bin/sh/jobs.c

   1 /*-
   2  * Copyright (c) 1991, 1993
   3  *      The Regents of the University of California.  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  * 4. 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 #ifndef lint
  34 #if 0
  35 static char sccsid[] = "@(#)jobs.c      8.5 (Berkeley) 5/4/95";
  36 #endif
  37 #endif /* not lint */
  38 #include <sys/cdefs.h>
  39 __FBSDID("$FreeBSD$");
  40
  41 #include <sys/ioctl.h>
  42 #include <sys/param.h>
  43 #include <sys/resource.h>
  44 #include <sys/time.h>
  45 #include <sys/wait.h>
  46 #include <errno.h>
  47 #include <fcntl.h>
  48 #include <paths.h>
  49 #include <signal.h>
  50 #include <stddef.h>
  51 #include <stdlib.h>
  52 #include <unistd.h>
  53
  54 #include "shell.h"
  55 #if JOBS
  56 #include <termios.h>
  57 #undef CEOF                     /* syntax.h redefines this */
  58 #endif
  59 #include "redir.h"
  60 #include "exec.h"
  61 #include "show.h"
  62 #include "main.h"
  63 #include "parser.h"
  64 #include "nodes.h"
  65 #include "jobs.h"
  66 #include "options.h"
  67 #include "trap.h"
  68 #include "syntax.h"
  69 #include "input.h"
  70 #include "output.h"
  71 #include "memalloc.h"
  72 #include "error.h"
  73 #include "mystring.h"
  74 #include "var.h"
  75 #include "builtins.h"
  76
  77
  78 static struct job *jobtab;      /* array of jobs */
  79 static int njobs;               /* size of array */
  80 MKINIT pid_t backgndpid = -1;   /* pid of last background process */
  81 MKINIT struct job *bgjob = NULL; /* last background process */
  82 #if JOBS
  83 static struct job *jobmru;      /* most recently used job list */
  84 static pid_t initialpgrp;       /* pgrp of shell on invocation */
  85 #endif
  86 int in_waitcmd = 0;             /* are we in waitcmd()? */
  87 int in_dowait = 0;              /* are we in dowait()? */
  88 volatile sig_atomic_t breakwaitcmd = 0; /* should wait be terminated? */
  89 static int ttyfd = -1;
  90
  91 #if JOBS
  92 static void restartjob(struct job *);
  93 #endif
  94 static void freejob(struct job *);
  95 static struct job *getjob(char *);
  96 static pid_t dowait(int, struct job *);
  97 static pid_t waitproc(int, int *);
  98 static void checkzombies(void);
  99 static void cmdtxt(union node *);
 100 static void cmdputs(const char *);
 101 #if JOBS
 102 static void setcurjob(struct job *);
 103 static void deljob(struct job *);
 104 static struct job *getcurjob(struct job *);
 105 #endif
 106 static void printjobcmd(struct job *);
 107 static void showjob(struct job *, int);
 108
 109
 110 /*
 111  * Turn job control on and off.
 112  */
 113
 114 MKINIT int jobctl;
 115
 116 #if JOBS
 117 void
 118 setjobctl(int on)
 119 {
 120         int i;
 121
 122         if (on == jobctl || rootshell == 0)
 123                 return;
 124         if (on) {
 125                 if (ttyfd != -1)
 126                         close(ttyfd);
 127                 if ((ttyfd = open(_PATH_TTY, O_RDWR)) < 0) {
 128                         i = 0;
 129                         while (i <= 2 && !isatty(i))
 130                                 i++;
 131                         if (i > 2 || (ttyfd = fcntl(i, F_DUPFD, 10)) < 0)
 132                                 goto out;
 133                 }
 134                 if (ttyfd < 10) {
 135                         /*
 136                          * Keep our TTY file descriptor out of the way of
 137                          * the user's redirections.
 138                          */
 139                         if ((i = fcntl(ttyfd, F_DUPFD, 10)) < 0) {
 140                                 close(ttyfd);
 141                                 ttyfd = -1;
 142                                 goto out;
 143                         }
 144                         close(ttyfd);
 145                         ttyfd = i;
 146                 }
 147                 if (fcntl(ttyfd, F_SETFD, FD_CLOEXEC) < 0) {
 148                         close(ttyfd);
 149                         ttyfd = -1;
 150                         goto out;
 151                 }
 152                 do { /* while we are in the background */
 153                         initialpgrp = tcgetpgrp(ttyfd);
 154                         if (initialpgrp < 0) {
 155 out:                            out2fmt_flush("sh: can't access tty; job control turned off\n");
 156                                 mflag = 0;
 157                                 return;
 158                         }
 159                         if (initialpgrp != getpgrp()) {
 160                                 kill(0, SIGTTIN);
 161                                 continue;
 162                         }
 163                 } while (0);
 164                 setsignal(SIGTSTP);
 165                 setsignal(SIGTTOU);
 166                 setsignal(SIGTTIN);
 167                 setpgid(0, rootpid);
 168                 tcsetpgrp(ttyfd, rootpid);
 169         } else { /* turning job control off */
 170                 setpgid(0, initialpgrp);
 171                 tcsetpgrp(ttyfd, initialpgrp);
 172                 close(ttyfd);
 173                 ttyfd = -1;
 174                 setsignal(SIGTSTP);
 175                 setsignal(SIGTTOU);
 176                 setsignal(SIGTTIN);
 177         }
 178         jobctl = on;
 179 }
 180 #endif
 181
 182
 183 #if JOBS
 184 int
 185 fgcmd(int argc __unused, char **argv)
 186 {
 187         struct job *jp;
 188         pid_t pgrp;
 189         int status;
 190
 191         jp = getjob(argv[1]);
 192         if (jp->jobctl == 0)
 193                 error("job not created under job control");
 194         printjobcmd(jp);
 195         flushout(&output);
 196         pgrp = jp->ps[0].pid;
 197         tcsetpgrp(ttyfd, pgrp);
 198         restartjob(jp);
 199         jp->foreground = 1;
 200         INTOFF;
 201         status = waitforjob(jp, (int *)NULL);
 202         INTON;
 203         return status;
 204 }
 205
 206
 207 int
 208 bgcmd(int argc, char **argv)
 209 {
 210         struct job *jp;
 211
 212         do {
 213                 jp = getjob(*++argv);
 214                 if (jp->jobctl == 0)
 215                         error("job not created under job control");
 216                 if (jp->state == JOBDONE)
 217                         continue;
 218                 restartjob(jp);
 219                 jp->foreground = 0;
 220                 out1fmt("[%td] ", jp - jobtab + 1);
 221                 printjobcmd(jp);
 222         } while (--argc > 1);
 223         return 0;
 224 }
 225
 226
 227 static void
 228 restartjob(struct job *jp)
 229 {
 230         struct procstat *ps;
 231         int i;
 232
 233         if (jp->state == JOBDONE)
 234                 return;
 235         setcurjob(jp);
 236         INTOFF;
 237         kill(-jp->ps[0].pid, SIGCONT);
 238         for (ps = jp->ps, i = jp->nprocs ; --i >= 0 ; ps++) {
 239                 if (WIFSTOPPED(ps->status)) {
 240                         ps->status = -1;
 241                         jp->state = 0;
 242                 }
 243         }
 244         INTON;
 245 }
 246 #endif
 247
 248
 249 int
 250 jobscmd(int argc, char *argv[])
 251 {
 252         char *id;
 253         int ch, mode;
 254
 255         optind = optreset = 1;
 256         opterr = 0;
 257         mode = SHOWJOBS_DEFAULT;
 258         while ((ch = getopt(argc, argv, "lps")) != -1) {
 259                 switch (ch) {
 260                 case 'l':
 261                         mode = SHOWJOBS_VERBOSE;
 262                         break;
 263                 case 'p':
 264                         mode = SHOWJOBS_PGIDS;
 265                         break;
 266                 case 's':
 267                         mode = SHOWJOBS_PIDS;
 268                         break;
 269                 case '?':
 270                 default:
 271                         error("unknown option: -%c", optopt);
 272                 }
 273         }
 274         argc -= optind;
 275         argv += optind;
 276
 277         if (argc == 0)
 278                 showjobs(0, mode);
 279         else
 280                 while ((id = *argv++) != NULL)
 281                         showjob(getjob(id), mode);
 282
 283         return (0);
 284 }
 285
 286 static void
 287 printjobcmd(struct job *jp)
 288 {
 289         struct procstat *ps;
 290         int i;
 291
 292         for (ps = jp->ps, i = jp->nprocs ; --i >= 0 ; ps++) {
 293                 out1str(ps->cmd);
 294                 if (i > 0)
 295                         out1str(" | ");
 296         }
 297         out1c('\n');
 298 }
 299
 300 static void
 301 showjob(struct job *jp, int mode)
 302 {
 303         char s[64];
 304         char statestr[64];
 305         struct procstat *ps;
 306         struct job *j;
 307         int col, curr, i, jobno, prev, procno;
 308         char c;
 309
 310         procno = (mode == SHOWJOBS_PGIDS) ? 1 : jp->nprocs;
 311         jobno = jp - jobtab + 1;
 312         curr = prev = 0;
 313 #if JOBS
 314         if ((j = getcurjob(NULL)) != NULL) {
 315                 curr = j - jobtab + 1;
 316                 if ((j = getcurjob(j)) != NULL)
 317                         prev = j - jobtab + 1;
 318         }
 319 #endif
 320         ps = jp->ps + jp->nprocs - 1;
 321         if (jp->state == 0) {
 322                 strcpy(statestr, "Running");
 323 #if JOBS
 324         } else if (jp->state == JOBSTOPPED) {
 325                 while (!WIFSTOPPED(ps->status) && ps > jp->ps)
 326                         ps--;
 327                 if (WIFSTOPPED(ps->status))
 328                         i = WSTOPSIG(ps->status);
 329                 else
 330                         i = -1;
 331                 if (i > 0 && i < sys_nsig && sys_siglist[i])
 332                         strcpy(statestr, sys_siglist[i]);
 333                 else
 334                         strcpy(statestr, "Suspended");
 335 #endif
 336         } else if (WIFEXITED(ps->status)) {
 337                 if (WEXITSTATUS(ps->status) == 0)
 338                         strcpy(statestr, "Done");
 339                 else
 340                         fmtstr(statestr, 64, "Done(%d)",
 341                             WEXITSTATUS(ps->status));
 342         } else {
 343                 i = WTERMSIG(ps->status);
 344                 if (i > 0 && i < sys_nsig && sys_siglist[i])
 345                         strcpy(statestr, sys_siglist[i]);
 346                 else
 347                         fmtstr(statestr, 64, "Signal %d", i);
 348                 if (WCOREDUMP(ps->status))
 349                         strcat(statestr, " (core dumped)");
 350         }
 351
 352         for (ps = jp->ps ; ; ps++) {    /* for each process */
 353                 if (mode == SHOWJOBS_PIDS || mode == SHOWJOBS_PGIDS) {
 354                         out1fmt("%d\n", (int)ps->pid);
 355                         goto skip;
 356                 }
 357                 if (mode != SHOWJOBS_VERBOSE && ps != jp->ps)
 358                         goto skip;
 359                 if (jobno == curr && ps == jp->ps)
 360                         c = '+';
 361                 else if (jobno == prev && ps == jp->ps)
 362                         c = '-';
 363                 else
 364                         c = ' ';
 365                 if (ps == jp->ps)
 366                         fmtstr(s, 64, "[%d] %c ", jobno, c);
 367                 else
 368                         fmtstr(s, 64, "    %c ", c);
 369                 out1str(s);
 370                 col = strlen(s);
 371                 if (mode == SHOWJOBS_VERBOSE) {
 372                         fmtstr(s, 64, "%d ", (int)ps->pid);
 373                         out1str(s);
 374                         col += strlen(s);
 375                 }
 376                 if (ps == jp->ps) {
 377                         out1str(statestr);
 378                         col += strlen(statestr);
 379                 }
 380                 do {
 381                         out1c(' ');
 382                         col++;
 383                 } while (col < 30);
 384                 if (mode == SHOWJOBS_VERBOSE) {
 385                         out1str(ps->cmd);
 386                         out1c('\n');
 387                 } else
 388                         printjobcmd(jp);
 389 skip:           if (--procno <= 0)
 390                         break;
 391         }
 392 }
 393
 394 /*
 395  * Print a list of jobs.  If "change" is nonzero, only print jobs whose
 396  * statuses have changed since the last call to showjobs.
 397  *
 398  * If the shell is interrupted in the process of creating a job, the
 399  * result may be a job structure containing zero processes.  Such structures
 400  * will be freed here.
 401  */
 402
 403 void
 404 showjobs(int change, int mode)
 405 {
 406         int jobno;
 407         struct job *jp;
 408
 409         TRACE(("showjobs(%d) called\n", change));
 410         checkzombies();
 411         for (jobno = 1, jp = jobtab ; jobno <= njobs ; jobno++, jp++) {
 412                 if (! jp->used)
 413                         continue;
 414                 if (jp->nprocs == 0) {
 415                         freejob(jp);
 416                         continue;
 417                 }
 418                 if (change && ! jp->changed)
 419                         continue;
 420                 showjob(jp, mode);
 421                 jp->changed = 0;
 422                 /* Hack: discard jobs for which $! has not been referenced
 423                  * in interactive mode when they terminate.
 424                  */
 425                 if (jp->state == JOBDONE && !jp->remembered &&
 426                                 (iflag || jp != bgjob)) {
 427                         freejob(jp);
 428                 }
 429         }
 430 }
 431
 432
 433 /*
 434  * Mark a job structure as unused.
 435  */
 436
 437 static void
 438 freejob(struct job *jp)
 439 {
 440         struct procstat *ps;
 441         int i;
 442
 443         INTOFF;
 444         if (bgjob == jp)
 445                 bgjob = NULL;
 446         for (i = jp->nprocs, ps = jp->ps ; --i >= 0 ; ps++) {
 447                 if (ps->cmd != nullstr)
 448                         ckfree(ps->cmd);
 449         }
 450         if (jp->ps != &jp->ps0)
 451                 ckfree(jp->ps);
 452         jp->used = 0;
 453 #if JOBS
 454         deljob(jp);
 455 #endif
 456         INTON;
 457 }
 458
 459
 460
 461 int
 462 waitcmd(int argc, char **argv)
 463 {
 464         struct job *job;
 465         int status, retval;
 466         struct job *jp;
 467
 468         if (argc > 1) {
 469                 job = getjob(argv[1]);
 470         } else {
 471                 job = NULL;
 472         }
 473
 474         /*
 475          * Loop until a process is terminated or stopped, or a SIGINT is
 476          * received.
 477          */
 478
 479         in_waitcmd++;
 480         do {
 481                 if (job != NULL) {
 482                         if (job->state) {
 483                                 status = job->ps[job->nprocs - 1].status;
 484                                 if (WIFEXITED(status))
 485                                         retval = WEXITSTATUS(status);
 486 #if JOBS
 487                                 else if (WIFSTOPPED(status))
 488                                         retval = WSTOPSIG(status) + 128;
 489 #endif
 490                                 else
 491                                         retval = WTERMSIG(status) + 128;
 492                                 if (! iflag || ! job->changed)
 493                                         freejob(job);
 494                                 else {
 495                                         job->remembered = 0;
 496                                         if (job == bgjob)
 497                                                 bgjob = NULL;
 498                                 }
 499                                 in_waitcmd--;
 500                                 return retval;
 501                         }
 502                 } else {
 503                         for (jp = jobtab ; jp < jobtab + njobs; jp++)
 504                                 if (jp->used && jp->state == JOBDONE) {
 505                                         if (! iflag || ! jp->changed)
 506                                                 freejob(jp);
 507                                         else {
 508                                                 jp->remembered = 0;
 509                                                 if (jp == bgjob)
 510                                                         bgjob = NULL;
 511                                         }
 512                                 }
 513                         for (jp = jobtab ; ; jp++) {
 514                                 if (jp >= jobtab + njobs) {     /* no running procs */
 515                                         in_waitcmd--;
 516                                         return 0;
 517                                 }
 518                                 if (jp->used && jp->state == 0)
 519                                         break;
 520                         }
 521                 }
 522         } while (dowait(1, (struct job *)NULL) != -1);
 523         in_waitcmd--;
 524
 525         return 0;
 526 }
 527
 528
 529
 530 int
 531 jobidcmd(int argc __unused, char **argv)
 532 {
 533         struct job *jp;
 534         int i;
 535
 536         jp = getjob(argv[1]);
 537         for (i = 0 ; i < jp->nprocs ; ) {
 538                 out1fmt("%d", (int)jp->ps[i].pid);
 539                 out1c(++i < jp->nprocs? ' ' : '\n');
 540         }
 541         return 0;
 542 }
 543
 544
 545
 546 /*
 547  * Convert a job name to a job structure.
 548  */
 549
 550 static struct job *
 551 getjob(char *name)
 552 {
 553         int jobno;
 554         struct job *found, *jp;
 555         pid_t pid;
 556         int i;
 557
 558         if (name == NULL) {
 559 #if JOBS
 560 currentjob:     if ((jp = getcurjob(NULL)) == NULL)
 561                         error("No current job");
 562                 return (jp);
 563 #else
 564                 error("No current job");
 565 #endif
 566         } else if (name[0] == '%') {
 567                 if (is_digit(name[1])) {
 568                         jobno = number(name + 1);
 569                         if (jobno > 0 && jobno <= njobs
 570                          && jobtab[jobno - 1].used != 0)
 571                                 return &jobtab[jobno - 1];
 572 #if JOBS
 573                 } else if (name[1] == '%' && name[2] == '\0') {
 574                         goto currentjob;
 575                 } else if (name[1] == '+' && name[2] == '\0') {
 576                         goto currentjob;
 577                 } else if (name[1] == '-' && name[2] == '\0') {
 578                         if ((jp = getcurjob(NULL)) == NULL ||
 579                             (jp = getcurjob(jp)) == NULL)
 580                                 error("No previous job");
 581                         return (jp);
 582 #endif
 583                 } else if (name[1] == '?') {
 584                         found = NULL;
 585                         for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
 586                                 if (jp->used && jp->nprocs > 0
 587                                  && strstr(jp->ps[0].cmd, name + 2) != NULL) {
 588                                         if (found)
 589                                                 error("%s: ambiguous", name);
 590                                         found = jp;
 591                                 }
 592                         }
 593                         if (found != NULL)
 594                                 return (found);
 595                 } else {
 596                         found = NULL;
 597                         for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
 598                                 if (jp->used && jp->nprocs > 0
 599                                  && prefix(name + 1, jp->ps[0].cmd)) {
 600                                         if (found)
 601                                                 error("%s: ambiguous", name);
 602                                         found = jp;
 603                                 }
 604                         }
 605                         if (found)
 606                                 return found;
 607                 }
 608         } else if (is_number(name)) {
 609                 pid = (pid_t)number(name);
 610                 for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
 611                         if (jp->used && jp->nprocs > 0
 612                          && jp->ps[jp->nprocs - 1].pid == pid)
 613                                 return jp;
 614                 }
 615         }
 616         error("No such job: %s", name);
 617         /*NOTREACHED*/
 618         return NULL;
 619 }
 620
 621
 622 pid_t
 623 getjobpgrp(char *name)
 624 {
 625         struct job *jp;
 626
 627         jp = getjob(name);
 628         return -jp->ps[0].pid;
 629 }
 630
 631 /*
 632  * Return a new job structure,
 633  */
 634
 635 struct job *
 636 makejob(union node *node __unused, int nprocs)
 637 {
 638         int i;
 639         struct job *jp;
 640
 641         for (i = njobs, jp = jobtab ; ; jp++) {
 642                 if (--i < 0) {
 643                         INTOFF;
 644                         if (njobs == 0) {
 645                                 jobtab = ckmalloc(4 * sizeof jobtab[0]);
 646 #if JOBS
 647                                 jobmru = NULL;
 648 #endif
 649                         } else {
 650                                 jp = ckmalloc((njobs + 4) * sizeof jobtab[0]);
 651                                 memcpy(jp, jobtab, njobs * sizeof jp[0]);
 652 #if JOBS
 653                                 /* Relocate `next' pointers and list head */
 654                                 if (jobmru != NULL)
 655                                         jobmru = &jp[jobmru - jobtab];
 656                                 for (i = 0; i < njobs; i++)
 657                                         if (jp[i].next != NULL)
 658                                                 jp[i].next = &jp[jp[i].next -
 659                                                     jobtab];
 660 #endif
 661                                 if (bgjob != NULL)
 662                                         bgjob = &jp[bgjob - jobtab];
 663                                 /* Relocate `ps' pointers */
 664                                 for (i = 0; i < njobs; i++)
 665                                         if (jp[i].ps == &jobtab[i].ps0)
 666                                                 jp[i].ps = &jp[i].ps0;
 667                                 ckfree(jobtab);
 668                                 jobtab = jp;
 669                         }
 670                         jp = jobtab + njobs;
 671                         for (i = 4 ; --i >= 0 ; jobtab[njobs++].used = 0);
 672                         INTON;
 673                         break;
 674                 }
 675                 if (jp->used == 0)
 676                         break;
 677         }
 678         INTOFF;
 679         jp->state = 0;
 680         jp->used = 1;
 681         jp->changed = 0;
 682         jp->nprocs = 0;
 683         jp->foreground = 0;
 684         jp->remembered = 0;
 685 #if JOBS
 686         jp->jobctl = jobctl;
 687         jp->next = NULL;
 688 #endif
 689         if (nprocs > 1) {
 690                 jp->ps = ckmalloc(nprocs * sizeof (struct procstat));
 691         } else {
 692                 jp->ps = &jp->ps0;
 693         }
 694         INTON;
 695         TRACE(("makejob(%p, %d) returns %%%td\n", (void *)node, nprocs,
 696             jp - jobtab + 1));
 697         return jp;
 698 }
 699
 700 #if JOBS
 701 static void
 702 setcurjob(struct job *cj)
 703 {
 704         struct job *jp, *prev;
 705
 706         for (prev = NULL, jp = jobmru; jp != NULL; prev = jp, jp = jp->next) {
 707                 if (jp == cj) {
 708                         if (prev != NULL)
 709                                 prev->next = jp->next;
 710                         else
 711                                 jobmru = jp->next;
 712                         jp->next = jobmru;
 713                         jobmru = cj;
 714                         return;
 715                 }
 716         }
 717         cj->next = jobmru;
 718         jobmru = cj;
 719 }
 720
 721 static void
 722 deljob(struct job *j)
 723 {
 724         struct job *jp, *prev;
 725
 726         for (prev = NULL, jp = jobmru; jp != NULL; prev = jp, jp = jp->next) {
 727                 if (jp == j) {
 728                         if (prev != NULL)
 729                                 prev->next = jp->next;
 730                         else
 731                                 jobmru = jp->next;
 732                         return;
 733                 }
 734         }
 735 }
 736
 737 /*
 738  * Return the most recently used job that isn't `nj', and preferably one
 739  * that is stopped.
 740  */
 741 static struct job *
 742 getcurjob(struct job *nj)
 743 {
 744         struct job *jp;
 745
 746         /* Try to find a stopped one.. */
 747         for (jp = jobmru; jp != NULL; jp = jp->next)
 748                 if (jp->used && jp != nj && jp->state == JOBSTOPPED)
 749                         return (jp);
 750         /* Otherwise the most recently used job that isn't `nj' */
 751         for (jp = jobmru; jp != NULL; jp = jp->next)
 752                 if (jp->used && jp != nj)
 753                         return (jp);
 754
 755         return (NULL);
 756 }
 757
 758 #endif
 759
 760 /*
 761  * Fork of a subshell.  If we are doing job control, give the subshell its
 762  * own process group.  Jp is a job structure that the job is to be added to.
 763  * N is the command that will be evaluated by the child.  Both jp and n may
 764  * be NULL.  The mode parameter can be one of the following:
 765  *      FORK_FG - Fork off a foreground process.
 766  *      FORK_BG - Fork off a background process.
 767  *      FORK_NOJOB - Like FORK_FG, but don't give the process its own
 768  *                   process group even if job control is on.
 769  *
 770  * When job control is turned off, background processes have their standard
 771  * input redirected to /dev/null (except for the second and later processes
 772  * in a pipeline).
 773  */
 774
 775 pid_t
 776 forkshell(struct job *jp, union node *n, int mode)
 777 {
 778         pid_t pid;
 779         pid_t pgrp;
 780
 781         TRACE(("forkshell(%%%td, %p, %d) called\n", jp - jobtab, (void *)n,
 782             mode));
 783         INTOFF;
 784         if (mode == FORK_BG && (jp == NULL || jp->nprocs == 0))
 785                 checkzombies();
 786         flushall();
 787         pid = fork();
 788         if (pid == -1) {
 789                 TRACE(("Fork failed, errno=%d\n", errno));
 790                 INTON;
 791                 error("Cannot fork: %s", strerror(errno));
 792         }
 793         if (pid == 0) {
 794                 struct job *p;
 795                 int wasroot;
 796                 int i;
 797
 798                 TRACE(("Child shell %d\n", (int)getpid()));
 799                 wasroot = rootshell;
 800                 rootshell = 0;
 801                 handler = &main_handler;
 802                 closescript();
 803                 INTON;
 804                 forcelocal = 0;
 805                 clear_traps();
 806 #if JOBS
 807                 jobctl = 0;             /* do job control only in root shell */
 808                 if (wasroot && mode != FORK_NOJOB && mflag) {
 809                         if (jp == NULL || jp->nprocs == 0)
 810                                 pgrp = getpid();
 811                         else
 812                                 pgrp = jp->ps[0].pid;
 813                         if (setpgid(0, pgrp) == 0 && mode == FORK_FG) {
 814                                 /*** this causes superfluous TIOCSPGRPS ***/
 815                                 if (tcsetpgrp(ttyfd, pgrp) < 0)
 816                                         error("tcsetpgrp failed, errno=%d", errno);
 817                         }
 818                         setsignal(SIGTSTP);
 819                         setsignal(SIGTTOU);
 820                 } else if (mode == FORK_BG) {
 821                         ignoresig(SIGINT);
 822                         ignoresig(SIGQUIT);
 823                         if ((jp == NULL || jp->nprocs == 0) &&
 824                             ! fd0_redirected_p ()) {
 825                                 close(0);
 826                                 if (open(_PATH_DEVNULL, O_RDONLY) != 0)
 827                                         error("cannot open %s: %s",
 828                                             _PATH_DEVNULL, strerror(errno));
 829                         }
 830                 }
 831 #else
 832                 if (mode == FORK_BG) {
 833                         ignoresig(SIGINT);
 834                         ignoresig(SIGQUIT);
 835                         if ((jp == NULL || jp->nprocs == 0) &&
 836                             ! fd0_redirected_p ()) {
 837                                 close(0);
 838                                 if (open(_PATH_DEVNULL, O_RDONLY) != 0)
 839                                         error("cannot open %s: %s",
 840                                             _PATH_DEVNULL, strerror(errno));
 841                         }
 842                 }
 843 #endif
 844                 INTOFF;
 845                 for (i = njobs, p = jobtab ; --i >= 0 ; p++)
 846                         if (p->used)
 847                                 freejob(p);
 848                 INTON;
 849                 if (wasroot && iflag) {
 850                         setsignal(SIGINT);
 851                         setsignal(SIGQUIT);
 852                         setsignal(SIGTERM);
 853                 }
 854                 return pid;
 855         }
 856         if (rootshell && mode != FORK_NOJOB && mflag) {
 857                 if (jp == NULL || jp->nprocs == 0)
 858                         pgrp = pid;
 859                 else
 860                         pgrp = jp->ps[0].pid;
 861                 setpgid(pid, pgrp);
 862         }
 863         if (mode == FORK_BG) {
 864                 if (bgjob != NULL && bgjob->state == JOBDONE &&
 865                     !bgjob->remembered && !iflag)
 866                         freejob(bgjob);
 867                 backgndpid = pid;               /* set $! */
 868                 bgjob = jp;
 869         }
 870         if (jp) {
 871                 struct procstat *ps = &jp->ps[jp->nprocs++];
 872                 ps->pid = pid;
 873                 ps->status = -1;
 874                 ps->cmd = nullstr;
 875                 if (iflag && rootshell && n)
 876                         ps->cmd = commandtext(n);
 877                 jp->foreground = mode == FORK_FG;
 878 #if JOBS
 879                 setcurjob(jp);
 880 #endif
 881         }
 882         INTON;
 883         TRACE(("In parent shell:  child = %d\n", (int)pid));
 884         return pid;
 885 }
 886
 887
 888 pid_t
 889 vforkexecshell(struct job *jp, char **argv, char **envp, const char *path, int idx, int pip[2])
 890 {
 891         pid_t pid;
 892         struct jmploc jmploc;
 893         struct jmploc *savehandler;
 894
 895         TRACE(("vforkexecshell(%%%td, %s, %p) called\n", jp - jobtab, argv[0],
 896             (void *)pip));
 897         INTOFF;
 898         flushall();
 899         savehandler = handler;
 900         pid = vfork();
 901         if (pid == -1) {
 902                 TRACE(("Vfork failed, errno=%d\n", errno));
 903                 INTON;
 904                 error("Cannot fork: %s", strerror(errno));
 905         }
 906         if (pid == 0) {
 907                 TRACE(("Child shell %d\n", (int)getpid()));
 908                 if (setjmp(jmploc.loc))
 909                         _exit(exception == EXEXEC ? exerrno : 2);
 910                 if (pip != NULL) {
 911                         close(pip[0]);
 912                         if (pip[1] != 1) {
 913                                 dup2(pip[1], 1);
 914                                 close(pip[1]);
 915                         }
 916                 }
 917                 handler = &jmploc;
 918                 shellexec(argv, envp, path, idx);
 919         }
 920         handler = savehandler;
 921         if (jp) {
 922                 struct procstat *ps = &jp->ps[jp->nprocs++];
 923                 ps->pid = pid;
 924                 ps->status = -1;
 925                 ps->cmd = nullstr;
 926                 jp->foreground = 1;
 927 #if JOBS
 928                 setcurjob(jp);
 929 #endif
 930         }
 931         INTON;
 932         TRACE(("In parent shell:  child = %d\n", (int)pid));
 933         return pid;
 934 }
 935
 936
 937 /*
 938  * Wait for job to finish.
 939  *
 940  * Under job control we have the problem that while a child process is
 941  * running interrupts generated by the user are sent to the child but not
 942  * to the shell.  This means that an infinite loop started by an inter-
 943  * active user may be hard to kill.  With job control turned off, an
 944  * interactive user may place an interactive program inside a loop.  If
 945  * the interactive program catches interrupts, the user doesn't want
 946  * these interrupts to also abort the loop.  The approach we take here
 947  * is to have the shell ignore interrupt signals while waiting for a
 948  * foreground process to terminate, and then send itself an interrupt
 949  * signal if the child process was terminated by an interrupt signal.
 950  * Unfortunately, some programs want to do a bit of cleanup and then
 951  * exit on interrupt; unless these processes terminate themselves by
 952  * sending a signal to themselves (instead of calling exit) they will
 953  * confuse this approach.
 954  */
 955
 956 int
 957 waitforjob(struct job *jp, int *origstatus)
 958 {
 959 #if JOBS
 960         pid_t mypgrp = getpgrp();
 961         int propagate_int = jp->jobctl && jp->foreground;
 962 #endif
 963         int status;
 964         int st;
 965
 966         INTOFF;
 967         TRACE(("waitforjob(%%%td) called\n", jp - jobtab + 1));
 968         while (jp->state == 0)
 969                 if (dowait(1, jp) == -1)
 970                         dotrap();
 971 #if JOBS
 972         if (jp->jobctl) {
 973                 if (tcsetpgrp(ttyfd, mypgrp) < 0)
 974                         error("tcsetpgrp failed, errno=%d\n", errno);
 975         }
 976         if (jp->state == JOBSTOPPED)
 977                 setcurjob(jp);
 978 #endif
 979         status = jp->ps[jp->nprocs - 1].status;
 980         if (origstatus != NULL)
 981                 *origstatus = status;
 982         /* convert to 8 bits */
 983         if (WIFEXITED(status))
 984                 st = WEXITSTATUS(status);
 985 #if JOBS
 986         else if (WIFSTOPPED(status))
 987                 st = WSTOPSIG(status) + 128;
 988 #endif
 989         else
 990                 st = WTERMSIG(status) + 128;
 991         if (! JOBS || jp->state == JOBDONE)
 992                 freejob(jp);
 993         if (int_pending()) {
 994                 if (!WIFSIGNALED(status) || WTERMSIG(status) != SIGINT)
 995                         CLEAR_PENDING_INT;
 996         }
 997 #if JOBS
 998         else if (rootshell && iflag && propagate_int &&
 999                         WIFSIGNALED(status) && WTERMSIG(status) == SIGINT)
1000                 kill(getpid(), SIGINT);
1001 #endif
1002         INTON;
1003         return st;
1004 }
1005
1006
1007
1008 /*
1009  * Wait for a process to terminate.
1010  */
1011
1012 static pid_t
1013 dowait(int block, struct job *job)
1014 {
1015         pid_t pid;
1016         int status;
1017         struct procstat *sp;
1018         struct job *jp;
1019         struct job *thisjob;
1020         int done;
1021         int stopped;
1022         int sig;
1023         int coredump;
1024
1025         in_dowait++;
1026         TRACE(("dowait(%d) called\n", block));
1027         do {
1028                 pid = waitproc(block, &status);
1029                 TRACE(("wait returns %d, status=%d\n", (int)pid, status));
1030         } while ((pid == -1 && errno == EINTR && breakwaitcmd == 0) ||
1031                  (pid > 0 && WIFSTOPPED(status) && !iflag));
1032         in_dowait--;
1033         if (pid == -1 && errno == ECHILD && job != NULL)
1034                 job->state = JOBDONE;
1035         if (breakwaitcmd != 0) {
1036                 breakwaitcmd = 0;
1037                 if (pid <= 0)
1038                         return -1;
1039         }
1040         if (pid <= 0)
1041                 return pid;
1042         INTOFF;
1043         thisjob = NULL;
1044         for (jp = jobtab ; jp < jobtab + njobs ; jp++) {
1045                 if (jp->used && jp->nprocs > 0) {
1046                         done = 1;
1047                         stopped = 1;
1048                         for (sp = jp->ps ; sp < jp->ps + jp->nprocs ; sp++) {
1049                                 if (sp->pid == -1)
1050                                         continue;
1051                                 if (sp->pid == pid) {
1052                                         TRACE(("Changing status of proc %d from 0x%x to 0x%x\n",
1053                                                    (int)pid, sp->status,
1054                                                    status));
1055                                         sp->status = status;
1056                                         thisjob = jp;
1057                                 }
1058                                 if (sp->status == -1)
1059                                         stopped = 0;
1060                                 else if (WIFSTOPPED(sp->status))
1061                                         done = 0;
1062                         }
1063                         if (stopped) {          /* stopped or done */
1064                                 int state = done? JOBDONE : JOBSTOPPED;
1065                                 if (jp->state != state) {
1066                                         TRACE(("Job %td: changing state from %d to %d\n", jp - jobtab + 1, jp->state, state));
1067                                         jp->state = state;
1068                                         if (jp != job) {
1069                                                 if (done && !jp->remembered &&
1070                                                     !iflag && jp != bgjob)
1071                                                         freejob(jp);
1072 #if JOBS
1073                                                 else if (done)
1074                                                         deljob(jp);
1075 #endif
1076                                         }
1077                                 }
1078                         }
1079                 }
1080         }
1081         INTON;
1082         if (!thisjob || thisjob->state == 0)
1083                 ;
1084         else if ((!rootshell || !iflag || thisjob == job) &&
1085             thisjob->foreground && thisjob->state != JOBSTOPPED) {
1086                 sig = 0;
1087                 coredump = 0;
1088                 for (sp = thisjob->ps; sp < thisjob->ps + thisjob->nprocs; sp++)
1089                         if (WIFSIGNALED(sp->status)) {
1090                                 sig = WTERMSIG(sp->status);
1091                                 coredump = WCOREDUMP(sp->status);
1092                         }
1093                 if (sig > 0 && sig != SIGINT && sig != SIGPIPE) {
1094                         if (sig < sys_nsig && sys_siglist[sig])
1095                                 out2str(sys_siglist[sig]);
1096                         else
1097                                 outfmt(out2, "Signal %d", sig);
1098                         if (coredump)
1099                                 out2str(" (core dumped)");
1100                         out2c('\n');
1101                         flushout(out2);
1102                 }
1103         } else {
1104                 TRACE(("Not printing status, rootshell=%d, job=%p\n", rootshell, job));
1105                 thisjob->changed = 1;
1106         }
1107         return pid;
1108 }
1109
1110
1111
1112 /*
1113  * Do a wait system call.  If job control is compiled in, we accept
1114  * stopped processes.  If block is zero, we return a value of zero
1115  * rather than blocking.
1116  */
1117 static pid_t
1118 waitproc(int block, int *status)
1119 {
1120         int flags;
1121
1122 #if JOBS
1123         flags = WUNTRACED;
1124 #else
1125         flags = 0;
1126 #endif
1127         if (block == 0)
1128                 flags |= WNOHANG;
1129         return wait3(status, flags, (struct rusage *)NULL);
1130 }
1131
1132 /*
1133  * return 1 if there are stopped jobs, otherwise 0
1134  */
1135 int job_warning = 0;
1136 int
1137 stoppedjobs(void)
1138 {
1139         int jobno;
1140         struct job *jp;
1141
1142         if (job_warning)
1143                 return (0);
1144         for (jobno = 1, jp = jobtab; jobno <= njobs; jobno++, jp++) {
1145                 if (jp->used == 0)
1146                         continue;
1147                 if (jp->state == JOBSTOPPED) {
1148                         out2fmt_flush("You have stopped jobs.\n");
1149                         job_warning = 2;
1150                         return (1);
1151                 }
1152         }
1153
1154         return (0);
1155 }
1156
1157
1158 static void
1159 checkzombies(void)
1160 {
1161         while (njobs > 0 && dowait(0, NULL) > 0)
1162                 ;
1163 }
1164
1165
1166 int
1167 backgndpidset(void)
1168 {
1169         return backgndpid != -1;
1170 }
1171
1172
1173 pid_t
1174 backgndpidval(void)
1175 {
1176         if (bgjob != NULL && !forcelocal)
1177                 bgjob->remembered = 1;
1178         return backgndpid;
1179 }
1180
1181 /*
1182  * Return a string identifying a command (to be printed by the
1183  * jobs command.
1184  */
1185
1186 static char *cmdnextc;
1187 static int cmdnleft;
1188 #define MAXCMDTEXT      200
1189
1190 char *
1191 commandtext(union node *n)
1192 {
1193         char *name;
1194
1195         cmdnextc = name = ckmalloc(MAXCMDTEXT);
1196         cmdnleft = MAXCMDTEXT - 4;
1197         cmdtxt(n);
1198         *cmdnextc = '\0';
1199         return name;
1200 }
1201
1202
1203 static void
1204 cmdtxt(union node *n)
1205 {
1206         union node *np;
1207         struct nodelist *lp;
1208         const char *p;
1209         int i;
1210         char s[2];
1211
1212         if (n == NULL)
1213                 return;
1214         switch (n->type) {
1215         case NSEMI:
1216                 cmdtxt(n->nbinary.ch1);
1217                 cmdputs("; ");
1218                 cmdtxt(n->nbinary.ch2);
1219                 break;
1220         case NAND:
1221                 cmdtxt(n->nbinary.ch1);
1222                 cmdputs(" && ");
1223                 cmdtxt(n->nbinary.ch2);
1224                 break;
1225         case NOR:
1226                 cmdtxt(n->nbinary.ch1);
1227                 cmdputs(" || ");
1228                 cmdtxt(n->nbinary.ch2);
1229                 break;
1230         case NPIPE:
1231                 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) {
1232                         cmdtxt(lp->n);
1233                         if (lp->next)
1234                                 cmdputs(" | ");
1235                 }
1236                 break;
1237         case NSUBSHELL:
1238                 cmdputs("(");
1239                 cmdtxt(n->nredir.n);
1240                 cmdputs(")");
1241                 break;
1242         case NREDIR:
1243         case NBACKGND:
1244                 cmdtxt(n->nredir.n);
1245                 break;
1246         case NIF:
1247                 cmdputs("if ");
1248                 cmdtxt(n->nif.test);
1249                 cmdputs("; then ");
1250                 cmdtxt(n->nif.ifpart);
1251                 cmdputs("...");
1252                 break;
1253         case NWHILE:
1254                 cmdputs("while ");
1255                 goto until;
1256         case NUNTIL:
1257                 cmdputs("until ");
1258 until:
1259                 cmdtxt(n->nbinary.ch1);
1260                 cmdputs("; do ");
1261                 cmdtxt(n->nbinary.ch2);
1262                 cmdputs("; done");
1263                 break;
1264         case NFOR:
1265                 cmdputs("for ");
1266                 cmdputs(n->nfor.var);
1267                 cmdputs(" in ...");
1268                 break;
1269         case NCASE:
1270                 cmdputs("case ");
1271                 cmdputs(n->ncase.expr->narg.text);
1272                 cmdputs(" in ...");
1273                 break;
1274         case NDEFUN:
1275                 cmdputs(n->narg.text);
1276                 cmdputs("() ...");
1277                 break;
1278         case NCMD:
1279                 for (np = n->ncmd.args ; np ; np = np->narg.next) {
1280                         cmdtxt(np);
1281                         if (np->narg.next)
1282                                 cmdputs(" ");
1283                 }
1284                 for (np = n->ncmd.redirect ; np ; np = np->nfile.next) {
1285                         cmdputs(" ");
1286                         cmdtxt(np);
1287                 }
1288                 break;
1289         case NARG:
1290                 cmdputs(n->narg.text);
1291                 break;
1292         case NTO:
1293                 p = ">";  i = 1;  goto redir;
1294         case NAPPEND:
1295                 p = ">>";  i = 1;  goto redir;
1296         case NTOFD:
1297                 p = ">&";  i = 1;  goto redir;
1298         case NCLOBBER:
1299                 p = ">|"; i = 1; goto redir;
1300         case NFROM:
1301                 p = "<";  i = 0;  goto redir;
1302         case NFROMTO:
1303                 p = "<>";  i = 0;  goto redir;
1304         case NFROMFD:
1305                 p = "<&";  i = 0;  goto redir;
1306 redir:
1307                 if (n->nfile.fd != i) {
1308                         s[0] = n->nfile.fd + '0';
1309                         s[1] = '\0';
1310                         cmdputs(s);
1311                 }
1312                 cmdputs(p);
1313                 if (n->type == NTOFD || n->type == NFROMFD) {
1314                         if (n->ndup.dupfd >= 0)
1315                                 s[0] = n->ndup.dupfd + '0';
1316                         else
1317                                 s[0] = '-';
1318                         s[1] = '\0';
1319                         cmdputs(s);
1320                 } else {
1321                         cmdtxt(n->nfile.fname);
1322                 }
1323                 break;
1324         case NHERE:
1325         case NXHERE:
1326                 cmdputs("<<...");
1327                 break;
1328         default:
1329                 cmdputs("???");
1330                 break;
1331         }
1332 }
1333
1334
1335
1336 static void
1337 cmdputs(const char *s)
1338 {
1339         const char *p;
1340         char *q;
1341         char c;
1342         int subtype = 0;
1343
1344         if (cmdnleft <= 0)
1345                 return;
1346         p = s;
1347         q = cmdnextc;
1348         while ((c = *p++) != '\0') {
1349                 if (c == CTLESC)
1350                         *q++ = *p++;
1351                 else if (c == CTLVAR) {
1352                         *q++ = '$';
1353                         if (--cmdnleft > 0)
1354                                 *q++ = '{';
1355                         subtype = *p++;
1356                         if ((subtype & VSTYPE) == VSLENGTH && --cmdnleft > 0)
1357                                 *q++ = '#';
1358                 } else if (c == '=' && subtype != 0) {
1359                         *q = "}-+?=##%%\0X"[(subtype & VSTYPE) - VSNORMAL];
1360                         if (*q)
1361                                 q++;
1362                         else
1363                                 cmdnleft++;
1364                         if (((subtype & VSTYPE) == VSTRIMLEFTMAX ||
1365                             (subtype & VSTYPE) == VSTRIMRIGHTMAX) &&
1366                             --cmdnleft > 0)
1367                                 *q = q[-1], q++;
1368                         subtype = 0;
1369                 } else if (c == CTLENDVAR) {
1370                         *q++ = '}';
1371                 } else if (c == CTLBACKQ || c == CTLBACKQ+CTLQUOTE) {
1372                         cmdnleft -= 5;
1373                         if (cmdnleft > 0) {
1374                                 *q++ = '$';
1375                                 *q++ = '(';
1376                                 *q++ = '.';
1377                                 *q++ = '.';
1378                                 *q++ = '.';
1379                                 *q++ = ')';
1380                         }
1381                 } else if (c == CTLARI) {
1382                         cmdnleft -= 2;
1383                         if (cmdnleft > 0) {
1384                                 *q++ = '$';
1385                                 *q++ = '(';
1386                                 *q++ = '(';
1387                         }
1388                         p++;
1389                 } else if (c == CTLENDARI) {
1390                         if (--cmdnleft > 0) {
1391                                 *q++ = ')';
1392                                 *q++ = ')';
1393                         }
1394                 } else if (c == CTLQUOTEMARK || c == CTLQUOTEEND)
1395                         cmdnleft++; /* ignore */
1396                 else
1397                         *q++ = c;
1398                 if (--cmdnleft <= 0) {
1399                         *q++ = '.';
1400                         *q++ = '.';
1401                         *q++ = '.';
1402                         break;
1403                 }
1404         }
1405         cmdnextc = q;
1406 }