Clean up error handling a bit.

Adds some error "codes" and tries to standardize on them.

client_test.c

@@ -104,11 +104,11 @@ main(int argc, char **argv)
 	printf("received payload of " SSIZE_T_PARAM " bytes:\n---\n%s\n---\n",
 		len, out);
 
-	assert(0 == dumb_close(&ws));
+	assert(DWS_OK == dumb_close(&ws));
 	printf("sent a CLOSE frame!\n");
 
 	// Our socket should be closed now
-	assert(-1 == dumb_recv(&ws, buf, sizeof(buf)));
+	assert(DWS_ERR_READ == dumb_recv(&ws, buf, sizeof(buf)));
 	printf("socket looks closed!\n");
 
 	return 0;

dws.c

@@ -133,7 +133,7 @@ choose(unsigned int upper_bound)
  *
  * Since RFC6455 says we don't care about the random 16-byte value used
  * for the key (the server never decodes it), why bother actually writing
- * propery base64 encoding when we can just pick 22 valid base64 characters
+ * a proper base64 encoding when we can just pick 22 valid base64 characters
  * to make our key?
  */
 static void
@@ -202,8 +202,8 @@ ws_read(struct websocket *ws, void *buf, size_t buflen)
 				break;
 			}
 			else if (sz == -1) {
-				// TODO: check some common errno's and return something better.
-				printf("%s: err %s\n", __func__, strerror(errno));
+				// TODO: check some common errno's and return
+				// something better.
 				return -1;
 			}
 		}
@@ -315,8 +315,6 @@ ws_read_txt(struct websocket *ws, void *buf, size_t buflen)
  *
  * Will write the entirety of the given buffer. Does not currently use any
  * poll like functionality, so will busy poll the socket!
- *
- * XXX: for now failures to write are fatal :X
  */
 static ssize_t
 ws_write(struct websocket *ws, const void *buf, size_t buflen)
@@ -325,7 +323,7 @@ ws_write(struct websocket *ws, const void *buf, size_t buflen)
 	char *_buf;
 
 	if (buflen > INT_MAX)
-		crap(1, "%s: buflen too large", __func__);
+		return -1;
 	if (buflen == 0)
 		return 0;
 
@@ -460,7 +458,7 @@ dumb_frame(uint8_t *frame, const uint8_t *data, size_t len)
 
 	// Just a quick safety check: we don't do large payloads
 	if (len > (1 << 24))
-		return -1;
+		return DWS_ERR_TOO_LARGE;
 
 	// Pretend we're in Eyes Wide Shut
 	dumb_mask(mask);
@@ -490,8 +488,8 @@ dumb_frame(uint8_t *frame, const uint8_t *data, size_t len)
  *
  * Returns:
  *  0 on success,
- * -1 if it failed to generate the handshake buffer,
- * -2 if it received an invalid handshake response,
+ *  DWS_ERR_HANDSHAKE_BUF if it failed to generate the handshake buffer,
+ *  DWS_ERR_HANDSHAKE_ERR if it received an invalid handshake response,
  *  fatal error otherwise.
  */
 int
@@ -507,7 +505,7 @@ dumb_handshake(struct websocket *ws, const char *path, const char *proto)
 	len = snprintf(buf, sizeof(buf), HANDSHAKE_TEMPLATE,
 				   path, ws->host, ws->port, key, proto);
 	if (len < 1)
-		return -1;
+		return DWS_ERR_HANDSHAKE_BUF;
 
 	// Send our upgrade request.
 	sz = ws_write(ws, buf, len);
@@ -517,14 +515,13 @@ dumb_handshake(struct websocket *ws, const char *path, const char *proto)
 	memset(buf, 0, sizeof(buf));
 	len = ws_read_txt(ws, buf, sizeof(buf));
 	if (len == -1)
-		return -1;
+		return DWS_ERR_HANDSHAKE_BUF;
 
 	/* XXX: If we gave a crap, we'd validate the returned key per the
 	 * requirements of RFC6455 sec. 4.1, but we don't.
 	 */
 	if (memcmp(server_handshake, buf, sizeof(server_handshake) - 1)) {
-        printf("%s: bad handshake:\n%s\n", __func__, buf);
-        ret = -2;
+        ret = DWS_ERR_HANDSHAKE_RES;
     }
 
 	return ret;
@@ -543,9 +540,9 @@ dumb_handshake(struct websocket *ws, const char *path, const char *proto)
  *
  * Returns:
  *  0 on success,
- * -1 if it failed to create a socket,
- * -2 if it failed to resolve host (check h_errno),
- * -3 if it failed to connect(2).
+ *  DWS_ERR_CONN_CREATE if it failed to create a socket,
+ *  DWS_ERR_CONN_RESOLVE if it failed to resolve host (check h_errno),
+ *  DWS_ERR_CONN_CONNECT if it failed to connect(2).
  */
 int
 dumb_connect(struct websocket *ws, const char *host, uint16_t port)
@@ -564,7 +561,7 @@ dumb_connect(struct websocket *ws, const char *host, uint16_t port)
 
 	s = socket(AF_INET, SOCK_STREAM, 0);
 	if (s < 0)
-		return -1;
+		return DWS_ERR_CONN_CREATE;
 
 	memset(&hints, 0, sizeof(hints));
 	hints.ai_family = AF_INET;
@@ -575,15 +572,15 @@ dumb_connect(struct websocket *ws, const char *host, uint16_t port)
 	memset(port_buf, 0, sizeof(port_buf));
 	snprintf(port_buf, sizeof(port_buf), "%d", port);
 	if (getaddrinfo(host, port_buf, &hints, &res))
-		return -2;
+		return DWS_ERR_CONN_RESOLVE;
 
 	// XXX: for now we're lazy and only try the first addrinfo
 	if (connect(s, res->ai_addr, res->ai_addrlen))
-		return -3;
+		return DWS_ERR_CONN_CONNECT;
 
 	// Set to non blocking
 	if (fcntl(s, F_SETFL, O_NONBLOCK) == -1)
-		return -3;
+		return DWS_ERR_CONN_CONNECT;
 
 	// Store some state
 	ws->port = port;
@@ -651,8 +648,8 @@ dumb_connect_tls(struct websocket *ws, const char *host, uint16_t port,
  *
  * Returns:
  *  the amount of bytes sent,
- * -1 on failure to calloc(3) a buffer for the dumb websocket frame,
- *  or whatever ws_write might return on error (zero or a negative value)
+ *  DWS_ERR_MALLOC on failure to calloc(3) a buffer for the dumb websocket
+ *  frame, or whatever ws_write might return on error (zero or a negative value)
  */
 ssize_t
 dumb_send(struct websocket *ws, const void *payload, size_t len)
@@ -663,7 +660,7 @@ dumb_send(struct websocket *ws, const void *payload, size_t len)
 	// We need payload size + 14 bytes minimum, but pad a little extra
 	frame = calloc(1, len + 16);
 	if (frame == NULL)
-		return -1;
+		return DWS_ERR_MALLOC;
 
 	frame_len = dumb_frame(frame, payload, len);
 	if (frame_len < 0)
@@ -691,7 +688,7 @@ dumb_send(struct websocket *ws, const void *payload, size_t len)
  *
  * Returns:
  *  the number of bytes received in the payload (not including frame headers),
- * -1 on failure to read(2) data, DWS_WANT_POLL or DWS_SHUTDOWN.
+ *  DWS_ERR_READ on failure to read(2) data, DWS_WANT_POLL or DWS_SHUTDOWN.
  */
 ssize_t
 dumb_recv(struct websocket *ws, void *buf, size_t buflen)
@@ -702,12 +699,15 @@ dumb_recv(struct websocket *ws, void *buf, size_t buflen)
 
 	// Read first 2 bytes to figure out the framing details.
 	n = ws_read(ws, frame, 2);
-	if (n < 0)
+	if (n < 0) {
+		if (n == -1)
+			return DWS_ERR_READ;
 		return n;
+	}
 
 	// Now to validate the frame...
 	if (!(frame[0] & 0x80)) {
-		// XXX: We don't currently fragmentation
+		// XXX: We don't currently support fragmentation
 		crap(1, "%s: fragmentation unsupported", __func__);
 	}
 
@@ -737,20 +737,20 @@ dumb_recv(struct websocket *ws, void *buf, size_t buflen)
 		// arrives in network byte order.
 		n = ws_read_all(ws, frame + 2, 2);
 		if (n < 2)
-			return -1;
+			return DWS_ERR_READ;
 		payload_len = frame[2] << 8;
 		payload_len += frame[3];
 	} else if (payload_len > 126)
 		crap(1, "%s: unsupported payload size", __func__);
 
 	// We can now read the the payload, if there is one.
-	payload_len = MIN(payload_len, buflen);
+	payload_len = MIN((size_t)payload_len, buflen);
 	if (payload_len == 0)
 		return 0;
 
-	n = ws_read_all(ws, buf, (size_t) payload_len);
+	n = ws_read_all(ws, buf, (size_t)payload_len);
 	if (n < payload_len)
-		return -1;
+		return DWS_ERR_READ;
 
 	return payload_len;
 }
@@ -766,9 +766,9 @@ dumb_recv(struct websocket *ws, void *buf, size_t buflen)
  *
  * Returns:
  *  0 on success,
- * -1 on failure during write(2),
- * -2 on failure to receive(2) the response,
- * -3 on the response being invalid (i.e. not a PONG)
+ *  DWS_ERR_WRITE on failure during write(2),
+ *  DWS_ERR_READ on failure to receive(2) the response,
+ *  DWS_ERR_INVALID on the response being invalid (i.e. not a PONG)
  */
 int
 dumb_ping(struct websocket *ws)
@@ -784,28 +784,29 @@ dumb_ping(struct websocket *ws)
 
 	len = ws_write(ws, frame, (size_t) len);
 	if (len < 1)
-		return -1;
+		return DWS_ERR_WRITE;
 
 	memset(frame, 0, sizeof(frame));
 
 	// Read first 2 bytes.
 	len = ws_read_all(ws, frame, 2);
 	if (len < 0)
-		return -2;
+		return DWS_ERR_READ;
 
 	// We should have a PONG reply.
 	if (frame[0] != (0x80 + PONG))
-		return -3;
+		return DWS_ERR_INVALID;
 
 	payload_len = frame[1] & 0x7F;
 	if (payload_len >= 126)
 		crap(1, "dumb_ping: unsupported pong payload size > 125");
 
 	// Dump the rest of the data on the floor.
 	if (payload_len > 0) {
-		len = ws_read_all(ws, frame + 2, MIN(payload_len, sizeof(frame) - 2));
+		len = ws_read_all(ws, frame + 2,
+		    MIN((size_t)payload_len, sizeof(frame) - 2));
 		if (len < 1)
-			return -3;
+			return DWS_ERR_INVALID;
 	}
 
 	return 0;
@@ -851,9 +852,9 @@ ws_shutdown(struct websocket *ws)
  *
  * Returns:
  *  0 on success,
- * -1 on failure to send(2) the close frame,
- * -2 on failure to read(2) a response,
- * -3 on a response being invalid (i.e. not a CLOSE),
+ *  DWS_ERR_WRITE on failure to send(2) the close frame,
+ *  DWS_ERR_READ on failure to read(2) a response,
+ *  DWS_ERR_INVALID on a response being invalid (i.e. not a CLOSE),
  */
 int
 dumb_close(struct websocket *ws)
@@ -869,30 +870,31 @@ dumb_close(struct websocket *ws)
 
 	len = ws_write(ws, frame, (size_t) len);
 	if (len < 1)
-		return -1;
+		return DWS_ERR_WRITE;
 
 	memset(frame, 0, sizeof(frame));
 
 	// A valid RFC6455 websocket server MUST send a Close frame in response
 	// Read first 2 bytes.
-    len = ws_read_all(ws, frame, 2);
+	len = ws_read_all(ws, frame, 2);
 	if (len != 2)
-		return -2;
+		return DWS_ERR_READ;
 
 	// If we don't have a CLOSE frame...someone screwed up before calling
 	// dumb_close and there's still unread data!
 	if (frame[0] != (0x80 + CLOSE))
-		return -3;
+		return DWS_ERR_INVALID;
 
 	payload_len = frame[1] & 0x7F;
 	if (payload_len > 126)
 		crap(1, "dumb_close: unsupported close payload size > 125");
 
 	// Dump the rest of the data on the floor.
 	if (payload_len > 0) {
-		len = ws_read_all(ws, frame + 2, MIN(payload_len, sizeof(frame) - 2));
+		len = ws_read_all(ws, frame + 2,
+		    MIN((size_t)payload_len, sizeof(frame) - 2));
 		if (len < 1)
-			return -4;
+			return DWS_ERR_READ;
 	}
 
 	ws_shutdown(ws);

dws.h

@@ -58,10 +58,29 @@ struct websocket {
 	// TODO: add basic auth details?
 };
 
+/*
+ * Possible non-error responses from dumb_recv() based on the state of the
+ * socket or the next websocket control message (e.g. PING).
+ */
 #define DWS_WANT_POLL	-2
 #define DWS_WANT_PONG	-3
 #define DWS_SHUTDOWN	-4
 
+/*
+ * Simplistic error code approach using define's.
+ */
+#define DWS_OK			0
+#define DWS_ERR_CONN_CREATE	-1
+#define DWS_ERR_CONN_RESOLVE	-2
+#define DWS_ERR_CONN_CONNECT	-3
+#define DWS_ERR_MALLOC		-4
+#define DWS_ERR_READ		-5
+#define DWS_ERR_WRITE		-6
+#define DWS_ERR_INVALID		-7
+#define DWS_ERR_HANDSHAKE_BUF	-8
+#define DWS_ERR_HANDSHAKE_RES	-9
+#define DWS_ERR_TOO_LARGE	-10
+
 int dumb_connect(struct websocket *ws, const char*, uint16_t);
 int dumb_connect_tls(struct websocket *ws, const char*, uint16_t, int);
 int dumb_handshake(struct websocket *s, const char*, const char*);