1 #ifndef lint 2 static char *sccsid = "@(#)comsat.c 4.5 82/12/23"; 3 #endif 4 5 #include <sys/types.h> 6 #include <sys/socket.h> 7 8 #include <netinet/in.h> 9 10 #include <stdio.h> 11 #include <sgtty.h> 12 #include <utmp.h> 13 #include <stat.h> 14 #include <wait.h> 15 #include <signal.h> 16 #include <errno.h> 17 #include <netdb.h> 18 19 /* 20 * comsat 21 */ 22 #define dprintf if (0) printf 23 24 #define MAXUTMP 100 /* down from init */ 25 26 struct sockaddr_in sin = { AF_INET }; 27 extern errno; 28 29 struct utmp utmp[100]; 30 int nutmp; 31 int uf; 32 unsigned utmpmtime; /* last modification time for utmp */ 33 int onalrm(); 34 struct servent *sp; 35 36 #define NAMLEN (sizeof (uts[0].ut_name) + 1) 37 38 main(argc, argv) 39 char **argv; 40 { 41 register cc; 42 char buf[BUFSIZ]; 43 int s; 44 45 sp = getservbyname("biff", "udp"); 46 if (sp == 0) { 47 fprintf(stderr, "comsat: biff/udp: unknown service\n"); 48 exit(1); 49 } 50 #ifndef DEBUG 51 if (fork()) 52 exit(); 53 #endif 54 chdir("/usr/spool/mail"); 55 if((uf = open("/etc/utmp",0)) < 0) 56 perror("/etc/utmp"), exit(1); 57 #ifndef DEBUG 58 while (fork()) 59 wait(0); 60 #endif 61 sleep(10); 62 onalrm(); 63 sigset(SIGALRM, onalrm); 64 sigignore(SIGTTOU); 65 s = socket(AF_INET, SOCK_DGRAM, 0, 0); 66 if (s < 0) { 67 perror("socket"); 68 exit(1); 69 } 70 sin.sin_port = sp->s_port; 71 if (bind(s, &sin, sizeof (sin), 0) < 0) { 72 perror("bind"); 73 exit(1); 74 } 75 for (;;) { 76 char msgbuf[100]; 77 int cc; 78 79 cc = recv(s, msgbuf, sizeof (msgbuf) - 1, 0); 80 if (cc <= 0) { 81 if (errno != EINTR) 82 sleep(1); 83 errno = 0; 84 continue; 85 } 86 msgbuf[cc] = 0; 87 mailfor(msgbuf); 88 } 89 } 90 91 onalrm() 92 { 93 struct stat statbf; 94 struct utmp *utp; 95 96 dprintf("alarm\n"); 97 alarm(15); 98 fstat(uf,&statbf); 99 if (statbf.st_mtime > utmpmtime) { 100 dprintf(" changed\n"); 101 utmpmtime = statbf.st_mtime; 102 lseek(uf, 0, 0); 103 nutmp = read(uf,utmp,sizeof(utmp))/sizeof(struct utmp); 104 } else 105 dprintf(" ok\n"); 106 } 107 108 mailfor(name) 109 char *name; 110 { 111 register struct utmp *utp = &utmp[nutmp]; 112 register char *cp; 113 char *rindex(); 114 int offset; 115 116 dprintf("mailfor %s\n", name); 117 cp = name; 118 while (*cp && *cp != '@') 119 cp++; 120 if (*cp == 0) { 121 dprintf("bad format\n"); 122 return; 123 } 124 *cp = 0; 125 offset = atoi(cp+1); 126 while (--utp >= utmp) 127 if (!strncmp(utp->ut_name, name, sizeof(utmp[0].ut_name))) 128 if (fork() == 0) { 129 signal(SIGALRM, SIG_DFL); 130 alarm(30); 131 notify(utp, offset), exit(0); 132 } else 133 while (wait3(0, WNOHANG, 0) > 0) 134 continue; 135 } 136 137 char *cr; 138 139 notify(utp, offset) 140 register struct utmp *utp; 141 { 142 FILE *tp; 143 struct sgttyb gttybuf; 144 char tty[20]; 145 char name[sizeof (utmp[0].ut_name) + 1]; 146 struct stat stb; 147 148 strcpy(tty, "/dev/"); 149 strncat(tty, utp->ut_line, sizeof(utp->ut_line)); 150 dprintf("notify %s on %s\n", utp->ut_name, tty); 151 if (stat(tty, &stb) == 0 && (stb.st_mode & 0100) == 0) { 152 dprintf("wrong mode\n"); 153 return; 154 } 155 if ((tp = fopen(tty,"w")) == 0) { 156 dprintf("fopen failed\n"); 157 return; 158 } 159 gtty(fileno(tp),>tybuf); 160 cr = (gttybuf.sg_flags & CRMOD) ? "" : "\r"; 161 strncpy(name, utp->ut_name, sizeof (utp->ut_name)); 162 name[sizeof (name) - 1] = 0; 163 fprintf(tp,"%s\n\007New mail for %s\007 has arrived:%s\n", 164 cr, name, cr); 165 fprintf(tp,"----%s\n", cr); 166 jkfprintf(tp, name, offset); 167 fclose(tp); 168 } 169 170 jkfprintf(tp, name, offset) 171 register FILE *tp; 172 { 173 register FILE *fi; 174 register int linecnt, charcnt; 175 176 dprintf("HERE %s's mail starting at %d\n", 177 name, offset); 178 if ((fi = fopen(name,"r")) == NULL) { 179 dprintf("Cant read the mail\n"); 180 return; 181 } 182 fseek(fi, offset, 0); 183 linecnt = 7; 184 charcnt = 560; 185 /* 186 * print the first 7 lines or 560 characters of the new mail 187 * (whichever comes first) 188 */ 189 for (;;) { 190 register ch; 191 192 if ((ch = getc(fi)) == EOF) { 193 fprintf(tp,"----%s\n", cr); 194 break; 195 } 196 if (ch == '\n') { 197 fprintf(tp,"%s\n", cr); 198 if (linecnt-- < 0) { 199 fprintf(tp,"...more...%s\n", cr); 200 break; 201 } 202 } else if(linecnt <= 0) { 203 fprintf(tp,"...more...%s\n", cr); 204 break; 205 } else 206 putc(ch, tp); 207 if (charcnt-- == 0) { 208 fprintf(tp, "%s\n", cr); 209 break; 210 } 211 } 212 } 213