OS: Add `unset_environment`, better validate input

Instead of returning an undocumented boolean error code, we do the
validation checks that should ensure a successful result.

Based on:
- https://linux.die.net/man/3/setenv
- https://learn.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-setenvironmentvariable

2 files changed, 16 insertions, 7 deletions

diff --git a/drivers/unix/os_unix.cpp b/drivers/unix/os_unix.cpp
index c37b3d9c87..178f01b185 100644
--- a/drivers/unix/os_unix.cpp
+++ b/drivers/unix/os_unix.cpp
@@ -411,10 +411,6 @@ bool OS_Unix::is_process_running(const ProcessID &p_pid) const {
 	return true;
 }
 
-bool OS_Unix::has_environment(const String &p_var) const {
-	return getenv(p_var.utf8().get_data()) != nullptr;
-}
-
 String OS_Unix::get_locale() const {
 	if (!has_environment("LANG")) {
 		return "en";
@@ -487,6 +483,10 @@ Error OS_Unix::set_cwd(const String &p_cwd) {
 	return OK;
 }
 
+bool OS_Unix::has_environment(const String &p_var) const {
+	return getenv(p_var.utf8().get_data()) != nullptr;
+}
+
 String OS_Unix::get_environment(const String &p_var) const {
 	if (getenv(p_var.utf8().get_data())) {
 		return getenv(p_var.utf8().get_data());
@@ -494,8 +494,15 @@ String OS_Unix::get_environment(const String &p_var) const {
 	return "";
 }
 
-bool OS_Unix::set_environment(const String &p_var, const String &p_value) const {
-	return setenv(p_var.utf8().get_data(), p_value.utf8().get_data(), /* overwrite: */ true) == 0;
+void OS_Unix::set_environment(const String &p_var, const String &p_value) const {
+	ERR_FAIL_COND_MSG(p_var.is_empty() || p_var.contains("="), vformat("Invalid environment variable name '%s', cannot be empty or include '='.", p_var));
+	int err = setenv(p_var.utf8().get_data(), p_value.utf8().get_data(), /* overwrite: */ 1);
+	ERR_FAIL_COND_MSG(err != 0, vformat("Failed setting environment variable '%s', the system is out of memory.", p_var));
+}
+
+void OS_Unix::unset_environment(const String &p_var) const {
+	ERR_FAIL_COND_MSG(p_var.is_empty() || p_var.contains("="), vformat("Invalid environment variable name '%s', cannot be empty or include '='.", p_var));
+	unsetenv(p_var.utf8().get_data());
 }
 
 String OS_Unix::get_user_data_dir() const {
diff --git a/drivers/unix/os_unix.h b/drivers/unix/os_unix.h
index 416311307c..03429622ae 100644
--- a/drivers/unix/os_unix.h
+++ b/drivers/unix/os_unix.h
@@ -81,7 +81,9 @@ public:
 
 	virtual bool has_environment(const String &p_var) const override;
 	virtual String get_environment(const String &p_var) const override;
-	virtual bool set_environment(const String &p_var, const String &p_value) const override;
+	virtual void set_environment(const String &p_var, const String &p_value) const override;
+	virtual void unset_environment(const String &p_var) const override;
+
 	virtual String get_locale() const override;
 
 	virtual void initialize_debugging() override;