forgot passwd, cannot login, [rd]init=/bin/sh don't work

Gentlemen, last time I forgot my password and couldn't log into my machine here on my far away rural mountaintop, I ended up digging up an old Debian "potato" CDROM and installing it into some free space on my disk, from which I could edit /etc/passwd and zero out the password. These days that would no longer necessarily work, see man mkfs.ext3 -I.

Didn't work.

OK, I then tried linux-doc-2.6.26/Documentation/kernel-parameters.txt.gz:
rdinit= [KNL]
Format: <full_path>
Run specified binary instead of /init from the ramdisk, used for early userspace startup. See initrd.

So in grub2 I chose "e" to edit, and changed the lines to
linux /boot/vmlinuz-2.6.26-1-686 root=UUID=... rdinit=/bin/sh
initrd /boot/initrd.img-2.6.26-1-686
hit ESC then RET, and alas it was like I didn't type anything at all but just hit RET, booting proceeded as usual, and /proc/cmdline shows that my changes to that command line were thrown away.

The only reason to use a ramdisk during boot is if your kernel doesn't have any support for your root filesystem (unlikely) or for your hardware (much more likely).

If the disk controller on your motherboard isn't too exotic you could probably boot the kernel directly, i.e:
/boot/vmlinuz-2.6.26-1-686 init=/bin/sh root=whatever Note the use of *init* instead of rdinit because you aren't using the initial ramdisk this way.

May or may not work, but it's worth a try.

That's normal behaviour, if you press ESC all your changes are gone.

The solution is not to press ESC, but Ctrl-x instead. There's also a hint about that in the online help below the editor frame.

Niels Böhm

Ah, no wonder. These need rewording:

Use the %C and %C keys to select which entry is highlighted. Press enter to boot the selected OS, 'e' to edit the commands before booting or 'c' for a command-line.

Minimum Emacs-like screen editing is supported. TAB lists available completions. Press C-x ('x' with Ctrl) to boot, C-c ('c' with Ctrl) for a command-line or ESC to return menu.

Here, I have reworded the latter, preserving terseness, and fixing grammar:

Minimum Emacs-like editing is supported. TAB lists available completions. Press C-x ('x' with Ctrl) to boot, C-c for a command-line or ESC to throw away changes and return to menu.

Kindly integrate it into your next version. Thank you.

(There is also a grub screen with its several lines of help text enclosed by "[ ]". Might as well chuck them too.)

By the way, I indeed now could login now without remembering the password. Use
linux /boot/vmlinuz-... root=... rw init=/bin/sh
initrd /boot/initrd.img-...
The key is the "rw init=/bin/sh". (And after editing /etc/passwd to change root's :x: to ::, be sure not to just exit the shell, but hit CTRL-ALT-DEL, else one has to push the reset button.)

Can somebody please integrate my patches? For the parent article and the "grub-install message should mention --recheck" article.

I am a mere "apt-get install" user. I fear if I learn your whole source code system, and finally make an official patch, it too will fall on deaf ears.

As I expect I will only have one patch per three years, please integrate it for me. Thanks.

diff -C 1 menuO*.c menu.c
*** menuORIG.c 2008-12-27 02:42:57.000000000 +0800
--- menu.c 2008-12-27 02:53:49.000000000 +0800
***************
*** 84,87 ****

        Minimum Emacs-like screen editing is supported. TAB lists\n\
!       available completions. Press C-x (\'x\' with Ctrl) to boot,\n\
!       C-c (\'c\' with Ctrl) for a command-line or ESC to return menu.");
      }
--- 84,87 ----
        Minimum Emacs-like screen editing is supported. TAB lists\n\
!       completions. C-x (\'x\' with Ctrl) to boot, C-c for command-line,\n\
!       or ESC to throw away changes and return to menu.");
      }

Please add this somewhere you feel comfortable with in grub.texi.

I looked, but cannot find the right place.

Thank you.

@Chapter Tips
@node Forgot the root password
One place when grub can come in very handy is when one forgot the root password, and hence cannot boot or even shutdown the system. Use @example
linux /boot/vmlinuz-... root=... rw init=/bin/sh
initrd /boot/initrd.img-...
@end example
The key is the "rw init=/bin/sh". (And after editing /etc/passwd to change root's :x: to ::, be sure not to just exit the shell, but hit CTRL-ALT-DEL, else one has to push the reset button.)

Gentlemen, there is a serious usability problem with cmdline.c.

At the very start the user sees the message made by

grub_printf ("\
[ Minimal BASH-like line editing is supported. For the first word, TAB\n\
lists possible command completions. Anywhere else TAB lists possible\n\
device/file completions.%s ]\n\n",

	       nested ? " ESC at any time exits." : "");

The problem is, just let him type "help" just once...

The note about "ESC at any time exits" is now gone from the screen.

He now faces a list of the help commands, with NO "exit" or "quit" choices.

No. Not even the tiniest hint left about how to get back out.

But he is just average, not smart.

He ends up choosing "reboot", the only choice that seems like it will get him BACK.

Therefore, please add
"ESC at any time exits" to the bottom of the help list.

No, I don't know how to make this patch.

You will have to do it for me.

Also note the help list must still fit on one screen after the patch.

Thank you.

Hello,

(I'm not Grub expert)

and I think that better type "sync" to synchronize the buffers.

Also, I'm not sure if this should be in the Grub "Chapter Tips" (because it's half Grub related, half Linux related) (so, maybe would be useful but I wonder if it's the correct place)

What other people thinks?

Carles Pina i Estany		GPG id: 0x17756391
	http://pinux.info

Hello,

Again: I'm not a Grub expert/mantainer, but I have been reading some emails here and I will wear the police hat for this email:

Could you send using diff unified format, with 3 lines of context? (default one)

I think that people here is used to receive this diff's, not the not-unifed format that you sent.

I suggest download from the SVN and use svn diff :-)

Also, and before somebody else will tell to you, could you write a Changelog entry for your patches? (take a look on the current Changelog to know the way that should be written), so you can attach the patch (not in the mail inline) and copy in the email the Changelog entry.

Thanks,

Carles Pina i Estany		GPG id: 0x17756391
	http://pinux.info

2008-12-27 [email protected]

* normal/menu.c: print clearer instructions on the screen

@@ -82,8 +82,8 @@
     {
       grub_printf ("\n\
       Minimum Emacs-like screen editing is supported. TAB lists\n\
-      available completions. Press C-x (\'x\' with Ctrl) to boot,\n\
-      C-c (\'c\' with Ctrl) for a command-line or ESC to return menu.");
+      completions. C-x (\'x\' with Ctrl) to boot, C-c for command-line,\n\
+      or ESC to throw away changes and return to menu.");
     }
   else
     {

"No name needed".

OK, Pavel Roskin's suggestions sound great. I leave this in your hands.

j> OK, Pavel Roskin's suggestions sound great. I leave this in your hands.

However, will these patches I sent this week be used, or
slowly

      forgotten
         ?

I'll track your patches. If everyone comes to a consensus on them in a week I'll commit them to the repo.

I agree with Pavel also that using "Ctrl-<key>" is more descriptive then what is there now.

What other patches where you going to submit like this?

JY> I'll track your patches.
Thanks!
JY> What other patches where you going to submit like this? There is a total of four issues,
[PATCH] grub-install message should mention --recheck [PATCH] menu.c clearer instructions
[semi-PATCH] grub.texi: emergency booting without root passwd cmdline.c: ESC at any time exits: only mentioned once

There won't be more soon as I now boot like a charm.

Committed a variant of this patch into the repository.

Thanks,

Jerone

JY> Committed a variant of this patch into the repository.
OK, thanks. Say, three semi-patches of mine remain to be resolved. Their subjects were:
[PATCH] grub-install message should mention --recheck
[semi-PATCH] grub.texi: emergency booting without root passwd
cmdline.c: ESC at any time exits: only mentioned once

I sent patches etc. last month, Subjects:
[PATCH] grub-install message should mention --recheck [semi-PATCH] grub.texi: emergency booting without root passwd cmdline.c: ESC at any time exits: only mentioned once
but nobody acted on them one way or the other

If you hide your messages to some threads don't expect that hurry people will notice them. Just write a _new_ message and not a reply when starting a _new_ topic.

Personally I can easily mark threads not within my interest area as ignored or mark automatically as read.

This time I'll try to hunt your patches and comment on them if there is something to be done...

First of all it does not work with every Linux distribution and secondly I do not see that we should take any side how to enter to Linux installations without proper authentication...

So you are free to keep information like this on the web, but not as part of official grub distribution...

This is kinda problem for translations anyway. So it would be preferable to have static text there...

What is the overall gain for having nested to control output of that text?

Now the question is, should we provide an exit command? Bash basically supports that so it could be a good idea.

Next week I was going to hunt all the patches I personally missed or had not been commited yet by someone else. Been so busy lately havn't had time. But I did commit one of your patches.

1)[PATCH] grub-install message should mention --recheck
This one really isn't necessary. Kind of agreed with the first commenter. I don't have any strong feeling toward not including it. But it does seem like something that users can easily find when using --help.

2) [semi-PATCH] grub.texi: emergency booting without root passwd This patch isn't completed. Whould need to work on this more

3) cmdline.c: ESC at any time exits: only mentioned once Not sure off head. Will check it though.

Hello,

I'm reading it and I don't see any problem for translation. Should be like:

grub_printf (_("\
[ Minimal BASH-like line editing is supported. For the first word, TAB\n\
lists possible command completions. Anywhere else TAB lists possible\n\
device/file completions.%s ]\n\n"),

	nested ? _(" ESC at any time exits.") : "");

Or I'm wrong?

Carles Pina i Estany		GPG id: 0x17756391
	http://pinux.info

OK, thanks for evaluating them, worthy or not.