#ifndef lint static char *sccsid = "@(#)comsat.c 4.5 82/12/23"; #endif #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <stdio.h> #include <sgtty.h> #include <utmp.h> #include <stat.h> #include <wait.h> #include <signal.h> #include <errno.h> #include <netdb.h> /* * comsat */ #define dprintf if (0) printf #define MAXUTMP 100 /* down from init */ struct sockaddr_in sin = { AF_INET }; extern errno; struct utmp utmp[100]; int nutmp; int uf; unsigned utmpmtime; /* last modification time for utmp */ int onalrm(); struct servent *sp; #define NAMLEN (sizeof (uts[0].ut_name) + 1) main(argc, argv) char **argv; { register cc; char buf[BUFSIZ]; int s; sp = getservbyname("biff", "udp"); if (sp == 0) { fprintf(stderr, "comsat: biff/udp: unknown service\n"); exit(1); } #ifndef DEBUG if (fork()) exit(); #endif chdir("/usr/spool/mail"); if((uf = open("/etc/utmp",0)) < 0) perror("/etc/utmp"), exit(1); #ifndef DEBUG while (fork()) wait(0); #endif sleep(10); onalrm(); sigset(SIGALRM, onalrm); sigignore(SIGTTOU); s = socket(AF_INET, SOCK_DGRAM, 0, 0); if (s < 0) { perror("socket"); exit(1); } sin.sin_port = sp->s_port; if (bind(s, &sin, sizeof (sin), 0) < 0) { perror("bind"); exit(1); } for (;;) { char msgbuf[100]; int cc; cc = recv(s, msgbuf, sizeof (msgbuf) - 1, 0); if (cc <= 0) { if (errno != EINTR) sleep(1); errno = 0; continue; } msgbuf[cc] = 0; mailfor(msgbuf); } } onalrm() { struct stat statbf; struct utmp *utp; dprintf("alarm\n"); alarm(15); fstat(uf,&statbf); if (statbf.st_mtime > utmpmtime) { dprintf(" changed\n"); utmpmtime = statbf.st_mtime; lseek(uf, 0, 0); nutmp = read(uf,utmp,sizeof(utmp))/sizeof(struct utmp); } else dprintf(" ok\n"); } mailfor(name) char *name; { register struct utmp *utp = &utmp[nutmp]; register char *cp; char *rindex(); int offset; dprintf("mailfor %s\n", name); cp = name; while (*cp && *cp != '@') cp++; if (*cp == 0) { dprintf("bad format\n"); return; } *cp = 0; offset = atoi(cp+1); while (--utp >= utmp) if (!strncmp(utp->ut_name, name, sizeof(utmp[0].ut_name))) if (fork() == 0) { signal(SIGALRM, SIG_DFL); alarm(30); notify(utp, offset), exit(0); } else while (wait3(0, WNOHANG, 0) > 0) continue; } char *cr; notify(utp, offset) register struct utmp *utp; { FILE *tp; struct sgttyb gttybuf; char tty[20]; char name[sizeof (utmp[0].ut_name) + 1]; struct stat stb; strcpy(tty, "/dev/"); strncat(tty, utp->ut_line, sizeof(utp->ut_line)); dprintf("notify %s on %s\n", utp->ut_name, tty); if (stat(tty, &stb) == 0 && (stb.st_mode & 0100) == 0) { dprintf("wrong mode\n"); return; } if ((tp = fopen(tty,"w")) == 0) { dprintf("fopen failed\n"); return; } gtty(fileno(tp),>tybuf); cr = (gttybuf.sg_flags & CRMOD) ? "" : "\r"; strncpy(name, utp->ut_name, sizeof (utp->ut_name)); name[sizeof (name) - 1] = 0; fprintf(tp,"%s\n\007New mail for %s\007 has arrived:%s\n", cr, name, cr); fprintf(tp,"----%s\n", cr); jkfprintf(tp, name, offset); fclose(tp); } jkfprintf(tp, name, offset) register FILE *tp; { register FILE *fi; register int linecnt, charcnt; dprintf("HERE %s's mail starting at %d\n", name, offset); if ((fi = fopen(name,"r")) == NULL) { dprintf("Cant read the mail\n"); return; } fseek(fi, offset, 0); linecnt = 7; charcnt = 560; /* * print the first 7 lines or 560 characters of the new mail * (whichever comes first) */ for (;;) { register ch; if ((ch = getc(fi)) == EOF) { fprintf(tp,"----%s\n", cr); break; } if (ch == '\n') { fprintf(tp,"%s\n", cr); if (linecnt-- < 0) { fprintf(tp,"...more...%s\n", cr); break; } } else if(linecnt <= 0) { fprintf(tp,"...more...%s\n", cr); break; } else putc(ch, tp); if (charcnt-- == 0) { fprintf(tp, "%s\n", cr); break; } } }