mirror of
https://github.com/topjohnwu/ndk-busybox.git
synced 2024-12-04 18:06:52 +00:00
385b4562e3
function old new delta dumpleases_main 632 623 -9 Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
78 lines
2.3 KiB
C
78 lines
2.3 KiB
C
/* vi: set sw=4 ts=4: */
|
|
/*
|
|
* Signal pipe infrastructure. A reliable way of delivering signals.
|
|
*
|
|
* Russ Dill <Russ.Dill@asu.edu> December 2003
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; either version 2 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
|
|
*/
|
|
#include "common.h"
|
|
|
|
/* Global variable: we access it from signal handler */
|
|
static struct fd_pair signal_pipe;
|
|
|
|
static void signal_handler(int sig)
|
|
{
|
|
unsigned char ch = sig; /* use char, avoid dealing with partial writes */
|
|
if (write(signal_pipe.wr, &ch, 1) != 1)
|
|
bb_perror_msg("can't send signal");
|
|
}
|
|
|
|
/* Call this before doing anything else. Sets up the socket pair
|
|
* and installs the signal handler */
|
|
void FAST_FUNC udhcp_sp_setup(void)
|
|
{
|
|
/* was socketpair, but it needs AF_UNIX in kernel */
|
|
xpiped_pair(signal_pipe);
|
|
close_on_exec_on(signal_pipe.rd);
|
|
close_on_exec_on(signal_pipe.wr);
|
|
ndelay_on(signal_pipe.wr);
|
|
bb_signals(0
|
|
+ (1 << SIGUSR1)
|
|
+ (1 << SIGUSR2)
|
|
+ (1 << SIGTERM)
|
|
, signal_handler);
|
|
}
|
|
|
|
/* Quick little function to setup the rfds. Will return the
|
|
* max_fd for use with select. Limited in that you can only pass
|
|
* one extra fd */
|
|
int FAST_FUNC udhcp_sp_fd_set(fd_set *rfds, int extra_fd)
|
|
{
|
|
FD_ZERO(rfds);
|
|
FD_SET(signal_pipe.rd, rfds);
|
|
if (extra_fd >= 0) {
|
|
close_on_exec_on(extra_fd);
|
|
FD_SET(extra_fd, rfds);
|
|
}
|
|
return signal_pipe.rd > extra_fd ? signal_pipe.rd : extra_fd;
|
|
}
|
|
|
|
/* Read a signal from the signal pipe. Returns 0 if there is
|
|
* no signal, -1 on error (and sets errno appropriately), and
|
|
* your signal on success */
|
|
int FAST_FUNC udhcp_sp_read(const fd_set *rfds)
|
|
{
|
|
unsigned char sig;
|
|
|
|
if (!FD_ISSET(signal_pipe.rd, rfds))
|
|
return 0;
|
|
|
|
if (safe_read(signal_pipe.rd, &sig, 1) != 1)
|
|
return -1;
|
|
|
|
return sig;
|
|
}
|