beginning of mds-colour

Signed-off-by: Mattias Andrée <maandree@operamail.com>

1 files changed, 323 insertions, 0 deletions

diff --git a/src/mds-colour.c b/src/mds-colour.c
new file mode 100644
index 0000000..267c0ba
--- /dev/null
+++ b/src/mds-colour.c
@@ -0,0 +1,323 @@
+/**
+ * mds — A micro-display server
+ * Copyright © 2014, 2015  Mattias Andrée (maandree@member.fsf.org)
+ * 
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include "mds-colour.h"
+/* TODO reload settings on SIGUSR2 */
+/* TODO --save-changes */
+
+#include <libmdsserver/macros.h>
+#include <libmdsserver/util.h>
+#include <libmdsserver/mds-message.h>
+
+#include <errno.h>
+#include <inttypes.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#define reconnect_to_display() -1
+
+
+
+#define MDS_COLOUR_VARS_VERSION  0
+
+
+
+/**
+ * This variable should declared by the actual server implementation.
+ * It must be configured before `main` is invoked.
+ * 
+ * This tells the server-base how to behave
+ */
+server_characteristics_t server_characteristics =
+  {
+    .require_privileges = 0,
+    .require_display = 1,
+    .require_respawn_info = 0,
+    .sanity_check_argc = 1,
+    .fork_for_safety = 0,
+    .danger_is_deadly = 0
+  };
+
+
+
+/**
+ * Value of the ‘Message ID’ header for the next message
+ */
+static uint32_t message_id = 1;
+
+/**
+ * Buffer for received messages
+ */
+static mds_message_t received;
+
+/**
+ * Whether the server is connected to the display
+ */
+static int connected = 1;
+
+/**
+ * Buffer for sending messages
+ */
+static char* send_buffer = NULL;
+
+/**
+ * The size allocated to `send_buffer` divided by `sizeof(char)`
+ */
+static size_t send_buffer_size = 0;
+
+
+
+/**
+ * This function will be invoked before `initialise_server` (if not re-exec:ing)
+ * or before `unmarshal_server` (if re-exec:ing)
+ * 
+ * @return  Non-zero on error
+ */
+int __attribute__((const)) preinitialise_server(void)
+{
+  return 0;
+}
+
+
+/**
+ * This function should initialise the server,
+ * and it not invoked after a re-exec.
+ * 
+ * @return  Non-zero on error
+ */
+int initialise_server(void)
+{
+  int stage = 0;
+  const char* const message =
+    "Command: intercept\n"
+    "Message ID: 0\n"
+    "Length: 62\n"
+    "\n"
+    "Command: list-colours\n"
+    "Command: get-colour\n"
+    "Command: set-colour\n";
+  
+  fail_if (full_send(message, strlen(message)));
+  fail_if (server_initialised() < 0);  stage++;
+  fail_if (mds_message_initialise(&received));
+  
+  return 0;
+ fail:
+  xperror(*argv);
+  if (stage == 1)
+    mds_message_destroy(&received);
+  return 1;
+}
+
+
+/**
+ * This function will be invoked after `initialise_server` (if not re-exec:ing)
+ * or after `unmarshal_server` (if re-exec:ing)
+ * 
+ * @return  Non-zero on error
+ */
+int postinitialise_server(void)
+{
+  if (connected)
+    return 0;
+  
+  fail_if (reconnect_to_display());
+  connected = 1;
+  return 0;
+ fail:
+  mds_message_destroy(&received);
+  return 1;
+}
+
+
+/**
+ * Calculate the number of bytes that will be stored by `marshal_server`
+ * 
+ * On failure the program should `abort()` or exit by other means.
+ * However it should not be possible for this function to fail.
+ * 
+ * @return  The number of bytes that will be stored by `marshal_server`
+ */
+size_t marshal_server_size(void)
+{
+  return 2 * sizeof(int) + sizeof(uint32_t) + mds_message_marshal_size(&received);
+}
+
+
+/**
+ * Marshal server implementation specific data into a buffer
+ * 
+ * @param   state_buf  The buffer for the marshalled data
+ * @return             Non-zero on error
+ */
+int marshal_server(char* state_buf)
+{
+  buf_set_next(state_buf, int, MDS_COLOUR_VARS_VERSION);
+  buf_set_next(state_buf, int, connected);
+  buf_set_next(state_buf, uint32_t, message_id);
+  mds_message_marshal(&received, state_buf);
+  
+  mds_message_destroy(&received);
+  return 0;
+}
+
+
+/**
+ * Unmarshal server implementation specific data and update the servers state accordingly
+ * 
+ * On critical failure the program should `abort()` or exit by other means.
+ * That is, do not let `reexec_failure_recover` run successfully, if it unrecoverable
+ * error has occurred or one severe enough that it is better to simply respawn.
+ * 
+ * @param   state_buf  The marshalled data that as not been read already
+ * @return             Non-zero on error
+ */
+int unmarshal_server(char* state_buf)
+{
+  /* buf_get_next(state_buf, int, MDS_COLOUR_VARS_VERSION); */
+  buf_next(state_buf, int, 1);
+  buf_get_next(state_buf, int, connected);
+  buf_get_next(state_buf, uint32_t, message_id);
+  fail_if (mds_message_unmarshal(&received, state_buf));
+  return 0;
+ fail:
+  xperror(*argv);
+  mds_message_destroy(&received);
+  return -1;
+}
+
+
+/**
+ * Attempt to recover from a re-exec failure that has been
+ * detected after the server successfully updated it execution image
+ * 
+ * @return  Non-zero on error
+ */
+int __attribute__((const)) reexec_failure_recover(void)
+{
+  return -1;
+}
+
+
+/**
+ * Perform the server's mission
+ * 
+ * @return  Non-zero on error
+ */
+int master_loop(void)
+{
+  int rc = 1, r;
+  
+  while (!reexecing && !terminating)
+    {
+      if (danger)
+	{
+	  danger = 0;
+	  free(send_buffer), send_buffer = NULL;
+	  send_buffer_size = 0;
+	}
+      
+      if (r = mds_message_read(&received, socket_fd), r == 0)
+	if (r = handle_message(), r == 0)
+	  continue;
+      
+      if (r == -2)
+	{
+	  eprint("corrupt message received, aborting.");
+	  goto done;
+	}
+      else if (errno == EINTR)
+	continue;
+      else
+	fail_if (errno != ECONNRESET);
+      
+      eprint("lost connection to server.");
+      mds_message_destroy(&received);
+      mds_message_initialise(&received);
+      connected = 0;
+      fail_if (reconnect_to_display());
+      connected = 1;
+    }
+  
+  rc = 0;
+  goto done;
+ fail:
+  xperror(*argv);
+ done:
+  if (rc || !reexecing)
+    mds_message_destroy(&received);
+  free(send_buffer);
+  return rc;
+}
+
+
+/**
+ * Handle the received message
+ * 
+ * @return  Zero on success, -1 on error
+ */
+int handle_message(void)
+{
+}
+
+
+/**
+ * Send a full message even if interrupted
+ * 
+ * @param   message  The message to send
+ * @param   length   The length of the message
+ * @return           Zero on success, -1 on error
+ */
+int full_send(const char* message, size_t length)
+{
+  size_t sent;
+  
+  while (length > 0)
+    {
+      sent = send_message(socket_fd, message, length);
+      if (sent > length)
+	{
+	  eprint("Sent more of a message than exists in the message, aborting.");
+	  return -1;
+	}
+      else
+	fail_if ((sent < length) && (errno != EINTR));
+      message += sent;
+      length -= sent;
+    }
+  return 0;
+ fail:
+  xperror(*argv);
+  return -1;
+}
+
+
+/**
+ * This function is called when a signal that
+ * signals that the system to dump state information
+ * and statistics has been received
+ * 
+ * @param  signo  The signal that has been received
+ */
+void received_info(int signo)
+{
+  (void) signo;
+  iprintf("next message ID: %" PRIu32, message_id);
+  iprintf("connected: %s", connected ? "yes" : "no");
+  iprintf("send buffer size: %zu bytes", send_buffer_size);
+}
+