Module auxv::stack

Read auxv entries by chasing pointers in the ELF stack layout.

The sole public function is iterate_stack_auxv. It iterates across the entries, exposing them via AuxvPair. The two fields in AuxvPair will be of type AuxvType.

Only use this code when all of the following are satisfied:

• In an ELF binary. In practice, this means Linux, FreeBSD, and other Unix variants (but not macOS).
• No other threads have manipulating the environment (setenv, putenv, or equivalent). In practice this means do it as the very first stuff in main before touching the environment or spawning any other threads.

This works by navigating the stack at runtime to find the auxv entries, so it is unsafe. It may segfault or produce bogus output when run on non-ELF systems or when the environment has been modified. It relies on navigating from the original destination of the environ pointer in the ELF stack layout to auxv.

iterate_stack_auxv is not available on Windows since they use a different (non-POSIX) environment pointer name. And, of course, it wouldn't work even if it compiled.

If you're on a system with ELF executables (Linux, FreeBSD, other Unixes), run the example that shows its own auxv keys and values: cargo run --example elf_stack_show_auxv. It should print a short table of a dozen or two numbers. On macOS, it tends to produce garbage numbers for a while before mercifully exiting normally. On Windows, the function is not available because their names are not POSIX compatible so it wouldn't even compile, and so the example prints nothing.

Structs

StackAuxvIter

An iterator across auxv pairs from crawling the ELF stack.