1 /* $OpenBSD: sem.c,v 1.25 2024/08/20 23:40:39 guenther 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. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #include <sys/types.h> 34 #include <sys/stat.h> 35 #include <errno.h> 36 #include <fcntl.h> 37 #include <stdlib.h> 38 #include <string.h> 39 #include <unistd.h> 40 #include <limits.h> 41 #include <stdarg.h> 42 43 #include "csh.h" 44 #include "proc.h" 45 #include "extern.h" 46 47 static void vffree(int); 48 static Char *splicepipe(struct command *t, Char *); 49 static void doio(struct command *t, int *, int *); 50 static void chkclob(char *); 51 52 void 53 execute(struct command *t, int wanttty, int *pipein, int *pipeout) 54 { 55 bool forked = 0; 56 struct biltins *bifunc; 57 int pid = 0; 58 int pv[2]; 59 sigset_t sigset; 60 61 static sigset_t csigset; 62 63 static sigset_t ocsigset; 64 static int onosigchld = 0; 65 static int nosigchld = 0; 66 67 UNREGISTER(forked); 68 UNREGISTER(bifunc); 69 UNREGISTER(wanttty); 70 71 if (t == 0) 72 return; 73 74 if (t->t_dflg & F_AMPERSAND) 75 wanttty = 0; 76 switch (t->t_dtyp) { 77 78 case NODE_COMMAND: 79 if ((t->t_dcom[0][0] & (QUOTE | TRIM)) == QUOTE) 80 (void) memmove(t->t_dcom[0], t->t_dcom[0] + 1, 81 (Strlen(t->t_dcom[0] + 1) + 1) * sizeof(Char)); 82 if ((t->t_dflg & F_REPEAT) == 0) 83 Dfix(t); /* $ " ' \ */ 84 if (t->t_dcom[0] == 0) 85 return; 86 /* fall into... */ 87 88 case NODE_PAREN: 89 if (t->t_dflg & F_PIPEOUT) 90 mypipe(pipeout); 91 /* 92 * Must do << early so parent will know where input pointer should be. 93 * If noexec then this is all we do. 94 */ 95 if (t->t_dflg & F_READ) { 96 (void) close(0); 97 heredoc(t->t_dlef); 98 if (noexec) 99 (void) close(0); 100 } 101 102 set(STRstatus, Strsave(STR0)); 103 104 /* 105 * This mess is the necessary kludge to handle the prefix builtins: 106 * nice, nohup, time. These commands can also be used by themselves, 107 * and this is not handled here. This will also work when loops are 108 * parsed. 109 */ 110 while (t->t_dtyp == NODE_COMMAND) 111 if (eq(t->t_dcom[0], STRnice)) 112 if (t->t_dcom[1]) 113 if (strchr("+-", t->t_dcom[1][0])) 114 if (t->t_dcom[2]) { 115 setname("nice"); 116 t->t_nice = 117 getn(t->t_dcom[1]); 118 lshift(t->t_dcom, 2); 119 t->t_dflg |= F_NICE; 120 } 121 else 122 break; 123 else { 124 t->t_nice = 4; 125 lshift(t->t_dcom, 1); 126 t->t_dflg |= F_NICE; 127 } 128 else 129 break; 130 else if (eq(t->t_dcom[0], STRnohup)) 131 if (t->t_dcom[1]) { 132 t->t_dflg |= F_NOHUP; 133 lshift(t->t_dcom, 1); 134 } 135 else 136 break; 137 else if (eq(t->t_dcom[0], STRtime)) 138 if (t->t_dcom[1]) { 139 t->t_dflg |= F_TIME; 140 lshift(t->t_dcom, 1); 141 } 142 else 143 break; 144 else 145 break; 146 147 /* is it a command */ 148 if (t->t_dtyp == NODE_COMMAND) { 149 /* 150 * Check if we have a builtin function and remember which one. 151 */ 152 bifunc = isbfunc(t); 153 if (noexec) { 154 /* 155 * Continue for builtins that are part of the scripting language 156 */ 157 if (bifunc && 158 bifunc->bfunct != dobreak && bifunc->bfunct != docontin && 159 bifunc->bfunct != doelse && bifunc->bfunct != doend && 160 bifunc->bfunct != doforeach && bifunc->bfunct != dogoto && 161 bifunc->bfunct != doif && bifunc->bfunct != dorepeat && 162 bifunc->bfunct != doswbrk && bifunc->bfunct != doswitch && 163 bifunc->bfunct != dowhile && bifunc->bfunct != dozip) 164 break; 165 } 166 } 167 else { /* not a command */ 168 bifunc = NULL; 169 if (noexec) 170 break; 171 } 172 173 /* 174 * We fork only if we are timed, or are not the end of a parenthesized 175 * list and not a simple builtin function. Simple meaning one that is 176 * not pipedout, niced, nohupped, or &'d. It would be nice(?) to not 177 * fork in some of these cases. 178 */ 179 /* 180 * Prevent forking cd, pushd, popd, chdir cause this will cause the 181 * shell not to change dir! 182 */ 183 if (bifunc && (bifunc->bfunct == dochngd || 184 bifunc->bfunct == dopushd || 185 bifunc->bfunct == dopopd)) 186 t->t_dflg &= ~(F_NICE); 187 if (((t->t_dflg & F_TIME) || ((t->t_dflg & F_NOFORK) == 0 && 188 (!bifunc || t->t_dflg & 189 (F_PIPEOUT | F_AMPERSAND | F_NICE | F_NOHUP)))) || 190 /* 191 * We have to fork for eval too. 192 */ 193 (bifunc && (t->t_dflg & (F_PIPEIN | F_PIPEOUT)) != 0 && 194 bifunc->bfunct == doeval)) { 195 if (t->t_dtyp == NODE_PAREN || 196 t->t_dflg & (F_REPEAT | F_AMPERSAND) || bifunc) { 197 forked++; 198 /* 199 * We need to block SIGCHLD/SIGHUP here, so that if the process does 200 * not die before we can set the process group 201 */ 202 if (wanttty >= 0 && !nosigchld) { 203 sigemptyset(&sigset); 204 sigaddset(&sigset, SIGCHLD); 205 sigaddset(&sigset, SIGHUP); 206 sigprocmask(SIG_BLOCK, &sigset, &csigset); 207 nosigchld = 1; 208 } 209 210 pid = pfork(t, wanttty); 211 if (pid == 0 && nosigchld) { 212 sigprocmask(SIG_SETMASK, &csigset, NULL); 213 nosigchld = 0; 214 } 215 else if (pid != 0 && (t->t_dflg & F_AMPERSAND)) 216 backpid = pid; 217 218 } 219 else { 220 int ochild, osetintr, ohaderr, odidfds; 221 int oSHIN, oSHOUT, oSHERR, oOLDSTD, otpgrp; 222 sigset_t osigset; 223 224 /* 225 * Prepare for the vfork by saving everything that the child 226 * corrupts before it exec's. Note that in some signal 227 * implementations which keep the signal info in user space 228 * (e.g. Sun's) it will also be necessary to save and restore 229 * the current sigaction's for the signals the child touches 230 * before it exec's. 231 */ 232 if (wanttty >= 0 && !nosigchld && !noexec) { 233 sigemptyset(&sigset); 234 sigaddset(&sigset, SIGCHLD); 235 sigaddset(&sigset, SIGHUP); 236 sigprocmask(SIG_BLOCK, &sigset, &csigset); 237 nosigchld = 1; 238 } 239 sigemptyset(&sigset); 240 sigaddset(&sigset, SIGCHLD); 241 sigaddset(&sigset, SIGHUP); 242 sigaddset(&sigset, SIGINT); 243 sigprocmask(SIG_BLOCK, &sigset, &osigset); 244 ochild = child; 245 osetintr = setintr; 246 ohaderr = haderr; 247 odidfds = didfds; 248 oSHIN = SHIN; 249 oSHOUT = SHOUT; 250 oSHERR = SHERR; 251 oOLDSTD = OLDSTD; 252 otpgrp = tpgrp; 253 ocsigset = csigset; 254 onosigchld = nosigchld; 255 Vsav = Vdp = NULL; 256 Vexpath = 0; 257 Vt = 0; 258 pid = vfork(); 259 260 if (pid == -1) { 261 sigprocmask(SIG_SETMASK, &osigset, NULL); 262 stderror(ERR_NOPROC); 263 } 264 forked++; 265 if (pid) { /* parent */ 266 child = ochild; 267 setintr = osetintr; 268 haderr = ohaderr; 269 didfds = odidfds; 270 SHIN = oSHIN; 271 SHOUT = oSHOUT; 272 SHERR = oSHERR; 273 OLDSTD = oOLDSTD; 274 tpgrp = otpgrp; 275 csigset = ocsigset; 276 nosigchld = onosigchld; 277 278 free(Vsav); 279 Vsav = NULL; 280 free(Vdp); 281 Vdp = NULL; 282 free(Vexpath); 283 Vexpath = NULL; 284 blkfree((Char **) Vt); 285 Vt = NULL; 286 /* this is from pfork() */ 287 palloc(pid, t); 288 sigprocmask(SIG_SETMASK, &osigset, NULL); 289 } 290 else { /* child */ 291 /* this is from pfork() */ 292 int pgrp; 293 bool ignint = 0; 294 295 if (nosigchld) { 296 sigprocmask(SIG_SETMASK, &csigset, NULL); 297 nosigchld = 0; 298 } 299 300 if (setintr) 301 ignint = 302 (tpgrp == -1 && 303 (t->t_dflg & F_NOINTERRUPT)) 304 || (gointr && eq(gointr, STRminus)); 305 pgrp = pcurrjob ? pcurrjob->p_jobid : getpid(); 306 child++; 307 if (setintr) { 308 setintr = 0; 309 if (ignint) { 310 (void) signal(SIGINT, SIG_IGN); 311 (void) signal(SIGQUIT, SIG_IGN); 312 } 313 else { 314 (void) signal(SIGINT, vffree); 315 (void) signal(SIGQUIT, SIG_DFL); 316 } 317 318 if (wanttty >= 0) { 319 (void) signal(SIGTSTP, SIG_DFL); 320 (void) signal(SIGTTIN, SIG_DFL); 321 (void) signal(SIGTTOU, SIG_DFL); 322 } 323 324 (void) signal(SIGTERM, parterm); 325 } 326 else if (tpgrp == -1 && 327 (t->t_dflg & F_NOINTERRUPT)) { 328 (void) signal(SIGINT, SIG_IGN); 329 (void) signal(SIGQUIT, SIG_IGN); 330 } 331 332 pgetty(wanttty, pgrp); 333 if (t->t_dflg & F_NOHUP) 334 (void) signal(SIGHUP, SIG_IGN); 335 if (t->t_dflg & F_NICE) 336 (void) setpriority(PRIO_PROCESS, 0, t->t_nice); 337 } 338 339 } 340 } 341 if (pid != 0) { 342 /* 343 * It would be better if we could wait for the whole job when we 344 * knew the last process had been started. Pwait, in fact, does 345 * wait for the whole job anyway, but this test doesn't really 346 * express our intentions. 347 */ 348 if (didfds == 0 && t->t_dflg & F_PIPEIN) { 349 (void) close(pipein[0]); 350 (void) close(pipein[1]); 351 } 352 if ((t->t_dflg & F_PIPEOUT) == 0) { 353 if (nosigchld) { 354 sigprocmask(SIG_SETMASK, &csigset, NULL); 355 nosigchld = 0; 356 } 357 if ((t->t_dflg & F_AMPERSAND) == 0) 358 pwait(); 359 } 360 break; 361 } 362 doio(t, pipein, pipeout); 363 if (t->t_dflg & F_PIPEOUT) { 364 (void) close(pipeout[0]); 365 (void) close(pipeout[1]); 366 } 367 /* 368 * Perform a builtin function. If we are not forked, arrange for 369 * possible stopping 370 */ 371 if (bifunc) { 372 func(t, bifunc); 373 if (forked) 374 exitstat(); 375 break; 376 } 377 if (t->t_dtyp != NODE_PAREN) { 378 doexec(NULL, t); 379 /* NOTREACHED */ 380 } 381 /* 382 * For () commands must put new 0,1,2 in FSH* and recurse 383 */ 384 OLDSTD = dcopy(0, FOLDSTD); 385 SHOUT = dcopy(1, FSHOUT); 386 SHERR = dcopy(2, FSHERR); 387 (void) close(SHIN); 388 SHIN = -1; 389 didfds = 0; 390 wanttty = -1; 391 t->t_dspr->t_dflg |= t->t_dflg & F_NOINTERRUPT; 392 execute(t->t_dspr, wanttty, NULL, NULL); 393 exitstat(); 394 395 case NODE_PIPE: 396 t->t_dcar->t_dflg |= F_PIPEOUT | 397 (t->t_dflg & (F_PIPEIN | F_AMPERSAND | F_STDERR | F_NOINTERRUPT)); 398 execute(t->t_dcar, wanttty, pipein, pv); 399 t->t_dcdr->t_dflg |= F_PIPEIN | (t->t_dflg & 400 (F_PIPEOUT | F_AMPERSAND | F_NOFORK | F_NOINTERRUPT)); 401 if (wanttty > 0) 402 wanttty = 0; /* got tty already */ 403 execute(t->t_dcdr, wanttty, pv, pipeout); 404 break; 405 406 case NODE_LIST: 407 if (t->t_dcar) { 408 t->t_dcar->t_dflg |= t->t_dflg & F_NOINTERRUPT; 409 execute(t->t_dcar, wanttty, NULL, NULL); 410 /* 411 * In strange case of A&B make a new job after A 412 */ 413 if (t->t_dcar->t_dflg & F_AMPERSAND && t->t_dcdr && 414 (t->t_dcdr->t_dflg & F_AMPERSAND) == 0) 415 pendjob(); 416 } 417 if (t->t_dcdr) { 418 t->t_dcdr->t_dflg |= t->t_dflg & 419 (F_NOFORK | F_NOINTERRUPT); 420 execute(t->t_dcdr, wanttty, NULL, NULL); 421 } 422 break; 423 424 case NODE_OR: 425 case NODE_AND: 426 if (t->t_dcar) { 427 t->t_dcar->t_dflg |= t->t_dflg & F_NOINTERRUPT; 428 execute(t->t_dcar, wanttty, NULL, NULL); 429 if ((getn(value(STRstatus)) == 0) != 430 (t->t_dtyp == NODE_AND)) 431 return; 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 /* 441 * Fall through for all breaks from switch 442 * 443 * If there will be no more executions of this command, flush all file 444 * descriptors. Places that turn on the F_REPEAT bit are responsible for 445 * doing donefds after the last re-execution 446 */ 447 if (didfds && !(t->t_dflg & F_REPEAT)) 448 donefds(); 449 } 450 451 static void 452 vffree(int i) 453 { 454 _exit(i); 455 } 456 457 /* 458 * Expand and glob the words after an i/o redirection. 459 * If more than one word is generated, then update the command vector. 460 * 461 * This is done differently in all the shells: 462 * 1. in the bourne shell and ksh globbing is not performed 463 * 2. Bash/csh say ambiguous 464 * 3. zsh does i/o to/from all the files 465 * 4. itcsh concatenates the words. 466 * 467 * I don't know what is best to do. I think that Ambiguous is better 468 * than restructuring the command vector, because the user can get 469 * unexpected results. In any case, the command vector restructuring 470 * code is present and the user can choose it by setting noambiguous 471 */ 472 static Char * 473 splicepipe(struct command *t, Char *cp) /* word after < or > */ 474 { 475 Char *blk[2]; 476 477 if (adrof(STRnoambiguous)) { 478 Char **pv; 479 480 blk[0] = Dfix1(cp); /* expand $ */ 481 blk[1] = NULL; 482 483 gflag = 0, tglob(blk); 484 if (gflag) { 485 pv = globall(blk); 486 if (pv == NULL) { 487 setname(vis_str(blk[0])); 488 free(blk[0]); 489 stderror(ERR_NAME | ERR_NOMATCH); 490 } 491 gargv = NULL; 492 if (pv[1] != NULL) { /* we need to fix the command vector */ 493 Char **av = blkspl(t->t_dcom, &pv[1]); 494 free(t->t_dcom); 495 t->t_dcom = av; 496 } 497 free(blk[0]); 498 blk[0] = pv[0]; 499 free(pv); 500 } 501 } 502 else { 503 blk[0] = globone(blk[1] = Dfix1(cp), G_ERROR); 504 free(blk[1]); 505 } 506 return(blk[0]); 507 } 508 509 /* 510 * Perform io redirection. 511 * We may or maynot be forked here. 512 */ 513 static void 514 doio(struct command *t, int *pipein, int *pipeout) 515 { 516 int fd; 517 Char *cp; 518 int flags = t->t_dflg; 519 520 if (didfds || (flags & F_REPEAT)) 521 return; 522 if ((flags & F_READ) == 0) {/* F_READ already done */ 523 if (t->t_dlef) { 524 char tmp[PATH_MAX]; 525 526 /* 527 * so < /dev/std{in,out,err} work 528 */ 529 (void) dcopy(SHIN, 0); 530 (void) dcopy(SHOUT, 1); 531 (void) dcopy(SHERR, 2); 532 cp = splicepipe(t, t->t_dlef); 533 strlcpy(tmp, short2str(cp), sizeof tmp); 534 free(cp); 535 if ((fd = open(tmp, O_RDONLY)) == -1) 536 stderror(ERR_SYSTEM, tmp, strerror(errno)); 537 (void) dmove(fd, 0); 538 } 539 else if (flags & F_PIPEIN) { 540 (void) dup2(pipein[0], 0); 541 (void) close(pipein[0]); 542 (void) close(pipein[1]); 543 } 544 else if ((flags & F_NOINTERRUPT) && tpgrp == -1) { 545 (void) close(0); 546 (void) open(_PATH_DEVNULL, O_RDONLY); 547 } 548 else { 549 (void) dup2(OLDSTD, 0); 550 } 551 } 552 if (t->t_drit) { 553 char tmp[PATH_MAX]; 554 555 cp = splicepipe(t, t->t_drit); 556 strlcpy(tmp, short2str(cp), sizeof tmp); 557 free(cp); 558 /* 559 * so > /dev/std{out,err} work 560 */ 561 (void) dcopy(SHOUT, 1); 562 (void) dcopy(SHERR, 2); 563 if ((flags & F_APPEND) && 564 (fd = open(tmp, O_WRONLY | O_APPEND)) >= 0); 565 else { 566 if (!(flags & F_OVERWRITE) && adrof(STRnoclobber)) { 567 if (flags & F_APPEND) 568 stderror(ERR_SYSTEM, tmp, strerror(errno)); 569 chkclob(tmp); 570 } 571 if ((fd = open(tmp, O_WRONLY | O_CREAT | O_TRUNC, 0666)) == -1) 572 stderror(ERR_SYSTEM, tmp, strerror(errno)); 573 } 574 (void) dmove(fd, 1); 575 } 576 else if (flags & F_PIPEOUT) { 577 (void) dup2(pipeout[1], 1); 578 } 579 else { 580 (void) dup2(SHOUT, 1); 581 } 582 583 if (flags & F_STDERR) { 584 (void) dup2(1, 2); 585 } 586 else { 587 (void) dup2(SHERR, 2); 588 } 589 didfds = 1; 590 } 591 592 void 593 mypipe(int *pv) 594 { 595 596 if (pipe(pv) == -1) 597 goto oops; 598 pv[0] = dmove(pv[0], -1); 599 pv[1] = dmove(pv[1], -1); 600 if (pv[0] >= 0 && pv[1] >= 0) 601 return; 602 oops: 603 stderror(ERR_PIPE); 604 } 605 606 static void 607 chkclob(char *cp) 608 { 609 struct stat stb; 610 611 if (stat(cp, &stb) == -1) 612 return; 613 if (S_ISCHR(stb.st_mode)) 614 return; 615 stderror(ERR_EXISTS, cp); 616 } 617