Shut down curl operations before global cleanup.

Fixes KICAD-7DP
Fixes https://gitlab.com/kicad/code/kicad/-/issues/17103

common/kicad_curl/kicad_curl.cpp

@@ -3,7 +3,7 @@
  *
  * Copyright (C) 2015 Mark Roszko <mark.roszko@gmail.com>
  * Copyright (C) 2016 SoftPLC Corporation, Dick Hollenbeck <dick@softplc.com>
- * Copyright (C) 2015-2021 KiCad Developers, see AUTHORS.txt for contributors.
+ * Copyright (C) 2015-2024 KiCad Developers, see AUTHORS.txt for contributors.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -30,8 +30,14 @@
 #include <ki_exception.h>   // THROW_IO_ERROR
 
 
+static std::shared_mutex s_curlMutex;
+static bool              s_curlShuttingDown = false;
+
+
 void KICAD_CURL::Init()
 {
+    s_curlShuttingDown = false;
+
     if( curl_global_init( CURL_GLOBAL_ALL ) != CURLE_OK )
     {
         THROW_IO_ERROR( "curl_global_init() failed." );
@@ -41,10 +47,26 @@ void KICAD_CURL::Init()
 
 void KICAD_CURL::Cleanup()
 {
+    s_curlShuttingDown = true;
+
+    std::unique_lock lock( s_curlMutex );
+
     curl_global_cleanup();
 }
 
 
+std::shared_mutex& KICAD_CURL::Mutex()
+{
+    return s_curlMutex;
+}
+
+
+bool KICAD_CURL::IsShuttingDown()
+{
+    return s_curlShuttingDown;
+}
+
+
 std::string GetKicadCurlVersion()
 {
     return KICAD_CURL::GetVersion();

common/kicad_curl/kicad_curl_easy.cpp

@@ -2,7 +2,7 @@
  * This program source code file is part of KiCad, a free EDA CAD application.
  *
  * Copyright (C) 2015 Mark Roszko <mark.roszko@gmail.com>
- * Copyright (C) 2015-2023 KiCad Developers, see AUTHORS.txt for contributors.
+ * Copyright (C) 2015-2024 KiCad Developers, see AUTHORS.txt for contributors.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -33,6 +33,7 @@
 #include <cstddef>
 #include <exception>
 #include <sstream>
+#include <shared_mutex>
 #include <wx/app.h>
 
 #include <build_version.h>
@@ -88,6 +89,9 @@ static size_t stream_write_callback( void* aContents, size_t aSize, size_t aNmem
 static int xferinfo( void* aProgress, curl_off_t aDLtotal, curl_off_t aDLnow, curl_off_t aULtotal,
                      curl_off_t aULnow )
 {
+    if( KICAD_CURL::IsShuttingDown() )
+        return 1; // Should abort the operation
+
     CURL_PROGRESS* progress = static_cast<CURL_PROGRESS*>( aProgress );
     curl_off_t     curtime  = 0;
 
@@ -190,6 +194,12 @@ KICAD_CURL_EASY::~KICAD_CURL_EASY()
 
 int KICAD_CURL_EASY::Perform()
 {
+    std::shared_lock lock( KICAD_CURL::Mutex(), std::try_to_lock );
+
+    // If can't lock, we should be in the process of tearing down.
+    if( !lock )
+        return CURLE_ABORTED_BY_CALLBACK;
+
     if( m_headers )
         curl_easy_setopt( m_CURL, CURLOPT_HTTPHEADER, m_headers );
 

include/kicad_curl/kicad_curl.h

@@ -2,7 +2,7 @@
  * This program source code file is part of KiCad, a free EDA CAD application.
  *
  * Copyright (C) 2015 Mark Roszko <mark.roszko@gmail.com>
- * Copyright (C) 2015, 2021 KiCad Developers, see AUTHORS.txt for contributors.
+ * Copyright (C) 2015-2024 KiCad Developers, see AUTHORS.txt for contributors.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -44,6 +44,7 @@
 #include <kicommon.h>
 #include <curl/curl.h>
 #include <string>
+#include <shared_mutex>
 
 // CURL_EXTERN expands to dllimport on MinGW which causes gcc warnings.  This really should
 // expand to nothing on MinGW.
@@ -75,6 +76,17 @@ public:
      */
     static void Cleanup();
 
+    /**
+     * Returns the mutex for shared locking when performing curl operations.
+     * Unique locking is performed when shutting down.
+     */
+    static std::shared_mutex& Mutex();
+
+    /**
+     * Returns true if all curl operations should terminate.
+     */
+    static bool IsShuttingDown();
+
     /**
      * Wrapper for curl_version(). Reports back a short string of loaded libraries.
      *