add spawning commands via pthread

CMakeLists.txt

@@ -5,7 +5,20 @@ find_package(PkgConfig REQUIRED)
 pkg_search_module(LIBINPUT REQUIRED libinput)
 pkg_search_module(LIBUDEV REQUIRED libudev)
 
+set(SPAWN PTHREAD CACHE STRING "Spawn method")
+set_property(CACHE SPAWN PROPERTY STRINGS PTHREAD FORK)
+
 add_executable(linuxflip main.c cli.c)
 target_compile_definitions(linuxflip PRIVATE LINUXFLIP_VERSION=${PROJECT_VERSION})
+if (NOT SPAWN)
+	set(SPAWN PTHREAD)
+endif()
+if (SPAWN STREQUAL "PTHREAD")
+	target_compile_definitions(linuxflip PRIVATE LINUXFLIP_SPAWN_PTHREAD=1)
+elseif(SPAWN STREQUAL "FORK")
+	target_compile_definitions(linuxflip PRIVATE LINUXFLIP_SPAWN_FORK=1)
+else()
+	message(FATAL_ERROR "invalid SPAWN option \"${SPAWN}\" (must be PTHREAD or FORK, or unset for default)")
+endif()
 target_include_directories(linuxflip PRIVATE ${LIBINPUT_INCLUDE_DIRS} ${LIBUDEV_INCLUDE_DIRS})
 target_link_libraries(linuxflip ${LIBINPUT_LIBRARIES} ${LIBUDEV_LIBRARIES})

main.c

@@ -1,3 +1,8 @@
+#if !defined(LINUXFLIP_SPAWN_PTHREAD) && !defined(LINUXFLIP_SPAWN_FORK)
+#warning "No spawn method; using default"
+#define LINUXFLIP_SPAWN_PTHREAD 1
+#endif
+
 #include <stdio.h>
 #include <errno.h>
 #include <string.h>
@@ -7,6 +12,9 @@
 #include <fcntl.h>
 #include <poll.h>
 #include <stdbool.h>
+#if LINUXFLIP_SPAWN_PTHREAD
+#include <pthread.h>
+#endif
 #include "cli.h"
 
 #define FATAL(...) {                                                                  \
@@ -27,14 +35,25 @@ static void close_restricted(int fd, void *user_data) {
 	close(fd);
 }
 
+static void* system_routine(void* command) {
+	system((const char*)command);
+	return 0;
+}
+
 int main(int argc, char *argv[]) {
 	if (argc >= 2 && strcmp(argv[1],"--help") == 0) {
 		print_help(argv[0], isatty(STDOUT_FILENO));
 		return 0;
 	}
 #ifdef LINUXFLIP_VERSION
 	if (argc >= 2 && strcmp(argv[1],"--version") == 0) {
-		printf("linuxflip %s\n", TO_STRING(LINUXFLIP_VERSION));
+		const char* spawn =
+#if LINUXFLIP_SPAWN_PTHREAD
+		"pthread";
+#else
+		"fork";
+#endif
+		printf("linuxflip %s (%s)\n", TO_STRING(LINUXFLIP_VERSION), spawn);
 		return 0;
 	}
 #endif
@@ -77,8 +96,14 @@ int main(int argc, char *argv[]) {
 			struct libinput_event_switch *switch_event = libinput_event_get_switch_event(event);
 			if (libinput_event_switch_get_switch(switch_event) != LIBINPUT_SWITCH_TABLET_MODE) continue;
 			const bool tablet_mode = libinput_event_switch_get_switch_state(switch_event) == LIBINPUT_SWITCH_STATE_ON;
+#if LINUXFLIP_SPAWN_PTHREAD
+			pthread_t thread;
+			pthread_create(&thread, NULL, system_routine, tablet_mode ? cmd_tablet : cmd_laptop);
+#else
 			if (!fork())
 				exit(system(tablet_mode ? cmd_tablet : cmd_laptop));
+#endif
+
 			libinput_event_destroy(event);
 		}
 	}