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