Send READY=1 notification to systemd after tee-supplicant is setup

This option is very useful when tee-supplicant is started from systemd and can used with Type=notify to signal readiness

tee-supplicant/CMakeLists.txt

@@ -102,11 +102,9 @@ target_link_libraries(${PROJECT_NAME}
 	PRIVATE teec
 )
 
-if(CFG_TEE_SUPP_PLUGINS)
-	target_link_libraries(${PROJECT_NAME}
-		PRIVATE dl
-	)
-endif()
+target_link_libraries(${PROJECT_NAME}
+	PRIVATE dl
+)
 
 ################################################################################
 # Install targets

tee-supplicant/Makefile

@@ -74,10 +74,11 @@ TEES_LFLAGS	+= -lpthread
 # Needed to get clock_gettime() for for glibc versions before 2.17
 TEES_LFLAGS	+= -lrt
 
+# Needed for dlopen()
+TEES_LFLAGS	+= -ldl
+
 ifeq ($(CFG_TEE_SUPP_PLUGINS),y)
 # Needed to dynamically load user plugins
-TEES_LFLAGS	+= -ldl
-# Needed for dlopen()
 TEES_LFLAGS 	+= -Wl,-rpath=$(CFG_TEE_PLUGIN_LOAD_PATH)
 endif
 

tee-supplicant/src/tee_supplicant.c

@@ -54,6 +54,7 @@
 #include <tee_supp_fs.h>
 #include <tee_supplicant.h>
 #include <unistd.h>
+#include <dlfcn.h>
 
 #include "optee_msg_supplicant.h"
 
@@ -823,6 +824,8 @@ int main(int argc, char *argv[])
 	int e = 0;
 	int long_index = 0;
 	int opt = 0;
+	void *sd_handle = NULL;
+	int (*tee_sd_notify)(int unset_environment, const char *state) =  NULL;
 
 	e = pthread_mutex_init(&arg.mutex, NULL);
 	if (e) {
@@ -923,6 +926,20 @@ int main(int argc, char *argv[])
 		}
 	}
 
+	/* we are set here notify systemd */
+	sd_handle = dlopen("libsystemd.so.0", RTLD_LAZY);
+	if (sd_handle) {
+		tee_sd_notify = dlsym(sd_handle, "sd_notify");
+		if (tee_sd_notify) {
+				e = tee_sd_notify(0, "READY=1");
+				if (e <= 0)
+					fprintf(stderr, "sd_notify failed: %d\n", e);
+		} else
+			fprintf(stderr, "Couldn't find sd_notify symbol: %s\n", dlerror());
+		dlclose(sd_handle);
+	} else
+		fprintf(stderr, "Couldn't open libsystemd.so.0: %s\n", dlerror());	
+
 	if (daemonize) {
 		/* Release parent */
 		if (write(pipefd[1], "", 1) != 1) {