1 files changed, 91 insertions, 0 deletions
diff --git a/tools/virtiofsd/fuse_signals.c b/tools/virtiofsd/fuse_signals.c
new file mode 100644
index 0000000000..4271947bd4
--- /dev/null
+++ b/tools/virtiofsd/fuse_signals.c
@@ -0,0 +1,91 @@
+/*
+  FUSE: Filesystem in Userspace
+  Copyright (C) 2001-2007  Miklos Szeredi <miklos@szeredi.hu>
+
+  Utility functions for setting signal handlers.
+
+  This program can be distributed under the terms of the GNU LGPLv2.
+  See the file COPYING.LIB
+*/
+
+#include "config.h"
+#include "fuse_lowlevel.h"
+#include "fuse_i.h"
+
+#include <stdio.h>
+#include <string.h>
+#include <signal.h>
+#include <stdlib.h>
+
+static struct fuse_session *fuse_instance;
+
+static void exit_handler(int sig)
+{
+	if (fuse_instance) {
+		fuse_session_exit(fuse_instance);
+		if(sig <= 0) {
+			fuse_log(FUSE_LOG_ERR, "assertion error: signal value <= 0\n");
+			abort();
+		}
+		fuse_instance->error = sig;
+	}
+}
+
+static void do_nothing(int sig)
+{
+	(void) sig;
+}
+
+static int set_one_signal_handler(int sig, void (*handler)(int), int remove)
+{
+	struct sigaction sa;
+	struct sigaction old_sa;
+
+	memset(&sa, 0, sizeof(struct sigaction));
+	sa.sa_handler = remove ? SIG_DFL : handler;
+	sigemptyset(&(sa.sa_mask));
+	sa.sa_flags = 0;
+
+	if (sigaction(sig, NULL, &old_sa) == -1) {
+		perror("fuse: cannot get old signal handler");
+		return -1;
+	}
+
+	if (old_sa.sa_handler == (remove ? handler : SIG_DFL) &&
+	    sigaction(sig, &sa, NULL) == -1) {
+		perror("fuse: cannot set signal handler");
+		return -1;
+	}
+	return 0;
+}
+
+int fuse_set_signal_handlers(struct fuse_session *se)
+{
+	/* If we used SIG_IGN instead of the do_nothing function,
+	   then we would be unable to tell if we set SIG_IGN (and
+	   thus should reset to SIG_DFL in fuse_remove_signal_handlers)
+	   or if it was already set to SIG_IGN (and should be left
+	   untouched. */
+	if (set_one_signal_handler(SIGHUP, exit_handler, 0) == -1 ||
+	    set_one_signal_handler(SIGINT, exit_handler, 0) == -1 ||
+	    set_one_signal_handler(SIGTERM, exit_handler, 0) == -1 ||
+	    set_one_signal_handler(SIGPIPE, do_nothing, 0) == -1)
+		return -1;
+
+	fuse_instance = se;
+	return 0;
+}
+
+void fuse_remove_signal_handlers(struct fuse_session *se)
+{
+	if (fuse_instance != se)
+		fuse_log(FUSE_LOG_ERR,
+			"fuse: fuse_remove_signal_handlers: unknown session\n");
+	else
+		fuse_instance = NULL;
+
+	set_one_signal_handler(SIGHUP, exit_handler, 1);
+	set_one_signal_handler(SIGINT, exit_handler, 1);
+	set_one_signal_handler(SIGTERM, exit_handler, 1);
+	set_one_signal_handler(SIGPIPE, do_nothing, 1);
+}