Permissions messed up on the whole disk

[angelofarina]

Ok, I know, I was a fool.
I had the brilliant idea to mess up the permission of my whole disk. I just wondered why I was not allowed to drop a file at the root of my HD. So I right-clicked on the HD icon, run "Get Info", and at the bottom I saw that the permission for "everyone" was "read only". This looked wrong to me, it is my hard disk, I am the only user of this computer, so it looked perfectly sensible to me to set the permission to "read and write" for everyone.
But, not happy of doing just that, I decided to apply this setting also to all the files and folder of my HD....
Result: the system is now completely screwed up, and cannot boot anymore, even in Verbose or Single User mode.
In verbose mode, I see some lines complaining that several PLIST files have "wrong permissions", so they are not processed...

Is there any way to reset the permissions of the whole filesystem (or at least of the critical system files) to their original values, so that the system can, at least, boot up form disk?
I am now booting from an external USB disk, where luckily I did store (a couple of months ago) a copy of my main HD with Carbon Copy Cloner...

Or do I have to re-install OSX LION from scratch?

 

[GGJstudios]

Is there any way to reset the permissions of the whole filesystem (or at least of the critical system files) to their original values, so that the system can, at least, boot up form disk?

Repairing permissions: What you need to know
About Disk Utility's Repair Disk Permissions feature
Repairing Disk Permissions​

 

[angelofarina]

Well, thanks for the pointers, but of course they did not solve my porblem.
I did not explain this in the first post, which was already too long, because it appeared obvious to me that the first thing I attempted, when unable to boot the machine, was to use the "repair permissions" feature of Disk Utility (available on the Recovery Partition).
Although it told me that the permissions were repaired successfully, the system still does not boot.
From what I understand, the "repair permissions" feature of DiskUtility only repairs permissions on Apple's own files, and now the system hangs when attempting to load some PLIST files, which, evidently, were not part of the original installation of OSX...
What I would like more is a trick for telling OSX: "do not bother to check permissions, just accept everything"...
I really HATE those ultraprotective policies which consider everything out-of-standard as suspicious and unreliable...
It is a much worst thing being unable to boot, than booting with some corrupted setting due to a stupid user (like me) who messed up the things...

 

[GGJstudios]

I did not explain this in the first post, which was already too long, because it appeared obvious to me that the first thing I attempted, when unable to boot the machine, was to use the "repair permissions" feature of Disk Utility (available on the Recovery Partition).

It does help if you indicate what things you've tried. Otherwise, there's no way for readers of the thread to know.

How to maximise your MacRumors troubleshooting experience

From what I understand, the "repair permissions" feature of DiskUtility only repairs permissions on Apple's own files

Which is what you asked for:

Is there any way to reset the permissions of ... (or at least of the critical system files)

What I would like more is a trick for telling OSX: "do not bother to check permissions, just accept everything"...

That's not likely, since permissions are integral and crucial in proper Mac OS X functionality.

It looks like a clean install is your best bet.

 

[\-V-/]

Additionally, if you just do a regular install of OS X instead of a clean install... it should leave all your files intact. After that, I would recommend backing your files and doing a clean install.

Since you have a bootable HD of your computer... you could also just back up the files you need and just do a clean install as GG suggested.