Issue with memory watch (fail to show)

[arvyanh]

• Did you use the latest version of GEF from dev branch?
• Is your bug specific to GEF (not GDB)? - Try to reproduce it running gdb -nx
• Did you read the documentation first?
• Did you check issues (including
  the closed ones) - and the PR?

Step 1: Describe your environment

───────────────────────────── Runtime environment ──────────────────────────────

• GDB: 10.2
• Python: 3.8.10 - final
• OS: Linux - 5.8.0-59-generic (x86_64)
  ──────────────────────────────────────────────

Step 2: Describe your problem

Steps to reproduce

1. open executable
2. watch a memory

Minimalist test case

     11      int* heap = malloc(sizeof(int)*1024);
     12
             // i=0x0
 →   13      for(int i = 0; i < 1024; i++){
     14          heap[i] = i;
     15      }
     16

Observed Results

• What happened? This could be a description, log output, etc.
  No memory dump are showed, and shows a hexdump error

...
───────────────────────────────────────────────────────────────────────── memory:0x5555555592a0 ────
usage: hexdump qword [-h] [--reverse] [--size SIZE] [address]
hexdump qword: error: unrecognized arguments: 16

─────────────────────────────── Exception raised ───────────────────────────────
RuntimeWarning:
───────────────────────────── Detailed stacktrace ──────────────────────────────
↳ File "/home/arvyanh/script/misc/gdb-dash/gef-git/gef.py", line 2603, in FakeExit()
    →     raise RuntimeWarning
↳ File "/usr/lib/python3.8/argparse.py", line 2520, in exit()
    →     _sys.exit(status)
↳ File "/usr/lib/python3.8/argparse.py", line 2533, in error()
    →     self.exit(2, _('%(prog)s: error: %(message)s\n') % args)
↳ File "/usr/lib/python3.8/argparse.py", line 1783, in parse_args()
    →     self.error(msg % ' '.join(argv))
↳ File "/home/arvyanh/script/misc/gdb-dash/gef-git/gef.py", line 2653, in wrapper()
    →     parsed_args = parser.parse_args(*(args[1:]))
↳ File "/home/arvyanh/script/misc/gdb-dash/gef-git/gef.py", line 2557, in wrapper()
    →     return f(*args, **kwargs)
↳ File "/home/arvyanh/script/misc/gdb-dash/gef-git/gef.py", line 239, in wrapper()
    →     return f(*args, **kwargs)
↳ File "/home/arvyanh/script/misc/gdb-dash/gef-git/gef.py", line 4201, in invoke()
    →     bufferize(self.do_invoke)(argv)

reverts to a early version seems to solve the issue: (I choose a random version earlier e.g. 6b82ee6 Jan 9, 2021)

The online test version also seems to work

Expected results

• What did you expect to happen?
  memory show correctly.

Traces

all the info above are from debug mode

[theguy147]

can confirm that memory watch does not currently work (for me). A quick git bisect shows me that it doesn't work anymore since commit e38f7dd.

[theguy147]

There is some mess with the syntax of the hexdump command since that commit.

memory watch calls hexdump [WORD_LENGTH] [LOCATION] [SIZE] for non-pointers. But this syntax doesn't work anymore since that commit. Now it should be (?) hexdump [WORD_LENGTH] [LOCATION] [--size SIZE].

Also the _syntax_ and _example_ for HexdumpCommand don't match for WORD_LENGTH (and are seemingly both currently wrong in regards to SIZE).

EDIT:

also with the new argparsing when entering a faulty hexdump command we get another completely different usage message

usage: hexdump byte [-h] [--reverse] [--size SIZE] [address]

which one should actually be used in the future?

[theguy147]

I guess a test for the memory watch command should be implemented once the expected syntax has been defined.

[hugsy]

I guess a test for the memory watch command should be implemented once the expected syntax has been defined.

100% - and to be honest I thought it was 😁

[theguy147]

@arvyanh Can you update GEF and see if your issue has been solved?

[arvyanh]

@arvyanh Can you update GEF and see if your issue has been solved?

Yes, I think its working now