General :: Root File System More Users With Different Access Before Mounting?
May 11, 2011
I need to customize linux kernel root file system for embedded linux system. During compile time, for root file system I am able to create different user/group ex: "gnumuzic/Muzic". But I want to give access to group "Muzic" to some folders like /dev/nexig during compile time.
In the boot process of Linux we have the initrd that is a root file system and is mounted before the real root file system become ready to mount. What is the procedure of mounting? What should happen so we can say that file system is mounted? And another little question why we say ¨root¨ file system instead of just file system?
The desktop computer of my two children has a total of three users:
1) The superuser (me) 2) The user 1001 (my elder son) 3) The user 1002 (my younger son)
Both users 1001 and 1002 can not access their files system, and also they can not save any attachments from incoming mails.
What I tried so far: I accessed the file manager as superuser, and went: >Root>Home. Here I right-clicked on the folder User 1001, selected properties, selected the tab 'permissions' and allowed this user to read and write into this folder. I also checked the checkbox ï¿½extend this permission to all subfolders and its contents.
The problem is, when I reboot, everything is 'forgotten' and I am at quadrant zero again.
Eventually I should state that part of the folders are from a backup drive, because the hard disk had to be replaced so, once I re-installed the OS on the new hard drive, I copied the folders from the backup drive into the home folder.
One last question: Is there a good tutorial about permissions?
Is there any way to grant access to non root users to use some commands like reboot and date and some other commands that root user can work with .I tried chmod on their binaries and added them to root group but nothing happened.
I have been trying to use my DS2490 USB to serial device with a Maxim .DG1921G thermocron with owfs. It is supposed to give me access to a virtual file system for the thermocrom without needing to launch owfs as root.
Code: /var/log/messages gives: Feb 8 16:22:45 norman-HP-G56-Notebook-PC kernel: [ 236.140141] usb 5-1: new full speed USB device using ohci_hcd and address 2[code]....
but if ds2490 module is loaded it works when run sudo.It seems from this that it is a lack of permissions to USB but I have tried all the methods on at http://owfs.org/index.php?page=udev etc. to overcome this and a few others but none work.I am running Ubuntu 10.10 kernel 2.6.35-22-generic #33-Ubuntu SMP
I own a particular file on a Linux system. I would like to give 2 groups (accounting, shipping) read access and only read access, and 3 users(Mike, Raj and Wally) write access and only write access. How can I accomplish this?
Recently I was downloading some upgrades in Ubuntu and unfortunately the power to the system got off.
Thereafter on booting it comes to the Grub menu and I'm able to select the OS from the list but if I choose Ubuntu it comes up with a message "General error mounting file system" and the terminal is activated. However, if XP is selected it boots with no issues.
/dev/sda6 is ubuntu installation /dev/sda7 is swap partition
I went through lot of threads over the net and tried fsck, e2fsck and other variations of that command but at the end all I get the message as
it says sda6 is clean but for sda7 it says :
Superblock invalid trying backup blocks.... Bad magic number in super-block while trying to open /dev/sda7 at the end it suggests "u might try running e2fsck with an alternate superblock: e2fsck -b 8193 <device>"
refering some threads here I tried my luck with live CD and the command : sudo e2fsck -C0 -p -f -v /dev/sda7
I made a modification to the /etc/fstab using Ubuntu 10.04 and now it wont boot correctly. I can get the cli but when I enter /etc/fstab and make an edit it says" changing permission of /etc/fstab: read only file system" This is what I get when the system boots:
so if I choose manual I get to the cli and whenever I attempt to edit the file I get the above error. I used another machine and attempted to mount the drive but I get the same error I added notaime option to my fstab by accident so if I choose manual I get to the cli and whenever I attempt to edit the file I get the above error. I used another machine and attempted to mount the drive but I get the same error. I tried
and I get
How can I mount the partition so that I can edit it?
I have an image of an ext3 file system done with dd. I know that the file system is corrupted but I want to try to recover some files. Whatever I dd it again to the original partition or assign the dd image to a loop device, that's what happens:
- dumpe2fs -h gives me a valid ext3 superblock.
- as I try to mount the device read only, it fails with a bad magic number error.
- executing dumpe2fs -h again gives bad magic number error.
- trying debugfs or fsck with backup superblocks fails the same way.
For me it seems that in spite of mounting the device as read-only, mount command do something wrong with the superblock as before the mount the superblock is correct and it's there.
How well is the ext4 new file system mounting compatibility with the older ext3 previous Linux installations ? I refer to Ubuntu 9.04 and the new Fedora 11 which have the option to install with the ext4 file format. Will it be better if I install with the older ext3, so that I will be able to mount all other Linux from each other in a multi-boot system ?
I'm running window xp and unbuntu 10.04. I ran into a problem where I reinstalled unbuntu by erasing old one under CD boot. During installation, it asked me to place files and i placed it in /. Now when I log in as single user (only user or other at login screen) and try to change any system files, it said I don't have permission. I can't change anything or access root file. I try chmod function and it said i don't have permission as well.
I work for a company that makes portable devices running Linux and I was recently asked to make the underlying file system read-only for "security" purposes. Since the distribution is based on LinuxFromScratch, I know that very little writing happens at run time. So, even if the device runs on a usb flash device, I doubt that putting the root file system RO will be that beneficial. I am actually more concerned about a process actually breaking because it cannot open a file in RW mode than a process going rogue and filling the root file system with log files, etc. I'd really like to ear what kind of advantages disadvantages there really is with read-only file-systems.
I have wicd 1.6.1 (bzr-r426) and it is working very good with my root user but with all those which have not the root rights wicd asks for superuser password to connect. I want to avoid this pop-up window to be shown, how can I proceed? I first thought about the sid and gid but it seems that there is no improvements using chmod 4755 and 2755 on the different files involved in.
I find FTP server software confusing in Linux. Using ServU for Windows for an example, all I need to do is to create users via the ServU interface and choose a folder I want that user to have access to and their permissions, and viola, they can connect to that directory, and that directory only.
But in the the land of Linux, it apparently can't be managed this easy. I have a web server with multiple domains, and therefore multiple users need access to their own web root. So with that in mind, what FTP server software should I use (there are plenty out there) and how would I go about to create a user per domain, so that they can log in using FTP to manage their site, and only have access to their own web root, and nothing else?
If there is a general NFS share in the LAN and for example this share has three files - a, b, c is there any way to restrict file access to the root user of one particular host(falcon) in the same LAN environment while the normal users from the same host(falcon) should be able to access the NFS share & files a, b, c.
On a new installation of Linux Red Hat server, I was adding new users from the list using "newusers" command. I did not realize that one of the users was "root" so this is what line I loaded by error (among other users) : root:root:1176:501::/home/circuser:/bin/bash all other users from the list (160 of them) got loaded properly. I still have valid root login that I could use, but I'm not able to log in as root anymore. If I log in as user and then try "su" or "su -" I get error: ": No such file or directory".
I compared /etc/passwd, group and shadow on this server with old one I'm replacing and entry for root looks the same:
root:x:0:0:root:/root:/bin/bash ( in passwd) root:x:0: (in /etc/group) root:$1$OILC.ETm$LkoGprgqqgv6v8oLRUBnf.:15153:0:99999:7::: (in /etc/shadow) - similar to my old server
I am getting an error while booting my linux system: Can't mount root file system.Boot has failed, sleeping forever.OS is Red hat enterprise linux 6, With Intel P4, 1 GB Ram, 120 GB IDE hdd seagate. it was working fine from last 4 days. from today morning this is giving error. only mysql & apache is installed in it. please suggest is there any way to repair the root & boot volumes. waiting for valuable reply.
Is it possible to encrypt the Entire root file system using LUKS.I am currently using Ubuntu 10.4 LUCID.After several hours of Google ,most of the articles were focusing to "Encrypting a drive/removable media ".. My aim is to encrypt whole File system which is currently using.
My Concerns, How to Encrypt a running file system? Will it lead to data loss?
im trying to prepare my partitions for fresh installation. The partition manager didnt list anything with an error message that said:Quote:No root file system is defined. Please correct this from the partitioning menu?This is what Gparted displays Quote:
I have recently experienced a problem that occurred after an automatic update. After the update it said restart system. So I did and proceeded as normal. when after the reboot Firefox suddenly stopped working, crashed and upon clicking it again only a blank box appeared. Then my other apps followed and i soon couldn't do anything so i shut down my computer. Upon restart I got a black screen with tons of text and something around the lines of
mount: mounting /dev on /root/dev failed: No such file or directory mount: mounting / sys/ on root/sys failed: No such file or directory mount: mounting /proc on /root/proc failed: No such file or dirctory
So I rebooted and pressed shift to open that grub thing and booted from an earlier kernel. This time it said checking HD for errors and after booted normally. Everything seemed fine but next day it did it again. Starting with Firefox crashing and then everything else. I again booted from a previous kernel and it worked but upon checking with uname -a it did not list the kernel i chose to boot from. So I decided to upgrade 10.04 to 10.10. This upgraded my kernel and deleted the old ones so i am hoping i am good now.
Information on the net seems very sparse or outdated for how to go about booting to a RAM disk. I need to be be able to boot a PC without a hard drive in it. I want to be able to PXE boot a PC and supply it with a RAM disk image that also contains the contents of the root file system (obviously stripped down enough to keep the file size small and the boot up time fast).What I have gathered so far is that I need to extract the contents of the initrd.img file, add files as necessary, and repackage the initrd.img file. What I get confused on is how to configure the kernel line parameters to tell it to boot to RAM and not the hard drive and how to go about modifying the init script in the initrd.img to not switch to the hard drive for the root file system. I can't find anything on the net that describes concrete steps on how to go about accomplishing all of this. I'm aware of the existence of Live CD's, but I need to be able to boot the PC without relying on a hard drive, CD, or any other external media. It needs to get all of its contents from the PXE boot server and boot to RAM only. I have the PXE boot side configured successfully. Also, putting the root file system on a NFS share is also out of the question.
After upgrading from 10.04 to 10.10 I have had some problems booting my Ubuntu. It all started when restarting after the upgrade, and I got the error;
mount: mounting /dev on /root/dev failed: No such file or directory mount: mounting / sys/ on root/sys failed: No such file or directory mount: mounting /proc on /root/proc failed: No such file or dirctory Target filesystem doesn't have /sbin/init. No init found. Try passing init= boot arg
BusyBox v1.13.3 (Ubuntu 1:188.8.131.52ubuntu11) built-in shell (ash)(initramfs) After searching the Internet, I found a "solution". I just had to boot with a USB stick with the Ubuntu Rescue Remix (the normal Ubuntu USB won't boot either), and i wrote;
sudo fsck /dev/sdb5
Now I could start my Ubuntu again. So whats the problem? If I turn off my computer the normal way, there is no problem, but if I log off, put it into sleep mode, if something happens and I have to turn it off with the button it goes back to the first problem, and I have to reboot it with the USB stick and fix it all over again! If I don't have the USB stick with me, I probably wont be able to use my laptop!
since running update manager on my daughters net running 10.04 netbook on boot up I get the following on the screen
mount: mounting /dev on /root/dev failed: No such file or directory mount: mounting /sys on /root/sys failed: No such file or directory mount: mounting /proc on /root/proc failed: No such file or directory Target filesystem doesnï¿½t have /sbin/init.