remote_bitbang: Convert to use getaddrinfo()

Since gethostbyname() is deprecated and inconvenient, rewrite to use
getaddrinfo() using an implementation more or less copied from its man
page. This automatically enables support for IPv6.

This also fixes a FTBFS on ARM due to alignment issues.

Change-Id: I990a49506cac4b26faf77587937e506138371f7c
Signed-off-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>
Reviewed-on: http://openocd.zylin.com/1379


Reviewed-by: Paul Fertser <fercerpav@gmail.com>
Tested-by: jenkins
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>

src/jtag/drivers/remote_bitbang.c

@@ -43,8 +43,8 @@
 		exit(-1); \
 	} while (0)
 
-static char remote_bitbang_host[REMOTE_BITBANG_HOST_MAX] = "openocd";
-static uint16_t remote_bitbang_port;
+static char *remote_bitbang_host;
+static char *remote_bitbang_port;
 
 FILE *remote_bitbang_in;
 FILE *remote_bitbang_out;
@@ -74,6 +74,9 @@ static int remote_bitbang_quit(void)
 		return ERROR_FAIL;
 	}
 
+	free(remote_bitbang_host);
+	free(remote_bitbang_port);
+
 	LOG_INFO("remote_bitbang interface quit");
 	return ERROR_OK;
 }
@@ -132,40 +135,41 @@ static struct bitbang_interface remote_bitbang_bitbang = {
 
 static int remote_bitbang_init_tcp(void)
 {
-	LOG_INFO("Connecting to %s:%i", remote_bitbang_host, remote_bitbang_port);
-	int fd = socket(PF_INET, SOCK_STREAM, 0);
-	if (fd < 0) {
-		LOG_ERROR("socket: %s", strerror(errno));
+	struct addrinfo hints = { .ai_family = AF_UNSPEC, .ai_socktype = SOCK_STREAM };
+	struct addrinfo *result, *rp;
+	int fd;
+
+	LOG_INFO("Connecting to %s:%s",
+			remote_bitbang_host ? remote_bitbang_host : "localhost",
+			remote_bitbang_port);
+
+	/* Obtain address(es) matching host/port */
+	int s = getaddrinfo(remote_bitbang_host, remote_bitbang_port, &hints, &result);
+	if (s != 0) {
+		LOG_ERROR("getaddrinfo: %s\n", gai_strerror(s));
 		return ERROR_FAIL;
 	}
 
-	struct hostent *hent = gethostbyname(remote_bitbang_host);
-	if (hent == NULL) {
-		char *errorstr = "???";
-		switch (h_errno) {
-			case HOST_NOT_FOUND:
-				errorstr = "host not found";
-				break;
-			case NO_ADDRESS:
-				errorstr = "no address";
-				break;
-			case NO_RECOVERY:
-				errorstr = "no recovery";
-				break;
-			case TRY_AGAIN:
-				errorstr = "try again";
-				break;
-		}
-		LOG_ERROR("gethostbyname: %s", errorstr);
-		return ERROR_FAIL;
+	/* getaddrinfo() returns a list of address structures.
+	 Try each address until we successfully connect(2).
+	 If socket(2) (or connect(2)) fails, we (close the socket
+	 and) try the next address. */
+
+	for (rp = result; rp != NULL ; rp = rp->ai_next) {
+		fd = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
+		if (fd == -1)
+			continue;
+
+		if (connect(fd, rp->ai_addr, rp->ai_addrlen) != -1)
+			break; /* Success */
+
+		close(fd);
 	}
 
-	struct sockaddr_in addr;
-	addr.sin_family = AF_INET;
-	addr.sin_port = htons(remote_bitbang_port);
-	addr.sin_addr = *(struct in_addr *)hent->h_addr;
-	if (connect(fd, (struct sockaddr *)&addr, sizeof(struct sockaddr_in)) < 0) {
-		LOG_ERROR("connect: %s", strerror(errno));
+	freeaddrinfo(result); /* No longer needed */
+
+	if (rp == NULL) { /* No address succeeded */
+		LOG_ERROR("Failed to connect: %s", strerror(errno));
 		return ERROR_FAIL;
 	}
 
@@ -187,6 +191,11 @@ static int remote_bitbang_init_tcp(void)
 
 static int remote_bitbang_init_unix(void)
 {
+	if (remote_bitbang_host == NULL) {
+		LOG_ERROR("host/socket not specified");
+		return ERROR_FAIL;
+	}
+
 	LOG_INFO("Connecting to unix socket %s", remote_bitbang_host);
 	int fd = socket(PF_UNIX, SOCK_STREAM, 0);
 	if (fd < 0) {
@@ -225,7 +234,7 @@ static int remote_bitbang_init(void)
 	bitbang_interface = &remote_bitbang_bitbang;
 
 	LOG_INFO("Initializing remote_bitbang driver");
-	if (remote_bitbang_port == 0)
+	if (remote_bitbang_port == NULL)
 		return remote_bitbang_init_unix();
 	return remote_bitbang_init_tcp();
 }
@@ -233,7 +242,10 @@ static int remote_bitbang_init(void)
 COMMAND_HANDLER(remote_bitbang_handle_remote_bitbang_port_command)
 {
 	if (CMD_ARGC == 1) {
-		COMMAND_PARSE_NUMBER(u16, CMD_ARGV[0], remote_bitbang_port);
+		uint16_t port;
+		COMMAND_PARSE_NUMBER(u16, CMD_ARGV[0], port);
+		free(remote_bitbang_port);
+		remote_bitbang_port = port == 0 ? NULL : strdup(CMD_ARGV[0]);
 		return ERROR_OK;
 	}
 	return ERROR_COMMAND_SYNTAX_ERROR;
@@ -242,8 +254,8 @@ COMMAND_HANDLER(remote_bitbang_handle_remote_bitbang_port_command)
 COMMAND_HANDLER(remote_bitbang_handle_remote_bitbang_host_command)
 {
 	if (CMD_ARGC == 1) {
-		strncpy(remote_bitbang_host, CMD_ARGV[0], REMOTE_BITBANG_HOST_MAX);
-		remote_bitbang_host[REMOTE_BITBANG_HOST_MAX-1] = '\0';
+		free(remote_bitbang_host);
+		remote_bitbang_host = strdup(CMD_ARGV[0]);
 		return ERROR_OK;
 	}
 	return ERROR_COMMAND_SYNTAX_ERROR;
@@ -255,7 +267,7 @@ static const struct command_registration remote_bitbang_command_handlers[] = {
 		.handler = remote_bitbang_handle_remote_bitbang_port_command,
 		.mode = COMMAND_CONFIG,
 		.help = "Set the port to use to connect to the remote jtag.\n"
-			"  if 0, use unix sockets to connect to the remote jtag.",
+			"  if 0 or unset, use unix sockets to connect to the remote jtag.",
 		.usage = "port_number",
 	},
 	{
@@ -263,7 +275,7 @@ static const struct command_registration remote_bitbang_command_handlers[] = {
 		.handler = remote_bitbang_handle_remote_bitbang_host_command,
 		.mode = COMMAND_CONFIG,
 		.help = "Set the host to use to connect to the remote jtag.\n"
-			"  if port is 0, this is the name of the unix socket to use.",
+			"  if port is 0 or unset, this is the name of the unix socket to use.",
 		.usage = "host_name",
 	},
 	COMMAND_REGISTRATION_DONE,