minix/minix/commands/DESCRIBE/DESCRIBE.sh
David van Moolenbroek da21d85025 Add PTYFS, Unix98 pseudo terminal support
This patch adds support for Unix98 pseudo terminals, that is,
posix_openpt(3), grantpt(3), unlockpt(3), /dev/ptmx, and /dev/pts/.
The latter is implemented with a new pseudo file system, PTYFS.

In effect, this patch adds secure support for unprivileged pseudo
terminal allocation, allowing programs such as tmux(1) to be used by
non-root users as well.  Test77 has been extended with new tests, and
no longer needs to run as root.

The new functionality is optional.  To revert to the old behavior,
remove the "ptyfs" entry from /etc/fstab.

Technical nodes:

o The reason for not implementing the NetBSD /dev/ptm approach is that
  implementing the corresponding ioctl (TIOCPTMGET) would require
  adding a number of extremely hairy exceptions to VFS, including the
  PTY driver having to create new file descriptors for its own device
  nodes.

o PTYFS is required for Unix98 PTYs in order to avoid that the PTY
  driver has to be aware of old-style PTY naming schemes and even has
  to call chmod(2) on a disk-backed file system.  PTY cannot be its
  own PTYFS since a character driver may currently not also be a file
  system.  However, PTYFS may be subsumed into a DEVFS in the future.

o The Unix98 PTY behavior differs somewhat from NetBSD's, in that
  slave nodes are created on ptyfs only upon the first call to
  grantpt(3).  This approach obviates the need to revoke access as
  part of the grantpt(3) call.

o Shutting down PTY may leave slave nodes on PTYFS, but once PTY is
  restarted, these leftover slave nodes will be removed before they
  create a security risk.  Unmounting PTYFS will make existing PTY
  slaves permanently unavailable, and absence of PTYFS will block
  allocation of new Unix98 PTYs until PTYFS is (re)mounted.

Change-Id: I822b43ba32707c8815fd0f7d5bb7a438f51421c1
2015-06-23 17:43:46 +00:00

256 lines
5.5 KiB
Bash

#!/bin/sh
#
# DESCRIBE 2.2 - Describe the given devices. Author: Kees J. Bot
#
# BUGS
# - Arguments may not contain shell metacharacters.
case $# in
0) flag=; set -$- /dev ;;
*) flag=d ;;
esac
ls -l$flag $* | \
sed -e '/^total/d' \
-e '/^l/d' \
-e '/^[^bc]/s/.* /BAD BAD /' \
-e '/^[bc]/s/.* \([0-9][0-9]*\), *\([0-9][0-9]*\).* /\1 \2 /' \
| {
ex=0 # exit code
while read major minor path
do
case $path in
/*) name=`expr $path : '.*/\\(.*\\)$'`
;;
*) name=$path
esac
dev= des=
case $major in # One of the controllers? What is its controller nr?
3) ctrlr=0 ;;
8) ctrlr=1 ;;
10) ctrlr=2 ;;
12) ctrlr=3 ;;
esac
case $major,$minor in
1,0) des="RAM disk" dev=ram
;;
1,1) des="memory" dev=mem
;;
1,2) des="kernel memory" dev=kmem
;;
1,3) des="null device, data sink" dev=null
;;
1,4) des="boot device loaded from boot image" dev=boot
;;
1,5) des="null byte stream generator" dev=zero
;;
1,6) des="boot image RAM disk" dev=imgrd
;;
1,[789]|1,1[012])
ramdisk=`expr $minor - 7`
des="RAM disk $ramdisk" dev=ram$ramdisk
;;
2,*) drive=`expr $minor % 4`
case `expr $minor - $drive` in
0) des='auto density' dev="fd$drive"
;;
4) des='360k, 5.25"' dev="pc$drive"
;;
8) des='1.2M, 5.25"' dev="at$drive"
;;
12) des='360k in 720k, 5.25"' dev="qd$drive"
;;
16) des='720k, 3.5"' dev="ps$drive"
;;
20) des='360k in 1.2M, 5.25"' dev="pat$drive"
;;
24) des='720k in 1.2M, 5.25"' dev="qh$drive"
;;
28) des='1.44M, 3.5"' dev="PS$drive"
;;
112) des='auto partition 0' dev="fd${drive}p0"
;;
116) des='auto partition 1' dev="fd${drive}p1"
;;
120) des='auto partition 2' dev="fd${drive}p2"
;;
124) des='auto partition 3' dev="fd${drive}p3"
;;
*) dev=BAD
esac
des="floppy drive $drive ($des)"
;;
[38],[05]|[38],[123][05]|1[02],[05]|1[02],[123][05])
drive=`expr $minor / 5`
des="controller $ctrlr disk $drive" dev=c${ctrlr}d${drive}
;;
[38],?|[38],[123]?|1[02],?|1[02],[123]?)
drive=`expr $minor / 5`
par=`expr $minor % 5 - 1`
des="controller $ctrlr disk $drive partition $par"
dev=c${ctrlr}d${drive}p${par}
;;
[38],12[89]|[38],1[3-9]?|[38],2??|1[02],12[89]|1[02],1[3-9]?|1[02],2??)
drive=`expr \\( $minor - 128 \\) / 16`
par=`expr \\( \\( $minor - 128 \\) / 4 \\) % 4`
sub=`expr \\( $minor - 128 \\) % 4`
des="hard disk $drive, partition $par, subpartition $sub"
des="controller $ctrlr disk $drive partition $par slice $sub"
#par=`expr $drive '*' 5 + $par`
dev=c${ctrlr}d${drive}p${par}s${sub}
;;
[38],6[4-9]|[38],7?|1[02],6[4-9]|1[02],7?)
tape=`expr \\( $minor - 64 \\) / 2`
case $minor in
*[02468])
des="controller $ctrlr tape $tape (non-rewinding)"
dev=c${ctrlr}t${tape}n
;;
*[13579])
des="controller $ctrlr tape $tape (rewinding)"
dev=c${ctrlr}t${tape}
esac
;;
4,0) des="console device" dev=console
;;
4,[1-7])des="virtual console $minor" dev=ttyc$minor
;;
4,15) des="diagnostics device" dev=log
;;
4,1[6-9])
line=`expr $minor - 16`
des="serial line $line" dev=tty0$line
;;
4,125) des="video output" dev=video
;;
5,0) des="anonymous tty" dev=tty
;;
6,0) des="line printer, parallel port" dev=lp
;;
7,*)
d=`expr $minor % 8`
n=`expr $minor / 8`
case $d in
0) des="IP stat" dev=ipstat
;;
1) case $name in
psip*)
des="Pseudo IP #$n" dev=psip
;;
*) des="raw ethernet #$n" dev=eth
esac
;;
2) des="raw IP #$n" dev=ip
;;
3) des="TCP/IP #$n" dev=tcp
;;
4) des="UDP #$n" dev=udp
esac
case $d in
[0123])
if [ "$name" = "$dev" ]
then
des="$des (default)"
else
dev=$dev$n
fi
esac
;;
9,0)
des="unix98 pseudoterminal master" dev=ptmx
;;
9,12[89]|9,1[3-8]?|9,19[01])
p=`expr \\( $minor - 128 \\) / 16 | tr '0123' 'pqrs'`
n=`expr $minor % 16`
test $n -ge 10 && n=`expr $n - 10 | tr '012345' 'abcdef'`
des="pseudo tty `expr $minor - 128`" dev=tty$p$n
;;
9,???)
p=`expr \\( $minor - 192 \\) / 16 | tr '0123' 'pqrs'`
n=`expr $minor % 16`
test $n -ge 10 && n=`expr $n - 10 | tr '012345' 'abcdef'`
des="controller of tty$p$n" dev=pty$p$n
;;
11,0)
des="block filter" dev=filter
;;
13,0)
des="audio" dev=audio
;;
14,0)
des="faulty block device driver" dev=fbd
;;
15,0)
des="kernel log" dev=klog
;;
16,0)
des="pseudo random number generator" dev=urandom
;;
17,0)
des="hello" dev=hello
;;
18,0)
des="UNIX domain socket" dev=uds
;;
5[6-9],0|6[0-3],0)
drive=`expr $major - 56`
des="vnode disk $drive" dev=vnd$drive
;;
5[6-9],[1-4]|6[0-3],[1-4])
drive=`expr $major - 56`
par=`expr $minor - 1`
des="vnode disk $drive partition $par" dev=vnd${drive}p${par}
;;
5[6-9],12[89]|5[6-9],13[0-9]|5[6-9],14[0-3]|6[0-3],12[89]|5[6-9],13[0-9]|5[6-9],14[0-3])
drive=`expr $major - 56`
par=`expr \\( \\( $minor - 128 \\) / 4 \\) % 4`
sub=`expr \\( $minor - 128 \\) % 4`
des="vnode disk $drive partition $par slice $sub"
dev=vnd${drive}p${par}s${sub}
;;
64,0)
des="keyboard input multiplexer"
dev=kbdmux
;;
64,[1-4])
n=`expr $minor - 1`
des="keyboard input $n"
dev=kbd$n
;;
64,64)
des="mouse input multiplexer"
dev=mousemux
;;
64,6[5-8])
n=`expr $minor - 65`
des="mouse input $n"
dev=mouse$n
;;
BAD,BAD)
des= dev=
;;
*) dev=BAD
esac
case $name:$dev in
*:)
echo "$path: not a device" >&2
ex=1
;;
*:*BAD*)
echo "$path: cannot describe: major=$major, minor=$minor" >&2
ex=1
;;
$dev:*)
echo "$path: $des"
;;
*:*) echo "$path: nonstandard name for $dev: $des"
esac
done
exit $ex
}