librc: read RC_SCRIPTDIRS from the environment

Author: navi-desu

src/librc/librc.c

@@ -656,12 +656,30 @@ rc_set_user(void)
 	clear_dirfds();
 }
 
+static const char **env_scriptdirs;
+
 const char * const *
 rc_scriptdirs(void)
 {
+	static bool set = false;
+	const char *dirs;
+
 	if (rc_dirs.set)
 		return rc_dirs.scriptdirs;
-	return scriptdirs;
+
+	if (!set && (dirs = getenv("RC_SCRIPTDIRS"))) {
+		char *tmp = xstrdup(dirs);
+		unsigned entries = 0;
+
+		for (const char *entry = dirs; *entry; entry++)
+			entries += *entry == ':';
+		env_scriptdirs = calloc(entries + 2, sizeof(*scriptdirs));
+
+		for (size_t i = 0; i < entries + 1 && tmp; i++)
+			env_scriptdirs[i] = strsep(&tmp, ":");
+	}
+
+	return env_scriptdirs ? env_scriptdirs : scriptdirs;
 }
 
 size_t

src/shared/misc.c

@@ -59,6 +59,7 @@ static const char *const env_allowlist[] = {
 	"EERROR_QUIET", "EINFO_QUIET",
 	"IN_BACKGROUND", "IN_DRYRUN", "IN_HOTPLUG",
 	"RC_DEBUG", "RC_NODEPS", "RC_USER_SERVICES",
+	"RC_SCRIPTDIRS",
 	"LANG", "LC_MESSAGES", "TERM",
 	"EINFO_COLOR", "EINFO_VERBOSE",
 	NULL