Writes with pf do nothing

[Hi-Angel]

Environment

Пт 29 янв 2021 09:22:46 MSK
radare2 5.0.0 0 @ linux-x86-64 git.5.0.0
commit: unknown build: 2021-01-21__00:15:48
Linux x86_64

Description

When a value is overwritten with pf command (for example pf.foo=7), the command silently exits as if it succeeded in writing, but displaying the "overwritten" field shows older values. This came up yesterday on IRC, and apparently is a bug.

Test

You'll need some PE executable, in the testcase I'm using an arbitrary one distributed in WINE project.

 $ cp /usr/lib32/wine/notepad.exe .
 $ r2 -nnw notepad.exe
 -- radare2 is power, France is pancake.
[0x00000000]> pf.pe_image_file_header.characteristics
      characteristics : 0x00000012 = characteristics (bitfield) = 0x00000000 :
[0x00000000]> pf.pe_image_file_header.characteristics=7
[0x00000000]> pf.pe_image_file_header.characteristics
      characteristics : 0x00000012 = characteristics (bitfield) = 0x00000000 :
[0x00000000]>

Expected

The last command will show characteristics field has new value 7

Actual

The last command shows characteristics field has older value 0

[Hi-Angel]

So, I wanted to bisect it. First, I tried out master, commit 590eaa6 from yesterday. Still same problem. Then I checked out branch/tag 3.1.2 from 2018, built it, an tried that out.Well, it didn't work either, so I suspect it have never worked.

[Hi-Angel]

FTR: after discussion in Telegram it turned out that assignment with pf sometimes works, sometimes doesn't. In particular, this example was given where I confirm that it works:

[Hi-Angel]

Okay, just so this info won't get lost: a week ago Anymy user in chat did some research on this problem, and found, quoting:

i found... problem in bitfield. bitfield and enums don't implemented write functional. You can write in other types, but not in bitfields

Also strings (not zero terminated)

[trufae]

Theres a warning now, but it should be easy to implement the write case for those types. Any volunteer? :)