[PATCH] ntdll: Check for debug output buffer overflow in __wine_dbg_output().

[Józef Kucia]

This makes __wine_dbg_output() slightly more robust. The change prevents the
debug output buffer overflow when __wine_dbg_output() is called repeatedly
with small strings.

Signed-off-by: Józef Kucia <jkucia at codeweavers.com>
---

Supersedes patch 164513.

---
 dlls/ntdll/debugtools.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/dlls/ntdll/debugtools.c b/dlls/ntdll/debugtools.c
index 64355ab3b841..027ca0236051 100644
--- a/dlls/ntdll/debugtools.c
+++ b/dlls/ntdll/debugtools.c
@@ -235,6 +235,7 @@ int __cdecl __wine_dbg_output( const char *str )
     struct debug_info *info = get_info();
     const char *end = strrchr( str, '\n' );
     int ret = 0;
+    size_t n;
 
     if (end)
     {
@@ -243,7 +244,16 @@ int __cdecl __wine_dbg_output( const char *str )
         info->out_pos = 0;
         str = end + 1;
     }
-    if (*str) ret += append_output( info, str, strlen( str ));
+    if (*str)
+    {
+        n = strlen( str );
+        if (n >= sizeof(info->output) - info->out_pos && info->out_pos)
+        {
+            write( 2, info->output, info->out_pos );
+            info->out_pos = 0;
+        }
+        ret += append_output( info, str, n );
+    }
     return ret;
 }
 
-- 
2.21.0