 |
Hummingbird Computing
|
|
|
|
Removing Root Password
from SGI Systems Problem: The root password has been lost or forgotten for your SGI workstation. Assumption: You know the password for the PROM Monitor or it has not been set. If the PROM Monitor password has been set and you do not know it, refer to the appropriate system reference manual for instructions on how to disable the PROM Monitor password. On many SGI workstations adding or moving a jumper on the motherboard accomplishes this. Throughout the text are comments that
will explain what you are doing or what is about to happen as a result of
executing a command.
Software Installation
Tools General Information
The IRIX operating system and all the
optional software products are released as a set of CDROMs. The IRIX 5.X and 6.X
release CDROMs contain the following:
- sashARCS
The ARCS sash. The 5.0 and 5.0.1 CDROMs contain only sashARCS, while the 5.1.1 and later CDROM contains the sash images for all the different CPU types.
Copies of other sash, fx, and ide
images are maintained in /stand for the other CPU types on the
5.1.1 and later CDROM.
The Standalone Tools are,
sash, fx, and the mini-root. The mini-root, with it’s
Install Utility (inst), is used to build a new operating
system or update (add to) an existing system with additional
software images. The mini-root loads into and
runs out of the system disk swap partition. The mini-root, because
it resides in the swap partition, and has the special directories
of /root and /root/usr, in which it mounts the root
and user partitions. Begin Actual
Procedure. STEP 1: Booting the Mini-Root and Starting the Install Tool (inst) You must be in the PROM Monitor in
order to boot the mini-root from the CDROM.
We will start the process by selecting
choice #2: Install System Software. The PROM Monitor will prompt you,
asking you if the load device is a local or remote device. The PROM Monitor will load
sash from the
volume header of
the CDROM, and then sash will load the mini-root
from partition
7 of the CDROM. Once the mini-root is loaded, the Installation Tool
(inst) is started,
which you will immediately exit by starting a mini-root shell.
Once in the shell, you will
use vi to edit the /etc/passwd file. The load from the CDROM will take
several minutes, during which time dots are output to
the screen to inform you that the load is progressing. Let’s load the mini-root.
After inst
creates a filesystem in partition 6 and mounts it at /root/usr,
it displays it’s Main Menu. *****************WARNING*************** When the mini-root is started, the system disks
partition table is
modified to allow the install tool to function correctly. When you
quit the install tool, the partition table
will be set back to its
correct values by inst, therefore, while in the
mini-root shell, do not
forget how you got there and inadvertently attempt a reboot
or shutdown.
You must return to
inst and select
quit to insure that
the partition table is returned to its normal settings. Also, when you are normally
in inst and want to
quit, you would select quit and inst would ask you if you wanted to
reboot the system.
Since there is no root filesystem, the reboot would fail. Inst
knows this and would
not allow the reboot and would instead output an
error message informing you that the root filesystem was not usable. STEP 2: Starting a Mini-Root Shell. Let’s exit the install tool by starting
a mini-root shell.
Now that we are in a mini-root shell,
let’s use the ls command and look at the mini-root top
level directory (/). STEP 3: Editing the /etc/passwd
contents to remove the password for root. We will use the vi screen-oriented (visual) display editor to edit the contents of the passwd file. Remember that when mini root loaded no .profile or .cshrc files contain path statements or other use environmental variables were loaded. This means that you will need to provide the absolute path to vi and the passwd file. Open the passwd file using vi.
Here is a sample /etc/passwd file which
this command opens: root:q.mJzTnu8icF.:0:10:superuser:/:/bin/csh
bill:6k/7KCFRPNVXg,z/:508:10:& The
Cat:/usr2/bill:/bin/csh + john:+@documentation:no-login:
+::::Guest nobody:*:-2:-2::/dev/null:/dev/null
In this example, there are specific
entries for users root and bill, to assure that they can log in even when
the system is running stand-alone or when the NIS is not running. The user
bill has 63 weeks of maximum password aging and 1 week of minimum password
aging. Programs that use the
GECOS field replace the & with `Bill'. The user john has his password
entry in the NIS incorporated without change; anyone in the netgroup
documentation has their password field disabled, and anyone else is able
to log in with their usual password, shell, and home directory, but with a
GECOS field of Guest. The user nobody cannot log in and is used by the
exportfs(1M) command. To remove the password for root you want to delete the characters between the first and second : in the line starting with the word root. To do this use the space bar to move the cursor over the first character to be deleted. If you go to far you can use the back space key to the cursor back one character at a time. Once you reach the first character delete it using the x key continue this until all of the characters between the two : are deleted. After you have finished deleting all of the characters between the two colons, press the Esc key to make sure that you are not in an edit or delete mode. The next step is to save the modified file and exit vi. Use the following commands to accomplish this.
If you delete too many characters you can undelete a single character using the u key or alternatively quit the file leaving it unchanged by typing :q! without first typing :w!, which writes out you changes to the disk file. STEP 4: Returning to the Install
Tool. If you remember,
we started the mini-root shell (using sh) while we were in
the install tool (inst). I mentioned (at
that time) that the install tool modifies the partition table
to suit its own needs, and the current state of the partition table
is not compatible with IRIX. You must return to inst and select quit, allowing inst to restore the volume header to the state that it was in before inst was started. Follow the procedure on the next page to exit the mini-root and terminate inst. Return to inst
using exit.
2.
When inst is entered, execute quit.
3.
Answer yes, allowing inst to clean up the volume header.
| ||||||||||||||||||||||||||||||||||||||||||||||||||||
Send mail to jokeefe@hummingbirdcomp.com
with questions or comments about this web site. |
