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 volatile sig_atomic_t breakwaitcmd = 0; /* should wait be terminated? */
  88 static int ttyfd = -1;
  89
  90 /* mode flags for dowait */
  91 #define DOWAIT_BLOCK    0x1 /* wait until a child exits */
  92 #define DOWAIT_SIG      0x2 /* if DOWAIT_BLOCK, abort on signals */
  93
  94 #if JOBS
  95 static void restartjob(struct job *);
  96 #endif
  97 static void freejob(struct job *);
  98 static struct job *getjob(char *);
  99 pid_t getjobpgrp(char *);
 100 static pid_t dowait(int, struct job *);
 101 static void checkzombies(void);
 102 static void cmdtxt(union node *);
 103 static void cmdputs(const char *);
 104 #if JOBS
 105 static void setcurjob(struct job *);
 106 static void deljob(struct job *);
 107 static struct job *getcurjob(struct job *);
 108 #endif
 109 static void printjobcmd(struct job *);
 110 static void showjob(struct job *, int);
 111
 112
 113 /*
 114  * Turn job control on and off.
 115  */
 116
 117 MKINIT int jobctl;
 118
 119 #if JOBS
 120 void
 121 setjobctl(int on)
 122 {
 123         int i;
 124
 125         if (on == jobctl || rootshell == 0)
 126                 return;
 127         if (on) {
 128                 if (ttyfd != -1)
 129                         close(ttyfd);
 130                 if ((ttyfd = open(_PATH_TTY, O_RDWR)) < 0) {
 131                         i = 0;
 132                         while (i <= 2 && !isatty(i))
 133                                 i++;
 134                         if (i > 2 || (ttyfd = fcntl(i, F_DUPFD, 10)) < 0)
 135                                 goto out;
 136                 }
 137                 if (ttyfd < 10) {
 138                         /*
 139                          * Keep our TTY file descriptor out of the way of
 140                          * the user's redirections.
 141                          */
 142                         if ((i = fcntl(ttyfd, F_DUPFD, 10)) < 0) {
 143                                 close(ttyfd);
 144                                 ttyfd = -1;
 145                                 goto out;
 146                         }
 147                         close(ttyfd);
 148                         ttyfd = i;
 149                 }
 150                 if (fcntl(ttyfd, F_SETFD, FD_CLOEXEC) < 0) {
 151                         close(ttyfd);
 152                         ttyfd = -1;
 153                         goto out;
 154                 }
 155                 do { /* while we are in the background */
 156                         initialpgrp = tcgetpgrp(ttyfd);
 157                         if (initialpgrp < 0) {
 158 out:                            out2fmt_flush("sh: can't access tty; job control turned off\n");
 159                                 mflag = 0;
 160                                 return;
 161                         }
 162                         if (initialpgrp != getpgrp()) {
 163                                 kill(0, SIGTTIN);
 164                                 continue;
 165                         }
 166                 } while (0);
 167                 setsignal(SIGTSTP);
 168                 setsignal(SIGTTOU);
 169                 setsignal(SIGTTIN);
 170                 setpgid(0, rootpid);
 171                 tcsetpgrp(ttyfd, rootpid);
 172         } else { /* turning job control off */
 173                 setpgid(0, initialpgrp);
 174                 tcsetpgrp(ttyfd, initialpgrp);
 175                 close(ttyfd);
 176                 ttyfd = -1;
 177                 setsignal(SIGTSTP);
 178                 setsignal(SIGTTOU);
 179                 setsignal(SIGTTIN);
 180         }
 181         jobctl = on;
 182 }
 183 #endif
 184
 185
 186 #if JOBS
 187 int
 188 fgcmd(int argc __unused, char **argv)
 189 {
 190         struct job *jp;
 191         pid_t pgrp;
 192         int status;
 193
 194         jp = getjob(argv[1]);
 195         if (jp->jobctl == 0)
 196                 error("job not created under job control");
 197         printjobcmd(jp);
 198         flushout(&output);
 199         pgrp = jp->ps[0].pid;
 200         tcsetpgrp(ttyfd, pgrp);
 201         restartjob(jp);
 202         jp->foreground = 1;
 203         INTOFF;
 204         status = waitforjob(jp, (int *)NULL);
 205         INTON;
 206         return status;
 207 }
 208
 209
 210 int
 211 bgcmd(int argc, char **argv)
 212 {
 213         struct job *jp;
 214
 215         do {
 216                 jp = getjob(*++argv);
 217                 if (jp->jobctl == 0)
 218                         error("job not created under job control");
 219                 if (jp->state == JOBDONE)
 220                         continue;
 221                 restartjob(jp);
 222                 jp->foreground = 0;
 223                 out1fmt("[%td] ", jp - jobtab + 1);
 224                 printjobcmd(jp);
 225         } while (--argc > 1);
 226         return 0;
 227 }
 228
 229
 230 static void
 231 restartjob(struct job *jp)
 232 {
 233         struct procstat *ps;
 234         int i;
 235
 236         if (jp->state == JOBDONE)
 237                 return;
 238         setcurjob(jp);
 239         INTOFF;
 240         kill(-jp->ps[0].pid, SIGCONT);
 241         for (ps = jp->ps, i = jp->nprocs ; --i >= 0 ; ps++) {
 242                 if (WIFSTOPPED(ps->status)) {
 243                         ps->status = -1;
 244                         jp->state = 0;
 245                 }
 246         }
 247         INTON;
 248 }
 249 #endif
 250
 251
 252 int
 253 jobscmd(int argc __unused, char *argv[] __unused)
 254 {
 255         char *id;
 256         int ch, mode;
 257
 258         mode = SHOWJOBS_DEFAULT;
 259         while ((ch = nextopt("lps")) != '\0') {
 260                 switch (ch) {
 261                 case 'l':
 262                         mode = SHOWJOBS_VERBOSE;
 263                         break;
 264                 case 'p':
 265                         mode = SHOWJOBS_PGIDS;
 266                         break;
 267                 case 's':
 268                         mode = SHOWJOBS_PIDS;
 269                         break;
 270                 }
 271         }
 272
 273         if (*argptr == NULL)
 274                 showjobs(0, mode);
 275         else
 276                 while ((id = *argptr++) != NULL)
 277                         showjob(getjob(id), mode);
 278
 279         return (0);
 280 }
 281
 282 static void
 283 printjobcmd(struct job *jp)
 284 {
 285         struct procstat *ps;
 286         int i;
 287
 288         for (ps = jp->ps, i = jp->nprocs ; --i >= 0 ; ps++) {
 289                 out1str(ps->cmd);
 290                 if (i > 0)
 291                         out1str(" | ");
 292         }
 293         out1c('\n');
 294 }
 295
 296 static void
 297 showjob(struct job *jp, int mode)
 298 {
 299         char s[64];
 300         char statestr[64];
 301         const char *sigstr;
 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                 sigstr = strsignal(i);
 329                 if (sigstr != NULL)
 330                         strcpy(statestr, sigstr);
 331                 else
 332                         strcpy(statestr, "Suspended");
 333 #endif
 334         } else if (WIFEXITED(ps->status)) {
 335                 if (WEXITSTATUS(ps->status) == 0)
 336                         strcpy(statestr, "Done");
 337                 else
 338                         fmtstr(statestr, 64, "Done(%d)",
 339                             WEXITSTATUS(ps->status));
 340         } else {
 341                 i = WTERMSIG(ps->status);
 342                 sigstr = strsignal(i);
 343                 if (sigstr != NULL)
 344                         strcpy(statestr, sigstr);
 345                 else
 346                         strcpy(statestr, "Unknown signal");
 347                 if (WCOREDUMP(ps->status))
 348                         strcat(statestr, " (core dumped)");
 349         }
 350
 351         for (ps = jp->ps ; ; ps++) {    /* for each process */
 352                 if (mode == SHOWJOBS_PIDS || mode == SHOWJOBS_PGIDS) {
 353                         out1fmt("%d\n", (int)ps->pid);
 354                         goto skip;
 355                 }
 356                 if (mode != SHOWJOBS_VERBOSE && ps != jp->ps)
 357                         goto skip;
 358                 if (jobno == curr && ps == jp->ps)
 359                         c = '+';
 360                 else if (jobno == prev && ps == jp->ps)
 361                         c = '-';
 362                 else
 363                         c = ' ';
 364                 if (ps == jp->ps)
 365                         fmtstr(s, 64, "[%d] %c ", jobno, c);
 366                 else
 367                         fmtstr(s, 64, "    %c ", c);
 368                 out1str(s);
 369                 col = strlen(s);
 370                 if (mode == SHOWJOBS_VERBOSE) {
 371                         fmtstr(s, 64, "%d ", (int)ps->pid);
 372                         out1str(s);
 373                         col += strlen(s);
 374                 }
 375                 if (ps == jp->ps) {
 376                         out1str(statestr);
 377                         col += strlen(statestr);
 378                 }
 379                 do {
 380                         out1c(' ');
 381                         col++;
 382                 } while (col < 30);
 383                 if (mode == SHOWJOBS_VERBOSE) {
 384                         out1str(ps->cmd);
 385                         out1c('\n');
 386                 } else
 387                         printjobcmd(jp);
 388 skip:           if (--procno <= 0)
 389                         break;
 390         }
 391 }
 392
 393 /*
 394  * Print a list of jobs.  If "change" is nonzero, only print jobs whose
 395  * statuses have changed since the last call to showjobs.
 396  *
 397  * If the shell is interrupted in the process of creating a job, the
 398  * result may be a job structure containing zero processes.  Such structures
 399  * will be freed here.
 400  */
 401
 402 void
 403 showjobs(int change, int mode)
 404 {
 405         int jobno;
 406         struct job *jp;
 407
 408         TRACE(("showjobs(%d) called\n", change));
 409         checkzombies();
 410         for (jobno = 1, jp = jobtab ; jobno <= njobs ; jobno++, jp++) {
 411                 if (! jp->used)
 412                         continue;
 413                 if (jp->nprocs == 0) {
 414                         freejob(jp);
 415                         continue;
 416                 }
 417                 if (change && ! jp->changed)
 418                         continue;
 419                 showjob(jp, mode);
 420                 jp->changed = 0;
 421                 /* Hack: discard jobs for which $! has not been referenced
 422                  * in interactive mode when they terminate.
 423                  */
 424                 if (jp->state == JOBDONE && !jp->remembered &&
 425                                 (iflag || jp != bgjob)) {
 426                         freejob(jp);
 427                 }
 428         }
 429 }
 430
 431
 432 /*
 433  * Mark a job structure as unused.
 434  */
 435
 436 static void
 437 freejob(struct job *jp)
 438 {
 439         struct procstat *ps;
 440         int i;
 441
 442         INTOFF;
 443         if (bgjob == jp)
 444                 bgjob = NULL;
 445         for (i = jp->nprocs, ps = jp->ps ; --i >= 0 ; ps++) {
 446                 if (ps->cmd != nullstr)
 447                         ckfree(ps->cmd);
 448         }
 449         if (jp->ps != &jp->ps0)
 450                 ckfree(jp->ps);
 451         jp->used = 0;
 452 #if JOBS
 453         deljob(jp);
 454 #endif
 455         INTON;
 456 }
 457
 458
 459
 460 int
 461 waitcmd(int argc, char **argv)
 462 {
 463         struct job *job;
 464         int status, retval;
 465         struct job *jp;
 466
 467         if (argc > 1) {
 468                 job = getjob(argv[1]);
 469         } else {
 470                 job = NULL;
 471         }
 472
 473         /*
 474          * Loop until a process is terminated or stopped, or a SIGINT is
 475          * received.
 476          */
 477
 478         in_waitcmd++;
 479         do {
 480                 if (job != NULL) {
 481                         if (job->state) {
 482                                 status = job->ps[job->nprocs - 1].status;
 483                                 if (WIFEXITED(status))
 484                                         retval = WEXITSTATUS(status);
 485 #if JOBS
 486                                 else if (WIFSTOPPED(status))
 487                                         retval = WSTOPSIG(status) + 128;
 488 #endif
 489                                 else
 490                                         retval = WTERMSIG(status) + 128;
 491                                 if (! iflag || ! job->changed)
 492                                         freejob(job);
 493                                 else {
 494                                         job->remembered = 0;
 495                                         if (job == bgjob)
 496                                                 bgjob = NULL;
 497                                 }
 498                                 in_waitcmd--;
 499                                 return retval;
 500                         }
 501                 } else {
 502                         for (jp = jobtab ; jp < jobtab + njobs; jp++)
 503                                 if (jp->used && jp->state == JOBDONE) {
 504                                         if (! iflag || ! jp->changed)
 505                                                 freejob(jp);
 506                                         else {
 507                                                 jp->remembered = 0;
 508                                                 if (jp == bgjob)
 509                                                         bgjob = NULL;
 510                                         }
 511                                 }
 512                         for (jp = jobtab ; ; jp++) {
 513                                 if (jp >= jobtab + njobs) {     /* no running procs */
 514                                         in_waitcmd--;
 515                                         return 0;
 516                                 }
 517                                 if (jp->used && jp->state == 0)
 518                                         break;
 519                         }
 520                 }
 521         } while (dowait(DOWAIT_BLOCK | DOWAIT_SIG, (struct job *)NULL) != -1);
 522         in_waitcmd--;
 523
 524         return pendingsig + 128;
 525 }
 526
 527
 528
 529 int
 530 jobidcmd(int argc __unused, char **argv)
 531 {
 532         struct job *jp;
 533         int i;
 534
 535         jp = getjob(argv[1]);
 536         for (i = 0 ; i < jp->nprocs ; ) {
 537                 out1fmt("%d", (int)jp->ps[i].pid);
 538                 out1c(++i < jp->nprocs? ' ' : '\n');
 539         }
 540         return 0;
 541 }
 542
 543
 544
 545 /*
 546  * Convert a job name to a job structure.
 547  */
 548
 549 static struct job *
 550 getjob(char *name)
 551 {
 552         int jobno;
 553         struct job *found, *jp;
 554         pid_t pid;
 555         int i;
 556
 557         if (name == NULL) {
 558 #if JOBS
 559 currentjob:     if ((jp = getcurjob(NULL)) == NULL)
 560                         error("No current job");
 561                 return (jp);
 562 #else
 563                 error("No current job");
 564 #endif
 565         } else if (name[0] == '%') {
 566                 if (is_digit(name[1])) {
 567                         jobno = number(name + 1);
 568                         if (jobno > 0 && jobno <= njobs
 569                          && jobtab[jobno - 1].used != 0)
 570                                 return &jobtab[jobno - 1];
 571 #if JOBS
 572                 } else if (name[1] == '%' && name[2] == '\0') {
 573                         goto currentjob;
 574                 } else if (name[1] == '+' && name[2] == '\0') {
 575                         goto currentjob;
 576                 } else if (name[1] == '-' && name[2] == '\0') {
 577                         if ((jp = getcurjob(NULL)) == NULL ||
 578                             (jp = getcurjob(jp)) == NULL)
 579                                 error("No previous job");
 580                         return (jp);
 581 #endif
 582                 } else if (name[1] == '?') {
 583                         found = NULL;
 584                         for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
 585                                 if (jp->used && jp->nprocs > 0
 586                                  && strstr(jp->ps[0].cmd, name + 2) != NULL) {
 587                                         if (found)
 588                                                 error("%s: ambiguous", name);
 589                                         found = jp;
 590                                 }
 591                         }
 592                         if (found != NULL)
 593                                 return (found);
 594                 } else {
 595                         found = NULL;
 596                         for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
 597                                 if (jp->used && jp->nprocs > 0
 598                                  && prefix(name + 1, jp->ps[0].cmd)) {
 599                                         if (found)
 600                                                 error("%s: ambiguous", name);
 601                                         found = jp;
 602                                 }
 603                         }
 604                         if (found)
 605                                 return found;
 606                 }
 607         } else if (is_number(name)) {
 608                 pid = (pid_t)number(name);
 609                 for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
 610                         if (jp->used && jp->nprocs > 0
 611                          && jp->ps[jp->nprocs - 1].pid == pid)
 612                                 return jp;
 613                 }
 614         }
 615         error("No such job: %s", name);
 616         /*NOTREACHED*/
 617         return NULL;
 618 }
 619
 620
 621 pid_t
 622 getjobpgrp(char *name)
 623 {
 624         struct job *jp;
 625
 626         jp = getjob(name);
 627         return -jp->ps[0].pid;
 628 }
 629
 630 /*
 631  * Return a new job structure,
 632  */
 633
 634 struct job *
 635 makejob(union node *node __unused, int nprocs)
 636 {
 637         int i;
 638         struct job *jp;
 639
 640         for (i = njobs, jp = jobtab ; ; jp++) {
 641                 if (--i < 0) {
 642                         INTOFF;
 643                         if (njobs == 0) {
 644                                 jobtab = ckmalloc(4 * sizeof jobtab[0]);
 645 #if JOBS
 646                                 jobmru = NULL;
 647 #endif
 648                         } else {
 649                                 jp = ckmalloc((njobs + 4) * sizeof jobtab[0]);
 650                                 memcpy(jp, jobtab, njobs * sizeof jp[0]);
 651 #if JOBS
 652                                 /* Relocate `next' pointers and list head */
 653                                 if (jobmru != NULL)
 654                                         jobmru = &jp[jobmru - jobtab];
 655                                 for (i = 0; i < njobs; i++)
 656                                         if (jp[i].next != NULL)
 657                                                 jp[i].next = &jp[jp[i].next -
 658                                                     jobtab];
 659 #endif
 660                                 if (bgjob != NULL)
 661                                         bgjob = &jp[bgjob - jobtab];
 662                                 /* Relocate `ps' pointers */
 663                                 for (i = 0; i < njobs; i++)
 664                                         if (jp[i].ps == &jobtab[i].ps0)
 665                                                 jp[i].ps = &jp[i].ps0;
 666                                 ckfree(jobtab);
 667                                 jobtab = jp;
 668                         }
 669                         jp = jobtab + njobs;
 670                         for (i = 4 ; --i >= 0 ; jobtab[njobs++].used = 0);
 671                         INTON;
 672                         break;
 673                 }
 674                 if (jp->used == 0)
 675                         break;
 676         }
 677         INTOFF;
 678         jp->state = 0;
 679         jp->used = 1;
 680         jp->changed = 0;
 681         jp->nprocs = 0;
 682         jp->foreground = 0;
 683         jp->remembered = 0;
 684 #if JOBS
 685         jp->jobctl = jobctl;
 686         jp->next = NULL;
 687 #endif
 688         if (nprocs > 1) {
 689                 jp->ps = ckmalloc(nprocs * sizeof (struct procstat));
 690         } else {
 691                 jp->ps = &jp->ps0;
 692         }
 693         INTON;
 694         TRACE(("makejob(%p, %d) returns %%%td\n", (void *)node, nprocs,
 695             jp - jobtab + 1));
 696         return jp;
 697 }
 698
 699 #if JOBS
 700 static void
 701 setcurjob(struct job *cj)
 702 {
 703         struct job *jp, *prev;
 704
 705         for (prev = NULL, jp = jobmru; jp != NULL; prev = jp, jp = jp->next) {
 706                 if (jp == cj) {
 707                         if (prev != NULL)
 708                                 prev->next = jp->next;
 709                         else
 710                                 jobmru = jp->next;
 711                         jp->next = jobmru;
 712                         jobmru = cj;
 713                         return;
 714                 }
 715         }
 716         cj->next = jobmru;
 717         jobmru = cj;
 718 }
 719
 720 static void
 721 deljob(struct job *j)
 722 {
 723         struct job *jp, *prev;
 724
 725         for (prev = NULL, jp = jobmru; jp != NULL; prev = jp, jp = jp->next) {
 726                 if (jp == j) {
 727                         if (prev != NULL)
 728                                 prev->next = jp->next;
 729                         else
 730                                 jobmru = jp->next;
 731                         return;
 732                 }
 733         }
 734 }
 735
 736 /*
 737  * Return the most recently used job that isn't `nj', and preferably one
 738  * that is stopped.
 739  */
 740 static struct job *
 741 getcurjob(struct job *nj)
 742 {
 743         struct job *jp;
 744
 745         /* Try to find a stopped one.. */
 746         for (jp = jobmru; jp != NULL; jp = jp->next)
 747                 if (jp->used && jp != nj && jp->state == JOBSTOPPED)
 748                         return (jp);
 749         /* Otherwise the most recently used job that isn't `nj' */
 750         for (jp = jobmru; jp != NULL; jp = jp->next)
 751                 if (jp->used && jp != nj)
 752                         return (jp);
 753
 754         return (NULL);
 755 }
 756
 757 #endif
 758
 759 /*
 760  * Fork of a subshell.  If we are doing job control, give the subshell its
 761  * own process group.  Jp is a job structure that the job is to be added to.
 762  * N is the command that will be evaluated by the child.  Both jp and n may
 763  * be NULL.  The mode parameter can be one of the following:
 764  *      FORK_FG - Fork off a foreground process.
 765  *      FORK_BG - Fork off a background process.
 766  *      FORK_NOJOB - Like FORK_FG, but don't give the process its own
 767  *                   process group even if job control is on.
 768  *
 769  * When job control is turned off, background processes have their standard
 770  * input redirected to /dev/null (except for the second and later processes
 771  * in a pipeline).
 772  */
 773
 774 pid_t
 775 forkshell(struct job *jp, union node *n, int mode)
 776 {
 777         pid_t pid;
 778         pid_t pgrp;
 779
 780         TRACE(("forkshell(%%%td, %p, %d) called\n", jp - jobtab, (void *)n,
 781             mode));
 782         INTOFF;
 783         if (mode == FORK_BG && (jp == NULL || jp->nprocs == 0))
 784                 checkzombies();
 785         flushall();
 786         pid = fork();
 787         if (pid == -1) {
 788                 TRACE(("Fork failed, errno=%d\n", errno));
 789                 INTON;
 790                 error("Cannot fork: %s", strerror(errno));
 791         }
 792         if (pid == 0) {
 793                 struct job *p;
 794                 int wasroot;
 795                 int i;
 796
 797                 TRACE(("Child shell %d\n", (int)getpid()));
 798                 wasroot = rootshell;
 799                 rootshell = 0;
 800                 handler = &main_handler;
 801                 closescript();
 802                 INTON;
 803                 forcelocal = 0;
 804                 clear_traps();
 805 #if JOBS
 806                 jobctl = 0;             /* do job control only in root shell */
 807                 if (wasroot && mode != FORK_NOJOB && mflag) {
 808                         if (jp == NULL || jp->nprocs == 0)
 809                                 pgrp = getpid();
 810                         else
 811                                 pgrp = jp->ps[0].pid;
 812                         if (setpgid(0, pgrp) == 0 && mode == FORK_FG) {
 813                                 /*** this causes superfluous TIOCSPGRPS ***/
 814                                 if (tcsetpgrp(ttyfd, pgrp) < 0)
 815                                         error("tcsetpgrp failed, errno=%d", errno);
 816                         }
 817                         setsignal(SIGTSTP);
 818                         setsignal(SIGTTOU);
 819                 } else if (mode == FORK_BG) {
 820                         ignoresig(SIGINT);
 821                         ignoresig(SIGQUIT);
 822                         if ((jp == NULL || jp->nprocs == 0) &&
 823                             ! fd0_redirected_p ()) {
 824                                 close(0);
 825                                 if (open(_PATH_DEVNULL, O_RDONLY) != 0)
 826                                         error("cannot open %s: %s",
 827                                             _PATH_DEVNULL, strerror(errno));
 828                         }
 829                 }
 830 #else
 831                 if (mode == FORK_BG) {
 832                         ignoresig(SIGINT);
 833                         ignoresig(SIGQUIT);
 834                         if ((jp == NULL || jp->nprocs == 0) &&
 835                             ! fd0_redirected_p ()) {
 836                                 close(0);
 837                                 if (open(_PATH_DEVNULL, O_RDONLY) != 0)
 838                                         error("cannot open %s: %s",
 839                                             _PATH_DEVNULL, strerror(errno));
 840                         }
 841                 }
 842 #endif
 843                 INTOFF;
 844                 for (i = njobs, p = jobtab ; --i >= 0 ; p++)
 845                         if (p->used)
 846                                 freejob(p);
 847                 INTON;
 848                 if (wasroot && iflag) {
 849                         setsignal(SIGINT);
 850                         setsignal(SIGQUIT);
 851                         setsignal(SIGTERM);
 852                 }
 853                 return pid;
 854         }
 855         if (rootshell && mode != FORK_NOJOB && mflag) {
 856                 if (jp == NULL || jp->nprocs == 0)
 857                         pgrp = pid;
 858                 else
 859                         pgrp = jp->ps[0].pid;
 860                 setpgid(pid, pgrp);
 861         }
 862         if (mode == FORK_BG) {
 863                 if (bgjob != NULL && bgjob->state == JOBDONE &&
 864                     !bgjob->remembered && !iflag)
 865                         freejob(bgjob);
 866                 backgndpid = pid;               /* set $! */
 867                 bgjob = jp;
 868         }
 869         if (jp) {
 870                 struct procstat *ps = &jp->ps[jp->nprocs++];
 871                 ps->pid = pid;
 872                 ps->status = -1;
 873                 ps->cmd = nullstr;
 874                 if (iflag && rootshell && n)
 875                         ps->cmd = commandtext(n);
 876                 jp->foreground = mode == FORK_FG;
 877 #if JOBS
 878                 setcurjob(jp);
 879 #endif
 880         }
 881         INTON;
 882         TRACE(("In parent shell:  child = %d\n", (int)pid));
 883         return pid;
 884 }
 885
 886
 887 pid_t
 888 vforkexecshell(struct job *jp, char **argv, char **envp, const char *path, int idx, int pip[2])
 889 {
 890         pid_t pid;
 891         struct jmploc jmploc;
 892         struct jmploc *savehandler;
 893
 894         TRACE(("vforkexecshell(%%%td, %s, %p) called\n", jp - jobtab, argv[0],
 895             (void *)pip));
 896         INTOFF;
 897         flushall();
 898         savehandler = handler;
 899         pid = vfork();
 900         if (pid == -1) {
 901                 TRACE(("Vfork failed, errno=%d\n", errno));
 902                 INTON;
 903                 error("Cannot fork: %s", strerror(errno));
 904         }
 905         if (pid == 0) {
 906                 TRACE(("Child shell %d\n", (int)getpid()));
 907                 if (setjmp(jmploc.loc))
 908                         _exit(exception == EXEXEC ? exerrno : 2);
 909                 if (pip != NULL) {
 910                         close(pip[0]);
 911                         if (pip[1] != 1) {
 912                                 dup2(pip[1], 1);
 913                                 close(pip[1]);
 914                         }
 915                 }
 916                 handler = &jmploc;
 917                 shellexec(argv, envp, path, idx);
 918         }
 919         handler = savehandler;
 920         if (jp) {
 921                 struct procstat *ps = &jp->ps[jp->nprocs++];
 922                 ps->pid = pid;
 923                 ps->status = -1;
 924                 ps->cmd = nullstr;
 925                 jp->foreground = 1;
 926 #if JOBS
 927                 setcurjob(jp);
 928 #endif
 929         }
 930         INTON;
 931         TRACE(("In parent shell:  child = %d\n", (int)pid));
 932         return pid;
 933 }
 934
 935
 936 /*
 937  * Wait for job to finish.
 938  *
 939  * Under job control we have the problem that while a child process is
 940  * running interrupts generated by the user are sent to the child but not
 941  * to the shell.  This means that an infinite loop started by an inter-
 942  * active user may be hard to kill.  With job control turned off, an
 943  * interactive user may place an interactive program inside a loop.  If
 944  * the interactive program catches interrupts, the user doesn't want
 945  * these interrupts to also abort the loop.  The approach we take here
 946  * is to have the shell ignore interrupt signals while waiting for a
 947  * foreground process to terminate, and then send itself an interrupt
 948  * signal if the child process was terminated by an interrupt signal.
 949  * Unfortunately, some programs want to do a bit of cleanup and then
 950  * exit on interrupt; unless these processes terminate themselves by
 951  * sending a signal to themselves (instead of calling exit) they will
 952  * confuse this approach.
 953  */
 954
 955 int
 956 waitforjob(struct job *jp, int *origstatus)
 957 {
 958 #if JOBS
 959         pid_t mypgrp = getpgrp();
 960         int propagate_int = jp->jobctl && jp->foreground;
 961 #endif
 962         int status;
 963         int st;
 964
 965         INTOFF;
 966         TRACE(("waitforjob(%%%td) called\n", jp - jobtab + 1));
 967         while (jp->state == 0)
 968                 if (dowait(DOWAIT_BLOCK | (Tflag ? DOWAIT_SIG : 0), jp) == -1)
 969                         dotrap();
 970 #if JOBS
 971         if (jp->jobctl) {
 972                 if (tcsetpgrp(ttyfd, mypgrp) < 0)
 973                         error("tcsetpgrp failed, errno=%d\n", errno);
 974         }
 975         if (jp->state == JOBSTOPPED)
 976                 setcurjob(jp);
 977 #endif
 978         status = jp->ps[jp->nprocs - 1].status;
 979         if (origstatus != NULL)
 980                 *origstatus = status;
 981         /* convert to 8 bits */
 982         if (WIFEXITED(status))
 983                 st = WEXITSTATUS(status);
 984 #if JOBS
 985         else if (WIFSTOPPED(status))
 986                 st = WSTOPSIG(status) + 128;
 987 #endif
 988         else
 989                 st = WTERMSIG(status) + 128;
 990         if (! JOBS || jp->state == JOBDONE)
 991                 freejob(jp);
 992         if (int_pending()) {
 993                 if (!WIFSIGNALED(status) || WTERMSIG(status) != SIGINT)
 994                         CLEAR_PENDING_INT;
 995         }
 996 #if JOBS
 997         else if (rootshell && iflag && propagate_int &&
 998                         WIFSIGNALED(status) && WTERMSIG(status) == SIGINT)
 999                 kill(getpid(), SIGINT);
1000 #endif
1001         INTON;
1002         return st;
1003 }
1004
1005
1006 static void
1007 dummy_handler(int sig)
1008 {
1009 }
1010
1011 /*
1012  * Wait for a process to terminate.
1013  */
1014
1015 static pid_t
1016 dowait(int mode, struct job *job)
1017 {
1018         struct sigaction sa, osa;
1019         sigset_t mask, omask;
1020         pid_t pid;
1021         int status;
1022         struct procstat *sp;
1023         struct job *jp;
1024         struct job *thisjob;
1025         const char *sigstr;
1026         int done;
1027         int stopped;
1028         int sig;
1029         int coredump;
1030         int wflags;
1031         int restore_sigchld;
1032
1033         TRACE(("dowait(%d, %p) called\n", mode, job));
1034         restore_sigchld = 0;
1035         if ((mode & DOWAIT_SIG) != 0) {
1036                 sigfillset(&mask);
1037                 sigprocmask(SIG_BLOCK, &mask, &omask);
1038                 INTOFF;
1039                 if (!issigchldtrapped()) {
1040                         restore_sigchld = 1;
1041                         sa.sa_handler = dummy_handler;
1042                         sa.sa_flags = 0;
1043                         sigemptyset(&sa.sa_mask);
1044                         sigaction(SIGCHLD, &sa, &osa);
1045                 }
1046         }
1047         do {
1048 #if JOBS
1049                 if (iflag)
1050                         wflags = WUNTRACED | WCONTINUED;
1051                 else
1052 #endif
1053                         wflags = 0;
1054                 if ((mode & (DOWAIT_BLOCK | DOWAIT_SIG)) != DOWAIT_BLOCK)
1055                         wflags |= WNOHANG;
1056                 pid = wait3(&status, wflags, (struct rusage *)NULL);
1057                 TRACE(("wait returns %d, status=%d\n", (int)pid, status));
1058                 if (pid == 0 && (mode & DOWAIT_SIG) != 0) {
1059                         sigsuspend(&omask);
1060                         pid = -1;
1061                         if (int_pending())
1062                                 break;
1063                 }
1064         } while (pid == -1 && errno == EINTR && breakwaitcmd == 0);
1065         if (pid == -1 && errno == ECHILD && job != NULL)
1066                 job->state = JOBDONE;
1067         if ((mode & DOWAIT_SIG) != 0) {
1068                 if (restore_sigchld)
1069                         sigaction(SIGCHLD, &osa, NULL);
1070                 sigprocmask(SIG_SETMASK, &omask, NULL);
1071                 INTON;
1072         }
1073         if (breakwaitcmd != 0) {
1074                 breakwaitcmd = 0;
1075                 if (pid <= 0)
1076                         return -1;
1077         }
1078         if (pid <= 0)
1079                 return pid;
1080         INTOFF;
1081         thisjob = NULL;
1082         for (jp = jobtab ; jp < jobtab + njobs ; jp++) {
1083                 if (jp->used && jp->nprocs > 0) {
1084                         done = 1;
1085                         stopped = 1;
1086                         for (sp = jp->ps ; sp < jp->ps + jp->nprocs ; sp++) {
1087                                 if (sp->pid == -1)
1088                                         continue;
1089                                 if (sp->pid == pid) {
1090                                         TRACE(("Changing status of proc %d from 0x%x to 0x%x\n",
1091                                                    (int)pid, sp->status,
1092                                                    status));
1093                                         if (WIFCONTINUED(status)) {
1094                                                 sp->status = -1;
1095                                                 jp->state = 0;
1096                                         } else
1097                                                 sp->status = status;
1098                                         thisjob = jp;
1099                                 }
1100                                 if (sp->status == -1)
1101                                         stopped = 0;
1102                                 else if (WIFSTOPPED(sp->status))
1103                                         done = 0;
1104                         }
1105                         if (stopped) {          /* stopped or done */
1106                                 int state = done? JOBDONE : JOBSTOPPED;
1107                                 if (jp->state != state) {
1108                                         TRACE(("Job %td: changing state from %d to %d\n", jp - jobtab + 1, jp->state, state));
1109                                         jp->state = state;
1110                                         if (jp != job) {
1111                                                 if (done && !jp->remembered &&
1112                                                     !iflag && jp != bgjob)
1113                                                         freejob(jp);
1114 #if JOBS
1115                                                 else if (done)
1116                                                         deljob(jp);
1117 #endif
1118                                         }
1119                                 }
1120                         }
1121                 }
1122         }
1123         INTON;
1124         if (!thisjob || thisjob->state == 0)
1125                 ;
1126         else if ((!rootshell || !iflag || thisjob == job) &&
1127             thisjob->foreground && thisjob->state != JOBSTOPPED) {
1128                 sig = 0;
1129                 coredump = 0;
1130                 for (sp = thisjob->ps; sp < thisjob->ps + thisjob->nprocs; sp++)
1131                         if (WIFSIGNALED(sp->status)) {
1132                                 sig = WTERMSIG(sp->status);
1133                                 coredump = WCOREDUMP(sp->status);
1134                         }
1135                 if (sig > 0 && sig != SIGINT && sig != SIGPIPE) {
1136                         sigstr = strsignal(sig);
1137                         if (sigstr != NULL)
1138                                 out2str(sigstr);
1139                         else
1140                                 out2str("Unknown signal");
1141                         if (coredump)
1142                                 out2str(" (core dumped)");
1143                         out2c('\n');
1144                         flushout(out2);
1145                 }
1146         } else {
1147                 TRACE(("Not printing status, rootshell=%d, job=%p\n", rootshell, job));
1148                 thisjob->changed = 1;
1149         }
1150         return pid;
1151 }
1152
1153
1154
1155 /*
1156  * return 1 if there are stopped jobs, otherwise 0
1157  */
1158 int job_warning = 0;
1159 int
1160 stoppedjobs(void)
1161 {
1162         int jobno;
1163         struct job *jp;
1164
1165         if (job_warning)
1166                 return (0);
1167         for (jobno = 1, jp = jobtab; jobno <= njobs; jobno++, jp++) {
1168                 if (jp->used == 0)
1169                         continue;
1170                 if (jp->state == JOBSTOPPED) {
1171                         out2fmt_flush("You have stopped jobs.\n");
1172                         job_warning = 2;
1173                         return (1);
1174                 }
1175         }
1176
1177         return (0);
1178 }
1179
1180
1181 static void
1182 checkzombies(void)
1183 {
1184         while (njobs > 0 && dowait(0, NULL) > 0)
1185                 ;
1186 }
1187
1188
1189 int
1190 backgndpidset(void)
1191 {
1192         return backgndpid != -1;
1193 }
1194
1195
1196 pid_t
1197 backgndpidval(void)
1198 {
1199         if (bgjob != NULL && !forcelocal)
1200                 bgjob->remembered = 1;
1201         return backgndpid;
1202 }
1203
1204 /*
1205  * Return a string identifying a command (to be printed by the
1206  * jobs command.
1207  */
1208
1209 static char *cmdnextc;
1210 static int cmdnleft;
1211 #define MAXCMDTEXT      200
1212
1213 char *
1214 commandtext(union node *n)
1215 {
1216         char *name;
1217
1218         cmdnextc = name = ckmalloc(MAXCMDTEXT);
1219         cmdnleft = MAXCMDTEXT - 4;
1220         cmdtxt(n);
1221         *cmdnextc = '\0';
1222         return name;
1223 }
1224
1225
1226 static void
1227 cmdtxt(union node *n)
1228 {
1229         union node *np;
1230         struct nodelist *lp;
1231         const char *p;
1232         int i;
1233         char s[2];
1234
1235         if (n == NULL)
1236                 return;
1237         switch (n->type) {
1238         case NSEMI:
1239                 cmdtxt(n->nbinary.ch1);
1240                 cmdputs("; ");
1241                 cmdtxt(n->nbinary.ch2);
1242                 break;
1243         case NAND:
1244                 cmdtxt(n->nbinary.ch1);
1245                 cmdputs(" && ");
1246                 cmdtxt(n->nbinary.ch2);
1247                 break;
1248         case NOR:
1249                 cmdtxt(n->nbinary.ch1);
1250                 cmdputs(" || ");
1251                 cmdtxt(n->nbinary.ch2);
1252                 break;
1253         case NPIPE:
1254                 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) {
1255                         cmdtxt(lp->n);
1256                         if (lp->next)
1257                                 cmdputs(" | ");
1258                 }
1259                 break;
1260         case NSUBSHELL:
1261                 cmdputs("(");
1262                 cmdtxt(n->nredir.n);
1263                 cmdputs(")");
1264                 break;
1265         case NREDIR:
1266         case NBACKGND:
1267                 cmdtxt(n->nredir.n);
1268                 break;
1269         case NIF:
1270                 cmdputs("if ");
1271                 cmdtxt(n->nif.test);
1272                 cmdputs("; then ");
1273                 cmdtxt(n->nif.ifpart);
1274                 cmdputs("...");
1275                 break;
1276         case NWHILE:
1277                 cmdputs("while ");
1278                 goto until;
1279         case NUNTIL:
1280                 cmdputs("until ");
1281 until:
1282                 cmdtxt(n->nbinary.ch1);
1283                 cmdputs("; do ");
1284                 cmdtxt(n->nbinary.ch2);
1285                 cmdputs("; done");
1286                 break;
1287         case NFOR:
1288                 cmdputs("for ");
1289                 cmdputs(n->nfor.var);
1290                 cmdputs(" in ...");
1291                 break;
1292         case NCASE:
1293                 cmdputs("case ");
1294                 cmdputs(n->ncase.expr->narg.text);
1295                 cmdputs(" in ...");
1296                 break;
1297         case NDEFUN:
1298                 cmdputs(n->narg.text);
1299                 cmdputs("() ...");
1300                 break;
1301         case NNOT:
1302                 cmdputs("! ");
1303                 cmdtxt(n->nnot.com);
1304                 break;
1305         case NCMD:
1306                 for (np = n->ncmd.args ; np ; np = np->narg.next) {
1307                         cmdtxt(np);
1308                         if (np->narg.next)
1309                                 cmdputs(" ");
1310                 }
1311                 for (np = n->ncmd.redirect ; np ; np = np->nfile.next) {
1312                         cmdputs(" ");
1313                         cmdtxt(np);
1314                 }
1315                 break;
1316         case NARG:
1317                 cmdputs(n->narg.text);
1318                 break;
1319         case NTO:
1320                 p = ">";  i = 1;  goto redir;
1321         case NAPPEND:
1322                 p = ">>";  i = 1;  goto redir;
1323         case NTOFD:
1324                 p = ">&";  i = 1;  goto redir;
1325         case NCLOBBER:
1326                 p = ">|"; i = 1; goto redir;
1327         case NFROM:
1328                 p = "<";  i = 0;  goto redir;
1329         case NFROMTO:
1330                 p = "<>";  i = 0;  goto redir;
1331         case NFROMFD:
1332                 p = "<&";  i = 0;  goto redir;
1333 redir:
1334                 if (n->nfile.fd != i) {
1335                         s[0] = n->nfile.fd + '0';
1336                         s[1] = '\0';
1337                         cmdputs(s);
1338                 }
1339                 cmdputs(p);
1340                 if (n->type == NTOFD || n->type == NFROMFD) {
1341                         if (n->ndup.dupfd >= 0)
1342                                 s[0] = n->ndup.dupfd + '0';
1343                         else
1344                                 s[0] = '-';
1345                         s[1] = '\0';
1346                         cmdputs(s);
1347                 } else {
1348                         cmdtxt(n->nfile.fname);
1349                 }
1350                 break;
1351         case NHERE:
1352         case NXHERE:
1353                 cmdputs("<<...");
1354                 break;
1355         default:
1356                 cmdputs("???");
1357                 break;
1358         }
1359 }
1360
1361
1362
1363 static void
1364 cmdputs(const char *s)
1365 {
1366         const char *p;
1367         char *q;
1368         char c;
1369         int subtype = 0;
1370
1371         if (cmdnleft <= 0)
1372                 return;
1373         p = s;
1374         q = cmdnextc;
1375         while ((c = *p++) != '\0') {
1376                 if (c == CTLESC)
1377                         *q++ = *p++;
1378                 else if (c == CTLVAR) {
1379                         *q++ = '$';
1380                         if (--cmdnleft > 0)
1381                                 *q++ = '{';
1382                         subtype = *p++;
1383                         if ((subtype & VSTYPE) == VSLENGTH && --cmdnleft > 0)
1384                                 *q++ = '#';
1385                 } else if (c == '=' && subtype != 0) {
1386                         *q = "}-+?=##%%\0X"[(subtype & VSTYPE) - VSNORMAL];
1387                         if (*q)
1388                                 q++;
1389                         else
1390                                 cmdnleft++;
1391                         if (((subtype & VSTYPE) == VSTRIMLEFTMAX ||
1392                             (subtype & VSTYPE) == VSTRIMRIGHTMAX) &&
1393                             --cmdnleft > 0)
1394                                 *q = q[-1], q++;
1395                         subtype = 0;
1396                 } else if (c == CTLENDVAR) {
1397                         *q++ = '}';
1398                 } else if (c == CTLBACKQ || c == CTLBACKQ+CTLQUOTE) {
1399                         cmdnleft -= 5;
1400                         if (cmdnleft > 0) {
1401                                 *q++ = '$';
1402                                 *q++ = '(';
1403                                 *q++ = '.';
1404                                 *q++ = '.';
1405                                 *q++ = '.';
1406                                 *q++ = ')';
1407                         }
1408                 } else if (c == CTLARI) {
1409                         cmdnleft -= 2;
1410                         if (cmdnleft > 0) {
1411                                 *q++ = '$';
1412                                 *q++ = '(';
1413                                 *q++ = '(';
1414                         }
1415                         p++;
1416                 } else if (c == CTLENDARI) {
1417                         if (--cmdnleft > 0) {
1418                                 *q++ = ')';
1419                                 *q++ = ')';
1420                         }
1421                 } else if (c == CTLQUOTEMARK || c == CTLQUOTEEND)
1422                         cmdnleft++; /* ignore */
1423                 else
1424                         *q++ = c;
1425                 if (--cmdnleft <= 0) {
1426                         *q++ = '.';
1427                         *q++ = '.';
1428                         *q++ = '.';
1429                         break;
1430                 }
1431         }
1432         cmdnextc = q;
1433 }