os/os2: add get_executable_path and get_executable_directory

core/os/os2/path_freebsd.odin

@@ -0,0 +1,29 @@
+package os2
+
+import "base:runtime"
+
+import "core:sys/freebsd"
+import "core:sys/posix"
+
+_get_executable_path :: proc(allocator: runtime.Allocator) -> (path: string, err: Error) {
+	req := []freebsd.MIB_Identifier{.CTL_KERN, .KERN_PROC, .KERN_PROC_PATHNAME, freebsd.MIB_Identifier(-1)}
+
+	size: uint
+	if ret := freebsd.sysctl(req, nil, &size, nil, 0); ret != .NONE {
+		err = _get_platform_error(posix.Errno(ret))
+		return
+	}
+	assert(size > 0)
+
+	buf := make([]byte, size, allocator) or_return
+	defer if err != nil { delete(buf, allocator) }
+
+	assert(uint(len(buf)) == size)
+
+	if ret := freebsd.sysctl(req, raw_data(buf), &size, nil, 0); ret != .NONE {
+		err = _get_platform_error(posix.Errno(ret))
+		return
+	}
+
+	return string(buf[:size]), nil
+}