Usenet 1993 July/InfoMagic USENET CD-ROM July 1993.ISO/sources/unix/volume22/pty/part02

Internet Message Format | 1990-10-09 | 54.0 KB

Subject:  v23i032:  Run a program under a pty session, Part02/06
Newsgroups: comp.sources.unix
Approved: [e-mail]
X-Checksum-Snefru: 6fe1a084 64d83c14 ac39c37e bf52d9f3

Submitted-by: Dan Bernstein <[e-mail]>
Posting-number: Volume 23, Issue 32
Archive-name: pty/part02

#! /bin/sh
# This is a shell archive.  Remove anything before this line, then feed it
# into a shell via "sh file" or similar.  To overwrite existing files,
# type "sh file -c".
# The tool that generated this appeared in the comp.sources.unix newsgroup;
# send mail to [e-mail] if you want that tool.
# Contents:  INSTALLREADABLE master.c pty.c
# Wrapped by [e-mail] on Wed Oct 10 10:11:37 1990
PATH=/bin:/usr/bin:/usr/ucb ; export PATH
echo If this archive is complete, you will see the following message:
echo '          "shar: End of archive 2 (of 6)."'
if test -f 'INSTALLREADABLE' -a "${1}" != "-c" ; then
  echo shar: Will not clobber existing file \"'INSTALLREADABLE'\"
else
  echo shar: Extracting \"'INSTALLREADABLE'\" \(22621 characters\)
  sed "s/^X//" >'INSTALLREADABLE' <<'END_OF_FILE'
XThis is a typescript of INSTALL on a Sun 4 running SunOS 4.0.3.
XI've inserted some further comments at spots where INSTALL might give
Xdifferent results on different machines.
X
X
X
XHi, and welcome to the pty install script.
Xpty is a program for managing pseudo-terminals.
X
XI'm not actually going to install anything.
XI'll just guide you through what has to be done,
Xfrom compiling through installation.
X
XOne advantage of this hands-off philosophy is that
Xyou can kill and restart this script at any time.
XYou may prefer to read through INSTALLREADABLE,
Xwhich has the same information.
X
XIn the first part of this script, I'll lead you through configuration.
XFor the moment, don't actually change anything in your system. Just
Xalternate between reading this script and fooling around with the
XMakefile, and I'll remind you later, after compilation, of what has
Xto be changed elsewhere.
X
XI need the following programs: echo, tr [-d], man, sed [-n], grep, test.
X
X----- Press return to continue.
X
XThe first versions of pty were designed on a BSD 4.2-based system.
XDuring May 1990 pty 3.0 was written completely from scratch,
Xon a BSD 4.3-based system. It has been thoroughly tested on
Xseveral BSD 4.3-based systems, tested with a few Makefile changes
Xon several BSD 4.2-based systems, and run on at least one mutant.
X
XIf you make it through installation and testing and get pty running,
Xplease send a note to the author, Dan Bernstein, on the Internet
Xat [e-mail]. Let him know your computer model, OS version, and
Xwhat changes you had to make. If you have any trouble, please also get
Xin touch with the author. If you have a different kind of system with
Xpseudo-terminal support that could use a pty port, the author would
Xlove to hear about it.
X
XOne note: Like all software, pty comes without warranty, to the extent
Xpermitted by applicable law. Use it at your own risk.
X
X----- Press return to continue.
X
XI assume that you don't want to make any major changes
Xto your computer just to take advantage of pty's capabilities.
XYou might not even have a privileged account, for all I know.
X
XThe first major decision you have to make is what privileges to give pty.
XObviously if you don't have privileges then pty won't either;
Xthis is Case UN.
X
X----- Press return to continue.
X
XThere are several good reasons for giving programs privileges.
XMost importantly, privileged programs can precisely control access
Xto a shared resource. pty supports an interactive user list in
X/etc/utmp, a login-logout record in /usr/adm/wtmp, and controlled
Xaccess to the pseudo-terminal files themselves, including security and
Xmode changing. None of these are possible if pty isn't setuid.
X
XIf your system has a lot more tty security than usual, you probably
Xwon't be able to run pty without privileges. (However, if your system
Xhas a lot more tty security than usual, it's almost certainly running
Xpty anyway.)
X
X----- Press return to continue.
X
XIf you do want pty to have privileges, you have to decide between
Xsetting up pty as root (Case ROOT) or as some other user, say ``pty''
X(Case PTY). Staying away from root has the advantage that problems
Xcan't possibly destroy all security in one blow. However, root has
Xseveral advantages, mainly because of BSD limitations: 1. A process
Xcan't change ownership of a file between its euid and uid. Only root
Xcan change ownership. It shouldn't be necessary to change ownership
Xof ptys anyway, but that's what many programs assume. 2. MAXUPRC in
X<sys/param.h> limits the number of processes under a given *effective*
Xuid. This absolutely idiotic behavior is a serious problem for programs
Xsetuid to anything other than root. pty tries to work around this
Xproblem, but there are no true solutions. 3. Despite the documentation
Xin kill(2), many machines don't allow non-root processes to send
XCONT to children with a different uid. Unlike almost all other programs,
Xpty sensibly handles its child stopping and restarting; but this won't
Xwork on those machines if pty isn't root.
X
XYou should decide now between Case ROOT and Case PTY.
X
X----- Press return to continue.
X
XWhether you've decided on ROOT, PTY, or UN,
Xnow is the time to check the security of the entire pty package.
XIt'd be difficult for anything to slip through the checks by the
Xauthor, testers, and source group moderator, but you should take
Xat least a moment to look for your pet security peeves.
X
XA couple of security notes: The only open(,O_CREAT) in pty is in
Xmaster.c, at the top of master(), of a file with a very restricted
Xform constructed from the filename of a /dev/ttyxx. There are no
Xcreat()s. The only bind() is in sock.c's pty_readsock(), which is
Xcalled only from master.c's master() to create a socket with a
Xsimilarly restricted name. (fnsty is changed in sigler but not in
Xmaster.) The only exec() is in slave.c, after a forced setreuid()
Xto a uid that is only set to getuid(). unlink(), mkdir(), and rename()
Xare only used with restricted pathnames.
X
X----- Press return to continue.
X
XIn Case PTY, you have to set up a new uid, say ``pty'' (or whatever
Xusername you want). pty should not allow logins. Its password should
Xbe an asterisk; its home directory should be /nonexistent; its shell
Xshould be /bin/true. In other words, the only access to user pty
Xshould be through these setuid programs.
X
XIn any privileged case you should have group tty,
Xwhich most BSD 4.3 systems have as gid 4.
X
XRunning $ ttygroup="`sed -n 's/^tty:[^:]*:\(.*\):.*/\1/p' < /etc/group`" ...
X
XI see that you have a tty group, 4 as usual. Good.
X
X[Note: Under SunOS 4.0.3, ttygroup comes out to 4. On systems where it
Xcomes out to nothing at all, you have to add the line tty:4:*:root to
X/etc/group. On systems where the tty group is something other than 4,
Xjust remember it.]
X
X----- Press return to continue.
X
XNext, we're going to drudge through the config.h file.
X
XIn Cases ROOT or PTY, you have to set up a system-wide directory
Xfor storing information about pty sessions. (A session is a program
Xstuck under a pty that you can disconnect and reconnect.) Users can
Xget around this directory, storing the information in ~/.pty and
Xrevoking any privileges, with pty -xS; you can even make this default
Xby setting flagxsetuid = 0 in globals.c. However, a single system-wide
Xdirectory is safer.
X
XAnyway, that directory, PTYDIR, should be mode 0700, owner root in case
XROOT or pty in case PTY, group irrelevant. PTYDIR is defined in config.h
Xas /usr/etc/pty by default; if you choose a different directory, add
X-DPTYDIR=\"/what/ever/dir/ect/ory\" to CCOPTS in the Makefile.
X
XIn Case UN, you may want to set up a directory ~/PTY inside your home
Xdirectory, and set PTYDIR to that; you may want to set flagxsetuid = 0
Xin globals.c; or you may want to just type -xS to pty all the time. I
Xrecommend the first strategy.
X
X----- Press return to continue.
X
XNext come pseudo-terminal pathnames. I assume that your ptys are
Xlabelled as /dev/ptyxx and /dev/ttyxx, where xx is any two-letter
Xextension. pty can support any initial strings instead of these,
Xbut some of the utilities have /dev/tty hardcoded, and lots of other
Xprograms running around assume those names. If you're desperate,
Xdefine DEVMTY and DEVSTY in the Makefile, and figure out what has to
Xbe changed in util/*. (Sorry.)
X
X----- Press return to continue.
X
XThe extension is traditionally [p-za-o][0-9a-f]. The first letter of the
Xsecond string is special: if /dev/ttyq0 doesn't exist, for example, then
Xnone of /dev/ttyq[0-9a-f] will be used. (That's called a pty bank.)
X
XYou can change those strings by defining, e.g., PTY1=\"ABCDEFG\" or
XPTY2=\"02468abfq\" in the Makefile. You have at least four choices here:
X1. Give pty its own, new, banks of new pseudo-terminals with weird bank
Xnames not including a through z, and define PTY1 appropriately. pty will
Xonly use those new ptys, and older programs will just use the old ptys.
XThis may require reconfiguring your system for the larger number of
Xterminals. 2. Give pty some new banks, and take out some old ones to
Xmake up for it. 3. Give pty a chunk of the old banks. 4. Give pty all
Xthe old banks.
X
XNote that pty searches randomly through PTY1 and PTY2 by default; for
Xefficiency, PTY1 really should reflect exactly the pty banks you have.
X
X----- Press return to continue.
X
XSo now you've decided on new ptys, or set aside some or all of your
Xold ptys, and changed PTY1 and PTY2 appropriately. Because BSD gives a
Xprocess very little control over its controlling terminal, pty has to
Xpass a terminal name explicitly when it reconnects. If any of your tty
X(not just pseudo-tty!) filenames are longer than 30 characters, you have
Xto set -DTTYNAMELEN=60 (or whatever) in the Makefile.
X
X----- Press return to continue.
X
X/etc/utmp has traditionally listed all users logged on.
XThis nebulous concept has evolved through the years; given the way
Xthat most programs use utmp, utmp is probably better defined as a
Xlist of all interactive sessions. Anyway, pty supports this file,
Xand will make an entry in it when given -xu. If you have a different
Xfile, add -DPTYUTMP_FILE=\"/foo/bar/utmp\" to DEFINES in the Makefile.
X
XNote that /etc/utmp is unprotected (mode 666) on Suns. This was Sun's
Xattempt to let unprivileged programs manage the file. Unforunately, this
Xerror in judgment opens up a huge security hole, which even on
Xsingle-user machines is an invitation to make mistakes. I advise you to
Xmake /etc/utmp owned by root in Case ROOT or pty in Case PTY, mode 644.
XThere aren't many unprivileged programs that don't understand the
Xpty interface; people on non-Suns have survived so far, and there's
Xno reason for you to keep subscribing to an insecure model of resource
Xsharing.
X
X----- Press return to continue.
X
XAlthough pty will put an entry into utmp, it doesn't really support
Xthe remote-host field. There is no logical association between sessions
Xand connections; why should a login require a pty, and why should a
Xsession only stick around for one connection? So pty just puts "pty" in
Xthe host field. You can change this with -DPTYUTMP_HOST=\"foo\"; you may
Xeven want to make PTY_UTMPHOST call a function that you define.
X
X(Similar comments apply to PTYWTMP_HOST. There are also PTYUTMP_SWHOST
Xand PTYWTMP_SWHOST, defaults PTYUTMP_HOST and "pty-sessuser"
Xrespectively; see util/sessuser.1 for more information.)
X
X----- Press return to continue.
X
X/usr/adm/wtmp has traditionally recorded all logins, logouts, reboots,
Xftp sessions, and various other interesting events. (The entry for a
Xline in utmp is the last entry for that line in wtmp.) pty supports wtmp
Xfully, in the same way as utmp. You should make wtmp mode 644, owner
Xroot or pty as appropriate. Change PTYWTMP_FILE if /usr/adm/wtmp is
Xsomewhere else.
X
X----- Press return to continue.
X
XYou can turn off utmp support by uncommenting the NO_UTMP line in
Xconfig.h. (Just delete the initial /*.) You can also turn off support
Xfor wtmp, disconnectable sessions, or changing pseudo-terminal file
Xownership; just uncomment the appropriate line. You can force use of
Xeach of these features by defining MUST_UTMP, etc., in the same way.
X
XNote that the usual login programs do their own wtmp management, and
Xmany accounting programs incorrectly equate session time with connect
Xtime, so users will rarely want wtmp. As more programs appear using the
Xpty interface, and as login programs start using a more logical system
Xfor accounting, MUST_WTMP may become an appropriate way to monitor
Xpseudo-terminal usage. For the moment, I do not advise setting any NO
Xor MUST.
X
X----- Press return to continue.
X
Xpty subscribes (not very willingly) to the BSD 4.3 model of pty
Xprotection, with a few twists. All ptys are under group tty, at all
Xtimes; if you don't have a tty group, all ptys should be under some
Xother protected group at all times. Anyway, pty will change the group of
Xeach pseudo-terminal file to PTYGROUP, default 4, under -xc.
X
X
XSince you already have a tty group, gid 4, you're fine.
X
X[Note: If your tty group is something other than 4, add -DPTYGROUP=6 (or
Xwhatever) to the Makefile.]
X
X
X(Under Case UN, don't worry about all this group stuff. Just leave
XPTYGROUP alone.)
X
X----- Press return to continue.
X
XUnder -xc, pty changes the pseudo-terminal owner to the current real
Xuid. The fact that terminals need to be in the file hierarchy reflects a
Xserious failure in the BSD terminal model; but anyway, many programs
Xexpect to be able to fool around with /dev/tty. After pty is done with
Xthe terminal, it sets the owner back to its effective uid. You can
Xmodify this behavior by changing PTYOWNER from euid to something else.
X
XUnder Case UN, PTYOWNER is irrelevant.
X
X----- Press return to continue.
X
XWhile a tty is unused, BSD systems traditionally leave it unprotected.
XUnfortunately, this leaves some huge security holes. Here's one of
Xthe biggest advantages of a privileged pty manager: unused ttys don't
Xhave to be left open for any random program to use. After it's done
Xwith a pseudo-terminal, pty changes it to mode UNUSEDPTYMODE, default
X0600. (This is another case of a poor model for kludging pty support
Xinto unprivileged programs. If you haven't set up separate pty banks
Xfor pty, and you really want to allow unprivileged access to unused
Xptys, try mode 0660 and make those other programs setgid to tty.)
X
XA tty that someone's using can be in many different modes. Typically
XUSEDPTYMODE should be 0600, which means user-only access, messages off,
Xbiff off. If you really, really, really want to make the mistake of
Xhaving messages or biff on by default, try 0620, 0700, or 0720. Note
Xthat the world protection should always be 0: the point of the tty group
Xis that only setgid-tty programs can access ttys.
X
XAs usual, you can't do anything about these in Case UN.
X
X----- Press return to continue.
X
XNow we're past generic configuration and down to your system's
Xnitty-gritty.
X
XFor purity, pty has SIGRET_TYPE, default int, as the type returned by a
Xsignal handler. On Suns and ANSI-compliant machines, you should define
XSIGRET_TYPE=void. Then you can admire the lint -haxc *.c output.
X
X----- Press return to continue.
X
XOUTBUFSIZE, default 16384, is the size of the buffer pty keeps between
Xthe incoming data and the pseudo-tty, and between the pseudo-tty and the
Xoutgoing data. If you want to spare less than 32K per pty just for
Xbuffer space, feel free to change this.
X
X----- Press return to continue.
X
XGENERIC is another concession to ANSI taste. GENERIC * should be a
Xpointer type that any other pointer can be safely converted to and back;
XGENERIC is char by default, but on newer machines can be set to void.
XAs it'll be at least five years before ANSI manages to outlaw char *,
Xand as void * is often invalid, I advise you to leave GENERIC alone.
X
X----- Press return to continue.
X
Xpty attempts to forward window-size changes transparently. It also
Xsupports the auxiliary characters structure, which lets you type a
Xsingle character to get system and tty status.
X
XRunning $ man 4 tty | sed 's///g' | grep -s winsize
XReformatting page.  Wait... done
X
XI see you don't have window sizes.
XYou'll have to comment out #define TTY_WINSIZE in config.h.
X(This may be inaccurate on Suns; try grep winsize /usr/include/sys/tt*.h.)
X
X[Note: As a matter of fact, the test is inaccurate under SunOS 4.0.3,
Xwhich does have window sizes. If you have window sizes, you don't have
Xto do anything.]
X
XRunning $ man 4 tty | sed 's///g' | grep -s auxchars
XReformatting page.  Wait... done
X
XI see you don't have auxiliary characters.
X
X[Note: This is the usual. If you have auxiliary characters and want pty
Xto understand them, uncomment #define TTY_AUXCHARS in config.h.]
X
X----- Press return to continue.
X
Xpty also puts siginterrupt() and usleep() to good use in working
Xaround BSD limitations. Without siginterrupt(), there is absolutely
Xno way to get per-process non-blocking I/O, so pty may block when it
Xdoesn't have to (namely, when it has N bytes to write to the output,
Xthe output is a pipe with M bytes of space, and N > M > 0). If you
Xdefine SIGINTERRUPT (as default), pty will take some extra effort to
Xnever, ever, ever block when it doesn't have to.
X
XAt one point, pty pauses to kludge around a common bug in UNIX-domain
Xsockets. With usleep() it will pause much more briefly. This makes
Xreconnects much faster.
X
XRunning $ man siginterrupt | sed 's///g' | grep -s siginterrupt
XReformatting page.  Wait... done
X
XI see you have siginterrupt(). Good.
X
XWeird, are you BSD 4.3?
X
X[Note: Without siginterrupt(), you have to comment out #define
XSIGINTERRUPT in config.h.]
X
XRunning $ man usleep | sed 's///g' | grep -s usleep
XReformatting page.  Wait... done
X
XI see you have usleep(). Good.
X
X[Note: Without usleep(), you have to comment out #define USLEEP in
Xconfig.h.]
X
X----- Press return to continue.
X
XFinally (almost done with configuration!), we have to make sure that you
Xhave UNIX-domain sockets, and check whether you have file descriptor
Xpassing.
X
XRunning $ test -r /usr/include/sys/un.h
X
XI see you have UNIX-domain sockets. Good.
X
X[Note: If <sys/un.h> isn't there, you probably don't have UNIX-domain
Xsockets, which means you can't have disconnectable sessions. Define
XNO_UNIXSOCKS in config.h.]
X
XRunning $ man recvmsg | sed 's///g' | grep -s rights
XReformatting page.  Wait... done
X
XI see you have file descriptor passing. Good. (Your fd passing may be
Xbuggy, as it's a relatively new, powerful, and rarely exploited
Xfeature. If you have trouble, try defining NO_FDPASSING.)
X
X[Note: If there isn't a recvmsg() man page mentioning access rights, you
Xprobably don't have file descriptor passing. This isn't a disaster,
Xthough it means that reconnected sessions will be as slow as they are in
Xprograms other than pty. Define NO_FDPASSING.]
X
X----- Press return to continue.
X
XWhew! We've finally made it through configuration. If you want, try
Xrunning lint -haxc *.c or whatever your favorite code checker is; the
Xlint here gives some bogus errors about correct char * casts, an error
Xbecause the SIG_IGN definition is unportable, and a couple of bzero
Xcomplaints because FD_ZERO isn't defined very well.
X
XIf you're on an old system without FD_ZERO, FD_SET, and FD_ISSET in
X<sys/types.h>, I recommend you upgrade. Try copying file.h.old to file.h
X(the original version is in file.h.new).
X
XWe're nearly at the end. Change CC and CCOPTS in the Makefile for any
Xlast-minute additions; if you're worried, change -s to -g for debugging.
XNow compile! % (date; make) >>& Makelog & and come back to this script.
X
X----- Press return to continue.
X
XWhile the program is compiling, let's start providing some support.
X(If the compile finishes or has an error, just ignore it for the
Xmoment.) These are some real changes, so watch out!
X
XFirst---in Case PTY only!---make a new uid, pty, not allowing logins.
X
X/etc/passwd:  pty:*:whatever:4:::/bin/true
X
X----- Press return to continue.
X
XSecond, make sure you have a tty group set up.
X
X/etc/group:  tty:*:4:root
X
X----- Press return to continue.
X
XThird, make PTYDIR.
X
XROOT: # mkdir /usr/etc/pty; chmod 700 /usr/etc/pty
XPTY: # mkdir /usr/etc/pty; chown pty /usr/etc/pty; chmod 700 /usr/etc/pty
XUN: % mkdir ~/PTY; chmod 700 ~/PTY
X
X----- Press return to continue.
X
XFourth, make sure you have all the pseudo-terminal files set up and
Xappropriately configured.
X
XChange each of them to group tty.
X
XChange each of them to owner pty in case PTY or root in case ROOT.
X
XChange each of them to mode UNUSEDPTYMODE (0600).
X
X----- Press return to continue.
X
XFifth, make sure /etc/utmp and /usr/adm/wtmp exist, owned by root in
XCase ROOT or pty in Case PTY, each mode 644. (In Case UN, you probably
Xwant to be working on a Sun with its insecure /etc/utmp, so that pty can
Xtake advantage of it. Sigh.)
X
X----- Press return to continue.
X
XSixth, I advise that you make a special directory /usr/local/ptybin for
Xpty and its associated utilities, with symbolic links in /usr/local.
XThis choice isn't too important, but it's easier if you know a
Xplace to put programs.
X
X----- Press return to continue.
X
XOkay. You've done about all that can be done before compilation
Xfinishes, so go do something else.
X
X----- Press return to continue.
X
XThe compile should be done now. If all went well, the make should have
Xexited normally, Makelog should show no errors, and you should have an
Xexecutable pty program sitting in this directory. Unfortunately, life
Xisn't always so generous. Here are a few of the more common errors.
X
XThe loader complains about missing getopt(), optarg, and optind: These
Xare all in the getopt library, available in the early volumes of
Xcomp.sources.unix. If you use GNU getopt, please make sure you
Xunderstand the implications of its license.
X
XThe loader complains about missing FD_ZERO, FD_SET, and FD_ISSET: Try
Xcopying file.h.old to file.h and recompiling. If the compiler gives
Xvarious further errors related to these macros, uncomment the
Xcommented-out lines in file.h.old, copy to file.h, and try once again.
X
Xbcopy() isn't defined: In pty.h, change bcopy(src,dst,num) to
Xmemcpy(dst,src,num). (Note the order.) Try again.
X
XIf you still can't get the code to compile, let the author know.
X
X----- Press return to continue.
X
XNext, compile the utilities. There isn't much to say about them;
Xthey're all public domain, some of them clones of or improvements
Xover standard utilities, some of them clones with special features to
Xwork with pty, some of them entirely new programs for pty's new
Xfeatures. Just glance at the top of util/Makefile; then
X% cd util; (date; make) >>& Makelog & and wait.
X
XWarning: The pty session directory is hardcoded in util/sessutil.c.
XIf you have changed PTYDIR, check through sessutil.c carefully.
X
X----- Press return to continue.
X
XSo now you should have some executables sitting around collecting dust.
XIn Cases ROOT and PTY, put {pty,biff,disconnect,mesg,reconnect,sesskill,
Xsesslist,sessname,sessuser} into a system-wide directory, owner root or
Xpty, mode 4755. Put wall and write into the same place, group tty, mode
X2755. Put {condom,excloff,exclon,last,lock,script,script.tidy,sess,tiocsti,
Xtty,u,who,xdisconnect,xreconnect,xsesskill,xsesslist,xsessname,xsessuser}
Xinto the same place, mode 755. Make absolutely sure none of the shell
Xscripts are setuid.
X
XIn Case UN, just put all the programs somewhere in your PATH.
X
XThat's it! Try running TESTS now.
X
X(Two other things you have to do at some point: move your old script,
Xbiff, mesg, and so on to script.old, biff.old, mesg.old, etc., with
Xsymbolic links to the new versions in their place; and move the old
X/usr/man/{script,biff,mesg,...}.1 somewhere else, copy all the *.1
Xhere to /usr/man/man1, and run /etc/catman.)
END_OF_FILE
  if test 22621 -ne `wc -c <'INSTALLREADABLE'`; then
    echo shar: \"'INSTALLREADABLE'\" unpacked with wrong size!
  fi
  # end of 'INSTALLREADABLE'
fi
if test -f 'master.c' -a "${1}" != "-c" ; then
  echo shar: Will not clobber existing file \"'master.c'\"
else
  echo shar: Extracting \"'master.c'\" \(18086 characters\)
  sed "s/^X//" >'master.c' <<'END_OF_FILE'
X/* Copyright 1990, Daniel J. Bernstein. All rights reserved. */
X
X#include <sys/types.h>
X#include <sys/time.h>
X#include <sys/resource.h>
X#include <sys/wait.h>
X#include <stdio.h>
X#include "err.h"
X#include "config.h"
X#include "pty.h"
X#include "master.h"
X#include "sig.h"
X#include "tty.h"
X#include "file.h"
X#include "sock.h"
X#include "logs.h"
X#include "misc.h"
X
Xstatic char fnre[20];
X
Xstatic char fnsess[20];
Xstatic int fdsess;
X
Xstatic char *glfnsty;
X
Xstatic char soutbuf[OUTBUFSIZE];
Xstatic char sptybuf[OUTBUFSIZE];
X
Xstatic struct ttymodes tmowinpty;
Xstatic struct ttymodes tmowintty;
X
Xstatic char *outbuf = soutbuf;
Xstatic int outbufsiz = OUTBUFSIZE;
Xstatic int outbuflen = 0;
Xstatic char *ptybuf = sptybuf;
Xstatic int ptybufsiz = OUTBUFSIZE;
Xstatic int ptybuflen = 0;
X
Xstatic int flagconnected = 1; /* 0: disconnected. 2: idling for stop. */
X                              /* 3: idling for stop but child is dead. */
Xstatic int flagchild = 1; /* 0: dead. 2: stopped. */
Xstatic int childsig; /* signal that stopped/killed child */
Xstatic int flagsigler = 1; /* 0: dead. */
Xstatic int siglerpid; /* only defined if flagconnected */
Xstatic int slavepid;
X
Xstatic int flagqwinch = 0;
X
Xstatic void quickdeath(i)
Xint i;
X{
X /* All exits from master() go through here. */
X if (flagsession) (void) unlink(fnsess);
X if (flagxchown)
X   (void) fchown(fdsty,PTYOWNER,PTYGROUP);
X (void) fchmod(fdsty,UNUSEDPTYMODE);
X date = now();
X if (flagxutmp)
X   if (utmp(glfnsty + PTYUTMP_OFFSET,"","",date) == -1)
X     ; /* too bad. */
X if (flagxwtmp)
X   if (wtmp(glfnsty + PTYWTMP_OFFSET,"","",date) == -1)
X     ; /* too bad. */
X fatal(i);
X}
X
Xstatic void death(i)
Xint i;
X{
X (void) kill(siglerpid,SIGTERM);
X /* XXX: should wait while flagsigler */
X quickdeath(i);
X}
X
X/*ARGSUSED*/
Xstatic void sig_force(i)
Xsig_num i;
X{
X /* Forced death, presumably from the sesskill program. */
X sig_ignore(SIGCHLD);
X /* XXX: Should we test for !flagchild here? sesskill does. */
X flagchild = 0;
X quickdeath(SIGCHLD);
X}
X
X/*ARGSUSED*/
Xstatic void sig_usr2(i)
Xsig_num i;
X{
X if (flagsession)
X  {
X   int newuid = uid;
X   char newsuid[10];
X   char foo[100];
X
X   /* XXX: We should have some error recovery here! */
X
X   (void) lseek(fdsess,(long) 0,0);
X   (void) read(fdsess,(char *) &newuid,sizeof(int));
X   (void) sprintf(newsuid,"%d",newuid);
X
X   (void) chdir("..");
X   if (chdir(newsuid) == -1)
X    {
X     (void) mkdir(newsuid,0700);
X     (void) chdir(newsuid);
X    }
X
X   (void) sprintf(foo,"../%d/%s",uid,fnsess);
X   (void) rename(foo,fnsess);
X
X   (void) sprintf(foo,"../%d/%s",uid,fnre);
X   (void) rename(foo,fnre); /* in case we're already disconnected */
X
X   uid = newuid;
X   (void) setreuid(uid,euid);
X   setusername();
X
X   if (flagxutmp)
X     if (utmp(glfnsty + PTYUTMP_OFFSET,username,PTYUTMP_SWHOST,date) == -1)
X       ; /* too bad. */
X   if (flagxwtmp)
X     if (wtmp(glfnsty + PTYWTMP_OFFSET,username,PTYWTMP_SWHOST,date) == -1)
X       ; /* too bad. */
X   if (flagsigler)
X     (void) kill(siglerpid,SIGUSR2);
X  }
X}
X
X/*ARGSUSED*/
Xstatic void sig_pipe(i)
Xsig_num i;
X{
X flagsigler = 0; /* XXX: is this appropriate? race? */
X /* Will end up giving child HUP. */
X}
X
X/*ARGSUSED*/
Xstatic void sig_chld(i)
Xsig_num i;
X{
X union wait w;
X
X if (wait3(&w,WNOHANG | WUNTRACED,(struct rusage *) 0) <= 0)
X   return; /* why'd we get the CHLD? it must have stopped & restarted? */
X
X if (w.w_stopval == WSTOPPED)
X  {
X   childsig = w.w_stopsig;
X   flagchild = 2;
X  }
X else
X  {
X   childsig = w.w_termsig; /* can't do much with this */
X   flagchild = 0;
X  }
X}
X
X/*ARGSUSED*/
Xstatic void sig_term(i)
Xsig_num i;
X{
X flagsigler = 0;
X}
X
X/* If we have made it to being master, we should never get TTIN or TTOU, */
X/* except possibly while restarting after a stop (e.g., if the user puts */
X/* us back into the background). But we let the signaller handle putting */
X/* the tty modes back before restarting us, so we should never, ever, */
X/* ever get a TTIN or TTOU. If the user is messing around and we do get */
X/* a TTIN or TTOU, we'll just pretend the child died and hope we get */
X/* around to telling the signaller about it. */
X
X/*ARGSUSED*/
Xstatic void sig_ttin(i)
Xsig_num i;
X{
X if (flagchild)
X  {
X   childsig = SIGTTIN;
X   flagchild = 2;
X  }
X}
X
X/*ARGSUSED*/
Xstatic void sig_ttou(i)
Xsig_num i;
X{
X if (flagchild)
X  {
X   childsig = SIGTTOU;
X   flagchild = 2;
X  }
X}
X
X/*ARGSUSED*/
Xstatic void sig_tstp(i)
Xsig_num i;
X{
X if (flagchild)
X  {
X   childsig = SIGCONT;
X   flagchild = 2;
X  }
X}
X
X/* Most job-control shells (including csh) behave absolutely miserably. */
X/* (Well, that goes without saying.) In particular, rather than sending */
X/* a CONT to every one of their children in the process group, they feel */
X/* a need to kill the entire process group. Grrrr. Because of this, we */
X/* are forced to use the nonintuitive USR1 to communicate CONT, and ignore */
X/* CONT entirely. Anyway, read cont as usr1 where necessary. */
X
X/* We can only get USR1 from the signaller (or from us after reconnect). */
X/* By convention, the signaller handles setting the tty modes back to */
X/* chartty, even though we handled restoring the modes before stop. */
X
X/*ARGSUSED*/
Xstatic void sig_cont(i)
Xsig_num i;
X{
X if (flagchild)
X  {
X   flagchild = 1;
X   (void) kill(slavepid,SIGCONT);
X   (void) kill(pid,SIGWINCH);
X  }
X if (flagconnected == 3)
X   flagconnected = 1; /* XXX: should be internal to master() */
X (void) setpgrp(0,pgrp);
X}
X
X/* If it weren't for WINCH, which must be in the master if NO_FDPASSING, */
X/* and for the stupid conventions surrounding a process's control tty, */
X/* then all mention of fdtty could disappear from master. This would */
X/* slightly complicate the signaller's T{STP,TIN,TOU} handling but make */
X/* reconnect a lot simpler. Sigh. */
X
X/*ARGSUSED*/
Xstatic void sig_winch(i)
Xsig_num i;
X{
X int pg;
X
X flagqwinch = 0;
X#ifdef TTY_WINDOWS
X/* An unfortunate but slight race: Another handler could change the pgrp */
X/* if the child suddenly stops and we're queued for delivery. So we have */
X/* to change it back. */
X pg = getpgrp(0);
X (void) setpgrp(0,pgrp);
X if (!flagsigler)
X   flagqwinch = 1;
X else
X   if (tty_getmodes(fdsty,&tmopty) == 0)
X     if (tty_getmodes(fdtty,&tmowintty) == 0)
X      {
X       tty_copymodes(&tmowinpty,&tmopty);
X       tty_copywin(&tmowinpty,&tmowintty);
X       (void) tty_modifymodes(fdsty,&tmowinpty,&tmopty);
X      }
X (void) setpgrp(0,pg);
X#endif
X}
X
Xstatic int disconnect(fnsty)
Xchar *fnsty;
X{
X if (fdtty != -1)
X  {
X   (void) tty_dissoc(fdtty); /* must succeed */
X   (void) close(fdtty);
X   fdtty = -1;
X  }
X if (fdpass != -1)
X  {
X   /* We used to write the dot to fdpass here. It's in sigler now, to */
X   /* prevent a race condition. */
X   (void) close(fdpass);
X   fdpass = -1;
X  }
X if (fdin != -1)
X  {
X   (void) close(fdin);
X   fdin = -1;
X  }
X if (fdout != -1)
X  {
X   (void) close(fdout);
X   fdout = -1;
X  }
X if (fdre != -1)
X  {
X   (void) close(fdre);
X   fdre = -1;
X  }
X
X fdre = pty_readsock(fnsty,fnre);
X if (fdre == -1)
X   return -1; /* damn. */
X return 0;
X}
X
Xstatic int reconnect()
X{
X int t;
X char buf[1];
X char fntty[TTYNAMELEN]; /* sigh */
X int flags = 0;
X
X t = pty_acceptsock(fdre);
X (void) close(fdre);
X fdre = t;
X if (fdre == -1)
X   return -1;
X
X#define VCF (void) close(fdre)
X#define BONK(xxx,yyy) if ((xxx) == -1) { VCF; return -1; } else (yyy);
X
X/* What about fd 2 for warnings & errors? No, master doesn't use them. */
X
X/* Must have: in, out, siglerpid, pgrp, flagjobctrl. 1, 2, 16, 32, 256. */
X/* Except if NO_FDPASSING: just flagjobctrl in that case. */
X/* If fdtty, must have also tmochartty, tmotty, fntty. 8: 64, 128, 1024. */
X/* Finally, fdpass is independent of all the rest. */
X
X/* CHANGE: With fdpass, fdin and fdout are irrelevant. */
X
X if (pty_sendint(fdre,'p',&pid) == -1)
X  {
X   VCF;
X   return -1;
X  }
X
X while (pty_getch(fdre,buf) == 0)
X   switch(buf[0])
X    {
X#ifdef NO_FDPASSING
X     case 's': BONK(pty_putgetstr(fdre,'s',fntty),flags |= 8) break;
X#else
X     case '0': BONK(pty_putgetfd(fdre,'0',&fdin),flags |= 1) break;
X     case '1': BONK(pty_putgetfd(fdre,'1',&fdout),flags |= 2) break;
X     case 'f': BONK(pty_putgetfd(fdre,'f',&fdpass),flags |= 4) break;
X     case 't': BONK(pty_putgetfd(fdre,'t',&fdtty),flags |= 8) break;
X     case 's': BONK(pty_putgetstr(fdre,'s',fntty),flags |= 1024) break;
X#endif
X     case 'p': BONK(pty_putgetint(fdre,'p',&siglerpid),flags |= 16) break;
X     case 'g': BONK(pty_putgetint(fdre,'g',&pgrp),flags |= 32) break;
X     case 'c': BONK(pty_putgettty(fdre,'c',&tmochartty),flags |= 64) break;
X     case 'n': BONK(pty_putgettty(fdre,'n',&tmotty),flags |= 128) break;
X     case 'j': BONK(pty_putgetint(fdre,'j',&flagjobctrl),flags |= 256) break;
X#ifdef NO_FDPASSING
X     case ' ': if ((flags & 256) != 256) { VCF; return -1; }
X#else
X     case ' ': if (flags & 4) flags |= 3;
X           if ((flags & 307) != 307) { VCF; return -1; }
X           if (flags & 8) if ((flags & 1024) != 1024) { VCF; return -1; }
X#endif
X           if (flags & 8) if ((flags & 192) != 192) { VCF; return -1; }
X
X#ifdef NO_FDPASSING
X               if ((fdtty = open(fntty,O_RDWR)) == -1)
X         return -1;
X           if ((fdin = dup(fdre)) == -1)
X        {
X         (void) close(fdtty);
X         fdtty = -1;
X         return -1;
X        }
X           if ((fdout = dup(fdre)) == -1)
X        {
X         (void) close(fdtty);
X         fdtty = -1;
X         (void) close(fdout);
X         fdout = -1;
X         return -1;
X        }
X#endif
X           VCF; /* yahoo! */
X           (void) close(open(fntty,O_RDWR));
X           /* XXX: do we really have to reattach? */
X           /* I wish there were no concept of controlling tty. */
X           /* Instead, an ioctl on /dev/tty (i.e., fd 3) would */
X           /* return a session identifier. */
X
X           if (fdpass != -1)
X        {
X         if (pty_sendint(fdpass,'G',&siglerpid) == -1)
X           return -1;
X           /* XXX: death(1) might be more intuitive. Then */
X           /* again, it may also be much more destructive. */
X         if (pty_sendfd(fdpass,'m',&fdmty) == -1)
X           return -1;
X         if (pty_sendfd(fdpass,'s',&fdsty) == -1)
X           return -1;
X        }
X
X           /* So that we can disconnect again, we have to reset the */
X           /* siglerpid in fdsess. That done, we've totally severed */
X           /* our previous link to a connection. */
X               (void) lseek(fdsess,(long) sizeof(int),0);
X               (void) write(fdsess,(char *) &siglerpid,sizeof(int));
X
X           flagsigler = 1;
X           (void) setpgrp(0,pgrp);
X           (void) kill(pid,SIGUSR1); /* grrrr */
X           return 0;
X     default: (void) pty_putch(fdre," "); break;
X    }
X VCF;
X return -1;
X}
X
Xstruct timeval instant = { 0, 0 };
X
Xvoid master(fnsty,child)
Xchar *fnsty;
Xint child;
X{
X fd_set rfds;
X fd_set wfds;
X int fdnum;
X int r;
X
X /* XXX: is it a race for child to set pty modes? */
X
X /* Note that we don't close fdsty. */
X
X siglerpid = getppid();
X slavepid = child;
X pid = getpid();
X glfnsty = fnsty;
X
X if (flagsession)
X  {
X   /* Security note: This is the only file we actually create, */
X   /* not counting the reconnect socket. */
X   (void) sprintf(fnsess,"sess.%s",fnsty + sizeof(DEVSTY) - 3);
X   fdsess = open(fnsess,O_RDWR | O_CREAT | O_TRUNC,0600);
X   (void) write(fdsess,(char *) &uid,sizeof(int));
X   (void) write(fdsess,(char *) &siglerpid,sizeof(int));
X   (void) write(fdsess,(char *) &pid,sizeof(int));
X   (void) write(fdsess,(char *) &slavepid,sizeof(int));
X   /* We'll never actually bother closing fdsess. Who cares? */
X  }
X
X sig_ignore(SIGURG);
X sig_ignore(SIGIO);
X sig_ignore(SIGHUP);
X sig_ignore(SIGQUIT);
X sig_ignore(SIGINT);
X sig_sethandler(SIGXCPU,sig_force); sig_handle(SIGXCPU);
X sig_ignore(SIGXFSZ);
X sig_ignore(SIGPROF);
X sig_ignore(SIGVTALRM);
X
X sig_default(SIGEMT); /* XXX: really dump? */
X sig_default(SIGIOT);
X sig_default(SIGTRAP);
X sig_default(SIGSYS);
X sig_default(SIGFPE);
X sig_default(SIGILL);
X sig_default(SIGSEGV);
X
X sig_default(SIGSTOP);
X
X sig_sethandler(SIGTTIN,sig_ttin); sig_handle(SIGTTIN);
X sig_sethandler(SIGTTOU,sig_ttou); sig_handle(SIGTTOU);
X sig_sethandler(SIGTSTP,sig_tstp); sig_handle(SIGTSTP);
X sig_sethandler(SIGUSR1,sig_cont); sig_handle(SIGUSR1);
X sig_ignore(SIGCONT); /* grrrr. see explanation above sig_cont. */
X sig_sethandler(SIGPIPE,sig_pipe); sig_handle(SIGPIPE);
X
X sig_sethandler(SIGCHLD,sig_chld); sig_handle(SIGCHLD);
X
X sig_sethandler(SIGTERM,sig_term); sig_handle(SIGTERM);
X sig_sethandler(SIGWINCH,sig_winch); sig_handle(SIGWINCH);
X
X sig_sethandler(SIGUSR2,sig_usr2); sig_handle(SIGUSR2);
X
X if (fdpass != -1)
X  {
X   if (pty_sendint(fdpass,'G',&siglerpid) == -1)
X     death(1);
X   if (pty_sendfd(fdpass,'m',&fdmty) == -1)
X     death(1);
X   if (pty_sendfd(fdpass,'s',&fdsty) == -1)
X     death(1);
X  }
X
X#define SET_FDNUM fdnum = fdin; if (fdout > fdnum) fdnum = fdout; \
Xif (fdmty > fdnum) fdnum = fdmty; fdnum++;
X
X SET_FDNUM
X
X if (fdpass == -1)
X   (void) fcntl(fdmty,F_SETFL,FNDELAY);
X   /* If it doesn't work, too bad. */
X
X#ifdef SIGINTERRUPT
X sig_interrupt();
X#endif
X
X for (;;)
X  {
X   /* Stage 1: Mangle internal states. This could be made into a */
X   /* critical section, but there's no point. */
X
X   if ((flagconnected == 2) && (flagchild != 2))
X     flagconnected = 1 + 2 * (flagchild == 0);
X   if ((flagconnected != 0) && (flagsigler == 0))
X    {
X     flagconnected = 0;
X     if (flagsession)
X      {
X       (void) kill(siglerpid,SIGTERM);
X#ifdef NO_SESSION
X       ; /* impossible */
X#else
X       if (disconnect(fnsty) == -1)
X     quickdeath(1); /* XXX: sigh */
X       if (fdnum <= fdre)
X     fdnum = fdre + 1;
X#endif
X      }
X    }
X
X   /* Stage 2: Prepare fds, and select(). */
X
X   FD_ZERO(&rfds);
X   FD_ZERO(&wfds);
X
X   if ((fdpass == -1) && (outbuflen < outbufsiz))
X     FD_SET(fdmty,&rfds);
X   if ((fdpass == -1) && ptybuflen)
X     FD_SET(fdmty,&wfds);
X   if ((fdpass == -1)
X     &&(ptybuflen < ptybufsiz) && (flagsigler == 1)
X     &&(flagconnected == 1) && (flagchild == 1))
X     FD_SET(fdin,&rfds);
X   if ((fdpass == -1)
X     &&(outbuflen) && (flagsigler == 1) && (flagconnected == 1))
X     FD_SET(fdout,&wfds);
X
X   if (flagsession && (flagconnected == 0))
X     FD_SET(fdre,&rfds);
X
X   /* The times to flush buffers: when the child has stopped and we're */
X   /* connected; when the child has died and we're connected; when the */
X   /* signaller has died and we don't support sessions. */
X   if (((flagconnected == 1) && (flagchild != 1))
X     ||((flagconnected == 0) && (flagsession == 0)))
X     r = select(fdnum,&rfds,&wfds,(fd_set *) 0,&instant);
X   else
X     r = select(fdnum,&rfds,&wfds,(fd_set *) 0,(struct timeval *) 0);
X
X
X   /* Stage 3: Interpret the results and handle special cases. */
X
X   if (r <= 0)
X     if (r == -1)
X       switch(errno)
X        {
X         case EBADF: death(1);
X                     break;
X         case EINTR: break; /* fine. */
X         case EINVAL: break; /* impossible. */
X         default: break; /* say what? */
X        }
X     else /* r is 0 */
X      {
X       if (flagconnected == 1) /* flagchild is 0 or 2 */
X     if (flagchild == 0)
X       break; /* That's it! Child died, and we're outta here! */
X     else
X      { /* done with flush, time to stop sigler & idle */
X       if (flagjobctrl)
X        {
X         /* As usual, if we don't have a tty, tmotty == tmochartty
X        and it won't matter that fdtty is undefined. */
X         (void) setpgrp(0,pgrp);
X           if (tty_modifymodes(fdtty,&tmotty,&tmochartty) == -1)
X           ; /* XXX: what to do? */
X         (void) setpgrp(0,pid);
X         switch(childsig)
X          {
X           case SIGSTOP: (void) kill(siglerpid,SIGSTOP); break;
X           case SIGTTOU: (void) kill(siglerpid,SIGTTOU); break;
X           case SIGTTIN: (void) kill(siglerpid,SIGTTIN); break;
X           case SIGTSTP: (void) kill(siglerpid,SIGTSTP); break;
X           case SIGCONT: break; /* special case---see sig_tstp */
X           default: (void) kill(siglerpid,SIGSTOP); break;
X          }
X         flagconnected = 2;
X        }
X      }
X       else if (flagconnected == 0) /* non-session, sigler dead */
X     break; /* Giving pty pgrp a HUP, ho hum */
X     /* Most pgrp-based killing would be more logically done */
X     /* one process at a time, i.e., we should give our child */
X     /* a signal specially. But nobody else does, so we won't. */
X      }
X   else
X    {
X#ifndef NO_SESSION
X     if (flagconnected == 0)
X       if (FD_ISSET(fdre,&rfds))
X     if (reconnect() == -1)
X      {
X       if (disconnect(fnsty) == -1)
X         quickdeath(1); /* sigh */
X           if (fdnum <= fdre)
X         fdnum = fdre + 1;
X          }
X     else
X      {
X       flagconnected = 1; /* yay! */
X       SET_FDNUM
X       continue; /* XXX */
X      }
X#endif
X
X
X   /* Stage 4: Do normal I/O. */
X
X#ifdef SIGINTERRUPT
X     sig_startring(); /* blocking? never heard of it */
X#endif
X
X     if (FD_ISSET(fdin,&rfds))
X      {
X       /* ptybuflen must be smaller than ptybufsiz. */
X       r = read(fdin,ptybuf + ptybuflen,ptybufsiz - ptybuflen);
X       if (r == -1)
X     switch(errno)
X      {
X       case EINTR: case EWOULDBLOCK: break; /* fine */
X       default: death(1);
X      }
X       else if (r == 0) /* EOF */
X    {
X     ; /* XXX: there's no way to pass an EOF */
X    }
X       else
X     ptybuflen += r;
X      }
X     if (FD_ISSET(fdmty,&rfds))
X      {
X       /* outbuflen must be smaller than outbufsiz. */
X       r = read(fdmty,outbuf + outbuflen,outbufsiz - outbuflen);
X       if (r == -1)
X     switch(errno)
X      {
X       case EINTR: case EWOULDBLOCK: break; /* fine */
X       default: death(1);
X      }
X       else if (r == 0) /* EOF */
X    {
X     ; /* This can't happen. The slave can't pass an EOF. */
X     /* XXX: Should we close fdout anyway? */
X    }
X       else
X     outbuflen += r;
X      }
X     if (FD_ISSET(fdout,&wfds))
X      {
X       r = write(fdout,outbuf,outbuflen);
X       if (r == -1)
X     switch(errno)
X      {
X       case EINTR: case EWOULDBLOCK: break; /* fine */
X       default: death(1);
X      }
X       else if (r == 0) /* ? */
X     ; /* impossible */
X       else if (r == outbuflen)
X     outbuflen = 0;
X       else
X    {
X     outbuflen -= r;
X         copy(outbuf,outbuf + r,outbuflen);
X    }
X      }
X     if (FD_ISSET(fdmty,&wfds))
X      {
X       r = write(fdmty,ptybuf,ptybuflen);
X       if (r == -1)
X     switch(errno)
X      {
X       case EINTR: case EWOULDBLOCK: break; /* fine */
X       default: death(1);
X      }
X       else if (r == 0) /* ? */
X     ; /* impossible */
X       else if (r == ptybuflen)
X     ptybuflen = 0;
X       else
X    {
X     ptybuflen -= r;
X         copy(ptybuf,ptybuf + r,ptybuflen);
X    }
X      }
X
X#ifdef SIGINTERRUPT
X     sig_stopring();
X#endif
X    }
X  }
X
X death(0);
X}
END_OF_FILE
  if test 18086 -ne `wc -c <'master.c'`; then
    echo shar: \"'master.c'\" unpacked with wrong size!
  fi
  # end of 'master.c'
fi
if test -f 'pty.c' -a "${1}" != "-c" ; then
  echo shar: Will not clobber existing file \"'pty.c'\"
else
  echo shar: Extracting \"'pty.c'\" \(10563 characters\)
  sed "s/^X//" >'pty.c' <<'END_OF_FILE'
X/* Copyright 1990, Daniel J. Bernstein. All rights reserved. */
X
X/*
Xpty.c: run a program under a pty session
X*/
X
X#include <stdio.h>
Xextern unsigned short getuid(); /* grrrr */
Xextern unsigned short geteuid(); /* grrrr */
X#include "config.h"
X#include "getopt.h"
X#include "err.h"
X#include "pty.h"
X#include "tty.h"
X#include "texts.h"
X#include "sig.h"
X#include "sigler.h"
X#include "master.h"
X#include "slave.h"
X#include "file.h"
X#include "logs.h"
X#include "misc.h"
X
Xint flagpcbreak = 0; /* -pc, character-at-a-time */
Xint flagpnew = 1; /* -pd, new line discipline---traditionally off to start */
Xint flagpecho = 1; /* -pe, echo characters */
Xint flagpcrmod = 1; /* -pn, munge carriage returns */
Xint flagpraw = 0; /* -pr, raw mode */
Xint flagpcrt = 1; /* -ps, screen */
X
Xgetfreepty(fnmty,fnsty,pty1,pty2)
Xregister char fnmty[sizeof(DEVMTY)];
Xregister char fnsty[sizeof(DEVSTY)];
Xregister char pty1[sizeof(PTY1)];
Xregister char pty2[sizeof(PTY2)];
X{
X register char *c1;
X register char *c2;
X register char *c1start; /* for ``random'' pty searching */
X register char *c2start;
X int e;
X
X if (flagxrandom)
X  {
X   c1start = pty1 + (pid % (sizeof(PTY1) - 1));
X   c2start = pty2 + ((pid + date) % (sizeof(PTY2) - 1));
X  }
X else
X  {
X   c1start = pty1;
X   c2start = pty2;
X  }
X
X c1 = c1start;
X do
X  {
X   fnmty[sizeof(DEVMTY) - 3] = *c1;
X   fnmty[sizeof(DEVMTY) - 2] = pty2[0];
X   if (!access(fnmty,F_OK))
X    {
X     c2 = c2start;
X     fnsty[sizeof(DEVSTY) - 3] = *c1;
X     fnmty[sizeof(DEVMTY) - 2] = fnsty[sizeof(DEVSTY) - 2] = *c2;
X     do
X      {
X#ifdef DESPERATE_ALARMS
X       sig_startring();
X#endif
X
X/* Some other process could come along and mess up our test by opening */
X/* the master side before we do. But in that case they'll get the pty */
X/* anyway, and we'll move on to another possibility without comment. */
X       if (flagxchkopen)
X    {
X#ifdef DONT_NDELAY
X         fdsty = open(fnsty,O_RDWR);
X#else
X         fdsty = open(fnsty,O_RDWR | O_NDELAY);
X#endif
X         e = errno;
X         fdmty = open(fnmty,O_RDWR);
X    }
X       else
X    {
X         fdmty = open(fnmty,O_RDWR);
X         fdsty = open(fnsty,O_RDWR);
X     e = errno;
X    }
X
X#ifdef DESPERATE_ALARMS
X       sig_stopring();
X#endif
X
X       if (fdmty != -1)
X    {
X     if (flagxskipopen && (fdsty != -1))
X       warnerr2("pty: warning: slave %s still in use\n",fnsty);
X     else
X      {
X       if ((fdsty == -1) && (e != EINTR) && (e != EWOULDBLOCK))
X         fatalerr2p(6,"pty: fatal: slave %s unopenable",fnsty,e);
X       if (flagxchkopen)
X         if (fdsty == -1)
X          {
X           fdsty = open(fnsty,O_RDWR);
X           e = errno;
X          }
X         else
X           warnerr2("pty: warning: slave %s still in use\n",fnsty);
X       if (fdsty == -1)
X         fatalerr2p(6,"pty: fatal: slave %s unopenable",fnsty,e);
X       else
X        {
X         if (flagxchkopen)
X           if (fcntl(fdsty,F_SETFL,0) == -1)
X         fatalerrp(6,"pty: fatal: can't fcntl pty",e);
X         return 0;
X        }
X      }
X    }
X
X       if (fdmty != -1) (void) close(fdmty);
X       if (fdsty != -1) (void) close(fdsty);
X       if (!(*(++c2)))
X     c2 = pty2;
X       fnmty[sizeof(DEVMTY) - 2] = fnsty[sizeof(DEVSTY) - 2] = *c2;
X      }
X     while (c2 != c2start);
X    }
X   if (!(*(++c1)))
X     c1 = pty1;
X  }
X while (c1 != c1start);
X return -1;
X}
X
Xchar fnmty[sizeof(DEVMTY)] = DEVMTY;
Xchar fnsty[sizeof(DEVSTY)] = DEVSTY;
Xchar pty1[sizeof(PTY1)] = PTY1;
Xchar pty2[sizeof(PTY2)] = PTY2;
X
Xmain(argc,argv)
Xint argc;
Xchar *argv[];
X{
X int opt;
X int f;
X
X uid = getuid();
X euid = geteuid();
X pid = getpid();
X pgrp = getpgrp(0);
X date = now();
X setusername();
X
X while ((opt = getopt(argc,argv,"qQvdDe3Ef:FjJsStTp:x:0ACHUVW")) != EOF)
X   switch(opt)
X    {
X     case 'A': fatalinfo(1,ptyauthor);
X     case 'C': fatalinfo(1,ptycopyright);
X     case 'H': fatalinfo(1,ptyhelp);
X     case 'U': fatalinfo(1,ptyusage);
X     case 'V': fatalinfo(1,ptyversion);
X     case 'W': fatalinfo(1,ptywarranty);
X     case '?': fatalinfo(1,ptyusage);
X     case 'q': flagquiet = 1; break;
X     case 'Q': flagquiet = 0; flagverbose = 0; break;
X     case 'v': flagverbose = 1; break;
X     case 'd': flagdetached = 1; flagjobctrl = 0; flagttymodes = 0; break;
X     case 'D': flagdetached = 0; flagjobctrl = 1; flagttymodes = 1; break;
X     case 'e': flagsameerr = 2; break;
X     case '3': flagsameerr = 1; break;
X     case 'E': flagsameerr = 0; break;
X     case 'f': flagfdpass = 1;
X           if (sscanf(optarg,"%d",&fdpass) < 1) fatalinfo(1,ptyusage);
X           break;
X     case 'F': flagfdpass = 0; break;
X     case 'j': flagjobctrl = 1; break;
X     case 'J': flagjobctrl = 0; break;
X     case 's': flagsession = 1; flagxutmp = 1; break;
X     case 'S': flagsession = 0; flagxutmp = 0; break;
X     case 't': flagttymodes = 1; break;
X     case 'T': flagttymodes = 0; break;
X     case '0': flagsameerr = 2; flagsession = 0; flagttymodes = 0;
X           flagxutmp = 0; /* XXX: also flagxwtmp = 0? */
X           flagpcbreak = 3; flagpraw = 3; flagpecho = 2; flagpnew = 2;
X           break;
X     case 'p': while (opt = *(optarg++))
X         switch(opt)
X          {
X           case 'c': flagpcbreak = 3; break;
X           case 'C': flagpcbreak = 2; break;
X           case 'd': flagpnew = 3; break;
X           case 'D': flagpnew = 2; break;
X           case 'e': flagpecho = 3; break;
X           case 'E': flagpecho = 2; break;
X           case 'n': flagpcrmod = 3; break;
X           case 'N': flagpcrmod = 2; break;
X           case 'r': flagpraw = 3; break;
X           case 'R': flagpraw = 2; break;
X           case 's': flagpcrt = 3; break;
X           case 'S': flagpcrt = 2; break;
X           case '0': flagpcbreak = 3; flagpraw = 3;
X                 flagpecho = 2; flagpnew = 2;
X                 break;
X           default: fatalinfo(1,ptyusage); break;
X          }
X               break;
X     case 'x': while (opt = *(optarg++))
X         switch(opt)
X          {
X           case 'c': flagxchown = 1; break;
X           case 'C': flagxchown = 0; break;
X           case 'u': flagxutmp = 1; break;
X           case 'U': flagxutmp = 0; break;
X           case 'w': flagxwtmp = 1; break;
X           case 'W': flagxwtmp = 0; break;
X           case 'x': flagxexcl = 1; break;
X           case 'X': flagxexcl = 0; break;
X           case 'e': flagxerrwo = 1; break;
X           case 'E': flagxerrwo = 0; break;
X           case 'n': flagxchkopen = 1; break;
X           case 'N': flagxchkopen = 0; break;
X           case 'o': flagxskipopen = 1; break;
X           case 'O': flagxskipopen = 0; break;
X           case 'r': flagxrandom = 1; break;
X           case 'R': flagxrandom = 0; break;
X           case 's': flagxsetuid = 1; break;
X           case 'S': flagxsetuid = 0; break;
X           default: fatalinfo(1,ptyusage); break;
X          }
X               break;
X    }
X argv += optind, argc -= optind;
X
X if (!*argv)
X   fatalinfo(1,ptyusage);
X
X /* Option forcing. */
X#ifdef NO_UTMP
X  if (flagxutmp) if (flagverbose) warnerr2("%s","pty: utmp forced off\n");
X  flagxutmp = 0;
X#endif
X#ifdef NO_WTMP
X  if (flagxwtmp) if (flagverbose) warnerr2("%s","pty: wtmp forced off\n");
X  flagxwtmp = 0;
X#endif
X#ifdef NO_CHOWN
X  if (flagxchown) if (flagverbose) warnerr2("%s","pty: chown forced off\n");
X  flagxchown = 0;
X#endif
X#ifdef NO_SESSION
X  if (flagsession) if (flagverbose) warnerr2("%s","pty: session forced off\n");
X  flagsession = 0;
X#endif
X#ifdef MUST_UTMP
X  if (flagxutmp) if (flagverbose) warnerr2("%s","pty: utmp forced on\n");
X  flagxutmp = 1;
X#endif
X#ifdef MUST_WTMP
X  if (flagxwtmp) if (flagverbose) warnerr2("%s","pty: wtmp forced on\n");
X  flagxwtmp = 1;
X#endif
X#ifdef MUST_CHOWN
X  if (flagxchown) if (flagverbose) warnerr2("%s","pty: chown forced on\n");
X  flagxchown = 1;
X#endif
X#ifdef MUST_SESSION
X  if (flagsession) if (flagverbose) warnerr2("%s","pty: session forced on\n");
X  flagsession = 1;
X#endif
X#ifdef NO_FDPASSING
X  if (flagfdpass) if (flagverbose) warnerr2("%s","pty: fd passing forced off\n");
X  flagfdpass = 0;
X#endif
X
X /* Option munging. */
X if (flagsession) flagsameerr = 0;
X if (flagdetached) flagttymodes = 0;
X if (flagxskipopen) flagxchkopen = 1;
X
X if (!flagxsetuid)
X  {
X   (void) setreuid(uid,uid);
X   euid = uid;
X  }
X
X
X sig_init();
X sig_sethandler(SIGALRM,nothing); sig_handle(SIGALRM);
X sig_default(SIGTTIN);
X sig_default(SIGTTOU);
X
X if (fdpass == -1) /* wow, was this a source of bugs. */
X  {
X   fdin = 0;
X   fdout = 1;
X  }
X
X if (flagdetached)
X  {
X   tty_initmodes(&tmopty,flagpcbreak,flagpnew,flagpecho,
X             flagpcrmod,flagpraw,flagpcrt);
X  }
X else
X  {
X   if ((fdtty = tty_getctrl()) == -1)
X     fatalerr(2,"pty: fatal: cannot find control terminal; try -d?\n");
X   if (tty_getmodes(fdtty,&tmotty) == -1)
X     fatalerr(3,"pty: fatal: cannot get current tty modes\n");
X     /* XXX: is there a way to recover more gracefully? */
X   tty_copymodes(&tmopty,&tmotty);
X   tty_mungemodes(&tmopty,flagpcbreak,flagpnew,flagpecho,
X              flagpcrmod,flagpraw,flagpcrt);
X   tty_copymodes(&tmochartty,&tmotty);
X   if (flagttymodes)
X     tty_charmode(&tmochartty);
X  }
X
X /* XXX: Here would be a good spot to include pty limits, say through */
X /* the file PTYDIR/LIMITS. Lines of the form user group num, saying */
X /* that user in that group is limited to num ptys, with * for all. */
X /* All pty use would have to be logged somewhere. Anyway, with a */
X /* streams-based pty, there wouldn't be much point to limits. */
X
X if (getfreepty(fnmty,fnsty,pty1,pty2) == -1)
X   fatalerr(5,"pty: fatal: no ptys available\n");
X
X if (flagverbose)
X   warnerr2("pty: successfully opened pty %s\n",fnsty);
X
X if (tty_modifymodes(fdtty,&tmochartty,&tmotty) == -1)
X  {
X   (void) tty_setmodes(fdtty,&tmotty); /* XXX --- gasp */
X   fatalerr(4,"pty: fatal: cannot set modes of original tty\n");
X  }
X
X/* In general, BSD systems check MAXUPRC against the effective uid, */
X/* rather than the real uid; and they check it during a fork(). */
X/* The combination of these annoying behaviors means that we have */
X/* to switch uids while forking, hence possibly losing any security */
X/* measures we may have set up before the fork(). Grrrr. */
X
X (void) setreuid(euid,uid);
X if ((f = fork()) == -1)
X  {
X   (void) tty_modifymodes(fdtty,&tmotty,&tmochartty);
X   fatalerr(7,"pty: fatal: cannot fork once\n");
X   /* After this, the signaller will handle tty modes. */
X  }
X else if (f == 0)
X   if ((f = fork()) == -1)
X    {
X     (void) kill(pid,SIGTERM); /*XXX*/
X     fatalerr(7,"pty: fatal: cannot fork twice\n");
X    }
X   else if (f == 0)
X    {
X     (void) setreuid(uid,euid);
X     slave(fnsty,argv);
X    }
X   else
X    {
X     (void) setreuid(uid,euid);
X     if (flagsession)
X       if (sessdir() == -1)
X         fatal(1);
X     master(fnsty,f);
X    }
X else
X  {
X   (void) setreuid(uid,euid);
X   if (flagsession)
X     if (sessdir() == -1)
X      {
X       fatalerr(8,"pty: fatal: cannot change to session directory\n");
X       (void) tty_modifymodes(fdtty,&tmotty,&tmochartty);
X      }
X   sigler(fnsty,f);
X  }
X
X fatal(9); /* just in case */
X /*NOTREACHED*/
X}
END_OF_FILE
  if test 10563 -ne `wc -c <'pty.c'`; then
    echo shar: \"'pty.c'\" unpacked with wrong size!
  fi
  # end of 'pty.c'
fi
echo shar: End of archive 2 \(of 6\).
cp /dev/null ark2isdone
MISSING=""
for I in 1 2 3 4 5 6 ; do
    if test ! -f ark${I}isdone ; then
    MISSING="${MISSING} ${I}"
    fi
done
if test "${MISSING}" = "" ; then
    echo You have unpacked all 6 archives.
    rm -f ark[1-9]isdone
else
    echo You still must unpack the following archives:
    echo "        " ${MISSING}
fi
exit 0
exit 0 # Just in case...