Re: [PATCH] Syscalls: reboot: Add options to the reboot syscall toremount filesystems ro

[Linus Torvalds]

On Thu, Mar 3, 2011 at 9:45 AM, Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> How many mounted filesystems do you have that it's so hard to keep track of?

Btw, /proc/mounts will track them for you even if you don't have a
'mount' binary that does.

Parsing that is pretty trivial. If you have spaces or special
characters in your pathnames (you may control the mount paths, you may
not - I have no idea), you'll need to be able to handle the escape
format (\oct). But other than that, it's literally just

 - read all of /proc/mounts into a buffer

 - for each line, split by space, and you'll have the directory name
right there in the second field

 - do the unescaping ("\oct" -> character) if needed. It's good
practice. Test it.

 - just do a read-only remount on it.

All done. No kernel changes necessary. It just works.

                            Linus
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