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1#!/usr/bin/env python3
2
3# Copyright The Mbed TLS Contributors
4# SPDX-License-Identifier: Apache-2.0
5#
6# Licensed under the Apache License, Version 2.0 (the "License"); you may
7# not use this file except in compliance with the License.
8# You may obtain a copy of the License at
9#
10# http://www.apache.org/licenses/LICENSE-2.0
11#
12# Unless required by applicable law or agreed to in writing, software
13# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
14# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15# See the License for the specific language governing permissions and
16# limitations under the License.
17
18"""
19This script checks the current state of the source code for minor issues,
20including incorrect file permissions, presence of tabs, non-Unix line endings,
21trailing whitespace, and presence of UTF-8 BOM.
22Note: requires python 3, must be run from Mbed TLS root.
23"""
24
25import os
26import argparse
27import logging
28import codecs
29import re
30import subprocess
31import sys
32try:
33    from typing import FrozenSet, Optional, Pattern # pylint: disable=unused-import
34except ImportError:
35    pass
36
37import scripts_path # pylint: disable=unused-import
38from mbedtls_dev import build_tree
39
40
41class FileIssueTracker:
42    """Base class for file-wide issue tracking.
43
44    To implement a checker that processes a file as a whole, inherit from
45    this class and implement `check_file_for_issue` and define ``heading``.
46
47    ``suffix_exemptions``: files whose name ends with a string in this set
48     will not be checked.
49
50    ``path_exemptions``: files whose path (relative to the root of the source
51    tree) matches this regular expression will not be checked. This can be
52    ``None`` to match no path. Paths are normalized and converted to ``/``
53    separators before matching.
54
55    ``heading``: human-readable description of the issue
56    """
57
58    suffix_exemptions = frozenset() #type: FrozenSet[str]
59    path_exemptions = None #type: Optional[Pattern[str]]
60    # heading must be defined in derived classes.
61    # pylint: disable=no-member
62
63    def __init__(self):
64        self.files_with_issues = {}
65
66    @staticmethod
67    def normalize_path(filepath):
68        """Normalize ``filepath`` with / as the directory separator."""
69        filepath = os.path.normpath(filepath)
70        # On Windows, we may have backslashes to separate directories.
71        # We need slashes to match exemption lists.
72        seps = os.path.sep
73        if os.path.altsep is not None:
74            seps += os.path.altsep
75        return '/'.join(filepath.split(seps))
76
77    def should_check_file(self, filepath):
78        """Whether the given file name should be checked.
79
80        Files whose name ends with a string listed in ``self.suffix_exemptions``
81        or whose path matches ``self.path_exemptions`` will not be checked.
82        """
83        for files_exemption in self.suffix_exemptions:
84            if filepath.endswith(files_exemption):
85                return False
86        if self.path_exemptions and \
87           re.match(self.path_exemptions, self.normalize_path(filepath)):
88            return False
89        return True
90
91    def check_file_for_issue(self, filepath):
92        """Check the specified file for the issue that this class is for.
93
94        Subclasses must implement this method.
95        """
96        raise NotImplementedError
97
98    def record_issue(self, filepath, line_number):
99        """Record that an issue was found at the specified location."""
100        if filepath not in self.files_with_issues.keys():
101            self.files_with_issues[filepath] = []
102        self.files_with_issues[filepath].append(line_number)
103
104    def output_file_issues(self, logger):
105        """Log all the locations where the issue was found."""
106        if self.files_with_issues.values():
107            logger.info(self.heading)
108            for filename, lines in sorted(self.files_with_issues.items()):
109                if lines:
110                    logger.info("{}: {}".format(
111                        filename, ", ".join(str(x) for x in lines)
112                    ))
113                else:
114                    logger.info(filename)
115            logger.info("")
116
117BINARY_FILE_PATH_RE_LIST = [
118    r'docs/.*\.pdf\Z',
119    r'programs/fuzz/corpuses/[^.]+\Z',
120    r'tests/data_files/[^.]+\Z',
121    r'tests/data_files/.*\.(crt|csr|db|der|key|pubkey)\Z',
122    r'tests/data_files/.*\.req\.[^/]+\Z',
123    r'tests/data_files/.*malformed[^/]+\Z',
124    r'tests/data_files/format_pkcs12\.fmt\Z',
125    r'tests/data_files/.*\.bin\Z',
126]
127BINARY_FILE_PATH_RE = re.compile('|'.join(BINARY_FILE_PATH_RE_LIST))
128
129class LineIssueTracker(FileIssueTracker):
130    """Base class for line-by-line issue tracking.
131
132    To implement a checker that processes files line by line, inherit from
133    this class and implement `line_with_issue`.
134    """
135
136    # Exclude binary files.
137    path_exemptions = BINARY_FILE_PATH_RE
138
139    def issue_with_line(self, line, filepath, line_number):
140        """Check the specified line for the issue that this class is for.
141
142        Subclasses must implement this method.
143        """
144        raise NotImplementedError
145
146    def check_file_line(self, filepath, line, line_number):
147        if self.issue_with_line(line, filepath, line_number):
148            self.record_issue(filepath, line_number)
149
150    def check_file_for_issue(self, filepath):
151        """Check the lines of the specified file.
152
153        Subclasses must implement the ``issue_with_line`` method.
154        """
155        with open(filepath, "rb") as f:
156            for i, line in enumerate(iter(f.readline, b"")):
157                self.check_file_line(filepath, line, i + 1)
158
159
160def is_windows_file(filepath):
161    _root, ext = os.path.splitext(filepath)
162    return ext in ('.bat', '.dsp', '.dsw', '.sln', '.vcxproj')
163
164
165class PermissionIssueTracker(FileIssueTracker):
166    """Track files with bad permissions.
167
168    Files that are not executable scripts must not be executable."""
169
170    heading = "Incorrect permissions:"
171
172    # .py files can be either full scripts or modules, so they may or may
173    # not be executable.
174    suffix_exemptions = frozenset({".py"})
175
176    def check_file_for_issue(self, filepath):
177        is_executable = os.access(filepath, os.X_OK)
178        should_be_executable = filepath.endswith((".sh", ".pl"))
179        if is_executable != should_be_executable:
180            self.files_with_issues[filepath] = None
181
182
183class ShebangIssueTracker(FileIssueTracker):
184    """Track files with a bad, missing or extraneous shebang line.
185
186    Executable scripts must start with a valid shebang (#!) line.
187    """
188
189    heading = "Invalid shebang line:"
190
191    # Allow either /bin/sh, /bin/bash, or /usr/bin/env.
192    # Allow at most one argument (this is a Linux limitation).
193    # For sh and bash, the argument if present must be options.
194    # For env, the argument must be the base name of the interpreter.
195    _shebang_re = re.compile(rb'^#! ?(?:/bin/(bash|sh)(?: -[^\n ]*)?'
196                             rb'|/usr/bin/env ([^\n /]+))$')
197    _extensions = {
198        b'bash': 'sh',
199        b'perl': 'pl',
200        b'python3': 'py',
201        b'sh': 'sh',
202    }
203
204    def is_valid_shebang(self, first_line, filepath):
205        m = re.match(self._shebang_re, first_line)
206        if not m:
207            return False
208        interpreter = m.group(1) or m.group(2)
209        if interpreter not in self._extensions:
210            return False
211        if not filepath.endswith('.' + self._extensions[interpreter]):
212            return False
213        return True
214
215    def check_file_for_issue(self, filepath):
216        is_executable = os.access(filepath, os.X_OK)
217        with open(filepath, "rb") as f:
218            first_line = f.readline()
219        if first_line.startswith(b'#!'):
220            if not is_executable:
221                # Shebang on a non-executable file
222                self.files_with_issues[filepath] = None
223            elif not self.is_valid_shebang(first_line, filepath):
224                self.files_with_issues[filepath] = [1]
225        elif is_executable:
226            # Executable without a shebang
227            self.files_with_issues[filepath] = None
228
229
230class EndOfFileNewlineIssueTracker(FileIssueTracker):
231    """Track files that end with an incomplete line
232    (no newline character at the end of the last line)."""
233
234    heading = "Missing newline at end of file:"
235
236    path_exemptions = BINARY_FILE_PATH_RE
237
238    def check_file_for_issue(self, filepath):
239        with open(filepath, "rb") as f:
240            try:
241                f.seek(-1, 2)
242            except OSError:
243                # This script only works on regular files. If we can't seek
244                # 1 before the end, it means that this position is before
245                # the beginning of the file, i.e. that the file is empty.
246                return
247            if f.read(1) != b"\n":
248                self.files_with_issues[filepath] = None
249
250
251class Utf8BomIssueTracker(FileIssueTracker):
252    """Track files that start with a UTF-8 BOM.
253    Files should be ASCII or UTF-8. Valid UTF-8 does not start with a BOM."""
254
255    heading = "UTF-8 BOM present:"
256
257    suffix_exemptions = frozenset([".vcxproj", ".sln"])
258    path_exemptions = BINARY_FILE_PATH_RE
259
260    def check_file_for_issue(self, filepath):
261        with open(filepath, "rb") as f:
262            if f.read().startswith(codecs.BOM_UTF8):
263                self.files_with_issues[filepath] = None
264
265
266class UnicodeIssueTracker(LineIssueTracker):
267    """Track lines with invalid characters or invalid text encoding."""
268
269    heading = "Invalid UTF-8 or forbidden character:"
270
271    # Only allow valid UTF-8, and only other explicitly allowed characters.
272    # We deliberately exclude all characters that aren't a simple non-blank,
273    # non-zero-width glyph, apart from a very small set (tab, ordinary space,
274    # line breaks, "basic" no-break space and soft hyphen). In particular,
275    # non-ASCII control characters, combinig characters, and Unicode state
276    # changes (e.g. right-to-left text) are forbidden.
277    # Note that we do allow some characters with a risk of visual confusion,
278    # for example '-' (U+002D HYPHEN-MINUS) vs '­' (U+00AD SOFT HYPHEN) vs
279    # '‐' (U+2010 HYPHEN), or 'A' (U+0041 LATIN CAPITAL LETTER A) vs
280    # 'Α' (U+0391 GREEK CAPITAL LETTER ALPHA).
281    GOOD_CHARACTERS = ''.join([
282        '\t\n\r -~', # ASCII (tabs and line endings are checked separately)
283        '\u00A0-\u00FF', # Latin-1 Supplement (for NO-BREAK SPACE and punctuation)
284        '\u2010-\u2027\u2030-\u205E', # General Punctuation (printable)
285        '\u2070\u2071\u2074-\u208E\u2090-\u209C', # Superscripts and Subscripts
286        '\u2190-\u21FF', # Arrows
287        '\u2200-\u22FF', # Mathematical Symbols
288        '\u2500-\u257F' # Box Drawings characters used in markdown trees
289    ])
290    # Allow any of the characters and ranges above, and anything classified
291    # as a word constituent.
292    GOOD_CHARACTERS_RE = re.compile(r'[\w{}]+\Z'.format(GOOD_CHARACTERS))
293
294    def issue_with_line(self, line, _filepath, line_number):
295        try:
296            text = line.decode('utf-8')
297        except UnicodeDecodeError:
298            return True
299        if line_number == 1 and text.startswith('\uFEFF'):
300            # Strip BOM (U+FEFF ZERO WIDTH NO-BREAK SPACE) at the beginning.
301            # Which files are allowed to have a BOM is handled in
302            # Utf8BomIssueTracker.
303            text = text[1:]
304        return not self.GOOD_CHARACTERS_RE.match(text)
305
306class UnixLineEndingIssueTracker(LineIssueTracker):
307    """Track files with non-Unix line endings (i.e. files with CR)."""
308
309    heading = "Non-Unix line endings:"
310
311    def should_check_file(self, filepath):
312        if not super().should_check_file(filepath):
313            return False
314        return not is_windows_file(filepath)
315
316    def issue_with_line(self, line, _filepath, _line_number):
317        return b"\r" in line
318
319
320class WindowsLineEndingIssueTracker(LineIssueTracker):
321    """Track files with non-Windows line endings (i.e. CR or LF not in CRLF)."""
322
323    heading = "Non-Windows line endings:"
324
325    def should_check_file(self, filepath):
326        if not super().should_check_file(filepath):
327            return False
328        return is_windows_file(filepath)
329
330    def issue_with_line(self, line, _filepath, _line_number):
331        return not line.endswith(b"\r\n") or b"\r" in line[:-2]
332
333
334class TrailingWhitespaceIssueTracker(LineIssueTracker):
335    """Track lines with trailing whitespace."""
336
337    heading = "Trailing whitespace:"
338    suffix_exemptions = frozenset([".dsp", ".md"])
339
340    def issue_with_line(self, line, _filepath, _line_number):
341        return line.rstrip(b"\r\n") != line.rstrip()
342
343
344class TabIssueTracker(LineIssueTracker):
345    """Track lines with tabs."""
346
347    heading = "Tabs present:"
348    suffix_exemptions = frozenset([
349        ".pem", # some openssl dumps have tabs
350        ".sln",
351        "/Makefile",
352        "/Makefile.inc",
353        "/generate_visualc_files.pl",
354    ])
355
356    def issue_with_line(self, line, _filepath, _line_number):
357        return b"\t" in line
358
359
360class MergeArtifactIssueTracker(LineIssueTracker):
361    """Track lines with merge artifacts.
362    These are leftovers from a ``git merge`` that wasn't fully edited."""
363
364    heading = "Merge artifact:"
365
366    def issue_with_line(self, line, _filepath, _line_number):
367        # Detect leftover git conflict markers.
368        if line.startswith(b'<<<<<<< ') or line.startswith(b'>>>>>>> '):
369            return True
370        if line.startswith(b'||||||| '): # from merge.conflictStyle=diff3
371            return True
372        if line.rstrip(b'\r\n') == b'=======' and \
373           not _filepath.endswith('.md'):
374            return True
375        return False
376
377
378class IntegrityChecker:
379    """Sanity-check files under the current directory."""
380
381    def __init__(self, log_file):
382        """Instantiate the sanity checker.
383        Check files under the current directory.
384        Write a report of issues to log_file."""
385        build_tree.check_repo_path()
386        self.logger = None
387        self.setup_logger(log_file)
388        self.issues_to_check = [
389            PermissionIssueTracker(),
390            ShebangIssueTracker(),
391            EndOfFileNewlineIssueTracker(),
392            Utf8BomIssueTracker(),
393            UnicodeIssueTracker(),
394            UnixLineEndingIssueTracker(),
395            WindowsLineEndingIssueTracker(),
396            TrailingWhitespaceIssueTracker(),
397            TabIssueTracker(),
398            MergeArtifactIssueTracker(),
399        ]
400
401    def setup_logger(self, log_file, level=logging.INFO):
402        self.logger = logging.getLogger()
403        self.logger.setLevel(level)
404        if log_file:
405            handler = logging.FileHandler(log_file)
406            self.logger.addHandler(handler)
407        else:
408            console = logging.StreamHandler()
409            self.logger.addHandler(console)
410
411    @staticmethod
412    def collect_files():
413        bytes_output = subprocess.check_output(['git', 'ls-files', '-z'])
414        bytes_filepaths = bytes_output.split(b'\0')[:-1]
415        ascii_filepaths = map(lambda fp: fp.decode('ascii'), bytes_filepaths)
416        # Prepend './' to files in the top-level directory so that
417        # something like `'/Makefile' in fp` matches in the top-level
418        # directory as well as in subdirectories.
419        return [fp if os.path.dirname(fp) else os.path.join(os.curdir, fp)
420                for fp in ascii_filepaths]
421
422    def check_files(self):
423        for issue_to_check in self.issues_to_check:
424            for filepath in self.collect_files():
425                if issue_to_check.should_check_file(filepath):
426                    issue_to_check.check_file_for_issue(filepath)
427
428    def output_issues(self):
429        integrity_return_code = 0
430        for issue_to_check in self.issues_to_check:
431            if issue_to_check.files_with_issues:
432                integrity_return_code = 1
433            issue_to_check.output_file_issues(self.logger)
434        return integrity_return_code
435
436
437def run_main():
438    parser = argparse.ArgumentParser(description=__doc__)
439    parser.add_argument(
440        "-l", "--log_file", type=str, help="path to optional output log",
441    )
442    check_args = parser.parse_args()
443    integrity_check = IntegrityChecker(check_args.log_file)
444    integrity_check.check_files()
445    return_code = integrity_check.output_issues()
446    sys.exit(return_code)
447
448
449if __name__ == "__main__":
450    run_main()
451