ae3bd03896d2979a6e1fde7fbd2c0c8b61585fe6
[dragonfly.git] / bin / sh / jobs.c
1 /*-
2  * Copyright (c) 1991, 1993
3  *      The Regents of the University of California.  All rights reserved.
4  *
5  * This code is derived from software contributed to Berkeley by
6  * Kenneth Almquist.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. All advertising materials mentioning features or use of this software
17  *    must display the following acknowledgement:
18  *      This product includes software developed by the University of
19  *      California, Berkeley and its contributors.
20  * 4. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  *
36  * @(#)jobs.c   8.5 (Berkeley) 5/4/95
37  * $FreeBSD: src/bin/sh/jobs.c,v 1.93 2011/06/04 15:05:52 jilles Exp $
38  */
39
40 #include <sys/ioctl.h>
41 #include <sys/param.h>
42 #include <sys/resource.h>
43 #include <sys/time.h>
44 #include <sys/wait.h>
45 #include <errno.h>
46 #include <fcntl.h>
47 #include <paths.h>
48 #include <signal.h>
49 #include <stddef.h>
50 #include <stdlib.h>
51 #include <unistd.h>
52
53 #include "shell.h"
54 #if JOBS
55 #include <termios.h>
56 #undef CEOF                     /* syntax.h redefines this */
57 #endif
58 #include "redir.h"
59 #include "show.h"
60 #include "main.h"
61 #include "parser.h"
62 #include "nodes.h"
63 #include "jobs.h"
64 #include "options.h"
65 #include "trap.h"
66 #include "syntax.h"
67 #include "input.h"
68 #include "output.h"
69 #include "memalloc.h"
70 #include "error.h"
71 #include "mystring.h"
72
73
74 static struct job *jobtab;      /* array of jobs */
75 static int njobs;               /* size of array */
76 MKINIT pid_t backgndpid = -1;   /* pid of last background process */
77 MKINIT struct job *bgjob = NULL; /* last background process */
78 #if JOBS
79 static struct job *jobmru;      /* most recently used job list */
80 static pid_t initialpgrp;       /* pgrp of shell on invocation */
81 #endif
82 int in_waitcmd = 0;             /* are we in waitcmd()? */
83 int in_dowait = 0;              /* are we in dowait()? */
84 volatile sig_atomic_t breakwaitcmd = 0; /* should wait be terminated? */
85 static int ttyfd = -1;
86
87 #if JOBS
88 static void restartjob(struct job *);
89 #endif
90 static void freejob(struct job *);
91 static struct job *getjob(char *);
92 static pid_t dowait(int, struct job *);
93 static pid_t waitproc(int, int *);
94 static void checkzombies(void);
95 static void cmdtxt(union node *);
96 static void cmdputs(const char *);
97 #if JOBS
98 static void setcurjob(struct job *);
99 static void deljob(struct job *);
100 static struct job *getcurjob(struct job *);
101 #endif
102 static void printjobcmd(struct job *);
103 static void showjob(struct job *, int);
104
105
106 /*
107  * Turn job control on and off.
108  */
109
110 MKINIT int jobctl;
111
112 #if JOBS
113 void
114 setjobctl(int on)
115 {
116         int i;
117
118         if (on == jobctl || rootshell == 0)
119                 return;
120         if (on) {
121                 if (ttyfd != -1)
122                         close(ttyfd);
123                 if ((ttyfd = open(_PATH_TTY, O_RDWR)) < 0) {
124                         i = 0;
125                         while (i <= 2 && !isatty(i))
126                                 i++;
127                         if (i > 2 || (ttyfd = fcntl(i, F_DUPFD, 10)) < 0)
128                                 goto out;
129                 }
130                 if (ttyfd < 10) {
131                         /*
132                          * Keep our TTY file descriptor out of the way of
133                          * the user's redirections.
134                          */
135                         if ((i = fcntl(ttyfd, F_DUPFD, 10)) < 0) {
136                                 close(ttyfd);
137                                 ttyfd = -1;
138                                 goto out;
139                         }
140                         close(ttyfd);
141                         ttyfd = i;
142                 }
143                 if (fcntl(ttyfd, F_SETFD, FD_CLOEXEC) < 0) {
144                         close(ttyfd);
145                         ttyfd = -1;
146                         goto out;
147                 }
148                 do { /* while we are in the background */
149                         initialpgrp = tcgetpgrp(ttyfd);
150                         if (initialpgrp < 0) {
151 out:                            out2fmt_flush("sh: can't access tty; job control turned off\n");
152                                 mflag = 0;
153                                 return;
154                         }
155                         if (initialpgrp != getpgrp()) {
156                                 kill(0, SIGTTIN);
157                                 continue;
158                         }
159                 } while (0);
160                 setsignal(SIGTSTP);
161                 setsignal(SIGTTOU);
162                 setsignal(SIGTTIN);
163                 setpgid(0, rootpid);
164                 tcsetpgrp(ttyfd, rootpid);
165         } else { /* turning job control off */
166                 setpgid(0, initialpgrp);
167                 tcsetpgrp(ttyfd, initialpgrp);
168                 close(ttyfd);
169                 ttyfd = -1;
170                 setsignal(SIGTSTP);
171                 setsignal(SIGTTOU);
172                 setsignal(SIGTTIN);
173         }
174         jobctl = on;
175 }
176 #endif
177
178
179 #if JOBS
180 int
181 fgcmd(int argc __unused, char **argv)
182 {
183         struct job *jp;
184         pid_t pgrp;
185         int status;
186
187         jp = getjob(argv[1]);
188         if (jp->jobctl == 0)
189                 error("job not created under job control");
190         printjobcmd(jp);
191         flushout(&output);
192         pgrp = jp->ps[0].pid;
193         tcsetpgrp(ttyfd, pgrp);
194         restartjob(jp);
195         jp->foreground = 1;
196         INTOFF;
197         status = waitforjob(jp, NULL);
198         INTON;
199         return status;
200 }
201
202
203 int
204 bgcmd(int argc, char **argv)
205 {
206         struct job *jp;
207
208         do {
209                 jp = getjob(*++argv);
210                 if (jp->jobctl == 0)
211                         error("job not created under job control");
212                 if (jp->state == JOBDONE)
213                         continue;
214                 restartjob(jp);
215                 jp->foreground = 0;
216                 out1fmt("[%td] ", jp - jobtab + 1);
217                 printjobcmd(jp);
218         } while (--argc > 1);
219         return 0;
220 }
221
222
223 static void
224 restartjob(struct job *jp)
225 {
226         struct procstat *ps;
227         int i;
228
229         if (jp->state == JOBDONE)
230                 return;
231         setcurjob(jp);
232         INTOFF;
233         kill(-jp->ps[0].pid, SIGCONT);
234         for (ps = jp->ps, i = jp->nprocs ; --i >= 0 ; ps++) {
235                 if (WIFSTOPPED(ps->status)) {
236                         ps->status = -1;
237                         jp->state = 0;
238                 }
239         }
240         INTON;
241 }
242 #endif
243
244
245 int
246 jobscmd(int argc, char *argv[])
247 {
248         char *id;
249         int ch, mode;
250
251         optind = optreset = 1;
252         opterr = 0;
253         mode = SHOWJOBS_DEFAULT;
254         while ((ch = getopt(argc, argv, "lps")) != -1) {
255                 switch (ch) {
256                 case 'l':
257                         mode = SHOWJOBS_VERBOSE;
258                         break;
259                 case 'p':
260                         mode = SHOWJOBS_PGIDS;
261                         break;
262                 case 's':
263                         mode = SHOWJOBS_PIDS;
264                         break;
265                 case '?':
266                 default:
267                         error("unknown option: -%c", optopt);
268                 }
269         }
270         argc -= optind;
271         argv += optind;
272
273         if (argc == 0)
274                 showjobs(0, mode);
275         else
276                 while ((id = *argv++) != NULL)
277                         showjob(getjob(id), mode);
278
279         return (0);
280 }
281
282 static void
283 printjobcmd(struct job *jp)
284 {
285         struct procstat *ps;
286         int i;
287
288         for (ps = jp->ps, i = jp->nprocs ; --i >= 0 ; ps++) {
289                 out1str(ps->cmd);
290                 if (i > 0)
291                         out1str(" | ");
292         }
293         out1c('\n');
294 }
295
296 static void
297 showjob(struct job *jp, int mode)
298 {
299         char s[64];
300         char statestr[64];
301         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                 if (i > 0 && i < sys_nsig && sys_siglist[i])
328                         strcpy(statestr, sys_siglist[i]);
329                 else
330                         strcpy(statestr, "Suspended");
331 #endif
332         } else if (WIFEXITED(ps->status)) {
333                 if (WEXITSTATUS(ps->status) == 0)
334                         strcpy(statestr, "Done");
335                 else
336                         fmtstr(statestr, 64, "Done(%d)",
337                             WEXITSTATUS(ps->status));
338         } else {
339                 i = WTERMSIG(ps->status);
340                 if (i > 0 && i < sys_nsig && sys_siglist[i])
341                         strcpy(statestr, sys_siglist[i]);
342                 else
343                         fmtstr(statestr, 64, "Signal %d", i);
344                 if (WCOREDUMP(ps->status))
345                         strcat(statestr, " (core dumped)");
346         }
347
348         for (ps = jp->ps ; ; ps++) {    /* for each process */
349                 if (mode == SHOWJOBS_PIDS || mode == SHOWJOBS_PGIDS) {
350                         out1fmt("%d\n", (int)ps->pid);
351                         goto skip;
352                 }
353                 if (mode != SHOWJOBS_VERBOSE && ps != jp->ps)
354                         goto skip;
355                 if (jobno == curr && ps == jp->ps)
356                         c = '+';
357                 else if (jobno == prev && ps == jp->ps)
358                         c = '-';
359                 else
360                         c = ' ';
361                 if (ps == jp->ps)
362                         fmtstr(s, 64, "[%d] %c ", jobno, c);
363                 else
364                         fmtstr(s, 64, "    %c ", c);
365                 out1str(s);
366                 col = strlen(s);
367                 if (mode == SHOWJOBS_VERBOSE) {
368                         fmtstr(s, 64, "%d ", (int)ps->pid);
369                         out1str(s);
370                         col += strlen(s);
371                 }
372                 if (ps == jp->ps) {
373                         out1str(statestr);
374                         col += strlen(statestr);
375                 }
376                 do {
377                         out1c(' ');
378                         col++;
379                 } while (col < 30);
380                 if (mode == SHOWJOBS_VERBOSE) {
381                         out1str(ps->cmd);
382                         out1c('\n');
383                 } else
384                         printjobcmd(jp);
385 skip:           if (--procno <= 0)
386                         break;
387         }
388 }
389
390 /*
391  * Print a list of jobs.  If "change" is nonzero, only print jobs whose
392  * statuses have changed since the last call to showjobs.
393  *
394  * If the shell is interrupted in the process of creating a job, the
395  * result may be a job structure containing zero processes.  Such structures
396  * will be freed here.
397  */
398
399 void
400 showjobs(int change, int mode)
401 {
402         int jobno;
403         struct job *jp;
404
405         TRACE(("showjobs(%d) called\n", change));
406         checkzombies();
407         for (jobno = 1, jp = jobtab ; jobno <= njobs ; jobno++, jp++) {
408                 if (! jp->used)
409                         continue;
410                 if (jp->nprocs == 0) {
411                         freejob(jp);
412                         continue;
413                 }
414                 if (change && ! jp->changed)
415                         continue;
416                 showjob(jp, mode);
417                 jp->changed = 0;
418                 /* Hack: discard jobs for which $! has not been referenced
419                  * in interactive mode when they terminate.
420                  */
421                 if (jp->state == JOBDONE && !jp->remembered &&
422                                 (iflag || jp != bgjob)) {
423                         freejob(jp);
424                 }
425         }
426 }
427
428
429 /*
430  * Mark a job structure as unused.
431  */
432
433 static void
434 freejob(struct job *jp)
435 {
436         struct procstat *ps;
437         int i;
438
439         INTOFF;
440         if (bgjob == jp)
441                 bgjob = NULL;
442         for (i = jp->nprocs, ps = jp->ps ; --i >= 0 ; ps++) {
443                 if (ps->cmd != nullstr)
444                         ckfree(ps->cmd);
445         }
446         if (jp->ps != &jp->ps0)
447                 ckfree(jp->ps);
448         jp->used = 0;
449 #if JOBS
450         deljob(jp);
451 #endif
452         INTON;
453 }
454
455
456
457 int
458 waitcmd(int argc, char **argv)
459 {
460         struct job *job;
461         int status, retval;
462         struct job *jp;
463
464         if (argc > 1) {
465                 job = getjob(argv[1]);
466         } else {
467                 job = NULL;
468         }
469
470         /*
471          * Loop until a process is terminated or stopped, or a SIGINT is
472          * received.
473          */
474
475         in_waitcmd++;
476         do {
477                 if (job != NULL) {
478                         if (job->state) {
479                                 status = job->ps[job->nprocs - 1].status;
480                                 if (WIFEXITED(status))
481                                         retval = WEXITSTATUS(status);
482 #if JOBS
483                                 else if (WIFSTOPPED(status))
484                                         retval = WSTOPSIG(status) + 128;
485 #endif
486                                 else
487                                         retval = WTERMSIG(status) + 128;
488                                 if (! iflag || ! job->changed)
489                                         freejob(job);
490                                 else {
491                                         job->remembered = 0;
492                                         if (job == bgjob)
493                                                 bgjob = NULL;
494                                 }
495                                 in_waitcmd--;
496                                 return retval;
497                         }
498                 } else {
499                         for (jp = jobtab ; jp < jobtab + njobs; jp++)
500                                 if (jp->used && jp->state == JOBDONE) {
501                                         if (! iflag || ! jp->changed)
502                                                 freejob(jp);
503                                         else {
504                                                 jp->remembered = 0;
505                                                 if (jp == bgjob)
506                                                         bgjob = NULL;
507                                         }
508                                 }
509                         for (jp = jobtab ; ; jp++) {
510                                 if (jp >= jobtab + njobs) {     /* no running procs */
511                                         in_waitcmd--;
512                                         return 0;
513                                 }
514                                 if (jp->used && jp->state == 0)
515                                         break;
516                         }
517                 }
518         } while (dowait(1, NULL) != -1);
519         in_waitcmd--;
520
521         return 0;
522 }
523
524
525
526 int
527 jobidcmd(int argc __unused, char **argv)
528 {
529         struct job *jp;
530         int i;
531
532         jp = getjob(argv[1]);
533         for (i = 0 ; i < jp->nprocs ; ) {
534                 out1fmt("%d", (int)jp->ps[i].pid);
535                 out1c(++i < jp->nprocs? ' ' : '\n');
536         }
537         return 0;
538 }
539
540
541
542 /*
543  * Convert a job name to a job structure.
544  */
545
546 static struct job *
547 getjob(char *name)
548 {
549         int jobno;
550         struct job *found, *jp;
551         pid_t pid;
552         int i;
553
554         if (name == NULL) {
555 #if JOBS
556 currentjob:     if ((jp = getcurjob(NULL)) == NULL)
557                         error("No current job");
558                 return (jp);
559 #else
560                 error("No current job");
561 #endif
562         } else if (name[0] == '%') {
563                 if (is_digit(name[1])) {
564                         jobno = number(name + 1);
565                         if (jobno > 0 && jobno <= njobs
566                          && jobtab[jobno - 1].used != 0)
567                                 return &jobtab[jobno - 1];
568 #if JOBS
569                 } else if (name[1] == '%' && name[2] == '\0') {
570                         goto currentjob;
571                 } else if (name[1] == '+' && name[2] == '\0') {
572                         goto currentjob;
573                 } else if (name[1] == '-' && name[2] == '\0') {
574                         if ((jp = getcurjob(NULL)) == NULL ||
575                             (jp = getcurjob(jp)) == NULL)
576                                 error("No previous job");
577                         return (jp);
578 #endif
579                 } else if (name[1] == '?') {
580                         found = NULL;
581                         for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
582                                 if (jp->used && jp->nprocs > 0
583                                  && strstr(jp->ps[0].cmd, name + 2) != NULL) {
584                                         if (found)
585                                                 error("%s: ambiguous", name);
586                                         found = jp;
587                                 }
588                         }
589                         if (found != NULL)
590                                 return (found);
591                 } else {
592                         found = NULL;
593                         for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
594                                 if (jp->used && jp->nprocs > 0
595                                  && prefix(name + 1, jp->ps[0].cmd)) {
596                                         if (found)
597                                                 error("%s: ambiguous", name);
598                                         found = jp;
599                                 }
600                         }
601                         if (found)
602                                 return found;
603                 }
604         } else if (is_number(name)) {
605                 pid = (pid_t)number(name);
606                 for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
607                         if (jp->used && jp->nprocs > 0
608                          && jp->ps[jp->nprocs - 1].pid == pid)
609                                 return jp;
610                 }
611         }
612         error("No such job: %s", name);
613         /*NOTREACHED*/
614         return NULL;
615 }
616
617
618 pid_t
619 getjobpgrp(char *name)
620 {
621         struct job *jp;
622
623         jp = getjob(name);
624         return -jp->ps[0].pid;
625 }
626
627 /*
628  * Return a new job structure,
629  */
630
631 struct job *
632 makejob(union node *node __unused, int nprocs)
633 {
634         int i;
635         struct job *jp;
636
637         for (i = njobs, jp = jobtab ; ; jp++) {
638                 if (--i < 0) {
639                         INTOFF;
640                         if (njobs == 0) {
641                                 jobtab = ckmalloc(4 * sizeof jobtab[0]);
642 #if JOBS
643                                 jobmru = NULL;
644 #endif
645                         } else {
646                                 jp = ckmalloc((njobs + 4) * sizeof jobtab[0]);
647                                 memcpy(jp, jobtab, njobs * sizeof jp[0]);
648 #if JOBS
649                                 /* Relocate `next' pointers and list head */
650                                 if (jobmru != NULL)
651                                         jobmru = &jp[jobmru - jobtab];
652                                 for (i = 0; i < njobs; i++)
653                                         if (jp[i].next != NULL)
654                                                 jp[i].next = &jp[jp[i].next -
655                                                     jobtab];
656 #endif
657                                 if (bgjob != NULL)
658                                         bgjob = &jp[bgjob - jobtab];
659                                 /* Relocate `ps' pointers */
660                                 for (i = 0; i < njobs; i++)
661                                         if (jp[i].ps == &jobtab[i].ps0)
662                                                 jp[i].ps = &jp[i].ps0;
663                                 ckfree(jobtab);
664                                 jobtab = jp;
665                         }
666                         jp = jobtab + njobs;
667                         for (i = 4 ; --i >= 0 ; jobtab[njobs++].used = 0);
668                         INTON;
669                         break;
670                 }
671                 if (jp->used == 0)
672                         break;
673         }
674         INTOFF;
675         jp->state = 0;
676         jp->used = 1;
677         jp->changed = 0;
678         jp->nprocs = 0;
679         jp->foreground = 0;
680         jp->remembered = 0;
681 #if JOBS
682         jp->jobctl = jobctl;
683         jp->next = NULL;
684 #endif
685         if (nprocs > 1) {
686                 jp->ps = ckmalloc(nprocs * sizeof (struct procstat));
687         } else {
688                 jp->ps = &jp->ps0;
689         }
690         INTON;
691         TRACE(("makejob(%p, %d) returns %%%td\n", (void *)node, nprocs,
692             jp - jobtab + 1));
693         return jp;
694 }
695
696 #if JOBS
697 static void
698 setcurjob(struct job *cj)
699 {
700         struct job *jp, *prev;
701
702         for (prev = NULL, jp = jobmru; jp != NULL; prev = jp, jp = jp->next) {
703                 if (jp == cj) {
704                         if (prev != NULL)
705                                 prev->next = jp->next;
706                         else
707                                 jobmru = jp->next;
708                         jp->next = jobmru;
709                         jobmru = cj;
710                         return;
711                 }
712         }
713         cj->next = jobmru;
714         jobmru = cj;
715 }
716
717 static void
718 deljob(struct job *j)
719 {
720         struct job *jp, *prev;
721
722         for (prev = NULL, jp = jobmru; jp != NULL; prev = jp, jp = jp->next) {
723                 if (jp == j) {
724                         if (prev != NULL)
725                                 prev->next = jp->next;
726                         else
727                                 jobmru = jp->next;
728                         return;
729                 }
730         }
731 }
732
733 /*
734  * Return the most recently used job that isn't `nj', and preferably one
735  * that is stopped.
736  */
737 static struct job *
738 getcurjob(struct job *nj)
739 {
740         struct job *jp;
741
742         /* Try to find a stopped one.. */
743         for (jp = jobmru; jp != NULL; jp = jp->next)
744                 if (jp->used && jp != nj && jp->state == JOBSTOPPED)
745                         return (jp);
746         /* Otherwise the most recently used job that isn't `nj' */
747         for (jp = jobmru; jp != NULL; jp = jp->next)
748                 if (jp->used && jp != nj)
749                         return (jp);
750
751         return (NULL);
752 }
753
754 #endif
755
756 /*
757  * Fork of a subshell.  If we are doing job control, give the subshell its
758  * own process group.  Jp is a job structure that the job is to be added to.
759  * N is the command that will be evaluated by the child.  Both jp and n may
760  * be NULL.  The mode parameter can be one of the following:
761  *      FORK_FG - Fork off a foreground process.
762  *      FORK_BG - Fork off a background process.
763  *      FORK_NOJOB - Like FORK_FG, but don't give the process its own
764  *                   process group even if job control is on.
765  *
766  * When job control is turned off, background processes have their standard
767  * input redirected to /dev/null (except for the second and later processes
768  * in a pipeline).
769  */
770
771 pid_t
772 forkshell(struct job *jp, union node *n, int mode)
773 {
774         pid_t pid;
775         pid_t pgrp;
776
777         TRACE(("forkshell(%%%td, %p, %d) called\n", jp - jobtab, (void *)n,
778             mode));
779         INTOFF;
780         if (mode == FORK_BG && (jp == NULL || jp->nprocs == 0))
781                 checkzombies();
782         flushall();
783         pid = fork();
784         if (pid == -1) {
785                 TRACE(("Fork failed, errno=%d\n", errno));
786                 INTON;
787                 error("Cannot fork: %s", strerror(errno));
788         }
789         if (pid == 0) {
790                 struct job *p;
791                 int wasroot;
792                 int i;
793
794                 TRACE(("Child shell %d\n", (int)getpid()));
795                 wasroot = rootshell;
796                 rootshell = 0;
797                 handler = &main_handler;
798                 closescript();
799                 INTON;
800                 clear_traps();
801 #if JOBS
802                 jobctl = 0;             /* do job control only in root shell */
803                 if (wasroot && mode != FORK_NOJOB && mflag) {
804                         if (jp == NULL || jp->nprocs == 0)
805                                 pgrp = getpid();
806                         else
807                                 pgrp = jp->ps[0].pid;
808                         if (setpgid(0, pgrp) == 0 && mode == FORK_FG) {
809                                 /*** this causes superfluous TIOCSPGRPS ***/
810                                 if (tcsetpgrp(ttyfd, pgrp) < 0)
811                                         error("tcsetpgrp failed, errno=%d", errno);
812                         }
813                         setsignal(SIGTSTP);
814                         setsignal(SIGTTOU);
815                 } else if (mode == FORK_BG) {
816                         ignoresig(SIGINT);
817                         ignoresig(SIGQUIT);
818                         if ((jp == NULL || jp->nprocs == 0) &&
819                             ! fd0_redirected_p ()) {
820                                 close(0);
821                                 if (open(_PATH_DEVNULL, O_RDONLY) != 0)
822                                         error("cannot open %s: %s",
823                                             _PATH_DEVNULL, strerror(errno));
824                         }
825                 }
826 #else
827                 if (mode == FORK_BG) {
828                         ignoresig(SIGINT);
829                         ignoresig(SIGQUIT);
830                         if ((jp == NULL || jp->nprocs == 0) &&
831                             ! fd0_redirected_p ()) {
832                                 close(0);
833                                 if (open(_PATH_DEVNULL, O_RDONLY) != 0)
834                                         error("cannot open %s: %s",
835                                             _PATH_DEVNULL, strerror(errno));
836                         }
837                 }
838 #endif
839                 INTOFF;
840                 for (i = njobs, p = jobtab ; --i >= 0 ; p++)
841                         if (p->used)
842                                 freejob(p);
843                 INTON;
844                 if (wasroot && iflag) {
845                         setsignal(SIGINT);
846                         setsignal(SIGQUIT);
847                         setsignal(SIGTERM);
848                 }
849                 return pid;
850         }
851         if (rootshell && mode != FORK_NOJOB && mflag) {
852                 if (jp == NULL || jp->nprocs == 0)
853                         pgrp = pid;
854                 else
855                         pgrp = jp->ps[0].pid;
856                 setpgid(pid, pgrp);
857         }
858         if (mode == FORK_BG) {
859                 if (bgjob != NULL && bgjob->state == JOBDONE &&
860                     !bgjob->remembered && !iflag)
861                         freejob(bgjob);
862                 backgndpid = pid;               /* set $! */
863                 bgjob = jp;
864         }
865         if (jp) {
866                 struct procstat *ps = &jp->ps[jp->nprocs++];
867                 ps->pid = pid;
868                 ps->status = -1;
869                 ps->cmd = nullstr;
870                 if (iflag && rootshell && n)
871                         ps->cmd = commandtext(n);
872                 jp->foreground = mode == FORK_FG;
873 #if JOBS
874                 setcurjob(jp);
875 #endif
876         }
877         INTON;
878         TRACE(("In parent shell:  child = %d\n", (int)pid));
879         return pid;
880 }
881
882
883
884 /*
885  * Wait for job to finish.
886  *
887  * Under job control we have the problem that while a child process is
888  * running interrupts generated by the user are sent to the child but not
889  * to the shell.  This means that an infinite loop started by an inter-
890  * active user may be hard to kill.  With job control turned off, an
891  * interactive user may place an interactive program inside a loop.  If
892  * the interactive program catches interrupts, the user doesn't want
893  * these interrupts to also abort the loop.  The approach we take here
894  * is to have the shell ignore interrupt signals while waiting for a
895  * foreground process to terminate, and then send itself an interrupt
896  * signal if the child process was terminated by an interrupt signal.
897  * Unfortunately, some programs want to do a bit of cleanup and then
898  * exit on interrupt; unless these processes terminate themselves by
899  * sending a signal to themselves (instead of calling exit) they will
900  * confuse this approach.
901  */
902
903 int
904 waitforjob(struct job *jp, int *origstatus)
905 {
906 #if JOBS
907         pid_t mypgrp = getpgrp();
908         int propagate_int = jp->jobctl && jp->foreground;
909 #endif
910         int status;
911         int st;
912
913         INTOFF;
914         TRACE(("waitforjob(%%%td) called\n", jp - jobtab + 1));
915         while (jp->state == 0)
916                 if (dowait(1, jp) == -1)
917                         dotrap();
918 #if JOBS
919         if (jp->jobctl) {
920                 if (tcsetpgrp(ttyfd, mypgrp) < 0)
921                         error("tcsetpgrp failed, errno=%d\n", errno);
922         }
923         if (jp->state == JOBSTOPPED)
924                 setcurjob(jp);
925 #endif
926         status = jp->ps[jp->nprocs - 1].status;
927         if (origstatus != NULL)
928                 *origstatus = status;
929         /* convert to 8 bits */
930         if (WIFEXITED(status))
931                 st = WEXITSTATUS(status);
932 #if JOBS
933         else if (WIFSTOPPED(status))
934                 st = WSTOPSIG(status) + 128;
935 #endif
936         else
937                 st = WTERMSIG(status) + 128;
938         if (! JOBS || jp->state == JOBDONE)
939                 freejob(jp);
940         if (int_pending()) {
941                 if (!WIFSIGNALED(status) || WTERMSIG(status) != SIGINT)
942                         CLEAR_PENDING_INT;
943         }
944 #if JOBS
945         else if (rootshell && iflag && propagate_int &&
946                         WIFSIGNALED(status) && WTERMSIG(status) == SIGINT)
947                 kill(getpid(), SIGINT);
948 #endif
949         INTON;
950         return st;
951 }
952
953
954
955 /*
956  * Wait for a process to terminate.
957  */
958
959 static pid_t
960 dowait(int block, struct job *job)
961 {
962         pid_t pid;
963         int status;
964         struct procstat *sp;
965         struct job *jp;
966         struct job *thisjob;
967         int done;
968         int stopped;
969         int sig;
970         int coredump;
971
972         in_dowait++;
973         TRACE(("dowait(%d) called\n", block));
974         do {
975                 pid = waitproc(block, &status);
976                 TRACE(("wait returns %d, status=%d\n", (int)pid, status));
977         } while ((pid == -1 && errno == EINTR && breakwaitcmd == 0) ||
978                  (pid > 0 && WIFSTOPPED(status) && !iflag));
979         in_dowait--;
980         if (pid == -1 && errno == ECHILD && job != NULL)
981                 job->state = JOBDONE;
982         if (breakwaitcmd != 0) {
983                 breakwaitcmd = 0;
984                 /*
985                  * Do not early terminate if the pid is positive, else the
986                  * job will not be properly recorded.
987                  */
988                 if (pid <= 0)
989                         return -1;
990         }
991         if (pid <= 0)
992                 return pid;
993         INTOFF;
994         thisjob = NULL;
995         for (jp = jobtab ; jp < jobtab + njobs ; jp++) {
996                 if (jp->used && jp->nprocs > 0) {
997                         done = 1;
998                         stopped = 1;
999                         for (sp = jp->ps ; sp < jp->ps + jp->nprocs ; sp++) {
1000                                 if (sp->pid == -1)
1001                                         continue;
1002                                 if (sp->pid == pid) {
1003                                         TRACE(("Changing status of proc %d from 0x%x to 0x%x\n",
1004                                                    (int)pid, sp->status,
1005                                                    status));
1006                                         sp->status = status;
1007                                         thisjob = jp;
1008                                 }
1009                                 if (sp->status == -1)
1010                                         stopped = 0;
1011                                 else if (WIFSTOPPED(sp->status))
1012                                         done = 0;
1013                         }
1014                         if (stopped) {          /* stopped or done */
1015                                 int state = done? JOBDONE : JOBSTOPPED;
1016                                 if (jp->state != state) {
1017                                         TRACE(("Job %td: changing state from %d to %d\n", jp - jobtab + 1, jp->state, state));
1018                                         jp->state = state;
1019                                         if (jp != job) {
1020                                                 if (done && !jp->remembered &&
1021                                                     !iflag && jp != bgjob)
1022                                                         freejob(jp);
1023 #if JOBS
1024                                                 else if (done)
1025                                                         deljob(jp);
1026 #endif
1027                                         }
1028                                 }
1029                         }
1030                 }
1031         }
1032         INTON;
1033         if (!thisjob || thisjob->state == 0)
1034                 ;
1035         else if ((!rootshell || !iflag || thisjob == job) &&
1036             thisjob->foreground && thisjob->state != JOBSTOPPED) {
1037                 sig = 0;
1038                 coredump = 0;
1039                 for (sp = thisjob->ps; sp < thisjob->ps + thisjob->nprocs; sp++)
1040                         if (WIFSIGNALED(sp->status)) {
1041                                 sig = WTERMSIG(sp->status);
1042                                 coredump = WCOREDUMP(sp->status);
1043                         }
1044                 if (sig > 0 && sig != SIGINT && sig != SIGPIPE) {
1045                         if (sig < sys_nsig && sys_siglist[sig])
1046                                 out2str(sys_siglist[sig]);
1047                         else
1048                                 outfmt(out2, "Signal %d", sig);
1049                         if (coredump)
1050                                 out2str(" (core dumped)");
1051                         out2c('\n');
1052                         flushout(out2);
1053                 }
1054         } else {
1055                 TRACE(("Not printing status, rootshell=%d, job=%p\n", rootshell, job));
1056                 thisjob->changed = 1;
1057         }
1058         return pid;
1059 }
1060
1061
1062
1063 /*
1064  * Do a wait system call.  If job control is compiled in, we accept
1065  * stopped processes.  If block is zero, we return a value of zero
1066  * rather than blocking.
1067  */
1068 static pid_t
1069 waitproc(int block, int *status)
1070 {
1071         int flags;
1072
1073 #if JOBS
1074         flags = WUNTRACED;
1075 #else
1076         flags = 0;
1077 #endif
1078         if (block == 0)
1079                 flags |= WNOHANG;
1080         return wait3(status, flags, NULL);
1081 }
1082
1083 /*
1084  * return 1 if there are stopped jobs, otherwise 0
1085  */
1086 int job_warning = 0;
1087 int
1088 stoppedjobs(void)
1089 {
1090         int jobno;
1091         struct job *jp;
1092
1093         if (job_warning)
1094                 return (0);
1095         for (jobno = 1, jp = jobtab; jobno <= njobs; jobno++, jp++) {
1096                 if (jp->used == 0)
1097                         continue;
1098                 if (jp->state == JOBSTOPPED) {
1099                         out2fmt_flush("You have stopped jobs.\n");
1100                         job_warning = 2;
1101                         return (1);
1102                 }
1103         }
1104
1105         return (0);
1106 }
1107
1108
1109 static void
1110 checkzombies(void)
1111 {
1112         while (njobs > 0 && dowait(0, NULL) > 0)
1113                 ;
1114 }
1115
1116
1117 int
1118 backgndpidset(void)
1119 {
1120         return backgndpid != -1;
1121 }
1122
1123
1124 pid_t
1125 backgndpidval(void)
1126 {
1127         if (bgjob != NULL)
1128                 bgjob->remembered = 1;
1129         return backgndpid;
1130 }
1131
1132 /*
1133  * Return a string identifying a command (to be printed by the
1134  * jobs command.
1135  */
1136
1137 static char *cmdnextc;
1138 static int cmdnleft;
1139 #define MAXCMDTEXT      200
1140
1141 char *
1142 commandtext(union node *n)
1143 {
1144         char *name;
1145
1146         cmdnextc = name = ckmalloc(MAXCMDTEXT);
1147         cmdnleft = MAXCMDTEXT - 4;
1148         cmdtxt(n);
1149         *cmdnextc = '\0';
1150         return name;
1151 }
1152
1153
1154 static void
1155 cmdtxt(union node *n)
1156 {
1157         union node *np;
1158         struct nodelist *lp;
1159         const char *p;
1160         int i;
1161         char s[2];
1162
1163         if (n == NULL)
1164                 return;
1165         switch (n->type) {
1166         case NSEMI:
1167                 cmdtxt(n->nbinary.ch1);
1168                 cmdputs("; ");
1169                 cmdtxt(n->nbinary.ch2);
1170                 break;
1171         case NAND:
1172                 cmdtxt(n->nbinary.ch1);
1173                 cmdputs(" && ");
1174                 cmdtxt(n->nbinary.ch2);
1175                 break;
1176         case NOR:
1177                 cmdtxt(n->nbinary.ch1);
1178                 cmdputs(" || ");
1179                 cmdtxt(n->nbinary.ch2);
1180                 break;
1181         case NPIPE:
1182                 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) {
1183                         cmdtxt(lp->n);
1184                         if (lp->next)
1185                                 cmdputs(" | ");
1186                 }
1187                 break;
1188         case NSUBSHELL:
1189                 cmdputs("(");
1190                 cmdtxt(n->nredir.n);
1191                 cmdputs(")");
1192                 break;
1193         case NREDIR:
1194         case NBACKGND:
1195                 cmdtxt(n->nredir.n);
1196                 break;
1197         case NIF:
1198                 cmdputs("if ");
1199                 cmdtxt(n->nif.test);
1200                 cmdputs("; then ");
1201                 cmdtxt(n->nif.ifpart);
1202                 cmdputs("...");
1203                 break;
1204         case NWHILE:
1205                 cmdputs("while ");
1206                 goto until;
1207         case NUNTIL:
1208                 cmdputs("until ");
1209 until:
1210                 cmdtxt(n->nbinary.ch1);
1211                 cmdputs("; do ");
1212                 cmdtxt(n->nbinary.ch2);
1213                 cmdputs("; done");
1214                 break;
1215         case NFOR:
1216                 cmdputs("for ");
1217                 cmdputs(n->nfor.var);
1218                 cmdputs(" in ...");
1219                 break;
1220         case NCASE:
1221                 cmdputs("case ");
1222                 cmdputs(n->ncase.expr->narg.text);
1223                 cmdputs(" in ...");
1224                 break;
1225         case NDEFUN:
1226                 cmdputs(n->narg.text);
1227                 cmdputs("() ...");
1228                 break;
1229         case NCMD:
1230                 for (np = n->ncmd.args ; np ; np = np->narg.next) {
1231                         cmdtxt(np);
1232                         if (np->narg.next)
1233                                 cmdputs(" ");
1234                 }
1235                 for (np = n->ncmd.redirect ; np ; np = np->nfile.next) {
1236                         cmdputs(" ");
1237                         cmdtxt(np);
1238                 }
1239                 break;
1240         case NARG:
1241                 cmdputs(n->narg.text);
1242                 break;
1243         case NTO:
1244                 p = ">";  i = 1;  goto redir;
1245         case NAPPEND:
1246                 p = ">>";  i = 1;  goto redir;
1247         case NTOFD:
1248                 p = ">&";  i = 1;  goto redir;
1249         case NCLOBBER:
1250                 p = ">|"; i = 1; goto redir;
1251         case NFROM:
1252                 p = "<";  i = 0;  goto redir;
1253         case NFROMTO:
1254                 p = "<>";  i = 0;  goto redir;
1255         case NFROMFD:
1256                 p = "<&";  i = 0;  goto redir;
1257 redir:
1258                 if (n->nfile.fd != i) {
1259                         s[0] = n->nfile.fd + '0';
1260                         s[1] = '\0';
1261                         cmdputs(s);
1262                 }
1263                 cmdputs(p);
1264                 if (n->type == NTOFD || n->type == NFROMFD) {
1265                         if (n->ndup.dupfd >= 0)
1266                                 s[0] = n->ndup.dupfd + '0';
1267                         else
1268                                 s[0] = '-';
1269                         s[1] = '\0';
1270                         cmdputs(s);
1271                 } else {
1272                         cmdtxt(n->nfile.fname);
1273                 }
1274                 break;
1275         case NHERE:
1276         case NXHERE:
1277                 cmdputs("<<...");
1278                 break;
1279         default:
1280                 cmdputs("???");
1281                 break;
1282         }
1283 }
1284
1285
1286
1287 static void
1288 cmdputs(const char *s)
1289 {
1290         const char *p;
1291         char *q;
1292         char c;
1293         int subtype = 0;
1294
1295         if (cmdnleft <= 0)
1296                 return;
1297         p = s;
1298         q = cmdnextc;
1299         while ((c = *p++) != '\0') {
1300                 if (c == CTLESC)
1301                         *q++ = *p++;
1302                 else if (c == CTLVAR) {
1303                         *q++ = '$';
1304                         if (--cmdnleft > 0)
1305                                 *q++ = '{';
1306                         subtype = *p++;
1307                         if ((subtype & VSTYPE) == VSLENGTH && --cmdnleft > 0)
1308                                 *q++ = '#';
1309                 } else if (c == '=' && subtype != 0) {
1310                         *q = "}-+?=##%%\0X"[(subtype & VSTYPE) - VSNORMAL];
1311                         if (*q)
1312                                 q++;
1313                         else
1314                                 cmdnleft++;
1315                         if (((subtype & VSTYPE) == VSTRIMLEFTMAX ||
1316                             (subtype & VSTYPE) == VSTRIMRIGHTMAX) &&
1317                             --cmdnleft > 0)
1318                                 *q = q[-1], q++;
1319                         subtype = 0;
1320                 } else if (c == CTLENDVAR) {
1321                         *q++ = '}';
1322                 } else if (c == CTLBACKQ || c == CTLBACKQ+CTLQUOTE) {
1323                         cmdnleft -= 5;
1324                         if (cmdnleft > 0) {
1325                                 *q++ = '$';
1326                                 *q++ = '(';
1327                                 *q++ = '.';
1328                                 *q++ = '.';
1329                                 *q++ = '.';
1330                                 *q++ = ')';
1331                         }
1332                 } else if (c == CTLARI) {
1333                         cmdnleft -= 2;
1334                         if (cmdnleft > 0) {
1335                                 *q++ = '$';
1336                                 *q++ = '(';
1337                                 *q++ = '(';
1338                         }
1339                         p++;
1340                 } else if (c == CTLENDARI) {
1341                         if (--cmdnleft > 0) {
1342                                 *q++ = ')';
1343                                 *q++ = ')';
1344                         }
1345                 } else if (c == CTLQUOTEMARK || c == CTLQUOTEEND)
1346                         cmdnleft++; /* ignore */
1347                 else
1348                         *q++ = c;
1349                 if (--cmdnleft <= 0) {
1350                         *q++ = '.';
1351                         *q++ = '.';
1352                         *q++ = '.';
1353                         break;
1354                 }
1355         }
1356         cmdnextc = q;
1357 }