Path: utzoo!attcan!uunet!ginosko!xanth!indri!nic.MR.NET!thor.acc.stolaf.edu!mackenzi
From: mackenzi@thor.acc.stolaf.edu (David MacKenzie)
Newsgroups: alt.sources
Subject: comsat for System V with FIFO
Keywords: comsat mail biff System V
Message-ID: <4487@thor.acc.stolaf.edu>
Date: 15 Aug 89 01:27:00 GMT
Distribution: na
Organization: Environmental Defense Fund
Lines: 595


As a long-time BSD user I got attached to the biff and comsat programs;
when I started using a System V machine it became harder to know when I had
new mail.  So I decided to convert the freed BSD comsat program (from
uunet) to System V.  We don't have sockets or other networking stuff on
our systems so I changed it to use a named pipe (FIFO) instead.

I didn't find the source code to biff on uunet so I wrote my own public
domain version.

I haven't yet adapted smail or any other mail delivery program to actually
send a message to comsat yet; right now I'm just experimenting with it, and
"echo dave@0 > /etc/comsat.fifo" is sufficient.

In case anyone else is interested, here are comsat and biff for System V.
Comments welcome.


#! /bin/sh
# This is a shell archive.  Remove anything before this line, then unpack
# it by saving it into a file and typing "sh file".  To overwrite existing
# files, type "sh file -c".  You can also feed this as standard input via
# unshar, or by typing "sh <file", e.g..  If this archive is complete, you
# will see the following message at the end:
#		"End of shell archive."
# Contents:  comsat.c biff.c
# Wrapped by mackenzi@thor on Mon Aug 14 20:13:03 1989
PATH=/bin:/usr/bin:/usr/ucb ; export PATH
if test -f 'comsat.c' -a "${1}" != "-c" ; then 
  echo shar: Will not clobber existing file \"'comsat.c'\"
else
echo shar: Extracting \"'comsat.c'\" \(10120 characters\)
sed "s/^X//" >'comsat.c' <<'END_OF_FILE'
X/*
X * Copyright (c) 1980 Regents of the University of California.
X * All rights reserved.
X *
X * Redistribution and use in source and binary forms are permitted
X * provided that the above copyright notice and this paragraph are
X * duplicated in all such forms and that any documentation,
X * advertising materials, and other materials related to such
X * distribution and use acknowledge that the software was developed
X * by the University of California, Berkeley.  The name of the
X * University may not be used to endorse or promote products derived
X * from this software without specific prior written permission.
X * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
X * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
X * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
X */
X
X#ifndef lint
Xchar copyright[] =
X"@(#) Copyright (c) 1980 Regents of the University of California.\n\
X All rights reserved.\n";
X#endif /* not lint */
X
X/* comsat - daemon to notify registered users of new mail
X   Usage: comsat > /dev/null 2> errorlog &
X
X   Receives one line messages of the form
X   user@mailbox-offset\n
X   on a named pipe, and if the user is logged on and "biff y" (owner
X   execute bit of tty is turned on), prints a message summarizing the new
X   mail on the user's screen.
X
X   Converted for System V with FIFO by David MacKenzie
X   Latest revision: 08/14/89 */
X
X#include <stdio.h>
X#include <sys/types.h>
X#include <sys/stat.h>
X#include <utmp.h>
X#include <signal.h>
X#include <errno.h>
X#include <fcntl.h>
X#include <termio.h>
X#include <string.h>
X#include <varargs.h>
X#include <sys/utsname.h>
X
X/* BSD-compatible constants for lseek. */
X#define L_SET 0
X#define L_INCR 1
X#define L_XTND 2
X
X/* The directory where system mailboxes are located. */
X#define SYSMAILDIR "/usr/mail"
X
X/* Path of the named pipe used to send messages to this program. */
X#define FIFO "/etc/comsat.fifo"
X
X/* The number of seconds between checks of the utmp. */
X#define ALARM_INTERVAL 15
X
Xchar *malloc ();
Xchar *realloc ();
Xoff_t atol ();
Xoff_t fseek ();
Xoff_t lseek ();
Xtime_t time ();
X
Xchar *xmalloc ();
Xchar *xrealloc ();
Xint reap_children ();
Xint read_utmp ();
Xvoid mail_for ();
Xvoid msg_perror_fatal ();
Xvoid notify ();
Xvoid summarize_new_mail ();
X
X/* This machine's host name, used in the notification message. */
Xchar hostname[10];
X
X/* Contents of the utmp. */
Xstruct utmp *utmp;
X
X/* The last time an alarm was set. */
Xtime_t alarm_set;
X
X/* Number of entries in `utmp'. */
Xint nutmp;
X
X/* File descriptor for reading the utmp. */
Xint utfd;
X
X/* The name this program was run with, for error messages. */
Xchar *program_name;
X
X/* ARGSUSED */
Xint
Xmain (argc, argv)
X     int argc;
X     char **argv;
X{
X  int fifd;
X  FILE *fifp;
X  char msgbuf[100];
X
X  program_name = argv[0];
X
X  /* Open the fifo with O_NDELAY so open won't block waiting for another
X     process to open the fifo for writing. */
X  fifd = open (FIFO, O_RDONLY | O_NDELAY);
X  if (fifd == -1)
X    msg_perror_fatal ("Cannot open %s for reading", FIFO);
X  /* Turn off O_NDELAY on the fifo for more efficient cpu usage. */
X  if (fcntl (fifd, F_SETFL, 0) == -1)
X    msg_perror_fatal ("Cannot fcntl %s", FIFO);
X  fifp = fdopen (fifd, "r");
X  if (fifp == NULL)
X    msg_perror_fatal ("Cannot fdopen %s", FIFO);
X
X  utfd = open (UTMP_FILE, O_RDONLY);
X  if (utfd == -1)
X    msg_perror_fatal ("Cannot read %s", UTMP_FILE);
X
X  if (chdir (SYSMAILDIR) == -1)
X    msg_perror_fatal ("Cannot chdir to %s", SYSMAILDIR);
X
X  utmp = NULL;
X  nutmp = 0;
X  gethostname (hostname, sizeof (hostname));
X  signal (SIGCLD, reap_children);
X
X  read_utmp ();
X  signal (SIGALRM, read_utmp);
X
X  while (1)
X    {
X      while (fgets (msgbuf, sizeof msgbuf, fifp) == NULL)
X        sleep (1);
X      if (nutmp == 0)
X	continue;		/* No one has logged in yet. */
X      /* Don't let automatic utmp updating corrupt the in-core copy while
X         we're using it. */
X      signal (SIGALRM, SIG_IGN);
X      mail_for (msgbuf);
X      /* If we missed a utmp update while ignoring the signal, do it
X         manually. */
X      if (time ((time_t *) 0) - alarm_set >= ALARM_INTERVAL)
X	read_utmp ();
X      else
X	signal (SIGALRM, read_utmp);
X    }
X  /* NOTREACHED */
X}
X
X/* SIGCLD handler.  Called when a child process dies.
X   Is this necessary under System V? */
X
Xint
Xreap_children ()
X{
X  wait ((int *) 0);
X}
X
X/* SIGALRM handler.  Every ALARM_INTERVAL seconds, read a current copy
X   of the utmp into `utmp'. */
X
Xint
Xread_utmp ()
X{
X  static unsigned utmp_size = 0;	/* Bytes allocated for `utmp'. */
X  static unsigned utmp_mtime = 0;	/* Last modification time of utmp. */
X  struct stat stats;
X
X  if (fstat (utfd, &stats) == -1)
X    msg_perror_fatal ("Cannot fstat utmp");
X  if (stats.st_mtime > utmp_mtime)
X    {
X      utmp_mtime = stats.st_mtime;
X      if (stats.st_size > utmp_size)
X	{
X	  utmp_size = stats.st_size + 10 * sizeof (struct utmp);
X	  utmp = (struct utmp *) xrealloc ((char *) utmp, utmp_size);
X	}
X      if (lseek (utfd, 0L, L_SET) < 0)
X	msg_perror_fatal ("Cannot seek to beginning of utmp");
X      nutmp = read (utfd, utmp, (int) stats.st_size);
X      if (nutmp == -1)
X	msg_perror_fatal ("Cannot read utmp");
X      nutmp /= sizeof (struct utmp);
X    }
X  time (&alarm_set);
X  alarm ((unsigned) ALARM_INTERVAL);
X  signal (SIGALRM, read_utmp);
X}
X
X/* `name' has the form "user@mailbox-offset\n".  Check whether "user" is
X   logged on; if so, try to notify them of the new mail. */
X
Xvoid
Xmail_for (name)
X     char *name;
X{
X  struct utmp *utp;
X  char *cp;
X  off_t offset;
X
X  cp = strchr (name, '@');
X  if (cp == NULL)
X    {
X      fprintf (stderr, "%s: Invalid message: %s\n", program_name, name);
X      return;
X    }
X  *cp++ = '\0';
X  offset = atol (cp);
X  utp = &utmp[nutmp];
X  while (--utp >= utmp)
X    {
X      if (!strncmp (utp->ut_user, name, sizeof (utmp[0].ut_user)))
X	notify (utp, offset);
X    }
X}
X
X/* The carriage return character needed for the terminal being notified;
X   it will be the null string if the terminal driver or the terminal
X   is supplying a carriage return automatically with each newline. */
Xstatic char *cr;
X
X/* If the user described in `utp' is logged on and "biff y", notify them
X   of the new mail in their system mailbox at offset `offset'. */
X
Xvoid
Xnotify (utp, offset)
X     struct utmp *utp;
X     off_t offset;
X{
X  static char tty[20] = "/dev/";
X  struct termio termio;
X  FILE *tp;
X  char name[sizeof (utmp[0].ut_user) + 1];
X  struct stat stats;
X
X  strncpy (tty + 5, utp->ut_line, sizeof (utp->ut_line));
X  if (stat (tty, &stats) || !(stats.st_mode & S_IEXEC))
X    return;
X  switch (fork ())
X    {
X    case -1:
X      msg_perror_fatal ("Cannot fork");
X    case 0:
X      break;
X    default:
X      return;
X    }
X  signal (SIGALRM, SIG_DFL);
X  alarm ((unsigned) 30);
X  tp = fopen (tty, "w");
X  if (tp == NULL)
X    _exit (1);
X  ioctl (fileno (tp), TCGETA, &termio);
X  cr = (termio.c_oflag & OPOST) && (termio.c_oflag & ONLCR)
X    || (termio.c_oflag & ONLRET) ? "" : "\r";
X  strncpy (name, utp->ut_user, sizeof (utp->ut_user));
X  name[sizeof (name) - 1] = '\0';
X  fprintf (tp, "%s\n\007New mail for %s@%.*s\007 has arrived:%s\n----%s\n",
X	   cr, name, sizeof (hostname), hostname, cr, cr);
X  summarize_new_mail (tp, name, offset);
X  fclose (tp);
X  _exit (0);
X}
X
X/* Print the first 7 lines or 560 characters (whichever comes first) of
X   the new mail message that starts at byte `offset' in file `name' to
X   stream `tp'.  Skip header lines other than From, Subject, [To, and Date].
X   `name' is just the user's name, since the system mailboxes are in the
X   current directory. */
X
Xvoid
Xsummarize_new_mail (tp, name, offset)
X     FILE *tp;
X     char *name;
X     off_t offset;
X{
X  char *cp;
X  FILE *fi;
X  int linecnt;
X  int charcnt;
X  int inheader;
X  char line[BUFSIZ];
X
X  fi = fopen (name, "r");
X  if (fi == NULL)
X    return;
X  if (fseek (fi, offset, L_SET))
X    return;
X  linecnt = 7;
X  charcnt = 560;
X  inheader = 1;
X  while (fgets (line, sizeof (line), fi) != NULL)
X    {
X      if (inheader)
X	{
X	  if (line[0] == '\n')
X	    {
X	      fprintf (tp, "%s\n", cr);
X	      inheader = 0;
X	      continue;
X	    }
X	  /* Skip header continuation lines and non-essential header lines. */
X	  if (line[0] == ' ' || line[0] == '\t' ||
X	      strncmp (line, "From:", 5) &&
X	      strncmp (line, "Subject:", 8))
X	    continue;
X	}
X      if (linecnt <= 0 || charcnt <= 0)
X	{
X	  fprintf (tp, "...more...%s\n", cr);
X	  return;
X	}
X      cp = strchr (line, '\n');
X      if (cp)
X	*cp = '\0';
X      fprintf (tp, "%s%s\n", line, cr);
X      charcnt -= strlen (line);
X      linecnt--;
X    }
X  fprintf (tp, "----%s\n", cr);
X}
X
X/* Simulate the BSD gethostname(2) system call on System V.  */
X
Xint
Xgethostname (name, length)
X     char *name;
X     int length;
X{
X  struct utsname uts;
X
X  if (uname (&uts) < 0)
X    return -1;
X  strncpy (name, uts.nodename, length);
X  return 0;
X}
X
Xstatic void
Xmemory_out ()
X{
X  fprintf (stderr, "%s: Virtual memory exhausted\n", program_name);
X  exit (1);
X}
X
X/* Allocate `n' bytes of memory dynamically, with error checking.  */
X
Xchar *
Xxmalloc (n)
X     unsigned n;
X{
X  char *p;
X
X  p = malloc (n);
X  if (p == 0)
X    memory_out ();
X  return p;
X}
X
X/* Change the size of an allocated block of memory `p' to `n' bytes,
X   with error checking.
X   If `p' is NULL, run xmalloc.
X   If `n' is 0, run free and return NULL.  */
X
Xchar *
Xxrealloc (p, n)
X     char *p;
X     unsigned n;
X{
X  if (p == 0)
X    return xmalloc (n);
X  if (n == 0)
X    {
X      free (p);
X      return 0;
X    }
X  p = realloc (p, n);
X  if (p == 0)
X    memory_out ();
X  return p;
X}
X
X/* ANSI C function. */
X
Xchar *
Xstrerror (n)
X     int n;
X{
X  extern char *sys_errlist[];
X  extern int sys_nerr;
X
X  return n >= 0 && n < sys_nerr ? sys_errlist[n] : "Unknown error";
X}
X
X/* Print "program_name: str_and_optional_args: perror_message" on stderr,
X   then exit with error status. */
X/* VARARGS */
Xvoid
Xmsg_perror_fatal (str, va_alist)
X     char *str;
X     va_dcl
X{
X  va_list args;
X  extern int errno;
X  int save_errno;
X
X  save_errno = errno;
X  fprintf (stderr, "%s: ", program_name);
X  va_start (args);
X  vfprintf (stderr, str, args);
X  va_end (args);
X  fprintf (stderr, ": %s\n", strerror (save_errno));
X  exit (1);
X}
END_OF_FILE
if test 10120 -ne `wc -c <'comsat.c'`; then
    echo shar: \"'comsat.c'\" unpacked with wrong size!
fi
# end of 'comsat.c'
fi
if test -f 'biff.c' -a "${1}" != "-c" ; then 
  echo shar: Will not clobber existing file \"'biff.c'\"
else
echo shar: Extracting \"'biff.c'\" \(2106 characters\)
sed "s/^X//" >'biff.c' <<'END_OF_FILE'
X/* biff - accept or refuse new mail messages from comsat
X
X   Usage: biff [yn]
X
X   David MacKenzie
X   public domain
X   Latest revision: 08/14/89 */
X
X#include <stdio.h>
X#include <sys/types.h>
X#include <sys/stat.h>
X#include <varargs.h>
X
Xchar *ttyname ();
X
Xchar *any_ttyname ();
Xvoid msg_perror_fatal ();
Xvoid usage ();
X
Xchar *program_name;
X
Xint
Xmain (argc, argv)
X     int argc;
X     char **argv;
X{
X  struct stat stats;
X  char *tty;
X
X  program_name = argv[0];
X  tty = any_ttyname ();
X  if (tty == NULL)
X    {
X      fprintf (stderr, "%s: Not connected to a terminal\n", argv[0]);
X      exit (1);
X    }
X  if (stat (tty, &stats) == -1)
X    msg_perror_fatal ("Cannot stat %s", tty);
X  switch (argc)
X    {
X    case 1:
X      printf ("is %c\n", (stats.st_mode & S_IEXEC) ? 'y' : 'n');
X      break;
X    case 2:
X      switch (*argv[1])
X	{
X	case 'y':
X	  if (chmod (tty, stats.st_mode | S_IEXEC) == -1)
X	    msg_perror_fatal ("Cannot change mode of %s", tty);
X	  break;
X	case 'n':
X	  if (chmod (tty, stats.st_mode & ~S_IEXEC) == -1)
X	    msg_perror_fatal ("Cannot change mode of %s", tty);
X	  break;
X	default:
X	  usage ();
X	}
X      break;
X    default:
X      usage ();
X    }
X  exit (0);
X  /* NOTREACHED */
X}
X
Xchar *
Xany_ttyname ()
X{
X  char *tty;
X
X  tty = ttyname (2);
X  if (tty)
X    return tty;
X  tty = ttyname (1);
X  if (tty)
X    return tty;
X  tty = ttyname (0);
X  if (tty)
X    return tty;
X  return NULL;
X}
X
X/* ANSI C function. */
X
Xchar *
Xstrerror (n)
X     int n;
X{
X  extern char *sys_errlist[];
X  extern int sys_nerr;
X
X  return n >= 0 && n < sys_nerr ? sys_errlist[n] : "Unknown error";
X}
X
X/* Print "program_name: str_and_optional_args: perror_message" on stderr,
X   then exit with error status. */
X/* VARARGS */
Xvoid
Xmsg_perror_fatal (str, va_alist)
X     char *str;
X     va_dcl
X{
X  va_list args;
X  extern int errno;
X  int save_errno;
X
X  save_errno = errno;
X  fprintf (stderr, "%s: ", program_name);
X  va_start (args);
X  vfprintf (stderr, str, args);
X  va_end (args);
X  fprintf (stderr, ": %s\n", strerror (save_errno));
X  exit (1);
X}
X
Xvoid
Xusage ()
X{
X  fprintf (stderr, "Usage: %s [yn]\n", program_name);
X  exit (1);
X}
END_OF_FILE
if test 2106 -ne `wc -c <'biff.c'`; then
    echo shar: \"'biff.c'\" unpacked with wrong size!
fi
# end of 'biff.c'
fi
echo shar: End of shell archive.
exit 0
-- 
David MacKenzie
mackenzi@thor.stolaf.edu or edf@rocky2.rockefeller.edu