IMPACT

  [ pty ]
> Is it self-contained, or does it
> require other mods?

There are certain decisions which anyone installing pty has to make:

1. Should pty run setuid root, or setuid some other user, say ``pty''?
If the latter, then the new user should be added to /etc/passwd, and it
would help to have utmp and wtmp owned by that user. It's generally
simpler to have pty running setuid root. This also lets it chown and
chmod tty device files.

2. pty's INSTALL program copies the binaries to some directory, and sets
up a directory where pty can store session information. Where do those two
directories go? The defaults are /usr/local/ptybin and /usr/local/etc/pty.
pty also maintains four session log files analogous to utmp/wtmp, all in
/usr/local/etc by default.

3. pty comes with some clones of existing programs: biff, lock, mesg,
script, tty, users, wall, who, whoami, write. In many cases these offer
features beyond the standard versions: for instance, if pty has write
permission to utmp, then script (which is just a tiny shell script) will
have a utmp entry, so talk/mail/write/etc. will work. Should they
replace the system versions?

4. pty comes with some programs which belong in rc.local: utmpinit does a
more professional job of utmp initialization than init does; sessnowinit
and scnowinit initialize pty's session log files. Should these be added to
rc.local?

5. pty comes with some programs which belong in daily, weekly, or monthly
cron scripts: wtmprotate, sessrotate, and sclogrotate. On any modern
system, of course, wtmp is rotated anyway, but should sessrotate and
sclogrotate be added to cron scripts? One other program, checkptys,
produces a report on the entire pty subsystem, and can also be run from
cron.

6. pty comes with some other utilities not directly related to session
management. For instance, trecord and tplay make typescripts in a
special format which includes the timing between characters. My tscript
utility works just like script but makes a tapescript which you can play
back later. (This is great for talk conversations and other interactive
sessions.) Should these utilities be part of a user's standard path?
Should pty itself be part of a user's standard path?

7. Should some secure ttys be set aside for pty's use? It's easy to
configure pty so that it only uses (e.g.) tty[u-z]*, which are always
mode 600 root rather than mode 666 root. Or pty can just compete for
insecure ttys like everyone else.