jobs.c revision 1.4
1 /*- 2 * Copyright (c) 1991 The Regents of the University of California. 3 * All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Kenneth Almquist. 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 static char sccsid[] = "@(#)jobs.c 5.1 (Berkeley) 3/7/91"; 39 static char rcsid[] = "$Header: /tank/opengrok/rsync2/NetBSD/src/bin/sh/jobs.c,v 1.4 1993/04/26 06:09:17 dpassage Exp $"; 40 #endif /* not lint */ 41 42 #include "shell.h" 43 #if JOBS 44 #include "sgtty.h" 45 #undef CEOF /* syntax.h redefines this */ 46 #endif 47 #include "main.h" 48 #include "parser.h" 49 #include "nodes.h" 50 #include "jobs.h" 51 #include "options.h" 52 #include "trap.h" 53 #include "signames.h" 54 #include "syntax.h" 55 #include "input.h" 56 #include "output.h" 57 #include "memalloc.h" 58 #include "error.h" 59 #include "mystring.h" 60 #include <fcntl.h> 61 #include <signal.h> 62 #include <errno.h> 63 #ifdef BSD 64 #include <sys/types.h> 65 #include <sys/wait.h> 66 #include <sys/time.h> 67 #include <sys/resource.h> 68 #endif 69 70 71 72 struct job *jobtab; /* array of jobs */ 73 int njobs; /* size of array */ 74 MKINIT short backgndpid = -1; /* pid of last background process */ 75 #if JOBS 76 int initialpgrp; /* pgrp of shell on invocation */ 77 short curjob; /* current job */ 78 #endif 79 80 #ifdef __STDC__ 81 STATIC void restartjob(struct job *); 82 STATIC struct job *getjob(char *); 83 STATIC void freejob(struct job *); 84 STATIC int procrunning(int); 85 STATIC int dowait(int, struct job *); 86 STATIC int waitproc(int, int *); 87 STATIC char *commandtext(union node *); 88 #else 89 STATIC void restartjob(); 90 STATIC struct job *getjob(); 91 STATIC void freejob(); 92 STATIC int procrunning(); 93 STATIC int dowait(); 94 STATIC int waitproc(); 95 STATIC char *commandtext(); 96 #endif 97 98 99 100 #if JOBS 101 /* 102 * Turn job control on and off. 103 * 104 * Note: This code assumes that the third arg to ioctl is a character 105 * pointer, which is true on Berkeley systems but not System V. Since 106 * System V doesn't have job control yet, this isn't a problem now. 107 */ 108 109 MKINIT int jobctl; 110 111 void 112 setjobctl(on) { 113 int ldisc; 114 115 if (on == jobctl || rootshell == 0) 116 return; 117 if (on) { 118 do { /* while we are in the background */ 119 if (ioctl(2, TIOCGPGRP, (char *)&initialpgrp) < 0) { 120 out2str("ash: can't access tty; job control turned off\n"); 121 jflag = 0; 122 return; 123 } 124 if (initialpgrp == -1) 125 initialpgrp = getpgrp(0); 126 else if (initialpgrp != getpgrp(0)) { 127 killpg(initialpgrp, SIGTTIN); 128 continue; 129 } 130 } while (0); 131 if (ioctl(2, TIOCGETD, (char *)&ldisc) < 0 || ldisc != NTTYDISC) { 132 out2str("ash: need new tty driver to run job control; job control turned off\n"); 133 jflag = 0; 134 return; 135 } 136 setsignal(SIGTSTP); 137 setsignal(SIGTTOU); 138 setpgrp(0, rootpid); 139 ioctl(2, TIOCSPGRP, (char *)&rootpid); 140 } else { /* turning job control off */ 141 setpgrp(0, initialpgrp); 142 ioctl(2, TIOCSPGRP, (char *)&initialpgrp); 143 setsignal(SIGTSTP); 144 setsignal(SIGTTOU); 145 } 146 jobctl = on; 147 } 148 #endif 149 150 151 #ifdef mkinit 152 153 SHELLPROC { 154 backgndpid = -1; 155 #if JOBS 156 jobctl = 0; 157 #endif 158 } 159 160 #endif 161 162 163 164 #if JOBS 165 fgcmd(argc, argv) char **argv; { 166 struct job *jp; 167 int pgrp; 168 int status; 169 170 jp = getjob(argv[1]); 171 if (jp->jobctl == 0) 172 error("job not created under job control"); 173 pgrp = jp->ps[0].pid; 174 ioctl(2, TIOCSPGRP, (char *)&pgrp); 175 restartjob(jp); 176 INTOFF; 177 status = waitforjob(jp); 178 INTON; 179 return status; 180 } 181 182 183 bgcmd(argc, argv) char **argv; { 184 struct job *jp; 185 186 do { 187 jp = getjob(*++argv); 188 if (jp->jobctl == 0) 189 error("job not created under job control"); 190 restartjob(jp); 191 } while (--argc > 1); 192 return 0; 193 } 194 195 196 STATIC void 197 restartjob(jp) 198 struct job *jp; 199 { 200 struct procstat *ps; 201 int i; 202 203 if (jp->state == JOBDONE) 204 return; 205 INTOFF; 206 killpg(jp->ps[0].pid, SIGCONT); 207 for (ps = jp->ps, i = jp->nprocs ; --i >= 0 ; ps++) { 208 if ((ps->status & 0377) == 0177) { 209 ps->status = -1; 210 jp->state = 0; 211 } 212 } 213 INTON; 214 } 215 #endif 216 217 218 int 219 jobscmd(argc, argv) char **argv; { 220 showjobs(0); 221 return 0; 222 } 223 224 225 /* 226 * Print a list of jobs. If "change" is nonzero, only print jobs whose 227 * statuses have changed since the last call to showjobs. 228 * 229 * If the shell is interrupted in the process of creating a job, the 230 * result may be a job structure containing zero processes. Such structures 231 * will be freed here. 232 */ 233 234 void 235 showjobs(change) { 236 int jobno; 237 int procno; 238 int i; 239 struct job *jp; 240 struct procstat *ps; 241 int col; 242 char s[64]; 243 244 TRACE(("showjobs(%d) called\n", change)); 245 while (dowait(0, (struct job *)NULL) > 0); 246 for (jobno = 1, jp = jobtab ; jobno <= njobs ; jobno++, jp++) { 247 if (! jp->used) 248 continue; 249 if (jp->nprocs == 0) { 250 freejob(jp); 251 continue; 252 } 253 if (change && ! jp->changed) 254 continue; 255 procno = jp->nprocs; 256 for (ps = jp->ps ; ; ps++) { /* for each process */ 257 if (ps == jp->ps) 258 fmtstr(s, 64, "[%d] %d ", jobno, ps->pid); 259 else 260 fmtstr(s, 64, " %d ", ps->pid); 261 out1str(s); 262 col = strlen(s); 263 s[0] = '\0'; 264 if (ps->status == -1) { 265 /* don't print anything */ 266 } else if ((ps->status & 0xFF) == 0) { 267 fmtstr(s, 64, "Exit %d", ps->status >> 8); 268 } else { 269 i = ps->status; 270 #if JOBS 271 if ((i & 0xFF) == 0177) 272 i >>= 8; 273 #endif 274 if ((i & 0x7F) <= MAXSIG && sigmesg[i & 0x7F]) 275 scopy(sigmesg[i & 0x7F], s); 276 else 277 fmtstr(s, 64, "Signal %d", i & 0x7F); 278 if (i & 0x80) 279 strcat(s, " (core dumped)"); 280 } 281 out1str(s); 282 col += strlen(s); 283 do { 284 out1c(' '); 285 col++; 286 } while (col < 30); 287 out1str(ps->cmd); 288 out1c('\n'); 289 if (--procno <= 0) 290 break; 291 } 292 jp->changed = 0; 293 if (jp->state == JOBDONE) { 294 freejob(jp); 295 } 296 } 297 } 298 299 300 /* 301 * Mark a job structure as unused. 302 */ 303 304 STATIC void 305 freejob(jp) 306 struct job *jp; 307 { 308 struct procstat *ps; 309 int i; 310 311 INTOFF; 312 for (i = jp->nprocs, ps = jp->ps ; --i >= 0 ; ps++) { 313 if (ps->cmd != nullstr) 314 ckfree(ps->cmd); 315 } 316 if (jp->ps != &jp->ps0) 317 ckfree(jp->ps); 318 jp->used = 0; 319 #if JOBS 320 if (curjob == jp - jobtab + 1) 321 curjob = 0; 322 #endif 323 INTON; 324 } 325 326 327 328 int 329 waitcmd(argc, argv) char **argv; { 330 struct job *job; 331 int status; 332 struct job *jp; 333 334 if (argc > 1) { 335 job = getjob(argv[1]); 336 } else { 337 job = NULL; 338 } 339 for (;;) { /* loop until process terminated or stopped */ 340 if (job != NULL) { 341 if (job->state) { 342 status = job->ps[job->nprocs - 1].status; 343 if ((status & 0xFF) == 0) 344 status = status >> 8 & 0xFF; 345 #if JOBS 346 else if ((status & 0xFF) == 0177) 347 status = (status >> 8 & 0x7F) + 128; 348 #endif 349 else 350 status = (status & 0x7F) + 128; 351 if (! iflag) 352 freejob(job); 353 return status; 354 } 355 } else { 356 for (jp = jobtab ; ; jp++) { 357 if (jp >= jobtab + njobs) { /* no running procs */ 358 return 0; 359 } 360 if (jp->used && jp->state == 0) 361 break; 362 } 363 } 364 dowait(1, (struct job *)NULL); 365 } 366 } 367 368 369 370 jobidcmd(argc, argv) char **argv; { 371 struct job *jp; 372 int i; 373 374 jp = getjob(argv[1]); 375 for (i = 0 ; i < jp->nprocs ; ) { 376 out1fmt("%d", jp->ps[i].pid); 377 out1c(++i < jp->nprocs? ' ' : '\n'); 378 } 379 return 0; 380 } 381 382 383 384 /* 385 * Convert a job name to a job structure. 386 */ 387 388 STATIC struct job * 389 getjob(name) 390 char *name; 391 { 392 int jobno; 393 register struct job *jp; 394 int pid; 395 int i; 396 397 if (name == NULL) { 398 #if JOBS 399 currentjob: 400 if ((jobno = curjob) == 0 || jobtab[jobno - 1].used == 0) 401 error("No current job"); 402 return &jobtab[jobno - 1]; 403 #else 404 error("No current job"); 405 #endif 406 } else if (name[0] == '%') { 407 if (is_digit(name[1])) { 408 jobno = number(name + 1); 409 if (jobno > 0 && jobno <= njobs 410 && jobtab[jobno - 1].used != 0) 411 return &jobtab[jobno - 1]; 412 #if JOBS 413 } else if (name[1] == '%' && name[2] == '\0') { 414 goto currentjob; 415 #endif 416 } else { 417 register struct job *found = NULL; 418 for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) { 419 if (jp->used && jp->nprocs > 0 420 && prefix(name + 1, jp->ps[0].cmd)) { 421 if (found) 422 error("%s: ambiguous", name); 423 found = jp; 424 } 425 } 426 if (found) 427 return found; 428 } 429 } else if (is_number(name)) { 430 pid = number(name); 431 for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) { 432 if (jp->used && jp->nprocs > 0 433 && jp->ps[jp->nprocs - 1].pid == pid) 434 return jp; 435 } 436 } 437 error("No such job: %s", name); 438 } 439 440 441 442 /* 443 * Return a new job structure, 444 */ 445 446 struct job * 447 makejob(node, nprocs) 448 union node *node; 449 { 450 int i; 451 struct job *jp; 452 453 for (i = njobs, jp = jobtab ; ; jp++) { 454 if (--i < 0) { 455 INTOFF; 456 if (njobs == 0) { 457 jobtab = ckmalloc(4 * sizeof jobtab[0]); 458 } else { 459 jp = ckmalloc((njobs + 4) * sizeof jobtab[0]); 460 bcopy(jobtab, jp, njobs * sizeof jp[0]); 461 ckfree(jobtab); 462 jobtab = jp; 463 } 464 jp = jobtab + njobs; 465 for (i = 4 ; --i >= 0 ; jobtab[njobs++].used = 0); 466 INTON; 467 break; 468 } 469 if (jp->used == 0) 470 break; 471 } 472 INTOFF; 473 jp->state = 0; 474 jp->used = 1; 475 jp->changed = 0; 476 jp->nprocs = 0; 477 #if JOBS 478 jp->jobctl = jobctl; 479 #endif 480 if (nprocs > 1) { 481 jp->ps = ckmalloc(nprocs * sizeof (struct procstat)); 482 } else { 483 jp->ps = &jp->ps0; 484 } 485 INTON; 486 TRACE(("makejob(0x%x, %d) returns %%%d\n", (int)node, nprocs, jp - jobtab + 1)); 487 return jp; 488 } 489 490 491 /* 492 * Fork of a subshell. If we are doing job control, give the subshell its 493 * own process group. Jp is a job structure that the job is to be added to. 494 * N is the command that will be evaluated by the child. Both jp and n may 495 * be NULL. The mode parameter can be one of the following: 496 * FORK_FG - Fork off a foreground process. 497 * FORK_BG - Fork off a background process. 498 * FORK_NOJOB - Like FORK_FG, but don't give the process its own 499 * process group even if job control is on. 500 * 501 * When job control is turned off, background processes have their standard 502 * input redirected to /dev/null (except for the second and later processes 503 * in a pipeline). 504 */ 505 506 int 507 forkshell(jp, n, mode) 508 union node *n; 509 struct job *jp; 510 { 511 int pid; 512 int pgrp; 513 514 TRACE(("forkshell(%%%d, 0x%x, %d) called\n", jp - jobtab, (int)n, mode)); 515 INTOFF; 516 pid = fork(); 517 if (pid == -1) { 518 TRACE(("Fork failed, errno=%d\n", errno)); 519 INTON; 520 error("Cannot fork"); 521 } 522 if (pid == 0) { 523 struct job *p; 524 int wasroot; 525 int i; 526 527 TRACE(("Child shell %d\n", getpid())); 528 wasroot = rootshell; 529 rootshell = 0; 530 for (i = njobs, p = jobtab ; --i >= 0 ; p++) 531 if (p->used) 532 freejob(p); 533 closescript(); 534 INTON; 535 clear_traps(); 536 #if JOBS 537 jobctl = 0; /* do job control only in root shell */ 538 if (wasroot && mode != FORK_NOJOB && jflag) { 539 if (jp == NULL || jp->nprocs == 0) 540 pgrp = getpid(); 541 else 542 pgrp = jp->ps[0].pid; 543 setpgrp(0, pgrp); 544 if (mode == FORK_FG) { 545 /*** this causes superfluous TIOCSPGRPS ***/ 546 if (ioctl(2, TIOCSPGRP, (char *)&pgrp) < 0) 547 error("TIOCSPGRP failed, errno=%d\n", errno); 548 } 549 setsignal(SIGTSTP); 550 setsignal(SIGTTOU); 551 } else if (mode == FORK_BG) { 552 ignoresig(SIGINT); 553 ignoresig(SIGQUIT); 554 if (jp == NULL || jp->nprocs == 0) { 555 close(0); 556 if (open("/dev/null", O_RDONLY) != 0) 557 error("Can't open /dev/null"); 558 } 559 } 560 #else 561 if (mode == FORK_BG) { 562 ignoresig(SIGINT); 563 ignoresig(SIGQUIT); 564 if (jp == NULL || jp->nprocs == 0) { 565 close(0); 566 if (open("/dev/null", O_RDONLY) != 0) 567 error("Can't open /dev/null"); 568 } 569 } 570 #endif 571 if (wasroot && iflag) { 572 setsignal(SIGINT); 573 setsignal(SIGQUIT); 574 setsignal(SIGTERM); 575 } 576 return pid; 577 } 578 if (rootshell && mode != FORK_NOJOB && jflag) { 579 if (jp == NULL || jp->nprocs == 0) 580 pgrp = pid; 581 else 582 pgrp = jp->ps[0].pid; 583 setpgrp(pid, pgrp); 584 } 585 if (mode == FORK_BG) 586 backgndpid = pid; /* set $! */ 587 if (jp) { 588 struct procstat *ps = &jp->ps[jp->nprocs++]; 589 ps->pid = pid; 590 ps->status = -1; 591 ps->cmd = nullstr; 592 if (iflag && rootshell && n) 593 ps->cmd = commandtext(n); 594 } 595 INTON; 596 TRACE(("In parent shell: child = %d\n", pid)); 597 return pid; 598 } 599 600 601 602 /* 603 * Wait for job to finish. 604 * 605 * Under job control we have the problem that while a child process is 606 * running interrupts generated by the user are sent to the child but not 607 * to the shell. This means that an infinite loop started by an inter- 608 * active user may be hard to kill. With job control turned off, an 609 * interactive user may place an interactive program inside a loop. If 610 * the interactive program catches interrupts, the user doesn't want 611 * these interrupts to also abort the loop. The approach we take here 612 * is to have the shell ignore interrupt signals while waiting for a 613 * forground process to terminate, and then send itself an interrupt 614 * signal if the child process was terminated by an interrupt signal. 615 * Unfortunately, some programs want to do a bit of cleanup and then 616 * exit on interrupt; unless these processes terminate themselves by 617 * sending a signal to themselves (instead of calling exit) they will 618 * confuse this approach. 619 */ 620 621 int 622 waitforjob(jp) 623 register struct job *jp; 624 { 625 #if JOBS 626 int mypgrp = getpgrp(0); 627 #endif 628 int status; 629 int st; 630 631 INTOFF; 632 TRACE(("waitforjob(%%%d) called\n", jp - jobtab + 1)); 633 while (jp->state == 0) { 634 dowait(1, jp); 635 } 636 #if JOBS 637 if (jp->jobctl) { 638 if (ioctl(2, TIOCSPGRP, (char *)&mypgrp) < 0) 639 error("TIOCSPGRP failed, errno=%d\n", errno); 640 } 641 if (jp->state == JOBSTOPPED) 642 curjob = jp - jobtab + 1; 643 #endif 644 status = jp->ps[jp->nprocs - 1].status; 645 /* convert to 8 bits */ 646 if ((status & 0xFF) == 0) 647 st = status >> 8 & 0xFF; 648 #if JOBS 649 else if ((status & 0xFF) == 0177) 650 st = (status >> 8 & 0x7F) + 128; 651 #endif 652 else 653 st = (status & 0x7F) + 128; 654 if (! JOBS || jp->state == JOBDONE) 655 freejob(jp); 656 CLEAR_PENDING_INT; 657 if ((status & 0x7F) == SIGINT) 658 kill(getpid(), SIGINT); 659 INTON; 660 return st; 661 } 662 663 664 665 /* 666 * Wait for a process to terminate. 667 */ 668 669 STATIC int 670 dowait(block, job) 671 struct job *job; 672 { 673 int pid; 674 int status; 675 struct procstat *sp; 676 struct job *jp; 677 struct job *thisjob; 678 int done; 679 int stopped; 680 int core; 681 682 TRACE(("dowait(%d) called\n", block)); 683 do { 684 pid = waitproc(block, &status); 685 TRACE(("wait returns %d, status=%d\n", pid, status)); 686 } while (pid == -1 && errno == EINTR); 687 if (pid <= 0) 688 return pid; 689 INTOFF; 690 thisjob = NULL; 691 for (jp = jobtab ; jp < jobtab + njobs ; jp++) { 692 if (jp->used) { 693 done = 1; 694 stopped = 1; 695 for (sp = jp->ps ; sp < jp->ps + jp->nprocs ; sp++) { 696 if (sp->pid == -1) 697 continue; 698 if (sp->pid == pid) { 699 TRACE(("Changin status of proc %d from 0x%x to 0x%x\n", pid, sp->status, status)); 700 sp->status = status; 701 thisjob = jp; 702 } 703 if (sp->status == -1) 704 stopped = 0; 705 else if ((sp->status & 0377) == 0177) 706 done = 0; 707 } 708 if (stopped) { /* stopped or done */ 709 int state = done? JOBDONE : JOBSTOPPED; 710 if (jp->state != state) { 711 TRACE(("Job %d: changing state from %d to %d\n", jp - jobtab + 1, jp->state, state)); 712 jp->state = state; 713 #if JOBS 714 if (done && curjob == jp - jobtab + 1) 715 curjob = 0; /* no current job */ 716 #endif 717 } 718 } 719 } 720 } 721 INTON; 722 if (! rootshell || ! iflag || (job && thisjob == job)) { 723 #if JOBS 724 if ((status & 0xFF) == 0177) 725 status >>= 8; 726 #endif 727 core = status & 0x80; 728 status &= 0x7F; 729 if (status != 0 && status != SIGINT && status != SIGPIPE) { 730 if (thisjob != job) 731 outfmt(out2, "%d: ", pid); 732 #if JOBS 733 if (status == SIGTSTP && rootshell && iflag) 734 outfmt(out2, "%%%d ", job - jobtab + 1); 735 #endif 736 if (status <= MAXSIG && sigmesg[status]) 737 out2str(sigmesg[status]); 738 else 739 outfmt(out2, "Signal %d", status); 740 if (core) 741 out2str(" - core dumped"); 742 out2c('\n'); 743 flushout(&errout); 744 } else { 745 TRACE(("Not printing status: status=%d\n", status)); 746 } 747 } else { 748 TRACE(("Not printing status, rootshell=%d, job=0x%x\n", rootshell, job)); 749 if (thisjob) 750 thisjob->changed = 1; 751 } 752 return pid; 753 } 754 755 756 757 /* 758 * Do a wait system call. If job control is compiled in, we accept 759 * stopped processes. If block is zero, we return a value of zero 760 * rather than blocking. 761 * 762 * System V doesn't have a non-blocking wait system call. It does 763 * have a SIGCLD signal that is sent to a process when one of it's 764 * children dies. The obvious way to use SIGCLD would be to install 765 * a handler for SIGCLD which simply bumped a counter when a SIGCLD 766 * was received, and have waitproc bump another counter when it got 767 * the status of a process. Waitproc would then know that a wait 768 * system call would not block if the two counters were different. 769 * This approach doesn't work because if a process has children that 770 * have not been waited for, System V will send it a SIGCLD when it 771 * installs a signal handler for SIGCLD. What this means is that when 772 * a child exits, the shell will be sent SIGCLD signals continuously 773 * until is runs out of stack space, unless it does a wait call before 774 * restoring the signal handler. The code below takes advantage of 775 * this (mis)feature by installing a signal handler for SIGCLD and 776 * then checking to see whether it was called. If there are any 777 * children to be waited for, it will be. 778 * 779 * If neither SYSV nor BSD is defined, we don't implement nonblocking 780 * waits at all. In this case, the user will not be informed when 781 * a background process until the next time she runs a real program 782 * (as opposed to running a builtin command or just typing return), 783 * and the jobs command may give out of date information. 784 */ 785 786 #ifdef SYSV 787 STATIC int gotsigchild; 788 789 STATIC int onsigchild() { 790 gotsigchild = 1; 791 } 792 #endif 793 794 795 STATIC int 796 waitproc(block, status) 797 int *status; 798 { 799 #ifdef BSD 800 int flags; 801 802 #if JOBS 803 flags = WUNTRACED; 804 #else 805 flags = 0; 806 #endif 807 if (block == 0) 808 flags |= WNOHANG; 809 return wait3((int *)status, flags, (struct rusage *)NULL); 810 #else 811 #ifdef SYSV 812 int (*save)(); 813 814 if (block == 0) { 815 gotsigchild = 0; 816 save = signal(SIGCLD, onsigchild); 817 signal(SIGCLD, save); 818 if (gotsigchild == 0) 819 return 0; 820 } 821 return wait(status); 822 #else 823 if (block == 0) 824 return 0; 825 return wait(status); 826 #endif 827 #endif 828 } 829 830 831 832 /* 833 * Return a string identifying a command (to be printed by the 834 * jobs command. 835 */ 836 837 STATIC char *cmdnextc; 838 STATIC int cmdnleft; 839 STATIC void cmdtxt(), cmdputs(); 840 841 STATIC char * 842 commandtext(n) 843 union node *n; 844 { 845 char *name; 846 847 cmdnextc = name = ckmalloc(50); 848 cmdnleft = 50 - 4; 849 cmdtxt(n); 850 *cmdnextc = '\0'; 851 return name; 852 } 853 854 855 STATIC void 856 cmdtxt(n) 857 union node *n; 858 { 859 union node *np; 860 struct nodelist *lp; 861 char *p; 862 int i; 863 char s[2]; 864 865 switch (n->type) { 866 case NSEMI: 867 cmdtxt(n->nbinary.ch1); 868 cmdputs("; "); 869 cmdtxt(n->nbinary.ch2); 870 break; 871 case NAND: 872 cmdtxt(n->nbinary.ch1); 873 cmdputs(" && "); 874 cmdtxt(n->nbinary.ch2); 875 break; 876 case NOR: 877 cmdtxt(n->nbinary.ch1); 878 cmdputs(" || "); 879 cmdtxt(n->nbinary.ch2); 880 break; 881 case NPIPE: 882 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) { 883 cmdtxt(lp->n); 884 if (lp->next) 885 cmdputs(" | "); 886 } 887 break; 888 case NSUBSHELL: 889 cmdputs("("); 890 cmdtxt(n->nredir.n); 891 cmdputs(")"); 892 break; 893 case NREDIR: 894 case NBACKGND: 895 cmdtxt(n->nredir.n); 896 break; 897 case NIF: 898 cmdputs("if "); 899 cmdtxt(n->nif.test); 900 cmdputs("; then "); 901 cmdtxt(n->nif.ifpart); 902 cmdputs("..."); 903 break; 904 case NWHILE: 905 cmdputs("while "); 906 goto until; 907 case NUNTIL: 908 cmdputs("until "); 909 until: 910 cmdtxt(n->nbinary.ch1); 911 cmdputs("; do "); 912 cmdtxt(n->nbinary.ch2); 913 cmdputs("; done"); 914 break; 915 case NFOR: 916 cmdputs("for "); 917 cmdputs(n->nfor.var); 918 cmdputs(" in ..."); 919 break; 920 case NCASE: 921 cmdputs("case "); 922 cmdputs(n->ncase.expr->narg.text); 923 cmdputs(" in ..."); 924 break; 925 case NDEFUN: 926 cmdputs(n->narg.text); 927 cmdputs("() ..."); 928 break; 929 case NCMD: 930 for (np = n->ncmd.args ; np ; np = np->narg.next) { 931 cmdtxt(np); 932 if (np->narg.next) 933 cmdputs(" "); 934 } 935 for (np = n->ncmd.redirect ; np ; np = np->nfile.next) { 936 cmdputs(" "); 937 cmdtxt(np); 938 } 939 break; 940 case NARG: 941 cmdputs(n->narg.text); 942 break; 943 case NTO: 944 p = ">"; i = 1; goto redir; 945 case NAPPEND: 946 p = ">>"; i = 1; goto redir; 947 case NTOFD: 948 p = ">&"; i = 1; goto redir; 949 case NFROM: 950 p = "<"; i = 0; goto redir; 951 case NFROMFD: 952 p = "<&"; i = 0; goto redir; 953 redir: 954 if (n->nfile.fd != i) { 955 s[0] = n->nfile.fd + '0'; 956 s[1] = '\0'; 957 cmdputs(s); 958 } 959 cmdputs(p); 960 if (n->type == NTOFD || n->type == NFROMFD) { 961 s[0] = n->ndup.dupfd + '0'; 962 s[1] = '\0'; 963 cmdputs(s); 964 } else { 965 cmdtxt(n->nfile.fname); 966 } 967 break; 968 case NHERE: 969 case NXHERE: 970 cmdputs("<<..."); 971 break; 972 default: 973 cmdputs("???"); 974 break; 975 } 976 } 977 978 979 980 STATIC void 981 cmdputs(s) 982 char *s; 983 { 984 register char *p, *q; 985 register char c; 986 int subtype = 0; 987 988 if (cmdnleft <= 0) 989 return; 990 p = s; 991 q = cmdnextc; 992 while ((c = *p++) != '\0') { 993 if (c == CTLESC) 994 *q++ = *p++; 995 else if (c == CTLVAR) { 996 *q++ = '$'; 997 if (--cmdnleft > 0) 998 *q++ = '{'; 999 subtype = *p++; 1000 } else if (c == '=' && subtype != 0) { 1001 *q++ = "}-+?="[(subtype & VSTYPE) - VSNORMAL]; 1002 subtype = 0; 1003 } else if (c == CTLENDVAR) { 1004 *q++ = '}'; 1005 } else if (c == CTLBACKQ | c == CTLBACKQ+CTLQUOTE) 1006 cmdnleft++; /* ignore it */ 1007 else 1008 *q++ = c; 1009 if (--cmdnleft <= 0) { 1010 *q++ = '.'; 1011 *q++ = '.'; 1012 *q++ = '.'; 1013 break; 1014 } 1015 } 1016 cmdnextc = q; 1017 } 1018
Indexes created Thu Oct 23 22:10:10 GMT 2025