[PATCH v2 07/10] shared/mainloop: Add mainloop_run_with_signal

[Luiz Augusto von Dentz <luiz.dentz@xxxxxxxxx>]

From: Luiz Augusto von Dentz <luiz.von.dentz@xxxxxxxxx>

This consolidates the handling of signalfd in similar ways as ELL does.
---
 src/shared/mainloop-glib.c   |  1 +
 src/shared/mainloop-notify.c | 81 ++++++++++++++++++++++++++++++++++++
 src/shared/mainloop.h        |  1 +
 3 files changed, 83 insertions(+)

diff --git a/src/shared/mainloop-glib.c b/src/shared/mainloop-glib.c
index 4403d02d8..a83c35482 100644
--- a/src/shared/mainloop-glib.c
+++ b/src/shared/mainloop-glib.c
@@ -37,6 +37,7 @@
 
 #include "mainloop.h"
 #include "mainloop-notify.h"
+#include "io.h"
 
 static GMainLoop *main_loop;
 static int exit_status;
diff --git a/src/shared/mainloop-notify.c b/src/shared/mainloop-notify.c
index 49ca4f6c9..81a2cef28 100644
--- a/src/shared/mainloop-notify.c
+++ b/src/shared/mainloop-notify.c
@@ -31,13 +31,17 @@
 #include <stdlib.h>
 #include <stddef.h>
 #include <string.h>
+#include <signal.h>
 
+#include <sys/signalfd.h>
 #include <sys/socket.h>
 #include <sys/un.h>
 
 #include "mainloop.h"
 #include "mainloop-notify.h"
 #include "timeout.h"
+#include "util.h"
+#include "io.h"
 
 #define WATCHDOG_TRIGGER_FREQ 2
 
@@ -46,6 +50,14 @@ static int notify_fd = -1;
 
 static unsigned int watchdog;
 
+struct signal_data {
+	struct io *io;
+	mainloop_signal_func func;
+	void *user_data;
+};
+
+static struct signal_data *signal_data;
+
 static bool watchdog_callback(void *user_data)
 {
 	mainloop_sd_notify("WATCHDOG=1");
@@ -129,3 +141,72 @@ int mainloop_sd_notify(const char *state)
 
 	return sendmsg(notify_fd, &msghdr, MSG_NOSIGNAL);
 }
+
+static bool signal_read(struct io *io, void *user_data)
+{
+	struct signal_data *data = user_data;
+	struct signalfd_siginfo si;
+	ssize_t result;
+	int fd;
+
+	fd = io_get_fd(io);
+
+	result = read(fd, &si, sizeof(si));
+	if (result != sizeof(si))
+		return false;
+
+	if (data && data->func)
+		data->func(si.ssi_signo, data->user_data);
+
+	return true;
+}
+
+static struct io *setup_signalfd(void)
+{
+	struct io *io;
+	sigset_t mask;
+	int fd;
+
+	sigemptyset(&mask);
+	sigaddset(&mask, SIGINT);
+	sigaddset(&mask, SIGTERM);
+	sigaddset(&mask, SIGUSR2);
+	sigaddset(&mask, SIGCHLD);
+
+	if (sigprocmask(SIG_BLOCK, &mask, NULL) < 0)
+		return NULL;
+
+	fd = signalfd(-1, &mask, SFD_NONBLOCK | SFD_CLOEXEC);
+	if (fd < 0)
+		return NULL;
+
+	io = io_new(fd);
+
+	io_set_close_on_destroy(io, true);
+	io_set_read_handler(io, signal_read, NULL, NULL);
+
+	return io;
+}
+
+int mainloop_run_with_signal(mainloop_signal_func func, void *user_data)
+{
+	struct io *io;
+	int ret;
+
+	if (!func)
+		return -EINVAL;
+
+	io = setup_signalfd();
+	if (!io)
+		return -errno;
+
+	signal_data = new0(struct signal_data, 1);
+	signal_data->io = io;
+
+	ret = mainloop_run();
+
+	io_destroy(io);
+	free(signal_data);
+
+	return ret;
+}
diff --git a/src/shared/mainloop.h b/src/shared/mainloop.h
index 73ed81187..1ede62797 100644
--- a/src/shared/mainloop.h
+++ b/src/shared/mainloop.h
@@ -36,6 +36,7 @@ void mainloop_quit(void);
 void mainloop_exit_success(void);
 void mainloop_exit_failure(void);
 int mainloop_run(void);
+int mainloop_run_with_signal(mainloop_signal_func func, void *user_data);
 
 int mainloop_add_fd(int fd, uint32_t events, mainloop_event_func callback,
 				void *user_data, mainloop_destroy_func destroy);
-- 
2.17.2