#include <u.h>#include <libc.h>#include <bio.h>#include <authsrv.h>#include "authcmdlib.h" char CRONLOG[] = "cron"; typedef struct Job	Job;typedef struct Time	Time;typedef struct User	User; struct Time{			/* bit masks for each valid time */	ulong	min;			/* actually 1 bit for every 2 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**);ulong	gettime(int, int);int	gettok(int, int);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); voidmain(int argc, char *argv[]){	Job *j;	Tm tm;	Time t;	ulong now, last, x;	int i; 	debug = 0;	ARGBEGIN{	case 'c':		createuser();		exits(0);	case 'd':		debug = 1;		break;	default:		usage();	}ARGEND	USED(argc, argv); 	if(debug){		readalljobs();		printjobs();		exits(0);	} 	switch(fork()){	case -1:		error("can't fork");	case 0:		break;	default:		exits(0);	} 	argv0 = "cron";	srand(getpid()*time(0));	last = time(0) / 60;	for(;;){		readalljobs();		now = time(0) / 60;		for(; last <= now; last += 2){			tm = *localtime(last*60);			t.min = 1 << tm.min/2;			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);		}		x = time(0) / 60;		if(x - now < 2)			sleep((2 - (x - now))*60*1000);	}	exits(0);} voidcreateuser(void){	Dir d;	char file[128], *user;	int fd; 	user = getuser();	sprint(file, "/cron/%s", user);	fd = create(file, OREAD, 0755|DMDIR);	if(fd < 0){		fprint(2, "couldn't create %s: %r\n", file);		exits("create");	}	nulldir(&d);	d.gid = user;	dirfwstat(fd, &d);	close(fd);	sprint(file, "/cron/%s/cron", user);	fd = create(file, OREAD, 0644);	if(fd < 0){		fprint(2, "couldn't create %s: %r\n", file);		exits("create");	}	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)		error("can't open /cron\n");	while((n = dirread(fd, &d)) > 0){		for(i = 0; i < n; i++){			if(strcmp(d[i].name, "log") == 0)				continue;			if(strcmp(d[i].name, d[i].uid) != 0){				syslog(1, CRONLOG, "cron for %s owned by %s\n", d[i].name, d[i].uid);				continue;			}			u = newuser(d[i].name);			sprint(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){			syslog(0, CRONLOG, "%s: line %d: line too long", user->name, line);			continue;		}		j = emalloc(sizeof *j);		if((j->time.min = gettime(0, 59))		&& (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{			syslog(0, CRONLOG, "%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){		syslog(0, CRONLOG, "internal error: strdup failure");		_exits(0);	}	while(*savec == ' ' || *savec == '\t')		savec++;	return p > buf;} /* * return the next time range in the file: * times: '*' * 	| range * range: number *	| number '-' number *	| range ',' range * a return of zero means a syntax error was discovered */ulonggettime(int min, int max){	ulong n, m, e; 	if(gettok(min, max) == '*')		return ~0;	n = 0;	while(tok == '1'){		m = 1 << lexval;		n |= m;		if(gettok(0, 0) == '-'){			if(gettok(lexval, max) != '1')				return 0;			e = 1 << 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);		if(lexval < min || lexval > max)			return tok = 0;		if(max > 32)			lexval /= 2;			/* yuk: correct min by / 2 */		return tok = '1';	case '*': case '-': case ',':		savec++;		return tok = c;	default:		return tok = 0;	}} intcall(char *host){	char *na, *p; 	na = netmkaddr(host, 0, "rexexec");	p = utfrune(na, L'!');	if(!p)		return -1;	p = utfrune(p+1, L'!');	if(!p)		return -1;	if(strcmp(p, "!rexexec") != 0)		return -2;	return dial(na, 0, 0, 0);} /* * convert command to run properly on the remote machine * need to escape the quotes wo they don't get stripped */intmkcmd(char *cmd, char *buf, int len){	char *p;	int n, m; 	n = sizeof "exec rc -c '" -1;	if(n >= len)		return 0;	strcpy(buf, "exec rc -c '");	while(p = utfrune(cmd, L'\'')){		p++;		m = p - cmd;		if(n + m + 1 >= len)			return 0;		strncpy(&buf[n], cmd, m);		n += m;		buf[n++] = '\'';		cmd = p;	}	m = strlen(cmd);	if(n + m + sizeof "'</dev/null>/dev/null>[2=1]" >= len)		return 0;	strcpy(&buf[n], cmd);	strcpy(&buf[n+m], "'</dev/null>/dev/null>[2=1]");	return 1;} voidrexec(User *user, Job *j){	char buf[8*1024], key[DESKEYLEN];	int n, fd; 	switch(rfork(RFPROC|RFNOWAIT|RFNAMEG|RFENVG|RFFDG)){	case 0:		break;	case -1:		syslog(0, CRONLOG, "can't fork a job for %s: %r\n", user->name);	default:		return;	}	if(findkey(KEYDB, user->name, key) == 0){		syslog(0, CRONLOG, "%s: key not found", user->name);		_exits(0);	} 	if(!mkcmd(j->cmd, buf, sizeof buf)){		syslog(0, CRONLOG, "internal error: cmd buffer overflow");		_exits(0);	} 	/*	 * remote call, auth, cmd with no i/o	 * give it 2 min to complete	 */	alarm(2*60*1000);	fd = call(j->host);	if(fd < 0){		if(fd == -2){			syslog(0, AUTHLOG, "%s: dangerous host %s", user->name, j->host);			syslog(0, CRONLOG, "%s: dangerous host %s", user->name, j->host);		}		syslog(0, CRONLOG, "%s: can't call %s: %r", user->name, j->host);		_exits(0);	}syslog(0, CRONLOG, "%s: called %s on %s", user->name, j->cmd, j->host);	if(myauth(fd, user->name) < 0){		syslog(0, CRONLOG, "%s: can't auth %s on %s: %r", user->name, j->cmd, j->host);		_exits(0);	}syslog(0, CRONLOG, "%s: authenticated %s on %s", user->name, j->cmd, j->host);	write(fd, buf, strlen(buf)+1);	write(fd, buf, 0);	while((n = read(fd, buf, sizeof(buf)-1)) > 0){		buf[n] = 0;		syslog(0, CRONLOG, "%s: %s\n", j->cmd, buf);	}	_exits(0);} void *emalloc(ulong n){	void *p; 	if(p = mallocz(n, 1))		return p;	error("out of memory");	return 0;

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