#!/usr/bin/env python3
# xxpylint: disable=R0903
# Copyright(c) 2025: Mauro Carvalho Chehab <mchehab@kernel.org>.
# SPDX-License-Identifier: GPL-2.0
"""
Convert ABI what into regular expressions
"""
import re
import sys
from pprint import pformat
from abi_parser import AbiParser
from helpers import AbiDebug
class AbiRegex(AbiParser):
"""Extends AbiParser to search ABI nodes with regular expressions"""
# Escape only ASCII visible characters
escape_symbols = r"([\x21-\x29\x2b-\x2d\x3a-\x40\x5c\x60\x7b-\x7e])"
leave_others = "others"
# Tuples with regular expressions to be compiled and replacement data
re_whats = [
# Drop escape characters that might exist
(re.compile("\\\\"), ""),
# Temporarily escape dot characters
(re.compile(r"\."), "\xf6"),
# Temporarily change [0-9]+ type of patterns
(re.compile(r"\[0\-9\]\+"), "\xff"),
# Temporarily change [\d+-\d+] type of patterns
(re.compile(r"\[0\-\d+\]"), "\xff"),
(re.compile(r"\[0:\d+\]"), "\xff"),
(re.compile(r"\[(\d+)\]"), "\xf4\\\\d+\xf5"),
# Temporarily change [0-9] type of patterns
(re.compile(r"\[(\d)\-(\d)\]"), "\xf4\1-\2\xf5"),
# Handle multiple option patterns
(re.compile(r"[\{\<\[]([\w_]+)(?:[,|]+([\w_]+)){1,}[\}\>\]]"), r"(\1|\2)"),
# Handle wildcards
(re.compile(r"([^\/])\*"), "\\1\\\\w\xf7"),
(re.compile(r"/\*/"), "/.*/"),
(re.compile(r"/\xf6\xf6\xf6"), "/.*"),
(re.compile(r"\<[^\>]+\>"), "\\\\w\xf7"),
(re.compile(r"\{[^\}]+\}"), "\\\\w\xf7"),
(re.compile(r"\[[^\]]+\]"), "\\\\w\xf7"),
(re.compile(r"XX+"), "\\\\w\xf7"),
(re.compile(r"([^A-Z])[XYZ]([^A-Z])"), "\\1\\\\w\xf7\\2"),
(re.compile(r"([^A-Z])[XYZ]$"), "\\1\\\\w\xf7"),
(re.compile(r"_[AB]_"), "_\\\\w\xf7_"),
# Recover [0-9] type of patterns
(re.compile(r"\xf4"), "["),
(re.compile(r"\xf5"), "]"),
# Remove duplicated spaces
(re.compile(r"\s+"), r" "),
# Special case: drop comparison as in:
# What: foo = <something>
# (this happens on a few IIO definitions)
(re.compile(r"\s*\=.*$"), ""),
# Escape all other symbols
(re.compile(escape_symbols), r"\\\1"),
(re.compile(r"\\\\"), r"\\"),
(re.compile(r"\\([\[\]\(\)\|])"), r"\1"),
(re.compile(r"(\d+)\\(-\d+)"), r"\1\2"),
(re.compile(r"\xff"), r"\\d+"),
# Special case: IIO ABI which a parenthesis.
(re.compile(r"sqrt(.*)"), r"sqrt(.*)"),
# Simplify regexes with multiple .*
(re.compile(r"(?:\.\*){2,}"), ""),
# Recover dot characters
(re.compile(r"\xf6"), "\\."),
# Recover plus characters
(re.compile(r"\xf7"), "+"),
]
re_has_num = re.compile(r"\\d")
# Symbol name after escape_chars that are considered a devnode basename
re_symbol_name = re.compile(r"(\w|\\[\.\-\:])+$")
# List of popular group names to be skipped to minimize regex group size
# Use AbiDebug.SUBGROUP_SIZE to detect those
skip_names = set(["devices", "hwmon"])
def regex_append(self, what, new):
"""
Get a search group for a subset of regular expressions.
As ABI may have thousands of symbols, using a for to search all
regular expressions is at least O(n^2). When there are wildcards,
the complexity increases substantially, eventually becoming exponential.
To avoid spending too much time on them, use a logic to split
them into groups. The smaller the group, the better, as it would
mean that searches will be confined to a small number of regular
expressions.
The conversion to a regex subset is tricky, as we need something
that can be easily obtained from the sysfs symbol and from the
regular expression. So, we need to discard nodes that have
wildcards.
If it can't obtain a subgroup, place the regular expression inside
a special group (self.leave_others).
"""
search_group = None
for search_group in reversed(new.split("/")):
if not search_group or search_group in self.skip_names:
continue
if self.re_symbol_name.match(search_group):
break
if not search_group:
search_group = self.leave_others
if self.debug & AbiDebug.SUBGROUP_MAP:
self.log.debug("%s: mapped as %s", what, search_group)
try:
if search_group not in self.regex_group:
self.regex_group[search_group] = []
self.regex_group[search_group].append(re.compile(new))
if self.search_string:
if what.find(self.search_string) >= 0:
print(f"What: {what}")
except re.PatternError:
self.log.warning("Ignoring '%s' as it produced an invalid regex:\n"
" '%s'", what, new)
def get_regexes(self, what):
"""
Given an ABI devnode, return a list of all regular expressions that
may match it, based on the sub-groups created by regex_append()
"""
re_list = []
patches = what.split("/")
patches.reverse()
patches.append(self.leave_others)
for search_group in patches:
if search_group in self.regex_group:
re_list += self.regex_group[search_group]
return re_list
def __init__(self, *args, **kwargs):
"""
Override init method to get verbose argument
"""
self.regex_group = None
self.search_string = None
self.re_string = None
if "search_string" in kwargs:
self.search_string = kwargs.get("search_string")
del kwargs["search_string"]
if self.search_string:
try:
self.re_string = re.compile(self.search_string)
except re.PatternError as e:
msg = f"{self.search_string} is not a valid regular expression"
raise ValueError(msg) from e
super().__init__(*args, **kwargs)
def parse_abi(self, *args, **kwargs):
super().parse_abi(*args, **kwargs)
self.regex_group = {}
print("Converting ABI What fields into regexes...", file=sys.stderr)
for t in sorted(self.data.items(), key=lambda x: x[0]):
v = t[1]
if v.get("type") == "File":
continue
v["regex"] = []
for what in v.get("what", []):
if not what.startswith("/sys"):
continue
new = what
for r, s in self.re_whats:
try:
new = r.sub(s, new)
except re.PatternError as e:
# Help debugging troubles with new regexes
raise re.PatternError(f"{e}\nwhile re.sub('{r.pattern}', {s}, str)") from e
v["regex"].append(new)
if self.debug & AbiDebug.REGEX:
self.log.debug("%-90s <== %s", new, what)
# Store regex into a subgroup to speedup searches
self.regex_append(what, new)
if self.debug & AbiDebug.SUBGROUP_DICT:
self.log.debug("%s", pformat(self.regex_group))
if self.debug & AbiDebug.SUBGROUP_SIZE:
biggestd_keys = sorted(self.regex_group.keys(),
key= lambda k: len(self.regex_group[k]),
reverse=True)
print("Top regex subgroups:", file=sys.stderr)
for k in biggestd_keys[:10]:
print(f"{k} has {len(self.regex_group[k])} elements", file=sys.stderr)