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 extern int lflag;               /* XXX finger.h? */
  57 extern int Tflag;               /* XXX finger.h? */
  58 extern sa_family_t family;
  59
  60 static void cleanup(int sig);
  61 static int do_protocol(const char *name, const struct addrinfo *ai);
  62 static void trying(const struct addrinfo *ai);
  63
  64 void
  65 netfinger(char *name)
  66 {
  67         int error, multi;
  68         char *host;
  69         struct addrinfo *ai, *ai0;
  70         static struct addrinfo hint;
  71
  72         host = strrchr(name, '@');
  73         if (host == 0)
  74                 return;
  75         *host++ = '\0';
  76         signal(SIGALRM, cleanup);
  77         alarm(TIME_LIMIT);
  78
  79         hint.ai_flags = AI_CANONNAME;
  80         hint.ai_family = family;
  81         hint.ai_socktype = SOCK_STREAM;
  82
  83         error = getaddrinfo(host, "finger", &hint, &ai0);
  84         if (error) {
  85                 warnx("%s: %s", host, gai_strerror(error));
  86                 return;
  87         }
  88
  89         multi = (ai0->ai_next) != 0;
  90
  91         /* ai_canonname may not be filled in if the user specified an IP. */
  92         if (ai0->ai_canonname == 0)
  93                 printf("[%s]\n", host);
  94         else
  95                 printf("[%s]\n", ai0->ai_canonname);
  96
  97         for (ai = ai0; ai != 0; ai = ai->ai_next) {
  98                 if (multi)
  99                         trying(ai);
 100
 101                 error = do_protocol(name, ai);
 102                 if (!error)
 103                         break;
 104         }
 105         alarm(0);
 106         freeaddrinfo(ai0);
 107 }
 108
 109 static int
 110 do_protocol(const char *name, const struct addrinfo *ai)
 111 {
 112         int cnt, line_len, s;
 113         FILE *fp;
 114         int c, lastc;
 115         struct iovec iov[3];
 116         struct msghdr msg;
 117         static char slash_w[] = "/W ";
 118         static char neteol[] = "\r\n";
 119
 120         s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 121         if (s < 0) {
 122                 warn("socket(%d, %d, %d)", ai->ai_family, ai->ai_socktype,
 123                      ai->ai_protocol);
 124                 return -1;
 125         }
 126
 127         msg.msg_name = (void *)ai->ai_addr;
 128         msg.msg_namelen = ai->ai_addrlen;
 129         msg.msg_iov = iov;
 130         msg.msg_iovlen = 0;
 131         msg.msg_control = 0;
 132         msg.msg_controllen = 0;
 133         msg.msg_flags = 0;
 134
 135         /* -l flag for remote fingerd  */
 136         if (lflag) {
 137                 iov[msg.msg_iovlen].iov_base = slash_w;
 138                 iov[msg.msg_iovlen++].iov_len = 3;
 139         }
 140         /* send the name followed by <CR><LF> */
 141         iov[msg.msg_iovlen].iov_base = strdup(name);
 142         iov[msg.msg_iovlen++].iov_len = strlen(name);
 143         iov[msg.msg_iovlen].iov_base = neteol;
 144         iov[msg.msg_iovlen++].iov_len = 2;
 145
 146         /*
 147          * -T disables data-on-SYN: compatibility option to finger broken
 148          * hosts.  Also, the implicit-open API is broken on IPv6, so do
 149          * the explicit connect there, too.
 150          */
 151         if ((Tflag || ai->ai_addr->sa_family == AF_INET6)
 152             && connect(s, ai->ai_addr, ai->ai_addrlen) < 0) {
 153                 warn("connect");
 154                 close(s);
 155                 return -1;
 156         }
 157
 158         if (sendmsg(s, &msg, 0) < 0) {
 159                 warn("sendmsg");
 160                 close(s);
 161                 return -1;
 162         }
 163
 164         /*
 165          * Read from the remote system; once we're connected, we assume some
 166          * data.  If none arrives, we hang until the user interrupts.
 167          *
 168          * If we see a <CR> or a <CR> with the high bit set, treat it as
 169          * a newline; if followed by a newline character, only output one
 170          * newline.
 171          *
 172          * Otherwise, all high bits are stripped; if it isn't printable and
 173          * it isn't a space, we can simply set the 7th bit.  Every ASCII
 174          * character with bit 7 set is printable.
 175          */
 176         lastc = 0;
 177         if ((fp = fdopen(s, "r")) != NULL) {
 178                 cnt = 0;
 179                 line_len = 0;
 180                 while ((c = getc(fp)) != EOF) {
 181                         if (++cnt > OUTPUT_MAX) {
 182                                 printf("\n\n Output truncated at %d bytes...\n",
 183                                         cnt - 1);
 184                                 break;
 185                         }
 186                         if (c == 0x0d) {
 187                                 if (lastc == '\r')      /* ^M^M - skip dupes */
 188                                         continue;
 189                                 c = '\n';
 190                                 lastc = '\r';
 191                         } else {
 192                                 if (!(eightflag || isprint(c) || isspace(c))) {
 193                                         c &= 0x7f;
 194                                         c |= 0x40;
 195                                 }
 196                                 if (lastc != '\r' || c != '\n')
 197                                         lastc = c;
 198                                 else {
 199                                         lastc = '\n';
 200                                         continue;
 201                                 }
 202                         }
 203                         putchar(c);
 204                         if (c != '\n' && ++line_len > _POSIX2_LINE_MAX) {
 205                                 putchar('\\');
 206                                 putchar('\n');
 207                                 lastc = '\r';
 208                         }
 209                         if (lastc == '\n' || lastc == '\r')
 210                                 line_len = 0;
 211                 }
 212                 if (ferror(fp)) {
 213                         /*
 214                          * Assume that whatever it was set errno...
 215                          */
 216                         warn("reading from network");
 217                 }
 218                 if (lastc != '\n')
 219                         putchar('\n');
 220
 221                 fclose(fp);
 222         }
 223         return 0;
 224 }
 225
 226 static void
 227 trying(const struct addrinfo *ai)
 228 {
 229         char buf[NI_MAXHOST];
 230
 231         if (getnameinfo(ai->ai_addr, ai->ai_addrlen, buf, sizeof buf,
 232                         (char *)0, 0, NI_NUMERICHOST) != 0)
 233                 return;         /* XXX can't happen */
 234
 235         printf("Trying %s...\n", buf);
 236 }
 237
 238 void
 239 cleanup(int sig __unused)
 240 {
 241 #define ERRSTR  "Timed out.\n"
 242         write(STDERR_FILENO, ERRSTR, sizeof ERRSTR);
 243         exit(1);
 244 }
 245