From 3de2f13b89ce1f6671488c4b6c0b23f4b825531b Mon Sep 17 00:00:00 2001
From: Simon Tatham <anakin@pobox.com>
Date: Sat, 24 Apr 2021 17:15:47 +0100
Subject: [PATCH] Factor out Windows utility function get_system_dir().

The code to find out the location of the c:\windows\system32 directory
was already present, in load_system32_dll(). Now it's moved out into a
function of its own, so it can be called in other contexts.
---
 windows/CMakeLists.txt            |  1 +
 windows/platform.h                |  1 +
 windows/utils/get_system_dir.c    | 21 +++++++++++++++++++++
 windows/utils/load_system32_dll.c | 10 +---------
 4 files changed, 24 insertions(+), 9 deletions(-)
 create mode 100644 windows/utils/get_system_dir.c

diff --git a/windows/CMakeLists.txt b/windows/CMakeLists.txt
index 288827cb..fb2b3028 100644
--- a/windows/CMakeLists.txt
+++ b/windows/CMakeLists.txt
@@ -10,6 +10,7 @@ add_sources_from_current_dir(utils
   utils/filename.c
   utils/fontspec.c
   utils/getdlgitemtext_alloc.c
+  utils/get_system_dir.c
   utils/get_username.c
   utils/is_console_handle.c
   utils/load_system32_dll.c
diff --git a/windows/platform.h b/windows/platform.h
index f84f4236..5c307cb0 100644
--- a/windows/platform.h
+++ b/windows/platform.h
@@ -566,6 +566,7 @@ HWND event_log_window(void);
 extern DWORD osMajorVersion, osMinorVersion, osPlatformId;
 void init_winver(void);
 void dll_hijacking_protection(void);
+const char *get_system_dir(void);
 HMODULE load_system32_dll(const char *libname);
 const char *win_strerror(int error);
 void restrict_process_acl(void);
diff --git a/windows/utils/get_system_dir.c b/windows/utils/get_system_dir.c
new file mode 100644
index 00000000..049cd7fc
--- /dev/null
+++ b/windows/utils/get_system_dir.c
@@ -0,0 +1,21 @@
+/*
+ * Wrapper function around GetSystemDirectory that deals with
+ * allocating the output buffer, and also caches the result for future
+ * calls.
+ */
+
+#include "putty.h"
+
+const char *get_system_dir(void)
+{
+    static char *sysdir = NULL;
+    static size_t sysdirsize = 0;
+
+    if (!sysdir) {
+        size_t len;
+        while ((len = GetSystemDirectory(sysdir, sysdirsize)) >= sysdirsize)
+            sgrowarray(sysdir, sysdirsize, len);
+    }
+
+    return sysdir;
+}
diff --git a/windows/utils/load_system32_dll.c b/windows/utils/load_system32_dll.c
index e00d7c34..d227a264 100644
--- a/windows/utils/load_system32_dll.c
+++ b/windows/utils/load_system32_dll.c
@@ -8,18 +8,10 @@
 
 HMODULE load_system32_dll(const char *libname)
 {
-    static char *sysdir = NULL;
-    static size_t sysdirsize = 0;
     char *fullpath;
     HMODULE ret;
 
-    if (!sysdir) {
-        size_t len;
-        while ((len = GetSystemDirectory(sysdir, sysdirsize)) >= sysdirsize)
-            sgrowarray(sysdir, sysdirsize, len);
-    }
-
-    fullpath = dupcat(sysdir, "\\", libname);
+    fullpath = dupcat(get_system_dir(), "\\", libname);
     ret = LoadLibrary(fullpath);
     sfree(fullpath);
     return ret;