From a0f6932ebe21ff6908db250019bdb46f7b0dfedc Mon Sep 17 00:00:00 2001
From: Max Kellermann <max.kellermann@gmail.com>
Date: Mon, 6 Mar 2023 12:53:19 +0100
Subject: [PATCH] unix/SignalHandlers: shut down if parent process dies in
--no-daemon mode
By default, if the parent of a process dies, the process gets SIGHUP
and is supposed to shut down. This however doesn't work for MPD,
because MPD redefines SIGHUP with a different meaning (like most
daemons do).
To work around this, we configure the kernel to send SIGTERM instead
of SIGHUP.
Closes https://github.com/MusicPlayerDaemon/MPD/issues/1706
---
NEWS | 2 ++
src/Main.cxx | 5 ++++-
src/unix/SignalHandlers.cxx | 14 +++++++++++++-
src/unix/SignalHandlers.hxx | 6 +++---
4 files changed, 22 insertions(+), 5 deletions(-)
diff --git a/NEWS b/NEWS
index 23e59ede8..5cb84ea24 100644
--- a/NEWS
+++ b/NEWS
@@ -3,6 +3,8 @@ ver 0.23.13 (not yet released)
- curl: fix busy loop after connection failed
* output
- pipewire: fix corruption bug due to missing lock
+* Linux
+ - shut down if parent process dies in --no-daemon mode
ver 0.23.12 (2023/01/17)
* input
diff --git a/src/Main.cxx b/src/Main.cxx
index bcbda0bb5..6b9bdf641 100644
--- a/src/Main.cxx
+++ b/src/Main.cxx
@@ -482,7 +482,10 @@ MainConfigured(const CommandLineOptions &options,
#ifndef ANDROID
setup_log_output();
- const ScopeSignalHandlersInit signal_handlers_init(instance);
+ const ScopeSignalHandlersInit signal_handlers_init{
+ instance,
+ options.daemon,
+ };
#endif
instance.io_thread.Start();
diff --git a/src/unix/SignalHandlers.cxx b/src/unix/SignalHandlers.cxx
index 886dc78d5..e58dda7de 100644
--- a/src/unix/SignalHandlers.cxx
+++ b/src/unix/SignalHandlers.cxx
@@ -30,6 +30,10 @@
#include <csignal>
+#ifdef __linux__
+#include <sys/prctl.h>
+#endif
+
static constexpr Domain signal_handlers_domain("signal_handlers");
static void
@@ -60,7 +64,7 @@ handle_reload_event(void *ctx) noexcept
#endif
void
-SignalHandlersInit(Instance &instance)
+SignalHandlersInit(Instance &instance, bool daemon)
{
auto &loop = instance.event_loop;
@@ -79,6 +83,14 @@ SignalHandlersInit(Instance &instance)
SignalMonitorRegister(SIGHUP, {&instance, handle_reload_event});
#endif
+
+ if (!daemon) {
+#ifdef __linux__
+ /* if MPD was not daemonized, shut it down when the
+ parent process dies */
+ prctl(PR_SET_PDEATHSIG, SIGTERM);
+#endif
+ }
}
void
diff --git a/src/unix/SignalHandlers.hxx b/src/unix/SignalHandlers.hxx
index dbcec12d6..1eb9a305d 100644
--- a/src/unix/SignalHandlers.hxx
+++ b/src/unix/SignalHandlers.hxx
@@ -23,15 +23,15 @@
struct Instance;
void
-SignalHandlersInit(Instance &instance);
+SignalHandlersInit(Instance &instance, bool daemon);
void
SignalHandlersFinish() noexcept;
class ScopeSignalHandlersInit {
public:
- ScopeSignalHandlersInit(Instance &instance) {
- SignalHandlersInit(instance);
+ ScopeSignalHandlersInit(Instance &instance, bool daemon) {
+ SignalHandlersInit(instance, daemon);
}
~ScopeSignalHandlersInit() noexcept {