bin/sh/jobs.c

   1 /*-
   2  * Copyright (c) 1991, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Kenneth Almquist.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. 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 #include "eval.h"
  77
  78
  79 /*
  80  * A job structure contains information about a job.  A job is either a
  81  * single process or a set of processes contained in a pipeline.  In the
  82  * latter case, pidlist will be non-NULL, and will point to a -1 terminated
  83  * array of pids.
  84  */
  85
  86 struct procstat {
  87         pid_t pid;              /* process id */
  88         int status;             /* status flags (defined above) */
  89         char *cmd;              /* text of command being run */
  90 };
  91
  92
  93 /* states */
  94 #define JOBSTOPPED 1            /* all procs are stopped */
  95 #define JOBDONE 2               /* all procs are completed */
  96
  97
  98 struct job {
  99         struct procstat ps0;    /* status of process */
 100         struct procstat *ps;    /* status or processes when more than one */
 101         short nprocs;           /* number of processes */
 102         pid_t pgrp;             /* process group of this job */
 103         char state;             /* true if job is finished */
 104         char used;              /* true if this entry is in used */
 105         char changed;           /* true if status has changed */
 106         char foreground;        /* true if running in the foreground */
 107         char remembered;        /* true if $! referenced */
 108         char pipefail;          /* pass any non-zero status */
 109 #if JOBS
 110         char jobctl;            /* job running under job control */
 111         struct job *next;       /* job used after this one */
 112 #endif
 113 };
 114
 115
 116 static struct job *jobtab;      /* array of jobs */
 117 static int njobs;               /* size of array */
 118 static pid_t backgndpid = -1;   /* pid of last background process */
 119 static struct job *bgjob = NULL; /* last background process */
 120 #if JOBS
 121 static struct job *jobmru;      /* most recently used job list */
 122 static pid_t initialpgrp;       /* pgrp of shell on invocation */
 123 #endif
 124 static int ttyfd = -1;
 125
 126 /* mode flags for dowait */
 127 #define DOWAIT_BLOCK    0x1 /* wait until a child exits */
 128 #define DOWAIT_SIG      0x2 /* if DOWAIT_BLOCK, abort on signal */
 129 #define DOWAIT_SIG_TRAP 0x4 /* if DOWAIT_SIG, abort on trapped signal only */
 130
 131 #if JOBS
 132 static void restartjob(struct job *);
 133 #endif
 134 static void freejob(struct job *);
 135 static int waitcmdloop(struct job *);
 136 static struct job *getjob_nonotfound(const char *);
 137 static struct job *getjob(const char *);
 138 pid_t killjob(const char *, int);
 139 static pid_t dowait(int, struct job *);
 140 static void checkzombies(void);
 141 static void cmdtxt(union node *);
 142 static void cmdputs(const char *);
 143 #if JOBS
 144 static void setcurjob(struct job *);
 145 static void deljob(struct job *);
 146 static struct job *getcurjob(struct job *);
 147 #endif
 148 static int getjobstatus(const struct job *);
 149 static void printjobcmd(struct job *);
 150 static void showjob(struct job *, int);
 151
 152
 153 /*
 154  * Turn job control on and off.
 155  */
 156
 157 static int jobctl;
 158
 159 #if JOBS
 160 static void
 161 jobctl_notty(void)
 162 {
 163         if (ttyfd >= 0) {
 164                 close(ttyfd);
 165                 ttyfd = -1;
 166         }
 167         if (!iflag) {
 168                 setsignal(SIGTSTP);
 169                 setsignal(SIGTTOU);
 170                 setsignal(SIGTTIN);
 171                 jobctl = 1;
 172                 return;
 173         }
 174         out2fmt_flush("sh: can't access tty; job control turned off\n");
 175         mflag = 0;
 176 }
 177
 178 void
 179 setjobctl(int on)
 180 {
 181         int i;
 182
 183         if (on == jobctl || rootshell == 0)
 184                 return;
 185         if (on) {
 186                 if (ttyfd != -1)
 187                         close(ttyfd);
 188                 if ((ttyfd = open(_PATH_TTY, O_RDWR | O_CLOEXEC)) < 0) {
 189                         i = 0;
 190                         while (i <= 2 && !isatty(i))
 191                                 i++;
 192                         if (i > 2 ||
 193                             (ttyfd = fcntl(i, F_DUPFD_CLOEXEC, 10)) < 0) {
 194                                 jobctl_notty();
 195                                 return;
 196                         }
 197                 }
 198                 if (ttyfd < 10) {
 199                         /*
 200                          * Keep our TTY file descriptor out of the way of
 201                          * the user's redirections.
 202                          */
 203                         if ((i = fcntl(ttyfd, F_DUPFD_CLOEXEC, 10)) < 0) {
 204                                 jobctl_notty();
 205                                 return;
 206                         }
 207                         close(ttyfd);
 208                         ttyfd = i;
 209                 }
 210                 do { /* while we are in the background */
 211                         initialpgrp = tcgetpgrp(ttyfd);
 212                         if (initialpgrp < 0) {
 213                                 jobctl_notty();
 214                                 return;
 215                         }
 216                         if (initialpgrp != getpgrp()) {
 217                                 if (!iflag) {
 218                                         initialpgrp = -1;
 219                                         jobctl_notty();
 220                                         return;
 221                                 }
 222                                 kill(0, SIGTTIN);
 223                                 continue;
 224                         }
 225                 } while (0);
 226                 setsignal(SIGTSTP);
 227                 setsignal(SIGTTOU);
 228                 setsignal(SIGTTIN);
 229                 setpgid(0, rootpid);
 230                 tcsetpgrp(ttyfd, rootpid);
 231         } else { /* turning job control off */
 232                 setpgid(0, initialpgrp);
 233                 if (ttyfd >= 0) {
 234                         tcsetpgrp(ttyfd, initialpgrp);
 235                         close(ttyfd);
 236                         ttyfd = -1;
 237                 }
 238                 setsignal(SIGTSTP);
 239                 setsignal(SIGTTOU);
 240                 setsignal(SIGTTIN);
 241         }
 242         jobctl = on;
 243 }
 244 #endif
 245
 246
 247 #if JOBS
 248 int
 249 fgcmd(int argc __unused, char **argv __unused)
 250 {
 251         struct job *jp;
 252         pid_t pgrp;
 253         int status;
 254
 255         nextopt("");
 256         jp = getjob(*argptr);
 257         if (jp->jobctl == 0)
 258                 error("job not created under job control");
 259         printjobcmd(jp);
 260         flushout(&output);
 261         pgrp = jp->ps[0].pid;
 262         if (ttyfd >= 0)
 263                 tcsetpgrp(ttyfd, pgrp);
 264         restartjob(jp);
 265         jp->foreground = 1;
 266         INTOFF;
 267         status = waitforjob(jp, (int *)NULL);
 268         INTON;
 269         return status;
 270 }
 271
 272
 273 int
 274 bgcmd(int argc __unused, char **argv __unused)
 275 {
 276         struct job *jp;
 277
 278         nextopt("");
 279         do {
 280                 jp = getjob(*argptr);
 281                 if (jp->jobctl == 0)
 282                         error("job not created under job control");
 283                 if (jp->state == JOBDONE)
 284                         continue;
 285                 restartjob(jp);
 286                 jp->foreground = 0;
 287                 out1fmt("[%td] ", jp - jobtab + 1);
 288                 printjobcmd(jp);
 289         } while (*argptr != NULL && *++argptr != NULL);
 290         return 0;
 291 }
 292
 293
 294 static void
 295 restartjob(struct job *jp)
 296 {
 297         struct procstat *ps;
 298         int i;
 299
 300         if (jp->state == JOBDONE)
 301                 return;
 302         setcurjob(jp);
 303         INTOFF;
 304         kill(-jp->ps[0].pid, SIGCONT);
 305         for (ps = jp->ps, i = jp->nprocs ; --i >= 0 ; ps++) {
 306                 if (WIFSTOPPED(ps->status)) {
 307                         ps->status = -1;
 308                         jp->state = 0;
 309                 }
 310         }
 311         INTON;
 312 }
 313 #endif
 314
 315
 316 int
 317 jobscmd(int argc __unused, char *argv[] __unused)
 318 {
 319         char *id;
 320         int ch, mode;
 321
 322         mode = SHOWJOBS_DEFAULT;
 323         while ((ch = nextopt("lps")) != '\0') {
 324                 switch (ch) {
 325                 case 'l':
 326                         mode = SHOWJOBS_VERBOSE;
 327                         break;
 328                 case 'p':
 329                         mode = SHOWJOBS_PGIDS;
 330                         break;
 331                 case 's':
 332                         mode = SHOWJOBS_PIDS;
 333                         break;
 334                 }
 335         }
 336
 337         if (*argptr == NULL)
 338                 showjobs(0, mode);
 339         else
 340                 while ((id = *argptr++) != NULL)
 341                         showjob(getjob(id), mode);
 342
 343         return (0);
 344 }
 345
 346 static int getjobstatus(const struct job *jp)
 347 {
 348         int i, status;
 349
 350         if (!jp->pipefail)
 351                 return (jp->ps[jp->nprocs - 1].status);
 352         for (i = jp->nprocs - 1; i >= 0; i--) {
 353                 status = jp->ps[i].status;
 354                 if (status != 0)
 355                         return (status);
 356         }
 357         return (0);
 358 }
 359
 360 static void
 361 printjobcmd(struct job *jp)
 362 {
 363         struct procstat *ps;
 364         int i;
 365
 366         for (ps = jp->ps, i = jp->nprocs ; --i >= 0 ; ps++) {
 367                 out1str(ps->cmd);
 368                 if (i > 0)
 369                         out1str(" | ");
 370         }
 371         out1c('\n');
 372 }
 373
 374 static void
 375 showjob(struct job *jp, int mode)
 376 {
 377         char s[64];
 378         char statebuf[16];
 379         const char *statestr, *coredump;
 380         struct procstat *ps;
 381         struct job *j;
 382         int col, curr, i, jobno, prev, procno, status;
 383         char c;
 384
 385         procno = (mode == SHOWJOBS_PGIDS) ? 1 : jp->nprocs;
 386         jobno = jp - jobtab + 1;
 387         curr = prev = 0;
 388 #if JOBS
 389         if ((j = getcurjob(NULL)) != NULL) {
 390                 curr = j - jobtab + 1;
 391                 if ((j = getcurjob(j)) != NULL)
 392                         prev = j - jobtab + 1;
 393         }
 394 #endif
 395         coredump = "";
 396         status = getjobstatus(jp);
 397         if (jp->state == 0) {
 398                 statestr = "Running";
 399 #if JOBS
 400         } else if (jp->state == JOBSTOPPED) {
 401                 ps = jp->ps + jp->nprocs - 1;
 402                 while (!WIFSTOPPED(ps->status) && ps > jp->ps)
 403                         ps--;
 404                 if (WIFSTOPPED(ps->status))
 405                         i = WSTOPSIG(ps->status);
 406                 else
 407                         i = -1;
 408                 statestr = strsignal(i);
 409                 if (statestr == NULL)
 410                         statestr = "Suspended";
 411 #endif
 412         } else if (WIFEXITED(status)) {
 413                 if (WEXITSTATUS(status) == 0)
 414                         statestr = "Done";
 415                 else {
 416                         fmtstr(statebuf, sizeof(statebuf), "Done(%d)",
 417                             WEXITSTATUS(status));
 418                         statestr = statebuf;
 419                 }
 420         } else {
 421                 i = WTERMSIG(status);
 422                 statestr = strsignal(i);
 423                 if (statestr == NULL)
 424                         statestr = "Unknown signal";
 425                 if (WCOREDUMP(status))
 426                         coredump = " (core dumped)";
 427         }
 428
 429         for (ps = jp->ps ; procno > 0 ; ps++, procno--) { /* for each process */
 430                 if (mode == SHOWJOBS_PIDS || mode == SHOWJOBS_PGIDS) {
 431                         out1fmt("%d\n", (int)ps->pid);
 432                         continue;
 433                 }
 434                 if (mode != SHOWJOBS_VERBOSE && ps != jp->ps)
 435                         continue;
 436                 if (jobno == curr && ps == jp->ps)
 437                         c = '+';
 438                 else if (jobno == prev && ps == jp->ps)
 439                         c = '-';
 440                 else
 441                         c = ' ';
 442                 if (ps == jp->ps)
 443                         fmtstr(s, 64, "[%d] %c ", jobno, c);
 444                 else
 445                         fmtstr(s, 64, "    %c ", c);
 446                 out1str(s);
 447                 col = strlen(s);
 448                 if (mode == SHOWJOBS_VERBOSE) {
 449                         fmtstr(s, 64, "%d ", (int)ps->pid);
 450                         out1str(s);
 451                         col += strlen(s);
 452                 }
 453                 if (ps == jp->ps) {
 454                         out1str(statestr);
 455                         out1str(coredump);
 456                         col += strlen(statestr) + strlen(coredump);
 457                 }
 458                 do {
 459                         out1c(' ');
 460                         col++;
 461                 } while (col < 30);
 462                 if (mode == SHOWJOBS_VERBOSE) {
 463                         out1str(ps->cmd);
 464                         out1c('\n');
 465                 } else
 466                         printjobcmd(jp);
 467         }
 468 }
 469
 470 /*
 471  * Print a list of jobs.  If "change" is nonzero, only print jobs whose
 472  * statuses have changed since the last call to showjobs.
 473  *
 474  * If the shell is interrupted in the process of creating a job, the
 475  * result may be a job structure containing zero processes.  Such structures
 476  * will be freed here.
 477  */
 478
 479 void
 480 showjobs(int change, int mode)
 481 {
 482         int jobno;
 483         struct job *jp;
 484
 485         TRACE(("showjobs(%d) called\n", change));
 486         checkzombies();
 487         for (jobno = 1, jp = jobtab ; jobno <= njobs ; jobno++, jp++) {
 488                 if (! jp->used)
 489                         continue;
 490                 if (jp->nprocs == 0) {
 491                         freejob(jp);
 492                         continue;
 493                 }
 494                 if (change && ! jp->changed)
 495                         continue;
 496                 showjob(jp, mode);
 497                 if (mode == SHOWJOBS_DEFAULT || mode == SHOWJOBS_VERBOSE) {
 498                         jp->changed = 0;
 499                         /* Hack: discard jobs for which $! has not been
 500                          * referenced in interactive mode when they terminate.
 501                          */
 502                         if (jp->state == JOBDONE && !jp->remembered &&
 503                                         (iflag || jp != bgjob)) {
 504                                 freejob(jp);
 505                         }
 506                 }
 507         }
 508 }
 509
 510
 511 /*
 512  * Mark a job structure as unused.
 513  */
 514
 515 static void
 516 freejob(struct job *jp)
 517 {
 518         struct procstat *ps;
 519         int i;
 520
 521         INTOFF;
 522         if (bgjob == jp)
 523                 bgjob = NULL;
 524         for (i = jp->nprocs, ps = jp->ps ; --i >= 0 ; ps++) {
 525                 if (ps->cmd != nullstr)
 526                         ckfree(ps->cmd);
 527         }
 528         if (jp->ps != &jp->ps0)
 529                 ckfree(jp->ps);
 530         jp->used = 0;
 531 #if JOBS
 532         deljob(jp);
 533 #endif
 534         INTON;
 535 }
 536
 537
 538
 539 int
 540 waitcmd(int argc __unused, char **argv __unused)
 541 {
 542         struct job *job;
 543         int retval;
 544
 545         nextopt("");
 546         if (*argptr == NULL)
 547                 return (waitcmdloop(NULL));
 548
 549         do {
 550                 job = getjob_nonotfound(*argptr);
 551                 if (job == NULL)
 552                         retval = 127;
 553                 else
 554                         retval = waitcmdloop(job);
 555                 argptr++;
 556         } while (*argptr != NULL);
 557
 558         return (retval);
 559 }
 560
 561 static int
 562 waitcmdloop(struct job *job)
 563 {
 564         int status, retval, sig;
 565         struct job *jp;
 566
 567         /*
 568          * Loop until a process is terminated or stopped, or a SIGINT is
 569          * received.
 570          */
 571
 572         do {
 573                 if (job != NULL) {
 574                         if (job->state == JOBDONE) {
 575                                 status = getjobstatus(job);
 576                                 if (WIFEXITED(status))
 577                                         retval = WEXITSTATUS(status);
 578                                 else
 579                                         retval = WTERMSIG(status) + 128;
 580                                 if (! iflag || ! job->changed)
 581                                         freejob(job);
 582                                 else {
 583                                         job->remembered = 0;
 584                                         if (job == bgjob)
 585                                                 bgjob = NULL;
 586                                 }
 587                                 return retval;
 588                         }
 589                 } else {
 590                         for (jp = jobtab ; jp < jobtab + njobs; jp++)
 591                                 if (jp->used && jp->state == JOBDONE) {
 592                                         if (! iflag || ! jp->changed)
 593                                                 freejob(jp);
 594                                         else {
 595                                                 jp->remembered = 0;
 596                                                 if (jp == bgjob)
 597                                                         bgjob = NULL;
 598                                         }
 599                                 }
 600                         for (jp = jobtab ; ; jp++) {
 601                                 if (jp >= jobtab + njobs) {     /* no running procs */
 602                                         return 0;
 603                                 }
 604                                 if (jp->used && jp->state == 0)
 605                                         break;
 606                         }
 607                 }
 608         } while (dowait(DOWAIT_BLOCK | DOWAIT_SIG, (struct job *)NULL) != -1);
 609
 610         sig = pendingsig_waitcmd;
 611         pendingsig_waitcmd = 0;
 612         return sig + 128;
 613 }
 614
 615
 616
 617 int
 618 jobidcmd(int argc __unused, char **argv __unused)
 619 {
 620         struct job *jp;
 621         int i;
 622
 623         nextopt("");
 624         jp = getjob(*argptr);
 625         for (i = 0 ; i < jp->nprocs ; ) {
 626                 out1fmt("%d", (int)jp->ps[i].pid);
 627                 out1c(++i < jp->nprocs? ' ' : '\n');
 628         }
 629         return 0;
 630 }
 631
 632
 633
 634 /*
 635  * Convert a job name to a job structure.
 636  */
 637
 638 static struct job *
 639 getjob_nonotfound(const char *name)
 640 {
 641         int jobno;
 642         struct job *found, *jp;
 643         size_t namelen;
 644         pid_t pid;
 645         int i;
 646
 647         if (name == NULL) {
 648 #if JOBS
 649                 name = "%+";
 650 #else
 651                 error("No current job");
 652 #endif
 653         }
 654         if (name[0] == '%') {
 655                 if (is_digit(name[1])) {
 656                         jobno = number(name + 1);
 657                         if (jobno > 0 && jobno <= njobs
 658                          && jobtab[jobno - 1].used != 0)
 659                                 return &jobtab[jobno - 1];
 660 #if JOBS
 661                 } else if ((name[1] == '%' || name[1] == '+') &&
 662                     name[2] == '\0') {
 663                         if ((jp = getcurjob(NULL)) == NULL)
 664                                 error("No current job");
 665                         return (jp);
 666                 } else if (name[1] == '-' && name[2] == '\0') {
 667                         if ((jp = getcurjob(NULL)) == NULL ||
 668                             (jp = getcurjob(jp)) == NULL)
 669                                 error("No previous job");
 670                         return (jp);
 671 #endif
 672                 } else if (name[1] == '?') {
 673                         found = NULL;
 674                         for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
 675                                 if (jp->used && jp->nprocs > 0
 676                                  && strstr(jp->ps[0].cmd, name + 2) != NULL) {
 677                                         if (found)
 678                                                 error("%s: ambiguous", name);
 679                                         found = jp;
 680                                 }
 681                         }
 682                         if (found != NULL)
 683                                 return (found);
 684                 } else {
 685                         namelen = strlen(name);
 686                         found = NULL;
 687                         for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
 688                                 if (jp->used && jp->nprocs > 0
 689                                  && strncmp(jp->ps[0].cmd, name + 1,
 690                                  namelen - 1) == 0) {
 691                                         if (found)
 692                                                 error("%s: ambiguous", name);
 693                                         found = jp;
 694                                 }
 695                         }
 696                         if (found)
 697                                 return found;
 698                 }
 699         } else if (is_number(name)) {
 700                 pid = (pid_t)number(name);
 701                 for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
 702                         if (jp->used && jp->nprocs > 0
 703                          && jp->ps[jp->nprocs - 1].pid == pid)
 704                                 return jp;
 705                 }
 706         }
 707         return NULL;
 708 }
 709
 710
 711 static struct job *
 712 getjob(const char *name)
 713 {
 714         struct job *jp;
 715
 716         jp = getjob_nonotfound(name);
 717         if (jp == NULL)
 718                 error("No such job: %s", name);
 719         return (jp);
 720 }
 721
 722
 723 int
 724 killjob(const char *name, int sig)
 725 {
 726         struct job *jp;
 727         int i, ret;
 728
 729         jp = getjob(name);
 730         if (jp->state == JOBDONE)
 731                 return 0;
 732         if (jp->jobctl)
 733                 return kill(-jp->ps[0].pid, sig);
 734         ret = -1;
 735         errno = ESRCH;
 736         for (i = 0; i < jp->nprocs; i++)
 737                 if (jp->ps[i].status == -1 || WIFSTOPPED(jp->ps[i].status)) {
 738                         if (kill(jp->ps[i].pid, sig) == 0)
 739                                 ret = 0;
 740                 } else
 741                         ret = 0;
 742         return ret;
 743 }
 744
 745 /*
 746  * Return a new job structure,
 747  */
 748
 749 struct job *
 750 makejob(union node *node __unused, int nprocs)
 751 {
 752         int i;
 753         struct job *jp;
 754
 755         for (i = njobs, jp = jobtab ; ; jp++) {
 756                 if (--i < 0) {
 757                         INTOFF;
 758                         if (njobs == 0) {
 759                                 jobtab = ckmalloc(4 * sizeof jobtab[0]);
 760 #if JOBS
 761                                 jobmru = NULL;
 762 #endif
 763                         } else {
 764                                 jp = ckmalloc((njobs + 4) * sizeof jobtab[0]);
 765                                 memcpy(jp, jobtab, njobs * sizeof jp[0]);
 766 #if JOBS
 767                                 /* Relocate `next' pointers and list head */
 768                                 if (jobmru != NULL)
 769                                         jobmru = &jp[jobmru - jobtab];
 770                                 for (i = 0; i < njobs; i++)
 771                                         if (jp[i].next != NULL)
 772                                                 jp[i].next = &jp[jp[i].next -
 773                                                     jobtab];
 774 #endif
 775                                 if (bgjob != NULL)
 776                                         bgjob = &jp[bgjob - jobtab];
 777                                 /* Relocate `ps' pointers */
 778                                 for (i = 0; i < njobs; i++)
 779                                         if (jp[i].ps == &jobtab[i].ps0)
 780                                                 jp[i].ps = &jp[i].ps0;
 781                                 ckfree(jobtab);
 782                                 jobtab = jp;
 783                         }
 784                         jp = jobtab + njobs;
 785                         for (i = 4 ; --i >= 0 ; jobtab[njobs++].used = 0)
 786                                 ;
 787                         INTON;
 788                         break;
 789                 }
 790                 if (jp->used == 0)
 791                         break;
 792         }
 793         INTOFF;
 794         jp->state = 0;
 795         jp->used = 1;
 796         jp->changed = 0;
 797         jp->nprocs = 0;
 798         jp->foreground = 0;
 799         jp->remembered = 0;
 800         jp->pipefail = pipefailflag;
 801 #if JOBS
 802         jp->jobctl = jobctl;
 803         jp->next = NULL;
 804 #endif
 805         if (nprocs > 1) {
 806                 jp->ps = ckmalloc(nprocs * sizeof (struct procstat));
 807         } else {
 808                 jp->ps = &jp->ps0;
 809         }
 810         INTON;
 811         TRACE(("makejob(%p, %d) returns %%%td\n", (void *)node, nprocs,
 812             jp - jobtab + 1));
 813         return jp;
 814 }
 815
 816 #if JOBS
 817 static void
 818 setcurjob(struct job *cj)
 819 {
 820         struct job *jp, *prev;
 821
 822         for (prev = NULL, jp = jobmru; jp != NULL; prev = jp, jp = jp->next) {
 823                 if (jp == cj) {
 824                         if (prev != NULL)
 825                                 prev->next = jp->next;
 826                         else
 827                                 jobmru = jp->next;
 828                         jp->next = jobmru;
 829                         jobmru = cj;
 830                         return;
 831                 }
 832         }
 833         cj->next = jobmru;
 834         jobmru = cj;
 835 }
 836
 837 static void
 838 deljob(struct job *j)
 839 {
 840         struct job *jp, *prev;
 841
 842         for (prev = NULL, jp = jobmru; jp != NULL; prev = jp, jp = jp->next) {
 843                 if (jp == j) {
 844                         if (prev != NULL)
 845                                 prev->next = jp->next;
 846                         else
 847                                 jobmru = jp->next;
 848                         return;
 849                 }
 850         }
 851 }
 852
 853 /*
 854  * Return the most recently used job that isn't `nj', and preferably one
 855  * that is stopped.
 856  */
 857 static struct job *
 858 getcurjob(struct job *nj)
 859 {
 860         struct job *jp;
 861
 862         /* Try to find a stopped one.. */
 863         for (jp = jobmru; jp != NULL; jp = jp->next)
 864                 if (jp->used && jp != nj && jp->state == JOBSTOPPED)
 865                         return (jp);
 866         /* Otherwise the most recently used job that isn't `nj' */
 867         for (jp = jobmru; jp != NULL; jp = jp->next)
 868                 if (jp->used && jp != nj)
 869                         return (jp);
 870
 871         return (NULL);
 872 }
 873
 874 #endif
 875
 876 /*
 877  * Fork of a subshell.  If we are doing job control, give the subshell its
 878  * own process group.  Jp is a job structure that the job is to be added to.
 879  * N is the command that will be evaluated by the child.  Both jp and n may
 880  * be NULL.  The mode parameter can be one of the following:
 881  *      FORK_FG - Fork off a foreground process.
 882  *      FORK_BG - Fork off a background process.
 883  *      FORK_NOJOB - Like FORK_FG, but don't give the process its own
 884  *                   process group even if job control is on.
 885  *
 886  * When job control is turned off, background processes have their standard
 887  * input redirected to /dev/null (except for the second and later processes
 888  * in a pipeline).
 889  */
 890
 891 pid_t
 892 forkshell(struct job *jp, union node *n, int mode)
 893 {
 894         pid_t pid;
 895         pid_t pgrp;
 896
 897         TRACE(("forkshell(%%%td, %p, %d) called\n", jp - jobtab, (void *)n,
 898             mode));
 899         INTOFF;
 900         if (mode == FORK_BG && (jp == NULL || jp->nprocs == 0))
 901                 checkzombies();
 902         flushall();
 903         pid = fork();
 904         if (pid == -1) {
 905                 TRACE(("Fork failed, errno=%d\n", errno));
 906                 INTON;
 907                 error("Cannot fork: %s", strerror(errno));
 908         }
 909         if (pid == 0) {
 910                 struct job *p;
 911                 int wasroot;
 912                 int i;
 913
 914                 TRACE(("Child shell %d\n", (int)getpid()));
 915                 wasroot = rootshell;
 916                 rootshell = 0;
 917                 handler = &main_handler;
 918                 closescript();
 919                 INTON;
 920                 forcelocal = 0;
 921                 clear_traps();
 922 #if JOBS
 923                 jobctl = 0;             /* do job control only in root shell */
 924                 if (wasroot && mode != FORK_NOJOB && mflag) {
 925                         if (jp == NULL || jp->nprocs == 0)
 926                                 pgrp = getpid();
 927                         else
 928                                 pgrp = jp->ps[0].pid;
 929                         if (setpgid(0, pgrp) == 0 && mode == FORK_FG &&
 930                             ttyfd >= 0) {
 931                                 /*** this causes superfluous TIOCSPGRPS ***/
 932                                 if (tcsetpgrp(ttyfd, pgrp) < 0)
 933                                         error("tcsetpgrp failed, errno=%d", errno);
 934                         }
 935                         setsignal(SIGTSTP);
 936                         setsignal(SIGTTOU);
 937                 } else if (mode == FORK_BG) {
 938                         ignoresig(SIGINT);
 939                         ignoresig(SIGQUIT);
 940                         if ((jp == NULL || jp->nprocs == 0) &&
 941                             ! fd0_redirected_p ()) {
 942                                 close(0);
 943                                 if (open(_PATH_DEVNULL, O_RDONLY) != 0)
 944                                         error("cannot open %s: %s",
 945                                             _PATH_DEVNULL, strerror(errno));
 946                         }
 947                 }
 948 #else
 949                 if (mode == FORK_BG) {
 950                         ignoresig(SIGINT);
 951                         ignoresig(SIGQUIT);
 952                         if ((jp == NULL || jp->nprocs == 0) &&
 953                             ! fd0_redirected_p ()) {
 954                                 close(0);
 955                                 if (open(_PATH_DEVNULL, O_RDONLY) != 0)
 956                                         error("cannot open %s: %s",
 957                                             _PATH_DEVNULL, strerror(errno));
 958                         }
 959                 }
 960 #endif
 961                 INTOFF;
 962                 for (i = njobs, p = jobtab ; --i >= 0 ; p++)
 963                         if (p->used)
 964                                 freejob(p);
 965                 INTON;
 966                 if (wasroot && iflag) {
 967                         setsignal(SIGINT);
 968                         setsignal(SIGQUIT);
 969                         setsignal(SIGTERM);
 970                 }
 971                 return pid;
 972         }
 973         if (rootshell && mode != FORK_NOJOB && mflag) {
 974                 if (jp == NULL || jp->nprocs == 0)
 975                         pgrp = pid;
 976                 else
 977                         pgrp = jp->ps[0].pid;
 978                 setpgid(pid, pgrp);
 979         }
 980         if (mode == FORK_BG) {
 981                 if (bgjob != NULL && bgjob->state == JOBDONE &&
 982                     !bgjob->remembered && !iflag)
 983                         freejob(bgjob);
 984                 backgndpid = pid;               /* set $! */
 985                 bgjob = jp;
 986         }
 987         if (jp) {
 988                 struct procstat *ps = &jp->ps[jp->nprocs++];
 989                 ps->pid = pid;
 990                 ps->status = -1;
 991                 ps->cmd = nullstr;
 992                 if (iflag && rootshell && n)
 993                         ps->cmd = commandtext(n);
 994                 jp->foreground = mode == FORK_FG;
 995 #if JOBS
 996                 setcurjob(jp);
 997 #endif
 998         }
 999         INTON;
1000         TRACE(("In parent shell:  child = %d\n", (int)pid));
1001         return pid;
1002 }
1003
1004
1005 pid_t
1006 vforkexecshell(struct job *jp, char **argv, char **envp, const char *path, int idx, int pip[2])
1007 {
1008         pid_t pid;
1009         struct jmploc jmploc;
1010         struct jmploc *savehandler;
1011
1012         TRACE(("vforkexecshell(%%%td, %s, %p) called\n", jp - jobtab, argv[0],
1013             (void *)pip));
1014         INTOFF;
1015         flushall();
1016         savehandler = handler;
1017         pid = vfork();
1018         if (pid == -1) {
1019                 TRACE(("Vfork failed, errno=%d\n", errno));
1020                 INTON;
1021                 error("Cannot fork: %s", strerror(errno));
1022         }
1023         if (pid == 0) {
1024                 TRACE(("Child shell %d\n", (int)getpid()));
1025                 if (setjmp(jmploc.loc))
1026                         _exit(exitstatus);
1027                 if (pip != NULL) {
1028                         close(pip[0]);
1029                         if (pip[1] != 1) {
1030                                 dup2(pip[1], 1);
1031                                 close(pip[1]);
1032                         }
1033                 }
1034                 handler = &jmploc;
1035                 shellexec(argv, envp, path, idx);
1036         }
1037         handler = savehandler;
1038         if (jp) {
1039                 struct procstat *ps = &jp->ps[jp->nprocs++];
1040                 ps->pid = pid;
1041                 ps->status = -1;
1042                 ps->cmd = nullstr;
1043                 jp->foreground = 1;
1044 #if JOBS
1045                 setcurjob(jp);
1046 #endif
1047         }
1048         INTON;
1049         TRACE(("In parent shell:  child = %d\n", (int)pid));
1050         return pid;
1051 }
1052
1053
1054 /*
1055  * Wait for job to finish.
1056  *
1057  * Under job control we have the problem that while a child process is
1058  * running interrupts generated by the user are sent to the child but not
1059  * to the shell.  This means that an infinite loop started by an inter-
1060  * active user may be hard to kill.  With job control turned off, an
1061  * interactive user may place an interactive program inside a loop.  If
1062  * the interactive program catches interrupts, the user doesn't want
1063  * these interrupts to also abort the loop.  The approach we take here
1064  * is to have the shell ignore interrupt signals while waiting for a
1065  * foreground process to terminate, and then send itself an interrupt
1066  * signal if the child process was terminated by an interrupt signal.
1067  * Unfortunately, some programs want to do a bit of cleanup and then
1068  * exit on interrupt; unless these processes terminate themselves by
1069  * sending a signal to themselves (instead of calling exit) they will
1070  * confuse this approach.
1071  */
1072
1073 int
1074 waitforjob(struct job *jp, int *signaled)
1075 {
1076 #if JOBS
1077         int propagate_int = jp->jobctl && jp->foreground;
1078 #endif
1079         int status;
1080         int st;
1081
1082         INTOFF;
1083         TRACE(("waitforjob(%%%td) called\n", jp - jobtab + 1));
1084         while (jp->state == 0)
1085                 if (dowait(DOWAIT_BLOCK | (Tflag ? DOWAIT_SIG |
1086                     DOWAIT_SIG_TRAP : 0), jp) == -1)
1087                         dotrap();
1088 #if JOBS
1089         if (jp->jobctl) {
1090                 if (ttyfd >= 0 && tcsetpgrp(ttyfd, rootpid) < 0)
1091                         error("tcsetpgrp failed, errno=%d\n", errno);
1092         }
1093         if (jp->state == JOBSTOPPED)
1094                 setcurjob(jp);
1095 #endif
1096         status = getjobstatus(jp);
1097         if (signaled != NULL)
1098                 *signaled = WIFSIGNALED(status);
1099         /* convert to 8 bits */
1100         if (WIFEXITED(status))
1101                 st = WEXITSTATUS(status);
1102 #if JOBS
1103         else if (WIFSTOPPED(status))
1104                 st = WSTOPSIG(status) + 128;
1105 #endif
1106         else
1107                 st = WTERMSIG(status) + 128;
1108         if (! JOBS || jp->state == JOBDONE)
1109                 freejob(jp);
1110         if (int_pending()) {
1111                 if (!WIFSIGNALED(status) || WTERMSIG(status) != SIGINT)
1112                         CLEAR_PENDING_INT;
1113         }
1114 #if JOBS
1115         else if (rootshell && propagate_int &&
1116                         WIFSIGNALED(status) && WTERMSIG(status) == SIGINT)
1117                 kill(getpid(), SIGINT);
1118 #endif
1119         INTON;
1120         return st;
1121 }
1122
1123
1124 static void
1125 dummy_handler(int sig __unused)
1126 {
1127 }
1128
1129 /*
1130  * Wait for a process to terminate.
1131  */
1132
1133 static pid_t
1134 dowait(int mode, struct job *job)
1135 {
1136         struct sigaction sa, osa;
1137         sigset_t mask, omask;
1138         pid_t pid;
1139         int status;
1140         struct procstat *sp;
1141         struct job *jp;
1142         struct job *thisjob;
1143         const char *sigstr;
1144         int done;
1145         int stopped;
1146         int sig;
1147         int coredump;
1148         int wflags;
1149         int restore_sigchld;
1150
1151         TRACE(("dowait(%d, %p) called\n", mode, job));
1152         restore_sigchld = 0;
1153         if ((mode & DOWAIT_SIG) != 0) {
1154                 sigfillset(&mask);
1155                 sigprocmask(SIG_BLOCK, &mask, &omask);
1156                 INTOFF;
1157                 if (!issigchldtrapped()) {
1158                         restore_sigchld = 1;
1159                         sa.sa_handler = dummy_handler;
1160                         sa.sa_flags = 0;
1161                         sigemptyset(&sa.sa_mask);
1162                         sigaction(SIGCHLD, &sa, &osa);
1163                 }
1164         }
1165         do {
1166 #if JOBS
1167                 if (iflag)
1168                         wflags = WUNTRACED | WCONTINUED;
1169                 else
1170 #endif
1171                         wflags = 0;
1172                 if ((mode & (DOWAIT_BLOCK | DOWAIT_SIG)) != DOWAIT_BLOCK)
1173                         wflags |= WNOHANG;
1174                 pid = wait3(&status, wflags, (struct rusage *)NULL);
1175                 TRACE(("wait returns %d, status=%d\n", (int)pid, status));
1176                 if (pid == 0 && (mode & DOWAIT_SIG) != 0) {
1177                         pid = -1;
1178                         if (((mode & DOWAIT_SIG_TRAP) != 0 ?
1179                             pendingsig : pendingsig_waitcmd) != 0) {
1180                                 errno = EINTR;
1181                                 break;
1182                         }
1183                         sigsuspend(&omask);
1184                         if (int_pending())
1185                                 break;
1186                 }
1187         } while (pid == -1 && errno == EINTR);
1188         if (pid == -1 && errno == ECHILD && job != NULL)
1189                 job->state = JOBDONE;
1190         if ((mode & DOWAIT_SIG) != 0) {
1191                 if (restore_sigchld)
1192                         sigaction(SIGCHLD, &osa, NULL);
1193                 sigprocmask(SIG_SETMASK, &omask, NULL);
1194                 INTON;
1195         }
1196         if (pid <= 0)
1197                 return pid;
1198         INTOFF;
1199         thisjob = NULL;
1200         for (jp = jobtab ; jp < jobtab + njobs ; jp++) {
1201                 if (jp->used && jp->nprocs > 0) {
1202                         done = 1;
1203                         stopped = 1;
1204                         for (sp = jp->ps ; sp < jp->ps + jp->nprocs ; sp++) {
1205                                 if (sp->pid == -1)
1206                                         continue;
1207                                 if (sp->pid == pid && (sp->status == -1 ||
1208                                     WIFSTOPPED(sp->status))) {
1209                                         TRACE(("Changing status of proc %d from 0x%x to 0x%x\n",
1210                                                    (int)pid, sp->status,
1211                                                    status));
1212                                         if (WIFCONTINUED(status)) {
1213                                                 sp->status = -1;
1214                                                 jp->state = 0;
1215                                         } else
1216                                                 sp->status = status;
1217                                         thisjob = jp;
1218                                 }
1219                                 if (sp->status == -1)
1220                                         stopped = 0;
1221                                 else if (WIFSTOPPED(sp->status))
1222                                         done = 0;
1223                         }
1224                         if (stopped) {          /* stopped or done */
1225                                 int state = done? JOBDONE : JOBSTOPPED;
1226                                 if (jp->state != state) {
1227                                         TRACE(("Job %td: changing state from %d to %d\n", jp - jobtab + 1, jp->state, state));
1228                                         jp->state = state;
1229                                         if (jp != job) {
1230                                                 if (done && !jp->remembered &&
1231                                                     !iflag && jp != bgjob)
1232                                                         freejob(jp);
1233 #if JOBS
1234                                                 else if (done)
1235                                                         deljob(jp);
1236 #endif
1237                                         }
1238                                 }
1239                         }
1240                 }
1241         }
1242         INTON;
1243         if (!thisjob || thisjob->state == 0)
1244                 ;
1245         else if ((!rootshell || !iflag || thisjob == job) &&
1246             thisjob->foreground && thisjob->state != JOBSTOPPED) {
1247                 sig = 0;
1248                 coredump = 0;
1249                 for (sp = thisjob->ps; sp < thisjob->ps + thisjob->nprocs; sp++)
1250                         if (WIFSIGNALED(sp->status)) {
1251                                 sig = WTERMSIG(sp->status);
1252                                 coredump = WCOREDUMP(sp->status);
1253                         }
1254                 if (sig > 0 && sig != SIGINT && sig != SIGPIPE) {
1255                         sigstr = strsignal(sig);
1256                         if (sigstr != NULL)
1257                                 out2str(sigstr);
1258                         else
1259                                 out2str("Unknown signal");
1260                         if (coredump)
1261                                 out2str(" (core dumped)");
1262                         out2c('\n');
1263                         flushout(out2);
1264                 }
1265         } else {
1266                 TRACE(("Not printing status, rootshell=%d, job=%p\n", rootshell, job));
1267                 thisjob->changed = 1;
1268         }
1269         return pid;
1270 }
1271
1272
1273
1274 /*
1275  * return 1 if there are stopped jobs, otherwise 0
1276  */
1277 int job_warning = 0;
1278 int
1279 stoppedjobs(void)
1280 {
1281         int jobno;
1282         struct job *jp;
1283
1284         if (job_warning)
1285                 return (0);
1286         for (jobno = 1, jp = jobtab; jobno <= njobs; jobno++, jp++) {
1287                 if (jp->used == 0)
1288                         continue;
1289                 if (jp->state == JOBSTOPPED) {
1290                         out2fmt_flush("You have stopped jobs.\n");
1291                         job_warning = 2;
1292                         return (1);
1293                 }
1294         }
1295
1296         return (0);
1297 }
1298
1299
1300 static void
1301 checkzombies(void)
1302 {
1303         while (njobs > 0 && dowait(0, NULL) > 0)
1304                 ;
1305 }
1306
1307
1308 int
1309 backgndpidset(void)
1310 {
1311         return backgndpid != -1;
1312 }
1313
1314
1315 pid_t
1316 backgndpidval(void)
1317 {
1318         if (bgjob != NULL && !forcelocal)
1319                 bgjob->remembered = 1;
1320         return backgndpid;
1321 }
1322
1323 /*
1324  * Return a string identifying a command (to be printed by the
1325  * jobs command.
1326  */
1327
1328 static char *cmdnextc;
1329 static int cmdnleft;
1330 #define MAXCMDTEXT      200
1331
1332 char *
1333 commandtext(union node *n)
1334 {
1335         char *name;
1336
1337         cmdnextc = name = ckmalloc(MAXCMDTEXT);
1338         cmdnleft = MAXCMDTEXT - 4;
1339         cmdtxt(n);
1340         *cmdnextc = '\0';
1341         return name;
1342 }
1343
1344
1345 static void
1346 cmdtxtdogroup(union node *n)
1347 {
1348         cmdputs("; do ");
1349         cmdtxt(n);
1350         cmdputs("; done");
1351 }
1352
1353
1354 static void
1355 cmdtxtredir(union node *n, const char *op, int deffd)
1356 {
1357         char s[2];
1358
1359         if (n->nfile.fd != deffd) {
1360                 s[0] = n->nfile.fd + '0';
1361                 s[1] = '\0';
1362                 cmdputs(s);
1363         }
1364         cmdputs(op);
1365         if (n->type == NTOFD || n->type == NFROMFD) {
1366                 if (n->ndup.dupfd >= 0)
1367                         s[0] = n->ndup.dupfd + '0';
1368                 else
1369                         s[0] = '-';
1370                 s[1] = '\0';
1371                 cmdputs(s);
1372         } else {
1373                 cmdtxt(n->nfile.fname);
1374         }
1375 }
1376
1377
1378 static void
1379 cmdtxt(union node *n)
1380 {
1381         union node *np;
1382         struct nodelist *lp;
1383
1384         if (n == NULL)
1385                 return;
1386         switch (n->type) {
1387         case NSEMI:
1388                 cmdtxt(n->nbinary.ch1);
1389                 cmdputs("; ");
1390                 cmdtxt(n->nbinary.ch2);
1391                 break;
1392         case NAND:
1393                 cmdtxt(n->nbinary.ch1);
1394                 cmdputs(" && ");
1395                 cmdtxt(n->nbinary.ch2);
1396                 break;
1397         case NOR:
1398                 cmdtxt(n->nbinary.ch1);
1399                 cmdputs(" || ");
1400                 cmdtxt(n->nbinary.ch2);
1401                 break;
1402         case NPIPE:
1403                 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) {
1404                         cmdtxt(lp->n);
1405                         if (lp->next)
1406                                 cmdputs(" | ");
1407                 }
1408                 break;
1409         case NSUBSHELL:
1410                 cmdputs("(");
1411                 cmdtxt(n->nredir.n);
1412                 cmdputs(")");
1413                 break;
1414         case NREDIR:
1415         case NBACKGND:
1416                 cmdtxt(n->nredir.n);
1417                 break;
1418         case NIF:
1419                 cmdputs("if ");
1420                 cmdtxt(n->nif.test);
1421                 cmdputs("; then ");
1422                 cmdtxt(n->nif.ifpart);
1423                 cmdputs("...");
1424                 break;
1425         case NWHILE:
1426                 cmdputs("while ");
1427                 cmdtxt(n->nbinary.ch1);
1428                 cmdtxtdogroup(n->nbinary.ch2);
1429                 break;
1430         case NUNTIL:
1431                 cmdputs("until ");
1432                 cmdtxt(n->nbinary.ch1);
1433                 cmdtxtdogroup(n->nbinary.ch2);
1434                 break;
1435         case NFOR:
1436                 cmdputs("for ");
1437                 cmdputs(n->nfor.var);
1438                 cmdputs(" in ...");
1439                 break;
1440         case NCASE:
1441                 cmdputs("case ");
1442                 cmdputs(n->ncase.expr->narg.text);
1443                 cmdputs(" in ...");
1444                 break;
1445         case NDEFUN:
1446                 cmdputs(n->narg.text);
1447                 cmdputs("() ...");
1448                 break;
1449         case NNOT:
1450                 cmdputs("! ");
1451                 cmdtxt(n->nnot.com);
1452                 break;
1453         case NCMD:
1454                 for (np = n->ncmd.args ; np ; np = np->narg.next) {
1455                         cmdtxt(np);
1456                         if (np->narg.next)
1457                                 cmdputs(" ");
1458                 }
1459                 for (np = n->ncmd.redirect ; np ; np = np->nfile.next) {
1460                         cmdputs(" ");
1461                         cmdtxt(np);
1462                 }
1463                 break;
1464         case NARG:
1465                 cmdputs(n->narg.text);
1466                 break;
1467         case NTO:
1468                 cmdtxtredir(n, ">", 1);
1469                 break;
1470         case NAPPEND:
1471                 cmdtxtredir(n, ">>", 1);
1472                 break;
1473         case NTOFD:
1474                 cmdtxtredir(n, ">&", 1);
1475                 break;
1476         case NCLOBBER:
1477                 cmdtxtredir(n, ">|", 1);
1478                 break;
1479         case NFROM:
1480                 cmdtxtredir(n, "<", 0);
1481                 break;
1482         case NFROMTO:
1483                 cmdtxtredir(n, "<>", 0);
1484                 break;
1485         case NFROMFD:
1486                 cmdtxtredir(n, "<&", 0);
1487                 break;
1488         case NHERE:
1489         case NXHERE:
1490                 cmdputs("<<...");
1491                 break;
1492         default:
1493                 cmdputs("???");
1494                 break;
1495         }
1496 }
1497
1498
1499
1500 static void
1501 cmdputs(const char *s)
1502 {
1503         const char *p;
1504         char *q;
1505         char c;
1506         int subtype = 0;
1507
1508         if (cmdnleft <= 0)
1509                 return;
1510         p = s;
1511         q = cmdnextc;
1512         while ((c = *p++) != '\0') {
1513                 if (c == CTLESC)
1514                         *q++ = *p++;
1515                 else if (c == CTLVAR) {
1516                         *q++ = '$';
1517                         if (--cmdnleft > 0)
1518                                 *q++ = '{';
1519                         subtype = *p++;
1520                         if ((subtype & VSTYPE) == VSLENGTH && --cmdnleft > 0)
1521                                 *q++ = '#';
1522                 } else if (c == '=' && subtype != 0) {
1523                         *q = "}-+?=##%%\0X"[(subtype & VSTYPE) - VSNORMAL];
1524                         if (*q)
1525                                 q++;
1526                         else
1527                                 cmdnleft++;
1528                         if (((subtype & VSTYPE) == VSTRIMLEFTMAX ||
1529                             (subtype & VSTYPE) == VSTRIMRIGHTMAX) &&
1530                             --cmdnleft > 0)
1531                                 *q = q[-1], q++;
1532                         subtype = 0;
1533                 } else if (c == CTLENDVAR) {
1534                         *q++ = '}';
1535                 } else if (c == CTLBACKQ || c == CTLBACKQ+CTLQUOTE) {
1536                         cmdnleft -= 5;
1537                         if (cmdnleft > 0) {
1538                                 *q++ = '$';
1539                                 *q++ = '(';
1540                                 *q++ = '.';
1541                                 *q++ = '.';
1542                                 *q++ = '.';
1543                                 *q++ = ')';
1544                         }
1545                 } else if (c == CTLARI) {
1546                         cmdnleft -= 2;
1547                         if (cmdnleft > 0) {
1548                                 *q++ = '$';
1549                                 *q++ = '(';
1550                                 *q++ = '(';
1551                         }
1552                         p++;
1553                 } else if (c == CTLENDARI) {
1554                         if (--cmdnleft > 0) {
1555                                 *q++ = ')';
1556                                 *q++ = ')';
1557                         }
1558                 } else if (c == CTLQUOTEMARK || c == CTLQUOTEEND)
1559                         cmdnleft++; /* ignore */
1560                 else
1561                         *q++ = c;
1562                 if (--cmdnleft <= 0) {
1563                         *q++ = '.';
1564                         *q++ = '.';
1565                         *q++ = '.';
1566                         break;
1567                 }
1568         }
1569         cmdnextc = q;
1570 }