Copy check_names.py and friends from development

Copy the following files:
    tests/scripts/check_names.py
    tests/scripts/list_internal_identifiers.py
    tests/scripts/list-identifiers.sh

Copy the version from b19be6b5f3c9a92b5b17fa27e16901f132f1a310, which is the
result of merging https://github.com/ARMmbed/mbedtls/pull/1638 into the
development branch.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/tests/scripts/check_names.py b/tests/scripts/check_names.py
new file mode 100755
index 0000000..a9aa118
--- /dev/null
+++ b/tests/scripts/check_names.py
@@ -0,0 +1,865 @@
+#!/usr/bin/env python3
+#
+# Copyright The Mbed TLS Contributors
+# SPDX-License-Identifier: Apache-2.0
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""
+This script confirms that the naming of all symbols and identifiers in Mbed TLS
+are consistent with the house style and are also self-consistent. It only runs
+on Linux and macOS since it depends on nm.
+
+It contains two major Python classes, CodeParser and NameChecker. They both have
+a comprehensive "run-all" function (comprehensive_parse() and perform_checks())
+but the individual functions can also be used for specific needs.
+
+CodeParser makes heavy use of regular expressions to parse the code, and is
+dependent on the current code formatting. Many Python C parser libraries require
+preprocessed C code, which means no macro parsing. Compiler tools are also not
+very helpful when we want the exact location in the original source (which
+becomes impossible when e.g. comments are stripped).
+
+NameChecker performs the following checks:
+
+- All exported and available symbols in the library object files, are explicitly
+  declared in the header files. This uses the nm command.
+- All macros, constants, and identifiers (function names, struct names, etc)
+  follow the required regex pattern.
+- Typo checking: All words that begin with MBED exist as macros or constants.
+
+The script returns 0 on success, 1 on test failure, and 2 if there is a script
+error. It must be run from Mbed TLS root.
+"""
+
+import abc
+import argparse
+import glob
+import textwrap
+import os
+import sys
+import traceback
+import re
+import enum
+import shutil
+import subprocess
+import logging
+
+# Naming patterns to check against. These are defined outside the NameCheck
+# class for ease of modification.
+MACRO_PATTERN = r"^(MBEDTLS|PSA)_[0-9A-Z_]*[0-9A-Z]$"
+CONSTANTS_PATTERN = MACRO_PATTERN
+IDENTIFIER_PATTERN = r"^(mbedtls|psa)_[0-9a-z_]*[0-9a-z]$"
+
+class Match(): # pylint: disable=too-few-public-methods
+    """
+    A class representing a match, together with its found position.
+
+    Fields:
+    * filename: the file that the match was in.
+    * line: the full line containing the match.
+    * line_no: the line number.
+    * pos: a tuple of (start, end) positions on the line where the match is.
+    * name: the match itself.
+    """
+    def __init__(self, filename, line, line_no, pos, name):
+        # pylint: disable=too-many-arguments
+        self.filename = filename
+        self.line = line
+        self.line_no = line_no
+        self.pos = pos
+        self.name = name
+
+    def __str__(self):
+        """
+        Return a formatted code listing representation of the erroneous line.
+        """
+        gutter = format(self.line_no, "4d")
+        underline = self.pos[0] * " " + (self.pos[1] - self.pos[0]) * "^"
+
+        return (
+            " {0} |\n".format(" " * len(gutter)) +
+            " {0} | {1}".format(gutter, self.line) +
+            " {0} | {1}\n".format(" " * len(gutter), underline)
+        )
+
+class Problem(abc.ABC): # pylint: disable=too-few-public-methods
+    """
+    An abstract parent class representing a form of static analysis error.
+    It extends an Abstract Base Class, which means it is not instantiable, and
+    it also mandates certain abstract methods to be implemented in subclasses.
+    """
+    # Class variable to control the quietness of all problems
+    quiet = False
+    def __init__(self):
+        self.textwrapper = textwrap.TextWrapper()
+        self.textwrapper.width = 80
+        self.textwrapper.initial_indent = "    > "
+        self.textwrapper.subsequent_indent = "      "
+
+    def __str__(self):
+        """
+        Unified string representation method for all Problems.
+        """
+        if self.__class__.quiet:
+            return self.quiet_output()
+        return self.verbose_output()
+
+    @abc.abstractmethod
+    def quiet_output(self):
+        """
+        The output when --quiet is enabled.
+        """
+        pass
+
+    @abc.abstractmethod
+    def verbose_output(self):
+        """
+        The default output with explanation and code snippet if appropriate.
+        """
+        pass
+
+class SymbolNotInHeader(Problem): # pylint: disable=too-few-public-methods
+    """
+    A problem that occurs when an exported/available symbol in the object file
+    is not explicitly declared in header files. Created with
+    NameCheck.check_symbols_declared_in_header()
+
+    Fields:
+    * symbol_name: the name of the symbol.
+    """
+    def __init__(self, symbol_name):
+        self.symbol_name = symbol_name
+        Problem.__init__(self)
+
+    def quiet_output(self):
+        return "{0}".format(self.symbol_name)
+
+    def verbose_output(self):
+        return self.textwrapper.fill(
+            "'{0}' was found as an available symbol in the output of nm, "
+            "however it was not declared in any header files."
+            .format(self.symbol_name))
+
+class PatternMismatch(Problem): # pylint: disable=too-few-public-methods
+    """
+    A problem that occurs when something doesn't match the expected pattern.
+    Created with NameCheck.check_match_pattern()
+
+    Fields:
+    * pattern: the expected regex pattern
+    * match: the Match object in question
+    """
+    def __init__(self, pattern, match):
+        self.pattern = pattern
+        self.match = match
+        Problem.__init__(self)
+
+
+    def quiet_output(self):
+        return (
+            "{0}:{1}:{2}"
+            .format(self.match.filename, self.match.line_no, self.match.name)
+        )
+
+    def verbose_output(self):
+        return self.textwrapper.fill(
+            "{0}:{1}: '{2}' does not match the required pattern '{3}'."
+            .format(
+                self.match.filename,
+                self.match.line_no,
+                self.match.name,
+                self.pattern
+            )
+        ) + "\n" + str(self.match)
+
+class Typo(Problem): # pylint: disable=too-few-public-methods
+    """
+    A problem that occurs when a word using MBED doesn't appear to be defined as
+    constants nor enum values. Created with NameCheck.check_for_typos()
+
+    Fields:
+    * match: the Match object of the MBED name in question.
+    """
+    def __init__(self, match):
+        self.match = match
+        Problem.__init__(self)
+
+    def quiet_output(self):
+        return (
+            "{0}:{1}:{2}"
+            .format(self.match.filename, self.match.line_no, self.match.name)
+        )
+
+    def verbose_output(self):
+        return self.textwrapper.fill(
+            "{0}:{1}: '{2}' looks like a typo. It was not found in any "
+            "macros or any enums. If this is not a typo, put "
+            "//no-check-names after it."
+            .format(self.match.filename, self.match.line_no, self.match.name)
+        ) + "\n" + str(self.match)
+
+class CodeParser():
+    """
+    Class for retrieving files and parsing the code. This can be used
+    independently of the checks that NameChecker performs, for example for
+    list_internal_identifiers.py.
+    """
+    def __init__(self, log):
+        self.log = log
+        self.check_repo_path()
+
+        # Memo for storing "glob expression": set(filepaths)
+        self.files = {}
+
+        # Globally excluded filenames
+        self.excluded_files = ["**/bn_mul", "**/compat-2.x.h"]
+
+    @staticmethod
+    def check_repo_path():
+        """
+        Check that the current working directory is the project root, and throw
+        an exception if not.
+        """
+        if not all(os.path.isdir(d) for d in ["include", "library", "tests"]):
+            raise Exception("This script must be run from Mbed TLS root")
+
+    def comprehensive_parse(self):
+        """
+        Comprehensive ("default") function to call each parsing function and
+        retrieve various elements of the code, together with the source location.
+
+        Returns a dict of parsed item key to the corresponding List of Matches.
+        """
+        self.log.info("Parsing source code...")
+        self.log.debug(
+            "The following files are excluded from the search: {}"
+            .format(str(self.excluded_files))
+        )
+
+        all_macros = self.parse_macros([
+            "include/mbedtls/*.h",
+            "include/psa/*.h",
+            "library/*.h",
+            "tests/include/test/drivers/*.h",
+            "3rdparty/everest/include/everest/everest.h",
+            "3rdparty/everest/include/everest/x25519.h"
+        ])
+        enum_consts = self.parse_enum_consts([
+            "include/mbedtls/*.h",
+            "library/*.h",
+            "3rdparty/everest/include/everest/everest.h",
+            "3rdparty/everest/include/everest/x25519.h"
+        ])
+        identifiers = self.parse_identifiers([
+            "include/mbedtls/*.h",
+            "include/psa/*.h",
+            "library/*.h",
+            "3rdparty/everest/include/everest/everest.h",
+            "3rdparty/everest/include/everest/x25519.h"
+        ])
+        mbed_words = self.parse_mbed_words([
+            "include/mbedtls/*.h",
+            "include/psa/*.h",
+            "library/*.h",
+            "3rdparty/everest/include/everest/everest.h",
+            "3rdparty/everest/include/everest/x25519.h",
+            "library/*.c",
+            "3rdparty/everest/library/everest.c",
+            "3rdparty/everest/library/x25519.c"
+        ])
+        symbols = self.parse_symbols()
+
+        # Remove identifier macros like mbedtls_printf or mbedtls_calloc
+        identifiers_justname = [x.name for x in identifiers]
+        actual_macros = []
+        for macro in all_macros:
+            if macro.name not in identifiers_justname:
+                actual_macros.append(macro)
+
+        self.log.debug("Found:")
+        # Aligns the counts on the assumption that none exceeds 4 digits
+        self.log.debug("  {:4} Total Macros".format(len(all_macros)))
+        self.log.debug("  {:4} Non-identifier Macros".format(len(actual_macros)))
+        self.log.debug("  {:4} Enum Constants".format(len(enum_consts)))
+        self.log.debug("  {:4} Identifiers".format(len(identifiers)))
+        self.log.debug("  {:4} Exported Symbols".format(len(symbols)))
+        return {
+            "macros": actual_macros,
+            "enum_consts": enum_consts,
+            "identifiers": identifiers,
+            "symbols": symbols,
+            "mbed_words": mbed_words
+        }
+
+    def get_files(self, include_wildcards, exclude_wildcards):
+        """
+        Get all files that match any of the UNIX-style wildcards. While the
+        check_names script is designed only for use on UNIX/macOS (due to nm),
+        this function alone would work fine on Windows even with forward slashes
+        in the wildcard.
+
+        Args:
+        * include_wildcards: a List of shell-style wildcards to match filepaths.
+        * exclude_wildcards: a List of shell-style wildcards to exclude.
+
+        Returns a List of relative filepaths.
+        """
+        accumulator = set()
+
+        # exclude_wildcards may be None. Also, consider the global exclusions.
+        exclude_wildcards = (exclude_wildcards or []) + self.excluded_files
+
+        # Internal function to hit the memoisation cache or add to it the result
+        # of a glob operation. Used both for inclusion and exclusion since the
+        # only difference between them is whether they perform set union or
+        # difference on the return value of this function.
+        def hit_cache(wildcard):
+            if wildcard not in self.files:
+                self.files[wildcard] = set(glob.glob(wildcard, recursive=True))
+            return self.files[wildcard]
+
+        for include_wildcard in include_wildcards:
+            accumulator = accumulator.union(hit_cache(include_wildcard))
+
+        for exclude_wildcard in exclude_wildcards:
+            accumulator = accumulator.difference(hit_cache(exclude_wildcard))
+
+        return list(accumulator)
+
+    def parse_macros(self, include, exclude=None):
+        """
+        Parse all macros defined by #define preprocessor directives.
+
+        Args:
+        * include: A List of glob expressions to look for files through.
+        * exclude: A List of glob expressions for excluding files.
+
+        Returns a List of Match objects for the found macros.
+        """
+        macro_regex = re.compile(r"# *define +(?P<macro>\w+)")
+        exclusions = (
+            "asm", "inline", "EMIT", "_CRT_SECURE_NO_DEPRECATE", "MULADDC_"
+        )
+
+        files = self.get_files(include, exclude)
+        self.log.debug("Looking for macros in {} files".format(len(files)))
+
+        macros = []
+        for header_file in files:
+            with open(header_file, "r", encoding="utf-8") as header:
+                for line_no, line in enumerate(header):
+                    for macro in macro_regex.finditer(line):
+                        if macro.group("macro").startswith(exclusions):
+                            continue
+
+                        macros.append(Match(
+                            header_file,
+                            line,
+                            line_no,
+                            macro.span("macro"),
+                            macro.group("macro")))
+
+        return macros
+
+    def parse_mbed_words(self, include, exclude=None):
+        """
+        Parse all words in the file that begin with MBED, in and out of macros,
+        comments, anything.
+
+        Args:
+        * include: A List of glob expressions to look for files through.
+        * exclude: A List of glob expressions for excluding files.
+
+        Returns a List of Match objects for words beginning with MBED.
+        """
+        # Typos of TLS are common, hence the broader check below than MBEDTLS.
+        mbed_regex = re.compile(r"\bMBED.+?_[A-Z0-9_]*")
+        exclusions = re.compile(r"// *no-check-names|#error")
+
+        files = self.get_files(include, exclude)
+        self.log.debug("Looking for MBED words in {} files".format(len(files)))
+
+        mbed_words = []
+        for filename in files:
+            with open(filename, "r", encoding="utf-8") as fp:
+                for line_no, line in enumerate(fp):
+                    if exclusions.search(line):
+                        continue
+
+                    for name in mbed_regex.finditer(line):
+                        mbed_words.append(Match(
+                            filename,
+                            line,
+                            line_no,
+                            name.span(0),
+                            name.group(0)))
+
+        return mbed_words
+
+    def parse_enum_consts(self, include, exclude=None):
+        """
+        Parse all enum value constants that are declared.
+
+        Args:
+        * include: A List of glob expressions to look for files through.
+        * exclude: A List of glob expressions for excluding files.
+
+        Returns a List of Match objects for the findings.
+        """
+        files = self.get_files(include, exclude)
+        self.log.debug("Looking for enum consts in {} files".format(len(files)))
+
+        # Emulate a finite state machine to parse enum declarations.
+        # OUTSIDE_KEYWORD = outside the enum keyword
+        # IN_BRACES = inside enum opening braces
+        # IN_BETWEEN = between enum keyword and opening braces
+        states = enum.Enum("FSM", ["OUTSIDE_KEYWORD", "IN_BRACES", "IN_BETWEEN"])
+        enum_consts = []
+        for header_file in files:
+            state = states.OUTSIDE_KEYWORD
+            with open(header_file, "r", encoding="utf-8") as header:
+                for line_no, line in enumerate(header):
+                    # Match typedefs and brackets only when they are at the
+                    # beginning of the line -- if they are indented, they might
+                    # be sub-structures within structs, etc.
+                    if (state == states.OUTSIDE_KEYWORD and
+                            re.search(r"^(typedef +)?enum +{", line)):
+                        state = states.IN_BRACES
+                    elif (state == states.OUTSIDE_KEYWORD and
+                          re.search(r"^(typedef +)?enum", line)):
+                        state = states.IN_BETWEEN
+                    elif (state == states.IN_BETWEEN and
+                          re.search(r"^{", line)):
+                        state = states.IN_BRACES
+                    elif (state == states.IN_BRACES and
+                          re.search(r"^}", line)):
+                        state = states.OUTSIDE_KEYWORD
+                    elif (state == states.IN_BRACES and
+                          not re.search(r"^ *#", line)):
+                        enum_const = re.search(r"^ *(?P<enum_const>\w+)", line)
+                        if not enum_const:
+                            continue
+
+                        enum_consts.append(Match(
+                            header_file,
+                            line,
+                            line_no,
+                            enum_const.span("enum_const"),
+                            enum_const.group("enum_const")))
+
+        return enum_consts
+
+    def parse_identifiers(self, include, exclude=None):
+        """
+        Parse all lines of a header where a function/enum/struct/union/typedef
+        identifier is declared, based on some regex and heuristics. Highly
+        dependent on formatting style.
+
+        Args:
+        * include: A List of glob expressions to look for files through.
+        * exclude: A List of glob expressions for excluding files.
+
+        Returns a List of Match objects with identifiers.
+        """
+        identifier_regex = re.compile(
+            # Match " something(a" or " *something(a". Functions.
+            # Assumptions:
+            # - function definition from return type to one of its arguments is
+            #   all on one line
+            # - function definition line only contains alphanumeric, asterisk,
+            #   underscore, and open bracket
+            r".* \**(\w+) *\( *\w|"
+            # Match "(*something)(".
+            r".*\( *\* *(\w+) *\) *\(|"
+            # Match names of named data structures.
+            r"(?:typedef +)?(?:struct|union|enum) +(\w+)(?: *{)?$|"
+            # Match names of typedef instances, after closing bracket.
+            r"}? *(\w+)[;[].*"
+        )
+        # The regex below is indented for clarity.
+        exclusion_lines = re.compile(
+            r"^("
+                r"extern +\"C\"|" # pylint: disable=bad-continuation
+                r"(typedef +)?(struct|union|enum)( *{)?$|"
+                r"} *;?$|"
+                r"$|"
+                r"//|"
+                r"#"
+            r")"
+        )
+
+        files = self.get_files(include, exclude)
+        self.log.debug("Looking for identifiers in {} files".format(len(files)))
+
+        identifiers = []
+        for header_file in files:
+            with open(header_file, "r", encoding="utf-8") as header:
+                in_block_comment = False
+                # The previous line variable is used for concatenating lines
+                # when identifiers are formatted and spread across multiple
+                # lines.
+                previous_line = ""
+
+                for line_no, line in enumerate(header):
+                    # Skip parsing this line if a block comment ends on it,
+                    # but don't skip if it has just started -- there is a chance
+                    # it ends on the same line.
+                    if re.search(r"/\*", line):
+                        in_block_comment = not in_block_comment
+                    if re.search(r"\*/", line):
+                        in_block_comment = not in_block_comment
+                        continue
+
+                    if in_block_comment:
+                        previous_line = ""
+                        continue
+
+                    if exclusion_lines.search(line):
+                        previous_line = ""
+                        continue
+
+                    # If the line contains only space-separated alphanumeric
+                    # characters (or underscore, asterisk, or, open bracket),
+                    # and nothing else, high chance it's a declaration that
+                    # continues on the next line
+                    if re.search(r"^([\w\*\(]+\s+)+$", line):
+                        previous_line += line
+                        continue
+
+                    # If previous line seemed to start an unfinished declaration
+                    # (as above), concat and treat them as one.
+                    if previous_line:
+                        line = previous_line.strip() + " " + line.strip() + "\n"
+                        previous_line = ""
+
+                    # Skip parsing if line has a space in front = heuristic to
+                    # skip function argument lines (highly subject to formatting
+                    # changes)
+                    if line[0] == " ":
+                        continue
+
+                    identifier = identifier_regex.search(line)
+
+                    if not identifier:
+                        continue
+
+                    # Find the group that matched, and append it
+                    for group in identifier.groups():
+                        if not group:
+                            continue
+
+                        identifiers.append(Match(
+                            header_file,
+                            line,
+                            line_no,
+                            identifier.span(),
+                            group))
+
+        return identifiers
+
+    def parse_symbols(self):
+        """
+        Compile the Mbed TLS libraries, and parse the TLS, Crypto, and x509
+        object files using nm to retrieve the list of referenced symbols.
+        Exceptions thrown here are rethrown because they would be critical
+        errors that void several tests, and thus needs to halt the program. This
+        is explicitly done for clarity.
+
+        Returns a List of unique symbols defined and used in the libraries.
+        """
+        self.log.info("Compiling...")
+        symbols = []
+
+        # Back up the config and atomically compile with the full configratuion.
+        shutil.copy(
+            "include/mbedtls/mbedtls_config.h",
+            "include/mbedtls/mbedtls_config.h.bak"
+        )
+        try:
+            # Use check=True in all subprocess calls so that failures are raised
+            # as exceptions and logged.
+            subprocess.run(
+                ["python3", "scripts/config.py", "full"],
+                universal_newlines=True,
+                check=True
+            )
+            my_environment = os.environ.copy()
+            my_environment["CFLAGS"] = "-fno-asynchronous-unwind-tables"
+            # Run make clean separately to lib to prevent unwanted behavior when
+            # make is invoked with parallelism.
+            subprocess.run(
+                ["make", "clean"],
+                universal_newlines=True,
+                check=True
+            )
+            subprocess.run(
+                ["make", "lib"],
+                env=my_environment,
+                universal_newlines=True,
+                stdout=subprocess.PIPE,
+                stderr=subprocess.STDOUT,
+                check=True
+            )
+
+            # Perform object file analysis using nm
+            symbols = self.parse_symbols_from_nm([
+                "library/libmbedcrypto.a",
+                "library/libmbedtls.a",
+                "library/libmbedx509.a"
+            ])
+
+            subprocess.run(
+                ["make", "clean"],
+                universal_newlines=True,
+                check=True
+            )
+        except subprocess.CalledProcessError as error:
+            self.log.debug(error.output)
+            raise error
+        finally:
+            # Put back the original config regardless of there being errors.
+            # Works also for keyboard interrupts.
+            shutil.move(
+                "include/mbedtls/mbedtls_config.h.bak",
+                "include/mbedtls/mbedtls_config.h"
+            )
+
+        return symbols
+
+    def parse_symbols_from_nm(self, object_files):
+        """
+        Run nm to retrieve the list of referenced symbols in each object file.
+        Does not return the position data since it is of no use.
+
+        Args:
+        * object_files: a List of compiled object filepaths to search through.
+
+        Returns a List of unique symbols defined and used in any of the object
+        files.
+        """
+        nm_undefined_regex = re.compile(r"^\S+: +U |^$|^\S+:$")
+        nm_valid_regex = re.compile(r"^\S+( [0-9A-Fa-f]+)* . _*(?P<symbol>\w+)")
+        exclusions = ("FStar", "Hacl")
+
+        symbols = []
+
+        # Gather all outputs of nm
+        nm_output = ""
+        for lib in object_files:
+            nm_output += subprocess.run(
+                ["nm", "-og", lib],
+                universal_newlines=True,
+                stdout=subprocess.PIPE,
+                stderr=subprocess.STDOUT,
+                check=True
+            ).stdout
+
+        for line in nm_output.splitlines():
+            if not nm_undefined_regex.search(line):
+                symbol = nm_valid_regex.search(line)
+                if (symbol and not symbol.group("symbol").startswith(exclusions)):
+                    symbols.append(symbol.group("symbol"))
+                else:
+                    self.log.error(line)
+
+        return symbols
+
+class NameChecker():
+    """
+    Representation of the core name checking operation performed by this script.
+    """
+    def __init__(self, parse_result, log):
+        self.parse_result = parse_result
+        self.log = log
+
+    def perform_checks(self, quiet=False):
+        """
+        A comprehensive checker that performs each check in order, and outputs
+        a final verdict.
+
+        Args:
+        * quiet: whether to hide detailed problem explanation.
+        """
+        self.log.info("=============")
+        Problem.quiet = quiet
+        problems = 0
+        problems += self.check_symbols_declared_in_header()
+
+        pattern_checks = [
+            ("macros", MACRO_PATTERN),
+            ("enum_consts", CONSTANTS_PATTERN),
+            ("identifiers", IDENTIFIER_PATTERN)
+        ]
+        for group, check_pattern in pattern_checks:
+            problems += self.check_match_pattern(group, check_pattern)
+
+        problems += self.check_for_typos()
+
+        self.log.info("=============")
+        if problems > 0:
+            self.log.info("FAIL: {0} problem(s) to fix".format(str(problems)))
+            if quiet:
+                self.log.info("Remove --quiet to see explanations.")
+            else:
+                self.log.info("Use --quiet for minimal output.")
+            return 1
+        else:
+            self.log.info("PASS")
+            return 0
+
+    def check_symbols_declared_in_header(self):
+        """
+        Perform a check that all detected symbols in the library object files
+        are properly declared in headers.
+        Assumes parse_names_in_source() was called before this.
+
+        Returns the number of problems that need fixing.
+        """
+        problems = []
+
+        for symbol in self.parse_result["symbols"]:
+            found_symbol_declared = False
+            for identifier_match in self.parse_result["identifiers"]:
+                if symbol == identifier_match.name:
+                    found_symbol_declared = True
+                    break
+
+            if not found_symbol_declared:
+                problems.append(SymbolNotInHeader(symbol))
+
+        self.output_check_result("All symbols in header", problems)
+        return len(problems)
+
+    def check_match_pattern(self, group_to_check, check_pattern):
+        """
+        Perform a check that all items of a group conform to a regex pattern.
+        Assumes parse_names_in_source() was called before this.
+
+        Args:
+        * group_to_check: string key to index into self.parse_result.
+        * check_pattern: the regex to check against.
+
+        Returns the number of problems that need fixing.
+        """
+        problems = []
+
+        for item_match in self.parse_result[group_to_check]:
+            if not re.search(check_pattern, item_match.name):
+                problems.append(PatternMismatch(check_pattern, item_match))
+            # Double underscore should not be used for names
+            if re.search(r".*__.*", item_match.name):
+                problems.append(
+                    PatternMismatch("no double underscore allowed", item_match))
+
+        self.output_check_result(
+            "Naming patterns of {}".format(group_to_check),
+            problems)
+        return len(problems)
+
+    def check_for_typos(self):
+        """
+        Perform a check that all words in the soure code beginning with MBED are
+        either defined as macros, or as enum constants.
+        Assumes parse_names_in_source() was called before this.
+
+        Returns the number of problems that need fixing.
+        """
+        problems = []
+
+        # Set comprehension, equivalent to a list comprehension wrapped by set()
+        all_caps_names = {
+            match.name
+            for match
+            in self.parse_result["macros"] + self.parse_result["enum_consts"]}
+        typo_exclusion = re.compile(r"XXX|__|_$|^MBEDTLS_.*CONFIG_FILE$")
+
+        for name_match in self.parse_result["mbed_words"]:
+            found = name_match.name in all_caps_names
+
+            # Since MBEDTLS_PSA_ACCEL_XXX defines are defined by the
+            # PSA driver, they will not exist as macros. However, they
+            # should still be checked for typos using the equivalent
+            # BUILTINs that exist.
+            if "MBEDTLS_PSA_ACCEL_" in name_match.name:
+                found = name_match.name.replace(
+                    "MBEDTLS_PSA_ACCEL_",
+                    "MBEDTLS_PSA_BUILTIN_") in all_caps_names
+
+            if not found and not typo_exclusion.search(name_match.name):
+                problems.append(Typo(name_match))
+
+        self.output_check_result("Likely typos", problems)
+        return len(problems)
+
+    def output_check_result(self, name, problems):
+        """
+        Write out the PASS/FAIL status of a performed check depending on whether
+        there were problems.
+
+        Args:
+        * name: the name of the test
+        * problems: a List of encountered Problems
+        """
+        if problems:
+            self.log.info("{}: FAIL\n".format(name))
+            for problem in problems:
+                self.log.warning(str(problem))
+        else:
+            self.log.info("{}: PASS".format(name))
+
+def main():
+    """
+    Perform argument parsing, and create an instance of CodeParser and
+    NameChecker to begin the core operation.
+    """
+    parser = argparse.ArgumentParser(
+        formatter_class=argparse.RawDescriptionHelpFormatter,
+        description=(
+            "This script confirms that the naming of all symbols and identifiers "
+            "in Mbed TLS are consistent with the house style and are also "
+            "self-consistent.\n\n"
+            "Expected to be run from the MbedTLS root directory.")
+    )
+    parser.add_argument(
+        "-v", "--verbose",
+        action="store_true",
+        help="show parse results"
+    )
+    parser.add_argument(
+        "-q", "--quiet",
+        action="store_true",
+        help="hide unnecessary text, explanations, and highlighs"
+    )
+
+    args = parser.parse_args()
+
+    # Configure the global logger, which is then passed to the classes below
+    log = logging.getLogger()
+    log.setLevel(logging.DEBUG if args.verbose else logging.INFO)
+    log.addHandler(logging.StreamHandler())
+
+    try:
+        code_parser = CodeParser(log)
+        parse_result = code_parser.comprehensive_parse()
+    except Exception: # pylint: disable=broad-except
+        traceback.print_exc()
+        sys.exit(2)
+
+    name_checker = NameChecker(parse_result, log)
+    return_code = name_checker.perform_checks(quiet=args.quiet)
+
+    sys.exit(return_code)
+
+if __name__ == "__main__":
+    main()
diff --git a/tests/scripts/list-identifiers.sh b/tests/scripts/list-identifiers.sh
index a1c3d2d..9b93080 100755
--- a/tests/scripts/list-identifiers.sh
+++ b/tests/scripts/list-identifiers.sh
@@ -1,8 +1,11 @@
 #!/bin/bash
 #
 # Create a file named identifiers containing identifiers from internal header
-# files or all header files, based on --internal flag.
+# files, based on the --internal flag.
 # Outputs the line count of the file to stdout.
+# A very thin wrapper around list_internal_identifiers.py for backwards
+# compatibility.
+# Must be run from Mbed TLS root.
 #
 # Usage: list-identifiers.sh [ -i | --internal ]
 #
@@ -24,7 +27,7 @@
 set -eu
 
 if [ -d include/mbedtls ]; then :; else
-    echo "$0: must be run from root" >&2
+    echo "$0: Must be run from Mbed TLS root" >&2
     exit 1
 fi
 
@@ -47,32 +50,17 @@
 
 if [ $INTERNAL ]
 then
-    HEADERS=$( ls include/mbedtls/*_internal.h library/*.h | egrep -v 'compat-1\.3\.h|bn_mul' )
+    tests/scripts/list_internal_identifiers.py
+    wc -l identifiers
 else
-    HEADERS=$( ls include/mbedtls/*.h include/psa/*.h library/*.h | egrep -v 'compat-1\.3\.h|bn_mul' )
-    HEADERS="$HEADERS 3rdparty/everest/include/everest/everest.h 3rdparty/everest/include/everest/x25519.h"
+    cat <<EOF
+Sorry, this script has to be called with --internal.
+
+This script exists solely for backwards compatibility with the previous
+iteration of list-identifiers.sh, of which only the --internal option remains in
+use. It is a thin wrapper around list_internal_identifiers.py.
+
+check-names.sh, which used to depend on this script, has been replaced with
+check_names.py and is now self-complete.
+EOF
 fi
-
-rm -f identifiers
-
-grep '^[^ /#{]' $HEADERS | \
-    sed -e 's/^[^:]*://' | \
-    egrep -v '^(extern "C"|(typedef )?(struct|union|enum)( {)?$|};?$)' \
-    > _decls
-
-if true; then
-sed -n -e 's/.* \**\([a-zA-Z_][a-zA-Z0-9_]*\)(.*/\1/p' \
-       -e 's/.*(\*\(.*\))(.*/\1/p' _decls
-grep -v '(' _decls | sed -e 's/\([a-zA-Z0-9_]*\)[;[].*/\1/' -e 's/.* \**//'
-fi > _identifiers
-
-if [ $( wc -l < _identifiers ) -eq $( wc -l < _decls ) ]; then
-    rm _decls
-    egrep -v '^(u?int(16|32|64)_t)$' _identifiers | sort > identifiers
-    rm _identifiers
-else
-    echo "$0: oops, lost some identifiers" 2>&1
-    exit 1
-fi
-
-wc -l identifiers
diff --git a/tests/scripts/list_internal_identifiers.py b/tests/scripts/list_internal_identifiers.py
new file mode 100755
index 0000000..779a16f
--- /dev/null
+++ b/tests/scripts/list_internal_identifiers.py
@@ -0,0 +1,57 @@
+#!/usr/bin/env python3
+#
+# Copyright The Mbed TLS Contributors
+# SPDX-License-Identifier: Apache-2.0
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""
+This script generates a file called identifiers that contains all Mbed TLS
+identifiers found on internal headers. This is the equivalent of what was
+previously `list-identifiers.sh --internal`, and is useful for generating an
+exclusion file list for ABI/API checking, since we do not promise compatibility
+for them.
+
+It uses the CodeParser class from check_names.py to perform the parsing.
+
+The script returns 0 on success, 1 if there is a script error.
+Must be run from Mbed TLS root.
+"""
+
+import argparse
+import logging
+from check_names import CodeParser
+
+def main():
+    parser = argparse.ArgumentParser(
+        formatter_class=argparse.RawDescriptionHelpFormatter,
+        description=(
+            "This script writes a list of parsed identifiers in internal "
+            "headers to \"identifiers\". This is useful for generating a list "
+            "of names to exclude from API/ABI compatibility checking. "))
+
+    parser.parse_args()
+
+    name_check = CodeParser(logging.getLogger())
+    result = name_check.parse_identifiers([
+        "include/mbedtls/*_internal.h",
+        "library/*.h"
+    ])
+    result.sort(key=lambda x: x.name)
+
+    identifiers = ["{}\n".format(match.name) for match in result]
+    with open("identifiers", "w", encoding="utf-8") as f:
+        f.writelines(identifiers)
+
+if __name__ == "__main__":
+    main()