automounting cd-rom & cd-rw devices

Rob nospam at users.sourceforge.net
Sun Mar 28 18:29:43 PST 2004


Matthew Seaman wrote:
> On Sun, Mar 28, 2004 at 05:04:43PM +0900, Rob wrote:
>>
>>What is this sysctl-black-magic about and where is more information?
> 
> 
> You're right that finding which sysctl is required to achieve whatever
> purpose can be tricky.  Finding what sysctls exist is as easy as
> typing 'sysctl -a', but working out what they actually do -- that's a
> different story.  sysctls are generally documented in man pages which
> may or may not have a title related to the name of the sysctl.  Plus
> they are usually documented in the *programming* section of the
> manual, rather than the user or system administration commands
> sections, whose man pages come up by default if there's more than one
> page under the same name.
> 
> Let's take the vfs.usermount sysctl as an example.  That is actually
> documented in mount(2) -- the page describing the mount() (and
> umount()) syscall, not mount(8) -- the program for mounting
> partitions.  If you type 'man mount' you'll get the mount(8) man page
> by default.  However if you type 'man 2 mount' you find this timeless
> wisdom hidden within that page:
> 
>      By default only the super-user may call the mount() function.  This
>      restriction can be removed by setting the sysctl vfs.usermount to a non-
>      zero value.
> 
> How do I know where vfs.usermount is documented? Only by the rather
> unsatisfactory means of grepping the whole collection of man pages:
> 
>     % cd /usr/share/man
>     % find . -name '*.gz' -print | xargs zgrep -l vfs.usermount
> 
> (It would be really nice if the text produced by 'sysctl -d' gave you
> a reference to the man page(s) where the sysctl was documented.)
> 
> There is a project underway to create better documentation for sysctls

Well, at a first glance I found the 'sysctl -ad' to be very incomplete.
Although a few entries here do provide an explanation, too many do not and
vfs.usermount is among them. Completing this table of explanations would
be a good thing to do! Is this related to the project about sysctls docs?

Regards,
Rob.


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