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 static pid_t backgndpid = -1;   /* pid of last background process */
  81 static 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 static int ttyfd = -1;
  87
  88 /* mode flags for dowait */
  89 #define DOWAIT_BLOCK    0x1 /* wait until a child exits */
  90 #define DOWAIT_SIG      0x2 /* if DOWAIT_BLOCK, abort on SIGINT/SIGQUIT */
  91 #define DOWAIT_SIG_ANY  0x4 /* if DOWAIT_SIG, abort on any signal */
  92
  93 #if JOBS
  94 static void restartjob(struct job *);
  95 #endif
  96 static void freejob(struct job *);
  97 static int waitcmdloop(struct job *);
  98 static struct job *getjob_nonotfound(const char *);
  99 static struct job *getjob(const char *);
 100 pid_t killjob(const char *, int);
 101 static pid_t dowait(int, struct job *);
 102 static void checkzombies(void);
 103 static void cmdtxt(union node *);
 104 static void cmdputs(const char *);
 105 #if JOBS
 106 static void setcurjob(struct job *);
 107 static void deljob(struct job *);
 108 static struct job *getcurjob(struct job *);
 109 #endif
 110 static void printjobcmd(struct job *);
 111 static void showjob(struct job *, int);
 112
 113
 114 /*
 115  * Turn job control on and off.
 116  */
 117
 118 static int jobctl;
 119
 120 #if JOBS
 121 static void
 122 jobctl_notty(void)
 123 {
 124         if (ttyfd >= 0) {
 125                 close(ttyfd);
 126                 ttyfd = -1;
 127         }
 128         if (!iflag) {
 129                 setsignal(SIGTSTP);
 130                 setsignal(SIGTTOU);
 131                 setsignal(SIGTTIN);
 132                 jobctl = 1;
 133                 return;
 134         }
 135         out2fmt_flush("sh: can't access tty; job control turned off\n");
 136         mflag = 0;
 137 }
 138
 139 void
 140 setjobctl(int on)
 141 {
 142         int i;
 143
 144         if (on == jobctl || rootshell == 0)
 145                 return;
 146         if (on) {
 147                 if (ttyfd != -1)
 148                         close(ttyfd);
 149                 if ((ttyfd = open(_PATH_TTY, O_RDWR | O_CLOEXEC)) < 0) {
 150                         i = 0;
 151                         while (i <= 2 && !isatty(i))
 152                                 i++;
 153                         if (i > 2 ||
 154                             (ttyfd = fcntl(i, F_DUPFD_CLOEXEC, 10)) < 0) {
 155                                 jobctl_notty();
 156                                 return;
 157                         }
 158                 }
 159                 if (ttyfd < 10) {
 160                         /*
 161                          * Keep our TTY file descriptor out of the way of
 162                          * the user's redirections.
 163                          */
 164                         if ((i = fcntl(ttyfd, F_DUPFD_CLOEXEC, 10)) < 0) {
 165                                 jobctl_notty();
 166                                 return;
 167                         }
 168                         close(ttyfd);
 169                         ttyfd = i;
 170                 }
 171                 do { /* while we are in the background */
 172                         initialpgrp = tcgetpgrp(ttyfd);
 173                         if (initialpgrp < 0) {
 174                                 jobctl_notty();
 175                                 return;
 176                         }
 177                         if (initialpgrp != getpgrp()) {
 178                                 if (!iflag) {
 179                                         initialpgrp = -1;
 180                                         jobctl_notty();
 181                                         return;
 182                                 }
 183                                 kill(0, SIGTTIN);
 184                                 continue;
 185                         }
 186                 } while (0);
 187                 setsignal(SIGTSTP);
 188                 setsignal(SIGTTOU);
 189                 setsignal(SIGTTIN);
 190                 setpgid(0, rootpid);
 191                 tcsetpgrp(ttyfd, rootpid);
 192         } else { /* turning job control off */
 193                 setpgid(0, initialpgrp);
 194                 if (ttyfd >= 0) {
 195                         tcsetpgrp(ttyfd, initialpgrp);
 196                         close(ttyfd);
 197                         ttyfd = -1;
 198                 }
 199                 setsignal(SIGTSTP);
 200                 setsignal(SIGTTOU);
 201                 setsignal(SIGTTIN);
 202         }
 203         jobctl = on;
 204 }
 205 #endif
 206
 207
 208 #if JOBS
 209 int
 210 fgcmd(int argc __unused, char **argv __unused)
 211 {
 212         struct job *jp;
 213         pid_t pgrp;
 214         int status;
 215
 216         nextopt("");
 217         jp = getjob(*argptr);
 218         if (jp->jobctl == 0)
 219                 error("job not created under job control");
 220         printjobcmd(jp);
 221         flushout(&output);
 222         pgrp = jp->ps[0].pid;
 223         if (ttyfd >= 0)
 224                 tcsetpgrp(ttyfd, pgrp);
 225         restartjob(jp);
 226         jp->foreground = 1;
 227         INTOFF;
 228         status = waitforjob(jp, (int *)NULL);
 229         INTON;
 230         return status;
 231 }
 232
 233
 234 int
 235 bgcmd(int argc, char **argv)
 236 {
 237         struct job *jp;
 238
 239         nextopt("");
 240         do {
 241                 jp = getjob(*argptr);
 242                 if (jp->jobctl == 0)
 243                         error("job not created under job control");
 244                 if (jp->state == JOBDONE)
 245                         continue;
 246                 restartjob(jp);
 247                 jp->foreground = 0;
 248                 out1fmt("[%td] ", jp - jobtab + 1);
 249                 printjobcmd(jp);
 250         } while (*argptr != NULL && *++argptr != NULL);
 251         return 0;
 252 }
 253
 254
 255 static void
 256 restartjob(struct job *jp)
 257 {
 258         struct procstat *ps;
 259         int i;
 260
 261         if (jp->state == JOBDONE)
 262                 return;
 263         setcurjob(jp);
 264         INTOFF;
 265         kill(-jp->ps[0].pid, SIGCONT);
 266         for (ps = jp->ps, i = jp->nprocs ; --i >= 0 ; ps++) {
 267                 if (WIFSTOPPED(ps->status)) {
 268                         ps->status = -1;
 269                         jp->state = 0;
 270                 }
 271         }
 272         INTON;
 273 }
 274 #endif
 275
 276
 277 int
 278 jobscmd(int argc __unused, char *argv[] __unused)
 279 {
 280         char *id;
 281         int ch, mode;
 282
 283         mode = SHOWJOBS_DEFAULT;
 284         while ((ch = nextopt("lps")) != '\0') {
 285                 switch (ch) {
 286                 case 'l':
 287                         mode = SHOWJOBS_VERBOSE;
 288                         break;
 289                 case 'p':
 290                         mode = SHOWJOBS_PGIDS;
 291                         break;
 292                 case 's':
 293                         mode = SHOWJOBS_PIDS;
 294                         break;
 295                 }
 296         }
 297
 298         if (*argptr == NULL)
 299                 showjobs(0, mode);
 300         else
 301                 while ((id = *argptr++) != NULL)
 302                         showjob(getjob(id), mode);
 303
 304         return (0);
 305 }
 306
 307 static void
 308 printjobcmd(struct job *jp)
 309 {
 310         struct procstat *ps;
 311         int i;
 312
 313         for (ps = jp->ps, i = jp->nprocs ; --i >= 0 ; ps++) {
 314                 out1str(ps->cmd);
 315                 if (i > 0)
 316                         out1str(" | ");
 317         }
 318         out1c('\n');
 319 }
 320
 321 static void
 322 showjob(struct job *jp, int mode)
 323 {
 324         char s[64];
 325         char statestr[64];
 326         const char *sigstr;
 327         struct procstat *ps;
 328         struct job *j;
 329         int col, curr, i, jobno, prev, procno;
 330         char c;
 331
 332         procno = (mode == SHOWJOBS_PGIDS) ? 1 : jp->nprocs;
 333         jobno = jp - jobtab + 1;
 334         curr = prev = 0;
 335 #if JOBS
 336         if ((j = getcurjob(NULL)) != NULL) {
 337                 curr = j - jobtab + 1;
 338                 if ((j = getcurjob(j)) != NULL)
 339                         prev = j - jobtab + 1;
 340         }
 341 #endif
 342         ps = jp->ps + jp->nprocs - 1;
 343         if (jp->state == 0) {
 344                 strcpy(statestr, "Running");
 345 #if JOBS
 346         } else if (jp->state == JOBSTOPPED) {
 347                 while (!WIFSTOPPED(ps->status) && ps > jp->ps)
 348                         ps--;
 349                 if (WIFSTOPPED(ps->status))
 350                         i = WSTOPSIG(ps->status);
 351                 else
 352                         i = -1;
 353                 sigstr = strsignal(i);
 354                 if (sigstr != NULL)
 355                         strcpy(statestr, sigstr);
 356                 else
 357                         strcpy(statestr, "Suspended");
 358 #endif
 359         } else if (WIFEXITED(ps->status)) {
 360                 if (WEXITSTATUS(ps->status) == 0)
 361                         strcpy(statestr, "Done");
 362                 else
 363                         fmtstr(statestr, 64, "Done(%d)",
 364                             WEXITSTATUS(ps->status));
 365         } else {
 366                 i = WTERMSIG(ps->status);
 367                 sigstr = strsignal(i);
 368                 if (sigstr != NULL)
 369                         strcpy(statestr, sigstr);
 370                 else
 371                         strcpy(statestr, "Unknown signal");
 372                 if (WCOREDUMP(ps->status))
 373                         strcat(statestr, " (core dumped)");
 374         }
 375
 376         for (ps = jp->ps ; ; ps++) {    /* for each process */
 377                 if (mode == SHOWJOBS_PIDS || mode == SHOWJOBS_PGIDS) {
 378                         out1fmt("%d\n", (int)ps->pid);
 379                         goto skip;
 380                 }
 381                 if (mode != SHOWJOBS_VERBOSE && ps != jp->ps)
 382                         goto skip;
 383                 if (jobno == curr && ps == jp->ps)
 384                         c = '+';
 385                 else if (jobno == prev && ps == jp->ps)
 386                         c = '-';
 387                 else
 388                         c = ' ';
 389                 if (ps == jp->ps)
 390                         fmtstr(s, 64, "[%d] %c ", jobno, c);
 391                 else
 392                         fmtstr(s, 64, "    %c ", c);
 393                 out1str(s);
 394                 col = strlen(s);
 395                 if (mode == SHOWJOBS_VERBOSE) {
 396                         fmtstr(s, 64, "%d ", (int)ps->pid);
 397                         out1str(s);
 398                         col += strlen(s);
 399                 }
 400                 if (ps == jp->ps) {
 401                         out1str(statestr);
 402                         col += strlen(statestr);
 403                 }
 404                 do {
 405                         out1c(' ');
 406                         col++;
 407                 } while (col < 30);
 408                 if (mode == SHOWJOBS_VERBOSE) {
 409                         out1str(ps->cmd);
 410                         out1c('\n');
 411                 } else
 412                         printjobcmd(jp);
 413 skip:           if (--procno <= 0)
 414                         break;
 415         }
 416 }
 417
 418 /*
 419  * Print a list of jobs.  If "change" is nonzero, only print jobs whose
 420  * statuses have changed since the last call to showjobs.
 421  *
 422  * If the shell is interrupted in the process of creating a job, the
 423  * result may be a job structure containing zero processes.  Such structures
 424  * will be freed here.
 425  */
 426
 427 void
 428 showjobs(int change, int mode)
 429 {
 430         int jobno;
 431         struct job *jp;
 432
 433         TRACE(("showjobs(%d) called\n", change));
 434         checkzombies();
 435         for (jobno = 1, jp = jobtab ; jobno <= njobs ; jobno++, jp++) {
 436                 if (! jp->used)
 437                         continue;
 438                 if (jp->nprocs == 0) {
 439                         freejob(jp);
 440                         continue;
 441                 }
 442                 if (change && ! jp->changed)
 443                         continue;
 444                 showjob(jp, mode);
 445                 if (mode == SHOWJOBS_DEFAULT || mode == SHOWJOBS_VERBOSE) {
 446                         jp->changed = 0;
 447                         /* Hack: discard jobs for which $! has not been
 448                          * referenced in interactive mode when they terminate.
 449                          */
 450                         if (jp->state == JOBDONE && !jp->remembered &&
 451                                         (iflag || jp != bgjob)) {
 452                                 freejob(jp);
 453                         }
 454                 }
 455         }
 456 }
 457
 458
 459 /*
 460  * Mark a job structure as unused.
 461  */
 462
 463 static void
 464 freejob(struct job *jp)
 465 {
 466         struct procstat *ps;
 467         int i;
 468
 469         INTOFF;
 470         if (bgjob == jp)
 471                 bgjob = NULL;
 472         for (i = jp->nprocs, ps = jp->ps ; --i >= 0 ; ps++) {
 473                 if (ps->cmd != nullstr)
 474                         ckfree(ps->cmd);
 475         }
 476         if (jp->ps != &jp->ps0)
 477                 ckfree(jp->ps);
 478         jp->used = 0;
 479 #if JOBS
 480         deljob(jp);
 481 #endif
 482         INTON;
 483 }
 484
 485
 486
 487 int
 488 waitcmd(int argc __unused, char **argv __unused)
 489 {
 490         struct job *job;
 491         int retval;
 492
 493         nextopt("");
 494         if (*argptr == NULL)
 495                 return (waitcmdloop(NULL));
 496
 497         do {
 498                 job = getjob_nonotfound(*argptr);
 499                 if (job == NULL)
 500                         retval = 127;
 501                 else
 502                         retval = waitcmdloop(job);
 503                 argptr++;
 504         } while (*argptr != NULL);
 505
 506         return (retval);
 507 }
 508
 509 static int
 510 waitcmdloop(struct job *job)
 511 {
 512         int status, retval, sig;
 513         struct job *jp;
 514
 515         /*
 516          * Loop until a process is terminated or stopped, or a SIGINT is
 517          * received.
 518          */
 519
 520         do {
 521                 if (job != NULL) {
 522                         if (job->state == JOBDONE) {
 523                                 status = job->ps[job->nprocs - 1].status;
 524                                 if (WIFEXITED(status))
 525                                         retval = WEXITSTATUS(status);
 526                                 else
 527                                         retval = WTERMSIG(status) + 128;
 528                                 if (! iflag || ! job->changed)
 529                                         freejob(job);
 530                                 else {
 531                                         job->remembered = 0;
 532                                         if (job == bgjob)
 533                                                 bgjob = NULL;
 534                                 }
 535                                 return retval;
 536                         }
 537                 } else {
 538                         for (jp = jobtab ; jp < jobtab + njobs; jp++)
 539                                 if (jp->used && jp->state == JOBDONE) {
 540                                         if (! iflag || ! jp->changed)
 541                                                 freejob(jp);
 542                                         else {
 543                                                 jp->remembered = 0;
 544                                                 if (jp == bgjob)
 545                                                         bgjob = NULL;
 546                                         }
 547                                 }
 548                         for (jp = jobtab ; ; jp++) {
 549                                 if (jp >= jobtab + njobs) {     /* no running procs */
 550                                         return 0;
 551                                 }
 552                                 if (jp->used && jp->state == 0)
 553                                         break;
 554                         }
 555                 }
 556         } while (dowait(DOWAIT_BLOCK | DOWAIT_SIG, (struct job *)NULL) != -1);
 557
 558         sig = pendingsig_waitcmd;
 559         pendingsig_waitcmd = 0;
 560         return sig + 128;
 561 }
 562
 563
 564
 565 int
 566 jobidcmd(int argc __unused, char **argv __unused)
 567 {
 568         struct job *jp;
 569         int i;
 570
 571         nextopt("");
 572         jp = getjob(*argptr);
 573         for (i = 0 ; i < jp->nprocs ; ) {
 574                 out1fmt("%d", (int)jp->ps[i].pid);
 575                 out1c(++i < jp->nprocs? ' ' : '\n');
 576         }
 577         return 0;
 578 }
 579
 580
 581
 582 /*
 583  * Convert a job name to a job structure.
 584  */
 585
 586 static struct job *
 587 getjob_nonotfound(const char *name)
 588 {
 589         int jobno;
 590         struct job *found, *jp;
 591         size_t namelen;
 592         pid_t pid;
 593         int i;
 594
 595         if (name == NULL) {
 596 #if JOBS
 597 currentjob:     if ((jp = getcurjob(NULL)) == NULL)
 598                         error("No current job");
 599                 return (jp);
 600 #else
 601                 error("No current job");
 602 #endif
 603         } else if (name[0] == '%') {
 604                 if (is_digit(name[1])) {
 605                         jobno = number(name + 1);
 606                         if (jobno > 0 && jobno <= njobs
 607                          && jobtab[jobno - 1].used != 0)
 608                                 return &jobtab[jobno - 1];
 609 #if JOBS
 610                 } else if (name[1] == '%' && name[2] == '\0') {
 611                         goto currentjob;
 612                 } else if (name[1] == '+' && name[2] == '\0') {
 613                         goto currentjob;
 614                 } else if (name[1] == '-' && name[2] == '\0') {
 615                         if ((jp = getcurjob(NULL)) == NULL ||
 616                             (jp = getcurjob(jp)) == NULL)
 617                                 error("No previous job");
 618                         return (jp);
 619 #endif
 620                 } else if (name[1] == '?') {
 621                         found = NULL;
 622                         for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
 623                                 if (jp->used && jp->nprocs > 0
 624                                  && strstr(jp->ps[0].cmd, name + 2) != NULL) {
 625                                         if (found)
 626                                                 error("%s: ambiguous", name);
 627                                         found = jp;
 628                                 }
 629                         }
 630                         if (found != NULL)
 631                                 return (found);
 632                 } else {
 633                         namelen = strlen(name);
 634                         found = NULL;
 635                         for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
 636                                 if (jp->used && jp->nprocs > 0
 637                                  && strncmp(jp->ps[0].cmd, name + 1,
 638                                  namelen - 1) == 0) {
 639                                         if (found)
 640                                                 error("%s: ambiguous", name);
 641                                         found = jp;
 642                                 }
 643                         }
 644                         if (found)
 645                                 return found;
 646                 }
 647         } else if (is_number(name)) {
 648                 pid = (pid_t)number(name);
 649                 for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
 650                         if (jp->used && jp->nprocs > 0
 651                          && jp->ps[jp->nprocs - 1].pid == pid)
 652                                 return jp;
 653                 }
 654         }
 655         return NULL;
 656 }
 657
 658
 659 static struct job *
 660 getjob(const char *name)
 661 {
 662         struct job *jp;
 663
 664         jp = getjob_nonotfound(name);
 665         if (jp == NULL)
 666                 error("No such job: %s", name);
 667         return (jp);
 668 }
 669
 670
 671 int
 672 killjob(const char *name, int sig)
 673 {
 674         struct job *jp;
 675         int i, ret;
 676
 677         jp = getjob(name);
 678         if (jp->state == JOBDONE)
 679                 return 0;
 680         if (jp->jobctl)
 681                 return kill(-jp->ps[0].pid, sig);
 682         ret = -1;
 683         errno = ESRCH;
 684         for (i = 0; i < jp->nprocs; i++)
 685                 if (jp->ps[i].status == -1 || WIFSTOPPED(jp->ps[i].status)) {
 686                         if (kill(jp->ps[i].pid, sig) == 0)
 687                                 ret = 0;
 688                 } else
 689                         ret = 0;
 690         return ret;
 691 }
 692
 693 /*
 694  * Return a new job structure,
 695  */
 696
 697 struct job *
 698 makejob(union node *node __unused, int nprocs)
 699 {
 700         int i;
 701         struct job *jp;
 702
 703         for (i = njobs, jp = jobtab ; ; jp++) {
 704                 if (--i < 0) {
 705                         INTOFF;
 706                         if (njobs == 0) {
 707                                 jobtab = ckmalloc(4 * sizeof jobtab[0]);
 708 #if JOBS
 709                                 jobmru = NULL;
 710 #endif
 711                         } else {
 712                                 jp = ckmalloc((njobs + 4) * sizeof jobtab[0]);
 713                                 memcpy(jp, jobtab, njobs * sizeof jp[0]);
 714 #if JOBS
 715                                 /* Relocate `next' pointers and list head */
 716                                 if (jobmru != NULL)
 717                                         jobmru = &jp[jobmru - jobtab];
 718                                 for (i = 0; i < njobs; i++)
 719                                         if (jp[i].next != NULL)
 720                                                 jp[i].next = &jp[jp[i].next -
 721                                                     jobtab];
 722 #endif
 723                                 if (bgjob != NULL)
 724                                         bgjob = &jp[bgjob - jobtab];
 725                                 /* Relocate `ps' pointers */
 726                                 for (i = 0; i < njobs; i++)
 727                                         if (jp[i].ps == &jobtab[i].ps0)
 728                                                 jp[i].ps = &jp[i].ps0;
 729                                 ckfree(jobtab);
 730                                 jobtab = jp;
 731                         }
 732                         jp = jobtab + njobs;
 733                         for (i = 4 ; --i >= 0 ; jobtab[njobs++].used = 0)
 734                                 ;
 735                         INTON;
 736                         break;
 737                 }
 738                 if (jp->used == 0)
 739                         break;
 740         }
 741         INTOFF;
 742         jp->state = 0;
 743         jp->used = 1;
 744         jp->changed = 0;
 745         jp->nprocs = 0;
 746         jp->foreground = 0;
 747         jp->remembered = 0;
 748 #if JOBS
 749         jp->jobctl = jobctl;
 750         jp->next = NULL;
 751 #endif
 752         if (nprocs > 1) {
 753                 jp->ps = ckmalloc(nprocs * sizeof (struct procstat));
 754         } else {
 755                 jp->ps = &jp->ps0;
 756         }
 757         INTON;
 758         TRACE(("makejob(%p, %d) returns %%%td\n", (void *)node, nprocs,
 759             jp - jobtab + 1));
 760         return jp;
 761 }
 762
 763 #if JOBS
 764 static void
 765 setcurjob(struct job *cj)
 766 {
 767         struct job *jp, *prev;
 768
 769         for (prev = NULL, jp = jobmru; jp != NULL; prev = jp, jp = jp->next) {
 770                 if (jp == cj) {
 771                         if (prev != NULL)
 772                                 prev->next = jp->next;
 773                         else
 774                                 jobmru = jp->next;
 775                         jp->next = jobmru;
 776                         jobmru = cj;
 777                         return;
 778                 }
 779         }
 780         cj->next = jobmru;
 781         jobmru = cj;
 782 }
 783
 784 static void
 785 deljob(struct job *j)
 786 {
 787         struct job *jp, *prev;
 788
 789         for (prev = NULL, jp = jobmru; jp != NULL; prev = jp, jp = jp->next) {
 790                 if (jp == j) {
 791                         if (prev != NULL)
 792                                 prev->next = jp->next;
 793                         else
 794                                 jobmru = jp->next;
 795                         return;
 796                 }
 797         }
 798 }
 799
 800 /*
 801  * Return the most recently used job that isn't `nj', and preferably one
 802  * that is stopped.
 803  */
 804 static struct job *
 805 getcurjob(struct job *nj)
 806 {
 807         struct job *jp;
 808
 809         /* Try to find a stopped one.. */
 810         for (jp = jobmru; jp != NULL; jp = jp->next)
 811                 if (jp->used && jp != nj && jp->state == JOBSTOPPED)
 812                         return (jp);
 813         /* Otherwise the most recently used job that isn't `nj' */
 814         for (jp = jobmru; jp != NULL; jp = jp->next)
 815                 if (jp->used && jp != nj)
 816                         return (jp);
 817
 818         return (NULL);
 819 }
 820
 821 #endif
 822
 823 /*
 824  * Fork of a subshell.  If we are doing job control, give the subshell its
 825  * own process group.  Jp is a job structure that the job is to be added to.
 826  * N is the command that will be evaluated by the child.  Both jp and n may
 827  * be NULL.  The mode parameter can be one of the following:
 828  *      FORK_FG - Fork off a foreground process.
 829  *      FORK_BG - Fork off a background process.
 830  *      FORK_NOJOB - Like FORK_FG, but don't give the process its own
 831  *                   process group even if job control is on.
 832  *
 833  * When job control is turned off, background processes have their standard
 834  * input redirected to /dev/null (except for the second and later processes
 835  * in a pipeline).
 836  */
 837
 838 pid_t
 839 forkshell(struct job *jp, union node *n, int mode)
 840 {
 841         pid_t pid;
 842         pid_t pgrp;
 843
 844         TRACE(("forkshell(%%%td, %p, %d) called\n", jp - jobtab, (void *)n,
 845             mode));
 846         INTOFF;
 847         if (mode == FORK_BG && (jp == NULL || jp->nprocs == 0))
 848                 checkzombies();
 849         flushall();
 850         pid = fork();
 851         if (pid == -1) {
 852                 TRACE(("Fork failed, errno=%d\n", errno));
 853                 INTON;
 854                 error("Cannot fork: %s", strerror(errno));
 855         }
 856         if (pid == 0) {
 857                 struct job *p;
 858                 int wasroot;
 859                 int i;
 860
 861                 TRACE(("Child shell %d\n", (int)getpid()));
 862                 wasroot = rootshell;
 863                 rootshell = 0;
 864                 handler = &main_handler;
 865                 closescript();
 866                 INTON;
 867                 forcelocal = 0;
 868                 clear_traps();
 869 #if JOBS
 870                 jobctl = 0;             /* do job control only in root shell */
 871                 if (wasroot && mode != FORK_NOJOB && mflag) {
 872                         if (jp == NULL || jp->nprocs == 0)
 873                                 pgrp = getpid();
 874                         else
 875                                 pgrp = jp->ps[0].pid;
 876                         if (setpgid(0, pgrp) == 0 && mode == FORK_FG &&
 877                             ttyfd >= 0) {
 878                                 /*** this causes superfluous TIOCSPGRPS ***/
 879                                 if (tcsetpgrp(ttyfd, pgrp) < 0)
 880                                         error("tcsetpgrp failed, errno=%d", errno);
 881                         }
 882                         setsignal(SIGTSTP);
 883                         setsignal(SIGTTOU);
 884                 } else if (mode == FORK_BG) {
 885                         ignoresig(SIGINT);
 886                         ignoresig(SIGQUIT);
 887                         if ((jp == NULL || jp->nprocs == 0) &&
 888                             ! fd0_redirected_p ()) {
 889                                 close(0);
 890                                 if (open(_PATH_DEVNULL, O_RDONLY) != 0)
 891                                         error("cannot open %s: %s",
 892                                             _PATH_DEVNULL, strerror(errno));
 893                         }
 894                 }
 895 #else
 896                 if (mode == FORK_BG) {
 897                         ignoresig(SIGINT);
 898                         ignoresig(SIGQUIT);
 899                         if ((jp == NULL || jp->nprocs == 0) &&
 900                             ! fd0_redirected_p ()) {
 901                                 close(0);
 902                                 if (open(_PATH_DEVNULL, O_RDONLY) != 0)
 903                                         error("cannot open %s: %s",
 904                                             _PATH_DEVNULL, strerror(errno));
 905                         }
 906                 }
 907 #endif
 908                 INTOFF;
 909                 for (i = njobs, p = jobtab ; --i >= 0 ; p++)
 910                         if (p->used)
 911                                 freejob(p);
 912                 INTON;
 913                 if (wasroot && iflag) {
 914                         setsignal(SIGINT);
 915                         setsignal(SIGQUIT);
 916                         setsignal(SIGTERM);
 917                 }
 918                 return pid;
 919         }
 920         if (rootshell && mode != FORK_NOJOB && mflag) {
 921                 if (jp == NULL || jp->nprocs == 0)
 922                         pgrp = pid;
 923                 else
 924                         pgrp = jp->ps[0].pid;
 925                 setpgid(pid, pgrp);
 926         }
 927         if (mode == FORK_BG) {
 928                 if (bgjob != NULL && bgjob->state == JOBDONE &&
 929                     !bgjob->remembered && !iflag)
 930                         freejob(bgjob);
 931                 backgndpid = pid;               /* set $! */
 932                 bgjob = jp;
 933         }
 934         if (jp) {
 935                 struct procstat *ps = &jp->ps[jp->nprocs++];
 936                 ps->pid = pid;
 937                 ps->status = -1;
 938                 ps->cmd = nullstr;
 939                 if (iflag && rootshell && n)
 940                         ps->cmd = commandtext(n);
 941                 jp->foreground = mode == FORK_FG;
 942 #if JOBS
 943                 setcurjob(jp);
 944 #endif
 945         }
 946         INTON;
 947         TRACE(("In parent shell:  child = %d\n", (int)pid));
 948         return pid;
 949 }
 950
 951
 952 pid_t
 953 vforkexecshell(struct job *jp, char **argv, char **envp, const char *path, int idx, int pip[2])
 954 {
 955         pid_t pid;
 956         struct jmploc jmploc;
 957         struct jmploc *savehandler;
 958
 959         TRACE(("vforkexecshell(%%%td, %s, %p) called\n", jp - jobtab, argv[0],
 960             (void *)pip));
 961         INTOFF;
 962         flushall();
 963         savehandler = handler;
 964         pid = vfork();
 965         if (pid == -1) {
 966                 TRACE(("Vfork failed, errno=%d\n", errno));
 967                 INTON;
 968                 error("Cannot fork: %s", strerror(errno));
 969         }
 970         if (pid == 0) {
 971                 TRACE(("Child shell %d\n", (int)getpid()));
 972                 if (setjmp(jmploc.loc))
 973                         _exit(exception == EXEXEC ? exerrno : 2);
 974                 if (pip != NULL) {
 975                         close(pip[0]);
 976                         if (pip[1] != 1) {
 977                                 dup2(pip[1], 1);
 978                                 close(pip[1]);
 979                         }
 980                 }
 981                 handler = &jmploc;
 982                 shellexec(argv, envp, path, idx);
 983         }
 984         handler = savehandler;
 985         if (jp) {
 986                 struct procstat *ps = &jp->ps[jp->nprocs++];
 987                 ps->pid = pid;
 988                 ps->status = -1;
 989                 ps->cmd = nullstr;
 990                 jp->foreground = 1;
 991 #if JOBS
 992                 setcurjob(jp);
 993 #endif
 994         }
 995         INTON;
 996         TRACE(("In parent shell:  child = %d\n", (int)pid));
 997         return pid;
 998 }
 999
1000
1001 /*
1002  * Wait for job to finish.
1003  *
1004  * Under job control we have the problem that while a child process is
1005  * running interrupts generated by the user are sent to the child but not
1006  * to the shell.  This means that an infinite loop started by an inter-
1007  * active user may be hard to kill.  With job control turned off, an
1008  * interactive user may place an interactive program inside a loop.  If
1009  * the interactive program catches interrupts, the user doesn't want
1010  * these interrupts to also abort the loop.  The approach we take here
1011  * is to have the shell ignore interrupt signals while waiting for a
1012  * foreground process to terminate, and then send itself an interrupt
1013  * signal if the child process was terminated by an interrupt signal.
1014  * Unfortunately, some programs want to do a bit of cleanup and then
1015  * exit on interrupt; unless these processes terminate themselves by
1016  * sending a signal to themselves (instead of calling exit) they will
1017  * confuse this approach.
1018  */
1019
1020 int
1021 waitforjob(struct job *jp, int *origstatus)
1022 {
1023 #if JOBS
1024         int propagate_int = jp->jobctl && jp->foreground;
1025 #endif
1026         int status;
1027         int st;
1028
1029         INTOFF;
1030         TRACE(("waitforjob(%%%td) called\n", jp - jobtab + 1));
1031         while (jp->state == 0)
1032                 if (dowait(DOWAIT_BLOCK | (Tflag ? DOWAIT_SIG |
1033                     DOWAIT_SIG_ANY : 0), jp) == -1)
1034                         dotrap();
1035 #if JOBS
1036         if (jp->jobctl) {
1037                 if (ttyfd >= 0 && tcsetpgrp(ttyfd, rootpid) < 0)
1038                         error("tcsetpgrp failed, errno=%d\n", errno);
1039         }
1040         if (jp->state == JOBSTOPPED)
1041                 setcurjob(jp);
1042 #endif
1043         status = jp->ps[jp->nprocs - 1].status;
1044         if (origstatus != NULL)
1045                 *origstatus = status;
1046         /* convert to 8 bits */
1047         if (WIFEXITED(status))
1048                 st = WEXITSTATUS(status);
1049 #if JOBS
1050         else if (WIFSTOPPED(status))
1051                 st = WSTOPSIG(status) + 128;
1052 #endif
1053         else
1054                 st = WTERMSIG(status) + 128;
1055         if (! JOBS || jp->state == JOBDONE)
1056                 freejob(jp);
1057         if (int_pending()) {
1058                 if (!WIFSIGNALED(status) || WTERMSIG(status) != SIGINT)
1059                         CLEAR_PENDING_INT;
1060         }
1061 #if JOBS
1062         else if (rootshell && iflag && propagate_int &&
1063                         WIFSIGNALED(status) && WTERMSIG(status) == SIGINT)
1064                 kill(getpid(), SIGINT);
1065 #endif
1066         INTON;
1067         return st;
1068 }
1069
1070
1071 static void
1072 dummy_handler(int sig __unused)
1073 {
1074 }
1075
1076 /*
1077  * Wait for a process to terminate.
1078  */
1079
1080 static pid_t
1081 dowait(int mode, struct job *job)
1082 {
1083         struct sigaction sa, osa;
1084         sigset_t mask, omask;
1085         pid_t pid;
1086         int status;
1087         struct procstat *sp;
1088         struct job *jp;
1089         struct job *thisjob;
1090         const char *sigstr;
1091         int done;
1092         int stopped;
1093         int sig;
1094         int coredump;
1095         int wflags;
1096         int restore_sigchld;
1097
1098         TRACE(("dowait(%d, %p) called\n", mode, job));
1099         restore_sigchld = 0;
1100         if ((mode & DOWAIT_SIG) != 0) {
1101                 sigfillset(&mask);
1102                 sigprocmask(SIG_BLOCK, &mask, &omask);
1103                 INTOFF;
1104                 if (!issigchldtrapped()) {
1105                         restore_sigchld = 1;
1106                         sa.sa_handler = dummy_handler;
1107                         sa.sa_flags = 0;
1108                         sigemptyset(&sa.sa_mask);
1109                         sigaction(SIGCHLD, &sa, &osa);
1110                 }
1111         }
1112         do {
1113 #if JOBS
1114                 if (iflag)
1115                         wflags = WUNTRACED | WCONTINUED;
1116                 else
1117 #endif
1118                         wflags = 0;
1119                 if ((mode & (DOWAIT_BLOCK | DOWAIT_SIG)) != DOWAIT_BLOCK)
1120                         wflags |= WNOHANG;
1121                 pid = wait3(&status, wflags, (struct rusage *)NULL);
1122                 TRACE(("wait returns %d, status=%d\n", (int)pid, status));
1123                 if (pid == 0 && (mode & DOWAIT_SIG) != 0) {
1124                         pid = -1;
1125                         if (((mode & DOWAIT_SIG_ANY) != 0 ?
1126                             pendingsig : pendingsig_waitcmd) != 0) {
1127                                 errno = EINTR;
1128                                 break;
1129                         }
1130                         sigsuspend(&omask);
1131                         if (int_pending())
1132                                 break;
1133                 }
1134         } while (pid == -1 && errno == EINTR);
1135         if (pid == -1 && errno == ECHILD && job != NULL)
1136                 job->state = JOBDONE;
1137         if ((mode & DOWAIT_SIG) != 0) {
1138                 if (restore_sigchld)
1139                         sigaction(SIGCHLD, &osa, NULL);
1140                 sigprocmask(SIG_SETMASK, &omask, NULL);
1141                 INTON;
1142         }
1143         if (pid <= 0)
1144                 return pid;
1145         INTOFF;
1146         thisjob = NULL;
1147         for (jp = jobtab ; jp < jobtab + njobs ; jp++) {
1148                 if (jp->used && jp->nprocs > 0) {
1149                         done = 1;
1150                         stopped = 1;
1151                         for (sp = jp->ps ; sp < jp->ps + jp->nprocs ; sp++) {
1152                                 if (sp->pid == -1)
1153                                         continue;
1154                                 if (sp->pid == pid && (sp->status == -1 ||
1155                                     WIFSTOPPED(sp->status))) {
1156                                         TRACE(("Changing status of proc %d from 0x%x to 0x%x\n",
1157                                                    (int)pid, sp->status,
1158                                                    status));
1159                                         if (WIFCONTINUED(status)) {
1160                                                 sp->status = -1;
1161                                                 jp->state = 0;
1162                                         } else
1163                                                 sp->status = status;
1164                                         thisjob = jp;
1165                                 }
1166                                 if (sp->status == -1)
1167                                         stopped = 0;
1168                                 else if (WIFSTOPPED(sp->status))
1169                                         done = 0;
1170                         }
1171                         if (stopped) {          /* stopped or done */
1172                                 int state = done? JOBDONE : JOBSTOPPED;
1173                                 if (jp->state != state) {
1174                                         TRACE(("Job %td: changing state from %d to %d\n", jp - jobtab + 1, jp->state, state));
1175                                         jp->state = state;
1176                                         if (jp != job) {
1177                                                 if (done && !jp->remembered &&
1178                                                     !iflag && jp != bgjob)
1179                                                         freejob(jp);
1180 #if JOBS
1181                                                 else if (done)
1182                                                         deljob(jp);
1183 #endif
1184                                         }
1185                                 }
1186                         }
1187                 }
1188         }
1189         INTON;
1190         if (!thisjob || thisjob->state == 0)
1191                 ;
1192         else if ((!rootshell || !iflag || thisjob == job) &&
1193             thisjob->foreground && thisjob->state != JOBSTOPPED) {
1194                 sig = 0;
1195                 coredump = 0;
1196                 for (sp = thisjob->ps; sp < thisjob->ps + thisjob->nprocs; sp++)
1197                         if (WIFSIGNALED(sp->status)) {
1198                                 sig = WTERMSIG(sp->status);
1199                                 coredump = WCOREDUMP(sp->status);
1200                         }
1201                 if (sig > 0 && sig != SIGINT && sig != SIGPIPE) {
1202                         sigstr = strsignal(sig);
1203                         if (sigstr != NULL)
1204                                 out2str(sigstr);
1205                         else
1206                                 out2str("Unknown signal");
1207                         if (coredump)
1208                                 out2str(" (core dumped)");
1209                         out2c('\n');
1210                         flushout(out2);
1211                 }
1212         } else {
1213                 TRACE(("Not printing status, rootshell=%d, job=%p\n", rootshell, job));
1214                 thisjob->changed = 1;
1215         }
1216         return pid;
1217 }
1218
1219
1220
1221 /*
1222  * return 1 if there are stopped jobs, otherwise 0
1223  */
1224 int job_warning = 0;
1225 int
1226 stoppedjobs(void)
1227 {
1228         int jobno;
1229         struct job *jp;
1230
1231         if (job_warning)
1232                 return (0);
1233         for (jobno = 1, jp = jobtab; jobno <= njobs; jobno++, jp++) {
1234                 if (jp->used == 0)
1235                         continue;
1236                 if (jp->state == JOBSTOPPED) {
1237                         out2fmt_flush("You have stopped jobs.\n");
1238                         job_warning = 2;
1239                         return (1);
1240                 }
1241         }
1242
1243         return (0);
1244 }
1245
1246
1247 static void
1248 checkzombies(void)
1249 {
1250         while (njobs > 0 && dowait(0, NULL) > 0)
1251                 ;
1252 }
1253
1254
1255 int
1256 backgndpidset(void)
1257 {
1258         return backgndpid != -1;
1259 }
1260
1261
1262 pid_t
1263 backgndpidval(void)
1264 {
1265         if (bgjob != NULL && !forcelocal)
1266                 bgjob->remembered = 1;
1267         return backgndpid;
1268 }
1269
1270 /*
1271  * Return a string identifying a command (to be printed by the
1272  * jobs command.
1273  */
1274
1275 static char *cmdnextc;
1276 static int cmdnleft;
1277 #define MAXCMDTEXT      200
1278
1279 char *
1280 commandtext(union node *n)
1281 {
1282         char *name;
1283
1284         cmdnextc = name = ckmalloc(MAXCMDTEXT);
1285         cmdnleft = MAXCMDTEXT - 4;
1286         cmdtxt(n);
1287         *cmdnextc = '\0';
1288         return name;
1289 }
1290
1291
1292 static void
1293 cmdtxt(union node *n)
1294 {
1295         union node *np;
1296         struct nodelist *lp;
1297         const char *p;
1298         int i;
1299         char s[2];
1300
1301         if (n == NULL)
1302                 return;
1303         switch (n->type) {
1304         case NSEMI:
1305                 cmdtxt(n->nbinary.ch1);
1306                 cmdputs("; ");
1307                 cmdtxt(n->nbinary.ch2);
1308                 break;
1309         case NAND:
1310                 cmdtxt(n->nbinary.ch1);
1311                 cmdputs(" && ");
1312                 cmdtxt(n->nbinary.ch2);
1313                 break;
1314         case NOR:
1315                 cmdtxt(n->nbinary.ch1);
1316                 cmdputs(" || ");
1317                 cmdtxt(n->nbinary.ch2);
1318                 break;
1319         case NPIPE:
1320                 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) {
1321                         cmdtxt(lp->n);
1322                         if (lp->next)
1323                                 cmdputs(" | ");
1324                 }
1325                 break;
1326         case NSUBSHELL:
1327                 cmdputs("(");
1328                 cmdtxt(n->nredir.n);
1329                 cmdputs(")");
1330                 break;
1331         case NREDIR:
1332         case NBACKGND:
1333                 cmdtxt(n->nredir.n);
1334                 break;
1335         case NIF:
1336                 cmdputs("if ");
1337                 cmdtxt(n->nif.test);
1338                 cmdputs("; then ");
1339                 cmdtxt(n->nif.ifpart);
1340                 cmdputs("...");
1341                 break;
1342         case NWHILE:
1343                 cmdputs("while ");
1344                 goto until;
1345         case NUNTIL:
1346                 cmdputs("until ");
1347 until:
1348                 cmdtxt(n->nbinary.ch1);
1349                 cmdputs("; do ");
1350                 cmdtxt(n->nbinary.ch2);
1351                 cmdputs("; done");
1352                 break;
1353         case NFOR:
1354                 cmdputs("for ");
1355                 cmdputs(n->nfor.var);
1356                 cmdputs(" in ...");
1357                 break;
1358         case NCASE:
1359                 cmdputs("case ");
1360                 cmdputs(n->ncase.expr->narg.text);
1361                 cmdputs(" in ...");
1362                 break;
1363         case NDEFUN:
1364                 cmdputs(n->narg.text);
1365                 cmdputs("() ...");
1366                 break;
1367         case NNOT:
1368                 cmdputs("! ");
1369                 cmdtxt(n->nnot.com);
1370                 break;
1371         case NCMD:
1372                 for (np = n->ncmd.args ; np ; np = np->narg.next) {
1373                         cmdtxt(np);
1374                         if (np->narg.next)
1375                                 cmdputs(" ");
1376                 }
1377                 for (np = n->ncmd.redirect ; np ; np = np->nfile.next) {
1378                         cmdputs(" ");
1379                         cmdtxt(np);
1380                 }
1381                 break;
1382         case NARG:
1383                 cmdputs(n->narg.text);
1384                 break;
1385         case NTO:
1386                 p = ">";  i = 1;  goto redir;
1387         case NAPPEND:
1388                 p = ">>";  i = 1;  goto redir;
1389         case NTOFD:
1390                 p = ">&";  i = 1;  goto redir;
1391         case NCLOBBER:
1392                 p = ">|"; i = 1; goto redir;
1393         case NFROM:
1394                 p = "<";  i = 0;  goto redir;
1395         case NFROMTO:
1396                 p = "<>";  i = 0;  goto redir;
1397         case NFROMFD:
1398                 p = "<&";  i = 0;  goto redir;
1399 redir:
1400                 if (n->nfile.fd != i) {
1401                         s[0] = n->nfile.fd + '0';
1402                         s[1] = '\0';
1403                         cmdputs(s);
1404                 }
1405                 cmdputs(p);
1406                 if (n->type == NTOFD || n->type == NFROMFD) {
1407                         if (n->ndup.dupfd >= 0)
1408                                 s[0] = n->ndup.dupfd + '0';
1409                         else
1410                                 s[0] = '-';
1411                         s[1] = '\0';
1412                         cmdputs(s);
1413                 } else {
1414                         cmdtxt(n->nfile.fname);
1415                 }
1416                 break;
1417         case NHERE:
1418         case NXHERE:
1419                 cmdputs("<<...");
1420                 break;
1421         default:
1422                 cmdputs("???");
1423                 break;
1424         }
1425 }
1426
1427
1428
1429 static void
1430 cmdputs(const char *s)
1431 {
1432         const char *p;
1433         char *q;
1434         char c;
1435         int subtype = 0;
1436
1437         if (cmdnleft <= 0)
1438                 return;
1439         p = s;
1440         q = cmdnextc;
1441         while ((c = *p++) != '\0') {
1442                 if (c == CTLESC)
1443                         *q++ = *p++;
1444                 else if (c == CTLVAR) {
1445                         *q++ = '$';
1446                         if (--cmdnleft > 0)
1447                                 *q++ = '{';
1448                         subtype = *p++;
1449                         if ((subtype & VSTYPE) == VSLENGTH && --cmdnleft > 0)
1450                                 *q++ = '#';
1451                 } else if (c == '=' && subtype != 0) {
1452                         *q = "}-+?=##%%\0X"[(subtype & VSTYPE) - VSNORMAL];
1453                         if (*q)
1454                                 q++;
1455                         else
1456                                 cmdnleft++;
1457                         if (((subtype & VSTYPE) == VSTRIMLEFTMAX ||
1458                             (subtype & VSTYPE) == VSTRIMRIGHTMAX) &&
1459                             --cmdnleft > 0)
1460                                 *q = q[-1], q++;
1461                         subtype = 0;
1462                 } else if (c == CTLENDVAR) {
1463                         *q++ = '}';
1464                 } else if (c == CTLBACKQ || c == CTLBACKQ+CTLQUOTE) {
1465                         cmdnleft -= 5;
1466                         if (cmdnleft > 0) {
1467                                 *q++ = '$';
1468                                 *q++ = '(';
1469                                 *q++ = '.';
1470                                 *q++ = '.';
1471                                 *q++ = '.';
1472                                 *q++ = ')';
1473                         }
1474                 } else if (c == CTLARI) {
1475                         cmdnleft -= 2;
1476                         if (cmdnleft > 0) {
1477                                 *q++ = '$';
1478                                 *q++ = '(';
1479                                 *q++ = '(';
1480                         }
1481                         p++;
1482                 } else if (c == CTLENDARI) {
1483                         if (--cmdnleft > 0) {
1484                                 *q++ = ')';
1485                                 *q++ = ')';
1486                         }
1487                 } else if (c == CTLQUOTEMARK || c == CTLQUOTEEND)
1488                         cmdnleft++; /* ignore */
1489                 else
1490                         *q++ = c;
1491                 if (--cmdnleft <= 0) {
1492                         *q++ = '.';
1493                         *q++ = '.';
1494                         *q++ = '.';
1495                         break;
1496                 }
1497         }
1498         cmdnextc = q;
1499 }