125 lines
4.4 KiB
Python
125 lines
4.4 KiB
Python
"""
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Tar archive parser.
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Author: Victor Stinner
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"""
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from lib.hachoir_parser import Parser
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from lib.hachoir_core.field import (FieldSet,
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Enum, UInt8, SubFile, String, NullBytes)
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from lib.hachoir_core.tools import humanFilesize, paddingSize, timestampUNIX
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from lib.hachoir_core.endian import BIG_ENDIAN
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import re
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class FileEntry(FieldSet):
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type_name = {
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# 48 is "0", 49 is "1", ...
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0: u"Normal disk file (old format)",
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48: u"Normal disk file",
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49: u"Link to previously dumped file",
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50: u"Symbolic link",
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51: u"Character special file",
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52: u"Block special file",
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53: u"Directory",
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54: u"FIFO special file",
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55: u"Contiguous file"
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}
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def getOctal(self, name):
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return self.octal2int(self[name].value)
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def getDatetime(self):
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"""
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Create modification date as Unicode string, may raise ValueError.
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"""
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timestamp = self.getOctal("mtime")
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return timestampUNIX(timestamp)
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def createFields(self):
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yield String(self, "name", 100, "Name", strip="\0", charset="ISO-8859-1")
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yield String(self, "mode", 8, "Mode", strip=" \0", charset="ASCII")
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yield String(self, "uid", 8, "User ID", strip=" \0", charset="ASCII")
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yield String(self, "gid", 8, "Group ID", strip=" \0", charset="ASCII")
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yield String(self, "size", 12, "Size", strip=" \0", charset="ASCII")
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yield String(self, "mtime", 12, "Modification time", strip=" \0", charset="ASCII")
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yield String(self, "check_sum", 8, "Check sum", strip=" \0", charset="ASCII")
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yield Enum(UInt8(self, "type", "Type"), self.type_name)
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yield String(self, "lname", 100, "Link name", strip=" \0", charset="ISO-8859-1")
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yield String(self, "magic", 8, "Magic", strip=" \0", charset="ASCII")
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yield String(self, "uname", 32, "User name", strip=" \0", charset="ISO-8859-1")
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yield String(self, "gname", 32, "Group name", strip=" \0", charset="ISO-8859-1")
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yield String(self, "devmajor", 8, "Dev major", strip=" \0", charset="ASCII")
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yield String(self, "devminor", 8, "Dev minor", strip=" \0", charset="ASCII")
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yield NullBytes(self, "padding", 167, "Padding (zero)")
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filesize = self.getOctal("size")
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if filesize:
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yield SubFile(self, "content", filesize, filename=self["name"].value)
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size = paddingSize(self.current_size//8, 512)
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if size:
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yield NullBytes(self, "padding_end", size, "Padding (512 align)")
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def convertOctal(self, chunk):
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return self.octal2int(chunk.value)
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def isEmpty(self):
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return self["name"].value == ""
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def octal2int(self, text):
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try:
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return int(text, 8)
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except ValueError:
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return 0
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def createDescription(self):
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if self.isEmpty():
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desc = "(terminator, empty header)"
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else:
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filename = self["name"].value
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filesize = humanFilesize(self.getOctal("size"))
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desc = "(%s: %s, %s)" % \
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(filename, self["type"].display, filesize)
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return "Tar File " + desc
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class TarFile(Parser):
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endian = BIG_ENDIAN
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PARSER_TAGS = {
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"id": "tar",
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"category": "archive",
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"file_ext": ("tar",),
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"mime": (u"application/x-tar", u"application/x-gtar"),
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"min_size": 512*8,
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"magic": (("ustar \0", 257*8),),
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"subfile": "skip",
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"description": "TAR archive",
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}
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_sign = re.compile("ustar *\0|[ \0]*$")
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def validate(self):
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if not self._sign.match(self.stream.readBytes(257*8, 8)):
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return "Invalid magic number"
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if self[0].name == "terminator":
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return "Don't contain any file"
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try:
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int(self["file[0]/uid"].value, 8)
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int(self["file[0]/gid"].value, 8)
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int(self["file[0]/size"].value, 8)
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except ValueError:
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return "Invalid file size"
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return True
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def createFields(self):
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while not self.eof:
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field = FileEntry(self, "file[]")
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if field.isEmpty():
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yield NullBytes(self, "terminator", 512)
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break
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yield field
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if self.current_size < self._size:
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yield self.seekBit(self._size, "end")
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def createContentSize(self):
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return self["terminator"].address + self["terminator"].size
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