From a15419f72cd02380d95fac2baa082a1235942077 Mon Sep 17 00:00:00 2001
From: Davin McCall <davmac@davmac.org>
Date: Mon, 12 Jun 2017 19:00:04 +0100
Subject: [PATCH] Fix potential issue of double-queueing for console breakage.

---
 src/service.cc | 16 ++++++++--------
 src/service.h  | 13 +++++++------
 2 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/src/service.cc b/src/service.cc
index b39fd10..d1d5160 100644
--- a/src/service.cc
+++ b/src/service.cc
@@ -72,7 +72,7 @@ void ServiceRecord::stopped() noexcept
     if (onstart_flags.runs_on_console) {
         tcsetpgrp(0, getpgrp());
         discard_console_log_buffer();
-        releaseConsole();
+        release_console();
     }
 
     force_stop = false;
@@ -628,7 +628,7 @@ void ServiceRecord::allDepsStarted(bool has_console) noexcept
 {
     if (onstart_flags.starts_on_console && ! has_console) {
         waiting_for_deps = true;
-        queueForConsole();
+        queue_for_console();
         return;
     }
     
@@ -648,14 +648,14 @@ void ServiceRecord::acquiredConsole() noexcept
 {
     if (service_state != ServiceState::STARTING) {
         // We got the console but no longer want it.
-        releaseConsole();
+        release_console();
     }
     else if (startCheckDependencies(false)) {
         allDepsStarted(true);
     }
     else {
         // We got the console but can't use it yet.
-        releaseConsole();
+        release_console();
     }
 }
 
@@ -692,7 +692,7 @@ void ServiceRecord::started() noexcept
 {
     if (onstart_flags.starts_on_console && ! onstart_flags.runs_on_console) {
         tcsetpgrp(0, getpgrp());
-        releaseConsole();
+        release_console();
     }
 
     logServiceStarted(service_name);
@@ -725,7 +725,7 @@ void ServiceRecord::failed_to_start(bool depfailed) noexcept
 {
     if (!depfailed && onstart_flags.starts_on_console) {
         tcsetpgrp(0, getpgrp());
-        releaseConsole();
+        release_console();
     }
     
     logServiceFailed(service_name);
@@ -1158,12 +1158,12 @@ void ServiceRecord::unpin() noexcept
     }
 }
 
-void ServiceRecord::queueForConsole() noexcept
+void ServiceRecord::queue_for_console() noexcept
 {
     service_set->append_console_queue(this);
 }
 
-void ServiceRecord::releaseConsole() noexcept
+void ServiceRecord::release_console() noexcept
 {
     service_set->pullConsoleQueue();
 }
diff --git a/src/service.h b/src/service.h
index 4ba8ab3..2a9774a 100644
--- a/src/service.h
+++ b/src/service.h
@@ -408,10 +408,11 @@ class ServiceRecord
     }
     
     // Queue to run on the console. 'acquiredConsole()' will be called when the console is available.
-    void queueForConsole() noexcept;
+    // Has no effect if the service has already queued for console.
+    void queue_for_console() noexcept;
     
     // Release console (console must be currently held by this service)
-    void releaseConsole() noexcept;
+    void release_console() noexcept;
     
     bool do_auto_restart() noexcept;
 
@@ -870,11 +871,11 @@ class ServiceSet
     }
     
     // Set the console queue tail (returns previous tail)
-    ServiceRecord * append_console_queue(ServiceRecord * newTail) noexcept
+    void append_console_queue(ServiceRecord * newTail) noexcept
     {
-        auto prev_tail = console_queue.tail();
-        console_queue.append(newTail);
-        return prev_tail;
+        if (! console_queue.is_queued(newTail)) {
+            console_queue.append(newTail);
+        }
     }
     
     // Retrieve the current console queue head and remove it from the queue
-- 
2.25.1