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/*
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)
{
(void) sig;
if (fuse_instance) {
fuse_session_exit(fuse_instance);
if(sig <= 0) {
fprintf(stderr, "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)
fprintf(stderr,
"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);
}
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