From 9e535b09a70a1ef7a2260e6d6955f7bbf291a08f Mon Sep 17 00:00:00 2001
From: Ron Yorston <rmy@pobox.com>
Date: Wed, 4 May 2022 14:26:39 +0100
Subject: win32: revert changes related to environment variables

Revert the change to mingw_putenv() in the previous commit.

When compiling for MSVCRT (i.e. not for UCRT) revert some of the
changes from commit 5b48ca53b (win32: pass NULL to spawnve, not
environ).

(GitHub issue #250)
---
 win32/env.c     | 20 ++++++++++++--------
 win32/process.c | 13 +++++++++----
 2 files changed, 21 insertions(+), 12 deletions(-)

diff --git a/win32/env.c b/win32/env.c
index 5de581e3d..4d4e9c8fd 100644
--- a/win32/env.c
+++ b/win32/env.c
@@ -78,7 +78,7 @@ int clearenv(void)
 
 int mingw_putenv(const char *env)
 {
-	char *s;
+	char *s, **envp;
 	int ret = 0;
 
 	if ( (s=strchr(env, '=')) == NULL ) {
@@ -90,13 +90,17 @@ int mingw_putenv(const char *env)
 		return _putenv(env);
 	}
 	else {
-		/* set empty value using WIN32 API*/
-		char *name = xstrdup(env);
-		name[s - env] = '\0';
-		SetEnvironmentVariable(name, "");
-		free(name);
-		/* set a dummy variable to force CRT housekeeping */
-		_putenv("BB_DUMMY=0");
+		/* set empty value by setting a non-empty one then truncating */
+		char *envstr = xasprintf("%s0", env);
+		ret = _putenv(envstr);
+
+		for (envp = environ; *envp; ++envp) {
+			if (strcmp(*envp, envstr) == 0) {
+				(*envp)[s - env + 1] = '\0';
+				break;
+			}
+		}
+		free(envstr);
 	}
 
 	return ret;
diff --git a/win32/process.c b/win32/process.c
index d4ab07ad8..5978226f0 100644
--- a/win32/process.c
+++ b/win32/process.c
@@ -345,27 +345,32 @@ mingw_spawnvp(int mode, const char *cmd, char *const *argv)
 {
 	char *prog;
 	intptr_t ret;
+#if !defined(_UCRT)
+	char *const *envp = environ;
+#else
+	char *const *envp = NULL;
+#endif
 
 #if ENABLE_FEATURE_PREFER_APPLETS && NUM_APPLETS > 1
 	if (find_applet_by_name(cmd) >= 0)
-		return mingw_spawn_applet(mode, argv, NULL);
+		return mingw_spawn_applet(mode, argv, envp);
 	else
 #endif
 	if (has_path(cmd)) {
 		char *path = alloc_system_drive(cmd);
 		add_win32_extension(path);
-		ret = mingw_spawn_interpreter(mode, path, argv, NULL, 0);
+		ret = mingw_spawn_interpreter(mode, path, argv, envp, 0);
 		free(path);
 #if ENABLE_FEATURE_PREFER_APPLETS && NUM_APPLETS > 1
 		if (ret == -1 && unix_path(cmd) &&
 				find_applet_by_name(bb_basename(cmd)) >= 0) {
-			return mingw_spawn_applet(mode, argv, NULL);
+			return mingw_spawn_applet(mode, argv, envp);
 		}
 #endif
 		return ret;
 	}
 	else if ((prog=find_first_executable(cmd)) != NULL) {
-		ret = mingw_spawn_interpreter(mode, prog, argv, NULL, 0);
+		ret = mingw_spawn_interpreter(mode, prog, argv, envp, 0);
 		free(prog);
 		return ret;
 	}
-- 
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