docs: reconfigure libbpf documentation syncing

This adds documentation files, including ones for autogenerating API
documentation based on code comments in the source code that's pulled
in via the mirror.

Signed-off-by: Grant Seltzer <grantseltzer@gmail.com>

.readthedocs.yaml

@@ -0,0 +1,17 @@
+# .readthedocs.yaml
+# Read the Docs configuration file
+# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
+
+# Required
+version: 2
+
+# Build documentation in the docs/ directory with Sphinx
+sphinx:
+  builder: html
+  configuration: docs/conf.py
+
+# Optionally set the version of Python and requirements required to build your docs
+python:
+   version: 3.7
+   install:
+   - requirements: docs/sphinx/requirements.txt

docs/.gitignore

@@ -0,0 +1,2 @@
+sphinx/build
+sphinx/doxygen/build

docs/api.rst

@@ -0,0 +1,51 @@
+.. SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+
+.. _api:
+
+.. toctree:: Table of Contents
+   
+
+LIBBPF API
+==================
+
+libbpf.h
+--------
+.. doxygenfile:: libbpf.h
+   :project: libbpf
+   :sections: func define public-type
+
+bpf.h
+-----
+.. doxygenfile:: bpf.h
+   :project: libbpf
+   :sections: func define public-type
+
+btf.h
+-----
+.. doxygenfile:: btf.h
+   :project: libbpf
+   :sections: func define public-type
+
+xsk.h
+-----
+.. doxygenfile:: xsk.h
+   :project: libbpf
+   :sections: func define public-type
+
+bpf_tracing.h
+-------------
+.. doxygenfile:: bpf_tracing.h
+   :project: libbpf
+   :sections: func define public-type
+
+bpf_core_read.h
+---------------
+.. doxygenfile:: bpf_core_read.h
+   :project: libbpf
+   :sections: func define public-type
+
+bpf_endian.h
+------------
+.. doxygenfile:: bpf_endian.h
+   :project: libbpf
+   :sections: func define public-type

docs/conf.py

@@ -0,0 +1,40 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+# Configuration file for the Sphinx documentation builder.
+#
+# This file only contains a selection of the most common options. For a full
+# list see the documentation:
+# https://www.sphinx-doc.org/en/master/usage/configuration.html
+
+import os
+import subprocess
+
+project = "libbpf"
+
+extensions = [
+    'sphinx.ext.autodoc',
+    'sphinx.ext.doctest',
+    'sphinx.ext.mathjax',
+    'sphinx.ext.viewcode',
+    'sphinx.ext.imgmath',
+    'sphinx.ext.todo',
+    'breathe',
+]
+
+# List of patterns, relative to source directory, that match files and
+# directories to ignore when looking for source files.
+# This pattern also affects html_static_path and html_extra_path.
+exclude_patterns = []
+
+read_the_docs_build = os.environ.get('READTHEDOCS', None) == 'True'
+
+if read_the_docs_build:
+    subprocess.call('cd sphinx ; make clean', shell=True)
+    subprocess.call('cd sphinx/doxygen ; doxygen', shell=True)
+
+html_theme = 'sphinx_rtd_theme'
+
+breathe_projects = { "libbpf": "./sphinx/doxygen/build/xml/" }
+breathe_default_project = "libbpf"
+breathe_show_define_initializer = True
+breathe_show_enumvalue_initializer = True

docs/sphinx/Makefile

@@ -0,0 +1,9 @@
+SPHINXBUILD   ?= sphinx-build
+SOURCEDIR     = ../src
+BUILDDIR      = build
+
+help:
+	@$(SPHINXBUILD) -M help "$(SOURCEDIR)" "$(BUILDDIR)"
+
+%:
+	@$(SPHINXBUILD) -M $@ "$(SOURCEDIR)" "$(BUILDDIR)"

docs/sphinx/doxygen/Doxyfile

@@ -0,0 +1,277 @@
+DOXYFILE_ENCODING      = UTF-8
+PROJECT_NAME           = "libbpf"
+PROJECT_NUMBER         =
+PROJECT_BRIEF          =
+PROJECT_LOGO           =
+OUTPUT_DIRECTORY       = ./build
+CREATE_SUBDIRS         = NO
+ALLOW_UNICODE_NAMES    = NO
+OUTPUT_LANGUAGE        = English
+OUTPUT_TEXT_DIRECTION  = None
+BRIEF_MEMBER_DESC      = YES
+REPEAT_BRIEF           = YES
+ALWAYS_DETAILED_SEC    = NO
+INLINE_INHERITED_MEMB  = NO
+FULL_PATH_NAMES        = YES
+STRIP_FROM_PATH        =
+STRIP_FROM_INC_PATH    =
+SHORT_NAMES            = NO
+JAVADOC_AUTOBRIEF      = NO
+JAVADOC_BANNER         = NO
+QT_AUTOBRIEF           = NO
+MULTILINE_CPP_IS_BRIEF = NO
+PYTHON_DOCSTRING       = NO
+INHERIT_DOCS           = YES
+SEPARATE_MEMBER_PAGES  = NO
+TAB_SIZE               = 4
+ALIASES                =
+OPTIMIZE_OUTPUT_FOR_C  = YES
+OPTIMIZE_OUTPUT_JAVA   = NO
+OPTIMIZE_FOR_FORTRAN   = NO
+OPTIMIZE_OUTPUT_VHDL   = NO
+OPTIMIZE_OUTPUT_SLICE  = NO
+EXTENSION_MAPPING      =
+MARKDOWN_SUPPORT       = YES
+TOC_INCLUDE_HEADINGS   = 5
+AUTOLINK_SUPPORT       = YES
+BUILTIN_STL_SUPPORT    = NO
+CPP_CLI_SUPPORT        = NO
+SIP_SUPPORT            = NO
+IDL_PROPERTY_SUPPORT   = YES
+DISTRIBUTE_GROUP_DOC   = NO
+GROUP_NESTED_COMPOUNDS = NO
+SUBGROUPING            = YES
+INLINE_GROUPED_CLASSES = NO
+INLINE_SIMPLE_STRUCTS  = NO
+TYPEDEF_HIDES_STRUCT   = NO
+LOOKUP_CACHE_SIZE      = 0
+NUM_PROC_THREADS       = 1
+EXTRACT_ALL            = NO
+EXTRACT_PRIVATE        = NO
+EXTRACT_PRIV_VIRTUAL   = NO
+EXTRACT_PACKAGE        = NO
+EXTRACT_STATIC         = NO
+EXTRACT_LOCAL_CLASSES  = YES
+EXTRACT_LOCAL_METHODS  = NO
+EXTRACT_ANON_NSPACES   = NO
+RESOLVE_UNNAMED_PARAMS = YES
+HIDE_UNDOC_MEMBERS     = NO
+HIDE_UNDOC_CLASSES     = NO
+HIDE_FRIEND_COMPOUNDS  = NO
+HIDE_IN_BODY_DOCS      = NO
+INTERNAL_DOCS          = NO
+CASE_SENSE_NAMES       = YES
+HIDE_SCOPE_NAMES       = NO
+HIDE_COMPOUND_REFERENCE= NO
+SHOW_INCLUDE_FILES     = YES
+SHOW_GROUPED_MEMB_INC  = NO
+FORCE_LOCAL_INCLUDES   = NO
+INLINE_INFO            = YES
+SORT_MEMBER_DOCS       = YES
+SORT_BRIEF_DOCS        = NO
+SORT_MEMBERS_CTORS_1ST = NO
+SORT_GROUP_NAMES       = NO
+SORT_BY_SCOPE_NAME     = NO
+STRICT_PROTO_MATCHING  = NO
+GENERATE_TODOLIST      = YES
+GENERATE_TESTLIST      = YES
+GENERATE_BUGLIST       = YES
+GENERATE_DEPRECATEDLIST= YES
+ENABLED_SECTIONS       =
+MAX_INITIALIZER_LINES  = 30
+SHOW_USED_FILES        = YES
+SHOW_FILES             = YES
+SHOW_NAMESPACES        = YES
+FILE_VERSION_FILTER    =
+LAYOUT_FILE            =
+CITE_BIB_FILES         =
+QUIET                  = NO
+WARNINGS               = YES
+WARN_IF_UNDOCUMENTED   = YES
+WARN_IF_DOC_ERROR      = YES
+WARN_NO_PARAMDOC       = NO
+WARN_AS_ERROR          = NO
+WARN_FORMAT            = "$file:$line: $text"
+WARN_LOGFILE           =
+INPUT                  = ../../src
+INPUT_ENCODING         = UTF-8
+FILE_PATTERNS          = *.c \
+                         *.h
+RECURSIVE              = NO
+EXCLUDE                =
+EXCLUDE_SYMLINKS       = NO
+EXCLUDE_PATTERNS       =
+EXCLUDE_SYMBOLS        = ___*
+EXAMPLE_PATH           =
+EXAMPLE_PATTERNS       = *
+EXAMPLE_RECURSIVE      = NO
+IMAGE_PATH             =
+INPUT_FILTER           =
+FILTER_PATTERNS        =
+FILTER_SOURCE_FILES    = NO
+FILTER_SOURCE_PATTERNS =
+USE_MDFILE_AS_MAINPAGE = YES
+SOURCE_BROWSER         = NO
+INLINE_SOURCES         = NO
+STRIP_CODE_COMMENTS    = YES
+REFERENCED_BY_RELATION = NO
+REFERENCES_RELATION    = NO
+REFERENCES_LINK_SOURCE = YES
+SOURCE_TOOLTIPS        = YES
+USE_HTAGS              = NO
+VERBATIM_HEADERS       = YES
+ALPHABETICAL_INDEX     = YES
+IGNORE_PREFIX          =
+GENERATE_HTML          = NO
+HTML_OUTPUT            = html
+HTML_FILE_EXTENSION    = .html
+HTML_HEADER            =
+HTML_FOOTER            =
+HTML_STYLESHEET        =
+HTML_EXTRA_STYLESHEET  =
+HTML_EXTRA_FILES       =
+HTML_COLORSTYLE_HUE    = 220
+HTML_COLORSTYLE_SAT    = 100
+HTML_COLORSTYLE_GAMMA  = 80
+HTML_TIMESTAMP         = NO
+HTML_DYNAMIC_MENUS     = YES
+HTML_DYNAMIC_SECTIONS  = NO
+HTML_INDEX_NUM_ENTRIES = 100
+GENERATE_DOCSET        = NO
+DOCSET_FEEDNAME        = "Doxygen generated docs"
+DOCSET_BUNDLE_ID       = org.doxygen.Project
+DOCSET_PUBLISHER_ID    = org.doxygen.Publisher
+DOCSET_PUBLISHER_NAME  = Publisher
+GENERATE_HTMLHELP      = NO
+CHM_FILE               =
+HHC_LOCATION           =
+GENERATE_CHI           = NO
+CHM_INDEX_ENCODING     =
+BINARY_TOC             = NO
+TOC_EXPAND             = NO
+GENERATE_QHP           = NO
+QCH_FILE               =
+QHP_NAMESPACE          = org.doxygen.Project
+QHP_VIRTUAL_FOLDER     = doc
+QHP_CUST_FILTER_NAME   =
+QHP_CUST_FILTER_ATTRS  =
+QHP_SECT_FILTER_ATTRS  =
+QHG_LOCATION           =
+GENERATE_ECLIPSEHELP   = NO
+ECLIPSE_DOC_ID         = org.doxygen.Project
+DISABLE_INDEX          = NO
+GENERATE_TREEVIEW      = NO
+ENUM_VALUES_PER_LINE   = 4
+TREEVIEW_WIDTH         = 250
+EXT_LINKS_IN_WINDOW    = NO
+HTML_FORMULA_FORMAT    = png
+FORMULA_FONTSIZE       = 10
+FORMULA_TRANSPARENT    = YES
+FORMULA_MACROFILE      =
+USE_MATHJAX            = NO
+MATHJAX_FORMAT         = HTML-CSS
+MATHJAX_RELPATH        = https://cdn.jsdelivr.net/npm/mathjax@2
+MATHJAX_EXTENSIONS     =
+MATHJAX_CODEFILE       =
+SEARCHENGINE           = YES
+SERVER_BASED_SEARCH    = NO
+EXTERNAL_SEARCH        = NO
+SEARCHENGINE_URL       =
+SEARCHDATA_FILE        = searchdata.xml
+EXTERNAL_SEARCH_ID     =
+EXTRA_SEARCH_MAPPINGS  =
+GENERATE_LATEX         = NO
+LATEX_OUTPUT           = latex
+LATEX_CMD_NAME         =
+MAKEINDEX_CMD_NAME     = makeindex
+LATEX_MAKEINDEX_CMD    = makeindex
+COMPACT_LATEX          = NO
+PAPER_TYPE             = a4
+EXTRA_PACKAGES         =
+LATEX_HEADER           =
+LATEX_FOOTER           =
+LATEX_EXTRA_STYLESHEET =
+LATEX_EXTRA_FILES      =
+PDF_HYPERLINKS         = YES
+USE_PDFLATEX           = YES
+LATEX_BATCHMODE        = NO
+LATEX_HIDE_INDICES     = NO
+LATEX_SOURCE_CODE      = NO
+LATEX_BIB_STYLE        = plain
+LATEX_TIMESTAMP        = NO
+LATEX_EMOJI_DIRECTORY  =
+GENERATE_RTF           = NO
+RTF_OUTPUT             = rtf
+COMPACT_RTF            = NO
+RTF_HYPERLINKS         = NO
+RTF_STYLESHEET_FILE    =
+RTF_EXTENSIONS_FILE    =
+RTF_SOURCE_CODE        = NO
+GENERATE_MAN           = NO
+MAN_OUTPUT             = man
+MAN_EXTENSION          = .3
+MAN_SUBDIR             =
+MAN_LINKS              = NO
+GENERATE_XML           = YES
+XML_OUTPUT             = xml
+XML_PROGRAMLISTING     = YES
+XML_NS_MEMB_FILE_SCOPE = NO
+GENERATE_DOCBOOK       = NO
+DOCBOOK_OUTPUT         = docbook
+DOCBOOK_PROGRAMLISTING = NO
+GENERATE_AUTOGEN_DEF   = NO
+GENERATE_PERLMOD       = NO
+PERLMOD_LATEX          = NO
+PERLMOD_PRETTY         = YES
+PERLMOD_MAKEVAR_PREFIX =
+ENABLE_PREPROCESSING   = YES
+MACRO_EXPANSION        = NO
+EXPAND_ONLY_PREDEF     = YES
+SEARCH_INCLUDES        = YES
+INCLUDE_PATH           =
+INCLUDE_FILE_PATTERNS  =
+PREDEFINED             =
+EXPAND_AS_DEFINED      =
+SKIP_FUNCTION_MACROS   = NO
+TAGFILES               =
+GENERATE_TAGFILE       =
+ALLEXTERNALS           = NO
+EXTERNAL_GROUPS        = YES
+EXTERNAL_PAGES         = YES
+CLASS_DIAGRAMS         = YES
+DIA_PATH               =
+HIDE_UNDOC_RELATIONS   = YES
+HAVE_DOT               = NO
+DOT_NUM_THREADS        = 0
+DOT_FONTNAME           = Helvetica
+DOT_FONTSIZE           = 10
+DOT_FONTPATH           =
+CLASS_GRAPH            = YES
+COLLABORATION_GRAPH    = YES
+GROUP_GRAPHS           = YES
+UML_LOOK               = NO
+UML_LIMIT_NUM_FIELDS   = 10
+DOT_UML_DETAILS        = NO
+DOT_WRAP_THRESHOLD     = 17
+TEMPLATE_RELATIONS     = NO
+INCLUDE_GRAPH          = YES
+INCLUDED_BY_GRAPH      = YES
+CALL_GRAPH             = NO
+CALLER_GRAPH           = NO
+GRAPHICAL_HIERARCHY    = YES
+DIRECTORY_GRAPH        = YES
+DOT_IMAGE_FORMAT       = png
+INTERACTIVE_SVG        = NO
+DOT_PATH               =
+DOTFILE_DIRS           =
+MSCFILE_DIRS           =
+DIAFILE_DIRS           =
+PLANTUML_JAR_PATH      =
+PLANTUML_CFG_FILE      =
+PLANTUML_INCLUDE_PATH  =
+DOT_GRAPH_MAX_NODES    = 50
+MAX_DOT_GRAPH_DEPTH    = 0
+DOT_TRANSPARENT        = NO
+DOT_MULTI_TARGETS      = NO
+GENERATE_LEGEND        = YES
+DOT_CLEANUP            = YES

docs/sphinx/requirements.txt

@@ -0,0 +1 @@
+breathe

scripts/sync-kernel.sh

@@ -47,6 +47,7 @@ PATH_MAP=(									\
 	[tools/include/uapi/linux/netlink.h]=include/uapi/linux/netlink.h	\
 	[tools/include/uapi/linux/pkt_cls.h]=include/uapi/linux/pkt_cls.h	\
 	[tools/include/uapi/linux/pkt_sched.h]=include/uapi/linux/pkt_sched.h	\
+	[Documentation/bpf/libbpf]=src/docs					\
 )
 
 LIBBPF_PATHS="${!PATH_MAP[@]} :^tools/lib/bpf/Makefile :^tools/lib/bpf/Build :^tools/lib/bpf/.gitignore :^tools/include/tools/libc_compat.h"