737d0646a8
Add high-level API wrappers for most common and typical BPF map operations that works directly on instances of struct bpf_map * (so you don't have to call bpf_map__fd()) and validate key/value size expectations. These helpers require users to specify key (and value, where appropriate) sizes when performing lookup/update/delete/etc. This forces user to actually think and validate (for themselves) those. This is a good thing as user is expected by kernel to implicitly provide correct key/value buffer sizes and kernel will just read/write necessary amount of data. If it so happens that user doesn't set up buffers correctly (which bit people for per-CPU maps especially) kernel either randomly overwrites stack data or return -EFAULT, depending on user's luck and circumstances. These high-level APIs are meant to prevent such unpleasant and hard to debug bugs. This patch also adds bpf_map_delete_elem_flags() low-level API and requires passing flags to bpf_map__delete_elem() API for consistency across all similar APIs, even though currently kernel doesn't expect any extra flags for BPF_MAP_DELETE_ELEM operation. List of map operations that get these high-level APIs: - bpf_map_lookup_elem; - bpf_map_update_elem; - bpf_map_delete_elem; - bpf_map_lookup_and_delete_elem; - bpf_map_get_next_key. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20220512220713.2617964-1-andrii@kernel.org
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.