Rémi Bernon : msvcrt: Fix _dupenv_s behavior with missing env var.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 5a08eab3033edf1f858776523699f333d793a8c1
URL:    https://gitlab.winehq.org/wine/wine/-/commit/5a08eab3033edf1f858776523699f33...

Author: Rémi Bernon 
Date:   Thu Feb 23 12:20:30 2023 +0100

msvcrt: Fix _dupenv_s behavior with missing env var.

---

dlls/msvcr80/tests/msvcr80.c | 3 ---
 dlls/msvcrt/environ.c        | 7 ++++++-
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/dlls/msvcr80/tests/msvcr80.c b/dlls/msvcr80/tests/msvcr80.c
index 34f50cd6a69..961bef504b6 100644
--- a/dlls/msvcr80/tests/msvcr80.c
+++ b/dlls/msvcr80/tests/msvcr80.c
@@ -197,11 +197,8 @@ static void test_dupenv_s(void)
     len = 0xdeadbeef;
     tmp = (void *)0xdeadbeef;
     ret = p_dupenv_s( &tmp, &len, "nonexistent" );
-    todo_wine
     ok( !ret, "_dupenv_s returned %d\n", ret );
-    todo_wine
     ok( !len, "_dupenv_s returned length is %Id\n", len );
-    todo_wine
     ok( !tmp, "_dupenv_s returned pointer is %p\n", tmp );
 }

diff --git a/dlls/msvcrt/environ.c b/dlls/msvcrt/environ.c
index 729eb0560bd..e9c15b732ba 100644
--- a/dlls/msvcrt/environ.c
+++ b/dlls/msvcrt/environ.c
@@ -249,7 +249,12 @@ int CDECL _dupenv_s(char **buffer, size_t *numberOfElements, const char *varname
     if (!MSVCRT_CHECK_PMT(buffer != NULL)) return EINVAL;
     if (!MSVCRT_CHECK_PMT(varname != NULL)) return EINVAL;

-    if (!(e = getenv(varname))) return *_errno() = EINVAL;
+    if (!(e = getenv(varname)))
+    {
+        *buffer = NULL;
+        if (numberOfElements) *numberOfElements = 0;
+        return 0;
+    }

sz = strlen(e) + 1;
     if (!(*buffer = malloc(sz)))