(1) Reject zero-length strings for CTLTYPE_INT, _UINT, _LONG,
_ULONG. Do not silently convert to 0.
(2) When converting CTLTYPE_INT, _UINT, _LONG, and _ULONG, check the
end pointer generated by strtol() and strtoul() rather than
discarding it. Reject the string if either none of the string
was useful for conversion to an integer, or if there was
trailing garbage.
I.e., we will not allow you to set a numeric sysctl to a value unless
we can completely convert the string argument to a numeric value.
I tripped over this when I put the following in /etc/sysctl.conf:
kern.maxfiles="4000"
Ouch.
by Sheldon.
For a detailed description look at the commit log for sysctl.c
rev.1.42 -- i do not think it is appropriate to put the full
description in this manpage, and the "boot" and "loader" manpages
where this description might go are also missing a description of
a number of similar variables, so i think this it is ok to limit
documentation to this now, and update it later when I (or someone
else) have a chance to revise "boot" and "loader".
machdep.guessed_bootdev, and add code to sysctl to parse its value
and give a (not necessarily correct) name to the device we booted
from (the main motivation for this code is to use the info in the
PicoBSD boot scripts, and the impact on the kernel is minimal).
NOTE: the information available in bootdev is not always reliable,
so you should not trust it too much. The parsing code is the same
as in boot2.c, and cannot cover all cases -- as it is, it seems to
work fine with floppies and IDE disks recognised by the BIOS. It
_should_ work as well with SCSI disks recognised by the BIOS.
Booting from a CDROM in floppy emulation will return /dev/fd0 (because
this is what the BIOS tells us).
Booting off the network (e.g. with etherboot) leaves bootdev unset so
the value will be printed as "invalid (0xffffffff)".
Finally, this feature might go away at some point, hopefully when we
have a more reliable way to get the same information.
MFC-after: 5 days
a special file on the command line, eg:
sysctl kern.dumpdev=/dev/ad1s1b
In parse(), when a value is given for a CTLTYPE_QUAD variable,
newval and newsize erroneously fail to be set because of an early
"break".
show_var() contains code that duplicates the functionality of the
oidfmt() function.
PR: 33151, 33150
Submitted by: Thomas Quinot <thomas@cuivre.fr.eu.org>
variables. Use the -d flag in sysctl(8) to see this information.
Possible extensions to sysctl:
+ report variables that do not have a description
+ given a name, report the oid it maps to.
Note to developers: have a look at your code, there are a number of
variables which do not have a description.
Note to developers: do we want this in 4.5 ? It is a very small change
and very useful for documentation purposes.
Suggested by: Orion Hodson
