#include	"mk.h" typedef struct Event{	int pid;	Job *job;} Event;static Event *events;static int nevents, nrunning, nproclimit; typedef struct Process{	int pid;	int status;	struct Process *b, *f;} Process;static Process *phead, *pfree;static void sched(void);static void pnew(int, int), pdelete(Process *); int pidslot(int); voidrun(Job *j){	Job *jj; 	if(jobs){		for(jj = jobs; jj->next; jj = jj->next)			;		jj->next = j;	} else 		jobs = j;	j->next = 0;	/* this code also in waitup after parse redirect */	if(nrunning < nproclimit)		sched();} static voidsched(void){	char *flags;	Job *j;	Bufblock *buf;	int slot;	Node *n;	Envy *e; 	if(jobs == 0){		usage();		return;	}	j = jobs;	jobs = j->next;	if(DEBUG(D_EXEC))		fprint(1, "firing up job for target %s\n", wtos(j->t, ' '));	slot = nextslot();	events[slot].job = j;	buf = newbuf();	e = buildenv(j, slot);	shprint(j->r->recipe, e, buf);	if(!tflag && (nflag || !(j->r->attr&QUIET)))		Bwrite(&bout, buf->start, (long)strlen(buf->start));	freebuf(buf);	if(nflag||tflag){		for(n = j->n; n; n = n->next){			if(tflag){				if(!(n->flags&VIRTUAL))					touch(n->name);				else if(explain)					Bprint(&bout, "no touch of virtual '%s'\n", n->name);			}			n->time = time((long *)0);			MADESET(n, MADE);		}	} else {		if(DEBUG(D_EXEC))			fprint(1, "recipe='%s'", j->r->recipe);/**/		Bflush(&bout);		if(j->r->attr&NOMINUSE)			flags = 0;		else			flags = "-e";		events[slot].pid = execsh(flags, j->r->recipe, 0, e);		usage();		nrunning++;		if(DEBUG(D_EXEC))			fprint(1, "pid for target %s = %d\n", wtos(j->t, ' '), events[slot].pid);	}} intwaitup(int echildok, int *retstatus){	Envy *e;	int pid;	int slot;	Symtab *s;	Word *w;	Job *j;	char buf[ERRMAX];	Bufblock *bp;	int uarg = 0;	int done;	Node *n;	Process *p;	extern int runerrs; 	/* first check against the proces slist */	if(retstatus)		for(p = phead; p; p = p->f)			if(p->pid == *retstatus){				*retstatus = p->status;				pdelete(p);				return(-1);			}again:		/* rogue processes */	pid = waitfor(buf);	if(pid == -1){		if(echildok > 0)			return(1);		else {			fprint(2, "mk: (waitup %d) ", echildok);			perror("mk wait");			Exit();		}	}	if(DEBUG(D_EXEC))		fprint(1, "waitup got pid=%d, status='%s'\n", pid, buf);	if(retstatus && pid == *retstatus){		*retstatus = buf[0]? 1:0;		return(-1);	}	slot = pidslot(pid);	if(slot < 0){		if(DEBUG(D_EXEC))			fprint(2, "mk: wait returned unexpected process %d\n", pid);		pnew(pid, buf[0]? 1:0);		goto again;	}	j = events[slot].job;	usage();	nrunning--;	events[slot].pid = -1;	if(buf[0]){		e = buildenv(j, slot);		bp = newbuf();		shprint(j->r->recipe, e, bp);		front(bp->start);		fprint(2, "mk: %s: exit status=%s", bp->start, buf);		freebuf(bp);		for(n = j->n, done = 0; n; n = n->next)			if(n->flags&DELETE){				if(done++ == 0)					fprint(2, ", deleting");				fprint(2, " '%s'", n->name);				delete(n->name);			}		fprint(2, "\n");		if(kflag){			runerrs++;			uarg = 1;		} else {			jobs = 0;			Exit();		}	}	for(w = j->t; w; w = w->next){		if((s = symlook(w->s, S_NODE, 0)) == 0)			continue;	/* not interested in this node */		update(uarg, (Node *)s->value);	}	if(nrunning < nproclimit)		sched();	return(0);} voidnproc(void){	Symtab *sym;	Word *w; 	if(sym = symlook("NPROC", S_VAR, 0)) {		w = (Word *) sym->value;		if (w && w->s && w->s[0])			nproclimit = atoi(w->s);	}	if(nproclimit < 1)		nproclimit = 1;	if(DEBUG(D_EXEC))		fprint(1, "nprocs = %d\n", nproclimit);	if(nproclimit > nevents){		if(nevents)			events = (Event *)Realloc((char *)events, nproclimit*sizeof(Event));		else			events = (Event *)Malloc(nproclimit*sizeof(Event));		while(nevents < nproclimit)			events[nevents++].pid = 0;	}} intnextslot(void){	int i; 	for(i = 0; i < nproclimit; i++)		if(events[i].pid <= 0) return i;	assert("out of slots!!", 0);	return 0;	/* cyntax */} intpidslot(int pid){	int i; 	for(i = 0; i < nevents; i++)		if(events[i].pid == pid) return(i);	if(DEBUG(D_EXEC))		fprint(2, "mk: wait returned unexpected process %d\n", pid);	return(-1);}  static voidpnew(int pid, int status){	Process *p; 	if(pfree){		p = pfree;		pfree = p->f;	} else		p = (Process *)Malloc(sizeof(Process));	p->pid = pid;	p->status = status;	p->f = phead;	phead = p;	if(p->f)		p->f->b = p;	p->b = 0;} static voidpdelete(Process *p){	if(p->f)		p->f->b = p->b;	if(p->b)		p->b->f = p->f;	else		phead = p->f;	p->f = pfree;	pfree = p;} voidkillchildren(char *msg){	Process *p; 	kflag = 1;	/* to make sure waitup doesn't exit */	jobs = 0;	/* make sure no more get scheduled */	for(p = phead; p; p = p->f)		expunge(p->pid, msg);	while(waitup(1, (int *)0) == 0)		;	Bprint(&bout, "mk: %s\n", msg);	Exit();} static long tslot[1000];static long tick; voidusage(void){	long t; 	time(&t);	if(tick)		tslot[nrunning] += (t-tick);	tick = t;} voidprusage(void){	int i; 	usage();	for(i = 0; i <= nevents; i++)		fprint(1, "%d: %ld\n", i, tslot[i]);}