Subject: Re: bug#71935: split-string-and-unquote mishandles dired-listing-switches with '

From: Juri Linkov <[email-masked]>
Date: Thu, 04 Jul 2024 19:10:17 +0300

>> 1. (setopt dired-listing-switches "-al --block-size='1")
>> 2. C-x d /tmp/*
>>
>>   /tmp:
>>   wildcard *
>>   /bin/bash: -c: line 0: unexpected EOF while looking for matching `''
>>   /bin/bash: -c: line 1: syntax error: unexpected end of file
>>
>> 3. (setopt dired-listing-switches "-al --block-size=\\'1")
>> 4. C-x d /tmp/
>>
>> Debugger entered--Lisp error: (error "Listing directory failed but ‘access-file’ worked")
>>   error("Listing directory failed but `access-file' worked")
>>   insert-directory("/tmp/" "--dired -N -al --block-size=\\'1" nil t)
>
> I think the part of insert-directory that deals with wildcard lacks
> the call to shell-quote-argument here:
>
> 		      ;; NB since switches is passed to the shell, be
> 		      ;; careful of malicious values, eg "-l;reboot".
> 		      ;; See eg dired-safe-switches-p.
> 		      (call-process
> 		       shell-file-name nil t nil
> 		       shell-command-switch
> 		       (concat (if (memq system-type '(ms-dos windows-nt))
> 				   ""
> 				 "\\") ; Disregard Unix shell aliases!
> 			       insert-directory-program
> 			       " -d "
> 			       (if (stringp switches)
> 				   switches
> 				 (mapconcat #'identity switches " "))
>
> Can you try running each switch through shell-quote-argument?

This part of insert-directory is used only in case of 1-2 above,
i.e. for wildcard '/tmp/*'.  In this case the value of 'switches'
is "--dired -N -al --block-size='1", and 'shell-quote-argument'
returns "--dired\\ -N\\ -al\\ --block-size\\=\\'1" that fails.

For the non-wildcard case of 3-4 above, this doesn't help either.
Using (mapcar 'shell-quote-argument (split-string-and-unquote switches))
on ("--dired" "-N" "-al" "--block-size=\\'1") returns
("--dired" "-N" "-al" "--block-size\\=\\\\\\'1") that fails with

  /bin/ls: unrecognized option '--block-size\=\\\'1'