/*  * This file is part of the UCB release of Plan 9. It is subject to the license * terms in the LICENSE file found in the top-level directory of this * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No * part of the UCB release of Plan 9, including this file, may be copied, * modified, propagated, or distributed except according to the terms contained * in the LICENSE file. */ #include <u.h>#include <libc.h>#include <bio.h>#include <libsec.h>#include <auth.h>#include "authcmdlib.h" char CRONLOG[] = "cron"; enum {	Minute = 60,	Hour = 60 * Minute,	Day = 24 * Hour,}; typedef struct Job	Job;typedef struct Time	Time;typedef struct User	User; struct Time{			/* bit masks for each valid time */	uvlong	min;	ulong	hour;	ulong	mday;	ulong	wday;	ulong	mon;}; struct Job{	char	*host;		/* where ... */	Time	time;			/* when ... */	char	*cmd;			/* and what to execute */	Job	*next;}; struct User{	Qid	lastqid;			/* of last read /cron/user/cron */	char	*name;			/* who ... */	Job	*jobs;			/* wants to execute these jobs */}; User	*users;int	nuser;int	maxuser;char	*savec;char	*savetok;int	tok;int	debug;ulong	lexval; void	rexec(User*, Job*);void	readalljobs(void);Job	*readjobs(char*, User*);int	getname(char**);uvlong	gettime(int, int);int	gettok(int, int);void	initcap(void);void	pushtok(void);void	usage(void);void	freejobs(Job*);User	*newuser(char*);void	*emalloc(ulong);void	*erealloc(void*, ulong);int	myauth(int, char*);void	createuser(void);int	mkcmd(char*, char*, int);void	printjobs(void);int	qidcmp(Qid, Qid);int	becomeuser(char*); ulongminute(ulong tm){	return tm - tm%Minute;		/* round down to the minute */} intsleepuntil(ulong tm){	ulong now = time(0);		if (now < tm)		return sleep((tm - now)*1000);	else		return 0;} #pragma varargck	argpos clog 1#pragma varargck	argpos fatal 1 static voidclog(char *fmt, ...){	char msg[256];	va_list arg; 	va_start(arg, fmt);	vseprint(msg, msg + sizeof msg, fmt, arg);	va_end(arg);	syslog(0, CRONLOG, msg);} static voidfatal(char *fmt, ...){	char msg[256];	va_list arg; 	va_start(arg, fmt);	vseprint(msg, msg + sizeof msg, fmt, arg);	va_end(arg);	clog("%s", msg);	error("%s", msg);} static intopenlock(char *file){	return create(file, ORDWR, 0600);} static intmklock(char *file){	int fd, try;	Dir *dir; 	fd = openlock(file);	if (fd >= 0) {		/* make it a lock file if it wasn't */		dir = dirfstat(fd);		if (dir == nil)			error("%s vanished: %r", file);		dir->mode |= DMEXCL;		dir->qid.type |= QTEXCL;		dirfwstat(fd, dir);		free(dir); 		/* reopen in case it wasn't a lock file at last open */		close(fd);	}	for (try = 0; try < 65 && (fd = openlock(file)) < 0; try++)		sleep(10*1000);	return fd;} voidmain(int argc, char *argv[]){	Job *j;	Tm tm;	Time t;	ulong now, last;		/* in seconds */	int i, lock; 	debug = 0;	ARGBEGIN{	case 'c':		createuser();		exits(0);	case 'd':		debug = 1;		break;	default:		usage();	}ARGEND 	if(debug){		readalljobs();		printjobs();		exits(0);	} 	initcap();		/* do this early, before cpurc removes it */ 	switch(fork()){	case -1:		fatal("can't fork: %r");	case 0:		break;	default:		exits(0);	} 	/*	 * it can take a few minutes before the file server notices that	 * we've rebooted and gives up the lock.	 */	lock = mklock("/cron/lock");	if (lock < 0)		fatal("cron already running: %r"); 	argv0 = "cron";	srand(getpid()*time(0));	last = time(0);	for(;;){		readalljobs();		/*		 * the system's notion of time may have jumped forward or		 * backward an arbitrary amount since the last call to time().		 */		now = time(0);		/*		 * if time has jumped backward, just note it and adapt.		 * if time has jumped forward more than a day,		 * just execute one day's jobs.		 */		if (now < last) {			clog("time went backward");			last = now;		} else if (now - last > Day) {			clog("time advanced more than a day");			last = now - Day;		}		now = minute(now);		for(last = minute(last); last <= now; last += Minute){			tm = *localtime(last);			t.min = 1ULL << tm.min;			t.hour = 1 << tm.hour;			t.wday = 1 << tm.wday;			t.mday = 1 << tm.mday;			t.mon =  1 << (tm.mon + 1);			for(i = 0; i < nuser; i++)				for(j = users[i].jobs; j; j = j->next)					if(j->time.min & t.min					&& j->time.hour & t.hour					&& j->time.wday & t.wday					&& j->time.mday & t.mday					&& j->time.mon & t.mon)						rexec(&users[i], j);		}		seek(lock, 0, 0);		write(lock, "x", 1);	/* keep the lock alive */		/*		 * if we're not at next minute yet, sleep until a second past		 * (to allow for sleep intervals being approximate),		 * which synchronises with minute roll-over as a side-effect.		 */		sleepuntil(now + Minute + 1);	}	/* not reached */} voidcreateuser(void){	Dir d;	char file[128], *user;	int fd; 	user = getuser();	snprint(file, sizeof file, "/cron/%s", user);	fd = create(file, OREAD, 0755|DMDIR);	if(fd < 0)		fatal("couldn't create %s: %r", file);	nulldir(&d);	d.gid = user;	dirfwstat(fd, &d);	close(fd);	snprint(file, sizeof file, "/cron/%s/cron", user);	fd = create(file, OREAD, 0644);	if(fd < 0)		fatal("couldn't create %s: %r", file);	nulldir(&d);	d.gid = user;	dirfwstat(fd, &d);	close(fd);} voidreadalljobs(void){	User *u;	Dir *d, *du;	char file[128];	int i, n, fd; 	fd = open("/cron", OREAD);	if(fd < 0)		fatal("can't open /cron: %r");	while((n = dirread(fd, &d)) > 0){		for(i = 0; i < n; i++){			if(strcmp(d[i].name, "log") == 0 ||			    !(d[i].qid.type & QTDIR))				continue;			if(strcmp(d[i].name, d[i].uid) != 0){				syslog(1, CRONLOG, "cron for %s owned by %s",					d[i].name, d[i].uid);				continue;			}			u = newuser(d[i].name);			snprint(file, sizeof file, "/cron/%s/cron", d[i].name);			du = dirstat(file);			if(du == nil || qidcmp(u->lastqid, du->qid) != 0){				freejobs(u->jobs);				u->jobs = readjobs(file, u);			}			free(du);		}		free(d);	}	close(fd);} /* * parse user's cron file * other lines: minute hour monthday month weekday host command */Job *readjobs(char *file, User *user){	Biobuf *b;	Job *j, *jobs;	Dir *d;	int line; 	d = dirstat(file);	if(!d)		return nil;	b = Bopen(file, OREAD);	if(!b){		free(d);		return nil;	}	jobs = nil;	user->lastqid = d->qid;	free(d);	for(line = 1; savec = Brdline(b, '\n'); line++){		savec[Blinelen(b) - 1] = '\0';		while(*savec == ' ' || *savec == '\t')			savec++;		if(*savec == '#' || *savec == '\0')			continue;		if(strlen(savec) > 1024){			clog("%s: line %d: line too long", user->name, line);			continue;		}		j = emalloc(sizeof *j);		j->time.min = gettime(0, 59);		if(j->time.min && (j->time.hour = gettime(0, 23))		&& (j->time.mday = gettime(1, 31))		&& (j->time.mon = gettime(1, 12))		&& (j->time.wday = gettime(0, 6))		&& getname(&j->host)){			j->cmd = emalloc(strlen(savec) + 1);			strcpy(j->cmd, savec);			j->next = jobs;			jobs = j;		}else{			clog("%s: line %d: syntax error", user->name, line);			free(j);		}	}	Bterm(b);	return jobs;} voidprintjobs(void){	char buf[8*1024];	Job *j;	int i; 	for(i = 0; i < nuser; i++){		print("user %s\n", users[i].name);		for(j = users[i].jobs; j; j = j->next)			if(!mkcmd(j->cmd, buf, sizeof buf))				print("\tbad job %s on host %s\n",					j->cmd, j->host);			else				print("\tjob %s on host %s\n", buf, j->host);	}} User *newuser(char *name){	int i; 	for(i = 0; i < nuser; i++)		if(strcmp(users[i].name, name) == 0)			return &users[i];	if(nuser == maxuser){		maxuser += 32;		users = erealloc(users, maxuser * sizeof *users);	}	memset(&users[nuser], 0, sizeof(users[nuser]));	users[nuser].name = strdup(name);	users[nuser].jobs = 0;	users[nuser].lastqid.type = QTFILE;	users[nuser].lastqid.path = ~0LL;	users[nuser].lastqid.vers = ~0L;	return &users[nuser++];} voidfreejobs(Job *j){	Job *next; 	for(; j; j = next){		next = j->next;		free(j->cmd);		free(j->host);		free(j);	}} intgetname(char **namep){	int c;	char buf[64], *p; 	if(!savec)		return 0;	while(*savec == ' ' || *savec == '\t')		savec++;	for(p = buf; (c = *savec) && c != ' ' && c != '\t'; p++){		if(p >= buf+sizeof buf -1)			return 0;		*p = *savec++;	}	*p = '\0';	*namep = strdup(buf);	if(*namep == 0){		clog("internal error: strdup failure");		_exits(0);	}	while(*savec == ' ' || *savec == '\t')		savec++;	return p > buf;} /* * return the next time range (as a bit vector) in the file: * times: '*' * 	| range * range: number *	| number '-' number *	| range ',' range * a return of zero means a syntax error was discovered */uvlonggettime(int min, int max){	uvlong n, m, e; 	if(gettok(min, max) == '*')		return ~0ULL;	n = 0;	while(tok == '1'){		m = 1ULL << lexval;		n |= m;		if(gettok(0, 0) == '-'){			if(gettok(lexval, max) != '1')				return 0;			e = 1ULL << lexval;			for( ; m <= e; m <<= 1)				n |= m;			gettok(min, max);		}		if(tok != ',')			break;		if(gettok(min, max) != '1')			return 0;	}	pushtok();	return n;} voidpushtok(void){	savec = savetok;} intgettok(int min, int max){	char c; 	savetok = savec;	if(!savec)		return tok = 0;	while((c = *savec) == ' ' || c == '\t')		savec++;	switch(c){	case '0': case '1': case '2': case '3': case '4':	case '5': case '6': case '7': case '8': case '9':		lexval = strtoul(savec, &savec, 10);

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