From a1c83fc7655180f6e779096bc42a80dc6eed05aa Mon Sep 17 00:00:00 2001
From: Devaev Maxim <mdevaev@gmail.com>
Date: Tue, 8 Oct 2019 23:32:23 +0300
Subject: [PATCH] --exit-on-parent-death

---
 src/options.c | 18 ++++++++++++++++
 src/process.h | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 78 insertions(+)
 create mode 100644 src/process.h

diff --git a/src/options.c b/src/options.c
index 1edeae4..192a776 100644
--- a/src/options.c
+++ b/src/options.c
@@ -36,6 +36,7 @@
 
 #include "config.h"
 #include "logging.h"
+#include "process.h"
 #include "device.h"
 #include "encoder.h"
 #include "http/server.h"
@@ -107,6 +108,10 @@ enum _OPT_VALUES {
 	_O_GPIO_WORKERS_BUSY_AT,
 #endif
 
+#ifdef HAS_PROCESS_SET_SIGTERM_ON_PARENT_DEATH
+	_O_EXIT_ON_PARENT_DEATH,
+#endif
+
 	_O_LOG_LEVEL,
 	_O_PERF,
 	_O_VERBOSE,
@@ -171,6 +176,10 @@ static const struct option _LONG_OPTS[] = {
 	{"gpio-workers-busy-at",	required_argument,	NULL,	_O_GPIO_WORKERS_BUSY_AT},
 #endif
 
+#ifdef HAS_PROCESS_SET_SIGTERM_ON_PARENT_DEATH
+	{"exit-on-parent-death",	no_argument,		NULL,	_O_EXIT_ON_PARENT_DEATH},
+#endif
+
 	{"log-level",				required_argument,	NULL,	_O_LOG_LEVEL},
 	{"perf",					no_argument,		NULL,	_O_PERF},
 	{"verbose",					no_argument,		NULL,	_O_VERBOSE},
@@ -333,6 +342,10 @@ int parse_options(int argc, char *argv[], struct device_t *dev, struct encoder_t
 			case _O_GPIO_WORKERS_BUSY_AT:	OPT_NUMBER("--gpio-workers-busy-at", gpio_pin_workers_busy_at, 0, 256, 0);
 #			endif
 
+#			ifdef HAS_PROCESS_SET_SIGTERM_ON_PARENT_DEATH
+			case _O_EXIT_ON_PARENT_DEATH:	process_set_sigterm_on_parent_death(); break;
+#			endif
+
 			case _O_LOG_LEVEL:			OPT_NUMBER("--log-level", log_level, LOG_LEVEL_INFO, LOG_LEVEL_DEBUG, 0);
 			case _O_PERF:				OPT_SET(log_level, LOG_LEVEL_PERF);
 			case _O_VERBOSE:			OPT_SET(log_level, LOG_LEVEL_VERBOSE);
@@ -538,6 +551,11 @@ static void _help(struct device_t *dev, struct encoder_t *encoder, struct http_s
 	printf("    --gpio-has-http-clients <pin>  ─ Set 1 while stream has at least one client. Default: disabled.\n\n");
 	printf("    --gpio-workers-busy-at <pin>  ── Set 1 on (pin + N) while worker with number N has a job.\n");
 	printf("                                     The worker's numbering starts from 0. Default: disabled\n\n");
+#endif
+#ifdef HAS_PROCESS_SET_SIGTERM_ON_PARENT_DEATH
+	printf("Process options:\n");
+	printf("════════════════\n");
+	printf("    --exit-on-parent-death  ─ Exit the program if the parent process is dead. Default: disabled.\n\n");
 #endif
 	printf("Logging options:\n");
 	printf("════════════════\n");
diff --git a/src/process.h b/src/process.h
new file mode 100644
index 0000000..f4550ea
--- /dev/null
+++ b/src/process.h
@@ -0,0 +1,60 @@
+/*****************************************************************************
+#                                                                            #
+#    uStreamer - Lightweight and fast MJPG-HTTP streamer.                    #
+#                                                                            #
+#    Copyright (C) 2018  Maxim Devaev <mdevaev@gmail.com>                    #
+#                                                                            #
+#    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 3 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, see <https://www.gnu.org/licenses/>.  #
+#                                                                            #
+*****************************************************************************/
+
+
+#pragma once
+
+#if defined(__linux__)
+#	define HAS_PROCESS_SET_SIGTERM_ON_PARENT_DEATH
+#elif defined(__FreeBSD__)
+#	include <sys/param.h>
+#	if __FreeBSD_version >= 1102000
+#		define HAS_PROCESS_SET_SIGTERM_ON_PARENT_DEATH
+#	endif
+#endif
+
+#ifdef HAS_PROCESS_SET_SIGTERM_ON_PARENT_DEATH
+#	include <signal.h>
+
+#	if defined(__linux__)
+#		include <sys/prctl.h>
+#	elif defined(__FreeBSD__)
+#		include <sys/procctl.h>
+#	endif
+
+#	include "logging.h"
+
+
+INLINE void process_set_sigterm_on_parent_death(void) {
+	int signum = SIGTERM;
+#	ifdef __linux__
+	int retval = prctl(PR_SET_PDEATHSIG, signum);
+#	elif __FreeBSD__
+	int retval = procctl(P_PID, 0, PROC_PDEATHSIG_CTL, &signum);
+#	else
+#		error WTF?
+#	endif
+	if (retval < 0) {
+		LOG_PERROR("Can't set to receive SIGTERM on parent process death");
+	}
+}
+
+#endif