xref: /openbsd-src/usr.bin/make/engine.c (revision a28daedfc357b214be5c701aa8ba8adb29a7f1c2)
1 /*	$OpenBSD: engine.c,v 1.23 2009/04/26 09:25:49 espie Exp $ */
2 /*
3  * Copyright (c) 1988, 1989, 1990 The Regents of the University of California.
4  * Copyright (c) 1988, 1989 by Adam de Boor
5  * Copyright (c) 1989 by Berkeley Softworks
6  * All rights reserved.
7  *
8  * This code is derived from software contributed to Berkeley by
9  * Adam de Boor.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #include <sys/types.h>
37 #include <sys/wait.h>
38 #include <assert.h>
39 #include <limits.h>
40 #include <stdio.h>
41 #include <stdlib.h>
42 #include <ctype.h>
43 #include <errno.h>
44 #include <fcntl.h>
45 #include <unistd.h>
46 #include <string.h>
47 #include <signal.h>
48 #include "config.h"
49 #include "defines.h"
50 #include "dir.h"
51 #include "engine.h"
52 #include "arch.h"
53 #include "gnode.h"
54 #include "targ.h"
55 #include "var.h"
56 #include "extern.h"
57 #include "lst.h"
58 #include "timestamp.h"
59 #include "make.h"
60 #include "pathnames.h"
61 #include "error.h"
62 #include "str.h"
63 #include "memory.h"
64 #include "buf.h"
65 
66 static void MakeTimeStamp(void *, void *);
67 static int rewrite_time(const char *);
68 static void setup_signal(int);
69 static void setup_all_signals(void);
70 static void setup_meta(void);
71 static char **recheck_command_for_shell(char **);
72 
73 static int setup_and_run_command(char *, GNode *, int);
74 static void run_command(const char *, bool);
75 static int run_prepared_gnode(GNode *);
76 static void handle_compat_interrupts(GNode *);
77 
78 bool
79 Job_CheckCommands(GNode *gn)
80 {
81 	/* Alter our type to tell if errors should be ignored or things
82 	 * should not be printed so setup_and_run_command knows what to do.
83 	 */
84 	if (Targ_Ignore(gn))
85 		gn->type |= OP_IGNORE;
86 	if (Targ_Silent(gn))
87 		gn->type |= OP_SILENT;
88 
89 	if (OP_NOP(gn->type) && Lst_IsEmpty(&gn->commands) &&
90 	    (gn->type & OP_LIB) == 0) {
91 		/*
92 		 * No commands. Look for .DEFAULT rule from which we might infer
93 		 * commands
94 		 */
95 		if ((gn->type & OP_NODEFAULT) == 0 &&
96 		    (DEFAULT->type & OP_DUMMY) == 0 &&
97 		    !Lst_IsEmpty(&DEFAULT->commands)) {
98 			/*
99 			 * Make only looks for a .DEFAULT if the node was never
100 			 * the target of an operator, so that's what we do too.
101 			 * If a .DEFAULT was given, we substitute its commands
102 			 * for gn's commands and set the IMPSRC variable to be
103 			 * the target's name The DEFAULT node acts like a
104 			 * transformation rule, in that gn also inherits any
105 			 * attributes or sources attached to .DEFAULT itself.
106 			 */
107 			Make_HandleUse(DEFAULT, gn);
108 			Var(IMPSRC_INDEX, gn) = Var(TARGET_INDEX, gn);
109 		} else if (is_out_of_date(Dir_MTime(gn))) {
110 			/*
111 			 * The node wasn't the target of an operator we have no
112 			 * .DEFAULT rule to go on and the target doesn't
113 			 * already exist. There's nothing more we can do for
114 			 * this branch.
115 			 */
116 			 return false;
117 	    	}
118 	}
119 	return true;
120 }
121 
122 void
123 job_failure(GNode *gn, void (*abortProc)(char *, ...))
124 {
125 	/*
126 	 If the -k flag wasn't given, we stop in
127 	 * our tracks, otherwise we just don't update this
128 	 * node's parents so they never get examined.
129 	 */
130 	static const char msg[] =
131 	    "make: don't know how to make";
132 
133 	if (gn->type & OP_OPTIONAL) {
134 		(void)fprintf(stdout, "%s %s(ignored)\n", msg,
135 		    gn->name);
136 		(void)fflush(stdout);
137 	} else if (keepgoing) {
138 		(void)fprintf(stdout, "%s %s(continuing)\n",
139 		    msg, gn->name);
140 		(void)fflush(stdout);
141 	} else {
142 		(*abortProc)("%s %s. Stop in %s.", msg,
143 		    gn->name, Var_Value(".CURDIR"));
144 	}
145 }
146 /* touch files the hard way, by writing stuff to them */
147 static int
148 rewrite_time(const char *name)
149 {
150 	int fd;
151 	char c;
152 
153 	fd = open(name, O_RDWR | O_CREAT, 0666);
154 	if (fd < 0)
155 		return -1;
156 	/*
157 	 * Read and write a byte to the file to change
158 	 * the modification time.
159 	 */
160 	if (read(fd, &c, 1) == 1) {
161 		(void)lseek(fd, 0, SEEK_SET);
162 		(void)write(fd, &c, 1);
163 	}
164 
165 	(void)close(fd);
166 	return 0;
167 }
168 
169 void
170 Job_Touch(GNode *gn)
171 {
172 	if (gn->type & (OP_JOIN|OP_USE|OP_EXEC|OP_OPTIONAL)) {
173 		/*
174 		 * .JOIN, .USE, and .OPTIONAL targets are "virtual" targets
175 		 * and, as such, shouldn't really be created.
176 		 */
177 		return;
178 	}
179 
180 	if (!(gn->type & OP_SILENT)) {
181 		(void)fprintf(stdout, "touch %s\n", gn->name);
182 		(void)fflush(stdout);
183 	}
184 
185 	if (noExecute) {
186 		return;
187 	}
188 
189 	if (gn->type & OP_ARCHV) {
190 		Arch_Touch(gn);
191 	} else if (gn->type & OP_LIB) {
192 		Arch_TouchLib(gn);
193 	} else {
194 		const char *file = gn->path != NULL ? gn->path : gn->name;
195 
196 		if (set_times(file) == -1){
197 			if (rewrite_time(file) == -1) {
198 				(void)fprintf(stdout,
199 				    "*** couldn't touch %s: %s", file,
200 				    strerror(errno));
201 				(void)fflush(stdout);
202 		    	}
203 		}
204 	}
205 }
206 
207 void
208 Make_TimeStamp(GNode *parent, GNode *child)
209 {
210 	if (is_strictly_before(parent->cmtime, child->mtime))
211 		parent->cmtime = child->mtime;
212 }
213 
214 void
215 Make_HandleUse(GNode	*cgn,	/* The .USE node */
216     GNode	*pgn)	/* The target of the .USE node */
217 {
218 	GNode	*gn;	/* A child of the .USE node */
219 	LstNode	ln;	/* An element in the children list */
220 
221 
222 	assert(cgn->type & (OP_USE|OP_TRANSFORM));
223 
224 	if ((cgn->type & OP_USE) || Lst_IsEmpty(&pgn->commands)) {
225 		/* .USE or transformation and target has no commands
226 		 * -- append the child's commands to the parent.  */
227 		Lst_Concat(&pgn->commands, &cgn->commands);
228 	}
229 
230 	for (ln = Lst_First(&cgn->children); ln != NULL;
231 	    ln = Lst_Adv(ln)) {
232 		gn = (GNode *)Lst_Datum(ln);
233 
234 		if (Lst_AddNew(&pgn->children, gn)) {
235 			Lst_AtEnd(&gn->parents, pgn);
236 			pgn->unmade++;
237 		}
238 	}
239 
240 	pgn->type |= cgn->type & ~(OP_OPMASK|OP_USE|OP_TRANSFORM);
241 
242 	/*
243 	 * This child node is now "made", so we decrement the count of
244 	 * unmade children in the parent... We also remove the child
245 	 * from the parent's list to accurately reflect the number of
246 	 * decent children the parent has. This is used by Make_Run to
247 	 * decide whether to queue the parent or examine its children...
248 	 */
249 	if (cgn->type & OP_USE)
250 		pgn->unmade--;
251 
252 	/* if the parent node doesn't have any location, then inherit the
253 	 * use stuff, since that gives us better error messages.
254 	 */
255 	if (!pgn->lineno) {
256 		pgn->lineno = cgn->lineno;
257 		pgn->fname = cgn->fname;
258 	}
259 }
260 
261 void
262 Make_DoAllVar(GNode *gn)
263 {
264 	GNode *child;
265 	LstNode ln;
266 	BUFFER allsrc, oodate;
267 	char *target;
268 	bool do_oodate;
269 	int oodate_count, allsrc_count = 0;
270 
271 	oodate_count = 0;
272 	allsrc_count = 0;
273 
274 	for (ln = Lst_First(&gn->children); ln != NULL; ln = Lst_Adv(ln)) {
275 		child = (GNode *)Lst_Datum(ln);
276 		if ((child->type & (OP_EXEC|OP_USE|OP_INVISIBLE)) != 0)
277 			continue;
278 		if (OP_NOP(child->type) ||
279 		    (target = Var(TARGET_INDEX, child)) == NULL) {
280 			/*
281 			 * this node is only source; use the specific pathname
282 			 * for it
283 			 */
284 			target = child->path != NULL ? child->path :
285 			    child->name;
286 		}
287 
288 		/*
289 		 * It goes in the OODATE variable if the parent is younger than
290 		 * the child or if the child has been modified more recently
291 		 * than the start of the make.  This is to keep make from
292 		 * getting confused if something else updates the parent after
293 		 * the make starts (shouldn't happen, I know, but sometimes it
294 		 * does). In such a case, if we've updated the kid, the parent
295 		 * is likely to have a modification time later than that of the
296 		 * kid and anything that relies on the OODATE variable will be
297 		 * hosed.
298 		 */
299 		do_oodate = false;
300 		if (gn->type & OP_JOIN) {
301 			if (child->built_status == MADE)
302 				do_oodate = true;
303 		} else if (is_strictly_before(gn->mtime, child->mtime) ||
304 		   (!is_strictly_before(child->mtime, now) &&
305 		   child->built_status == MADE))
306 		   	do_oodate = true;
307 		if (do_oodate) {
308 			oodate_count++;
309 			if (oodate_count == 1)
310 				Var(OODATE_INDEX, gn) = target;
311 			else {
312 				if (oodate_count == 2) {
313 					Buf_Init(&oodate, 0);
314 					Buf_AddString(&oodate,
315 					    Var(OODATE_INDEX, gn));
316 				}
317 				Buf_AddSpace(&oodate);
318 				Buf_AddString(&oodate, target);
319 			}
320 		}
321 		allsrc_count++;
322 		if (allsrc_count == 1)
323 			Var(ALLSRC_INDEX, gn) = target;
324 		else {
325 			if (allsrc_count == 2) {
326 				Buf_Init(&allsrc, 0);
327 				Buf_AddString(&allsrc,
328 				    Var(ALLSRC_INDEX, gn));
329 			}
330 			Buf_AddSpace(&allsrc);
331 			Buf_AddString(&allsrc, target);
332 		}
333 	}
334 
335 	if (allsrc_count > 1)
336 		Var(ALLSRC_INDEX, gn) = Buf_Retrieve(&allsrc);
337 	if (oodate_count > 1)
338 		Var(OODATE_INDEX, gn) = Buf_Retrieve(&oodate);
339 
340 	if (gn->impliedsrc)
341 		Var(IMPSRC_INDEX, gn) = Var(TARGET_INDEX, gn->impliedsrc);
342 
343 	if (gn->type & OP_JOIN)
344 		Var(TARGET_INDEX, gn) = Var(ALLSRC_INDEX, gn);
345 }
346 
347 /* Wrapper to call Make_TimeStamp from a forEach loop.	*/
348 static void
349 MakeTimeStamp(void *parent, void *child)
350 {
351     Make_TimeStamp((GNode *)parent, (GNode *)child);
352 }
353 
354 bool
355 Make_OODate(GNode *gn)
356 {
357 	bool	    oodate;
358 
359 	/*
360 	 * Certain types of targets needn't even be sought as their datedness
361 	 * doesn't depend on their modification time...
362 	 */
363 	if ((gn->type & (OP_JOIN|OP_USE|OP_EXEC|OP_PHONY)) == 0) {
364 		(void)Dir_MTime(gn);
365 		if (DEBUG(MAKE)) {
366 			if (!is_out_of_date(gn->mtime))
367 				printf("modified %s...",
368 				    time_to_string(gn->mtime));
369 			else
370 				printf("non-existent...");
371 		}
372 	}
373 
374 	/*
375 	 * A target is remade in one of the following circumstances:
376 	 * - its modification time is smaller than that of its youngest child
377 	 *   and it would actually be run (has commands or type OP_NOP)
378 	 * - it's the object of a force operator
379 	 * - it has no children, was on the lhs of an operator and doesn't
380 	 *   exist already.
381 	 *
382 	 * Libraries are only considered out-of-date if the archive module says
383 	 * they are.
384 	 */
385 	if (gn->type & OP_USE) {
386 		/*
387 		 * If the node is a USE node it is *never* out of date
388 		 * no matter *what*.
389 		 */
390 		if (DEBUG(MAKE))
391 			printf(".USE node...");
392 		oodate = false;
393 	} else if ((gn->type & OP_LIB) && Arch_IsLib(gn)) {
394 		if (DEBUG(MAKE))
395 		    printf("library...");
396 
397 		/* always out of date if no children and :: target */
398 		oodate = Arch_LibOODate(gn) ||
399 		    (is_out_of_date(gn->cmtime) && (gn->type & OP_DOUBLEDEP));
400 	} else if (gn->type & OP_JOIN) {
401 		/*
402 		 * A target with the .JOIN attribute is only considered
403 		 * out-of-date if any of its children was out-of-date.
404 		 */
405 		if (DEBUG(MAKE))
406 			printf(".JOIN node...");
407 		oodate = gn->childMade;
408 	} else if (gn->type & (OP_FORCE|OP_EXEC|OP_PHONY)) {
409 		/*
410 		 * A node which is the object of the force (!) operator or which
411 		 * has the .EXEC attribute is always considered out-of-date.
412 		 */
413 		if (DEBUG(MAKE)) {
414 			if (gn->type & OP_FORCE)
415 				printf("! operator...");
416 			else if (gn->type & OP_PHONY)
417 				printf(".PHONY node...");
418 			else
419 				printf(".EXEC node...");
420 		}
421 		oodate = true;
422 	} else if (is_strictly_before(gn->mtime, gn->cmtime) ||
423 	   (is_out_of_date(gn->cmtime) &&
424 	    (is_out_of_date(gn->mtime) || (gn->type & OP_DOUBLEDEP)))) {
425 		/*
426 		 * A node whose modification time is less than that of its
427 		 * youngest child or that has no children (cmtime ==
428 		 * OUT_OF_DATE) and either doesn't exist (mtime == OUT_OF_DATE)
429 		 * or was the object of a :: operator is out-of-date.
430 		 */
431 		if (DEBUG(MAKE)) {
432 			if (is_strictly_before(gn->mtime, gn->cmtime))
433 				printf("modified before source...");
434 			else if (is_out_of_date(gn->mtime))
435 				printf("non-existent and no sources...");
436 			else
437 				printf(":: operator and no sources...");
438 		}
439 		oodate = true;
440 	} else {
441 		oodate = false;
442 	}
443 
444 	/*
445 	 * If the target isn't out-of-date, the parents need to know its
446 	 * modification time. Note that targets that appear to be out-of-date
447 	 * but aren't, because they have no commands and aren't of type OP_NOP,
448 	 * have their mtime stay below their children's mtime to keep parents
449 	 * from thinking they're out-of-date.
450 	 */
451 	if (!oodate)
452 		Lst_ForEach(&gn->parents, MakeTimeStamp, gn);
453 
454 	return oodate;
455 }
456 
457 volatile sig_atomic_t got_signal;
458 
459 volatile sig_atomic_t got_SIGINT, got_SIGHUP, got_SIGQUIT,
460     got_SIGTERM, got_SIGTSTP, got_SIGTTOU, got_SIGTTIN, got_SIGWINCH;
461 
462 static void
463 setup_signal(int sig)
464 {
465 	if (signal(sig, SIG_IGN) != SIG_IGN) {
466 		(void)signal(sig, SigHandler);
467 	}
468 }
469 
470 static void
471 setup_all_signals()
472 {
473 	/*
474 	 * Catch the four signals that POSIX specifies if they aren't ignored.
475 	 * handle_signal will take care of calling JobInterrupt if appropriate.
476 	 */
477 	setup_signal(SIGINT);
478 	setup_signal(SIGHUP);
479 	setup_signal(SIGQUIT);
480 	setup_signal(SIGTERM);
481 	/*
482 	 * There are additional signals that need to be caught and passed if
483 	 * either the export system wants to be told directly of signals or if
484 	 * we're giving each job its own process group (since then it won't get
485 	 * signals from the terminal driver as we own the terminal)
486 	 */
487 #if defined(USE_PGRP)
488 	setup_signal(SIGTSTP);
489 	setup_signal(SIGTTOU);
490 	setup_signal(SIGTTIN);
491 	setup_signal(SIGWINCH);
492 #endif
493 }
494 
495 void
496 SigHandler(int sig)
497 {
498 	switch(sig) {
499 	case SIGINT:
500 		got_SIGINT++;
501 		got_signal = 1;
502 		break;
503 	case SIGHUP:
504 		got_SIGHUP++;
505 		got_signal = 1;
506 		break;
507 	case SIGQUIT:
508 		got_SIGQUIT++;
509 		got_signal = 1;
510 		break;
511 	case SIGTERM:
512 		got_SIGTERM++;
513 		got_signal = 1;
514 		break;
515 #ifdef USE_PGRP
516 	case SIGTSTP:
517 		got_SIGTSTP++;
518 		got_signal = 1;
519 		break;
520 	case SIGTTOU:
521 		got_SIGTTOU++;
522 		got_signal = 1;
523 		break;
524 	case SIGTTIN:
525 		got_SIGTTIN++;
526 		got_signal = 1;
527 		break;
528 	case SIGWINCH:
529 		got_SIGWINCH++;
530 		got_signal = 1;
531 		break;
532 #endif
533 	}
534 }
535 
536 /* The following array is used to make a fast determination of which
537  * characters are interpreted specially by the shell.  If a command
538  * contains any of these characters, it is executed by the shell, not
539  * directly by us.  */
540 static char	    meta[256];
541 
542 void
543 setup_meta(void)
544 {
545 	char *p;
546 
547 	for (p = "#=|^(){};&<>*?[]:$`\\\n"; *p != '\0'; p++)
548 		meta[(unsigned char) *p] = 1;
549 	/* The null character serves as a sentinel in the string.  */
550 	meta[0] = 1;
551 }
552 
553 static char **
554 recheck_command_for_shell(char **av)
555 {
556 	char *runsh[] = {
557 		"alias", "cd", "eval", "exit", "read", "set", "ulimit",
558 		"unalias", "unset", "wait", "umask", NULL
559 	};
560 
561 	char **p;
562 
563 	/* optimization: if exec cmd, we avoid the intermediate shell */
564 	if (strcmp(av[0], "exec") == 0)
565 		av++;
566 
567 	for (p = runsh; *p; p++)
568 		if (strcmp(av[0], *p) == 0)
569 			return NULL;
570 
571 	return av;
572 }
573 
574 static void
575 run_command(const char *cmd, bool errCheck)
576 {
577 	const char *p;
578 	char *shargv[4];
579 	char **todo;
580 
581 	shargv[0] = _PATH_BSHELL;
582 
583 	shargv[1] = errCheck ? "-ec" : "-c";
584 	shargv[2] = (char *)cmd;
585 	shargv[3] = NULL;
586 
587 	todo = shargv;
588 
589 
590 	/* Search for meta characters in the command. If there are no meta
591 	 * characters, there's no need to execute a shell to execute the
592 	 * command.  */
593 	for (p = cmd; !meta[(unsigned char)*p]; p++)
594 		continue;
595 	if (*p == '\0') {
596 		char *bp;
597 		char **av;
598 		int argc;
599 		/* No meta-characters, so probably no need to exec a shell.
600 		 * Break the command into words to form an argument vector
601 		 * we can execute.  */
602 		av = brk_string(cmd, &argc, &bp);
603 		av = recheck_command_for_shell(av);
604 		if (av != NULL)
605 			todo = av;
606 	}
607 	execvp(todo[0], todo);
608 
609 	if (errno == ENOENT)
610 		fprintf(stderr, "%s: not found\n", todo[0]);
611 	else
612 		perror(todo[0]);
613 	_exit(1);
614 }
615 
616 /*-
617  *-----------------------------------------------------------------------
618  * setup_and_run_command --
619  *	Execute the next command for a target. If the command returns an
620  *	error, the node's built_status field is set to ERROR and creation stops.
621  *
622  * Results:
623  *	0 in case of error, 1 if ok.
624  *
625  * Side Effects:
626  *	The node's 'built_status' field may be set to ERROR.
627  *-----------------------------------------------------------------------
628  */
629 static int
630 setup_and_run_command(char *cmd, GNode *gn, int dont_fork)
631 {
632 	bool silent;	/* Don't print command */
633 	bool doExecute;	/* Execute the command */
634 	bool errCheck;	/* Check errors */
635 	int reason;	/* Reason for child's death */
636 	int status;	/* Description of child's death */
637 	pid_t cpid; 	/* Child actually found */
638 	pid_t stat;	/* Status of fork */
639 
640 	silent = gn->type & OP_SILENT;
641 	errCheck = !(gn->type & OP_IGNORE);
642 	doExecute = !noExecute;
643 
644 	/* How can we execute a null command ? we warn the user that the
645 	 * command expanded to nothing (is this the right thing to do?).  */
646 	if (*cmd == '\0') {
647 		Error("%s expands to empty string", cmd);
648 		return 1;
649 	}
650 
651 	for (;; cmd++) {
652 		if (*cmd == '@')
653 			silent = DEBUG(LOUD) ? false : true;
654 		else if (*cmd == '-')
655 			errCheck = false;
656 		else if (*cmd == '+')
657 			doExecute = true;
658 		else
659 			break;
660 	}
661 	while (isspace(*cmd))
662 		cmd++;
663 	/* Print the command before echoing if we're not supposed to be quiet
664 	 * for this one. We also print the command if -n given.  */
665 	if (!silent || noExecute) {
666 		printf("%s\n", cmd);
667 		fflush(stdout);
668 	}
669 	/* If we're not supposed to execute any commands, this is as far as
670 	 * we go...  */
671 	if (!doExecute)
672 		return 1;
673 
674 	/* if we're running in parallel mode, we try not to fork the last
675 	 * command, since it's exit status will be just fine... unless
676 	 * errCheck is not set, in which case we must deal with the
677 	 * status ourselves.
678 	 */
679 	if (dont_fork && errCheck)
680 		run_command(cmd, errCheck);
681 		/*NOTREACHED*/
682 
683 	/* Fork and execute the single command. If the fork fails, we abort.  */
684 	switch (cpid = fork()) {
685 	case -1:
686 		Fatal("Could not fork");
687 		/*NOTREACHED*/
688 	case 0:
689 		run_command(cmd, errCheck);
690 		/*NOTREACHED*/
691 	default:
692 		break;
693 	}
694 
695 	/* The child is off and running. Now all we can do is wait...  */
696 	while (1) {
697 
698 		while ((stat = wait(&reason)) != cpid) {
699 			if (stat == -1 && errno != EINTR)
700 				break;
701 		}
702 
703 		if (got_signal)
704 			break;
705 
706 		if (stat != -1) {
707 			if (WIFSTOPPED(reason))
708 				status = WSTOPSIG(reason);	/* stopped */
709 			else if (WIFEXITED(reason)) {
710 				status = WEXITSTATUS(reason);	/* exited */
711 				if (status != 0)
712 				    printf("*** Error code %d", status);
713 			} else {
714 				status = WTERMSIG(reason);	/* signaled */
715 				printf("*** Signal %d", status);
716 			}
717 
718 
719 			if (!WIFEXITED(reason) || status != 0) {
720 				if (errCheck) {
721 					gn->built_status = ERROR;
722 					if (keepgoing)
723 						/* Abort the current target,
724 						 * but let others continue.  */
725 						printf(" (continuing)\n");
726 				} else {
727 					/* Continue executing commands for
728 					 * this target.  If we return 0,
729 					 * this will happen...  */
730 					printf(" (ignored)\n");
731 					status = 0;
732 				}
733 			}
734 			return !status;
735 		} else
736 			Fatal("error in wait: %d", stat);
737 			/*NOTREACHED*/
738 	}
739 	return 0;
740 }
741 
742 static void
743 handle_compat_interrupts(GNode *gn)
744 {
745 	if (!Targ_Precious(gn)) {
746 		char *file = Var(TARGET_INDEX, gn);
747 
748 		if (!noExecute && eunlink(file) != -1)
749 			Error("*** %s removed\n", file);
750 	}
751 	if (got_SIGINT) {
752 		signal(SIGINT, SIG_IGN);
753 		signal(SIGTERM, SIG_IGN);
754 		signal(SIGHUP, SIG_IGN);
755 		signal(SIGQUIT, SIG_IGN);
756 		got_signal = 0;
757 		got_SIGINT = 0;
758 		run_gnode(interrupt_node);
759 		exit(255);
760 	}
761 	exit(255);
762 }
763 
764 void
765 expand_commands(GNode *gn)
766 {
767 	LstNode ln;
768 	char *cmd;
769 
770 	for (ln = Lst_First(&gn->commands); ln != NULL; ln = Lst_Adv(ln)) {
771 		cmd = Var_Subst(Lst_Datum(ln), &gn->context, false);
772 		Lst_AtEnd(&gn->expanded, cmd);
773 	}
774 }
775 
776 int
777 run_gnode(GNode *gn)
778 {
779 	if (gn != NULL && (gn->type & OP_DUMMY) == 0) {
780 		expand_commands(gn);
781 		return run_prepared_gnode(gn);
782 	} else {
783 		return NOSUCHNODE;
784 	}
785 }
786 
787 static int
788 run_prepared_gnode(GNode *gn)
789 {
790 	char *cmd;
791 
792 	gn->built_status = MADE;
793 	while ((cmd = Lst_DeQueue(&gn->expanded)) != NULL) {
794 		if (setup_and_run_command(cmd, gn, 0) == 0)
795 			break;
796 		free(cmd);
797 	}
798 	free(cmd);
799 	if (got_signal)
800 		handle_compat_interrupts(gn);
801 	return gn->built_status;
802 }
803 
804 void
805 run_gnode_parallel(GNode *gn)
806 {
807 	char *cmd;
808 
809 	gn->built_status = MADE;
810 	/* XXX don't bother freeing cmd, we're dead anyways ! */
811 	while ((cmd = Lst_DeQueue(&gn->expanded)) != NULL) {
812 		if (setup_and_run_command(cmd, gn,
813 		    Lst_IsEmpty(&gn->expanded)) == 0)
814 			break;
815 	}
816 	/* Normally, we don't reach this point, unless the last command
817 	 * ignores error, in which case we interpret the status ourselves.
818 	 */
819 	switch(gn->built_status) {
820 	case MADE:
821 		exit(0);
822 	case ERROR:
823 		exit(1);
824 	default:
825 		fprintf(stderr,
826 		    "Could not run gnode, returned %d\n",
827 			gn->built_status);
828 		exit(1);
829 	}
830 }
831 
832 void
833 setup_engine()
834 {
835 	static int already_setup = 0;
836 
837 	if (!already_setup) {
838 		setup_meta();
839 		setup_all_signals();
840 		already_setup = 1;
841 	}
842 }
843