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#! /usr/bin/python3.9 # NOTE: the above "/usr/local/bin/python" is NOT a mistake.  It is# intentionally NOT "/usr/bin/env python".  On many systems# (e.g. Solaris), /usr/local/bin is not in $PATH as passed to CGI# scripts, and /usr/local/bin is the default directory where Python is# installed, so /usr/bin/env would be unable to find python.  Granted,# binary installations by Linux vendors often install Python in# /usr/bin.  So let those vendors patch cgi.py to match their choice# of installation. """Support module for CGI (Common Gateway Interface) scripts. This module defines a number of utilities for use by CGI scriptswritten in Python.""" # History# -------## Michael McLay started this module.  Steve Majewski changed the# interface to SvFormContentDict and FormContentDict.  The multipart# parsing was inspired by code submitted by Andreas Paepcke.  Guido van# Rossum rewrote, reformatted and documented the module and is currently# responsible for its maintenance.# __version__ = "2.6"  # Imports# ======= from io import StringIO, BytesIO, TextIOWrapperfrom collections.abc import Mappingimport sysimport osimport urllib.parsefrom email.parser import FeedParserfrom email.message import Messageimport htmlimport localeimport tempfile __all__ = ["MiniFieldStorage", "FieldStorage", "parse", "parse_multipart",           "parse_header", "test", "print_exception", "print_environ",           "print_form", "print_directory", "print_arguments",           "print_environ_usage"] # Logging support# =============== logfile = ""            # Filename to log to, if not emptylogfp = None            # File object to log to, if not None def initlog(*allargs):    """Write a log message, if there is a log file.     Even though this function is called initlog(), you should always    use log(); log is a variable that is set either to initlog    (initially), to dolog (once the log file has been opened), or to    nolog (when logging is disabled).     The first argument is a format string; the remaining arguments (if    any) are arguments to the % operator, so e.g.        log("%s: %s", "a", "b")    will write "a: b" to the log file, followed by a newline.     If the global logfp is not None, it should be a file object to    which log data is written.     If the global logfp is None, the global logfile may be a string    giving a filename to open, in append mode.  This file should be    world writable!!!  If the file can't be opened, logging is    silently disabled (since there is no safe place where we could    send an error message).     """    global log, logfile, logfp    if logfile and not logfp:        try:            logfp = open(logfile, "a")        except OSError:            pass    if not logfp:        log = nolog    else:        log = dolog    log(*allargs) def dolog(fmt, *args):    """Write a log message to the log file.  See initlog() for docs."""    logfp.write(fmt%args + "\n") def nolog(*allargs):    """Dummy function, assigned to log when logging is disabled."""    pass def closelog():    """Close the log file."""    global log, logfile, logfp    logfile = ''    if logfp:        logfp.close()        logfp = None    log = initlog log = initlog           # The current logging function  # Parsing functions# ================= # Maximum input we will accept when REQUEST_METHOD is POST# 0 ==> unlimited inputmaxlen = 0 def parse(fp=None, environ=os.environ, keep_blank_values=0,          strict_parsing=0, separator='&'):    """Parse a query in the environment or from a file (default stdin)         Arguments, all optional:         fp              : file pointer; default: sys.stdin.buffer         environ         : environment dictionary; default: os.environ         keep_blank_values: flag indicating whether blank values in            percent-encoded forms should be treated as blank strings.            A true value indicates that blanks should be retained as            blank strings.  The default false value indicates that            blank values are to be ignored and treated as if they were            not included.         strict_parsing: flag indicating what to do with parsing errors.            If false (the default), errors are silently ignored.            If true, errors raise a ValueError exception.         separator: str. The symbol to use for separating the query arguments.            Defaults to &.    """    if fp is None:        fp = sys.stdin     # field keys and values (except for files) are returned as strings    # an encoding is required to decode the bytes read from self.fp    if hasattr(fp,'encoding'):        encoding = fp.encoding    else:        encoding = 'latin-1'     # fp.read() must return bytes    if isinstance(fp, TextIOWrapper):        fp = fp.buffer     if not 'REQUEST_METHOD' in environ:        environ['REQUEST_METHOD'] = 'GET'       # For testing stand-alone    if environ['REQUEST_METHOD'] == 'POST':        ctype, pdict = parse_header(environ['CONTENT_TYPE'])        if ctype == 'multipart/form-data':            return parse_multipart(fp, pdict, separator=separator)        elif ctype == 'application/x-www-form-urlencoded':            clength = int(environ['CONTENT_LENGTH'])            if maxlen and clength > maxlen:                raise ValueError('Maximum content length exceeded')            qs = fp.read(clength).decode(encoding)        else:            qs = ''                     # Unknown content-type        if 'QUERY_STRING' in environ:            if qs: qs = qs + '&'            qs = qs + environ['QUERY_STRING']        elif sys.argv[1:]:            if qs: qs = qs + '&'            qs = qs + sys.argv[1]        environ['QUERY_STRING'] = qs    # XXX Shouldn't, really    elif 'QUERY_STRING' in environ:        qs = environ['QUERY_STRING']    else:        if sys.argv[1:]:            qs = sys.argv[1]        else:            qs = ""        environ['QUERY_STRING'] = qs    # XXX Shouldn't, really    return urllib.parse.parse_qs(qs, keep_blank_values, strict_parsing,                                 encoding=encoding, separator=separator)  def parse_multipart(fp, pdict, encoding="utf-8", errors="replace", separator='&'):    """Parse multipart input.     Arguments:    fp   : input file    pdict: dictionary containing other parameters of content-type header    encoding, errors: request encoding and error handler, passed to        FieldStorage     Returns a dictionary just like parse_qs(): keys are the field names, each    value is a list of values for that field. For non-file fields, the value    is a list of strings.    """    # RFC 2026, Section 5.1 : The "multipart" boundary delimiters are always    # represented as 7bit US-ASCII.    boundary = pdict['boundary'].decode('ascii')    ctype = "multipart/form-data; boundary={}".format(boundary)    headers = Message()    headers.set_type(ctype)    try:        headers['Content-Length'] = pdict['CONTENT-LENGTH']    except KeyError:        pass    fs = FieldStorage(fp, headers=headers, encoding=encoding, errors=errors,        environ={'REQUEST_METHOD': 'POST'}, separator=separator)    return {k: fs.getlist(k) for k in fs} def _parseparam(s):    while s[:1] == ';':        s = s[1:]        end = s.find(';')        while end > 0 and (s.count('"', 0, end) - s.count('\\"', 0, end)) % 2:            end = s.find(';', end + 1)        if end < 0:            end = len(s)        f = s[:end]        yield f.strip()        s = s[end:] def parse_header(line):    """Parse a Content-type like header.     Return the main content-type and a dictionary of options.     """    parts = _parseparam(';' + line)    key = parts.__next__()    pdict = {}    for p in parts:        i = p.find('=')        if i >= 0:            name = p[:i].strip().lower()            value = p[i+1:].strip()            if len(value) >= 2 and value[0] == value[-1] == '"':                value = value[1:-1]                value = value.replace('\\\\', '\\').replace('\\"', '"')            pdict[name] = value    return key, pdict  # Classes for field storage# ========================= class MiniFieldStorage:     """Like FieldStorage, for use when no file uploads are possible."""     # Dummy attributes    filename = None    list = None    type = None    file = None    type_options = {}    disposition = None    disposition_options = {}    headers = {}     def __init__(self, name, value):        """Constructor from field name and value."""        self.name = name        self.value = value        # self.file = StringIO(value)     def __repr__(self):        """Return printable representation."""        return "MiniFieldStorage(%r, %r)" % (self.name, self.value)  class FieldStorage:     """Store a sequence of fields, reading multipart/form-data.     This class provides naming, typing, files stored on disk, and    more.  At the top level, it is accessible like a dictionary, whose    keys are the field names.  (Note: None can occur as a field name.)    The items are either a Python list (if there's multiple values) or    another FieldStorage or MiniFieldStorage object.  If it's a single    object, it has the following attributes:     name: the field name, if specified; otherwise None     filename: the filename, if specified; otherwise None; this is the        client side filename, *not* the file name on which it is        stored (that's a temporary file you don't deal with)     value: the value as a *string*; for file uploads, this        transparently reads the file every time you request the value        and returns *bytes*     file: the file(-like) object from which you can read the data *as        bytes* ; None if the data is stored a simple string     type: the content-type, or None if not specified     type_options: dictionary of options specified on the content-type        line     disposition: content-disposition, or None if not specified     disposition_options: dictionary of corresponding options     headers: a dictionary(-like) object (sometimes email.message.Message or a        subclass thereof) containing *all* headers     The class is subclassable, mostly for the purpose of overriding    the make_file() method, which is called internally to come up with    a file open for reading and writing.  This makes it possible to    override the default choice of storing all files in a temporary    directory and unlinking them as soon as they have been opened.     """    def __init__(self, fp=None, headers=None, outerboundary=b'',                 environ=os.environ, keep_blank_values=0, strict_parsing=0,                 limit=None, encoding='utf-8', errors='replace',                 max_num_fields=None, separator='&'):        """Constructor.  Read multipart/* until last part.         Arguments, all optional:         fp              : file pointer; default: sys.stdin.buffer            (not used when the request method is GET)            Can be :            1. a TextIOWrapper object            2. an object whose read() and readline() methods return bytes         headers         : header dictionary-like object; default:            taken from environ as per CGI spec         outerboundary   : terminating multipart boundary            (for internal use only)         environ         : environment dictionary; default: os.environ         keep_blank_values: flag indicating whether blank values in            percent-encoded forms should be treated as blank strings.            A true value indicates that blanks should be retained as            blank strings.  The default false value indicates that            blank values are to be ignored and treated as if they were            not included.         strict_parsing: flag indicating what to do with parsing errors.            If false (the default), errors are silently ignored.            If true, errors raise a ValueError exception.         limit : used internally to read parts of multipart/form-data forms,            to exit from the reading loop when reached. It is the difference            between the form content-length and the number of bytes already            read         encoding, errors : the encoding and error handler used to decode the            binary stream to strings. Must be the same as the charset defined            for the page sending the form (content-type : meta http-equiv or            header)         max_num_fields: int. If set, then __init__ throws a ValueError            if there are more than n fields read by parse_qsl().         """        method = 'GET'        self.keep_blank_values = keep_blank_values        self.strict_parsing = strict_parsing        self.max_num_fields = max_num_fields        self.separator = separator        if 'REQUEST_METHOD' in environ:            method = environ['REQUEST_METHOD'].upper()        self.qs_on_post = None        if method == 'GET' or method == 'HEAD':            if 'QUERY_STRING' in environ:                qs = environ['QUERY_STRING']            elif sys.argv[1:]:                qs = sys.argv[1]            else:                qs = ""            qs = qs.encode(locale.getpreferredencoding(), 'surrogateescape')            fp = BytesIO(qs)            if headers is None:                headers = {'content-type':                           "application/x-www-form-urlencoded"}        if headers is None:            headers = {}            if method == 'POST':                # Set default content-type for POST to what's traditional                headers['content-type'] = "application/x-www-form-urlencoded"            if 'CONTENT_TYPE' in environ:                headers['content-type'] = environ['CONTENT_TYPE']            if 'QUERY_STRING' in environ:                self.qs_on_post = environ['QUERY_STRING']            if 'CONTENT_LENGTH' in environ:                headers['content-length'] = environ['CONTENT_LENGTH']        else:            if not (isinstance(headers, (Mapping, Message))):                raise TypeError("headers must be mapping or an instance of "                                "email.message.Message")        self.headers = headers        if fp is None:            self.fp = sys.stdin.buffer        # self.fp.read() must return bytes        elif isinstance(fp, TextIOWrapper):            self.fp = fp.buffer        else:            if not (hasattr(fp, 'read') and hasattr(fp, 'readline')):                raise TypeError("fp must be file pointer")            self.fp = fp         self.encoding = encoding        self.errors = errors         if not isinstance(outerboundary, bytes):            raise TypeError('outerboundary must be bytes, not %s'                            % type(outerboundary).__name__)        self.outerboundary = outerboundary         self.bytes_read = 0        self.limit = limit         # Process content-disposition header        cdisp, pdict = "", {}        if 'content-disposition' in self.headers:            cdisp, pdict = parse_header(self.headers['content-disposition'])        self.disposition = cdisp        self.disposition_options = pdict        self.name = None        if 'name' in pdict:            self.name = pdict['name']        self.filename = None        if 'filename' in pdict:            self.filename = pdict['filename']        self._binary_file = self.filename is not None         # Process content-type header        #        # Honor any existing content-type header.  But if there is no        # content-type header, use some sensible defaults.  Assume        # outerboundary is "" at the outer level, but something non-false        # inside a multi-part.  The default for an inner part is text/plain,        # but for an outer part it should be urlencoded.  This should catch        # bogus clients which erroneously forget to include a content-type        # header.        #        # See below for what we do if there does exist a content-type header,        # but it happens to be something we don't understand.        if 'content-type' in self.headers:            ctype, pdict = parse_header(self.headers['content-type'])        elif self.outerboundary or method != 'POST':            ctype, pdict = "text/plain", {}        else:            ctype, pdict = 'application/x-www-form-urlencoded', {}        self.type = ctype        self.type_options = pdict        if 'boundary' in pdict:            self.innerboundary = pdict['boundary'].encode(self.encoding,                                                          self.errors)        else:            self.innerboundary = b""         clen = -1        if 'content-length' in self.headers:            try:                clen = int(self.headers['content-length'])            except ValueError:                pass            if maxlen and clen > maxlen:                raise ValueError('Maximum content length exceeded')        self.length = clen        if self.limit is None and clen >= 0:            self.limit = clen         self.list = self.file = None        self.done = 0        if ctype == 'application/x-www-form-urlencoded':            self.read_urlencoded()        elif ctype[:10] == 'multipart/':            self.read_multi(environ, keep_blank_values, strict_parsing)        else:            self.read_single()     def __del__(self):        try:            self.file.close()        except AttributeError:            pass     def __enter__(self):        return self     def __exit__(self, *args):        self.file.close()     def __repr__(self):        """Return a printable representation."""        return "FieldStorage(%r, %r, %r)" % (                self.name, self.filename, self.value)     def __iter__(self):        return iter(self.keys())     def __getattr__(self, name):        if name != 'value':            raise AttributeError(name)        if self.file:            self.file.seek(0)            value = self.file.read()            self.file.seek(0)        elif self.list is not None:            value = self.list        else:            value = None        return value     def __getitem__(self, key):        """Dictionary style indexing."""        if self.list is None:            raise TypeError("not indexable")        found = []        for item in self.list:            if item.name == key: found.append(item)        if not found:            raise KeyError(key)        if len(found) == 1:            return found[0]        else:            return found     def getvalue(self, key, default=None):        """Dictionary style get() method, including 'value' lookup."""        if key in self:            value = self[key]            if isinstance(value, list):                return [x.value for x in value]            else:                return value.value        else:            return default     def getfirst(self, key, default=None):        """ Return the first value received."""        if key in self:            value = self[key]            if isinstance(value, list):                return value[0].value            else:                return value.value        else:            return default     def getlist(self, key):        """ Return list of received values."""        if key in self:            value = self[key]            if isinstance(value, list):                return [x.value for x in value]            else:                return [value.value]        else:            return []     def keys(self):        """Dictionary style keys() method."""        if self.list is None:            raise TypeError("not indexable")        return list(set(item.name for item in self.list))     def __contains__(self, key):        """Dictionary style __contains__ method."""        if self.list is None:            raise TypeError("not indexable")        return any(item.name == key for item in self.list)     def __len__(self):        """Dictionary style len(x) support."""        return len(self.keys())     def __bool__(self):        if self.list is None:            raise TypeError("Cannot be converted to bool.")        return bool(self.list)     def read_urlencoded(self):        """Internal: read data in query string format."""        qs = self.fp.read(self.length)        if not isinstance(qs, bytes):            raise ValueError("%s should return bytes, got %s" \                             % (self.fp, type(qs).__name__))        qs = qs.decode(self.encoding, self.errors)        if self.qs_on_post:            qs += '&' + self.qs_on_post        query = urllib.parse.parse_qsl(            qs, self.keep_blank_values, self.strict_parsing,            encoding=self.encoding, errors=self.errors,            max_num_fields=self.max_num_fields, separator=self.separator)        self.list = [MiniFieldStorage(key, value) for key, value in query]        self.skip_lines()     FieldStorageClass = None     def read_multi(self, environ, keep_blank_values, strict_parsing):        """Internal: read a part that is itself multipart."""        ib = self.innerboundary        if not valid_boundary(ib):            raise ValueError('Invalid boundary in multipart form: %r' % (ib,))        self.list = []        if self.qs_on_post:            query = urllib.parse.parse_qsl(                self.qs_on_post, self.keep_blank_values, self.strict_parsing,                encoding=self.encoding, errors=self.errors,                max_num_fields=self.max_num_fields, separator=self.separator)            self.list.extend(MiniFieldStorage(key, value) for key, value in query)         klass = self.FieldStorageClass or self.__class__        first_line = self.fp.readline() # bytes        if not isinstance(first_line, bytes):            raise ValueError("%s should return bytes, got %s" \                             % (self.fp, type(first_line).__name__))        self.bytes_read += len(first_line)         # Ensure that we consume the file until we've hit our inner boundary        while (first_line.strip() != (b"--" + self.innerboundary) and                first_line):            first_line = self.fp.readline()            self.bytes_read += len(first_line)         # Propagate max_num_fields into the sub class appropriately        max_num_fields = self.max_num_fields        if max_num_fields is not None:            max_num_fields -= len(self.list)         while True:            parser = FeedParser()            hdr_text = b""            while True:                data = self.fp.readline()                hdr_text += data                if not data.strip():                    break            if not hdr_text:                break            # parser takes strings, not bytes            self.bytes_read += len(hdr_text)            parser.feed(hdr_text.decode(self.encoding, self.errors))            headers = parser.close()             # Some clients add Content-Length for part headers, ignore them            if 'content-length' in headers:                del headers['content-length']             limit = None if self.limit is None \                else self.limit - self.bytes_read            part = klass(self.fp, headers, ib, environ, keep_blank_values,                         strict_parsing, limit,                         self.encoding, self.errors, max_num_fields, self.separator)             if max_num_fields is not None:                max_num_fields -= 1                if part.list:                    max_num_fields -= len(part.list)                if max_num_fields < 0:                    raise ValueError('Max number of fields exceeded')             self.bytes_read += part.bytes_read            self.list.append(part)            if part.done or self.bytes_read >= self.length > 0:                break        self.skip_lines()     def read_single(self):        """Internal: read an atomic part."""        if self.length >= 0:            self.read_binary()            self.skip_lines()        else:            self.read_lines()        self.file.seek(0)     bufsize = 8*1024            # I/O buffering size for copy to file     def read_binary(self):        """Internal: read binary data."""        self.file = self.make_file()        todo = self.length        if todo >= 0:            while todo > 0:                data = self.fp.read(min(todo, self.bufsize)) # bytes                if not isinstance(data, bytes):                    raise ValueError("%s should return bytes, got %s"                                     % (self.fp, type(data).__name__))                self.bytes_read += len(data)                if not data:                    self.done = -1                    break                self.file.write(data)                todo = todo - len(data)     def read_lines(self):        """Internal: read lines until EOF or outerboundary."""        if self._binary_file:            self.file = self.__file = BytesIO() # store data as bytes for files        else:            self.file = self.__file = StringIO() # as strings for other fields        if self.outerboundary:            self.read_lines_to_outerboundary()        else:            self.read_lines_to_eof()     def __write(self, line):        """line is always bytes, not string"""        if self.__file is not None:            if self.__file.tell() + len(line) > 1000:                self.file = self.make_file()                data = self.__file.getvalue()                self.file.write(data)                self.__file = None        if self._binary_file:            # keep bytes            self.file.write(line)        else:            # decode to string            self.file.write(line.decode(self.encoding, self.errors))     def read_lines_to_eof(self):        """Internal: read lines until EOF."""        while 1:            line = self.fp.readline(1<<16) # bytes            self.bytes_read += len(line)            if not line:                self.done = -1                break            self.__write(line)     def read_lines_to_outerboundary(self):        """Internal: read lines until outerboundary.        Data is read as bytes: boundaries and line ends must be converted        to bytes for comparisons.        """        next_boundary = b"--" + self.outerboundary        last_boundary = next_boundary + b"--"        delim = b""        last_line_lfend = True        _read = 0        while 1:             if self.limit is not None and 0 <= self.limit <= _read:                break            line = self.fp.readline(1<<16) # bytes            self.bytes_read += len(line)            _read += len(line)            if not line:                self.done = -1                break            if delim == b"\r":                line = delim + line                delim = b""            if line.startswith(b"--") and last_line_lfend:                strippedline = line.rstrip()                if strippedline == next_boundary:                    break                if strippedline == last_boundary:                    self.done = 1                    break            odelim = delim            if line.endswith(b"\r\n"):                delim = b"\r\n"                line = line[:-2]                last_line_lfend = True            elif line.endswith(b"\n"):                delim = b"\n"                line = line[:-1]                last_line_lfend = True            elif line.endswith(b"\r"):                # We may interrupt \r\n sequences if they span the 2**16                # byte boundary                delim = b"\r"                line = line[:-1]                last_line_lfend = False            else:                delim = b""                last_line_lfend = False            self.__write(odelim + line)     def skip_lines(self):        """Internal: skip lines until outer boundary if defined."""        if not self.outerboundary or self.done:            return        next_boundary = b"--" + self.outerboundary        last_boundary = next_boundary + b"--"        last_line_lfend = True        while True:            line = self.fp.readline(1<<16)            self.bytes_read += len(line)            if not line:                self.done = -1                break            if line.endswith(b"--") and last_line_lfend:                strippedline = line.strip()                if strippedline == next_boundary:                    break                if strippedline == last_boundary:                    self.done = 1                    break            last_line_lfend = line.endswith(b'\n')     def make_file(self):        """Overridable: return a readable & writable file.         The file will be used as follows:        - data is written to it        - seek(0)        - data is read from it         The file is opened in binary mode for files, in text mode        for other fields         This version opens a temporary file for reading and writing,        and immediately deletes (unlinks) it.  The trick (on Unix!) is        that the file can still be used, but it can't be opened by        another process, and it will automatically be deleted when it        is closed or when the current process terminates.         If you want a more permanent file, you derive a class which        overrides this method.  If you want a visible temporary file        that is nevertheless automatically deleted when the script        terminates, try defining a __del__ method in a derived class        which unlinks the temporary files you have created.         """        if self._binary_file:            return tempfile.TemporaryFile("wb+")        else:            return tempfile.TemporaryFile("w+",                encoding=self.encoding, newline = '\n')  # Test/debug code# =============== def test(environ=os.environ):    """Robust test CGI script, usable as main program.     Write minimal HTTP headers and dump all information provided to    the script in HTML form.     """    print("Content-type: text/html")    print()    sys.stderr = sys.stdout    try:        form = FieldStorage()   # Replace with other classes to test those        print_directory()        print_arguments()        print_form(form)        print_environ(environ)        print_environ_usage()        def f():            exec("testing print_exception() -- <I>italics?</I>")        def g(f=f):            f()        print("<H3>What follows is a test, not an actual exception:</H3>")        g()    except:        print_exception()     print("<H1>Second try with a small maxlen...</H1>")     global maxlen    maxlen = 50    try:        form = FieldStorage()   # Replace with other classes to test those        print_directory()        print_arguments()        print_form(form)        print_environ(environ)    except:        print_exception() def print_exception(type=None, value=None, tb=None, limit=None):    if type is None:        type, value, tb = sys.exc_info()    import traceback    print()    print("<H3>Traceback (most recent call last):</H3>")    list = traceback.format_tb(tb, limit) + \           traceback.format_exception_only(type, value)    print("<PRE>%s<B>%s</B></PRE>" % (        html.escape("".join(list[:-1])),        html.escape(list[-1]),        ))    del tb def print_environ(environ=os.environ):    """Dump the shell environment as HTML."""    keys = sorted(environ.keys())    print()    print("<H3>Shell Environment:</H3>")    print("<DL>")    for key in keys:        print("<DT>", html.escape(key), "<DD>", html.escape(environ[key]))    print("</DL>")    print() def print_form(form):    """Dump the contents of a form as HTML."""    keys = sorted(form.keys())    print()    print("<H3>Form Contents:</H3>")    if not keys:        print("<P>No form fields.")    print("<DL>")    for key in keys:        print("<DT>" + html.escape(key) + ":", end=' ')        value = form[key]        print("<i>" + html.escape(repr(type(value))) + "</i>")        print("<DD>" + html.escape(repr(value)))    print("</DL>")    print() def print_directory():    """Dump the current directory as HTML."""    print()    print("<H3>Current Working Directory:</H3>")    try:        pwd = os.getcwd()    except OSError as msg:        print("OSError:", html.escape(str(msg)))    else:        print(html.escape(pwd))    print() def print_arguments():    print()    print("<H3>Command Line Arguments:</H3>")    print()    print(sys.argv)    print() def print_environ_usage():    """Dump a list of environment variables used by CGI as HTML."""    print("""<H3>These environment variables could have been set:</H3><UL><LI>AUTH_TYPE<LI>CONTENT_LENGTH<LI>CONTENT_TYPE<LI>DATE_GMT<LI>DATE_LOCAL<LI>DOCUMENT_NAME<LI>DOCUMENT_ROOT<LI>DOCUMENT_URI<LI>GATEWAY_INTERFACE<LI>LAST_MODIFIED<LI>PATH<LI>PATH_INFO<LI>PATH_TRANSLATED<LI>QUERY_STRING<LI>REMOTE_ADDR<LI>REMOTE_HOST<LI>REMOTE_IDENT<LI>REMOTE_USER<LI>REQUEST_METHOD<LI>SCRIPT_NAME<LI>SERVER_NAME<LI>SERVER_PORT<LI>SERVER_PROTOCOL<LI>SERVER_ROOT<LI>SERVER_SOFTWARE</UL>In addition, HTTP headers sent by the server may be passed in theenvironment as well.  Here are some common variable names:<UL><LI>HTTP_ACCEPT<LI>HTTP_CONNECTION<LI>HTTP_HOST<LI>HTTP_PRAGMA<LI>HTTP_REFERER<LI>HTTP_USER_AGENT</UL>""")  # Utilities# ========= def valid_boundary(s):    import re    if isinstance(s, bytes):        _vb_pattern = b"^[ -~]{0,200}[!-~]$"    else:        _vb_pattern = "^[ -~]{0,200}[!-~]$"    return re.match(_vb_pattern, s) # Invoke mainline# =============== # Call test() when this file is run as a script (not imported as a module)if __name__ == '__main__':    test()