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  * 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  * @(#)jobs.c   8.5 (Berkeley) 5/4/95
  37  * $FreeBSD: src/bin/sh/jobs.c,v 1.94 2011/06/12 23:06:04 jilles Exp $
  38  */
  39
  40 #include <sys/ioctl.h>
  41 #include <sys/param.h>
  42 #include <sys/resource.h>
  43 #include <sys/time.h>
  44 #include <sys/wait.h>
  45 #include <errno.h>
  46 #include <fcntl.h>
  47 #include <paths.h>
  48 #include <signal.h>
  49 #include <stddef.h>
  50 #include <stdlib.h>
  51 #include <unistd.h>
  52
  53 #include "shell.h"
  54 #if JOBS
  55 #include <termios.h>
  56 #undef CEOF                     /* syntax.h redefines this */
  57 #endif
  58 #include "redir.h"
  59 #include "show.h"
  60 #include "main.h"
  61 #include "parser.h"
  62 #include "nodes.h"
  63 #include "jobs.h"
  64 #include "options.h"
  65 #include "trap.h"
  66 #include "syntax.h"
  67 #include "input.h"
  68 #include "output.h"
  69 #include "memalloc.h"
  70 #include "error.h"
  71 #include "mystring.h"
  72 #include "var.h"
  73
  74
  75 static struct job *jobtab;      /* array of jobs */
  76 static int njobs;               /* size of array */
  77 MKINIT pid_t backgndpid = -1;   /* pid of last background process */
  78 MKINIT struct job *bgjob = NULL; /* last background process */
  79 #if JOBS
  80 static struct job *jobmru;      /* most recently used job list */
  81 static pid_t initialpgrp;       /* pgrp of shell on invocation */
  82 #endif
  83 int in_waitcmd = 0;             /* are we in waitcmd()? */
  84 int in_dowait = 0;              /* are we in dowait()? */
  85 volatile sig_atomic_t breakwaitcmd = 0; /* should wait be terminated? */
  86 static int ttyfd = -1;
  87
  88 #if JOBS
  89 static void restartjob(struct job *);
  90 #endif
  91 static void freejob(struct job *);
  92 static struct job *getjob(char *);
  93 static pid_t dowait(int, struct job *);
  94 static pid_t waitproc(int, int *);
  95 static void checkzombies(void);
  96 static void cmdtxt(union node *);
  97 static void cmdputs(const char *);
  98 #if JOBS
  99 static void setcurjob(struct job *);
 100 static void deljob(struct job *);
 101 static struct job *getcurjob(struct job *);
 102 #endif
 103 static void printjobcmd(struct job *);
 104 static void showjob(struct job *, int);
 105
 106
 107 /*
 108  * Turn job control on and off.
 109  */
 110
 111 MKINIT int jobctl;
 112
 113 #if JOBS
 114 void
 115 setjobctl(int on)
 116 {
 117         int i;
 118
 119         if (on == jobctl || rootshell == 0)
 120                 return;
 121         if (on) {
 122                 if (ttyfd != -1)
 123                         close(ttyfd);
 124                 if ((ttyfd = open(_PATH_TTY, O_RDWR)) < 0) {
 125                         i = 0;
 126                         while (i <= 2 && !isatty(i))
 127                                 i++;
 128                         if (i > 2 || (ttyfd = fcntl(i, F_DUPFD, 10)) < 0)
 129                                 goto out;
 130                 }
 131                 if (ttyfd < 10) {
 132                         /*
 133                          * Keep our TTY file descriptor out of the way of
 134                          * the user's redirections.
 135                          */
 136                         if ((i = fcntl(ttyfd, F_DUPFD, 10)) < 0) {
 137                                 close(ttyfd);
 138                                 ttyfd = -1;
 139                                 goto out;
 140                         }
 141                         close(ttyfd);
 142                         ttyfd = i;
 143                 }
 144                 if (fcntl(ttyfd, F_SETFD, FD_CLOEXEC) < 0) {
 145                         close(ttyfd);
 146                         ttyfd = -1;
 147                         goto out;
 148                 }
 149                 do { /* while we are in the background */
 150                         initialpgrp = tcgetpgrp(ttyfd);
 151                         if (initialpgrp < 0) {
 152 out:                            out2fmt_flush("sh: can't access tty; job control turned off\n");
 153                                 mflag = 0;
 154                                 return;
 155                         }
 156                         if (initialpgrp != getpgrp()) {
 157                                 kill(0, SIGTTIN);
 158                                 continue;
 159                         }
 160                 } while (0);
 161                 setsignal(SIGTSTP);
 162                 setsignal(SIGTTOU);
 163                 setsignal(SIGTTIN);
 164                 setpgid(0, rootpid);
 165                 tcsetpgrp(ttyfd, rootpid);
 166         } else { /* turning job control off */
 167                 setpgid(0, initialpgrp);
 168                 tcsetpgrp(ttyfd, initialpgrp);
 169                 close(ttyfd);
 170                 ttyfd = -1;
 171                 setsignal(SIGTSTP);
 172                 setsignal(SIGTTOU);
 173                 setsignal(SIGTTIN);
 174         }
 175         jobctl = on;
 176 }
 177 #endif
 178
 179
 180 #if JOBS
 181 int
 182 fgcmd(int argc __unused, char **argv)
 183 {
 184         struct job *jp;
 185         pid_t pgrp;
 186         int status;
 187
 188         jp = getjob(argv[1]);
 189         if (jp->jobctl == 0)
 190                 error("job not created under job control");
 191         printjobcmd(jp);
 192         flushout(&output);
 193         pgrp = jp->ps[0].pid;
 194         tcsetpgrp(ttyfd, pgrp);
 195         restartjob(jp);
 196         jp->foreground = 1;
 197         INTOFF;
 198         status = waitforjob(jp, NULL);
 199         INTON;
 200         return status;
 201 }
 202
 203
 204 int
 205 bgcmd(int argc, char **argv)
 206 {
 207         struct job *jp;
 208
 209         do {
 210                 jp = getjob(*++argv);
 211                 if (jp->jobctl == 0)
 212                         error("job not created under job control");
 213                 if (jp->state == JOBDONE)
 214                         continue;
 215                 restartjob(jp);
 216                 jp->foreground = 0;
 217                 out1fmt("[%td] ", jp - jobtab + 1);
 218                 printjobcmd(jp);
 219         } while (--argc > 1);
 220         return 0;
 221 }
 222
 223
 224 static void
 225 restartjob(struct job *jp)
 226 {
 227         struct procstat *ps;
 228         int i;
 229
 230         if (jp->state == JOBDONE)
 231                 return;
 232         setcurjob(jp);
 233         INTOFF;
 234         kill(-jp->ps[0].pid, SIGCONT);
 235         for (ps = jp->ps, i = jp->nprocs ; --i >= 0 ; ps++) {
 236                 if (WIFSTOPPED(ps->status)) {
 237                         ps->status = -1;
 238                         jp->state = 0;
 239                 }
 240         }
 241         INTON;
 242 }
 243 #endif
 244
 245
 246 int
 247 jobscmd(int argc, char *argv[])
 248 {
 249         char *id;
 250         int ch, mode;
 251
 252         optind = optreset = 1;
 253         opterr = 0;
 254         mode = SHOWJOBS_DEFAULT;
 255         while ((ch = getopt(argc, argv, "lps")) != -1) {
 256                 switch (ch) {
 257                 case 'l':
 258                         mode = SHOWJOBS_VERBOSE;
 259                         break;
 260                 case 'p':
 261                         mode = SHOWJOBS_PGIDS;
 262                         break;
 263                 case 's':
 264                         mode = SHOWJOBS_PIDS;
 265                         break;
 266                 case '?':
 267                 default:
 268                         error("unknown option: -%c", optopt);
 269                 }
 270         }
 271         argc -= optind;
 272         argv += optind;
 273
 274         if (argc == 0)
 275                 showjobs(0, mode);
 276         else
 277                 while ((id = *argv++) != NULL)
 278                         showjob(getjob(id), mode);
 279
 280         return (0);
 281 }
 282
 283 static void
 284 printjobcmd(struct job *jp)
 285 {
 286         struct procstat *ps;
 287         int i;
 288
 289         for (ps = jp->ps, i = jp->nprocs ; --i >= 0 ; ps++) {
 290                 out1str(ps->cmd);
 291                 if (i > 0)
 292                         out1str(" | ");
 293         }
 294         out1c('\n');
 295 }
 296
 297 static void
 298 showjob(struct job *jp, int mode)
 299 {
 300         char s[64];
 301         char statestr[64];
 302         struct procstat *ps;
 303         struct job *j;
 304         int col, curr, i, jobno, prev, procno;
 305         char c;
 306
 307         procno = (mode == SHOWJOBS_PGIDS) ? 1 : jp->nprocs;
 308         jobno = jp - jobtab + 1;
 309         curr = prev = 0;
 310 #if JOBS
 311         if ((j = getcurjob(NULL)) != NULL) {
 312                 curr = j - jobtab + 1;
 313                 if ((j = getcurjob(j)) != NULL)
 314                         prev = j - jobtab + 1;
 315         }
 316 #endif
 317         ps = jp->ps + jp->nprocs - 1;
 318         if (jp->state == 0) {
 319                 strcpy(statestr, "Running");
 320 #if JOBS
 321         } else if (jp->state == JOBSTOPPED) {
 322                 while (!WIFSTOPPED(ps->status) && ps > jp->ps)
 323                         ps--;
 324                 if (WIFSTOPPED(ps->status))
 325                         i = WSTOPSIG(ps->status);
 326                 else
 327                         i = -1;
 328                 if (i > 0 && i < sys_nsig && sys_siglist[i])
 329                         strcpy(statestr, sys_siglist[i]);
 330                 else
 331                         strcpy(statestr, "Suspended");
 332 #endif
 333         } else if (WIFEXITED(ps->status)) {
 334                 if (WEXITSTATUS(ps->status) == 0)
 335                         strcpy(statestr, "Done");
 336                 else
 337                         fmtstr(statestr, 64, "Done(%d)",
 338                             WEXITSTATUS(ps->status));
 339         } else {
 340                 i = WTERMSIG(ps->status);
 341                 if (i > 0 && i < sys_nsig && sys_siglist[i])
 342                         strcpy(statestr, sys_siglist[i]);
 343                 else
 344                         fmtstr(statestr, 64, "Signal %d", i);
 345                 if (WCOREDUMP(ps->status))
 346                         strcat(statestr, " (core dumped)");
 347         }
 348
 349         for (ps = jp->ps ; ; ps++) {    /* for each process */
 350                 if (mode == SHOWJOBS_PIDS || mode == SHOWJOBS_PGIDS) {
 351                         out1fmt("%d\n", (int)ps->pid);
 352                         goto skip;
 353                 }
 354                 if (mode != SHOWJOBS_VERBOSE && ps != jp->ps)
 355                         goto skip;
 356                 if (jobno == curr && ps == jp->ps)
 357                         c = '+';
 358                 else if (jobno == prev && ps == jp->ps)
 359                         c = '-';
 360                 else
 361                         c = ' ';
 362                 if (ps == jp->ps)
 363                         fmtstr(s, 64, "[%d] %c ", jobno, c);
 364                 else
 365                         fmtstr(s, 64, "    %c ", c);
 366                 out1str(s);
 367                 col = strlen(s);
 368                 if (mode == SHOWJOBS_VERBOSE) {
 369                         fmtstr(s, 64, "%d ", (int)ps->pid);
 370                         out1str(s);
 371                         col += strlen(s);
 372                 }
 373                 if (ps == jp->ps) {
 374                         out1str(statestr);
 375                         col += strlen(statestr);
 376                 }
 377                 do {
 378                         out1c(' ');
 379                         col++;
 380                 } while (col < 30);
 381                 if (mode == SHOWJOBS_VERBOSE) {
 382                         out1str(ps->cmd);
 383                         out1c('\n');
 384                 } else
 385                         printjobcmd(jp);
 386 skip:           if (--procno <= 0)
 387                         break;
 388         }
 389 }
 390
 391 /*
 392  * Print a list of jobs.  If "change" is nonzero, only print jobs whose
 393  * statuses have changed since the last call to showjobs.
 394  *
 395  * If the shell is interrupted in the process of creating a job, the
 396  * result may be a job structure containing zero processes.  Such structures
 397  * will be freed here.
 398  */
 399
 400 void
 401 showjobs(int change, int mode)
 402 {
 403         int jobno;
 404         struct job *jp;
 405
 406         TRACE(("showjobs(%d) called\n", change));
 407         checkzombies();
 408         for (jobno = 1, jp = jobtab ; jobno <= njobs ; jobno++, jp++) {
 409                 if (! jp->used)
 410                         continue;
 411                 if (jp->nprocs == 0) {
 412                         freejob(jp);
 413                         continue;
 414                 }
 415                 if (change && ! jp->changed)
 416                         continue;
 417                 showjob(jp, mode);
 418                 jp->changed = 0;
 419                 /* Hack: discard jobs for which $! has not been referenced
 420                  * in interactive mode when they terminate.
 421                  */
 422                 if (jp->state == JOBDONE && !jp->remembered &&
 423                                 (iflag || jp != bgjob)) {
 424                         freejob(jp);
 425                 }
 426         }
 427 }
 428
 429
 430 /*
 431  * Mark a job structure as unused.
 432  */
 433
 434 static void
 435 freejob(struct job *jp)
 436 {
 437         struct procstat *ps;
 438         int i;
 439
 440         INTOFF;
 441         if (bgjob == jp)
 442                 bgjob = NULL;
 443         for (i = jp->nprocs, ps = jp->ps ; --i >= 0 ; ps++) {
 444                 if (ps->cmd != nullstr)
 445                         ckfree(ps->cmd);
 446         }
 447         if (jp->ps != &jp->ps0)
 448                 ckfree(jp->ps);
 449         jp->used = 0;
 450 #if JOBS
 451         deljob(jp);
 452 #endif
 453         INTON;
 454 }
 455
 456
 457
 458 int
 459 waitcmd(int argc, char **argv)
 460 {
 461         struct job *job;
 462         int status, retval;
 463         struct job *jp;
 464
 465         if (argc > 1) {
 466                 job = getjob(argv[1]);
 467         } else {
 468                 job = NULL;
 469         }
 470
 471         /*
 472          * Loop until a process is terminated or stopped, or a SIGINT is
 473          * received.
 474          */
 475
 476         in_waitcmd++;
 477         do {
 478                 if (job != NULL) {
 479                         if (job->state) {
 480                                 status = job->ps[job->nprocs - 1].status;
 481                                 if (WIFEXITED(status))
 482                                         retval = WEXITSTATUS(status);
 483 #if JOBS
 484                                 else if (WIFSTOPPED(status))
 485                                         retval = WSTOPSIG(status) + 128;
 486 #endif
 487                                 else
 488                                         retval = WTERMSIG(status) + 128;
 489                                 if (! iflag || ! job->changed)
 490                                         freejob(job);
 491                                 else {
 492                                         job->remembered = 0;
 493                                         if (job == bgjob)
 494                                                 bgjob = NULL;
 495                                 }
 496                                 in_waitcmd--;
 497                                 return retval;
 498                         }
 499                 } else {
 500                         for (jp = jobtab ; jp < jobtab + njobs; jp++)
 501                                 if (jp->used && jp->state == JOBDONE) {
 502                                         if (! iflag || ! jp->changed)
 503                                                 freejob(jp);
 504                                         else {
 505                                                 jp->remembered = 0;
 506                                                 if (jp == bgjob)
 507                                                         bgjob = NULL;
 508                                         }
 509                                 }
 510                         for (jp = jobtab ; ; jp++) {
 511                                 if (jp >= jobtab + njobs) {     /* no running procs */
 512                                         in_waitcmd--;
 513                                         return 0;
 514                                 }
 515                                 if (jp->used && jp->state == 0)
 516                                         break;
 517                         }
 518                 }
 519         } while (dowait(1, NULL) != -1);
 520         in_waitcmd--;
 521
 522         return 0;
 523 }
 524
 525
 526
 527 int
 528 jobidcmd(int argc __unused, char **argv)
 529 {
 530         struct job *jp;
 531         int i;
 532
 533         jp = getjob(argv[1]);
 534         for (i = 0 ; i < jp->nprocs ; ) {
 535                 out1fmt("%d", (int)jp->ps[i].pid);
 536                 out1c(++i < jp->nprocs? ' ' : '\n');
 537         }
 538         return 0;
 539 }
 540
 541
 542
 543 /*
 544  * Convert a job name to a job structure.
 545  */
 546
 547 static struct job *
 548 getjob(char *name)
 549 {
 550         int jobno;
 551         struct job *found, *jp;
 552         pid_t pid;
 553         int i;
 554
 555         if (name == NULL) {
 556 #if JOBS
 557 currentjob:     if ((jp = getcurjob(NULL)) == NULL)
 558                         error("No current job");
 559                 return (jp);
 560 #else
 561                 error("No current job");
 562 #endif
 563         } else if (name[0] == '%') {
 564                 if (is_digit(name[1])) {
 565                         jobno = number(name + 1);
 566                         if (jobno > 0 && jobno <= njobs
 567                          && jobtab[jobno - 1].used != 0)
 568                                 return &jobtab[jobno - 1];
 569 #if JOBS
 570                 } else if (name[1] == '%' && name[2] == '\0') {
 571                         goto currentjob;
 572                 } else if (name[1] == '+' && name[2] == '\0') {
 573                         goto currentjob;
 574                 } else if (name[1] == '-' && name[2] == '\0') {
 575                         if ((jp = getcurjob(NULL)) == NULL ||
 576                             (jp = getcurjob(jp)) == NULL)
 577                                 error("No previous job");
 578                         return (jp);
 579 #endif
 580                 } else if (name[1] == '?') {
 581                         found = NULL;
 582                         for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
 583                                 if (jp->used && jp->nprocs > 0
 584                                  && strstr(jp->ps[0].cmd, name + 2) != NULL) {
 585                                         if (found)
 586                                                 error("%s: ambiguous", name);
 587                                         found = jp;
 588                                 }
 589                         }
 590                         if (found != NULL)
 591                                 return (found);
 592                 } else {
 593                         found = NULL;
 594                         for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
 595                                 if (jp->used && jp->nprocs > 0
 596                                  && prefix(name + 1, jp->ps[0].cmd)) {
 597                                         if (found)
 598                                                 error("%s: ambiguous", name);
 599                                         found = jp;
 600                                 }
 601                         }
 602                         if (found)
 603                                 return found;
 604                 }
 605         } else if (is_number(name)) {
 606                 pid = (pid_t)number(name);
 607                 for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
 608                         if (jp->used && jp->nprocs > 0
 609                          && jp->ps[jp->nprocs - 1].pid == pid)
 610                                 return jp;
 611                 }
 612         }
 613         error("No such job: %s", name);
 614         /*NOTREACHED*/
 615         return NULL;
 616 }
 617
 618
 619 pid_t
 620 getjobpgrp(char *name)
 621 {
 622         struct job *jp;
 623
 624         jp = getjob(name);
 625         return -jp->ps[0].pid;
 626 }
 627
 628 /*
 629  * Return a new job structure,
 630  */
 631
 632 struct job *
 633 makejob(union node *node __unused, int nprocs)
 634 {
 635         int i;
 636         struct job *jp;
 637
 638         for (i = njobs, jp = jobtab ; ; jp++) {
 639                 if (--i < 0) {
 640                         INTOFF;
 641                         if (njobs == 0) {
 642                                 jobtab = ckmalloc(4 * sizeof jobtab[0]);
 643 #if JOBS
 644                                 jobmru = NULL;
 645 #endif
 646                         } else {
 647                                 jp = ckmalloc((njobs + 4) * sizeof jobtab[0]);
 648                                 memcpy(jp, jobtab, njobs * sizeof jp[0]);
 649 #if JOBS
 650                                 /* Relocate `next' pointers and list head */
 651                                 if (jobmru != NULL)
 652                                         jobmru = &jp[jobmru - jobtab];
 653                                 for (i = 0; i < njobs; i++)
 654                                         if (jp[i].next != NULL)
 655                                                 jp[i].next = &jp[jp[i].next -
 656                                                     jobtab];
 657 #endif
 658                                 if (bgjob != NULL)
 659                                         bgjob = &jp[bgjob - jobtab];
 660                                 /* Relocate `ps' pointers */
 661                                 for (i = 0; i < njobs; i++)
 662                                         if (jp[i].ps == &jobtab[i].ps0)
 663                                                 jp[i].ps = &jp[i].ps0;
 664                                 ckfree(jobtab);
 665                                 jobtab = jp;
 666                         }
 667                         jp = jobtab + njobs;
 668                         for (i = 4 ; --i >= 0 ; jobtab[njobs++].used = 0);
 669                         INTON;
 670                         break;
 671                 }
 672                 if (jp->used == 0)
 673                         break;
 674         }
 675         INTOFF;
 676         jp->state = 0;
 677         jp->used = 1;
 678         jp->changed = 0;
 679         jp->nprocs = 0;
 680         jp->foreground = 0;
 681         jp->remembered = 0;
 682 #if JOBS
 683         jp->jobctl = jobctl;
 684         jp->next = NULL;
 685 #endif
 686         if (nprocs > 1) {
 687                 jp->ps = ckmalloc(nprocs * sizeof (struct procstat));
 688         } else {
 689                 jp->ps = &jp->ps0;
 690         }
 691         INTON;
 692         TRACE(("makejob(%p, %d) returns %%%td\n", (void *)node, nprocs,
 693             jp - jobtab + 1));
 694         return jp;
 695 }
 696
 697 #if JOBS
 698 static void
 699 setcurjob(struct job *cj)
 700 {
 701         struct job *jp, *prev;
 702
 703         for (prev = NULL, jp = jobmru; jp != NULL; prev = jp, jp = jp->next) {
 704                 if (jp == cj) {
 705                         if (prev != NULL)
 706                                 prev->next = jp->next;
 707                         else
 708                                 jobmru = jp->next;
 709                         jp->next = jobmru;
 710                         jobmru = cj;
 711                         return;
 712                 }
 713         }
 714         cj->next = jobmru;
 715         jobmru = cj;
 716 }
 717
 718 static void
 719 deljob(struct job *j)
 720 {
 721         struct job *jp, *prev;
 722
 723         for (prev = NULL, jp = jobmru; jp != NULL; prev = jp, jp = jp->next) {
 724                 if (jp == j) {
 725                         if (prev != NULL)
 726                                 prev->next = jp->next;
 727                         else
 728                                 jobmru = jp->next;
 729                         return;
 730                 }
 731         }
 732 }
 733
 734 /*
 735  * Return the most recently used job that isn't `nj', and preferably one
 736  * that is stopped.
 737  */
 738 static struct job *
 739 getcurjob(struct job *nj)
 740 {
 741         struct job *jp;
 742
 743         /* Try to find a stopped one.. */
 744         for (jp = jobmru; jp != NULL; jp = jp->next)
 745                 if (jp->used && jp != nj && jp->state == JOBSTOPPED)
 746                         return (jp);
 747         /* Otherwise the most recently used job that isn't `nj' */
 748         for (jp = jobmru; jp != NULL; jp = jp->next)
 749                 if (jp->used && jp != nj)
 750                         return (jp);
 751
 752         return (NULL);
 753 }
 754
 755 #endif
 756
 757 /*
 758  * Fork of a subshell.  If we are doing job control, give the subshell its
 759  * own process group.  Jp is a job structure that the job is to be added to.
 760  * N is the command that will be evaluated by the child.  Both jp and n may
 761  * be NULL.  The mode parameter can be one of the following:
 762  *      FORK_FG - Fork off a foreground process.
 763  *      FORK_BG - Fork off a background process.
 764  *      FORK_NOJOB - Like FORK_FG, but don't give the process its own
 765  *                   process group even if job control is on.
 766  *
 767  * When job control is turned off, background processes have their standard
 768  * input redirected to /dev/null (except for the second and later processes
 769  * in a pipeline).
 770  */
 771
 772 pid_t
 773 forkshell(struct job *jp, union node *n, int mode)
 774 {
 775         pid_t pid;
 776         pid_t pgrp;
 777
 778         TRACE(("forkshell(%%%td, %p, %d) called\n", jp - jobtab, (void *)n,
 779             mode));
 780         INTOFF;
 781         if (mode == FORK_BG && (jp == NULL || jp->nprocs == 0))
 782                 checkzombies();
 783         flushall();
 784         pid = fork();
 785         if (pid == -1) {
 786                 TRACE(("Fork failed, errno=%d\n", errno));
 787                 INTON;
 788                 error("Cannot fork: %s", strerror(errno));
 789         }
 790         if (pid == 0) {
 791                 struct job *p;
 792                 int wasroot;
 793                 int i;
 794
 795                 TRACE(("Child shell %d\n", (int)getpid()));
 796                 wasroot = rootshell;
 797                 rootshell = 0;
 798                 handler = &main_handler;
 799                 closescript();
 800                 INTON;
 801                 forcelocal = 0;
 802                 clear_traps();
 803 #if JOBS
 804                 jobctl = 0;             /* do job control only in root shell */
 805                 if (wasroot && mode != FORK_NOJOB && mflag) {
 806                         if (jp == NULL || jp->nprocs == 0)
 807                                 pgrp = getpid();
 808                         else
 809                                 pgrp = jp->ps[0].pid;
 810                         if (setpgid(0, pgrp) == 0 && mode == FORK_FG) {
 811                                 /*** this causes superfluous TIOCSPGRPS ***/
 812                                 if (tcsetpgrp(ttyfd, pgrp) < 0)
 813                                         error("tcsetpgrp failed, errno=%d", errno);
 814                         }
 815                         setsignal(SIGTSTP);
 816                         setsignal(SIGTTOU);
 817                 } else if (mode == FORK_BG) {
 818                         ignoresig(SIGINT);
 819                         ignoresig(SIGQUIT);
 820                         if ((jp == NULL || jp->nprocs == 0) &&
 821                             ! fd0_redirected_p ()) {
 822                                 close(0);
 823                                 if (open(_PATH_DEVNULL, O_RDONLY) != 0)
 824                                         error("cannot open %s: %s",
 825                                             _PATH_DEVNULL, strerror(errno));
 826                         }
 827                 }
 828 #else
 829                 if (mode == FORK_BG) {
 830                         ignoresig(SIGINT);
 831                         ignoresig(SIGQUIT);
 832                         if ((jp == NULL || jp->nprocs == 0) &&
 833                             ! fd0_redirected_p ()) {
 834                                 close(0);
 835                                 if (open(_PATH_DEVNULL, O_RDONLY) != 0)
 836                                         error("cannot open %s: %s",
 837                                             _PATH_DEVNULL, strerror(errno));
 838                         }
 839                 }
 840 #endif
 841                 INTOFF;
 842                 for (i = njobs, p = jobtab ; --i >= 0 ; p++)
 843                         if (p->used)
 844                                 freejob(p);
 845                 INTON;
 846                 if (wasroot && iflag) {
 847                         setsignal(SIGINT);
 848                         setsignal(SIGQUIT);
 849                         setsignal(SIGTERM);
 850                 }
 851                 return pid;
 852         }
 853         if (rootshell && mode != FORK_NOJOB && mflag) {
 854                 if (jp == NULL || jp->nprocs == 0)
 855                         pgrp = pid;
 856                 else
 857                         pgrp = jp->ps[0].pid;
 858                 setpgid(pid, pgrp);
 859         }
 860         if (mode == FORK_BG) {
 861                 if (bgjob != NULL && bgjob->state == JOBDONE &&
 862                     !bgjob->remembered && !iflag)
 863                         freejob(bgjob);
 864                 backgndpid = pid;               /* set $! */
 865                 bgjob = jp;
 866         }
 867         if (jp) {
 868                 struct procstat *ps = &jp->ps[jp->nprocs++];
 869                 ps->pid = pid;
 870                 ps->status = -1;
 871                 ps->cmd = nullstr;
 872                 if (iflag && rootshell && n)
 873                         ps->cmd = commandtext(n);
 874                 jp->foreground = mode == FORK_FG;
 875 #if JOBS
 876                 setcurjob(jp);
 877 #endif
 878         }
 879         INTON;
 880         TRACE(("In parent shell:  child = %d\n", (int)pid));
 881         return pid;
 882 }
 883
 884
 885
 886 /*
 887  * Wait for job to finish.
 888  *
 889  * Under job control we have the problem that while a child process is
 890  * running interrupts generated by the user are sent to the child but not
 891  * to the shell.  This means that an infinite loop started by an inter-
 892  * active user may be hard to kill.  With job control turned off, an
 893  * interactive user may place an interactive program inside a loop.  If
 894  * the interactive program catches interrupts, the user doesn't want
 895  * these interrupts to also abort the loop.  The approach we take here
 896  * is to have the shell ignore interrupt signals while waiting for a
 897  * foreground process to terminate, and then send itself an interrupt
 898  * signal if the child process was terminated by an interrupt signal.
 899  * Unfortunately, some programs want to do a bit of cleanup and then
 900  * exit on interrupt; unless these processes terminate themselves by
 901  * sending a signal to themselves (instead of calling exit) they will
 902  * confuse this approach.
 903  */
 904
 905 int
 906 waitforjob(struct job *jp, int *origstatus)
 907 {
 908 #if JOBS
 909         pid_t mypgrp = getpgrp();
 910         int propagate_int = jp->jobctl && jp->foreground;
 911 #endif
 912         int status;
 913         int st;
 914
 915         INTOFF;
 916         TRACE(("waitforjob(%%%td) called\n", jp - jobtab + 1));
 917         while (jp->state == 0)
 918                 if (dowait(1, jp) == -1)
 919                         dotrap();
 920 #if JOBS
 921         if (jp->jobctl) {
 922                 if (tcsetpgrp(ttyfd, mypgrp) < 0)
 923                         error("tcsetpgrp failed, errno=%d\n", errno);
 924         }
 925         if (jp->state == JOBSTOPPED)
 926                 setcurjob(jp);
 927 #endif
 928         status = jp->ps[jp->nprocs - 1].status;
 929         if (origstatus != NULL)
 930                 *origstatus = status;
 931         /* convert to 8 bits */
 932         if (WIFEXITED(status))
 933                 st = WEXITSTATUS(status);
 934 #if JOBS
 935         else if (WIFSTOPPED(status))
 936                 st = WSTOPSIG(status) + 128;
 937 #endif
 938         else
 939                 st = WTERMSIG(status) + 128;
 940         if (! JOBS || jp->state == JOBDONE)
 941                 freejob(jp);
 942         if (int_pending()) {
 943                 if (!WIFSIGNALED(status) || WTERMSIG(status) != SIGINT)
 944                         CLEAR_PENDING_INT;
 945         }
 946 #if JOBS
 947         else if (rootshell && iflag && propagate_int &&
 948                         WIFSIGNALED(status) && WTERMSIG(status) == SIGINT)
 949                 kill(getpid(), SIGINT);
 950 #endif
 951         INTON;
 952         return st;
 953 }
 954
 955
 956
 957 /*
 958  * Wait for a process to terminate.
 959  */
 960
 961 static pid_t
 962 dowait(int block, struct job *job)
 963 {
 964         pid_t pid;
 965         int status;
 966         struct procstat *sp;
 967         struct job *jp;
 968         struct job *thisjob;
 969         int done;
 970         int stopped;
 971         int sig;
 972         int coredump;
 973
 974         in_dowait++;
 975         TRACE(("dowait(%d) called\n", block));
 976         do {
 977                 pid = waitproc(block, &status);
 978                 TRACE(("wait returns %d, status=%d\n", (int)pid, status));
 979         } while ((pid == -1 && errno == EINTR && breakwaitcmd == 0) ||
 980                  (pid > 0 && WIFSTOPPED(status) && !iflag));
 981         in_dowait--;
 982         if (pid == -1 && errno == ECHILD && job != NULL)
 983                 job->state = JOBDONE;
 984         if (breakwaitcmd != 0) {
 985                 breakwaitcmd = 0;
 986                 /*
 987                  * Do not early terminate if the pid is positive, else the
 988                  * job will not be properly recorded.
 989                  */
 990                 if (pid <= 0)
 991                         return -1;
 992         }
 993         if (pid <= 0)
 994                 return pid;
 995         INTOFF;
 996         thisjob = NULL;
 997         for (jp = jobtab ; jp < jobtab + njobs ; jp++) {
 998                 if (jp->used && jp->nprocs > 0) {
 999                         done = 1;
1000                         stopped = 1;
1001                         for (sp = jp->ps ; sp < jp->ps + jp->nprocs ; sp++) {
1002                                 if (sp->pid == -1)
1003                                         continue;
1004                                 if (sp->pid == pid) {
1005                                         TRACE(("Changing status of proc %d from 0x%x to 0x%x\n",
1006                                                    (int)pid, sp->status,
1007                                                    status));
1008                                         sp->status = status;
1009                                         thisjob = jp;
1010                                 }
1011                                 if (sp->status == -1)
1012                                         stopped = 0;
1013                                 else if (WIFSTOPPED(sp->status))
1014                                         done = 0;
1015                         }
1016                         if (stopped) {          /* stopped or done */
1017                                 int state = done? JOBDONE : JOBSTOPPED;
1018                                 if (jp->state != state) {
1019                                         TRACE(("Job %td: changing state from %d to %d\n", jp - jobtab + 1, jp->state, state));
1020                                         jp->state = state;
1021                                         if (jp != job) {
1022                                                 if (done && !jp->remembered &&
1023                                                     !iflag && jp != bgjob)
1024                                                         freejob(jp);
1025 #if JOBS
1026                                                 else if (done)
1027                                                         deljob(jp);
1028 #endif
1029                                         }
1030                                 }
1031                         }
1032                 }
1033         }
1034         INTON;
1035         if (!thisjob || thisjob->state == 0)
1036                 ;
1037         else if ((!rootshell || !iflag || thisjob == job) &&
1038             thisjob->foreground && thisjob->state != JOBSTOPPED) {
1039                 sig = 0;
1040                 coredump = 0;
1041                 for (sp = thisjob->ps; sp < thisjob->ps + thisjob->nprocs; sp++)
1042                         if (WIFSIGNALED(sp->status)) {
1043                                 sig = WTERMSIG(sp->status);
1044                                 coredump = WCOREDUMP(sp->status);
1045                         }
1046                 if (sig > 0 && sig != SIGINT && sig != SIGPIPE) {
1047                         if (sig < sys_nsig && sys_siglist[sig])
1048                                 out2str(sys_siglist[sig]);
1049                         else
1050                                 outfmt(out2, "Signal %d", sig);
1051                         if (coredump)
1052                                 out2str(" (core dumped)");
1053                         out2c('\n');
1054                         flushout(out2);
1055                 }
1056         } else {
1057                 TRACE(("Not printing status, rootshell=%d, job=%p\n", rootshell, job));
1058                 thisjob->changed = 1;
1059         }
1060         return pid;
1061 }
1062
1063
1064
1065 /*
1066  * Do a wait system call.  If job control is compiled in, we accept
1067  * stopped processes.  If block is zero, we return a value of zero
1068  * rather than blocking.
1069  */
1070 static pid_t
1071 waitproc(int block, int *status)
1072 {
1073         int flags;
1074
1075 #if JOBS
1076         flags = WUNTRACED;
1077 #else
1078         flags = 0;
1079 #endif
1080         if (block == 0)
1081                 flags |= WNOHANG;
1082         return wait3(status, flags, NULL);
1083 }
1084
1085 /*
1086  * return 1 if there are stopped jobs, otherwise 0
1087  */
1088 int job_warning = 0;
1089 int
1090 stoppedjobs(void)
1091 {
1092         int jobno;
1093         struct job *jp;
1094
1095         if (job_warning)
1096                 return (0);
1097         for (jobno = 1, jp = jobtab; jobno <= njobs; jobno++, jp++) {
1098                 if (jp->used == 0)
1099                         continue;
1100                 if (jp->state == JOBSTOPPED) {
1101                         out2fmt_flush("You have stopped jobs.\n");
1102                         job_warning = 2;
1103                         return (1);
1104                 }
1105         }
1106
1107         return (0);
1108 }
1109
1110
1111 static void
1112 checkzombies(void)
1113 {
1114         while (njobs > 0 && dowait(0, NULL) > 0)
1115                 ;
1116 }
1117
1118
1119 int
1120 backgndpidset(void)
1121 {
1122         return backgndpid != -1;
1123 }
1124
1125
1126 pid_t
1127 backgndpidval(void)
1128 {
1129         if (bgjob != NULL && !forcelocal)
1130                 bgjob->remembered = 1;
1131         return backgndpid;
1132 }
1133
1134 /*
1135  * Return a string identifying a command (to be printed by the
1136  * jobs command.
1137  */
1138
1139 static char *cmdnextc;
1140 static int cmdnleft;
1141 #define MAXCMDTEXT      200
1142
1143 char *
1144 commandtext(union node *n)
1145 {
1146         char *name;
1147
1148         cmdnextc = name = ckmalloc(MAXCMDTEXT);
1149         cmdnleft = MAXCMDTEXT - 4;
1150         cmdtxt(n);
1151         *cmdnextc = '\0';
1152         return name;
1153 }
1154
1155
1156 static void
1157 cmdtxt(union node *n)
1158 {
1159         union node *np;
1160         struct nodelist *lp;
1161         const char *p;
1162         int i;
1163         char s[2];
1164
1165         if (n == NULL)
1166                 return;
1167         switch (n->type) {
1168         case NSEMI:
1169                 cmdtxt(n->nbinary.ch1);
1170                 cmdputs("; ");
1171                 cmdtxt(n->nbinary.ch2);
1172                 break;
1173         case NAND:
1174                 cmdtxt(n->nbinary.ch1);
1175                 cmdputs(" && ");
1176                 cmdtxt(n->nbinary.ch2);
1177                 break;
1178         case NOR:
1179                 cmdtxt(n->nbinary.ch1);
1180                 cmdputs(" || ");
1181                 cmdtxt(n->nbinary.ch2);
1182                 break;
1183         case NPIPE:
1184                 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) {
1185                         cmdtxt(lp->n);
1186                         if (lp->next)
1187                                 cmdputs(" | ");
1188                 }
1189                 break;
1190         case NSUBSHELL:
1191                 cmdputs("(");
1192                 cmdtxt(n->nredir.n);
1193                 cmdputs(")");
1194                 break;
1195         case NREDIR:
1196         case NBACKGND:
1197                 cmdtxt(n->nredir.n);
1198                 break;
1199         case NIF:
1200                 cmdputs("if ");
1201                 cmdtxt(n->nif.test);
1202                 cmdputs("; then ");
1203                 cmdtxt(n->nif.ifpart);
1204                 cmdputs("...");
1205                 break;
1206         case NWHILE:
1207                 cmdputs("while ");
1208                 goto until;
1209         case NUNTIL:
1210                 cmdputs("until ");
1211 until:
1212                 cmdtxt(n->nbinary.ch1);
1213                 cmdputs("; do ");
1214                 cmdtxt(n->nbinary.ch2);
1215                 cmdputs("; done");
1216                 break;
1217         case NFOR:
1218                 cmdputs("for ");
1219                 cmdputs(n->nfor.var);
1220                 cmdputs(" in ...");
1221                 break;
1222         case NCASE:
1223                 cmdputs("case ");
1224                 cmdputs(n->ncase.expr->narg.text);
1225                 cmdputs(" in ...");
1226                 break;
1227         case NDEFUN:
1228                 cmdputs(n->narg.text);
1229                 cmdputs("() ...");
1230                 break;
1231         case NCMD:
1232                 for (np = n->ncmd.args ; np ; np = np->narg.next) {
1233                         cmdtxt(np);
1234                         if (np->narg.next)
1235                                 cmdputs(" ");
1236                 }
1237                 for (np = n->ncmd.redirect ; np ; np = np->nfile.next) {
1238                         cmdputs(" ");
1239                         cmdtxt(np);
1240                 }
1241                 break;
1242         case NARG:
1243                 cmdputs(n->narg.text);
1244                 break;
1245         case NTO:
1246                 p = ">";  i = 1;  goto redir;
1247         case NAPPEND:
1248                 p = ">>";  i = 1;  goto redir;
1249         case NTOFD:
1250                 p = ">&";  i = 1;  goto redir;
1251         case NCLOBBER:
1252                 p = ">|"; i = 1; goto redir;
1253         case NFROM:
1254                 p = "<";  i = 0;  goto redir;
1255         case NFROMTO:
1256                 p = "<>";  i = 0;  goto redir;
1257         case NFROMFD:
1258                 p = "<&";  i = 0;  goto redir;
1259 redir:
1260                 if (n->nfile.fd != i) {
1261                         s[0] = n->nfile.fd + '0';
1262                         s[1] = '\0';
1263                         cmdputs(s);
1264                 }
1265                 cmdputs(p);
1266                 if (n->type == NTOFD || n->type == NFROMFD) {
1267                         if (n->ndup.dupfd >= 0)
1268                                 s[0] = n->ndup.dupfd + '0';
1269                         else
1270                                 s[0] = '-';
1271                         s[1] = '\0';
1272                         cmdputs(s);
1273                 } else {
1274                         cmdtxt(n->nfile.fname);
1275                 }
1276                 break;
1277         case NHERE:
1278         case NXHERE:
1279                 cmdputs("<<...");
1280                 break;
1281         default:
1282                 cmdputs("???");
1283                 break;
1284         }
1285 }
1286
1287
1288
1289 static void
1290 cmdputs(const char *s)
1291 {
1292         const char *p;
1293         char *q;
1294         char c;
1295         int subtype = 0;
1296
1297         if (cmdnleft <= 0)
1298                 return;
1299         p = s;
1300         q = cmdnextc;
1301         while ((c = *p++) != '\0') {
1302                 if (c == CTLESC)
1303                         *q++ = *p++;
1304                 else if (c == CTLVAR) {
1305                         *q++ = '$';
1306                         if (--cmdnleft > 0)
1307                                 *q++ = '{';
1308                         subtype = *p++;
1309                         if ((subtype & VSTYPE) == VSLENGTH && --cmdnleft > 0)
1310                                 *q++ = '#';
1311                 } else if (c == '=' && subtype != 0) {
1312                         *q = "}-+?=##%%\0X"[(subtype & VSTYPE) - VSNORMAL];
1313                         if (*q)
1314                                 q++;
1315                         else
1316                                 cmdnleft++;
1317                         if (((subtype & VSTYPE) == VSTRIMLEFTMAX ||
1318                             (subtype & VSTYPE) == VSTRIMRIGHTMAX) &&
1319                             --cmdnleft > 0)
1320                                 *q = q[-1], q++;
1321                         subtype = 0;
1322                 } else if (c == CTLENDVAR) {
1323                         *q++ = '}';
1324                 } else if (c == CTLBACKQ || c == CTLBACKQ+CTLQUOTE) {
1325                         cmdnleft -= 5;
1326                         if (cmdnleft > 0) {
1327                                 *q++ = '$';
1328                                 *q++ = '(';
1329                                 *q++ = '.';
1330                                 *q++ = '.';
1331                                 *q++ = '.';
1332                                 *q++ = ')';
1333                         }
1334                 } else if (c == CTLARI) {
1335                         cmdnleft -= 2;
1336                         if (cmdnleft > 0) {
1337                                 *q++ = '$';
1338                                 *q++ = '(';
1339                                 *q++ = '(';
1340                         }
1341                         p++;
1342                 } else if (c == CTLENDARI) {
1343                         if (--cmdnleft > 0) {
1344                                 *q++ = ')';
1345                                 *q++ = ')';
1346                         }
1347                 } else if (c == CTLQUOTEMARK || c == CTLQUOTEEND)
1348                         cmdnleft++; /* ignore */
1349                 else
1350                         *q++ = c;
1351                 if (--cmdnleft <= 0) {
1352                         *q++ = '.';
1353                         *q++ = '.';
1354                         *q++ = '.';
1355                         break;
1356                 }
1357         }
1358         cmdnextc = q;
1359 }