/* * cpu.c - Make a connection to a cpu server * *	   Invoked by listen as 'cpu -R | -L service net netdir' *	    	   by users  as 'cpu [-p] [-h system] [-c cmd args ...]' */ #include <u.h>#include <libc.h>#include <bio.h>#include <auth.h> void	remoteside(void);void	fatal(int, char*, ...);void	noteproc(char*);void	catcher(void*, char*);void	remotenote(void);void	usage(void);void	writestr(int, char*, char*, int);void	readstr(int, char*, int, char*);char	*rexcall(int*, char*, char*); int 	notechan;char	system[32];int	cflag;int	hflag; char	*srvname = "cpu";char	*notesrv = "cpunote";char	*exportfs = "/bin/exportfs"; voidmain(int argc, char **argv){	char dat[128], buf[128], cmd[128], *p, *err;	int data; 	ARGBEGIN{	case 'R':				/* From listen */		remoteside();		break;	case 'N':		remotenote();		break;	case 'h':		hflag++;		p = ARGF();		if(p==0)			usage();		strcpy(system, p);		break;	case 'c':		cflag++;		cmd[0] = '!';		cmd[1] = '\0';		while(p = ARGF()) {			strcat(cmd, " ");			strcat(cmd, p);		}		break;	default:		usage();	}ARGEND; 	if(argv);	if(argc != 0)		usage(); 	if(hflag == 0) {		p = getenv("cpu");		if(p == 0)			fatal(0, "set $cpu");		strcpy(system, p);	} 	if(err = rexcall(&data, system, srvname))		fatal(1, "%s: %s", err, system); 	/* Tell the remote side the command to execute and where our working directory is */	if(cflag)		writestr(data, cmd, "command", 0);	if(getwd(dat, sizeof(dat)) == 0)		writestr(data, "NO", "dir", 0);	else		writestr(data, dat, "dir", 0); 	readstr(data, buf, sizeof(buf), "pid");	noteproc(buf); 	/* Wait for the other end to execute and start our file service	 * of /mnt/term */	readstr(data, buf, sizeof(buf), "FS");	if(strncmp("FS", buf, 2) != 0) {		print("remote cpu: %s", buf);		exits(buf);	} 	/* Begin serving the gnot namespace */	close(0);	dup(data, 0);	close(data);	execl(exportfs, exportfs, 0);	fatal(1, "starting exportfs");} voidfatal(int syserr, char *fmt, ...){	char buf[ERRLEN]; 	doprint(buf, buf+sizeof(buf), fmt, (&fmt+1));	if(syserr)		fprint(2, "cpu: %s: %r\n", buf);	else		fprint(2, "cpu: %s\n", buf);	exits(buf);} /* Invoked with stdin, stdout and stderr connected to the network connection */voidremoteside(void){	char *err, user[NAMELEN], home[128], buf[128], xdir[128], cmd[128];	int i, n, fd, badchdir, gotcmd; 	if(err = srvauth(user))		fatal(1, err);	if(err = newns(user, 0))		fatal(1, err); 	/* Set environment values for the user */	putenv("user", user);	sprint(home, "/usr/%s", user);	putenv("home", home); 	/* Now collect invoking cpus current directory or possibly a command */	gotcmd = 0;	readstr(0, xdir, sizeof(xdir), "dir/cmd");	if(xdir[0] == '!') {		strcpy(cmd, &xdir[1]);		gotcmd = 1;		readstr(0, xdir, sizeof(xdir), "dir");	} 	/* Establish the new process at the current working directory of the	 * gnot */	badchdir = 0;	if(strcmp(xdir, "NO") == 0)		chdir(home);	else if(chdir(xdir) < 0) {		badchdir = 1;		chdir(home);	} 	sprint(buf, "%d", getpid());	writestr(1, buf, "pid", 0); 	/* Start the gnot serving its namespace */	writestr(1, "FS", "FS", 0);	writestr(1, "/", "exportfs dir", 0); 	n = read(1, buf, sizeof(buf));	if(n != 2 || buf[0] != 'O' || buf[1] != 'K')		exits("remote tree"); 	fd = dup(1, -1);	if(mount(fd, "/mnt/term", MREPL, "", "") < 0)		exits("mount failed"); 	close(fd); 	for(i = 0; i < 3; i++)		close(i); 	if(open("/mnt/term/dev/cons", OREAD) != 0)		exits("open stdin");	if(open("/mnt/term/dev/cons", OWRITE) != 1)		exits("open stdout");	dup(1, 2); 	if(badchdir)		print("cpu: failed to chdir to '%s'\n", xdir); 	if(gotcmd)		execl("/bin/rc", "rc", "-lc", cmd, 0);	else		execl("/bin/rc", "rc", "-li", 0);	fatal(1, "exec shell");} voidnoteproc(char *pid){	char cmd[NAMELEN], syserr[ERRLEN], *err;	int notepid, n;	Waitmsg w; 	notepid = fork();	if(notepid < 0)		fatal(1, "forking noteproc");	if(notepid == 0)		return; 	notify(catcher); 	if(err = rexcall(&notechan, system, notesrv))		fprint(2, "cpu: can't dial for notify: %s: %r\n", err);	else{		sprint(cmd, "%s", pid);		writestr(notechan, cmd, "notepid", 0);	} 	for(;;) {		n = wait(&w);		if(n < 0) {			errstr(syserr);			if(strcmp(syserr, "interrupted") != 0){				fprint(2, "cpu: wait: %s\n", syserr);				exits("waiterr");			}		}		if(n == notepid)			break;	}	exits(w.msg);} voidcatcher(void *a, char *text){	if(a);	writestr(notechan, text, "catcher", 1);	noted(NCONT);} voidremotenote(void){	char buf[128], *err;	int pid; 	if(err = srvauth(buf))		exits(err);	readstr(0, buf, sizeof(buf), "read pid");	pid = -atoi(buf);	for(;;) {		readstr(0, buf, sizeof(buf), 0);		if(postnote(pid, buf) < 0)			exits("posting");	}} voidusage(void){	fprint(2, "usage: cpu [-h system] [-c cmd args ...]\n");	exits("usage");} char*rexcall(int *fd, char *host, char *service){	char *err;	char *na; 	na = netmkaddr(host, 0, service);	if((*fd = dial(na, 0, 0, 0)) < 0)		return "can't dial";	if(err = auth(*fd, na))		return err;	return 0;} voidwritestr(int fd, char *str, char *thing, int ignore){	int l, n; 	l = strlen(str);	n = write(fd, str, l+1);	if(!ignore && n < 0)		fatal(1, "writing network: %s", thing);} voidreadstr(int fd, char *str, int len, char *thing){	int n; 	while(len) {		n = read(fd, str, 1);		if(n < 0) {			if(thing == 0)				exits("readstr");			fatal(1, "reading network: %s", thing);		}		if(*str == '\0')			return;		str++;		len--;	}	fatal(0, "%s: too long", thing);}