a

libc/dial.c

@@ -0,0 +1,209 @@
+#include <u.h>
+#include <libc.h>
+
+typedef struct DS DS;
+
+static int	call(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'
+ */
+int
+dial(char *dest, char *local, char *dir, int *cfdp)
+{
+	DS ds;
+	int rv;
+	char err[ERRMAX], alterr[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] = '\0';
+	errstr(err, sizeof err);
+	if(strstr(err, "refused") != 0){
+		werrstr("%s", err);
+		return rv;
+	}
+	ds.netdir = "/net.alt";
+	rv = csdial(&ds);
+	if(rv >= 0)
+		return rv;
+
+	alterr[0] = 0;
+	errstr(alterr, sizeof alterr);
+	if(strstr(alterr, "translate") || strstr(alterr, "does not exist"))
+		werrstr("%s", err);
+	else
+		werrstr("%s", alterr);
+	return rv;
+}
+
+static int
+csdial(DS *ds)
+{
+	int n, fd, rv;
+	char *p, buf[Maxstring], clone[Maxpath], err[ERRMAX], besterr[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);
+	}
+
+	/*
+	 *  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.
+	 */
+	*besterr = 0;
+	rv = -1;
+	seek(fd, 0, 0);
+	strcpy(err, "cs gave empty translation list");
+	while((n = read(fd, buf, sizeof(buf) - 1)) > 0){
+		buf[n] = 0;
+		p = strchr(buf, ' ');
+		if(p == 0)
+			continue;
+		*p++ = 0;
+		rv = call(buf, p, ds);
+		if(rv >= 0)
+			break;
+		err[0] = '\0';
+		errstr(err, sizeof err);
+		if(strstr(err, "does not exist") == 0)
+			strcpy(besterr, err);
+	}
+	close(fd);
+
+	if(rv < 0 && *besterr)
+		werrstr("%s", besterr);
+	else
+		werrstr("%s", err);
+	return rv;
+}
+
+static int
+call(char *clone, char *dest, DS *ds)
+{
+	int fd, cfd, n;
+	char name[Maxpath], data[Maxpath], *p;
+
+	cfd = open(clone, 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(clone, '/');
+	*p = 0;
+	if(ds->dir)
+		snprint(ds->dir, NETPATHLEN, "%s/%s", clone, name);
+	snprint(data, sizeof(data), "%s/%s/data", clone, name);
+
+	/* connect */
+	if(ds->local)
+		snprint(name, sizeof(name), "connect %s %s", dest, ds->local);
+	else
+		snprint(name, sizeof(name), "connect %s", dest);
+	if(write(cfd, name, strlen(name)) < 0){
+		close(cfd);
+		return -1;
+	}
+
+	/* open data connection */
+	fd = open(data, ORDWR);
+	if(fd < 0){
+print("open %s: %r\n", data);
+		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 {
+		if(*ds->buf != '/' && *ds->buf != '#'){
+			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;
+	}
+}