The function FileStructure.struntil returns one byte less for no apparent reason. For example, when I request fp.struntil("flags") I expect to get all 8 bytes of the flags struct.

Tested in the pwntools:stable dockercontainer

pwntools@541d39158471:/$ python
Python 3.10.12 (main, Nov 20 2023, 15:14:05) [GCC 11.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from pwn import *
>>> context.clear(arch="amd64")
>>> fp = FileStructure()
>>> payload = fp.struntil("flags")
>>> len(payload)
7

-> I only got 7 bytes

Reason

In pwnlib/filepointer.py the last byte gets truncated

    def struntil(self,v):
[...]
        return structure[:-1]

Proposed fix

Either remove the [:-1] or write it in the documentation why the function is supposed to behave this way.