1 files changed, 115 insertions, 0 deletions
diff --git a/libaxl_send_handshake.c b/libaxl_send_handshake.c
new file mode 100644
index 0000000..80d48aa
--- /dev/null
+++ b/libaxl_send_handshake.c
@@ -0,0 +1,115 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+static int
+send_all(int fd, void *restrict data, size_t n, int flags, size_t *restrict progressp)
+{
+	char *bs = data;
+	ssize_t r;
+
+	while (n) {
+		r = liberror_send(fd, bs, n, flags, "<display server>");
+		if (r < 0)
+			return -1;
+		bs += r, n -= (size_t)r;
+		*progressp += (size_t)r;
+	}
+
+	return 0;
+}
+
+int
+libaxl_send_handshake(LIBAXL_CONTEXT *restrict ctx, const char *auth_name, size_t auth_name_len,
+                      const char *auth_data, size_t auth_data_len, int flags)
+{
+	LIBAXL_CONNECTION *conn = ctx->conn;
+	LIBAXL_CONTEXT *pending, **pendingp;
+	size_t len, o = 0;
+	char *buf;
+
+	RLOCK_CONNECTION_SEND(conn);
+	pending = conn->pending_out;
+	conn->info.protocol_version_major = LIBAXL_PROTOCOL_MAJOR;
+	conn->info.protocol_version_minor = LIBAXL_PROTOCOL_MINOR;
+	conn->info.protocol_version       = LIBAXL_PROTOCOL_VERSION;
+	conn->info.protocol_byte_order    = LIBAXL_MSB_FIRST; /* TODO Use LIBAXL_LSB_FIRST if preferable */
+	RUNLOCK_CONNECTION_SEND(conn);
+	if (pending) {
+		liberror_save_backtrace(NULL);
+		liberror_set_error(pending == ctx
+		                   ? "Request from the previous call is pending to be flush"
+		                   : "A request from another thread is pending to be flushed",
+		                   "libaxl_send_handshake", "errno", EALREADY);
+		errno = EALREADY;
+		return LIBAXL_ERROR_SYSTEM;
+	}
+
+	if (auth_name_len > UINT16_MAX) {
+		liberror_save_backtrace(NULL);
+		liberror_set_error("Authorisation protocol name is too long", "libaxl_send_handshake", "errno", EINVAL);
+		errno = EINVAL;
+		return LIBAXL_ERROR_SYSTEM;
+	}
+
+	if (auth_data_len > UINT16_MAX) {
+		liberror_save_backtrace(NULL);
+		liberror_set_error("Authorisation data is too long", "libaxl_send_handshake", "errno", EINVAL);
+		errno = EINVAL;
+		return LIBAXL_ERROR_SYSTEM;
+	}
+
+	buf = ctx->out_buf;
+	len = 12 + (auth_name_len + 3) / 4 * 4 + (auth_data_len + 3) / 4 * 4;
+	if (len > ctx->out_buf_size) {
+			buf = liberror_realloc(buf, len);
+			if (!buf)
+				return LIBAXL_ERROR_SYSTEM;
+			ctx->out_buf = buf;
+			ctx->out_buf_size = len;
+	}
+
+	buf[o++] = 'B'; /* TODO Use 'l' (LSB first) if preferable */
+	buf[o++] = 0;
+	*(uint16_t *)&buf[o] = htons(LIBAXL_PROTOCOL_MAJOR);
+	o += 2;
+	*(uint16_t *)&buf[o] = htons(LIBAXL_PROTOCOL_MINOR);
+	o += 2;
+	*(uint16_t *)&buf[o] = htons((uint16_t)auth_name_len);
+	o += 2;
+	*(uint16_t *)&buf[o] = htons((uint16_t)auth_data_len);
+	o += 2;
+	buf[o++] = 0;
+	buf[o++] = 0;
+	memcpy(&buf[o], auth_name, auth_name_len);
+	for (o += auth_name_len; o % 4; o++)
+		buf[o] = 0;
+	memcpy(&buf[o], auth_data, auth_data_len);
+	for (o += auth_data_len; o % 4; o++)
+		buf[o] = 0;
+
+	ctx->out_length = o;
+	ctx->out_progress = 0;
+
+	WLOCK_CONNECTION_SEND(conn);
+
+	if (send_all(conn->fd, ctx->out_buf, ctx->out_length, flags, &ctx->out_progress)) {
+		ctx->next_pending_out = NULL;
+		pendingp = &conn->pending_out;
+		while (*pendingp)
+			pendingp = &(*pendingp)->next_pending_out;
+		*pendingp = ctx;
+		ctx->refcount += 1;
+
+		WUNLOCK_CONNECTION_SEND(conn);
+
+		liberror_save_backtrace(NULL);
+		liberror_set_error("Handshake has been buffered and is ready to be sent",
+		                   "libaxl_send_request", "errno", EINPROGRESS);
+		errno = EINPROGRESS;
+		return LIBAXL_ERROR_SYSTEM;
+	}
+
+	WUNLOCK_CONNECTION_SEND(conn);
+
+	return 0;
+}