[Proof of concept] Interprocess communication support

configure.ac

@@ -152,6 +152,20 @@ AS_IF([test "x$enable_geoclue" != xno], [
 AM_CONDITIONAL([ENABLE_GEOCLUE], [test "x$enable_geoclue" = xyes])
 
 
+# Check for interprocess communication
+AC_MSG_CHECKING([whether to enable interprocess communication])
+AC_ARG_ENABLE([ipc], [AC_HELP_STRING([--enable-ipc],
+	[enable interprocess communication])],
+        [enable_ipc=$enableval],[enable_ipc=yes])
+AS_IF([test "x$enable_ipc" != xno], [
+        AC_MSG_RESULT([yes])
+], [
+        AC_MSG_RESULT([no])
+])
+AM_CONDITIONAL([ENABLE_IPC], [test "x$enable_ipc" = xyes])
+
+
+
 # Check for GUI status icon
 AC_MSG_CHECKING([whether to enable GUI status icon])
 AC_ARG_ENABLE([gui], [AC_HELP_STRING([--enable-gui],
@@ -243,6 +257,7 @@ echo "
     Location providers:
     Geoclue:		${enable_geoclue}
 
+    IPC:		${enable_ipc}
     GUI:		${enable_gui}
     Ubuntu icons:	${enable_ubuntu}
     systemd units:	${enable_systemd} ${systemduserunitdir}

src/Makefile.am

@@ -22,10 +22,13 @@ EXTRA_redshift_SOURCES = \
 	gamma-randr.c gamma-randr.h \
 	gamma-vidmode.c gamma-vidmode.h \
 	gamma-w32gdi.c gamma-w32gdi.h \
-	location-geoclue.c location-geoclue.h
+	location-geoclue.c location-geoclue.h \
+	server.c server.h \
+	service.c service.h
 
 AM_CFLAGS =
 redshift_LDADD = @LIBINTL@
+redshift_LDFLAGS =
 EXTRA_DIST =
 
 if ENABLE_DRM
@@ -63,3 +66,9 @@ AM_CFLAGS += $(GEOCLUE_CFLAGS) $(GEOCLUE_LIBS)
 redshift_LDADD += \
 	$(GEOCLUE_LIBS) $(GEOCLUE_CFLAGS)
 endif
+
+if ENABLE_IPC
+redshift_SOURCES += server.c server.h service.c service.h
+AM_CFLAGS += -DENABLE_IPC
+redshift_LDFLAGS += -pthread
+endif

src/ipc-client.py

@@ -0,0 +1,31 @@
+#!/usr/bin/env python3
+# Simple manual IPC client for debugging
+
+import os
+import socket
+import threading
+
+display = os.environ["DISPLAY"] if "DISPLAY" in os.environ else ""
+redshift_id = os.environ["REDSHIFT_ID"] if "REDSHIFT_ID" in os.environ else ""
+path = "/dev/shm/.redshift-socket-%i-%s:%s" % (os.getuid(), display, redshift_id)
+
+socket = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+socket.connect(path)
+
+def recv_loop():
+    got = socket.recv(1024)
+    if len(got) > 0:
+        print(got.decode("utf-8"));
+
+thread = threading.Thread(target = recv_loop)
+thread.setDaemon(True)
+thread.start()
+
+while True:
+    line = input()
+    if line == "":
+        break
+    socket.send((line + "\n").encode("utf-8"))
+
+socket.close()
+

src/redshift.c

@@ -76,6 +76,10 @@
 # include "location-geoclue.h"
 #endif
 
+#ifdef ENABLE_IPC
+# include "service.h"
+#endif
+
 
 /* Union of state data for gamma adjustment methods */
 typedef union {
@@ -263,6 +267,12 @@ static int disable = 0;
 #endif /* ! HAVE_SIGNAL_H || __WIN32__ */
 
 
+int temp_day = -1;
+int temp_night = -1;
+float brightness_day = NAN;
+float brightness_night = NAN;
+
+
 /* Print which period (night, day or transition) we're currently in. */
 static void
 print_period(double elevation)
@@ -661,11 +671,7 @@ main(int argc, char *argv[])
 	char *config_filepath = NULL;
 
 	int temp_set = -1;
-	int temp_day = -1;
-	int temp_night = -1;
 	float gamma[3] = { NAN, NAN, NAN };
-	float brightness_day = NAN;
-	float brightness_night = NAN;
 
 	const gamma_method_t *method = NULL;
 	char *method_args = NULL;
@@ -1220,6 +1226,9 @@ main(int argc, char *argv[])
 			printf("Status: %s\n", "Enabled");
 		}
 
+#ifdef ENABLE_IPC
+		service_start();
+#endif
 		/* Continuously adjust color temperature */
 		int done = 0;
 		int disabled = 0;
@@ -1254,6 +1263,10 @@ main(int argc, char *argv[])
 					   ongoing transition */
 					short_trans = 0;
 				} else {
+#ifdef ENABLE_IPC
+					service_close();
+#endif
+
 					if (!disabled) {
 						/* Make a short transition
 						   back to 6500K */