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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 "qemu/osdep.h"
#include "fuse_i.h"
#include "fuse_lowlevel.h"
#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.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) {
fuse_log(FUSE_LOG_ERR, "fuse: cannot get old signal handler: %s\n",
strerror(errno));
return -1;
}
if (old_sa.sa_handler == (remove ? handler : SIG_DFL) &&
sigaction(sig, &sa, NULL) == -1) {
fuse_log(FUSE_LOG_ERR, "fuse: cannot set signal handler: %s\n",
strerror(errno));
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);
}
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