bug#66531: [PATCH] ftw: Fix getuid-or-false, getgid-or-false macros.

[Ludovic Courtès]

Tomas Volf <wolf@wolfsden.cz> skribis:

> Both macros were missing a quote for the procedure call, causing the
> actual return value to be compiled into the ftw.go, instead of the
> procedure call.  Snippet from disassembly of ftw.go does confirm that:
>
>   55    (make-immediate 2 3990)         ;; 997                at 
> ice-9/ftw.scm:319:46
>   56    (make-long-immediate 1 120002)  ;; 30000              at 
> ice-9/ftw.scm:320:46
>
> That effectively prevented ftw from entering directories without access
> for others.  Simple reproduction:
>
>     scheme@(guile-user)> ,use (ice-9 ftw)
>     scheme@(guile-user)> (mkdir "/tmp/xxxx")
>     scheme@(guile-user)> (chmod "/tmp/xxxx" #o0700)
>     scheme@(guile-user)> (ftw "/tmp/xxxx" (lambda (_ __ f) (pk f) #t))
>
>     ;;; (directory-not-readable)
>     $1 = #t
>     scheme@(guile-user)> (system "ls -al /tmp/xxxx")
>     total 0
>     drwx------ 1 wolf wolf   0 Oct 11 22:54 .
>     drwxrwxrwt 1 root root 888 Oct 11 22:54 ..
>     $2 = 0
>
> The fix is to quote the procedure call, leading to the intended
> behavior.
>
> This fixes bug 55344.
>
> * module/ice-9/ftw.scm (getuid-or-false): Quote the (getuid).
> (getgid-or-false): Quote the (getgid).

Applied, thanks!