usr.bin/finger/net.c

   1 /*
   2  * Copyright (c) 1989, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Tony Nardo of the Johns Hopkins University/Applied Physics Lab.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  *
  36  * @(#)net.c    8.4 (Berkeley) 4/28/95
  37  * $FreeBSD: src/usr.bin/finger/net.c,v 1.12.2.4 2002/12/16 08:41:28 roam Exp $
  38  * $DragonFly: src/usr.bin/finger/net.c,v 1.5 2004/09/03 19:13:23 dillon Exp $
  39  */
  40
  41 #include <sys/param.h>
  42 #include <sys/socket.h>
  43 #include <sys/uio.h>
  44 #include <ctype.h>
  45 #include <db.h>
  46 #include <err.h>
  47 #include <netdb.h>
  48 #include <pwd.h>
  49 #include <stdio.h>
  50 #include <stdlib.h>
  51 #include <string.h>
  52 #include <unistd.h>
  53 #include <utmp.h>
  54 #include "finger.h"
  55
  56 static void cleanup(int sig);
  57 static int do_protocol(const char *name, const struct addrinfo *ai);
  58 static void trying(const struct addrinfo *ai);
  59
  60 void
  61 netfinger(char *name)
  62 {
  63         int error, multi;
  64         char *host;
  65         struct addrinfo *ai, *ai0;
  66         static struct addrinfo hint;
  67
  68         host = strrchr(name, '@');
  69         if (host == 0)
  70                 return;
  71         *host++ = '\0';
  72         signal(SIGALRM, cleanup);
  73         alarm(TIME_LIMIT);
  74
  75         hint.ai_flags = AI_CANONNAME;
  76         hint.ai_family = family;
  77         hint.ai_socktype = SOCK_STREAM;
  78
  79         error = getaddrinfo(host, "finger", &hint, &ai0);
  80         if (error) {
  81                 warnx("%s: %s", host, gai_strerror(error));
  82                 return;
  83         }
  84
  85         multi = (ai0->ai_next) != 0;
  86
  87         /* ai_canonname may not be filled in if the user specified an IP. */
  88         if (ai0->ai_canonname == 0)
  89                 printf("[%s]\n", host);
  90         else
  91                 printf("[%s]\n", ai0->ai_canonname);
  92
  93         for (ai = ai0; ai != 0; ai = ai->ai_next) {
  94                 if (multi)
  95                         trying(ai);
  96
  97                 error = do_protocol(name, ai);
  98                 if (!error)
  99                         break;
 100         }
 101         alarm(0);
 102         freeaddrinfo(ai0);
 103 }
 104
 105 static int
 106 do_protocol(const char *name, const struct addrinfo *ai)
 107 {
 108         int cnt, line_len, s;
 109         FILE *fp;
 110         int c, lastc;
 111         struct iovec iov[3];
 112         struct msghdr msg;
 113         static char slash_w[] = "/W ";
 114         static char neteol[] = "\r\n";
 115
 116         s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 117         if (s < 0) {
 118                 warn("socket(%d, %d, %d)", ai->ai_family, ai->ai_socktype,
 119                      ai->ai_protocol);
 120                 return -1;
 121         }
 122
 123         msg.msg_name = (void *)ai->ai_addr;
 124         msg.msg_namelen = ai->ai_addrlen;
 125         msg.msg_iov = iov;
 126         msg.msg_iovlen = 0;
 127         msg.msg_control = 0;
 128         msg.msg_controllen = 0;
 129         msg.msg_flags = 0;
 130
 131         /* -l flag for remote fingerd  */
 132         if (lflag) {
 133                 iov[msg.msg_iovlen].iov_base = slash_w;
 134                 iov[msg.msg_iovlen++].iov_len = 3;
 135         }
 136         /* send the name followed by <CR><LF> */
 137         iov[msg.msg_iovlen].iov_base = strdup(name);
 138         iov[msg.msg_iovlen++].iov_len = strlen(name);
 139         iov[msg.msg_iovlen].iov_base = neteol;
 140         iov[msg.msg_iovlen++].iov_len = 2;
 141
 142         /*
 143          * -T disables data-on-SYN: compatibility option to finger broken
 144          * hosts.  Also, the implicit-open API is broken on IPv6, so do
 145          * the explicit connect there, too.
 146          */
 147         if ((Tflag || ai->ai_addr->sa_family == AF_INET6)
 148             && connect(s, ai->ai_addr, ai->ai_addrlen) < 0) {
 149                 warn("connect");
 150                 close(s);
 151                 return -1;
 152         }
 153
 154         if (sendmsg(s, &msg, 0) < 0) {
 155                 warn("sendmsg");
 156                 close(s);
 157                 return -1;
 158         }
 159
 160         /*
 161          * Read from the remote system; once we're connected, we assume some
 162          * data.  If none arrives, we hang until the user interrupts.
 163          *
 164          * If we see a <CR> or a <CR> with the high bit set, treat it as
 165          * a newline; if followed by a newline character, only output one
 166          * newline.
 167          *
 168          * Otherwise, all high bits are stripped; if it isn't printable and
 169          * it isn't a space, we can simply set the 7th bit.  Every ASCII
 170          * character with bit 7 set is printable.
 171          */
 172         lastc = 0;
 173         if ((fp = fdopen(s, "r")) != NULL) {
 174                 cnt = 0;
 175                 line_len = 0;
 176                 while ((c = getc(fp)) != EOF) {
 177                         if (++cnt > OUTPUT_MAX) {
 178                                 printf("\n\n Output truncated at %d bytes...\n",
 179                                         cnt - 1);
 180                                 break;
 181                         }
 182                         if (c == 0x0d) {
 183                                 if (lastc == '\r')      /* ^M^M - skip dupes */
 184                                         continue;
 185                                 c = '\n';
 186                                 lastc = '\r';
 187                         } else {
 188                                 if (!(eightflag || isprint(c) || isspace(c))) {
 189                                         c &= 0x7f;
 190                                         c |= 0x40;
 191                                 }
 192                                 if (lastc != '\r' || c != '\n')
 193                                         lastc = c;
 194                                 else {
 195                                         lastc = '\n';
 196                                         continue;
 197                                 }
 198                         }
 199                         putchar(c);
 200                         if (c != '\n' && ++line_len > _POSIX2_LINE_MAX) {
 201                                 putchar('\\');
 202                                 putchar('\n');
 203                                 lastc = '\r';
 204                         }
 205                         if (lastc == '\n' || lastc == '\r')
 206                                 line_len = 0;
 207                 }
 208                 if (ferror(fp)) {
 209                         /*
 210                          * Assume that whatever it was set errno...
 211                          */
 212                         warn("reading from network");
 213                 }
 214                 if (lastc != '\n')
 215                         putchar('\n');
 216
 217                 fclose(fp);
 218         }
 219         return 0;
 220 }
 221
 222 static void
 223 trying(const struct addrinfo *ai)
 224 {
 225         char buf[NI_MAXHOST];
 226
 227         if (getnameinfo(ai->ai_addr, ai->ai_addrlen, buf, sizeof buf,
 228                         NULL, 0, NI_NUMERICHOST) != 0)
 229                 return;         /* XXX can't happen */
 230
 231         printf("Trying %s...\n", buf);
 232 }
 233
 234 void
 235 cleanup(int sig __unused)
 236 {
 237 #define ERRSTR  "Timed out.\n"
 238         write(STDERR_FILENO, ERRSTR, sizeof ERRSTR);
 239         exit(1);
 240 }
 241