scripts: Import Python kerneldoc from Linux kernel

We last synced our copy of kerneldoc with Linux back in 2020.  In the
interim, upstream has entirely rewritten the script in Python, and
the new Python version is split into a main script plus some
libraries in the kernel's scripts/lib/kdoc.

Import all these files.  These are the versions as of kernel commit
0cc53520e68be, with no local changes.

We use the same lib/kdoc/ directory as the kernel does here, so we
can avoid having to edit the top-level script just to adjust a
pathname, even though it is probably not the naming we would have
picked if this was a purely QEMU script.

The Sphinx conf.py still points at the Perl version of the script,
so this Python code will not be invoked to build the docs yet.

NB: checkpatch complains about many things in this commit,
including the use of "GPL-2.0" rather than "GPL-2.0-only" in
the SPDX tags, but since this is a third party import we can
ignore this.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Message-id: 20250814171324.1614516-4-peter.maydell@linaro.org

1 files changed, 291 insertions, 0 deletions

diff --git a/scripts/lib/kdoc/kdoc_files.py b/scripts/lib/kdoc/kdoc_files.py
new file mode 100644
index 0000000..9e09b45
--- /dev/null
+++ b/scripts/lib/kdoc/kdoc_files.py
@@ -0,0 +1,291 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+# Copyright(c) 2025: Mauro Carvalho Chehab <mchehab@kernel.org>.
+#
+# pylint: disable=R0903,R0913,R0914,R0917
+
+"""
+Parse lernel-doc tags on multiple kernel source files.
+"""
+
+import argparse
+import logging
+import os
+import re
+
+from kdoc_parser import KernelDoc
+from kdoc_output import OutputFormat
+
+
+class GlobSourceFiles:
+    """
+    Parse C source code file names and directories via an Interactor.
+    """
+
+    def __init__(self, srctree=None, valid_extensions=None):
+        """
+        Initialize valid extensions with a tuple.
+
+        If not defined, assume default C extensions (.c and .h)
+
+        It would be possible to use python's glob function, but it is
+        very slow, and it is not interactive. So, it would wait to read all
+        directories before actually do something.
+
+        So, let's use our own implementation.
+        """
+
+        if not valid_extensions:
+            self.extensions = (".c", ".h")
+        else:
+            self.extensions = valid_extensions
+
+        self.srctree = srctree
+
+    def _parse_dir(self, dirname):
+        """Internal function to parse files recursively"""
+
+        with os.scandir(dirname) as obj:
+            for entry in obj:
+                name = os.path.join(dirname, entry.name)
+
+                if entry.is_dir():
+                    yield from self._parse_dir(name)
+
+                if not entry.is_file():
+                    continue
+
+                basename = os.path.basename(name)
+
+                if not basename.endswith(self.extensions):
+                    continue
+
+                yield name
+
+    def parse_files(self, file_list, file_not_found_cb):
+        """
+        Define an interator to parse all source files from file_list,
+        handling directories if any
+        """
+
+        if not file_list:
+            return
+
+        for fname in file_list:
+            if self.srctree:
+                f = os.path.join(self.srctree, fname)
+            else:
+                f = fname
+
+            if os.path.isdir(f):
+                yield from self._parse_dir(f)
+            elif os.path.isfile(f):
+                yield f
+            elif file_not_found_cb:
+                file_not_found_cb(fname)
+
+
+class KernelFiles():
+    """
+    Parse kernel-doc tags on multiple kernel source files.
+
+    There are two type of parsers defined here:
+        - self.parse_file(): parses both kernel-doc markups and
+          EXPORT_SYMBOL* macros;
+        - self.process_export_file(): parses only EXPORT_SYMBOL* macros.
+    """
+
+    def warning(self, msg):
+        """Ancillary routine to output a warning and increment error count"""
+
+        self.config.log.warning(msg)
+        self.errors += 1
+
+    def error(self, msg):
+        """Ancillary routine to output an error and increment error count"""
+
+        self.config.log.error(msg)
+        self.errors += 1
+
+    def parse_file(self, fname):
+        """
+        Parse a single Kernel source.
+        """
+
+        # Prevent parsing the same file twice if results are cached
+        if fname in self.files:
+            return
+
+        doc = KernelDoc(self.config, fname)
+        export_table, entries = doc.parse_kdoc()
+
+        self.export_table[fname] = export_table
+
+        self.files.add(fname)
+        self.export_files.add(fname)      # parse_kdoc() already check exports
+
+        self.results[fname] = entries
+
+    def process_export_file(self, fname):
+        """
+        Parses EXPORT_SYMBOL* macros from a single Kernel source file.
+        """
+
+        # Prevent parsing the same file twice if results are cached
+        if fname in self.export_files:
+            return
+
+        doc = KernelDoc(self.config, fname)
+        export_table = doc.parse_export()
+
+        if not export_table:
+            self.error(f"Error: Cannot check EXPORT_SYMBOL* on {fname}")
+            export_table = set()
+
+        self.export_table[fname] = export_table
+        self.export_files.add(fname)
+
+    def file_not_found_cb(self, fname):
+        """
+        Callback to warn if a file was not found.
+        """
+
+        self.error(f"Cannot find file {fname}")
+
+    def __init__(self, verbose=False, out_style=None,
+                 werror=False, wreturn=False, wshort_desc=False,
+                 wcontents_before_sections=False,
+                 logger=None):
+        """
+        Initialize startup variables and parse all files
+        """
+
+        if not verbose:
+            verbose = bool(os.environ.get("KBUILD_VERBOSE", 0))
+
+        if out_style is None:
+            out_style = OutputFormat()
+
+        if not werror:
+            kcflags = os.environ.get("KCFLAGS", None)
+            if kcflags:
+                match = re.search(r"(\s|^)-Werror(\s|$)/", kcflags)
+                if match:
+                    werror = True
+
+            # reading this variable is for backwards compat just in case
+            # someone was calling it with the variable from outside the
+            # kernel's build system
+            kdoc_werror = os.environ.get("KDOC_WERROR", None)
+            if kdoc_werror:
+                werror = kdoc_werror
+
+        # Some variables are global to the parser logic as a whole as they are
+        # used to send control configuration to KernelDoc class. As such,
+        # those variables are read-only inside the KernelDoc.
+        self.config = argparse.Namespace
+
+        self.config.verbose = verbose
+        self.config.werror = werror
+        self.config.wreturn = wreturn
+        self.config.wshort_desc = wshort_desc
+        self.config.wcontents_before_sections = wcontents_before_sections
+
+        if not logger:
+            self.config.log = logging.getLogger("kernel-doc")
+        else:
+            self.config.log = logger
+
+        self.config.warning = self.warning
+
+        self.config.src_tree = os.environ.get("SRCTREE", None)
+
+        # Initialize variables that are internal to KernelFiles
+
+        self.out_style = out_style
+
+        self.errors = 0
+        self.results = {}
+
+        self.files = set()
+        self.export_files = set()
+        self.export_table = {}
+
+    def parse(self, file_list, export_file=None):
+        """
+        Parse all files
+        """
+
+        glob = GlobSourceFiles(srctree=self.config.src_tree)
+
+        for fname in glob.parse_files(file_list, self.file_not_found_cb):
+            self.parse_file(fname)
+
+        for fname in glob.parse_files(export_file, self.file_not_found_cb):
+            self.process_export_file(fname)
+
+    def out_msg(self, fname, name, arg):
+        """
+        Return output messages from a file name using the output style
+        filtering.
+
+        If output type was not handled by the syler, return None.
+        """
+
+        # NOTE: we can add rules here to filter out unwanted parts,
+        # although OutputFormat.msg already does that.
+
+        return self.out_style.msg(fname, name, arg)
+
+    def msg(self, enable_lineno=False, export=False, internal=False,
+            symbol=None, nosymbol=None, no_doc_sections=False,
+            filenames=None, export_file=None):
+        """
+        Interacts over the kernel-doc results and output messages,
+        returning kernel-doc markups on each interaction
+        """
+
+        self.out_style.set_config(self.config)
+
+        if not filenames:
+            filenames = sorted(self.results.keys())
+
+        glob = GlobSourceFiles(srctree=self.config.src_tree)
+
+        for fname in filenames:
+            function_table = set()
+
+            if internal or export:
+                if not export_file:
+                    export_file = [fname]
+
+                for f in glob.parse_files(export_file, self.file_not_found_cb):
+                    function_table |= self.export_table[f]
+
+            if symbol:
+                for s in symbol:
+                    function_table.add(s)
+
+            self.out_style.set_filter(export, internal, symbol, nosymbol,
+                                      function_table, enable_lineno,
+                                      no_doc_sections)
+
+            msg = ""
+            if fname not in self.results:
+                self.config.log.warning("No kernel-doc for file %s", fname)
+                continue
+
+            for arg in self.results[fname]:
+                m = self.out_msg(fname, arg.name, arg)
+
+                if m is None:
+                    ln = arg.get("ln", 0)
+                    dtype = arg.get('type', "")
+
+                    self.config.log.warning("%s:%d Can't handle %s",
+                                            fname, ln, dtype)
+                else:
+                    msg += m
+
+            if msg:
+                yield fname, msg