Re: jed doesn't maintain group owner

[V01D <phreakuencies@xxxxxxxxx>]

John E. Davis wrote:
> V01D <phreakuencies@xxxxxxxxx> wrote:
> > [root@pris kickstart]# chgrp nobody config.xml
> > [root@pris kickstart]# ls -l config.xml
> > -rw-rw-r-- 1 v01d nobody 735 2006-07-28 20:56 config.xml
> > [root@pris kickstart]# exit
> > [v01d@pris kickstart]$ jed config.xml             (edit & save here)
> > [v01d@pris kickstart]$ ls -l config.xml
> > -rw-rw-r-- 1 v01d users 735 2006-07-28 20:57 config.xml
>
> Another user reported this problem and I have been able to reproduce
> it.  Unfortunately, I do not believe there is anything I can do about
> it.  Unless you are a member of the group that you are trying to
> preserve, or running with the proper privileges, the chown system call
> will fail.  In fact, here is what the man page says about chown:
>
>     These  system calls change the owner and group of the file specified by
>     path or by  fd.   Only  a  privileged  process  (Linux:  one  with  the
>     CAP_CHOWN  capability)  may change the owner of a file.  The owner of a
>     file may change the group of the file to any group of which that  owner
>     is  a  member.  A privileged process (Linux: with CAP_CHOWN) may change
>     the group arbitrarily.
>
> You can put
>
>    BACKUP_BY_COPYING = 1;
>
> in your .jedrc file.  Then jed will create a backup file by coping it,
> and the overwrite the new file, preserving its group id.  However, the
> group will not be preserved for the backup file.  For example, you
> should see something like:
>
>   [v01d@pris kickstart]$ ls -l config.xml*
>   -rw-rw-r-- 1 v01d nobody 735 2006-07-28 20:56 config.xml
>   -rw-rw-r-- 1 v01d users 735 2006-07-28 20:57 config.xml~
>
> --John
>
> --------------------------
> To unsubscribe send email to <jed-users-request@xxxxxxxxxxx> with
> the word "unsubscribe" in the message body.
> Need help? Email <jed-users-owner@xxxxxxxxxxx>.

But why would you need to call chown()? If I open a file, write/read it 
and then close it, the permissions remain intact. I mean, if I compile 
this on C++:

#include <iostream>
#include <cstdio>

int main(void) {
        FILE* f = fopen("test.file", "r+");
        char a = '@';
        fwrite(&a, 1, 1, f);
        fclose(f);
}

and create a file test.file with touch with the following permissions:
-rw-rw-r-- 1 v01d nobody 1 2006-08-03 16:50 test.file

you can see that it doesn't change them:

[v01d@pris ~]$ g++ -o test.out test.cpp
[v01d@pris ~]$ ls -l test.file
-rw-rw-r-- 1 v01d nobody 1 2006-08-03 16:52 test.file
[v01d@pris ~]$ ./test.out
[v01d@pris ~]$ ls -l test.file
-rw-rw-r-- 1 v01d nobody 1 2006-08-03 16:52 test.file
[v01d@pris ~]$ cat test.file
@[v01d@pris ~]$

Although I don't know how jed handles files.

Matt.

--------------------------
To unsubscribe send email to <jed-users-request@xxxxxxxxxxx> with
the word "unsubscribe" in the message body.
Need help? Email <jed-users-owner@xxxxxxxxxxx>.