkclob(cp) 640 register char *cp; 641 { 642 struct stat stb; 643 644 if (stat(cp, &stb) < 0) 645 return; 646 if (S_ISCHR(stb.st_mode)) 647 return; 648 stderror(ERR_EXISTS, cp); 649 } 650