afm-user-daemon: comments

Change-Id: I464404029c3ef4a1572a48d67d370aec529e8b3b
Signed-off-by: José Bollo <jose.bollo@iot.bzh>

1 files changed, 192 insertions, 73 deletions

diff --git a/src/afm-user-daemon.c b/src/afm-user-daemon.c
index 04f5fea..2615cf5 100644
--- a/src/afm-user-daemon.c
+++ b/src/afm-user-daemon.c
@@ -32,25 +32,30 @@
 #include "afm-launch-mode.h"
 #include "afm-run.h"
 
+/*
+ * name of the application
+ */
 static const char appname[] = "afm-user-daemon";
 
-static void usage()
-{
-	printf(
-		"usage: %s [-q] [-v] [-m mode] [-r rootdir]... [-a appdir]...\n"
-		"\n"
-		"   -a appdir    adds an application directory\n"
-		"   -r rootdir   adds a root directory of applications\n"
-		"   -m mode      set default launch mode (local or remote)\n"
-		"   -d           run as a daemon\n"
-		"   -q           quiet\n"
-		"   -v           verbose\n"
-		"\n",
-		appname
-	);
-}
+/*
+ * string for printing usage
+ */
+static const char usagestr[] =
+	"usage: %s [-q] [-v] [-m mode] [-r rootdir]... [-a appdir]...\n"
+	"\n"
+	"   -a appdir    adds an application directory\n"
+	"   -r rootdir   adds a root directory of applications\n"
+	"   -m mode      set default launch mode (local or remote)\n"
+	"   -d           run as a daemon\n"
+	"   -q           quiet\n"
+	"   -v           verbose\n"
+	"\n";
 
-static struct option options[] = {
+/*
+ * Option definition for getopt_long
+ */
+static const char options_s[] = "hdqvr:a:m:";
+static struct option options_l[] = {
 	{ "root",        required_argument, NULL, 'r' },
 	{ "application", required_argument, NULL, 'a' },
 	{ "mode",        required_argument, NULL, 'm' },
@@ -61,26 +66,60 @@ static struct option options[] = {
 	{ NULL, 0, NULL, 0 }
 };
 
+/*
+ * Connections to D-Bus
+ * This is an array for using the function
+ *    jbus_read_write_dispatch_multiple
+ * directly without transformations.
+ */
 static struct jbus *jbuses[2];
+#define system_bus  jbuses[0]
+#define user_bus    jbuses[1]
+
+/*
+ * Handle to the database of applications
+ */
 static struct afm_db *afdb;
 
+/*
+ * Returned error strings
+ */
 const char error_nothing[] = "[]";
 const char error_bad_request[] = "\"bad request\"";
 const char error_not_found[] = "\"not found\"";
 const char error_cant_start[] = "\"can't start\"";
 const char error_system[] = "\"system error\"";
 
-static const char *getappid(struct json_object *obj)
-{
-	return json_type_string == json_object_get_type(obj) ? json_object_get_string(obj) : NULL;
-}
 
-static int getrunid(struct json_object *obj)
+/*
+ * retrieves the 'runid' in 'obj' parameters received with the
+ * request 'jreq' for the 'method'.
+ *
+ * Returns 1 in case of success.
+ * Otherwise, if the 'runid' can't be retrived, an error stating
+ * the bad request is replied for 'jreq' and 0 is returned.
+ */
+static int onrunid(struct jreq *jreq, struct json_object *obj,
+						const char *method, int *runid)
 {
-	return json_type_int == json_object_get_type(obj) ? json_object_get_int(obj) : 0;
+	if (!j_read_integer(obj, runid)
+				&& !j_read_integer_at(obj, "runid", runid)) {
+		INFO("bad request method %s: %s", method,
+					json_object_to_json_string(obj));
+		jbus_reply_error_s(jreq, error_bad_request);
+		return 0;
+	}
+
+	INFO("method %s called for %d", method, *runid);
+	return 1;
 }
 
-static void reply(struct jreq *jreq, struct json_object *resp, const char *errstr)
+/*
+ * Sends the reply 'resp' to the request 'jreq' if 'resp' is not NULL.
+ * Otherwise, when 'resp' is NULL replies the error string 'errstr'.
+ */
+static void reply(struct jreq *jreq, struct json_object *resp,
+						const char *errstr)
 {
 	if (resp)
 		jbus_reply_j(jreq, resp);
@@ -88,14 +127,23 @@ static void reply(struct jreq *jreq, struct json_object *resp, const char *errst
 		jbus_reply_error_s(jreq, errstr);
 }
 
-static void reply_status(struct jreq *jreq, int status)
+/*
+ * Sends the reply "true" to the request 'jreq' if 'status' is zero.
+ * Otherwise, when 'status' is not zero replies the error string 'errstr'.
+ */
+static void reply_status(struct jreq *jreq, int status, const char *errstr)
 {
 	if (status)
-		jbus_reply_error_s(jreq, error_not_found);
+		jbus_reply_error_s(jreq, errstr);
 	else
 		jbus_reply_s(jreq, "true");
 }
 
+/*
+ * On query "runnables" from 'jreq' with parameters of 'obj'.
+ *
+ * Nothing is expected in 'obj' that can be anything.
+ */
 static void on_runnables(struct jreq *jreq, struct json_object *obj)
 {
 	struct json_object *resp;
@@ -105,17 +153,36 @@ static void on_runnables(struct jreq *jreq, struct json_object *obj)
 	json_object_put(resp);
 }
 
+/*
+ * On query "detail" from 'jreq' with parameters of 'obj'.
+ */
 static void on_detail(struct jreq *jreq, struct json_object *obj)
 {
 	const char *appid;
 	struct json_object *resp;
-	appid = getappid(obj);
+
+	/* get the parameters */
+	if (j_read_string(obj, &appid))
+		; /* appid as a string */
+	else if (j_read_string_at(obj, "id", &appid))
+		; /* appid as obj.id string */
+	else {
+		INFO("method detail called but bad request!");
+		jbus_reply_error_s(jreq, error_bad_request);
+		return;
+	}
+
+	/* wants details for appid */
 	INFO("method detail called for %s", appid);
 	resp = afm_db_get_application_public(afdb, appid);
 	reply(jreq, resp, error_not_found);
 	json_object_put(resp);
 }
 
+
+/*
+ * On query "start" from 'jreq' with parameters of 'obj'.
+ */
 static void on_start(struct jreq *jreq, struct json_object *obj)
 {
 	const char *appid, *modestr;
@@ -142,7 +209,8 @@ static void on_start(struct jreq *jreq, struct json_object *obj)
 	}
 
 	/* get the application */
-	INFO("method start called for %s mode=%s", appid, name_of_launch_mode(mode));
+	INFO("method start called for %s mode=%s", appid,
+						name_of_launch_mode(mode));
 	appli = afm_db_get_application(afdb, appid);
 	if (appli == NULL) {
 		jbus_reply_error_s(jreq, error_not_found);
@@ -168,43 +236,56 @@ static void on_start(struct jreq *jreq, struct json_object *obj)
 
 	/* returns the runid and its uri */
 	resp = json_object_new_object();
-	if (resp != NULL && j_add_integer(resp, "runid", runid) && j_add_string(resp, "uri", uri))
+	if (resp != NULL && j_add_integer(resp, "runid", runid)
+					&& j_add_string(resp, "uri", uri))
 		jbus_reply_j(jreq, resp);
 	else {
 		afm_run_stop(runid);
-		jbus_reply_error_s(jreq, error_cant_start);
+		jbus_reply_error_s(jreq, error_system);
 	}
 	json_object_put(resp);
 	free(uri);
 }
 
+/*
+ * On query "stop" from 'jreq' with parameters of 'obj'.
+ */
 static void on_stop(struct jreq *jreq, struct json_object *obj)
 {
 	int runid, status;
-	runid = getrunid(obj);
-	INFO("method stop called for %d", runid);
-	status = afm_run_stop(runid);
-	reply_status(jreq, status);
+	if (onrunid(jreq, obj, "stop", &runid)) {
+		status = afm_run_stop(runid);
+		reply_status(jreq, status, error_not_found);
+	}
 }
 
+/*
+ * On query "continue" from 'jreq' with parameters of 'obj'.
+ */
 static void on_continue(struct jreq *jreq, struct json_object *obj)
 {
 	int runid, status;
-	runid = getrunid(obj);
-	INFO("method continue called for %d", runid);
-	status = afm_run_continue(runid);
-	reply_status(jreq, status);
+	if (onrunid(jreq, obj, "continue", &runid)) {
+		status = afm_run_continue(runid);
+		reply_status(jreq, status, error_not_found);
+	}
 }
 
+/*
+ * On query "terminate" from 'jreq' with parameters of 'obj'.
+ */
 static void on_terminate(struct jreq *jreq, struct json_object *obj)
 {
 	int runid, status;
-	runid = getrunid(obj);
-	INFO("method terminate called for %d", runid);
-	status = afm_run_terminate(runid);
-	reply_status(jreq, status);
+	if (onrunid(jreq, obj, "terminate", &runid)) {
+		status = afm_run_terminate(runid);
+		reply_status(jreq, status, error_not_found);
+	}
 }
 
+/*
+ * On query "runners" from 'jreq' with parameters of 'obj'.
+ */
 static void on_runners(struct jreq *jreq, struct json_object *obj)
 {
 	struct json_object *resp;
@@ -214,22 +295,37 @@ static void on_runners(struct jreq *jreq, struct json_object *obj)
 	json_object_put(resp);
 }
 
+/*
+ * On query "state" from 'jreq' with parameters of 'obj'.
+ */
 static void on_state(struct jreq *jreq, struct json_object *obj)
 {
 	int runid;
 	struct json_object *resp;
-	runid = getrunid(obj);
-	INFO("method state called for %d", runid);
-	resp = afm_run_state(runid);
-	reply(jreq, resp, error_not_found);
-	json_object_put(resp);
+	if (onrunid(jreq, obj, "state", &runid)) {
+		resp = afm_run_state(runid);
+		reply(jreq, resp, error_not_found);
+		json_object_put(resp);
+	}
 }
 
+/*
+ * Calls the system daemon to achieve application management of
+ * the 'method' gotten from 'jreq' with the parameter's string 'msg'.
+ *
+ * The principle is very simple: call the corresponding system method
+ * and reply its response to the caller.
+ *
+ * The request and reply is synchronous and is blocking.
+ * It is possible to implment it in an asynchrounous way but it
+ * would brake the common behaviour. It would be a call like
+ * jbus_call_ss(system_bus, method, msg, callback, jreq)
+ */
 static void propagate(struct jreq *jreq, const char *msg, const char *method)
 {
 	char *reply;
 	INFO("method %s propagated with %s", method, msg);
-	reply = jbus_call_ss_sync(jbuses[0], method, msg);
+	reply = jbus_call_ss_sync(system_bus, method, msg);
 	if (reply) {
 		jbus_reply_s(jreq, reply);
 		free(reply);
@@ -238,24 +334,37 @@ static void propagate(struct jreq *jreq, const char *msg, const char *method)
 		jbus_reply_error_s(jreq, error_system);
 }
 
+/*
+ * On query "install" from 'jreq' with parameters of 'msg'.
+ */
 static void on_install(struct jreq *jreq, const char *msg)
 {
 	return propagate(jreq, msg, "install");
 }
 
+/*
+ * On query "uninstall" from 'jreq' with parameters of 'msg'.
+ */
 static void on_uninstall(struct jreq *jreq, const char *msg)
 {
 	return propagate(jreq, msg, "uninstall");
 }
 
+/*
+ * On system signaling that applications list changed
+ */
 static void on_signal_changed(struct json_object *obj)
 {
 	/* update the database */
 	afm_db_update_applications(afdb);
 	/* re-propagate now */
-	jbus_send_signal_j(jbuses[1], "changed", obj);
+	jbus_send_signal_j(user_bus, "changed", obj);
 }
 
+/*
+ * Tiny routine to daemonize the program
+ * Return 0 on success or -1 on failure.
+ */
 static int daemonize()
 {
 	int rc = fork();
@@ -266,6 +375,9 @@ static int daemonize()
 	return 0;
 }
 
+/*
+ * ENTRY POINT OF AFM-USER-DAEMON
+ */
 int main(int ac, char **av)
 {
 	int i, daemon = 0;
@@ -274,10 +386,10 @@ int main(int ac, char **av)
 	LOGAUTH(appname);
 
 	/* first interpretation of arguments */
-	while ((i = getopt_long(ac, av, "hdqvr:a:m:", options, NULL)) >= 0) {
+	while ((i = getopt_long(ac, av, options_s, options_l, NULL)) >= 0) {
 		switch (i) {
 		case 'h':
-			usage();
+			printf(usagestr, appname);
 			return 0;
 		case 'q':
 			if (verbosity)
@@ -332,7 +444,7 @@ int main(int ac, char **av)
 
 	/* second interpretation of arguments */
 	optind = 1;
-	while ((i = getopt_long(ac, av, "hdqvr:a:m:", options, NULL)) >= 0) {
+	while ((i = getopt_long(ac, av, options_s, options_l, NULL)) >= 0) {
 		switch (i) {
 		case 'r':
 			if (afm_db_add_root(afdb, optarg)) {
@@ -342,9 +454,9 @@ int main(int ac, char **av)
 			break;
 		case 'a':
 			if (afm_db_add_application(afdb, optarg)) {
-                                ERROR("can't add application %s", optarg);
-                                return 1;
-                        }
+				ERROR("can't add application %s", optarg);
+				return 1;
+			}
 			break;
 		}
 	}
@@ -355,47 +467,54 @@ int main(int ac, char **av)
 		return 1;
 	}
 
+	/* daemonize if requested */
 	if (daemon && daemonize()) {
 		ERROR("daemonization failed");
 		return 1;
 	}
 
-	/* init observers */
-	jbuses[0] = create_jbus_system(AFM_SYSTEM_DBUS_PATH);
-	if (!jbuses[0]) {
+	/* connects to the system bus */
+	system_bus = create_jbus_system(AFM_SYSTEM_DBUS_PATH);
+	if (!system_bus) {
 		ERROR("create_jbus failed for system");
 		return 1;
 	}
-	if(jbus_on_signal_j(jbuses[0], "changed", on_signal_changed)) {
+
+	/* observe signals of system */
+	if(jbus_on_signal_j(system_bus, "changed", on_signal_changed)) {
 		ERROR("adding signal observer failed");
 		return 1;
 	}
 
-	/* init service	*/
-	jbuses[1] = create_jbus_session(AFM_USER_DBUS_PATH);
-	if (!jbuses[1]) {
+	/* connect to the session bus */
+	user_bus = create_jbus_session(AFM_USER_DBUS_PATH);
+	if (!user_bus) {
 		ERROR("create_jbus failed");
 		return 1;
 	}
-	if(jbus_add_service_j(jbuses[1], "runnables", on_runnables)
-	|| jbus_add_service_j(jbuses[1], "detail", on_detail)
-	|| jbus_add_service_j(jbuses[1], "start", on_start)
-	|| jbus_add_service_j(jbuses[1], "terminate", on_terminate)
-	|| jbus_add_service_j(jbuses[1], "stop", on_stop)
-	|| jbus_add_service_j(jbuses[1], "continue", on_continue)
-	|| jbus_add_service_j(jbuses[1], "runners", on_runners)
-	|| jbus_add_service_j(jbuses[1], "state", on_state)
-	|| jbus_add_service_s(jbuses[1], "install", on_install)
-	|| jbus_add_service_s(jbuses[1], "uninstall", on_uninstall)) {
+
+	/* init services */
+	if (jbus_add_service_j(user_bus, "runnables", on_runnables)
+	 || jbus_add_service_j(user_bus, "detail",    on_detail)
+	 || jbus_add_service_j(user_bus, "start",     on_start)
+	 || jbus_add_service_j(user_bus, "terminate", on_terminate)
+	 || jbus_add_service_j(user_bus, "stop",      on_stop)
+	 || jbus_add_service_j(user_bus, "continue",  on_continue)
+	 || jbus_add_service_j(user_bus, "runners",   on_runners)
+	 || jbus_add_service_j(user_bus, "state",     on_state)
+	 || jbus_add_service_s(user_bus, "install",   on_install)
+	 || jbus_add_service_s(user_bus, "uninstall", on_uninstall)) {
 		ERROR("adding services failed");
 		return 1;
 	}
 
-	/* start and run */
-	if (jbus_start_serving(jbuses[1])) {
+	/* start servicing */
+	if (jbus_start_serving(user_bus)) {
 		ERROR("can't start server");
 		return 1;
 	}
+
+	/* run until error */
 	while (jbus_read_write_dispatch_multiple(jbuses, 2, -1, 20) >= 0);
 	return 0;
 }