Finding sysfs mount point

Finding sysfs mount point

[Ian Pilcher]

I'm trying to write a script (invoked via a PROGRAM key) to find the
interface number of a USB serial port.  (See my post in the "udev: rules
using multiple sysfs directories" thread for the reason why.)

To do this I need to look as sysfs.  What's the best way to figure out
where it's mounted?

Also, is it safe to rely on the contents of DEVPATH to find a symbolic
link to the device?

Thanks!

-- 
====================================
Ian Pilcher                                        i.pilcher@comcast.net
====================================



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Re: Finding sysfs mount point

[Greg KH]

On Thu, Apr 28, 2005 at 05:08:02PM -0500, Ian Pilcher wrote:
> I'm trying to write a script (invoked via a PROGRAM key) to find the
> interface number of a USB serial port.  (See my post in the "udev: rules
> using multiple sysfs directories" thread for the reason why.)
> 
> To do this I need to look as sysfs.  What's the best way to figure out
> where it's mounted?

cat /proc/mounts | grep sysfs | cut -f 2 -d " "

works for me.  I think there's a glibc function to retrieve this too.

> Also, is it safe to rely on the contents of DEVPATH to find a symbolic
> link to the device?

Yes, that's what it is there for :)

thanks,

greg k-h


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Re: Finding sysfs mount point

[Christian Bornträger]

On Friday 29 April 2005 06:48, Greg KH wrote:
> cat /proc/mounts | grep sysfs | cut -f 2 -d " "

if sysfs is mounted several times, this results in a non useful value for 
scripting. what about

cat /proc/mounts | grep -m 1 sysfs | cut -f 2 -d " "

to get the first available mountpoint?

cheers

Christian


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Re: Finding sysfs mount point

[Nico -telmich- Schottelius]

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Christian Borntr?ger [Fri, Apr 29, 2005 at 09:09:47AM +0200]:
> On Friday 29 April 2005 06:48, Greg KH wrote:
> > cat /proc/mounts | grep sysfs | cut -f 2 -d " "
> 
> if sysfs is mounted several times, this results in a non useful value for 
> scripting. what about
> 
> cat /proc/mounts | grep -m 1 sysfs | cut -f 2 -d " "
> 
> to get the first available mountpoint?

None of those expamples is reliable, when other paths contain
'sysfs'.

Simply use awk for it, it's build for such things:

   awk '$3 ~ /sysfs/ { print $2; exit }' /proc/mounts

This will catch wrong sysfs mounts and also display only the first
match.

Nico

-- 
Keep it simple & stupid, use what's available.
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