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 "finger.h"
  49
  50 static void cleanup(int sig);
  51 static int do_protocol(const char *name, const struct addrinfo *ai);
  52 static void trying(const struct addrinfo *ai);
  53
  54 void
  55 netfinger(char *name)
  56 {
  57         int error, multi;
  58         char *host;
  59         struct addrinfo *ai, *ai0;
  60         static struct addrinfo hint;
  61
  62         host = strrchr(name, '@');
  63         if (host == NULL)
  64                 return;
  65         *host++ = '\0';
  66         signal(SIGALRM, cleanup);
  67         alarm(TIME_LIMIT);
  68
  69         hint.ai_flags = AI_CANONNAME;
  70         hint.ai_family = family;
  71         hint.ai_socktype = SOCK_STREAM;
  72
  73         error = getaddrinfo(host, "finger", &hint, &ai0);
  74         if (error) {
  75                 warnx("%s: %s", host, gai_strerror(error));
  76                 return;
  77         }
  78
  79         multi = (ai0->ai_next) != 0;
  80
  81         /* ai_canonname may not be filled in if the user specified an IP. */
  82         if (ai0->ai_canonname == 0)
  83                 printf("[%s]\n", host);
  84         else
  85                 printf("[%s]\n", ai0->ai_canonname);
  86
  87         for (ai = ai0; ai != NULL; ai = ai->ai_next) {
  88                 if (multi)
  89                         trying(ai);
  90
  91                 error = do_protocol(name, ai);
  92                 if (!error)
  93                         break;
  94         }
  95         alarm(0);
  96         freeaddrinfo(ai0);
  97 }
  98
  99 static int
 100 do_protocol(const char *name, const struct addrinfo *ai)
 101 {
 102         int cnt, line_len, s;
 103         FILE *fp;
 104         int c, lastc;
 105         struct iovec iov[3];
 106         struct msghdr msg;
 107         static char slash_w[] = "/W ";
 108         static char neteol[] = "\r\n";
 109
 110         s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 111         if (s < 0) {
 112                 warn("socket(%d, %d, %d)", ai->ai_family, ai->ai_socktype,
 113                      ai->ai_protocol);
 114                 return -1;
 115         }
 116
 117         msg.msg_name = (void *)ai->ai_addr;
 118         msg.msg_namelen = ai->ai_addrlen;
 119         msg.msg_iov = iov;
 120         msg.msg_iovlen = 0;
 121         msg.msg_control = 0;
 122         msg.msg_controllen = 0;
 123         msg.msg_flags = 0;
 124
 125         /* -l flag for remote fingerd  */
 126         if (lflag) {
 127                 iov[msg.msg_iovlen].iov_base = slash_w;
 128                 iov[msg.msg_iovlen++].iov_len = 3;
 129         }
 130         /* send the name followed by <CR><LF> */
 131         iov[msg.msg_iovlen].iov_base = strdup(name);
 132         iov[msg.msg_iovlen++].iov_len = strlen(name);
 133         iov[msg.msg_iovlen].iov_base = neteol;
 134         iov[msg.msg_iovlen++].iov_len = 2;
 135
 136         /*
 137          * -T disables data-on-SYN: compatibility option to finger broken
 138          * hosts.  Also, the implicit-open API is broken on IPv6, so do
 139          * the explicit connect there, too.
 140          */
 141         if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0) {
 142                 warn("connect");
 143                 close(s);
 144                 return -1;
 145         }
 146
 147         if (sendmsg(s, &msg, 0) < 0) {
 148                 warn("sendmsg");
 149                 close(s);
 150                 return -1;
 151         }
 152
 153         /*
 154          * Read from the remote system; once we're connected, we assume some
 155          * data.  If none arrives, we hang until the user interrupts.
 156          *
 157          * If we see a <CR> or a <CR> with the high bit set, treat it as
 158          * a newline; if followed by a newline character, only output one
 159          * newline.
 160          *
 161          * Otherwise, all high bits are stripped; if it isn't printable and
 162          * it isn't a space, we can simply set the 7th bit.  Every ASCII
 163          * character with bit 7 set is printable.
 164          */
 165         lastc = 0;
 166         if ((fp = fdopen(s, "r")) != NULL) {
 167                 cnt = 0;
 168                 line_len = 0;
 169                 while ((c = getc(fp)) != EOF) {
 170                         if (++cnt > OUTPUT_MAX) {
 171                                 printf("\n\n Output truncated at %d bytes...\n",
 172                                         cnt - 1);
 173                                 break;
 174                         }
 175                         if (c == 0x0d) {
 176                                 if (lastc == '\r')      /* ^M^M - skip dupes */
 177                                         continue;
 178                                 c = '\n';
 179                                 lastc = '\r';
 180                         } else {
 181                                 if (!(eightflag || isprint(c) || isspace(c))) {
 182                                         c &= 0x7f;
 183                                         c |= 0x40;
 184                                 }
 185                                 if (lastc != '\r' || c != '\n')
 186                                         lastc = c;
 187                                 else {
 188                                         lastc = '\n';
 189                                         continue;
 190                                 }
 191                         }
 192                         putchar(c);
 193                         if (c != '\n' && ++line_len > _POSIX2_LINE_MAX) {
 194                                 putchar('\\');
 195                                 putchar('\n');
 196                                 lastc = '\r';
 197                         }
 198                         if (lastc == '\n' || lastc == '\r')
 199                                 line_len = 0;
 200                 }
 201                 if (ferror(fp)) {
 202                         /*
 203                          * Assume that whatever it was set errno...
 204                          */
 205                         warn("reading from network");
 206                 }
 207                 if (lastc != '\n')
 208                         putchar('\n');
 209
 210                 fclose(fp);
 211         }
 212         return 0;
 213 }
 214
 215 static void
 216 trying(const struct addrinfo *ai)
 217 {
 218         char buf[NI_MAXHOST];
 219
 220         if (getnameinfo(ai->ai_addr, ai->ai_addrlen, buf, sizeof buf,
 221                         NULL, 0, NI_NUMERICHOST) != 0)
 222                 return;         /* XXX can't happen */
 223
 224         printf("Trying %s...\n", buf);
 225 }
 226
 227 void
 228 cleanup(int sig __unused)
 229 {
 230 #define ERRSTR  "Timed out.\n"
 231         write(STDERR_FILENO, ERRSTR, sizeof ERRSTR);
 232         exit(1);
 233 }
 234