permission, read only directory, logged in as root

ted_chou12 · 08-22-2010, 02:02 PM

Hi all, its my first time posting here:
I am having problems trying to create a file or move a file to the directory /bin/codepages/here

Code:

# cat>/bin/codepages/map
-sh: can't create /bin/codepages/map: Read-only file system

I want to add other encoding lang here, eg utf8,cp950..etc.
Yes, I am logged in as root, the permission of this folder seems to be "rwxr-xr-x" or 0755, owner root.
Here is the mount information:

Code:

# mount
rootfs on / type rootfs (rw)
/dev/root on / type jffs2 (ro)
tmpfs on /var type tmpfs (rw)
tmpfs on /tmp type tmpfs (rw)
tmpfs on /usb type tmpfs (rw)
none on /proc type proc (rw)
mdev on /dev type tmpfs (rw)
devpts on /dev/pts type devpts (rw)
sysfs on /sys type sysfs (rw)
tmpfs on /etc type tmpfs (rw)
/dev/sda1 on /usb/sda1 type fuseblk (rw,noatime,user_id=0,group_id=0,allow_other)

I tried to search for this problem, I know there are plenty cases previously, but they seem to say something about fsck after remount, if that is the case, then how do you do that? via putty? or add it to the bootup script (which is what file and path?). I am very new to linux, please bare with me.
Thanks!
Ted

r0b0 · 08-22-2010, 02:46 PM

Hi Ted and welcome to LQ!

Your root directory is mounted read-only. That means that even root will not be able to write there, including creating new files. As to why is your root directory mounted read-only, we would need to know a little bit more about your system. What is it? It looks cool to me - jffs2 filesystem???

It should be possible to re-mount the filesystem in read-write mode. I would try the command

Code:

# mount /dev/root / -o remount=rw

Elv13 · 08-22-2010, 02:49 PM

Distribution? It may be SELinux or AppArmor or just some kind of stupidity mask to prevent working on critical directories. When you said you were logged in as root, with the root using name, su, "su -" or sudo?

EDIT: the above poster saw something that I did not, he/she is right, I just lokked at rootfs, skipped /dev/root

ted_chou12 · 08-22-2010, 03:10 PM

Hi, thank you for your quick response! This is a very simple NAS machine, I'm trying on a user DIY firmware, the system is here:

Code:

# uname -a
Linux nas 2.6.16-gazineu #13 Mon Jun 21 21:43:59 BRT 2010 armv4l GNU/Linux

I tried the command line you gave me, but the output seems to be weird:

Code:

# mount /dev/root / -o remount=rw
mount: mounting /dev/root on / failed: Invalid argument

Here is the fstab info:

Code:

# cat /etc/fstab
/dev/ram0       /               ext2    defaults        0       0
none            /proc           proc    defaults        0       0
none            /dev/pts        devpts  defaults        0       0

I just read from an online article, defaults means is rw, so shouldn't that mean I can write into the root?
Thanks again!!!

Ted