beginning of echo server

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

5 files changed, 336 insertions, 3 deletions

diff --git a/Makefile b/Makefile
index ec70381..1a3c248 100644
--- a/Makefile
+++ b/Makefile
@@ -72,11 +72,14 @@ C_FLAGS = $(OPTIMISE) $(WARN) -std=$(STD) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS)  \
 # Object files for the libary
 LIBOBJ = linked-list hash-table fd-table mds-message util
 
+# Servers and utilities.
+SERVERS = mds mds-respawn mds-server mds-echo
+
 
 # Build rules.
 
 .PHONY: all
-all: obj/mds-base.o bin/mds bin/mds-respawn bin/mds-server bin/libmdsserver.so
+all: obj/mds-base.o $(foreach S,$(SERVERS),bin/$(S)) bin/libmdsserver.so
 
 
 MDS_SERVER_OBJ_ = mds-server interception-condition client multicast  \
@@ -94,7 +97,7 @@ endif
 
 bin/%: obj/%.o obj/mds-base.o bin/libmdsserver.so
 	mkdir -p $(shell dirname $@)
-	$(CC) $(C_FLAGS) -o $@ $(LDS) $< obj/mds-base.o
+	$(CC) $(C_FLAGS) -o $@ $(LDS) $(LDS_$*) $< obj/mds-base.o
 
 bin/mds: obj/mds.o bin/libmdsserver.so
 	mkdir -p $(shell dirname $@)
diff --git a/TODO b/TODO
new file mode 100644
index 0000000..6515768
--- /dev/null
+++ b/TODO
@@ -0,0 +1,26 @@
+Missing servers:
+
+	xmds		Translation from X to mds
+	wmds		Translation from Wayland to mds
+	mmds		Translation from Mir to mds
+	mdsx		Translation from mds to X
+	mdsw		Translation from mds to Wayland
+	mdsm		Translation from mds to Mir
+	hwgamma		Hardware implementation of gamma ramps
+	swgamma		Software implementation of gamma ramps
+	hwcursor	Hardware cursor
+	swcursor	Software cursor
+	cursorgamma	Fixes gamma ramps for cursors
+	coopgamma	Enables multiple gamma servers
+	inet		Network enabled display server
+	remote		Bind to a remote display server
+	fb		Framebuffer presenter
+	clipboard	Clipboard
+	kkbd		Keyboard input from kernel
+	kbd		Keyboard input
+	rat		Rat input
+	compositor	Composites the display
+	crtc		CRTC identifier
+	seat		Seat sandboxing
+	dri		DRI output
+
diff --git a/src/mds-echo.c b/src/mds-echo.c
new file mode 100644
index 0000000..7b1a0ac
--- /dev/null
+++ b/src/mds-echo.c
@@ -0,0 +1,262 @@
+/**
+ * mds — A micro-display server
+ * Copyright © 2014  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-echo.h"
+
+#include <libmdsserver/macros.h>
+#include <libmdsserver/util.h>
+#include <libmdsserver/mds-message.h>
+
+#include <errno.h>
+#include <stdint.h>
+#include <string.h>
+#include <stdio.h>
+#define reconnect_to_display() -1 /* TODO */
+
+
+
+#define MDS_ECHO_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 = 1,
+    .sanity_check_argc = 1
+  };
+
+
+
+/**
+ * Value of the ‘Message ID’ header for the next message
+ */
+static int32_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;
+
+
+
+/**
+ * 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)
+{
+  const char* message =
+    "Command: intercept\n"
+    "Message ID: 0\n"
+    "Length: 13\n"
+    "\n"
+    "Command: echo";
+  size_t length = strlen(message);
+  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 if ((sent < length) && (errno != EINTR))
+	{
+	  perror(*argv);
+	  return 1;
+	}
+      message += sent;
+      length -= sent;
+    }
+  
+  mds_message_initialise(&received);
+  return 0;
+}
+
+
+/**
+ * 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;
+  
+  if (reconnect_to_display())
+    {
+      mds_message_destroy(&received);
+      return 1;
+    }
+  connected = 1;
+  return 0;
+}
+
+
+/**
+ * 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(int32_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_ECHO_VARS_VERSION);
+  buf_set_next(state_buf, int, connected);
+  buf_set_next(state_buf, int32_t, message_id);
+  mds_message_marshal(&received, state_buf);
+  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)
+{
+  int r;
+  /* buf_get_next(state_buf, int, MDS_ECHO_VARS_VERSION); */
+  buf_next(state_buf, int, 1);
+  buf_get_next(state_buf, int, connected);
+  buf_get_next(state_buf, int32_t, message_id);
+  r = mds_message_unmarshal(&received, state_buf);
+  if (r)
+    mds_message_destroy(&received);
+  return r;
+}
+
+
+/**
+ * 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)
+{
+  while (!reexecing && !terminating)
+    {
+      int r = mds_message_read(&received, socket_fd);
+      if (r == 0)
+	{
+	  r = echo_message();
+	  if (r == 0)
+	    continue;
+	}
+      if (r == -2)
+	{
+	  eprint("corrupt message received, aborting.");
+	  goto fail;
+	}
+      else if (errno == EINTR)
+	continue;
+      else if (errno != ECONNRESET)
+	goto pfail;
+      
+      eprint("lost connection to server.");
+      mds_message_destroy(&received);
+      mds_message_initialise(&received);
+      connected = 0;
+      if (reconnect_to_display())
+	goto fail;
+      connected = 1;
+    }
+  
+  mds_message_destroy(&received);
+  return 0;
+ pfail:
+  perror(*argv);
+ fail:
+  mds_message_destroy(&received);
+  return 1;
+}
+
+
+/**
+ * Echo the received message payload
+ * 
+ * @return  Zero on success -1 on error or interruption,
+ *          errno will be set accordingly
+ */
+int echo_message(void)
+{
+  return 0; /* TODO */
+}
+
diff --git a/src/mds-echo.h b/src/mds-echo.h
new file mode 100644
index 0000000..83a6495
--- /dev/null
+++ b/src/mds-echo.h
@@ -0,0 +1,40 @@
+/**
+ * mds — A micro-display server
+ * Copyright © 2014  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/>.
+ */
+#ifndef MDS_MDS_ECHO_H
+#define MDS_MDS_ECHO_H
+
+
+#include "mds-base.h"
+
+
+/**
+ * Echo the received message
+ * 
+ * @return  Non-zero on error or interruption, errno will be
+ *          set accordingly. Destroy the message on error,
+ *          be aware that the reading could have been
+ *          interrupted by a signal rather than canonical error.
+ *          If -2 is returned errno will not have been set,
+ *          -2 indicates that the message is malformated,
+ *          which is a state that cannot be recovered from.
+ */
+int echo_message(void);
+
+
+#endif
+
diff --git a/test.d/mdsinitrc b/test.d/mdsinitrc
index aaa52a6..0c1f75f 100755
--- a/test.d/mdsinitrc
+++ b/test.d/mdsinitrc
@@ -28,7 +28,9 @@ if [ -z "${XDG_CONFIG_HOME}" ]; then
 fi
 mds-respawn --interval=10 \
     { sleep 4s } \
-    { sleep 1m } &
+    { sleep 1m } \
+    { mds-echo } \
+    &
 if which terminator 2>/dev/null >&2; then
     exec terminator
 else