From f51e50a4237831b6bdac49c1704bbb02b34dacd9 Mon Sep 17 00:00:00 2001
From: LazyBumHorse <CirilCatington@gmail.com>
Date: Thu, 15 Aug 2019 13:39:19 +0200
Subject: [PATCH] fix logging on Windows sometimes not being null-terminated

---
 gfx/drivers_context/wgl_ctx.c | 12 +++++++-----
 verbosity.c                   | 20 +++++++++++++++++++-
 2 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/gfx/drivers_context/wgl_ctx.c b/gfx/drivers_context/wgl_ctx.c
index ac2c09a0d5..583b4d104d 100644
--- a/gfx/drivers_context/wgl_ctx.c
+++ b/gfx/drivers_context/wgl_ctx.c
@@ -357,12 +357,14 @@ static void create_gl_context(HWND hwnd, bool *quit)
       wglGetExtensionsStringARB = (const char *(WINAPI *) (HDC))
          gfx_ctx_wgl_get_proc_address("wglGetExtensionsStringARB");
       if (wglGetExtensionsStringARB)
-         extensions = wglGetExtensionsStringARB(win32_hdc);
-      RARCH_LOG("[WGL] extensions: %s\n", extensions);
-      if (wgl_has_extension("WGL_EXT_swap_control_tear", extensions))
       {
-         RARCH_LOG("[WGL]: Adaptive VSync supported.\n");
-         wgl_adaptive_vsync = true;
+         extensions = wglGetExtensionsStringARB(win32_hdc);
+         RARCH_LOG("[WGL] extensions: %s\n", extensions);
+         if (wgl_has_extension("WGL_EXT_swap_control_tear", extensions))
+         {
+            RARCH_LOG("[WGL]: Adaptive VSync supported.\n");
+            wgl_adaptive_vsync = true;
+         }
       }
    }
 }
diff --git a/verbosity.c b/verbosity.c
index 31ba3db947..9d362acd66 100644
--- a/verbosity.c
+++ b/verbosity.c
@@ -218,9 +218,27 @@ void RARCH_LOG_V(const char *tag, const char *fmt, va_list ap)
 #else
    FILE *fp = (FILE*)log_file_fp;
 #if defined(HAVE_QT) || defined(__WINRT__)
+   int ret;
    char buffer[256];
    buffer[0] = '\0';
-   vsnprintf(buffer, sizeof(buffer), fmt, ap);
+   ret = vsnprintf(buffer, sizeof(buffer), fmt, ap);
+
+   /* ensure null termination and line break in error case */
+   if (ret < 0)
+   {
+      int end;
+      buffer[sizeof buffer - 1]  = '\0';
+      end = strlen(buffer) - 1;
+      if (end >= 0)
+      {
+         buffer[end] = '\n';
+      }
+      else
+      {
+         buffer[0] = '\n';
+         buffer[1] = '\0';
+      }
+   }
 
    if (fp)
    {