magic.py

bugzilla的安装文件

                print >>sys.stderr, '$$', m.groupdict()
                raise
            return
        raise OffsetError(`s`)
    def __call__(self,file=None):
        if self.value is not None : return self.value
        pos = file.tell()
        try:
            if not self.relative : file.seek( self.offset, 0 )
            frmt = Offset.pos_format.get( self.type, 'I' )
            size = struct.calcsize( frmt )
            data = struct.unpack( frmt, file.read( size ) )
            if self.offs : data += self.offs
            return data
        finally:
            file.seek( pos, 0 )
    def __str__(self): return self.source
    def __repr__(self): return 'Offset(%s)' % `self.source`
#end class Offset

class MagicFileError(MagicError): pass

class MagicFile:
    def __init__(self,filename=_magic):
        self.file = None
        self.tests = []
        self.total_tests = 0
        self.load( filename )
        self.ack_tests = None
        self.nak_tests = None
    def __del__(self):
        self.close()
    def load(self,filename=None):
        self.open( filename )
        self.parse()
        self.close()
    def open(self,filename=None):
        self.close()
        if filename is not None :
            self.filename = filename
        self.file = open( self.filename, 'r', BUFFER_SIZE )
    def close(self):
        if self.file :
            self.file.close()
            self.file = None
    def parse(self):
        line_no = 0
        for line in self.file.xreadlines() :
            line_no += 1
            if not line or line[0]=='#' : continue
            line = line.lstrip().rstrip('\r\n')
            if not line or line[0]=='#' : continue
            try:
                x = self.parse_line( line )
                if x is None :
                    print >>sys.stderr, '#[%04d]#'%line_no, line
                    continue
            except:
                print >>sys.stderr, '###[%04d]###'%line_no, line
                raise
            self.total_tests += 1
            level, offset, mtype, test, message = x
            new_test = MagicTest(offset,mtype,test,message,
                    line=line_no,level=level)
            try:
                if level == 0 :
                    self.tests.append( new_test )
                else:
                    self.tests[-1].add( new_test )
            except:
                if 1 :
                    print >>sys.stderr, 'total tests=%s' % (
                            `self.total_tests`,
                    )
                    print >>sys.stderr, 'level=%s' % (
                            `level`,
                    )
                    print >>sys.stderr, 'tests=%s' % (
                            pprint.pformat(self.tests),
                    )
                raise
        else:
            while self.tests[-1].level > 0 :
                self.tests.pop()
    def parse_line(self,line):
        # print >>sys.stderr, 'line=[%s]' % line
        if (not line) or line[0]=='#' : return None
        level = 0
        offset = mtype = test = message = ''
        mask = None
        # get optional level (count leading '>')
        while line and line[0]=='>' :
            line, level = line[1:], level+1
        # get offset
        while line and not line[0].isspace() :
            offset, line = offset+line[0], line[1:]
        try:
            offset = Offset(offset)
        except:
            print >>sys.stderr, 'line=[%s]' % line
            raise
        # skip spaces
        line = line.lstrip()
        # get type
        c = None
        while line :
            last_c, c, line = c, line[0], line[1:]
            if last_c!='\\' and c.isspace() :
                break # unescaped space - end of field
            else:
                mtype += c
                if last_c == '\\' :
                    c = None # don't fuck my brain with sequential backslashes
        # skip spaces
        line = line.lstrip()
        # get test
        c = None
        while line :
            last_c, c, line = c, line[0], line[1:]
            if last_c!='\\' and c.isspace() :
                break # unescaped space - end of field
            else:
                test += c
                if last_c == '\\' :
                    c = None # don't fuck my brain with sequential backslashes
        # skip spaces
        line = line.lstrip()
        # get message
        message = line
        if mime and line.find("\t") != -1:
            message=line[0:line.find("\t")]
        #
        # print '>>', level, offset, mtype, test, message
        return level, offset, mtype, test, message
    def detect(self,file):
        self.ack_tests = 0
        self.nak_tests = 0
        answers = []
        for test in self.tests :
            message = test.run( file )
            if message :
                self.ack_tests += 1
                answers.append( message )
            else:
                self.nak_tests += 1
        if answers :
            return '; '.join( answers )
#end class MagicFile

def username(uid):
    try:
        return pwd.getpwuid( uid )[0]
    except:
        return '#%s'%uid

def groupname(gid):
    try:
        return grp.getgrgid( gid )[0]
    except:
        return '#%s'%gid

def get_file_type(fname,follow):
    t = None
    if not follow :
        try:
            st = os.lstat( fname ) # stat that entry, don't follow links!
        except os.error, why :
            pass
        else:
            if stat.S_ISLNK(st[stat.ST_MODE]) :
                t = 'symbolic link'
                try:
                    lnk = os.readlink( fname )
                except:
                    t += ' (unreadable)'
                else:
                    t += ' to '+lnk
    if t is None :
        try:
            st = os.stat( fname )
        except os.error, why :
            return "can't stat `%s' (%s)." % (why.filename,why.strerror)

    dmaj, dmin = (st.st_rdev>>8)&0x0FF, st.st_rdev&0x0FF

    if 0 : pass
    elif stat.S_ISSOCK(st.st_mode) : t = 'socket'
    elif stat.S_ISLNK (st.st_mode) : t = follow and 'symbolic link' or t
    elif stat.S_ISREG (st.st_mode) : t = 'file'
    elif stat.S_ISBLK (st.st_mode) : t = 'block special (%d/%d)'%(dmaj,dmin)
    elif stat.S_ISDIR (st.st_mode) : t = 'directory'
    elif stat.S_ISCHR (st.st_mode) : t = 'character special (%d/%d)'%(dmaj,dmin)
    elif stat.S_ISFIFO(st.st_mode) : t = 'pipe'
    else: t = '<unknown>'

    if st.st_mode & stat.S_ISUID :
        t = 'setuid(%d=%s) %s'%(st.st_uid,username(st.st_uid),t)
    if st.st_mode & stat.S_ISGID :
        t = 'setgid(%d=%s) %s'%(st.st_gid,groupname(st.st_gid),t)
    if st.st_mode & stat.S_ISVTX :
        t = 'sticky '+t

    return t

HELP = '''%s [options] [files...]

Options:

        -?, --help -- this help
        -m, --magic=<file> -- use this magic <file> instead of %s
        -f, --files=<namefile> -- read filenames for <namefile>
*       -C, --compile -- write "compiled" magic file
        -b, --brief -- don't prepend filenames to output lines
+       -c, --check -- check the magic file
        -i, --mime -- output MIME types
*       -k, --keep-going -- don't stop st the first match
        -n, --flush -- flush stdout after each line
        -v, --verson -- print version and exit
*       -z, --compressed -- try to look inside compressed files
        -L, --follow -- follow symlinks
        -s, --special -- don't skip special files

*       -- not implemented so far ;-)
+       -- implemented, but in another way...
'''

def main():
    import getopt
    global _magic
    try:
        brief = 0
        flush = 0
        follow= 0
        mime  = 0
        check = 0
        special=0
        try:
            opts, args = getopt.getopt(
                    sys.argv[1:],
                    '?m:f:CbciknvzLs',
                    (       'help',
                            'magic=',
                            'names=',
                            'compile',
                            'brief',
                            'check',
                            'mime',
                            'keep-going',
                            'flush',
                            'version',
                            'compressed',
                            'follow',
                            'special',
                    )
            )
        except getopt.error, why:
            print >>sys.stderr, sys.argv[0], why
            return 1
        else:
            files = None
            for o,v in opts :
                if o in ('-?','--help'):
                    print HELP % (
                            sys.argv[0],
                            _magic,
                    )
                    return 0
                elif o in ('-f','--files='):
                    files = v
                elif o in ('-m','--magic='):
                    _magic = v[:]
                elif o in ('-C','--compile'):
                    pass
                elif o in ('-b','--brief'):
                    brief = 1
                elif o in ('-c','--check'):
                    check = 1
                elif o in ('-i','--mime'):
                    mime = 1
                    if os.path.exists( _magic+'.mime' ) :
                        _magic += '.mime'
                        print >>sys.stderr,sys.argv[0]+':',\
                                                        "Using regular magic file `%s'" % _magic
                elif o in ('-k','--keep-going'):
                    pass
                elif o in ('-n','--flush'):
                    flush = 1
                elif o in ('-v','--version'):
                    print 'VERSION'
                    return 0
                elif o in ('-z','--compressed'):
                    pass
                elif o in ('-L','--follow'):
                    follow = 1
                elif o in ('-s','--special'):
                    special = 1
            else:
                if files :
                    files = map(lambda x: x.strip(), v.split(','))
                    if '-' in files and '-' in args :
                        error( 1, 'cannot use STDIN simultaneously for file list and data' )
                    for file in files :
                        for name in (
                                        (file=='-')
                                                and sys.stdin
                                                or open(file,'r',BUFFER_SIZE)
                        ).xreadlines():
                            name = name.strip()
                            if name not in args :
                                args.append( name )
        try:
            if check : print >>sys.stderr, 'Loading magic database...'
            t0 = time.time()
            m = MagicFile(_magic)
            t1 = time.time()
            if check :
                print >>sys.stderr, \
                                        m.total_tests, 'tests loaded', \
                                        'for', '%.2f' % (t1-t0), 'seconds'
                print >>sys.stderr, len(m.tests), 'tests at top level'
                return 0 # XXX "shortened" form ;-)

            mlen = max( map(len, args) )+1
            for arg in args :
                if not brief : print (arg + ':').ljust(mlen),
                ftype = get_file_type( arg, follow )
                if (special and ftype.find('special')>=0) \
                                or ftype[-4:] == 'file' :
                    t0 = time.time()
                    try:
                        t = m.detect( arg )
                    except (IOError,os.error), why:
                        t = "can't read `%s' (%s)" % (why.filename,why.strerror)
                    if ftype[-4:] == 'file' : t = ftype[:-4] + t
                    t1 = time.time()
                    print t and t or 'data'
                    if 0 : print \
                                                        '#\t%d tests ok, %d tests failed for %.2f seconds'%\
                                                        (m.ack_tests, m.nak_tests, t1-t0)
                else:
                    print mime and 'application/x-not-regular-file' or ftype
                if flush : sys.stdout.flush()
        # print >>sys.stderr, 'DONE'
        except:
            if check : return 1
            raise
        else:
            return 0
    finally:
        pass

if __name__ == '__main__' :
    sys.exit( main() )
# vim:ai
# EOF #