Re: [Discuss-gnuradio] setgid directories / usb permissions

[Javs]

Me too. I created a new mount point at /proc/bus/usb
with usbfs for a regular 'user'account and now I am
able to talk to the usrp with the very first command.

Ahh..such a relief ! Thanks for all your pointers.

Javs

--- Eric Blossom <address@hidden> wrote:

> On Fri, Oct 28, 2005 at 10:01:42AM -0600,
> Robitaille, Michael wrote:
> > Finally got GNU Radio compiled and working with
> the USRP so I am out of the
> > wood for now.
> 
> Great!
> 
> > I installed it in the 'standard' location,
> unfortunately I could do that
> > only as the root and I can only run GnuRadio as
> root.  I can't even use
> > 'sudo' to run usrp_oscope.py.
> 
> Please remind me which distribution you're using. 
> FC4?
> 
> Generally speaking, having to run as root reflects a
> permission problem
> on /proc/bus/usb/ and files below.  The fix is
> distribution
> dependent.  I've generally had success by adding
> myself to group "usb"
> and then making sure that "usb" was the group for
> all those files.
> The stuff under /proc/bus/usb is created by the
> usbfs kernel module,
> and there are mount time options that set the gid
> and perms for those
> files.  Look under /etc/rc.d and find out where
> usbfs is mounted.
> 
>   address@hidden init.d]$ grep usbfs *
>   usb:    action "Mount USB filesystem" mount -t
> usbfs -o devmode=0664,devgid=43 none /proc/bus/usb
> 
>   address@hidden eb]$ grep 43 /etc/group
>   usb:x:43:eb
> 
> The magic usbfs mount options are defined in the
> kernel source in
> linux/drivers/usb/core/inode.c  (Yes, I know you
> shouldn't have to
> look at kernel source to figure this stuff out, but
> hey, at least we
> *do* have the source available.)
> 
> static match_table_t tokens = {
>       {Opt_devuid, "devuid=%u"},
>       {Opt_devgid, "devgid=%u"},
>       {Opt_devmode, "devmode=%o"},
>       {Opt_busuid, "busuid=%u"},
>       {Opt_busgid, "busgid=%u"},
>       {Opt_busmode, "busmode=%o"},
>       {Opt_listuid, "listuid=%u"},
>       {Opt_listgid, "listgid=%u"},
>       {Opt_listmode, "listmode=%o"},
>       {Opt_err, NULL}
> };
> 
> They probably ought to be documented in
> linux/Documentation/filesystems
> along with the rest of the filesystems and have a
> man page.
> 
> 
> > Eric wrote:
> > > > Depends on your setup.  I don't install with
> sudo (being generally
> > > > paranoid), and have arranged things so that
> I'm in a group that has
> > > > write access to everything under /usr/local. 
> Judicious use of 
> > > 
> > > >  chmod g+s on directories under there is
> useful.
> >  
> > > Shell programming 101:  
> >  
> > >  $ find /usr/local/ -type d -print0 | xargs -0
> chgrp <some-group-you-like>
> > >  $ find /usr/local/ -type d -print0 | xargs -0
> chmod g+rwxs
> >  
> > > Figuring out what the setgid bit on a directory
> does is left as an
> > exercise ;)
> > 
> > Sid not - exercise;
> > 
> > Per my old Unix book;
> > 
> > Unless the set group ID (sgid) permission of an
> executable file are set, the
> > process created is assigned your uid and gid at
> its real and effective uid
> > and real and effective gid, respectively. File
> access for a process is
> > determined by its effective uid and effective gid.
> 
> Note that we are setting the setgid bit on a
> directory, *not* a
> regular file.  What it does is ensure that all files
> and directories
> created in the that directory have their group set
> to the group of
> parent directory.
> 
> 
> Here's what my setup looks like:
> 
>   address@hidden eb]$ id
>   uid=502(eb) gid=502(eb)
> groups=10(wheel),43(usb),502(eb)
> 
> Note that my gid is 502(eb), but that I'm also a
> member of
> wheel and usb.
> 
>   address@hidden eb]$ ls -ld /usr/local/bin
>   drwxrwsr-x  2 root wheel 4096 Oct 24 18:24
> /usr/local/bin
> 
> Given this setup, I can write files into
> /usr/local/bin, and even
> though my gid is 502(eb), the installed files end up
> with group 10(wheel).
> 
> E.g.,  
> 
>   address@hidden eb]$ ls -ld /usr/local/bin
>   drwxrwsr-x  2 root wheel 4096 Oct 24 18:24
> /usr/local/bin
>   address@hidden eb]$ touch /usr/local/bin/foo
>   address@hidden eb]$ ls -l /usr/local/bin/foo
>   -rw-rw-r--  1 eb wheel 0 Oct 28 09:41
> /usr/local/bin/foo
>   address@hidden eb]$ rm /usr/local/bin/foo
> 
> 
> > After making the changes to /usr/local based on my
> new group, I tried to
> > build the base line software needed and got the
> following type of error
> > while making sdcc:
> > 
> > make -C `dirname hc08/port.a`
> > make[2]: Entering directory
> `/opt/GnuRadio/sdcc/src/hc08'
> > make[2]: Nothing to be done for `all'.
> > make[2]: Leaving directory
> `/opt/GnuRadio/sdcc/src/hc08'
> > 
> > /usr/bin/install -c -d /usr/local/bin
> > 
> > /usr/bin/install: cannot change permissions of
> `/usr/local/bin': Operation
> > not permitted
> 
> Wrong permissions on /usr/local/bin, and/or you're
> not a member of the
> right group.
> 
> > Making myself root solved this problem but now I
> can't run the gnuradio
> > software except as root.
> > 
> > Even when I use 'sudo' to run usrp_oscope.py, I
> get the error
> > 
> > ImportError: libwx_gtk2d_xrc-2.6.so.0: cannot open
> shared object file: No
> > such file or directory
> 
> > The file is in the /urs/local/bin and my
> LD_LIBRARY_PATH is set to that
> > location.  I set the same environment variables
> for both my regular user and
> > root.
> 
> >From man sudo:
> 
> SECURITY NOTES
>        sudo tries to be safe when executing external
> commands.  Variables that
>        control how dynamic loading and binding is
> done can be used to subvert
>        the program that sudo runs.  To combat this
> the LD_*, _RLD_*,
>        SHLIB_PATH (HP-UX only), and LIBPATH (AIX
> only) environment variables
>        are removed from the environment passed on to
> all commands executed.
> 
> 
> Recommended action:  Fix the permissions on the
> stuff in /proc/bus/usb
> 
> > If I don't use 'sudo' I get even more errors.  I
> think that they are related
> > to usb access. I try to use the fstab per another
> post and it did not seem
> > to help.
> 
> On FC2, I know that the mount command didn't honor
> the perms and gid
> mount options to usbfs.  Not sure if it is fixed in
> FC4.
> 
> Celebrating the joys of *nix system administration!
> 
> Eric
> 
> 
> _______________________________________________
> Discuss-gnuradio mailing list
> address@hidden
>
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> 



                
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