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