Re: permission denied: /gnu/store/...guile...

[rekado]

---- On Fri, 22 May 2015 05:53:51 +0800 Ludovic Courtès<address@hidden> wrote 
---- 
 > Could you try this: 
 >  
 > --8<---------------cut here---------------start------------->8--- 
 > (chdir "/tmp") 
 > (setgroups #()) 
 > (setgid 30000) 
 > (setuid 30001) 
 > (pk 'uid/gid (getuid) (getgid)) 
 > (pk 'euid/egid (geteuid) (getegid)) 
 > (let loop ((i 3)) 
 >   (when (< i 1024) 
 >     (false-if-exception (close-fdes i)) 
 >     (loop (+ 1 i)))) 
 > (execl "/gnu/store/cnqmkmj40jmssnx6fkf9n0n3bqj5x426-guile-2.0.11/bin/guile" 
 > "guile" 
 >        "-c" "(pk 'running (getuid) (geteuid))") 
 > --8<---------------cut here---------------end--------------->8--- 
 >  
 > and then as root run: 
 >  
 >   # guile the-above-file.scm 
 >  
 > It should return zero and print: 
 >  
 > --8<---------------cut here---------------start------------->8--- 
 > ;;; (uid/gid 30001 30000) 
 >  
 > ;;; (euid/egid 30001 30000) 
 >  
 > ;;; (running 30001 30001) 
 > --8<---------------cut here---------------end--------------->8--- 

I ran it in a guile REPL (as root) and I got the first two outputs, but an 
error on (execl ...).  It's an unhelpful message:

    ERROR: In procedure execl:
    ERROR: In procedure execl: Permission denied

The backtrace just shows me the line that failed.

When I save it in a file and run that with guile as root I get this error after 
the first two output lines:

    Backtrace:
    In ice-9/boot-9.scm:
      157: 7 Exception thrown while printing backtrace:
    ERROR: In procedure private-lookup: Module named (system vm frame) does not 
exist

    ERROR: In procedure execl:
    ERROR: In procedure execl: Permission denied

That's all.