Command capture bug in linux_procfs save strategy

[mdeguzis]

For example, run:

vim --cmd "set pythonthreehome=/usr/bin/python3" /tmp/a 

Then check ps:

 ps -auwwx | grep vim
deguzim  52230  0.3  0.0 164936 12452 pts/0    S+   17:47   0:00 vim --cmd set pythonthreehome=/usr/bin/python3 /tmp/a   

They ideally need to use /proc//cmdline:

$ for i in /proc/5348*/ 
do
    basename "$i"
    < $i/cmdline xargs -0 zsh -c 'printf "\t%q" "$0" "$@"'
    printf '\n'
done

Or just one PID:

cat /proc/53482/cmdline | xargs -0 zsh -c 'printf "\t%q" "$0" "$@"'

Output:

53482
        vim      --cmd   set\ pythonthreehome=/apollo/env/envImprovement/python3.8       /tmp/a

This is a valid command:

vim     --cmd   set\ pythonthreehome=/apollo/env/envImprovement/python3.8       /tmp/a

man printf

%q ARGUMENT is printed in a format that can be reused as shell input, escaping non-print‐
able characters with the proposed POSIX $'' syntax.

[bruno-]

Try using linux_procfs strategy for saving commands:

set @resurrect-save-command-strategy "linux_procfs"

All the available strategies are in save_command_strategies/ dir in the repo.

I just realized we don't have any docs for this... if you have some time to briefly explain the steps you did to try this, a PR would be welcome.

[mdeguzis]

I saved again and see now it's the command without args

pane    work    1       :project-tests      0       :-      0       :/workplace/deguzim/project/src/project 1       vim     :
pane    work    1       :project-tests      0       :-      1       :/workplace/deguzim/project/src/project 0       zsh     :

With that "linux_procfs" outputs, isn't quite right it seems. Can you test what I have below? Would you accept a PR?

upsteam:

$ cat /proc/40353/cmdline | xargs -0 printf "%q "
printf: %q: invalid conversion specification

$ cat /proc/40353/cmdline                        
vim--cmdset pythonthreehome=/apollo/env/envImprovement/python3.8/home/deguzim/.tmux.conf%

Proposed:

$ cat /proc/40353/cmdline | xargs -0 bash -c 'printf "%q " "$0" "$@"'                           
vim --cmd set\ pythonthreehome=/apollo/env/envImprovement/python3.8 /home/deguzim/.tmux.conf

This 100% did the trick for me locally:

   14 full_command() {
   15     [[ -z "$COMMAND_PID" ]] && exit 0
~  16     #cat /proc/${COMMAND_PID}/cmdline | xargs -0 printf "%q "
+  17     cat /proc/${COMMAND_PID}/cmdline | xargs -0 bash -c 'printf "%q " "$0" "$@"'
   18 }

%q: escape/substitution
$0: command basename (e.g. vim)
$@: the rest of the full command

The original command doesn't save the full args.

When I did a restore after tmux kill-server && rm -rf /tmp/tmux-*, it worked perfect.

Note that this will not work:

cat /proc/${COMMAND_PID}/cmdline | xargs -0 printf "%q " "$0" "$@"

Some reasoning for this subshell usage can be found here: https://unix.stackexchange.com/a/567021

[bruno-]

Hi,

I'm not on Linux so I can't test this easily.

Yes, a PR for this is welcome.

[bruno-]

Just please document why bash -c with those printf interpolations is used. A link to that stackexchange topic in the comments should suffice.

[mdeguzis]

submitted #450

[bruno-]

We just merged #450, so I think this one can be closed.