Change license and style, reorganise file, make makefile portable, and fix bugs1.3

Signed-off-by: Mattias Andrée <maandree@kth.se>

1 files changed, 159 insertions, 0 deletions

diff --git a/communication.c b/communication.c
new file mode 100644
index 0000000..13d5046
--- /dev/null
+++ b/communication.c
@@ -0,0 +1,159 @@
+/* See LICENSE file for copyright and license details. */
+#include "communication.h"
+#include "state.h"
+#include "servers-coopgamma.h"
+
+#include <sys/socket.h>
+#include <errno.h>
+#include <string.h>
+
+
+/**
+ * Send a message
+ * 
+ * @param   conn  The index of the connection
+ * @param   buf   The data to send
+ * @param   n     The size of `buf`
+ * @return        Zero on success, -1 on error, 1 if disconncted
+ *                EINTR, EAGAIN, EWOULDBLOCK, and ECONNRESET count
+ *                as success (ECONNRESET cause 1 to be returned),
+ *                and are handled appropriately.
+ */
+int
+send_message(size_t conn, char *restrict buf, size_t n)
+{
+	struct ring *restrict ring = outbound + conn;
+	int fd = connections[conn];
+	int saved_errno;
+	size_t ptr = 0;
+	ssize_t sent;
+	size_t chunksize = n;
+	size_t sendsize;
+	size_t old_n;
+	char *old_buf;
+	size_t old_ptr;
+
+	while ((old_buf = ring_peek(ring, &old_n))) {
+		for (old_ptr = 0; old_ptr < n;) {
+			sendsize = old_n - old_ptr < chunksize ? old_n - old_ptr : chunksize;
+			sent = send(fd, old_buf + old_ptr, sendsize, MSG_NOSIGNAL);
+			if (sent < 0) {
+				if (errno == EPIPE)
+					errno = ECONNRESET;
+				if (errno != EMSGSIZE)
+					goto fail;
+				chunksize >>= 1;
+				if (!chunksize)
+					goto fail;
+				continue;
+			}
+			old_ptr += (size_t)sent;
+			ring_pop(ring, (size_t)sent);
+		}
+	}
+
+	while (ptr < n) {
+		sendsize = n - ptr < chunksize ? n - ptr : chunksize;
+		sent = send(fd, buf + ptr, sendsize, MSG_NOSIGNAL);
+		if (sent < 0) {
+			if (errno == EPIPE)
+				errno = ECONNRESET;
+			if (errno != EMSGSIZE)
+				goto fail;
+			chunksize >>= 1;
+			if (!chunksize)
+				goto fail;
+			continue;
+		}
+		ptr += (size_t)sent;
+	}
+
+	free(buf);
+	return 0;
+
+fail:
+	switch (errno) {
+	case EINTR:
+#if defined(EAGAIN)
+	case EAGAIN:
+#endif
+#if defined(EWOULDBLOCK) && (!defined(EAGAIN) || EAGAIN != EWOULDBLOCK)
+	case EWOULDBLOCK:
+#endif
+		if (ring_push(ring, buf + ptr, n - ptr) < 0)
+			goto proper_fail;
+		free(buf);
+		return 0;
+
+	case ECONNRESET:
+		free(buf);
+		if (connection_closed(fd) < 0)
+			return -1;
+		return 1;
+
+	default:
+		break;
+	}
+
+proper_fail:
+	saved_errno = errno;
+	free(buf);
+	errno = saved_errno;
+	return -1;
+}
+
+
+/**
+ * Send a custom error without an error number
+ * 
+ * @param   conn        The index of the connection
+ * @param   message_id  The ID of the message to which this message is a response
+ * @param   desc        The error description to send
+ * @return              1: Client disconnected
+ *                      0: Success (possibily delayed)
+ *                      -1: An error occurred
+ */
+int
+(send_error)(size_t conn, const char *restrict message_id, const char *restrict desc)
+{
+	char *restrict buf;
+	size_t n;
+
+	MAKE_MESSAGE(&buf, &n, 0,
+	             "Command: error\n"
+	             "In response to: %s\n"
+	             "Error: custom\n"
+	             "Length: %zu\n"
+	             "\n"
+	             "%s\n",
+	             message_id, strlen(desc) + 1, desc);
+
+	return send_message(conn, buf, n);
+}
+
+
+/**
+ * Send a standard error
+ * 
+ * @param   conn        The index of the connection
+ * @param   message_id  The ID of the message to which this message is a response
+ * @param   number      The value of `errno`, 0 to indicate success
+ * @return              1: Client disconnected
+ *                      0: Success (possibily delayed)
+ *                      -1: An error occurred
+ */
+int
+(send_errno)(size_t conn, const char *restrict message_id, int number)
+{
+	char *restrict buf;
+	size_t n;
+
+	MAKE_MESSAGE(&buf, &n, 0,
+	             "Command: error\n"
+	             "In response to: %s\n"
+	             "Error: %i\n"
+	             "\n",
+	             message_id, number);
+
+	return send_message(conn, buf, n);
+}