[os2/process]: Fill in basic functions

core/os/os2/process_windows.odin

@@ -0,0 +1,46 @@
+//+build windows
+package os2
+
+import "core:sys/windows"
+
+_exit :: proc "contextless" (code: int) -> ! {
+	windows.ExitProcess(u32(code))
+}
+
+_get_uid :: proc() -> int {
+	return -1
+}
+
+_get_euid :: proc() -> int {
+	return -1
+}
+
+_get_gid :: proc() -> int {
+	return -1
+}
+
+_get_egid :: proc() -> int {
+	return -1
+}
+
+_get_pid :: proc() -> int {
+	return cast(int) windows.GetCurrentProcessId()
+}
+
+_get_ppid :: proc() -> int {
+	our_pid := windows.GetCurrentProcessId()
+	snap := windows.CreateToolhelp32Snapshot(windows.TH32CS_SNAPPROCESS, 0)
+	if snap == windows.INVALID_HANDLE_VALUE {
+		return -1
+	}
+	defer windows.CloseHandle(snap)
+	entry := windows.PROCESSENTRY32W { dwSize = size_of(windows.PROCESSENTRY32W) }
+	status := windows.Process32FirstW(snap, &entry)
+	for status {
+		if entry.th32ProcessID == our_pid {
+			return cast(int) entry.th32ParentProcessID
+		}
+		status = windows.Process32NextW(snap, &entry)
+	}
+	return -1
+}