100 lines
1.8 KiB
Plaintext
100 lines
1.8 KiB
Plaintext
|
.TH CHDEV 1
|
||
|
|
.SH NAME
|
||
|
|
chdev \- change kernel driver access
|
||
|
|
.SH SYNOPSIS
|
||
|
|
.B chdev
|
||
|
|
[ -nr ] \f2devmask\fP...
|
||
|
|
.SH DESCRIPTION
|
||
|
|
.I Chdev
|
||
|
|
modifies access to kernel drivers for the current
|
||
|
|
process and processes within the same name group
|
||
|
|
(see
|
||
|
|
.IR fork (2)).
|
||
|
|
Access is defined as the ability for a process
|
||
|
|
to walk files and directories served by the driver
|
||
|
|
through its location within '#'. Existing binds
|
||
|
|
of drivers are left unaffected.
|
||
|
|
.PP
|
||
|
|
Access may only be removed; after a specific
|
||
|
|
driver is ejected no further operations can
|
||
|
|
permit access again. Access is inherited by
|
||
|
|
all children of the name group, regardless if the
|
||
|
|
child has elected to receive a clean namespace.
|
||
|
|
.PP
|
||
|
|
.IR Devmask
|
||
|
|
is a string of driver characters. The default
|
||
|
|
behavior is to block access to all but the listed
|
||
|
|
drivers. Flags provide a way to modify this behavior:
|
||
|
|
.TP
|
||
|
|
.B -r
|
||
|
|
Retain access to all but the specified drivers.
|
||
|
|
.TP
|
||
|
|
.B -n
|
||
|
|
Remove access to all drivers.
|
||
|
|
.I Devmask
|
||
|
|
is ignored.
|
||
|
|
.PP
|
||
|
|
Access to some drivers is tied to other
|
||
|
|
related process capabilities:
|
||
|
|
.TP
|
||
|
|
\f2mnt\fP(3)
|
||
|
|
.IP
|
||
|
|
Ability to perform the
|
||
|
|
.IR mount (2)
|
||
|
|
system call, and
|
||
|
|
to post new services to
|
||
|
|
.IR shr (3).
|
||
|
|
.TP
|
||
|
|
\f2pipe\fP(3)
|
||
|
|
.IP
|
||
|
|
Ability to perform the
|
||
|
|
.IR pipe (2)
|
||
|
|
system call.
|
||
|
|
.SH EXAMPLES
|
||
|
|
Permit access to only
|
||
|
|
.IR draw (3),
|
||
|
|
.IR rtc (3),
|
||
|
|
.IR fs (3),
|
||
|
|
and
|
||
|
|
.IR srv (3):
|
||
|
|
.IP
|
||
|
|
.EX
|
||
|
|
chdev irks
|
||
|
|
.EE
|
||
|
|
.PP
|
||
|
|
Remove access to
|
||
|
|
.IR cons (3),
|
||
|
|
.IR rtc (3),
|
||
|
|
.IR audio (3),
|
||
|
|
and
|
||
|
|
.IR proc (3):
|
||
|
|
.IP
|
||
|
|
.EX
|
||
|
|
chdev -r crAp
|
||
|
|
.EE
|
||
|
|
.PP
|
||
|
|
Create a
|
||
|
|
.IR pipe (3)
|
||
|
|
then remove the ability to create more:
|
||
|
|
.IP
|
||
|
|
.EX
|
||
|
|
bind '#|' /n/pipe
|
||
|
|
chdev -r '|'
|
||
|
|
.EE
|
||
|
|
.SH DIAGNOSTICS
|
||
|
|
.I Chdev
|
||
|
|
is implemented through writes to
|
||
|
|
.BR /dev/drivers ,
|
||
|
|
served by
|
||
|
|
.IR cons (3).
|
||
|
|
.SH SOURCE
|
||
|
|
.B /rc/bin/chdev
|
||
|
|
.SH "SEE ALSO"
|
||
|
|
.B /dev/drivers
|
||
|
|
for a list of current drivers.
|
||
|
|
.PP
|
||
|
|
.IR intro (3),
|
||
|
|
.IR cons (3)
|
||
|
|
.SH HISTORY
|
||
|
|
Chdev first appeared in 9front (May, 2022).
|