#include <u.h>#include <libc.h> typedef struct DS DS; static int	call(char*, char*, char*, DS*);static int	csdial(DS*);static void	_dial_string_parse(char*, DS*); enum{	Maxstring	= 128,	Maxpath		= 256,}; struct DS {	/* dist string */	char	buf[Maxstring];	char	*netdir;	char	*proto;	char	*rem; 	/* other args */	char	*local;	char	*dir;	int	*cfdp;};  /* *  the dialstring is of the form '[/net/]proto!dest' */intdial(char *dest, char *local, char *dir, int *cfdp){	DS ds;	int rv;	char err[ERRMAX]; 	ds.local = local;	ds.dir = dir;	ds.cfdp = cfdp; 	_dial_string_parse(dest, &ds);	if(ds.netdir)		return csdial(&ds); 	ds.netdir = "/net";	rv = csdial(&ds);	if(rv >= 0)		return rv;	*err = 0;	errstr(err, sizeof err);	if(strcmp(err, "interrupted") == 0 || strstr(err, "refused") != nil){		errstr(err, sizeof err);		return rv;	} 	ds.netdir = "/net.alt";	rv = csdial(&ds);	if(rv >= 0)		return rv;	errstr(err, sizeof err);	if(strstr(err, "translate") == nil && strstr(err, "does not exist") == nil)		errstr(err, sizeof err);	return rv;} static intcsdial(DS *ds){	int n, fd, rv;	char *rem, *loc, buf[Maxstring], clone[Maxpath], err[ERRMAX]; 	/*	 *  open connection server	 */	snprint(buf, sizeof(buf), "%s/cs", ds->netdir);	fd = open(buf, ORDWR);	if(fd < 0){		/* no connection server, don't translate */		snprint(clone, sizeof(clone), "%s/%s/clone", ds->netdir, ds->proto);		return call(clone, ds->rem, ds->local, ds);	} 	/*	 *  ask connection server to translate	 */	snprint(buf, sizeof(buf), "%s!%s", ds->proto, ds->rem);	if(write(fd, buf, strlen(buf)) < 0){		close(fd);		return -1;	} 	/*	 *  loop through each address from the connection server till	 *  we get one that works.	 */	rv = -1;	*err = 0;	seek(fd, 0, 0);	while((n = read(fd, buf, sizeof(buf) - 1)) > 0){		buf[n] = 0;		rem = strchr(buf, ' ');		if(rem == nil)			continue;		*rem++ = 0;		loc = strchr(rem, ' ');		if(loc != nil)			*loc++ = 0;		rv = call(buf, rem, ds->local!=nil? ds->local: loc, ds);		if(rv >= 0)			break;		errstr(err, sizeof err);		if(strcmp(err, "interrupted") == 0)			break;		if(strstr(err, "does not exist") != nil)			errstr(err, sizeof err);	/* get previous error back */	}	close(fd); 	/* restore errstr if any */	if(rv < 0 && *err)		errstr(err, sizeof err); 	return rv;} static intcall(char *clone, char *remote, char *local, DS *ds){	int fd, cfd, n;	char cname[Maxpath], name[Maxpath], data[Maxpath], *p; 	/* because cs is in a different name space, replace the mount point */	if(*clone == '/' || *clone == '#'){		p = strchr(clone+1, '/');		if(p == nil)			p = clone;		else			p++;	} else		p = clone;	snprint(cname, sizeof cname, "%s/%s", ds->netdir, p); 	cfd = open(cname, ORDWR);	if(cfd < 0)		return -1; 	/* get directory name */	n = read(cfd, name, sizeof(name)-1);	if(n < 0){		close(cfd);		return -1;	}	name[n] = 0;	for(p = name; *p == ' '; p++)		;	snprint(name, sizeof(name), "%ld", strtoul(p, 0, 0));	p = strrchr(cname, '/');	*p = 0;	if(ds->dir)		snprint(ds->dir, NETPATHLEN, "%s/%s", cname, name);	snprint(data, sizeof(data), "%s/%s/data", cname, name); 	/* connect */	if(local != nil)		snprint(name, sizeof(name), "connect %s %s", remote, local);	else		snprint(name, sizeof(name), "connect %s", remote);	if(write(cfd, name, strlen(name)) < 0){		close(cfd);		return -1;	} 	/* open data connection */	fd = open(data, ORDWR);	if(fd < 0){		close(cfd);		return -1;	}	if(ds->cfdp)		*ds->cfdp = cfd;	else		close(cfd);	return fd;} /* *  parse a dial string */static void_dial_string_parse(char *str, DS *ds){	char *p, *p2; 	strncpy(ds->buf, str, Maxstring);	ds->buf[Maxstring-1] = 0; 	p = strchr(ds->buf, '!');	if(p == 0) {		ds->netdir = 0;		ds->proto = "net";		ds->rem = ds->buf;	} else {		p2 = ds->buf;		if(*p2 == '#'){			p2 = strchr(p2, '/');			if(p2 == nil || p2 > p)				p2 = ds->buf;		}		if(*p2 != '/'){			ds->netdir = 0;			ds->proto = ds->buf;		} else {			for(p2 = p; *p2 != '/'; p2--)				;			*p2++ = 0;			ds->netdir = ds->buf;			ds->proto = p2;		}		*p = 0;		ds->rem = p + 1;	}}