Audit Interface Limitations

There are some limitations regarding the use of the la_pltexit() and ld_pltexit64() functions. These limitations stem from the need to insert an extra stack frame between the caller and callee to provide a means of acquiring the la_pltexit() return value. This is not a problem when calling just the la_*_pltenter() routines, as any intervening stack can be cleaned up prior to transferring control to the destination function.

Because of these limitations, la_pltexit() and la_pltexit64() should be considered experimental interfaces, that might change in future releases to better address these limitations. When in doubt, the use of la_pltexit() should be avoided.

Functions That Directly Inspect the Stack

A small number of functions exist that directly inspect the stack or make assumptions regarding its state. Some examples of these functions are the setjmp(3C) family, vfork(2), and any function that returns a structure (not a pointer to a structure). These functions will be compromised by the extra stack created to support la_pltexit().

The runtime linker cannot detect functions of this type, and thus it becomes the responsibility of the audit library creator to disable la_pltexit() for such routines.