From a69ad46902e1efae0a21ac82a2d090149a17fd8c Mon Sep 17 00:00:00 2001
From: Thomas Bernard <miniupnp@free.fr>
Date: Tue, 15 Jan 2019 14:14:10 +0100
Subject: [PATCH] Get_current_directory() allocate buffer if needed

---
 src/io.c | 15 ++++++++++++++-
 src/io.h |  4 ++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/src/io.c b/src/io.c
index 2941b507..d4e1e81c 100644
--- a/src/io.c
+++ b/src/io.c
@@ -886,7 +886,18 @@ char * Get_current_directory(char * buf, word * buf_unicode, size_t size)
 
   return buf;
 #elif defined(WIN32)
-  /// @TODO allocate buf if needed
+  if (buf == NULL)
+  {
+    size = (size_t)GetCurrentDirectoryA(0, buf);
+    if (size == 0)
+      return NULL;
+    buf = malloc(size);
+    if (buf == NULL)
+    {
+      GFX2_Log(GFX2_ERROR, "Failed to allocate %lu bytes.\n", (unsigned long)size);
+      return NULL;
+    }
+  }
   if (GetCurrentDirectoryA(size, buf) == 0)
     return NULL;
   if (buf_unicode != NULL)
@@ -903,6 +914,8 @@ char * Get_current_directory(char * buf, word * buf_unicode, size_t size)
   return buf;
 #else
   char * ret = getcwd(buf, size);
+  if (ret == NULL)
+    GFX2_Log(GFX2_ERROR, "getcwd(%p, %lu) failed !\n", buf, (unsigned long)size);
 #ifdef ENABLE_FILENAMES_ICONV
   if (ret != NULL && buf_unicode != NULL)
   {
diff --git a/src/io.h b/src/io.h
index 1ef7085a..d1f900ef 100644
--- a/src/io.h
+++ b/src/io.h
@@ -183,6 +183,10 @@ void Release_lock_file(const char *file_directory);
 
 ///
 /// Return the current directory, equivalent to getcwd()
+/// @param buf destination buffer. can be NULL
+/// @param buf_unicode destination buffer for the unicode version of the path
+/// @param size destination buffer size, ignored if buf is NULL
+/// @return NULL for error, buf or a malloc'ed buffer
 char * Get_current_directory(char * buf, word * buf_unicode, size_t size);
 
 ///