miraclectl: add scan commands

Three new commands that control scans on a given link are added:
 1) start-scan: Starts scanning in background for a given link
 2) stop-scan: Stops scanning in background for a given link
 3) scan: Does interactive scanning for a given link

The interactive scanning basically calls start-scan and stop-scan. In
between, it listens for dbus-signals for new peers and displays them if
they are assigned to the given link. This should be used for basic
p2p-device scanning on a link.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>

src/miraclectl.c

@@ -26,16 +26,120 @@
 #include <errno.h>
 #include <getopt.h>
 #include <locale.h>
+#include <signal.h>
 #include <stdbool.h>
 #include <stdlib.h>
 #include <string.h>
 #include <strings.h>
+#include <sys/signalfd.h>
 #include <systemd/sd-bus.h>
 #include "miracle.h"
 #include "shl_log.h"
 #include "shl_macro.h"
 #include "shl_util.h"
 
+/*
+ * Helpers for interactive commands
+ */
+
+static sd_bus *cli_bus;
+static sd_event *cli_event;
+static sd_event_source *cli_sigs[_NSIG];
+
+static int cli_signal_fn(sd_event_source *source,
+			 const struct signalfd_siginfo *ssi,
+			 void *data)
+{
+	if (ssi->ssi_signo == SIGCHLD) {
+		log_debug("caught SIGCHLD for %d", (int)ssi->ssi_pid);
+		return 0;
+	}
+
+	log_notice("caught signal %d, exiting..", (int)ssi->ssi_signo);
+	sd_event_exit(cli_event, 0);
+
+	return 0;
+}
+
+static void cli_destroy(void)
+{
+	unsigned int i;
+
+	if (!cli_bus)
+		return;
+
+	for (i = 0; cli_sigs[i]; ++i) {
+		sd_event_source_unref(cli_sigs[i]);
+		cli_sigs[i] = NULL;
+	}
+
+	sd_event_unref(cli_event);
+	cli_event = NULL;
+	sd_bus_unref(cli_bus);
+	cli_bus = NULL;
+}
+
+static int cli_init(sd_bus *bus)
+{
+	static const int sigs[] = {
+		SIGINT, SIGTERM, SIGQUIT, SIGHUP, SIGPIPE, SIGCHLD, 0
+	};
+	unsigned int i;
+	sigset_t mask;
+	int r;
+
+	if (cli_bus || !bus)
+		return log_EINVAL();
+
+	cli_bus = sd_bus_ref(bus);
+
+	r = sd_event_default(&cli_event);
+	if (r < 0) {
+		log_vERR(r);
+		goto error;
+	}
+
+	r = sd_bus_attach_event(cli_bus, cli_event, 0);
+	if (r < 0) {
+		log_vERR(r);
+		goto error;
+	}
+
+	for (i = 0; sigs[i]; ++i) {
+		sigemptyset(&mask);
+		sigaddset(&mask, sigs[i]);
+		sigprocmask(SIG_BLOCK, &mask, NULL);
+
+		r = sd_event_add_signal(cli_event,
+					sigs[i],
+					cli_signal_fn,
+					NULL,
+					&cli_sigs[i]);
+		if (r < 0) {
+			log_vERR(r);
+			goto error;
+		}
+	}
+
+	return 0;
+
+error:
+	cli_destroy();
+	return r;
+}
+
+static int cli_run(void)
+{
+	if (!cli_bus)
+		return log_EINVAL();
+
+	return sd_event_loop(cli_event);
+}
+
+/*
+ * verb: list
+ */
+
 static int verb_list_links(sd_bus *bus, sd_bus_message *m)
 {
 	char *link;
@@ -280,6 +384,10 @@ static int verb_list(sd_bus *bus, char **args, unsigned int n)
 	return 0;
 }
 
+/*
+ * verb: show-link
+ */
+
 static int verb_show_link(sd_bus *bus, char **args, unsigned int n)
 {
 	_cleanup_sd_bus_error_ sd_bus_error err = SD_BUS_ERROR_NULL;
@@ -375,6 +483,10 @@ static int verb_show_link(sd_bus *bus, char **args, unsigned int n)
 	return 0;
 }
 
+/*
+ * verb: show-peer
+ */
+
 static int verb_show_peer(sd_bus *bus, char **args, unsigned int n)
 {
 	_cleanup_sd_bus_error_ sd_bus_error err = SD_BUS_ERROR_NULL;
@@ -503,6 +615,10 @@ static int verb_show_peer(sd_bus *bus, char **args, unsigned int n)
 	return 0;
 }
 
+/*
+ * verb: add-link
+ */
+
 static int verb_add_link(sd_bus *bus, char **args, unsigned int n)
 {
 	_cleanup_sd_bus_error_ sd_bus_error err = SD_BUS_ERROR_NULL;
@@ -537,6 +653,10 @@ static int verb_add_link(sd_bus *bus, char **args, unsigned int n)
 	return 0;
 }
 
+/*
+ * verb: remove-link
+ */
+
 static int verb_remove_link(sd_bus *bus, char **args, unsigned int n)
 {
 	_cleanup_sd_bus_error_ sd_bus_error err = SD_BUS_ERROR_NULL;
@@ -560,6 +680,10 @@ static int verb_remove_link(sd_bus *bus, char **args, unsigned int n)
 	return 0;
 }
 
+/*
+ * verb: set-link-name
+ */
+
 static int verb_set_link_name(sd_bus *bus, char **args, unsigned int n)
 {
 	_cleanup_sd_bus_error_ sd_bus_error err = SD_BUS_ERROR_NULL;
@@ -612,6 +736,352 @@ static int verb_set_link_name(sd_bus *bus, char **args, unsigned int n)
 	return 0;
 }
 
+/*
+ * verb: start-scan
+ */
+
+static int verb_start_scan(sd_bus *bus, char **args, unsigned int n)
+{
+	_cleanup_sd_bus_error_ sd_bus_error err = SD_BUS_ERROR_NULL;
+	_cleanup_free_ char *path = NULL, *name = NULL;
+	int r;
+
+	name = sd_bus_label_escape(args[1]);
+	if (!name)
+		return log_ENOMEM();
+
+	path = shl_strcat("/org/freedesktop/miracle/link/", name);
+	if (!path)
+		return log_ENOMEM();
+
+	r = sd_bus_call_method(bus,
+			       "org.freedesktop.miracle",
+			       path,
+			       "org.freedesktop.miracle.Link",
+			       "StartScan",
+			       &err,
+			       NULL,
+			       NULL);
+	if (r < 0) {
+		log_error("cannot start scan on link %s: %s",
+			  args[1], bus_error_message(&err, r));
+		return r;
+	}
+
+	printf("Scan on link %s started\n", args[1]);
+	return 0;
+}
+
+/*
+ * verb: stop-scan
+ */
+
+static int verb_stop_scan(sd_bus *bus, char **args, unsigned int n)
+{
+	_cleanup_sd_bus_error_ sd_bus_error err = SD_BUS_ERROR_NULL;
+	_cleanup_free_ char *path = NULL, *name = NULL;
+	int r;
+
+	name = sd_bus_label_escape(args[1]);
+	if (!name)
+		return log_ENOMEM();
+
+	path = shl_strcat("/org/freedesktop/miracle/link/", name);
+	if (!path)
+		return log_ENOMEM();
+
+	r = sd_bus_call_method(bus,
+			       "org.freedesktop.miracle",
+			       path,
+			       "org.freedesktop.miracle.Link",
+			       "StopScan",
+			       &err,
+			       NULL,
+			       NULL);
+	if (r < 0) {
+		log_error("cannot stop scan on link %s: %s",
+			  args[1], bus_error_message(&err, r));
+		return r;
+	}
+
+	printf("Scan on link %s stopped\n", args[1]);
+	return 0;
+}
+
+/*
+ * verb: scan
+ */
+
+static int verb_scan_list_peer(sd_bus *bus,
+			       sd_bus_message *m,
+			       const char *link_filter,
+			       const char *peer)
+{
+	const char *obj, *link = NULL, *name = NULL;
+	int r, connected = false;
+
+	r = sd_bus_message_enter_container(m, 'a', "{sa{sv}}");
+	if (r < 0)
+		return log_bus_parser(r);
+
+	while ((r = sd_bus_message_enter_container(m,
+						   'e',
+						   "sa{sv}")) > 0) {
+		r = sd_bus_message_read(m, "s", &obj);
+		if (r < 0)
+			return log_bus_parser(r);
+
+		if (strcmp(obj, "org.freedesktop.miracle.Peer")) {
+			r = sd_bus_message_skip(m, "a{sv}");
+			if (r < 0)
+				return log_bus_parser(r);
+			r = sd_bus_message_exit_container(m);
+			if (r < 0)
+				return log_bus_parser(r);
+			continue;
+		}
+
+		r = sd_bus_message_enter_container(m, 'a', "{sv}");
+		if (r < 0)
+			return log_bus_parser(r);
+
+		while ((r = sd_bus_message_enter_container(m,
+							   'e',
+							   "sv")) > 0) {
+			r = sd_bus_message_read(m, "s", &obj);
+			if (r < 0)
+				return log_bus_parser(r);
+
+			if (!strcmp(obj, "Link")) {
+				r = bus_message_read_basic_variant(m, "o",
+								   &obj);
+				if (r < 0)
+					return log_bus_parser(r);
+
+				obj = shl_startswith(obj,
+					"/org/freedesktop/miracle/link/");
+				if (obj)
+					link = obj;
+			} else if (!strcmp(obj, "Name")) {
+				r = bus_message_read_basic_variant(m, "s",
+								   &name);
+				if (r < 0)
+					return log_bus_parser(r);
+			} else if (!strcmp(obj, "Connected")) {
+				r = bus_message_read_basic_variant(m, "b",
+								   &connected);
+				if (r < 0)
+					return log_bus_parser(r);
+			} else {
+				sd_bus_message_skip(m, "v");
+			}
+
+			r = sd_bus_message_exit_container(m);
+			if (r < 0)
+				return log_bus_parser(r);
+		}
+		if (r < 0)
+			return log_bus_parser(r);
+
+		r = sd_bus_message_exit_container(m);
+		if (r < 0)
+			return log_bus_parser(r);
+
+		r = sd_bus_message_exit_container(m);
+		if (r < 0)
+			return log_bus_parser(r);
+	}
+	if (r < 0)
+		return log_bus_parser(r);
+
+	r = sd_bus_message_exit_container(m);
+	if (r < 0)
+		return log_bus_parser(r);
+
+	if (!strcmp(link, link_filter))
+		printf("%4s %-24s %-4s\n",
+		       peer, name, connected ? "yes" : "no");
+
+	return 0;
+}
+
+static int verb_scan_list(sd_bus *bus, const char *link)
+{
+	_cleanup_sd_bus_message_ sd_bus_message *m = NULL;
+	_cleanup_sd_bus_error_ sd_bus_error err = SD_BUS_ERROR_NULL;
+	_cleanup_free_ char *peer = NULL;
+	const char *obj;
+	int r;
+
+	r = sd_bus_call_method(bus,
+			       "org.freedesktop.miracle",
+			       "/org/freedesktop/miracle",
+			       "org.freedesktop.DBus.ObjectManager",
+			       "GetManagedObjects",
+			       &err,
+			       &m,
+			       "");
+	if (r < 0) {
+		log_error("cannot retrieve objects: %s",
+			  bus_error_message(&err, r));
+		return r;
+	}
+
+	r = sd_bus_message_enter_container(m, 'a', "{oa{sa{sv}}}");
+	if (r < 0)
+		return log_bus_parser(r);
+
+	while ((r = sd_bus_message_enter_container(m,
+						   'e',
+						   "oa{sa{sv}}")) > 0) {
+		r = sd_bus_message_read(m, "o", &obj);
+		if (r < 0)
+			return log_bus_parser(r);
+
+		obj = shl_startswith(obj, "/org/freedesktop/miracle/peer/");
+		if (!obj) {
+			r = sd_bus_message_skip(m, "a{sa{sv}}");
+			if (r < 0)
+				return log_bus_parser(r);
+			r = sd_bus_message_exit_container(m);
+			if (r < 0)
+				return log_bus_parser(r);
+			continue;
+		}
+
+		free(peer);
+		peer = sd_bus_label_unescape(obj);
+		if (!peer)
+			return log_ENOMEM();
+
+		r = verb_scan_list_peer(bus, m, link, peer);
+		if (r < 0)
+			return r;
+
+		r = sd_bus_message_exit_container(m);
+		if (r < 0)
+			return log_bus_parser(r);
+	}
+	if (r < 0)
+		return log_bus_parser(r);
+
+	r = sd_bus_message_exit_container(m);
+	if (r < 0)
+		return log_bus_parser(r);
+
+	return 0;
+}
+
+static int verb_scan_match_fn(sd_bus *bus,
+			      sd_bus_message *m,
+			      void *data,
+			      sd_bus_error *err)
+{
+	_cleanup_free_ char *peer = NULL;
+	const char *obj, *link = data;
+	int r;
+
+	r = sd_bus_message_read(m, "o", &obj);
+	if (r < 0)
+		return log_bus_parser(r);
+
+	obj = shl_startswith(obj, "/org/freedesktop/miracle/peer/");
+	if (!obj)
+		return 0;
+
+	peer = sd_bus_label_unescape(obj);
+	if (!peer)
+		return log_ENOMEM();
+
+	r = verb_scan_list_peer(bus, m, link, peer);
+	if (r < 0)
+		return r;
+
+	return 0;
+}
+
+static void verb_scan_listen(sd_bus *bus, const char *link)
+{
+	int r;
+
+	r = sd_bus_add_match(bus,
+			     "type='signal',"
+			     "sender='org.freedesktop.miracle',"
+			     "interface='org.freedesktop.DBus.ObjectManager',"
+			     "member='InterfacesAdded'",
+			     verb_scan_match_fn,
+			     (void*)link);
+	if (r < 0)
+		return log_error("cannot add dbus match: %d", r);
+
+	r = cli_init(bus);
+	if (r < 0)
+		goto error;
+
+	verb_scan_list(bus, link);
+	cli_run();
+
+error:
+	cli_destroy();
+	sd_bus_remove_match(bus,
+			    "type='signal',"
+			    "sender='org.freedesktop.miracle',"
+			    "interface='org.freedesktop.DBus.ObjectManager'",
+			    verb_scan_match_fn,
+			    NULL);
+}
+
+static int verb_scan(sd_bus *bus, char **args, unsigned int n)
+{
+	_cleanup_sd_bus_error_ sd_bus_error err = SD_BUS_ERROR_NULL;
+	_cleanup_free_ char *path = NULL, *name = NULL;
+	int r;
+
+	name = sd_bus_label_escape(args[1]);
+	if (!name)
+		return log_ENOMEM();
+
+	path = shl_strcat("/org/freedesktop/miracle/link/", name);
+	if (!path)
+		return log_ENOMEM();
+
+	r = sd_bus_call_method(bus,
+			       "org.freedesktop.miracle",
+			       path,
+			       "org.freedesktop.miracle.Link",
+			       "StartScan",
+			       &err,
+			       NULL,
+			       NULL);
+	if (r < 0)
+		log_warning("cannot start scan on link %s (already running?): %s",
+			    args[1], bus_error_message(&err, r));
+
+	printf("Scan on link %s started, listing peers..\n", args[1]);
+	printf("%4s %-24s %-4s\n", "ID", "NAME", "CONNECTED");
+	verb_scan_listen(bus, name);
+
+	r = sd_bus_call_method(bus,
+			       "org.freedesktop.miracle",
+			       path,
+			       "org.freedesktop.miracle.Link",
+			       "StopScan",
+			       &err,
+			       NULL,
+			       NULL);
+	if (r < 0)
+		log_error("cannot stop scan on link %s: %s",
+			  args[1], bus_error_message(&err, r));
+	else
+		printf("Scan on link %s stopped\n", args[1]);
+
+	return 0;
+}
+
+/*
+ * main
+ */
+
 static int help(void)
 {
 	/*
@@ -632,6 +1102,9 @@ static int help(void)
 	       "  add-link LINK...                Start managing the given link\n"
 	       "  remove-link LINK...             Stop managing the given link\n"
 	       "  set-link-name LINK NAME         Set friendly-name of given link\n"
+	       "  start-scan LINK...              Start peer discovery on given link\n"
+	       "  stop-scan LINK...               Stop peer discovery on given link\n"
+	       "  scan LINK...                    Interactive scan on given link\n"
 	       , program_invocation_short_name);
 	/*
 	 * 80-char barrier:
@@ -696,6 +1169,9 @@ static int miraclectl_main(sd_bus *bus, int argc, char *argv[])
 		{ "add-link",		EQUAL,	3,	verb_add_link },
 		{ "remove-link",	EQUAL,	2,	verb_remove_link },
 		{ "set-link-name",	EQUAL,	3,	verb_set_link_name },
+		{ "start-scan",		EQUAL,	2,	verb_start_scan },
+		{ "stop-scan",		EQUAL,	2,	verb_stop_scan },
+		{ "scan",		EQUAL,	2,	verb_scan },
 	};
 	int left;
 	unsigned int i;