[PATCH] GetPrivateProfileString should set buffer to "" if default value is not set

[Christopher Smith]

Our existing tests for GetPrivateProfileString were not checking to see 
if strings were null terminated, and in particular, the case where 
lpDefault wasn't set, the code actually *didn't* set the target buffer 
to an empty string as it should. Valgrind noticed this problem, but the 
unit tests didn't, so I've updated the unit tests to add this test *and* 
fixed the relevant code to GetPrivateProfileString. Please find the 
patch attached.

--Chris

diff --git a/dlls/kernel32/profile.c b/dlls/kernel32/profile.c
index 9b6b1a1..e52cd66 100644
--- a/dlls/kernel32/profile.c
+++ b/dlls/kernel32/profile.c
@@ -1114,9 +1114,10 @@ static int PROFILE_GetPrivateProfileString( LPCWSTR section, LPCWSTR entry,
     } else if (buffer && def_val) {
        lstrcpynW( buffer, def_val, len );
        ret = strlenW( buffer );
-    }
-    else
+    } else {
+       buffer[0] = 0; /* buffer must be a null terminated empty string */
        ret = 0;
+    }

RtlLeaveCriticalSection( &PROFILE_CritSect );

diff --git a/dlls/kernel32/tests/profile.c b/dlls/kernel32/tests/profile.c
index cddc9a0..2f0ff13 100644
--- a/dlls/kernel32/tests/profile.c
+++ b/dlls/kernel32/tests/profile.c
@@ -338,11 +338,17 @@ static void test_profile_existing(void)
                        OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
         ok(INVALID_HANDLE_VALUE != h, "%d: CreateFile failed\n",i);
         SetLastError(0xdeadbeef);
+        /* Fill the buffer with non-zero values so we can test if the
+           result is properly null terminated */
+        memset(buffer, 0xff, sizeof(buffer));
         ret = GetPrivateProfileStringA(SECTION, KEY, NULL, buffer, MAX_PATH, testfile2);
         if (!pe[i].read_error)
             ok( ret, "%d: GetPrivateProfileString failed with error %u\n", i, GetLastError() );
         else
+        {
             ok( !ret, "%d: GetPrivateProfileString succeeded\n", i );
+            ok( buffer[ret] == 0, "Get GetPrivateProfileString should terminate buffer with null\n" );
+        }
         CloseHandle(h);
     }
     ok( DeleteFile(testfile2), "delete failed\n" );