add a script to clean up files "binned" by msys2-runtime

[jeremyd2019]

Updating core packages (specifically pacman.exe and msys-2.0.dll I think) results in oddly-named files in the "recycle bin" directory (see https://github.com/msys2/msys2-runtime/blob/abcb3c6c0f330ac7568956b2be6bf3376517bb56/winsup/cygwin/syscalls.cc#L342). These files don't ever seem to get cleaned up, or indeed result as showing anything in the UI recycle bin. Hence, there should be some way to clean them up.

I made a simple script to do this (https://gist.github.com/jeremyd2019/4984ff0fa1f6fd8c99d7b8b244c52088)

#!/bin/bash -e

shopt -s nullglob

root="$(cygpath -w /)"
root="$(cygpath -u "${root:0:2}")"

trash=("${root}/\$Recycle.Bin/S-1-"*/$'.\355\261\255'*)

if (( ${#trash[@]} )); then
  ls -la "${trash[@]}"
  read -r -p "Remove? (y/N) "

  if [[ "${REPLY^^}" == "Y" ]]; then
    rm -f "${trash[@]}"
  fi
fi

This script wouldn't work right if the root of the volume is not the drive letter (like, a volume mounted on a directory). Maybe some other edge cases

I don't know where this should live though (filesystem? maybe pacman-contrib just because I associate this with paccache for regular cleanup operations).

Another idea that I keep thinking of is, if the file absolutely cannot be deleted, maybe msys2-runtime could register it for deletion on reboot (with MoveFileEx with lpNewFileName NULL and MOVEFILE_DELAY_UNTIL_REBOOT flag). But I figure somebody would have tried that in cygwin at some point already...

[Biswa96]

Updating core packages results in oddly-named files in the "recycle bin" directory

I have not seen files in recycle bin related to msys2 or cygwin since first time using them.

[jeremyd2019]

Try the script (or the pattern from the script, usually ls -l /c/\$Recycle.Bin/S-1-*/$'.\355\261\255'*). They don't show up in the Windows UI for the recycle bin, so it's not at all obvious that they're there

[Biswa96]

Could you provide any example output of that command? I have only desktop.ini files in there and could try to reproduce the issue with a new msys2 installation.

[jeremyd2019]

I was actually just stepping through the cygwin code in gdb, so I have a bit of a standalone reproducer:

cp /usr/bin/sleep.exe .
./sleep 1000 &
rm -f sleep.exe
ls -la /d/\$Recycle.Bin/S-1-*/$'.\355\261\255'*

-rwxr-xr-x 1 XXX None 36003 May 26 23:05 '/d/$Recycle.Bin/S-1-5-21-XXX/.'$'\355\261\255\355\261\263\355\261\271\355\261\263''300000000017db0aa9908ed6033f1264'

[Biswa96]

I can reproduce the issue with that command. Here is an example of those weird file. /f is the partition where msys2 was installed for testing.

$ tree -a /f/\$RECYCLE.BIN/
/f/$RECYCLE.BIN/
└── S-1-5-21-1390408910-2694286881-1732342665-1001
    ├── .\156155\156163\156171\156163006e00000003d55a67694fe0c9892f4e
    ├── .\156155\156163\156171\156163006f0000000398cd92cba531c0fd489f
    ├── .\156155\156163\156171\15616300ba0000000383b3e888f6746f72d25f
    └── desktop.ini

Nice work btw, jeremy ❤️

[jeremyd2019]

Another idea that I keep thinking of is, if the file absolutely cannot be deleted, maybe msys2-runtime could register it for deletion on reboot (with MoveFileEx with lpNewFileName NULL and MOVEFILE_DELAY_UNTIL_REBOOT flag). But I figure somebody would have tried that in cygwin at some point already...

As I kind of expected, docs suggest MOVEFILE_DELAY_UNTIL_REBOOT only works from an elevated context. Maybe something in cygwin could try to delete these files on future startups? Or a script in /etc/profile.d to clean them up on future shell launches, but I am concerned that it could be impossible for a script to find the correct recycle.bin directory in every edge case that cygwin tries to handle.

[jeremyd2019]

I've been considering this more, and trying to figure out how to replicate what cygwin does to find the recycle bin. The hardest part to script seems to be to get a list of volume mount points. This is what I've come up with so far:

mountvol |
sed -ne '/^Possible values for VolumeName/,${/^\s\{8\}/{s///;/^\*\*\*/!p}}' |
cygpath -uf - |
xargs -i find '{}' -maxdepth 1 -iname '$Recycle.Bin' -print0 |
find -files0-from - -maxdepth 2 -name $'.\uDC6D\uDC73\uDC79\uDC73*' -o -name '.msys*'

Allowing for making a C utility to get the volume mount points as \0-delimited cygwin paths (https://gist.github.com/jeremyd2019/8e088a72dfef44ee29ed3442957c1e65), this becomes:

./volumes |
find -files0-from - -maxdepth 1 -iname '$Recycle.Bin' -print0 |
find -files0-from - -maxdepth 2 -name $'.\uDC6D\uDC73\uDC79\uDC73*' -o -name '.msys*'

(for the record, on upstream cygwin the names would be -name $'.\uDC63\uDC79\uDC67*' -o -name '.cyg*')

[jeremyd2019]

https://cygwin.com/pipermail/cygwin/2024-June/256081.html - see if upstream has any more ideas