new venti library.

src/libventi/version.c

@@ -0,0 +1,115 @@
+#include <u.h>
+#include <libc.h>
+#include <venti.h>
+
+static char *okvers[] = {
+	"02",
+	nil,
+};
+
+/*
+static char EBigString[] = "string too long";
+static char EBigPacket[] = "packet too long";
+static char ENullString[] = "missing string";
+*/
+static char EBadVersion[] = "bad format in version string";
+
+static int
+vtreadversion(VtConn *z, char *q, char *v, int nv)
+{
+	int n;
+
+	for(;;){
+		if(nv <= 1){
+			werrstr("version too long");
+			return -1;
+		}
+		n = read(z->infd, v, 1);
+		if(n <= 0){
+			if(n == 0)
+				werrstr("unexpected eof");
+			return -1;
+		}
+		if(*v == '\n'){
+			*v = 0;
+			break;
+		}
+		if((uchar)*v < ' ' || (uchar)*v > 0x7f || (*q && *v != *q)){
+			werrstr(EBadVersion);
+			return -1;
+		}
+		v++;
+		nv--;
+		if(*q)
+			q++;
+	}
+	return 0;
+}
+
+int
+vtversion(VtConn *z)
+{
+	char buf[VtMaxStringSize], *p, *ep, *prefix, *pp;
+	int i;
+
+	qlock(&z->lk);
+	if(z->state != VtStateAlloc){
+		werrstr("bad session state");
+		qunlock(&z->lk);
+		return -1;
+	}
+
+	qlock(&z->inlk);
+	qlock(&z->outlk);
+
+	p = buf;
+	ep = buf + sizeof buf;
+	prefix = "venti-";
+	p = seprint(p, ep, "%s", prefix);
+	p += strlen(p);
+	for(i=0; okvers[i]; i++)
+		p = seprint(p, ep, "%s%s", i ? ":" : "", okvers[i]);
+	p = seprint(p, ep, "-libventi\n");
+	assert(p-buf < sizeof buf);
+
+	if(write(z->outfd, buf, p-buf) != p-buf)
+		goto Err;
+	vtdebug(z, "version string out: %s", buf);
+
+	if(vtreadversion(z, prefix, buf, sizeof buf) < 0)
+		goto Err;
+	vtdebug(z, "version string in: %s", buf);
+
+	p = buf+strlen(prefix);
+	for(;;){
+		pp = strpbrk(p, ":-");
+		for(i=0; okvers[i]; i++)
+			if(strlen(okvers[i]) == pp-p && memcmp(okvers[i], p, pp-p) == 0){
+				*pp = 0;
+				z->version = vtstrdup(p);
+				goto Okay;
+			}
+	}
+	werrstr("unable to negotiate version");
+	goto Err;
+
+Okay:
+	z->state = VtStateConnected;
+	qunlock(&z->inlk);
+	qunlock(&z->outlk);
+	qunlock(&z->lk);
+	return 0;
+
+Err:
+	if(z->infd >= 0)
+		close(z->infd);
+	if(z->outfd >= 0 && z->outfd != z->infd)
+		close(z->outfd);
+	z->infd = -1;
+	z->outfd = -1;
+	z->state = VtStateClosed;
+	qunlock(&z->inlk);
+	qunlock(&z->outlk);
+	qunlock(&z->lk);
+	return -1;
+}