From 8fd2746696d32262b2e6900879a9a315e56f76f2 Mon Sep 17 00:00:00 2001
From: Florent Le Coz <louiz@louiz.org>
Date: Wed, 19 Feb 2014 02:24:00 +0100
Subject: Reload the conf on SIGUSR1/2

---
 doc/biboumi.1.md      |  4 ++++
 src/config/config.cpp |  1 -
 src/main.cpp          | 39 ++++++++++++++++++++++++++++++++-------
 3 files changed, 36 insertions(+), 8 deletions(-)

diff --git a/doc/biboumi.1.md b/doc/biboumi.1.md
index 334e65e..18482fb 100644
--- a/doc/biboumi.1.md
+++ b/doc/biboumi.1.md
@@ -57,6 +57,10 @@ The configuration file uses a simple format of the form
   from 0 to 3.  0 is debug, 1 is info, 2 is warning, 3 is error.  The
   default is 0, but a more practical value for production use is 1.
 
+The configuration can be re-read at runtime (you can for example change the
+log level without having to restart biboumi) by sending SIGUSR1 or SIGUSR2
+(see kill(1)) to the process.
+
 USAGE
 -----
 
diff --git a/src/config/config.cpp b/src/config/config.cpp
index 5f937e6..82295d5 100644
--- a/src/config/config.cpp
+++ b/src/config/config.cpp
@@ -56,7 +56,6 @@ void Config::connect(t_config_changed_callback callback)
 void Config::close()
 {
   Config* self = Config::instance().get();
-  self->save_to_file();
   self->values.clear();
   Config::instance().reset();
 }
diff --git a/src/main.cpp b/src/main.cpp
index 28f5a76..b27fd8b 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -10,7 +10,9 @@
 #include <signal.h>
 
 // A flag set by the SIGINT signal handler.
-volatile std::atomic<bool> stop(false);
+static volatile std::atomic<bool> stop(false);
+// Flag set by the SIGUSR1/2 signal handler.
+static volatile std::atomic<bool> reload(false);
 // A flag indicating that we are wanting to exit the process. i.e: if this
 // flag is set and all connections are closed, we can exit properly.
 static bool exiting = false;
@@ -35,6 +37,11 @@ static void sigint_handler(int, siginfo_t*, void*)
   stop = true;
 }
 
+static void sigusr_handler(int, siginfo_t*, void*)
+{
+  reload = true;
+}
+
 int main(int ac, char** av)
 {
   if (ac > 1)
@@ -69,14 +76,21 @@ int main(int ac, char** av)
   // config
   sigset_t mask;
   sigemptyset(&mask);
-  struct sigaction on_sig;
-  on_sig.sa_sigaction = &sigint_handler;
-  on_sig.sa_mask = mask;
+  struct sigaction on_sigint;
+  on_sigint.sa_sigaction = &sigint_handler;
+  on_sigint.sa_mask = mask;
   // we want to catch that signal only once.
   // Sending SIGINT again will "force" an exit
-  on_sig.sa_flags = SA_RESETHAND;
-  sigaction(SIGINT, &on_sig, nullptr);
-  sigaction(SIGTERM, &on_sig, nullptr);
+  on_sigint.sa_flags = SA_RESETHAND;
+  sigaction(SIGINT, &on_sigint, nullptr);
+  sigaction(SIGTERM, &on_sigint, nullptr);
+
+  // Install a signal to reload the config on SIGUSR1/2
+  struct sigaction on_sigusr;
+  on_sigusr.sa_sigaction = &sigusr_handler;
+  on_sigusr.sa_mask = mask;
+  sigaction(SIGUSR1, &on_sigusr, nullptr);
+  sigaction(SIGUSR2, &on_sigusr, nullptr);
 
   const std::chrono::milliseconds timeout(-1);
   while (p.poll(timeout) != -1 || !exiting)
@@ -91,6 +105,17 @@ int main(int ac, char** av)
       stop = false;
       xmpp_component->shutdown();
     }
+    if (reload)
+    {
+      // Closing the config will just force it to be reopened the next time
+      // a configuration option is needed
+      log_info("Signal received, reloading the config...");
+      Config::close();
+      // Destroy the logger instance, to be recreated the next time a log
+      // line needs to be written
+      Logger::instance().reset();
+      reload = false;
+    }
     // If the only existing connection is the one to the XMPP component:
     // close the XMPP stream.
     if (exiting && p.size() == 1 && xmpp_component->is_document_open())
-- 
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