5420f32077
Andrii Nakryiko says: ==================== This patch set adds BTF-to-C dumping APIs to libbpf, allowing to output a subset of BTF types as a compilable C type definitions. This is useful by itself, as raw BTF output is not easy to inspect and comprehend. But it's also a big part of BPF CO-RE (compile once - run everywhere) initiative aimed at allowing to write relocatable BPF programs, that won't require on-the-host kernel headers (and would be able to inspect internal kernel structures, not exposed through kernel headers). This patch set consists of three groups of patches and one pre-patch, with the BTF-to-C dumper API depending on the first two groups. Pre-patch #1 fixes issue with libbpf_internal.h. btf__parse_elf() API patches: - patch #2 adds btf__parse_elf() API to libbpf, allowing to load BTF and/or BTF.ext from ELF file; - patch #3 utilizies btf__parse_elf() from bpftool for `btf dump file` command; - patch #4 switches test_btf.c to use btf__parse_elf() to check for presence of BTF data in object file. libbpf's internal hashmap patches: - patch #5 adds resizeable non-thread safe generic hashmap to libbpf; - patch #6 adds tests for that hashmap; - patch #7 migrates btf_dedup()'s dedup_table to use hashmap w/ APPEND. BTF-to-C dumper API patches: - patch #8 adds btf_dump APIs with all the logic for laying out type definitions in correct order and emitting C syntax for them; - patch #9 adds lots of tests for common and quirky parts of C type system; - patch #10 adds support for C-syntax btf dumping to bpftool; - patch #11 updates bpftool documentation to mention C-syntax dump option; - patch #12 update bash-completion for btf dump sub-command. v2->v3: - fix bpftool-btf.rst formatting (Quentin); - simplify bash autocompletion script (Quentin); - better error message in btf dump (Quentin); v1->v2: - removed unuseful file header (Jakub); - removed inlines in .c (Jakub); - added 'format {c|raw}' keyword/option (Jakub); - re-use i var for iteration in btf_dump_c() (Jakub); - bumped libbpf version to 0.0.4; v0->v1: - fix bug in hashmap__for_each_bucket_entry() not handling empty hashmap; - removed `btf dump`-specific libbpf logging hook up (Quentin has more generic patchset); - change btf__parse_elf() to always load .BTF and return it as a result, with .BTF.ext being optional and returned through struct btf_ext** arg (Alexei); - endianness check to use __BYTE_ORDER__ (Alexei); - bool:1 to __u8:1 in type_aux_state (Alexei); - added HASHMAP_APPEND strategy to hashmap, changed hashmap__for_each_key_entry() to also check for key equality during iteration (multimap iteration for key); - added new tests for empty hashmap and hashmap as a multimap; - tried to clarify weak/strong dependency ordering comments (Alexei) - btf dump test's expected output - support better commenting aproach (Alexei); - added bash-completion for a new "c" option (Alexei). ==================== Signed-off-by: Alexei Starovoitov <ast@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.