I've updated my openwrt firmware using the web interface. Now the web interface is unreachable.
I lost my root password so i started my router (wr1043nd) in failsafe mode, but the mount_root command is not working:
$mount_root
""/bin/ash: mount_root: not found""
Any clue? I can't find any solution in the docs/ online
You can mount jffs2 partition manually. This partition contains your configuration, so when you mount it, you will be able to edit root password.
Use this command: mount -t jffs2 /dev/mtdblock3 /mnt/. Please note that mtd number may vary in different routers. If there is nothing in /mnt dir after issuing this command, try another mtdblock number.
Then go to /mnt dir and remove /etc/shadow and /etc/passwd files from there to reset root password.
Related
I moved my EFI partition which caused me to enter emergency mode on reboot.
mount -a confirmed fstab had the the UUID of the old partition...it wasn't mounting and that caused emergency mode.
You can't do ANY of the standard remount,rw tricks that normally work... it will always give you an error message the mount doesn't work
Sure, I could start from the USB stick and edit /etc/fstab, but isn't there an easier way?
This question has been around for 10 years and most people answer with a remount as rw, but that always fails.
The clever way is simply mount the / partition on /mnt like:
mount /dev/sda1 /mnt
This mounts it read-write and you just edit /mnt/etc/fstab to change the new UUID for your partition which you can get from either blkid or ls -lha /dev/disk/by-uuid
However, the readonly filesystem will NOT see your changes, so you think you've failed. You'll look at /etc/fstab and it will appear unchanged (at least under btrfs it looks unchanged).
However, when you reboot, you are back in business.
I re-sized my EFI partition down to 260MB, but had to remove it to do that which causes the UUID to change. Just changing the /etc/fstab with the new UUID is all that you need to do so you don't run into trouble. Best to do that when you move the partition, rather than after the fact.
I have RHEL 7.9 installed and here is what I did to edit the fstab after copying from one machine to another using scp.
mount -o remount,rw /dev/sda2 #sda2 is where my root directory is located.
I was then able to open in vim and save the UUID changes I had to make. Worked like a charm.
I've been using this line in /etc/fstab for mounting a storage device to my host:
//url.to-my-storage.com/mystorage /mnt/backup cifs
iocharset=utf8,rw,credentials=/etc/backup-credentials.txt,uid=1000,gid=1000,file_mode=0660,dir_mode=0770
0 0
I was mounting it to another host, and I ran this to protect the files from change through the new host:
chmod -R 444 /mnt/backup
(I tried to protect the storage from writing from this host, which turned out to change the mode of all the storage files)
I assume the missing executable permissions what causing me this:
$ sudo mount -a
mount error(13): Permission denied
Refer to the mount.cifs(8) manual page (e.g. man mount.cifs)
I tried unmounting and mounting again, that didn't help, got the same permission error when using the mount command.
ls the dir shows this:
$ ls -la /mnt/backup
?????????? ? ? ? ? ? backup
HELP !
Dismounting a "Locked Out" Network Drive
To dismount a "locked out" network drive, you can try to force the unmount:
umount -f -t cifs /mnt/backup
If you are having trouble dismounting a drive, make sure that you don't have a console open somewhere where the current working directory (CWD) on the drive which you are trying to dismount, or have a file open in an editor or player somewhere or such.
Properly Mounting a Network Drive
You should add your permissions in your mount options rather than trying to apply them afterwards. You would want to replace these mount options:
rw,file_mode=0660,dir_mode=0770
with
ro
Currently you are mounting your CIFS drive as read-write (rw), giving files read-write permission (file_mode=0660) and directories read-write-execute (dir_mode=0770). Simply mounting the drive as read-only (ro) should suffice. (If you do need to fine tune the file and dir modes, rather use umask.)
I would also advise you to double check whether you are using uid and gid correctly: if the user ID or group ID used gets deleted, that could also lead to problems.
References
https://linux.die.net/man/8/mount
https://en.wikipedia.org/wiki/File_system_permissions
https://oracletechdba.blogspot.com/2017/06/umount-lsof-warning-cant-stat-cifs-file.html
https://stackoverflow.com/a/40527234/171993
Environment is in virtual box,ubuntu 12.04. It has 2 disks, /dev/sda1 and /dev/sdb1 are both ext4 type filesystem.
Since /dev/sdb1 is add after system installed, so I want to mount it manually. I'd try this command:
sudo mount -o user,defaults /dev/sdb1 ~/project
No errors report. Then I get mount info by mount:
/dev/sdb1 on /home/igsrd/project rw,noexec,nosuid,nodev
But when I ls -l to see /home/igsrd I found its permission is still belongs root, so I can't touch anything in it. Why it still belongs root?
I have another machine running ubuntu 12.04,too. I mount another partition with same option will be fine, correct permission(ownership). Are any differences between them?
*nix permissions on a filesystem that supports them natively, e.g. ext4, will be maintained regardless of how it is mounted when using a proper filesystem driver, e.g. the native ext4 driver built into Linux.
Why don't you just (while still root) do this:
chown -R <your-user-name> ~<your-user-name>/project
?
I'd like to mount a remote directory through sshfs on my Debian machine, say at /work. So I added my user to fuse group and I run:
sshfs user#remote.machine.net:/remote/dir /work
and everything works fine. However it would be very nice to have the directory mounted on boot. So I tried the /etc/fstab entry given below:
sshfs#user#remote.machine.net:/remote/dir /work fuse user,_netdev,reconnect,uid=1000,gid=1000,idmap=user 0 0
sshfs asks for password and mounts almost correctly. Almost because my regular user has no access to the mounted directory and when I run ls -la /, I get:
d????????? ? ? ? ? ? work
How can I get it with right permissions trough fstab?
Using option allow_other in /etc/fstab allows other users than the one doing the actual mounting to access the mounted filesystem. When you booting your system and mounting your sshfs, it's done by user root instead of your regular user. When you add allow_other other users than root can access to mount point. File permissions under the mount point still stay the same as they used to be, so if you have a directory with 0700 mask there, it's not accessible by anyone else but root and the owner.
So, instead of
sshfs#user#remote.machine.net:/remote/dir /work fuse user,_netdev,reconnect,uid=1000,gid=1000,idmap=user 0 0
use
sshfs#user#remote.machine.net:/remote/dir /work fuse user,_netdev,reconnect,uid=1000,gid=1000,idmap=user,allow_other 0 0
This did the trick for me at least. I did not test this by booting the system, but instead just issued the mount command as root, then tried to access the mounted sshfs as a regular user.
Also to complement previous answer:
You should prefer the [user]#[host] syntax over the sshfs#[user]#[host] one.
Make sure you allow non-root users to specify the allow_other mount option in /etc/fuse.conf
Make sure you use each sshfs mount at least once manually while root so the host's signature is added to the .ssh/known_hosts file.
$ sudo sshfs [user]#[host]:[remote_path] [local_path] -o allow_other,IdentityFile=[path_to_id_rsa]
REF: https://wiki.archlinux.org/index.php/SSHFS
Also, complementing the accepted answer: there is a need that the user on the target has a right to shell, on target machine: sudo chsh username -> /bin/bash.
I had a user who had /bin/false, and this caused problems.
How can I access and modify /etc/fstab during reboot (maybe accessing to recovery mode) ?
Why this question :
I have updated the virtualbox guests additions in backtrack 5 (as a Virtualbox VM).
I have modified temporary the fstab file to do that but forgotten to turn it back to initial state, like :
mount /dev/cdrom /cdrom
echo "/dev/cdrom /cdrom0 udf,iso9660 defaults,exec 0 0" >> /etc/fstab
So after the guest additions installed, reboot is blocked on mounting this unexisting point.
Thx
edit: maybe to move to serverfault ?
I see two possible solutions to your problem:
Use the recovery mode (if you don't see that in the grub list, edit the default entry and add the word "single" without quotes to the end of the kernel line)
Mount a random .iso file temporarily
Then remove the offending fstab line.
Another option is to boot a Live OS and mount the root filesystem from there. Then you will be able to edit the fstab file.
Once you have the live OS booted
fdisk -l
-find your root partition (usually in the format sda1, sdc1, sda2, etc)
mkdir /mnt/rootfs
mount /dev/sda2 /mnt/rootfs <--sda2 = root partition found in fdisk
cd /mnt/rootfs/etc
-Fstab file should be in there.