/*
* Copyright 2005 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/*
* Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T
* All Rights Reserved.
*/
/*
* Copyright (c) 1980 Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted provided
* that: (1) source distributions retain this entire copyright notice and
* comment, and (2) distributions including binaries display the following
* acknowledgement: ``This product includes software developed by the
* University of California, Berkeley and its contributors'' in the
* documentation or other materials provided with the distribution and in
* all advertising materials mentioning features or use of this software.
* Neither the name of the University nor the names of its contributors may
* be used to endorse or promote products derived from this software without
* specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <sys/file.h>
#include <fcntl.h>
#include <ctype.h>
#include <string.h>
#include <netinet/in.h>
#include <stdio.h>
#include <sys/ttold.h>
#include <utmpx.h>
#include <signal.h>
#include <errno.h>
#include <sys/param.h> /* for MAXHOSTNAMELEN */
#include <netdb.h>
#include <syslog.h>
#include <sys/ioctl.h>
#include <pwd.h>
/*
* comsat
*/
#ifndef UTMPX_FILE
#define UTMPX_FILE "/etc/utmpx"
#endif /* UTMPX_FILE */
int debug = 0;
#define dsyslog if (debug) syslog
struct sockaddr_in sin = { AF_INET };
char hostname[MAXHOSTNAMELEN];
struct utmpx *utmp = NULL;
int nutmp;
int uf;
unsigned utmpmtime = 0; /* last modification time for utmp */
unsigned utmpsize = 0; /* last malloced size for utmp */
time_t lastmsgtime;
#ifndef SYSV
int reapchildren();
#else
#define rindex strrchr
#define index strchr
#define signal(s, f) sigset((s), (f))
#ifndef sigmask
#define sigmask(m) (1 << ((m)-1))
#endif
#define set2mask(setp) ((setp)->__sigbits[0])
#define mask2set(mask, setp) \
((mask) == -1 ? sigfillset(setp) : (((setp)->__sigbits[0]) = (mask)))
static int
sigsetmask(mask)
int mask;
{
sigset_t oset;
sigset_t nset;
(void) sigprocmask(0, (sigset_t *)0, &nset);
mask2set(mask, &nset);
(void) sigprocmask(SIG_SETMASK, &nset, &oset);
return (set2mask(&oset));
}
static int
sigblock(mask)
int mask;
{
sigset_t oset;
sigset_t nset;
(void) sigprocmask(0, (sigset_t *)0, &nset);
mask2set(mask, &nset);
(void) sigprocmask(SIG_BLOCK, &nset, &oset);
return (set2mask(&oset));
}
#endif /* SYSV */
#define MAXIDLE 120
#define NAMLEN (sizeof (uts[0].ut_name) + 1)
void jkfprintf(FILE *tp, char *name, int mbox, int offset);
void mailfor(char *name);
void notify(struct utmpx *utp, int offset);
void onalrm(int sig);
int
main(argc, argv)
int argc;
char *argv[];
{
register int cc;
char buf[BUFSIZ];
char msgbuf[100];
struct sockaddr_in from;
socklen_t fromlen;
int c;
extern int optind;
extern int getopt();
extern char *optarg;
openlog("comsat", 0, LOG_DAEMON);
while ((c = getopt(argc, argv, "d")) != -1) {
switch ((char)c) {
case'd':
debug++;
break;
default:
syslog(LOG_ERR, "invalid argument %s", argv[optind]);
exit(1);
}
}
/* verify proper invocation */
fromlen = (socklen_t)sizeof (from);
if (getsockname(0, (struct sockaddr *)&from, &fromlen) < 0) {
fprintf(stderr, "%s: ", argv[0]);
perror("getsockname");
_exit(1);
}
#ifdef SYSV
chdir("/var/mail");
#else
chdir("/var/spool/mail");
#endif /* SYSV */
if ((uf = open(UTMPX_FILE, 0)) < 0) {
syslog(LOG_ERR, "%s: %m", UTMPX_FILE);
(void) recv(0, msgbuf, sizeof (msgbuf) - 1, 0);
exit(1);
}
(void) time(&lastmsgtime);
(void) gethostname(hostname, sizeof (hostname));
onalrm(0);
(void) signal(SIGALRM, onalrm);
(void) signal(SIGTTOU, SIG_IGN);
#ifndef SYSV
(void) signal(SIGCHLD, reapchildren);
#else
(void) signal(SIGCHLD, SIG_IGN); /* no zombies */
#endif /* SYSV */
for (;;) {
cc = recv(0, msgbuf, sizeof (msgbuf) - 1, 0);
if (cc <= 0) {
if (errno != EINTR)
sleep(1);
errno = 0;
continue;
}
if (nutmp == 0) /* no users (yet) */
continue;
sigblock(sigmask(SIGALRM));
msgbuf[cc] = 0;
(void) time(&lastmsgtime);
mailfor(msgbuf);
sigsetmask(0);
}
}
#ifndef SYSV
reapchildren()
{
while (wait3((struct wait *)0, WNOHANG, (struct rusage *)0) > 0)
;
}
#endif /* SYSV */
/* ARGSUSED */
void
onalrm(int sig)
{
struct stat statbf;
time_t now;
(void) time(&now);
if ((ulong_t)now - (ulong_t)lastmsgtime >= MAXIDLE)
exit(0);
dsyslog(LOG_DEBUG, "alarm\n");
alarm(15);
fstat(uf, &statbf);
if (statbf.st_mtime > utmpmtime) {
dsyslog(LOG_DEBUG, " changed\n");
utmpmtime = statbf.st_mtime;
if (statbf.st_size > utmpsize) {
utmpsize = statbf.st_size + 10 * sizeof (struct utmpx);
if (utmp)
utmp = (struct utmpx *)realloc(utmp, utmpsize);
else
utmp = (struct utmpx *)malloc(utmpsize);
if (! utmp) {
dsyslog(LOG_DEBUG, "malloc failed\n");
exit(1);
}
}
lseek(uf, 0, 0);
nutmp = read(uf, utmp, statbf.st_size)/sizeof (struct utmpx);
} else
dsyslog(LOG_DEBUG, " ok\n");
}
void
mailfor(name)
char *name;
{
struct utmpx *utp = &utmp[nutmp];
register char *cp;
char *rindex();
int offset;
/*
* Don't bother doing anything if nobody is
* logged into the system.
*/
if (utmp == NULL || nutmp == 0)
return;
dsyslog(LOG_DEBUG, "mailfor %s\n", name);
cp = name;
while (*cp && *cp != '@')
cp++;
if (*cp == 0) {
dsyslog(LOG_DEBUG, "bad format\n");
return;
}
*cp = 0;
offset = atoi(cp+1);
while (--utp >= utmp)
if ((utp->ut_type == USER_PROCESS) &&
(!strncmp(utp->ut_name, name, sizeof (utmp[0].ut_name))))
notify(utp, offset);
}
char *cr;
void
notify(utp, offset)
struct utmpx *utp;
{
FILE *tp;
struct sgttyb gttybuf;
char tty[sizeof (utmp[0].ut_line) + 5];
char name[sizeof (utmp[0].ut_name) + 1];
struct stat stb, stl;
time_t timep[2];
struct passwd *pwd;
int fd, mbox;
strcpy(tty, "/dev/");
strncat(tty, utp->ut_line, sizeof (utp->ut_line));
dsyslog(LOG_DEBUG, "notify %s on %s\n", utp->ut_name, tty);
if (stat(tty, &stb) == -1) {
dsyslog(LOG_DEBUG, "can't stat tty\n");
return;
}
if ((stb.st_mode & 0100) == 0) {
dsyslog(LOG_DEBUG, "wrong mode\n");
return;
}
if (fork())
return;
signal(SIGALRM, SIG_DFL);
alarm(30);
strncpy(name, utp->ut_name, sizeof (utp->ut_name));
name[sizeof (name) - 1] = '\0';
/*
* Do all operations that check protections as the user who
* will be getting the biff.
*/
if ((pwd = getpwnam(name)) == (struct passwd *)-1) {
dsyslog(LOG_DEBUG, "getpwnam failed\n");
exit(1);
}
if (setuid(pwd->pw_uid) == -1) {
dsyslog(LOG_DEBUG, "setuid failed\n");
exit(1);
}
/*
* We need to make sure that the tty listed in the utmp
* file really is a tty device so that a corrupted utmp
* file doesn't cause us to over-write a real file.
*/
if ((fd = open(tty, O_RDWR)) == -1) {
dsyslog(LOG_DEBUG, "can't open tty");
exit(1);
}
if (isatty(fd) == 0) {
dsyslog(LOG_DEBUG, "line listed in utmp file is not a tty\n");
exit(1);
}
/*
* For the case where the user getting the biff is root,
* we need to make sure that the tty we will be sending
* the biff to is also owned by root.
*
* Check after open, to prevent race on open.
*/
if (fstat(fd, &stb) != 0 || stb.st_uid != pwd->pw_uid) {
dsyslog(LOG_DEBUG,
"tty is not owned by user getting the biff\n");
exit(1);
}
/*
* Prevent race by doing fdopen on fd, not fopen
* Fopen opens w/ O_CREAT, which is dangerous too
*/
if ((tp = fdopen(fd, "w")) == 0) {
dsyslog(LOG_DEBUG, "fdopen failed\n");
exit(-1);
}
if (ioctl(fd, TIOCGETP, &gttybuf) == -1) {
dsyslog(LOG_DEBUG, "ioctl TIOCGETP failed\n");
exit(1);
}
cr = (gttybuf.sg_flags&CRMOD) && !(gttybuf.sg_flags&RAW) ? "" : "\r";
fprintf(tp, "%s\n\007New mail for %s@%.*s\007 has arrived:%s\n",
cr, name, sizeof (hostname), hostname, cr);
fprintf(tp, "----%s\n", cr);
if ((mbox = open(name, O_RDONLY)) == -1) {
dsyslog(LOG_DEBUG, "can't open mailbox for %s", name);
exit(1);
}
/*
* In case of a worldwritable mail spool directory, we must take
* care we don't open and read from the wrong file.
*/
if (fstat(mbox, &stb) == -1 || lstat(name, &stl) == -1) {
dsyslog(LOG_DEBUG, "stat() failed on mail file\n");
exit(1);
}
/*
* Here we make sure that the file wasn't a hardlink or softlink
* while we opened it and that it wasn't changed afterwards
*/
if (!S_ISREG(stl.st_mode) ||
stl.st_dev != stb.st_dev ||
stl.st_ino != stb.st_ino ||
stl.st_uid != pwd->pw_uid ||
stb.st_nlink != 1) {
dsyslog(LOG_DEBUG, "mail spool file must be plain file\n");
exit(1);
}
timep[0] = stb.st_atime;
timep[1] = stb.st_mtime;
jkfprintf(tp, name, mbox, offset);
utime(name, timep);
exit(0);
}
void
jkfprintf(tp, name, mbox, offset)
register FILE *tp;
char *name;
int mbox;
{
register FILE *fi;
register int linecnt, charcnt;
char line[BUFSIZ];
int inheader;
dsyslog(LOG_DEBUG, "HERE %s's mail starting at %d\n",
name, offset);
if ((fi = fdopen(mbox, "r")) == NULL) {
dsyslog(LOG_DEBUG, "Cant read the mail\n");
return;
}
fseek(fi, offset, L_SET);
/*
* Print the first 7 lines or 560 characters of the new mail
* (whichever comes first). Skip header crap other than
* From, Subject, To, and Date.
*/
linecnt = 7;
charcnt = 560;
inheader = 1;
while (fgets(line, sizeof (line), fi) != NULL) {
register char *cp;
char *index();
int cnt;
int i;
if (linecnt <= 0 || charcnt <= 0) {
fprintf(tp, "...more...%s\n", cr);
return;
}
if (strncmp(line, "From ", 5) == 0)
continue;
if (inheader && (line[0] == ' ' || line[0] == '\t'))
continue;
cp = index(line, ':');
if (cp == 0 || (index(line, ' ') && index(line, ' ') < cp))
inheader = 0;
else
cnt = cp - line;
if (inheader &&
strncmp(line, "Date", cnt) &&
strncmp(line, "From", cnt) &&
strncmp(line, "Subject", cnt) &&
strncmp(line, "To", cnt))
continue;
cp = index(line, '\n');
if (cp)
*cp = '\0';
for (i = strlen(line); i-- > 0; )
if (!isprint(line[i]))
line[i] = ' ';
fprintf(tp, "%s%s\n", line, cr);
linecnt--, charcnt -= strlen(line);
}
fprintf(tp, "----%s\n", cr);
}