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1 /*-
2  * Copyright (c) 1991, 1993
3  *      The Regents of the University of California.  All rights reserved.
4  *
5  * This code is derived from software contributed to Berkeley by
6  * Kenneth Almquist.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 4. Neither the name of the University nor the names of its contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  */
32
33 #ifndef lint
34 #if 0
35 static char sccsid[] = "@(#)jobs.c      8.5 (Berkeley) 5/4/95";
36 #endif
37 #endif /* not lint */
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
40
41 #include <sys/ioctl.h>
42 #include <sys/param.h>
43 #include <sys/resource.h>
44 #include <sys/time.h>
45 #include <sys/wait.h>
46 #include <errno.h>
47 #include <fcntl.h>
48 #include <paths.h>
49 #include <signal.h>
50 #include <stddef.h>
51 #include <stdlib.h>
52 #include <unistd.h>
53
54 #include "shell.h"
55 #if JOBS
56 #include <termios.h>
57 #undef CEOF                     /* syntax.h redefines this */
58 #endif
59 #include "redir.h"
60 #include "exec.h"
61 #include "show.h"
62 #include "main.h"
63 #include "parser.h"
64 #include "nodes.h"
65 #include "jobs.h"
66 #include "options.h"
67 #include "trap.h"
68 #include "syntax.h"
69 #include "input.h"
70 #include "output.h"
71 #include "memalloc.h"
72 #include "error.h"
73 #include "mystring.h"
74 #include "var.h"
75 #include "builtins.h"
76
77
78 static struct job *jobtab;      /* array of jobs */
79 static int njobs;               /* size of array */
80 static pid_t backgndpid = -1;   /* pid of last background process */
81 static struct job *bgjob = NULL; /* last background process */
82 #if JOBS
83 static struct job *jobmru;      /* most recently used job list */
84 static pid_t initialpgrp;       /* pgrp of shell on invocation */
85 #endif
86 static int ttyfd = -1;
87
88 /* mode flags for dowait */
89 #define DOWAIT_BLOCK    0x1 /* wait until a child exits */
90 #define DOWAIT_SIG      0x2 /* if DOWAIT_BLOCK, abort on SIGINT/SIGQUIT */
91 #define DOWAIT_SIG_ANY  0x4 /* if DOWAIT_SIG, abort on any signal */
92
93 #if JOBS
94 static void restartjob(struct job *);
95 #endif
96 static void freejob(struct job *);
97 static int waitcmdloop(struct job *);
98 static struct job *getjob_nonotfound(char *);
99 static struct job *getjob(char *);
100 pid_t getjobpgrp(char *);
101 static pid_t dowait(int, struct job *);
102 static void checkzombies(void);
103 static void cmdtxt(union node *);
104 static void cmdputs(const char *);
105 #if JOBS
106 static void setcurjob(struct job *);
107 static void deljob(struct job *);
108 static struct job *getcurjob(struct job *);
109 #endif
110 static void printjobcmd(struct job *);
111 static void showjob(struct job *, int);
112
113
114 /*
115  * Turn job control on and off.
116  */
117
118 static int jobctl;
119
120 #if JOBS
121 void
122 setjobctl(int on)
123 {
124         int i;
125
126         if (on == jobctl || rootshell == 0)
127                 return;
128         if (on) {
129                 if (ttyfd != -1)
130                         close(ttyfd);
131                 if ((ttyfd = open(_PATH_TTY, O_RDWR | O_CLOEXEC)) < 0) {
132                         i = 0;
133                         while (i <= 2 && !isatty(i))
134                                 i++;
135                         if (i > 2 ||
136                             (ttyfd = fcntl(i, F_DUPFD_CLOEXEC, 10)) < 0)
137                                 goto out;
138                 }
139                 if (ttyfd < 10) {
140                         /*
141                          * Keep our TTY file descriptor out of the way of
142                          * the user's redirections.
143                          */
144                         if ((i = fcntl(ttyfd, F_DUPFD_CLOEXEC, 10)) < 0) {
145                                 close(ttyfd);
146                                 ttyfd = -1;
147                                 goto out;
148                         }
149                         close(ttyfd);
150                         ttyfd = i;
151                 }
152                 do { /* while we are in the background */
153                         initialpgrp = tcgetpgrp(ttyfd);
154                         if (initialpgrp < 0) {
155 out:                            out2fmt_flush("sh: can't access tty; job control turned off\n");
156                                 mflag = 0;
157                                 return;
158                         }
159                         if (initialpgrp != getpgrp()) {
160                                 kill(0, SIGTTIN);
161                                 continue;
162                         }
163                 } while (0);
164                 setsignal(SIGTSTP);
165                 setsignal(SIGTTOU);
166                 setsignal(SIGTTIN);
167                 setpgid(0, rootpid);
168                 tcsetpgrp(ttyfd, rootpid);
169         } else { /* turning job control off */
170                 setpgid(0, initialpgrp);
171                 tcsetpgrp(ttyfd, initialpgrp);
172                 close(ttyfd);
173                 ttyfd = -1;
174                 setsignal(SIGTSTP);
175                 setsignal(SIGTTOU);
176                 setsignal(SIGTTIN);
177         }
178         jobctl = on;
179 }
180 #endif
181
182
183 #if JOBS
184 int
185 fgcmd(int argc __unused, char **argv __unused)
186 {
187         struct job *jp;
188         pid_t pgrp;
189         int status;
190
191         nextopt("");
192         jp = getjob(*argptr);
193         if (jp->jobctl == 0)
194                 error("job not created under job control");
195         printjobcmd(jp);
196         flushout(&output);
197         pgrp = jp->ps[0].pid;
198         tcsetpgrp(ttyfd, pgrp);
199         restartjob(jp);
200         jp->foreground = 1;
201         INTOFF;
202         status = waitforjob(jp, (int *)NULL);
203         INTON;
204         return status;
205 }
206
207
208 int
209 bgcmd(int argc, char **argv)
210 {
211         struct job *jp;
212
213         nextopt("");
214         do {
215                 jp = getjob(*argptr);
216                 if (jp->jobctl == 0)
217                         error("job not created under job control");
218                 if (jp->state == JOBDONE)
219                         continue;
220                 restartjob(jp);
221                 jp->foreground = 0;
222                 out1fmt("[%td] ", jp - jobtab + 1);
223                 printjobcmd(jp);
224         } while (*argptr != NULL && *++argptr != NULL);
225         return 0;
226 }
227
228
229 static void
230 restartjob(struct job *jp)
231 {
232         struct procstat *ps;
233         int i;
234
235         if (jp->state == JOBDONE)
236                 return;
237         setcurjob(jp);
238         INTOFF;
239         kill(-jp->ps[0].pid, SIGCONT);
240         for (ps = jp->ps, i = jp->nprocs ; --i >= 0 ; ps++) {
241                 if (WIFSTOPPED(ps->status)) {
242                         ps->status = -1;
243                         jp->state = 0;
244                 }
245         }
246         INTON;
247 }
248 #endif
249
250
251 int
252 jobscmd(int argc __unused, char *argv[] __unused)
253 {
254         char *id;
255         int ch, mode;
256
257         mode = SHOWJOBS_DEFAULT;
258         while ((ch = nextopt("lps")) != '\0') {
259                 switch (ch) {
260                 case 'l':
261                         mode = SHOWJOBS_VERBOSE;
262                         break;
263                 case 'p':
264                         mode = SHOWJOBS_PGIDS;
265                         break;
266                 case 's':
267                         mode = SHOWJOBS_PIDS;
268                         break;
269                 }
270         }
271
272         if (*argptr == NULL)
273                 showjobs(0, mode);
274         else
275                 while ((id = *argptr++) != NULL)
276                         showjob(getjob(id), mode);
277
278         return (0);
279 }
280
281 static void
282 printjobcmd(struct job *jp)
283 {
284         struct procstat *ps;
285         int i;
286
287         for (ps = jp->ps, i = jp->nprocs ; --i >= 0 ; ps++) {
288                 out1str(ps->cmd);
289                 if (i > 0)
290                         out1str(" | ");
291         }
292         out1c('\n');
293 }
294
295 static void
296 showjob(struct job *jp, int mode)
297 {
298         char s[64];
299         char statestr[64];
300         const char *sigstr;
301         struct procstat *ps;
302         struct job *j;
303         int col, curr, i, jobno, prev, procno;
304         char c;
305
306         procno = (mode == SHOWJOBS_PGIDS) ? 1 : jp->nprocs;
307         jobno = jp - jobtab + 1;
308         curr = prev = 0;
309 #if JOBS
310         if ((j = getcurjob(NULL)) != NULL) {
311                 curr = j - jobtab + 1;
312                 if ((j = getcurjob(j)) != NULL)
313                         prev = j - jobtab + 1;
314         }
315 #endif
316         ps = jp->ps + jp->nprocs - 1;
317         if (jp->state == 0) {
318                 strcpy(statestr, "Running");
319 #if JOBS
320         } else if (jp->state == JOBSTOPPED) {
321                 while (!WIFSTOPPED(ps->status) && ps > jp->ps)
322                         ps--;
323                 if (WIFSTOPPED(ps->status))
324                         i = WSTOPSIG(ps->status);
325                 else
326                         i = -1;
327                 sigstr = strsignal(i);
328                 if (sigstr != NULL)
329                         strcpy(statestr, sigstr);
330                 else
331                         strcpy(statestr, "Suspended");
332 #endif
333         } else if (WIFEXITED(ps->status)) {
334                 if (WEXITSTATUS(ps->status) == 0)
335                         strcpy(statestr, "Done");
336                 else
337                         fmtstr(statestr, 64, "Done(%d)",
338                             WEXITSTATUS(ps->status));
339         } else {
340                 i = WTERMSIG(ps->status);
341                 sigstr = strsignal(i);
342                 if (sigstr != NULL)
343                         strcpy(statestr, sigstr);
344                 else
345                         strcpy(statestr, "Unknown signal");
346                 if (WCOREDUMP(ps->status))
347                         strcat(statestr, " (core dumped)");
348         }
349
350         for (ps = jp->ps ; ; ps++) {    /* for each process */
351                 if (mode == SHOWJOBS_PIDS || mode == SHOWJOBS_PGIDS) {
352                         out1fmt("%d\n", (int)ps->pid);
353                         goto skip;
354                 }
355                 if (mode != SHOWJOBS_VERBOSE && ps != jp->ps)
356                         goto skip;
357                 if (jobno == curr && ps == jp->ps)
358                         c = '+';
359                 else if (jobno == prev && ps == jp->ps)
360                         c = '-';
361                 else
362                         c = ' ';
363                 if (ps == jp->ps)
364                         fmtstr(s, 64, "[%d] %c ", jobno, c);
365                 else
366                         fmtstr(s, 64, "    %c ", c);
367                 out1str(s);
368                 col = strlen(s);
369                 if (mode == SHOWJOBS_VERBOSE) {
370                         fmtstr(s, 64, "%d ", (int)ps->pid);
371                         out1str(s);
372                         col += strlen(s);
373                 }
374                 if (ps == jp->ps) {
375                         out1str(statestr);
376                         col += strlen(statestr);
377                 }
378                 do {
379                         out1c(' ');
380                         col++;
381                 } while (col < 30);
382                 if (mode == SHOWJOBS_VERBOSE) {
383                         out1str(ps->cmd);
384                         out1c('\n');
385                 } else
386                         printjobcmd(jp);
387 skip:           if (--procno <= 0)
388                         break;
389         }
390 }
391
392 /*
393  * Print a list of jobs.  If "change" is nonzero, only print jobs whose
394  * statuses have changed since the last call to showjobs.
395  *
396  * If the shell is interrupted in the process of creating a job, the
397  * result may be a job structure containing zero processes.  Such structures
398  * will be freed here.
399  */
400
401 void
402 showjobs(int change, int mode)
403 {
404         int jobno;
405         struct job *jp;
406
407         TRACE(("showjobs(%d) called\n", change));
408         checkzombies();
409         for (jobno = 1, jp = jobtab ; jobno <= njobs ; jobno++, jp++) {
410                 if (! jp->used)
411                         continue;
412                 if (jp->nprocs == 0) {
413                         freejob(jp);
414                         continue;
415                 }
416                 if (change && ! jp->changed)
417                         continue;
418                 showjob(jp, mode);
419                 if (mode == SHOWJOBS_DEFAULT || mode == SHOWJOBS_VERBOSE) {
420                         jp->changed = 0;
421                         /* Hack: discard jobs for which $! has not been
422                          * referenced in interactive mode when they terminate.
423                          */
424                         if (jp->state == JOBDONE && !jp->remembered &&
425                                         (iflag || jp != bgjob)) {
426                                 freejob(jp);
427                         }
428                 }
429         }
430 }
431
432
433 /*
434  * Mark a job structure as unused.
435  */
436
437 static void
438 freejob(struct job *jp)
439 {
440         struct procstat *ps;
441         int i;
442
443         INTOFF;
444         if (bgjob == jp)
445                 bgjob = NULL;
446         for (i = jp->nprocs, ps = jp->ps ; --i >= 0 ; ps++) {
447                 if (ps->cmd != nullstr)
448                         ckfree(ps->cmd);
449         }
450         if (jp->ps != &jp->ps0)
451                 ckfree(jp->ps);
452         jp->used = 0;
453 #if JOBS
454         deljob(jp);
455 #endif
456         INTON;
457 }
458
459
460
461 int
462 waitcmd(int argc __unused, char **argv __unused)
463 {
464         struct job *job;
465         int retval;
466
467         nextopt("");
468         if (*argptr == NULL)
469                 return (waitcmdloop(NULL));
470
471         do {
472                 job = getjob_nonotfound(*argptr);
473                 if (job == NULL)
474                         retval = 127;
475                 else
476                         retval = waitcmdloop(job);
477                 argptr++;
478         } while (*argptr != NULL);
479
480         return (retval);
481 }
482
483 static int
484 waitcmdloop(struct job *job)
485 {
486         int status, retval, sig;
487         struct job *jp;
488
489         /*
490          * Loop until a process is terminated or stopped, or a SIGINT is
491          * received.
492          */
493
494         do {
495                 if (job != NULL) {
496                         if (job->state == JOBDONE) {
497                                 status = job->ps[job->nprocs - 1].status;
498                                 if (WIFEXITED(status))
499                                         retval = WEXITSTATUS(status);
500                                 else
501                                         retval = WTERMSIG(status) + 128;
502                                 if (! iflag || ! job->changed)
503                                         freejob(job);
504                                 else {
505                                         job->remembered = 0;
506                                         if (job == bgjob)
507                                                 bgjob = NULL;
508                                 }
509                                 return retval;
510                         }
511                 } else {
512                         for (jp = jobtab ; jp < jobtab + njobs; jp++)
513                                 if (jp->used && jp->state == JOBDONE) {
514                                         if (! iflag || ! jp->changed)
515                                                 freejob(jp);
516                                         else {
517                                                 jp->remembered = 0;
518                                                 if (jp == bgjob)
519                                                         bgjob = NULL;
520                                         }
521                                 }
522                         for (jp = jobtab ; ; jp++) {
523                                 if (jp >= jobtab + njobs) {     /* no running procs */
524                                         return 0;
525                                 }
526                                 if (jp->used && jp->state == 0)
527                                         break;
528                         }
529                 }
530         } while (dowait(DOWAIT_BLOCK | DOWAIT_SIG, (struct job *)NULL) != -1);
531
532         sig = pendingsig_waitcmd;
533         pendingsig_waitcmd = 0;
534         return sig + 128;
535 }
536
537
538
539 int
540 jobidcmd(int argc __unused, char **argv __unused)
541 {
542         struct job *jp;
543         int i;
544
545         nextopt("");
546         jp = getjob(*argptr);
547         for (i = 0 ; i < jp->nprocs ; ) {
548                 out1fmt("%d", (int)jp->ps[i].pid);
549                 out1c(++i < jp->nprocs? ' ' : '\n');
550         }
551         return 0;
552 }
553
554
555
556 /*
557  * Convert a job name to a job structure.
558  */
559
560 static struct job *
561 getjob_nonotfound(char *name)
562 {
563         int jobno;
564         struct job *found, *jp;
565         pid_t pid;
566         int i;
567
568         if (name == NULL) {
569 #if JOBS
570 currentjob:     if ((jp = getcurjob(NULL)) == NULL)
571                         error("No current job");
572                 return (jp);
573 #else
574                 error("No current job");
575 #endif
576         } else if (name[0] == '%') {
577                 if (is_digit(name[1])) {
578                         jobno = number(name + 1);
579                         if (jobno > 0 && jobno <= njobs
580                          && jobtab[jobno - 1].used != 0)
581                                 return &jobtab[jobno - 1];
582 #if JOBS
583                 } else if (name[1] == '%' && name[2] == '\0') {
584                         goto currentjob;
585                 } else if (name[1] == '+' && name[2] == '\0') {
586                         goto currentjob;
587                 } else if (name[1] == '-' && name[2] == '\0') {
588                         if ((jp = getcurjob(NULL)) == NULL ||
589                             (jp = getcurjob(jp)) == NULL)
590                                 error("No previous job");
591                         return (jp);
592 #endif
593                 } else if (name[1] == '?') {
594                         found = NULL;
595                         for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
596                                 if (jp->used && jp->nprocs > 0
597                                  && strstr(jp->ps[0].cmd, name + 2) != NULL) {
598                                         if (found)
599                                                 error("%s: ambiguous", name);
600                                         found = jp;
601                                 }
602                         }
603                         if (found != NULL)
604                                 return (found);
605                 } else {
606                         found = NULL;
607                         for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
608                                 if (jp->used && jp->nprocs > 0
609                                  && prefix(name + 1, jp->ps[0].cmd)) {
610                                         if (found)
611                                                 error("%s: ambiguous", name);
612                                         found = jp;
613                                 }
614                         }
615                         if (found)
616                                 return found;
617                 }
618         } else if (is_number(name)) {
619                 pid = (pid_t)number(name);
620                 for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
621                         if (jp->used && jp->nprocs > 0
622                          && jp->ps[jp->nprocs - 1].pid == pid)
623                                 return jp;
624                 }
625         }
626         return NULL;
627 }
628
629
630 static struct job *
631 getjob(char *name)
632 {
633         struct job *jp;
634
635         jp = getjob_nonotfound(name);
636         if (jp == NULL)
637                 error("No such job: %s", name);
638         return (jp);
639 }
640
641
642 pid_t
643 getjobpgrp(char *name)
644 {
645         struct job *jp;
646
647         jp = getjob(name);
648         return -jp->ps[0].pid;
649 }
650
651 /*
652  * Return a new job structure,
653  */
654
655 struct job *
656 makejob(union node *node __unused, int nprocs)
657 {
658         int i;
659         struct job *jp;
660
661         for (i = njobs, jp = jobtab ; ; jp++) {
662                 if (--i < 0) {
663                         INTOFF;
664                         if (njobs == 0) {
665                                 jobtab = ckmalloc(4 * sizeof jobtab[0]);
666 #if JOBS
667                                 jobmru = NULL;
668 #endif
669                         } else {
670                                 jp = ckmalloc((njobs + 4) * sizeof jobtab[0]);
671                                 memcpy(jp, jobtab, njobs * sizeof jp[0]);
672 #if JOBS
673                                 /* Relocate `next' pointers and list head */
674                                 if (jobmru != NULL)
675                                         jobmru = &jp[jobmru - jobtab];
676                                 for (i = 0; i < njobs; i++)
677                                         if (jp[i].next != NULL)
678                                                 jp[i].next = &jp[jp[i].next -
679                                                     jobtab];
680 #endif
681                                 if (bgjob != NULL)
682                                         bgjob = &jp[bgjob - jobtab];
683                                 /* Relocate `ps' pointers */
684                                 for (i = 0; i < njobs; i++)
685                                         if (jp[i].ps == &jobtab[i].ps0)
686                                                 jp[i].ps = &jp[i].ps0;
687                                 ckfree(jobtab);
688                                 jobtab = jp;
689                         }
690                         jp = jobtab + njobs;
691                         for (i = 4 ; --i >= 0 ; jobtab[njobs++].used = 0)
692                                 ;
693                         INTON;
694                         break;
695                 }
696                 if (jp->used == 0)
697                         break;
698         }
699         INTOFF;
700         jp->state = 0;
701         jp->used = 1;
702         jp->changed = 0;
703         jp->nprocs = 0;
704         jp->foreground = 0;
705         jp->remembered = 0;
706 #if JOBS
707         jp->jobctl = jobctl;
708         jp->next = NULL;
709 #endif
710         if (nprocs > 1) {
711                 jp->ps = ckmalloc(nprocs * sizeof (struct procstat));
712         } else {
713                 jp->ps = &jp->ps0;
714         }
715         INTON;
716         TRACE(("makejob(%p, %d) returns %%%td\n", (void *)node, nprocs,
717             jp - jobtab + 1));
718         return jp;
719 }
720
721 #if JOBS
722 static void
723 setcurjob(struct job *cj)
724 {
725         struct job *jp, *prev;
726
727         for (prev = NULL, jp = jobmru; jp != NULL; prev = jp, jp = jp->next) {
728                 if (jp == cj) {
729                         if (prev != NULL)
730                                 prev->next = jp->next;
731                         else
732                                 jobmru = jp->next;
733                         jp->next = jobmru;
734                         jobmru = cj;
735                         return;
736                 }
737         }
738         cj->next = jobmru;
739         jobmru = cj;
740 }
741
742 static void
743 deljob(struct job *j)
744 {
745         struct job *jp, *prev;
746
747         for (prev = NULL, jp = jobmru; jp != NULL; prev = jp, jp = jp->next) {
748                 if (jp == j) {
749                         if (prev != NULL)
750                                 prev->next = jp->next;
751                         else
752                                 jobmru = jp->next;
753                         return;
754                 }
755         }
756 }
757
758 /*
759  * Return the most recently used job that isn't `nj', and preferably one
760  * that is stopped.
761  */
762 static struct job *
763 getcurjob(struct job *nj)
764 {
765         struct job *jp;
766
767         /* Try to find a stopped one.. */
768         for (jp = jobmru; jp != NULL; jp = jp->next)
769                 if (jp->used && jp != nj && jp->state == JOBSTOPPED)
770                         return (jp);
771         /* Otherwise the most recently used job that isn't `nj' */
772         for (jp = jobmru; jp != NULL; jp = jp->next)
773                 if (jp->used && jp != nj)
774                         return (jp);
775
776         return (NULL);
777 }
778
779 #endif
780
781 /*
782  * Fork of a subshell.  If we are doing job control, give the subshell its
783  * own process group.  Jp is a job structure that the job is to be added to.
784  * N is the command that will be evaluated by the child.  Both jp and n may
785  * be NULL.  The mode parameter can be one of the following:
786  *      FORK_FG - Fork off a foreground process.
787  *      FORK_BG - Fork off a background process.
788  *      FORK_NOJOB - Like FORK_FG, but don't give the process its own
789  *                   process group even if job control is on.
790  *
791  * When job control is turned off, background processes have their standard
792  * input redirected to /dev/null (except for the second and later processes
793  * in a pipeline).
794  */
795
796 pid_t
797 forkshell(struct job *jp, union node *n, int mode)
798 {
799         pid_t pid;
800         pid_t pgrp;
801
802         TRACE(("forkshell(%%%td, %p, %d) called\n", jp - jobtab, (void *)n,
803             mode));
804         INTOFF;
805         if (mode == FORK_BG && (jp == NULL || jp->nprocs == 0))
806                 checkzombies();
807         flushall();
808         pid = fork();
809         if (pid == -1) {
810                 TRACE(("Fork failed, errno=%d\n", errno));
811                 INTON;
812                 error("Cannot fork: %s", strerror(errno));
813         }
814         if (pid == 0) {
815                 struct job *p;
816                 int wasroot;
817                 int i;
818
819                 TRACE(("Child shell %d\n", (int)getpid()));
820                 wasroot = rootshell;
821                 rootshell = 0;
822                 handler = &main_handler;
823                 closescript();
824                 INTON;
825                 forcelocal = 0;
826                 clear_traps();
827 #if JOBS
828                 jobctl = 0;             /* do job control only in root shell */
829                 if (wasroot && mode != FORK_NOJOB && mflag) {
830                         if (jp == NULL || jp->nprocs == 0)
831                                 pgrp = getpid();
832                         else
833                                 pgrp = jp->ps[0].pid;
834                         if (setpgid(0, pgrp) == 0 && mode == FORK_FG) {
835                                 /*** this causes superfluous TIOCSPGRPS ***/
836                                 if (tcsetpgrp(ttyfd, pgrp) < 0)
837                                         error("tcsetpgrp failed, errno=%d", errno);
838                         }
839                         setsignal(SIGTSTP);
840                         setsignal(SIGTTOU);
841                 } else if (mode == FORK_BG) {
842                         ignoresig(SIGINT);
843                         ignoresig(SIGQUIT);
844                         if ((jp == NULL || jp->nprocs == 0) &&
845                             ! fd0_redirected_p ()) {
846                                 close(0);
847                                 if (open(_PATH_DEVNULL, O_RDONLY) != 0)
848                                         error("cannot open %s: %s",
849                                             _PATH_DEVNULL, strerror(errno));
850                         }
851                 }
852 #else
853                 if (mode == FORK_BG) {
854                         ignoresig(SIGINT);
855                         ignoresig(SIGQUIT);
856                         if ((jp == NULL || jp->nprocs == 0) &&
857                             ! fd0_redirected_p ()) {
858                                 close(0);
859                                 if (open(_PATH_DEVNULL, O_RDONLY) != 0)
860                                         error("cannot open %s: %s",
861                                             _PATH_DEVNULL, strerror(errno));
862                         }
863                 }
864 #endif
865                 INTOFF;
866                 for (i = njobs, p = jobtab ; --i >= 0 ; p++)
867                         if (p->used)
868                                 freejob(p);
869                 INTON;
870                 if (wasroot && iflag) {
871                         setsignal(SIGINT);
872                         setsignal(SIGQUIT);
873                         setsignal(SIGTERM);
874                 }
875                 return pid;
876         }
877         if (rootshell && mode != FORK_NOJOB && mflag) {
878                 if (jp == NULL || jp->nprocs == 0)
879                         pgrp = pid;
880                 else
881                         pgrp = jp->ps[0].pid;
882                 setpgid(pid, pgrp);
883         }
884         if (mode == FORK_BG) {
885                 if (bgjob != NULL && bgjob->state == JOBDONE &&
886                     !bgjob->remembered && !iflag)
887                         freejob(bgjob);
888                 backgndpid = pid;               /* set $! */
889                 bgjob = jp;
890         }
891         if (jp) {
892                 struct procstat *ps = &jp->ps[jp->nprocs++];
893                 ps->pid = pid;
894                 ps->status = -1;
895                 ps->cmd = nullstr;
896                 if (iflag && rootshell && n)
897                         ps->cmd = commandtext(n);
898                 jp->foreground = mode == FORK_FG;
899 #if JOBS
900                 setcurjob(jp);
901 #endif
902         }
903         INTON;
904         TRACE(("In parent shell:  child = %d\n", (int)pid));
905         return pid;
906 }
907
908
909 pid_t
910 vforkexecshell(struct job *jp, char **argv, char **envp, const char *path, int idx, int pip[2])
911 {
912         pid_t pid;
913         struct jmploc jmploc;
914         struct jmploc *savehandler;
915
916         TRACE(("vforkexecshell(%%%td, %s, %p) called\n", jp - jobtab, argv[0],
917             (void *)pip));
918         INTOFF;
919         flushall();
920         savehandler = handler;
921         pid = vfork();
922         if (pid == -1) {
923                 TRACE(("Vfork failed, errno=%d\n", errno));
924                 INTON;
925                 error("Cannot fork: %s", strerror(errno));
926         }
927         if (pid == 0) {
928                 TRACE(("Child shell %d\n", (int)getpid()));
929                 if (setjmp(jmploc.loc))
930                         _exit(exception == EXEXEC ? exerrno : 2);
931                 if (pip != NULL) {
932                         close(pip[0]);
933                         if (pip[1] != 1) {
934                                 dup2(pip[1], 1);
935                                 close(pip[1]);
936                         }
937                 }
938                 handler = &jmploc;
939                 shellexec(argv, envp, path, idx);
940         }
941         handler = savehandler;
942         if (jp) {
943                 struct procstat *ps = &jp->ps[jp->nprocs++];
944                 ps->pid = pid;
945                 ps->status = -1;
946                 ps->cmd = nullstr;
947                 jp->foreground = 1;
948 #if JOBS
949                 setcurjob(jp);
950 #endif
951         }
952         INTON;
953         TRACE(("In parent shell:  child = %d\n", (int)pid));
954         return pid;
955 }
956
957
958 /*
959  * Wait for job to finish.
960  *
961  * Under job control we have the problem that while a child process is
962  * running interrupts generated by the user are sent to the child but not
963  * to the shell.  This means that an infinite loop started by an inter-
964  * active user may be hard to kill.  With job control turned off, an
965  * interactive user may place an interactive program inside a loop.  If
966  * the interactive program catches interrupts, the user doesn't want
967  * these interrupts to also abort the loop.  The approach we take here
968  * is to have the shell ignore interrupt signals while waiting for a
969  * foreground process to terminate, and then send itself an interrupt
970  * signal if the child process was terminated by an interrupt signal.
971  * Unfortunately, some programs want to do a bit of cleanup and then
972  * exit on interrupt; unless these processes terminate themselves by
973  * sending a signal to themselves (instead of calling exit) they will
974  * confuse this approach.
975  */
976
977 int
978 waitforjob(struct job *jp, int *origstatus)
979 {
980 #if JOBS
981         pid_t mypgrp = getpgrp();
982         int propagate_int = jp->jobctl && jp->foreground;
983 #endif
984         int status;
985         int st;
986
987         INTOFF;
988         TRACE(("waitforjob(%%%td) called\n", jp - jobtab + 1));
989         while (jp->state == 0)
990                 if (dowait(DOWAIT_BLOCK | (Tflag ? DOWAIT_SIG |
991                     DOWAIT_SIG_ANY : 0), jp) == -1)
992                         dotrap();
993 #if JOBS
994         if (jp->jobctl) {
995                 if (tcsetpgrp(ttyfd, mypgrp) < 0)
996                         error("tcsetpgrp failed, errno=%d\n", errno);
997         }
998         if (jp->state == JOBSTOPPED)
999                 setcurjob(jp);
1000 #endif
1001         status = jp->ps[jp->nprocs - 1].status;
1002         if (origstatus != NULL)
1003                 *origstatus = status;
1004         /* convert to 8 bits */
1005         if (WIFEXITED(status))
1006                 st = WEXITSTATUS(status);
1007 #if JOBS
1008         else if (WIFSTOPPED(status))
1009                 st = WSTOPSIG(status) + 128;
1010 #endif
1011         else
1012                 st = WTERMSIG(status) + 128;
1013         if (! JOBS || jp->state == JOBDONE)
1014                 freejob(jp);
1015         if (int_pending()) {
1016                 if (!WIFSIGNALED(status) || WTERMSIG(status) != SIGINT)
1017                         CLEAR_PENDING_INT;
1018         }
1019 #if JOBS
1020         else if (rootshell && iflag && propagate_int &&
1021                         WIFSIGNALED(status) && WTERMSIG(status) == SIGINT)
1022                 kill(getpid(), SIGINT);
1023 #endif
1024         INTON;
1025         return st;
1026 }
1027
1028
1029 static void
1030 dummy_handler(int sig __unused)
1031 {
1032 }
1033
1034 /*
1035  * Wait for a process to terminate.
1036  */
1037
1038 static pid_t
1039 dowait(int mode, struct job *job)
1040 {
1041         struct sigaction sa, osa;
1042         sigset_t mask, omask;
1043         pid_t pid;
1044         int status;
1045         struct procstat *sp;
1046         struct job *jp;
1047         struct job *thisjob;
1048         const char *sigstr;
1049         int done;
1050         int stopped;
1051         int sig;
1052         int coredump;
1053         int wflags;
1054         int restore_sigchld;
1055
1056         TRACE(("dowait(%d, %p) called\n", mode, job));
1057         restore_sigchld = 0;
1058         if ((mode & DOWAIT_SIG) != 0) {
1059                 sigfillset(&mask);
1060                 sigprocmask(SIG_BLOCK, &mask, &omask);
1061                 INTOFF;
1062                 if (!issigchldtrapped()) {
1063                         restore_sigchld = 1;
1064                         sa.sa_handler = dummy_handler;
1065                         sa.sa_flags = 0;
1066                         sigemptyset(&sa.sa_mask);
1067                         sigaction(SIGCHLD, &sa, &osa);
1068                 }
1069         }
1070         do {
1071 #if JOBS
1072                 if (iflag)
1073                         wflags = WUNTRACED | WCONTINUED;
1074                 else
1075 #endif
1076                         wflags = 0;
1077                 if ((mode & (DOWAIT_BLOCK | DOWAIT_SIG)) != DOWAIT_BLOCK)
1078                         wflags |= WNOHANG;
1079                 pid = wait3(&status, wflags, (struct rusage *)NULL);
1080                 TRACE(("wait returns %d, status=%d\n", (int)pid, status));
1081                 if (pid == 0 && (mode & DOWAIT_SIG) != 0) {
1082                         pid = -1;
1083                         if (((mode & DOWAIT_SIG_ANY) != 0 ?
1084                             pendingsig : pendingsig_waitcmd) != 0) {
1085                                 errno = EINTR;
1086                                 break;
1087                         }
1088                         sigsuspend(&omask);
1089                         if (int_pending())
1090                                 break;
1091                 }
1092         } while (pid == -1 && errno == EINTR);
1093         if (pid == -1 && errno == ECHILD && job != NULL)
1094                 job->state = JOBDONE;
1095         if ((mode & DOWAIT_SIG) != 0) {
1096                 if (restore_sigchld)
1097                         sigaction(SIGCHLD, &osa, NULL);
1098                 sigprocmask(SIG_SETMASK, &omask, NULL);
1099                 INTON;
1100         }
1101         if (pid <= 0)
1102                 return pid;
1103         INTOFF;
1104         thisjob = NULL;
1105         for (jp = jobtab ; jp < jobtab + njobs ; jp++) {
1106                 if (jp->used && jp->nprocs > 0) {
1107                         done = 1;
1108                         stopped = 1;
1109                         for (sp = jp->ps ; sp < jp->ps + jp->nprocs ; sp++) {
1110                                 if (sp->pid == -1)
1111                                         continue;
1112                                 if (sp->pid == pid) {
1113                                         TRACE(("Changing status of proc %d from 0x%x to 0x%x\n",
1114                                                    (int)pid, sp->status,
1115                                                    status));
1116                                         if (WIFCONTINUED(status)) {
1117                                                 sp->status = -1;
1118                                                 jp->state = 0;
1119                                         } else
1120                                                 sp->status = status;
1121                                         thisjob = jp;
1122                                 }
1123                                 if (sp->status == -1)
1124                                         stopped = 0;
1125                                 else if (WIFSTOPPED(sp->status))
1126                                         done = 0;
1127                         }
1128                         if (stopped) {          /* stopped or done */
1129                                 int state = done? JOBDONE : JOBSTOPPED;
1130                                 if (jp->state != state) {
1131                                         TRACE(("Job %td: changing state from %d to %d\n", jp - jobtab + 1, jp->state, state));
1132                                         jp->state = state;
1133                                         if (jp != job) {
1134                                                 if (done && !jp->remembered &&
1135                                                     !iflag && jp != bgjob)
1136                                                         freejob(jp);
1137 #if JOBS
1138                                                 else if (done)
1139                                                         deljob(jp);
1140 #endif
1141                                         }
1142                                 }
1143                         }
1144                 }
1145         }
1146         INTON;
1147         if (!thisjob || thisjob->state == 0)
1148                 ;
1149         else if ((!rootshell || !iflag || thisjob == job) &&
1150             thisjob->foreground && thisjob->state != JOBSTOPPED) {
1151                 sig = 0;
1152                 coredump = 0;
1153                 for (sp = thisjob->ps; sp < thisjob->ps + thisjob->nprocs; sp++)
1154                         if (WIFSIGNALED(sp->status)) {
1155                                 sig = WTERMSIG(sp->status);
1156                                 coredump = WCOREDUMP(sp->status);
1157                         }
1158                 if (sig > 0 && sig != SIGINT && sig != SIGPIPE) {
1159                         sigstr = strsignal(sig);
1160                         if (sigstr != NULL)
1161                                 out2str(sigstr);
1162                         else
1163                                 out2str("Unknown signal");
1164                         if (coredump)
1165                                 out2str(" (core dumped)");
1166                         out2c('\n');
1167                         flushout(out2);
1168                 }
1169         } else {
1170                 TRACE(("Not printing status, rootshell=%d, job=%p\n", rootshell, job));
1171                 thisjob->changed = 1;
1172         }
1173         return pid;
1174 }
1175
1176
1177
1178 /*
1179  * return 1 if there are stopped jobs, otherwise 0
1180  */
1181 int job_warning = 0;
1182 int
1183 stoppedjobs(void)
1184 {
1185         int jobno;
1186         struct job *jp;
1187
1188         if (job_warning)
1189                 return (0);
1190         for (jobno = 1, jp = jobtab; jobno <= njobs; jobno++, jp++) {
1191                 if (jp->used == 0)
1192                         continue;
1193                 if (jp->state == JOBSTOPPED) {
1194                         out2fmt_flush("You have stopped jobs.\n");
1195                         job_warning = 2;
1196                         return (1);
1197                 }
1198         }
1199
1200         return (0);
1201 }
1202
1203
1204 static void
1205 checkzombies(void)
1206 {
1207         while (njobs > 0 && dowait(0, NULL) > 0)
1208                 ;
1209 }
1210
1211
1212 int
1213 backgndpidset(void)
1214 {
1215         return backgndpid != -1;
1216 }
1217
1218
1219 pid_t
1220 backgndpidval(void)
1221 {
1222         if (bgjob != NULL && !forcelocal)
1223                 bgjob->remembered = 1;
1224         return backgndpid;
1225 }
1226
1227 /*
1228  * Return a string identifying a command (to be printed by the
1229  * jobs command.
1230  */
1231
1232 static char *cmdnextc;
1233 static int cmdnleft;
1234 #define MAXCMDTEXT      200
1235
1236 char *
1237 commandtext(union node *n)
1238 {
1239         char *name;
1240
1241         cmdnextc = name = ckmalloc(MAXCMDTEXT);
1242         cmdnleft = MAXCMDTEXT - 4;
1243         cmdtxt(n);
1244         *cmdnextc = '\0';
1245         return name;
1246 }
1247
1248
1249 static void
1250 cmdtxt(union node *n)
1251 {
1252         union node *np;
1253         struct nodelist *lp;
1254         const char *p;
1255         int i;
1256         char s[2];
1257
1258         if (n == NULL)
1259                 return;
1260         switch (n->type) {
1261         case NSEMI:
1262                 cmdtxt(n->nbinary.ch1);
1263                 cmdputs("; ");
1264                 cmdtxt(n->nbinary.ch2);
1265                 break;
1266         case NAND:
1267                 cmdtxt(n->nbinary.ch1);
1268                 cmdputs(" && ");
1269                 cmdtxt(n->nbinary.ch2);
1270                 break;
1271         case NOR:
1272                 cmdtxt(n->nbinary.ch1);
1273                 cmdputs(" || ");
1274                 cmdtxt(n->nbinary.ch2);
1275                 break;
1276         case NPIPE:
1277                 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) {
1278                         cmdtxt(lp->n);
1279                         if (lp->next)
1280                                 cmdputs(" | ");
1281                 }
1282                 break;
1283         case NSUBSHELL:
1284                 cmdputs("(");
1285                 cmdtxt(n->nredir.n);
1286                 cmdputs(")");
1287                 break;
1288         case NREDIR:
1289         case NBACKGND:
1290                 cmdtxt(n->nredir.n);
1291                 break;
1292         case NIF:
1293                 cmdputs("if ");
1294                 cmdtxt(n->nif.test);
1295                 cmdputs("; then ");
1296                 cmdtxt(n->nif.ifpart);
1297                 cmdputs("...");
1298                 break;
1299         case NWHILE:
1300                 cmdputs("while ");
1301                 goto until;
1302         case NUNTIL:
1303                 cmdputs("until ");
1304 until:
1305                 cmdtxt(n->nbinary.ch1);
1306                 cmdputs("; do ");
1307                 cmdtxt(n->nbinary.ch2);
1308                 cmdputs("; done");
1309                 break;
1310         case NFOR:
1311                 cmdputs("for ");
1312                 cmdputs(n->nfor.var);
1313                 cmdputs(" in ...");
1314                 break;
1315         case NCASE:
1316                 cmdputs("case ");
1317                 cmdputs(n->ncase.expr->narg.text);
1318                 cmdputs(" in ...");
1319                 break;
1320         case NDEFUN:
1321                 cmdputs(n->narg.text);
1322                 cmdputs("() ...");
1323                 break;
1324         case NNOT:
1325                 cmdputs("! ");
1326                 cmdtxt(n->nnot.com);
1327                 break;
1328         case NCMD:
1329                 for (np = n->ncmd.args ; np ; np = np->narg.next) {
1330                         cmdtxt(np);
1331                         if (np->narg.next)
1332                                 cmdputs(" ");
1333                 }
1334                 for (np = n->ncmd.redirect ; np ; np = np->nfile.next) {
1335                         cmdputs(" ");
1336                         cmdtxt(np);
1337                 }
1338                 break;
1339         case NARG:
1340                 cmdputs(n->narg.text);
1341                 break;
1342         case NTO:
1343                 p = ">";  i = 1;  goto redir;
1344         case NAPPEND:
1345                 p = ">>";  i = 1;  goto redir;
1346         case NTOFD:
1347                 p = ">&";  i = 1;  goto redir;
1348         case NCLOBBER:
1349                 p = ">|"; i = 1; goto redir;
1350         case NFROM:
1351                 p = "<";  i = 0;  goto redir;
1352         case NFROMTO:
1353                 p = "<>";  i = 0;  goto redir;
1354         case NFROMFD:
1355                 p = "<&";  i = 0;  goto redir;
1356 redir:
1357                 if (n->nfile.fd != i) {
1358                         s[0] = n->nfile.fd + '0';
1359                         s[1] = '\0';
1360                         cmdputs(s);
1361                 }
1362                 cmdputs(p);
1363                 if (n->type == NTOFD || n->type == NFROMFD) {
1364                         if (n->ndup.dupfd >= 0)
1365                                 s[0] = n->ndup.dupfd + '0';
1366                         else
1367                                 s[0] = '-';
1368                         s[1] = '\0';
1369                         cmdputs(s);
1370                 } else {
1371                         cmdtxt(n->nfile.fname);
1372                 }
1373                 break;
1374         case NHERE:
1375         case NXHERE:
1376                 cmdputs("<<...");
1377                 break;
1378         default:
1379                 cmdputs("???");
1380                 break;
1381         }
1382 }
1383
1384
1385
1386 static void
1387 cmdputs(const char *s)
1388 {
1389         const char *p;
1390         char *q;
1391         char c;
1392         int subtype = 0;
1393
1394         if (cmdnleft <= 0)
1395                 return;
1396         p = s;
1397         q = cmdnextc;
1398         while ((c = *p++) != '\0') {
1399                 if (c == CTLESC)
1400                         *q++ = *p++;
1401                 else if (c == CTLVAR) {
1402                         *q++ = '$';
1403                         if (--cmdnleft > 0)
1404                                 *q++ = '{';
1405                         subtype = *p++;
1406                         if ((subtype & VSTYPE) == VSLENGTH && --cmdnleft > 0)
1407                                 *q++ = '#';
1408                 } else if (c == '=' && subtype != 0) {
1409                         *q = "}-+?=##%%\0X"[(subtype & VSTYPE) - VSNORMAL];
1410                         if (*q)
1411                                 q++;
1412                         else
1413                                 cmdnleft++;
1414                         if (((subtype & VSTYPE) == VSTRIMLEFTMAX ||
1415                             (subtype & VSTYPE) == VSTRIMRIGHTMAX) &&
1416                             --cmdnleft > 0)
1417                                 *q = q[-1], q++;
1418                         subtype = 0;
1419                 } else if (c == CTLENDVAR) {
1420                         *q++ = '}';
1421                 } else if (c == CTLBACKQ || c == CTLBACKQ+CTLQUOTE) {
1422                         cmdnleft -= 5;
1423                         if (cmdnleft > 0) {
1424                                 *q++ = '$';
1425                                 *q++ = '(';
1426                                 *q++ = '.';
1427                                 *q++ = '.';
1428                                 *q++ = '.';
1429                                 *q++ = ')';
1430                         }
1431                 } else if (c == CTLARI) {
1432                         cmdnleft -= 2;
1433                         if (cmdnleft > 0) {
1434                                 *q++ = '$';
1435                                 *q++ = '(';
1436                                 *q++ = '(';
1437                         }
1438                         p++;
1439                 } else if (c == CTLENDARI) {
1440                         if (--cmdnleft > 0) {
1441                                 *q++ = ')';
1442                                 *q++ = ')';
1443                         }
1444                 } else if (c == CTLQUOTEMARK || c == CTLQUOTEEND)
1445                         cmdnleft++; /* ignore */
1446                 else
1447                         *q++ = c;
1448                 if (--cmdnleft <= 0) {
1449                         *q++ = '.';
1450                         *q++ = '.';
1451                         *q++ = '.';
1452                         break;
1453                 }
1454         }
1455         cmdnextc = q;
1456 }