usr/src/libexec/comsat/comsat.c

/*
 * Copyright (c) 1980 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the University of California, Berkeley.  The name of the
 * University may not 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 MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#ifndef lint
char copyright[] =
"@(#) Copyright (c) 1980 Regents of the University of California.\n\
 All rights reserved.\n";
#endif /* not lint */

#ifndef lint
static char sccsid[] = "@(#)comsat.c    5.15 (Berkeley) %G%";
#endif /* not lint */

#include <sys/param.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/file.h>
#include <sys/wait.h>

#include <netinet/in.h>

#include <stdio.h>
#include <sgtty.h>
#include <utmp.h>
#include <signal.h>
#include <errno.h>
#include <netdb.h>
#include <syslog.h>
#include <strings.h>

#include "pathnames.h"

/*
 * comsat
 */
int     debug = 0;
#define dsyslog if (debug) syslog

#define MAXIDLE 120

char    hostname[MAXHOSTNAMELEN];
struct  utmp *utmp = NULL;
time_t  lastmsgtime, time();
int     nutmp, uf;

main(argc, argv)
        int argc;
        char **argv;
{
        extern int errno;
        register int cc;
        char msgbuf[100];
        struct sockaddr_in from;
        int fromlen, reapchildren(), onalrm();

        /* verify proper invocation */
        fromlen = sizeof (from);
        if (getsockname(0, &from, &fromlen) < 0) {
                fprintf(stderr, "%s: ", argv[0]);
                perror("getsockname");
                exit(1);
        }
        openlog("comsat", LOG_PID, LOG_DAEMON);
        if (chdir(_PATH_MAIL)) {
                syslog(LOG_ERR, "chdir: %s: %m", _PATH_MAIL);
                exit(1);
        }
        if ((uf = open(_PATH_UTMP, O_RDONLY, 0)) < 0) {
                syslog(LOG_ERR, ".main: %s: %m", _PATH_UTMP);
                (void) recv(0, msgbuf, sizeof (msgbuf) - 1, 0);
                exit(1);
        }
        (void)time(&lastmsgtime);
        (void)gethostname(hostname, sizeof (hostname));
        onalrm();
        (void)signal(SIGALRM, onalrm);
        (void)signal(SIGTTOU, SIG_IGN);
        (void)signal(SIGCHLD, reapchildren);
        for (;;) {
                cc = recv(0, msgbuf, sizeof (msgbuf) - 1, 0);
                if (cc <= 0) {
                        if (errno != EINTR)
                                sleep(1);
                        errno = 0;
                        continue;
                }
                if (!nutmp)             /* no one has logged in yet */
                        continue;
                sigblock(sigmask(SIGALRM));
                msgbuf[cc] = 0;
                (void)time(&lastmsgtime);
                mailfor(msgbuf);
                sigsetmask(0L);
        }
}

reapchildren()
{
        while (wait3((union wait *)NULL, WNOHANG, (struct rusage *)NULL) > 0);
}

onalrm()
{
        static u_int utmpsize;          /* last malloced size for utmp */
        static u_int utmpmtime;         /* last modification time for utmp */
        struct stat statbf;
        off_t lseek();
        char *malloc(), *realloc();

        if (time((time_t *)NULL) - lastmsgtime >= MAXIDLE)
                exit(0);
        (void)alarm((u_int)15);
        (void)fstat(uf, &statbf);
        if (statbf.st_mtime > utmpmtime) {
                utmpmtime = statbf.st_mtime;
                if (statbf.st_size > utmpsize) {
                        utmpsize = statbf.st_size + 10 * sizeof(struct utmp);
                        if (utmp)
                                utmp = (struct utmp *)realloc((char *)utmp, utmpsize);
                        else
                                utmp = (struct utmp *)malloc(utmpsize);
                        if (!utmp) {
                                syslog(LOG_ERR, "malloc failed");
                                exit(1);
                        }
                }
                (void)lseek(uf, 0L, L_SET);
                nutmp = read(uf, utmp, (int)statbf.st_size)/sizeof(struct utmp);
        }
}

mailfor(name)
        char *name;
{
        register struct utmp *utp = &utmp[nutmp];
        register char *cp;
        off_t offset, atol();

        if (!(cp = index(name, '@')))
                return;
        *cp = '\0';
        offset = atoi(cp + 1);
        while (--utp >= utmp)
                if (!strncmp(utp->ut_name, name, sizeof(utmp[0].ut_name)))
                        notify(utp, offset);
}

static char     *cr;

notify(utp, offset)
        register struct utmp *utp;
        off_t offset;
{
        static char tty[20] = _PATH_DEV;
        struct sgttyb gttybuf;
        FILE *tp;
        char name[sizeof (utmp[0].ut_name) + 1];
        struct stat stb;

        (void)strncpy(tty + 5, utp->ut_line, sizeof(utp->ut_line));
        if (stat(tty, &stb) || !(stb.st_mode & S_IEXEC)) {
                dsyslog(LOG_DEBUG, "%s: wrong mode on %s", utp->ut_name, tty);
                return;
        }
        dsyslog(LOG_DEBUG, "notify %s on %s\n", utp->ut_name, tty);
        if (fork())
                return;
        (void)signal(SIGALRM, SIG_DFL);
        (void)alarm((u_int)30);
        if ((tp = fopen(tty, "w")) == NULL) {
                dsyslog(LOG_ERR, "fopen of tty %s failed", tty);
                _exit(-1);
        }
        (void)ioctl(fileno(tp), TIOCGETP, &gttybuf);
        cr = (gttybuf.sg_flags&CRMOD) && !(gttybuf.sg_flags&RAW) ? "" : "\r";
        (void)strncpy(name, utp->ut_name, sizeof (utp->ut_name));
        name[sizeof (name) - 1] = '\0';
        fprintf(tp, "%s\n\007New mail for %s@%.*s\007 has arrived:%s\n----%s\n",
            cr, name, sizeof (hostname), hostname, cr, cr);
        jkfprintf(tp, name, offset);
        fclose(tp);
        _exit(0);
}

jkfprintf(tp, name, offset)
        register FILE *tp;
        char name[];
        off_t offset;
{
        register char *cp;
        register FILE *fi;
        register int linecnt, charcnt, inheader;
        char line[BUFSIZ];
        off_t fseek();

        if ((fi = fopen(name, "r")) == NULL)
                return;
        (void)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) {
                if (inheader) {
                        if (line[0] == '\n') {
                                inheader = 0;
                                continue;
                        }
                        if (line[0] == ' ' || line[0] == '\t' ||
                            strncmp(line, "From:", 5) &&
                            strncmp(line, "Subject:", 8))
                                continue;
                }
                if (linecnt <= 0 || charcnt <= 0) {
                        fprintf(tp, "...more...%s\n", cr);
                        return;
                }
                if (cp = index(line, '\n'))
                        *cp = '\0';
                fprintf(tp, "%s%s\n", line, cr);
                charcnt -= strlen(line);
                linecnt--;
        }
        fprintf(tp, "----%s\n", cr);
}