[ELDK] cramfs issue for hotplugged devices

Batsayan Das batsayan.das at tcs.com
Wed Sep 29 10:02:28 CEST 2010

Say the normal root file system has a file /etc/udhcpc.conf, and I decided 
to put this file in writable tmpfs directory. 

To make a "udhcpc.conf -> /tmpfs/udhcpc.conf"  did the following in the 
root file system

cd etc
mv udhcpc.conf   temp_udhcpc.conf 
ln -s  /tmpfs/udhcpc.conf    udhcpc.con

in the "rcS" file added the following

/bin/mount -t tmpfs -o size=2M tmpfs /tmpfs
cp /etc/temp_udhcpc.conf /tmpfs/udhcpc.conf

I can't find other way without creating temp_udhcpc.conf  file in etc 

Is this the above process is correct for any other file I chose to put it 
in tmpfs? 

Batsayan Das
Tata Consultancy Services
Mailto: batsayan.das at tcs.com
Website: http://www.tcs.com
Experience certainty.   IT Services
                        Business Solutions

Wolfgang Denk <wd at denx.de>
Batsayan Das <batsayan.das at tcs.com>
eldk at lists.denx.de
09/27/2010 07:26 PM
Re: [ELDK] cramfs issue for hotplugged devices

Dear Batsayan Das,

In message 
<OFACAF4A93.614659B5-ON652577AB.00476762-652577AB.0049FB42 at tcs.com> you 
> The above url says "in the root filesystem symbolic links are used to 
> point to their new locations" , my question is how a symbolic link to be 

> created when the source of the symbolic link is not present in the file 
> system

Just create it - the "ln" command does not care whether the target of
the link actually exists or not.

> How cramfs deal with hot plugged device entries in /dev directory? 

Exactly as mentioned above: we use symlinks to redirect accesses to
such files to a writable file system.

Best regards,

Wolfgang Denk

DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
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