adv_cmds/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
  37 #if 0
  38 #ifndef lint
  39 static char sccsid[] = "@(#)net.c       8.4 (Berkeley) 4/28/95";
  40 #endif
  41 #endif
  42
  43 #include <sys/cdefs.h>
  44 __FBSDID("$FreeBSD: src/usr.bin/finger/net.c,v 1.23 2004/05/16 22:08:15 stefanf Exp $");
  45
  46 #include <sys/param.h>
  47 #include <sys/socket.h>
  48 #include <sys/uio.h>
  49 #include <ctype.h>
  50 #include <db.h>
  51 #include <err.h>
  52 #include <netdb.h>
  53 #include <pwd.h>
  54 #include <stdio.h>
  55 #include <stdlib.h>
  56 #include <string.h>
  57 #include <unistd.h>
  58 #include <utmpx.h>
  59 #include "finger.h"
  60
  61 static void cleanup(int sig);
  62 static int do_protocol(const char *name, const struct addrinfo *ai);
  63 static void trying(const struct addrinfo *ai);
  64
  65 void
  66 netfinger(char *name)
  67 {
  68         int error, multi;
  69         char *host;
  70         struct addrinfo *ai, *ai0;
  71         static struct addrinfo hint;
  72
  73         host = strrchr(name, '@');
  74         if (host == 0)
  75                 return;
  76         *host++ = '\0';
  77         signal(SIGALRM, cleanup);
  78         alarm(TIME_LIMIT);
  79
  80         hint.ai_flags = AI_CANONNAME;
  81         hint.ai_family = family;
  82         hint.ai_socktype = SOCK_STREAM;
  83
  84         error = getaddrinfo(host, "finger", &hint, &ai0);
  85         if (error) {
  86                 warnx("%s: %s", host, gai_strerror(error));
  87                 return;
  88         }
  89
  90         multi = (ai0->ai_next) != 0;
  91
  92         /* ai_canonname may not be filled in if the user specified an IP. */
  93         if (ai0->ai_canonname == 0)
  94                 printf("[%s]\n", host);
  95         else
  96                 printf("[%s]\n", ai0->ai_canonname);
  97
  98         for (ai = ai0; ai != 0; ai = ai->ai_next) {
  99                 if (multi)
 100                         trying(ai);
 101
 102                 error = do_protocol(name, ai);
 103                 if (!error)
 104                         break;
 105         }
 106         alarm(0);
 107         freeaddrinfo(ai0);
 108 }
 109
 110 static int
 111 do_protocol(const char *name, const struct addrinfo *ai)
 112 {
 113         int cnt, line_len, s;
 114         FILE *fp;
 115         int c, lastc;
 116         struct iovec iov[3];
 117         struct msghdr msg;
 118         static char slash_w[] = "/W ";
 119         static char neteol[] = "\r\n";
 120
 121         s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 122         if (s < 0) {
 123                 warn("socket(%d, %d, %d)", ai->ai_family, ai->ai_socktype,
 124                      ai->ai_protocol);
 125                 return -1;
 126         }
 127
 128         msg.msg_name = (void *)ai->ai_addr;
 129         msg.msg_namelen = ai->ai_addrlen;
 130         msg.msg_iov = iov;
 131         msg.msg_iovlen = 0;
 132         msg.msg_control = 0;
 133         msg.msg_controllen = 0;
 134         msg.msg_flags = 0;
 135
 136         /* -l flag for remote fingerd  */
 137         if (lflag) {
 138                 iov[msg.msg_iovlen].iov_base = slash_w;
 139                 iov[msg.msg_iovlen++].iov_len = 3;
 140         }
 141         /* send the name followed by <CR><LF> */
 142         iov[msg.msg_iovlen].iov_base = strdup(name);
 143         iov[msg.msg_iovlen++].iov_len = strlen(name);
 144         iov[msg.msg_iovlen].iov_base = neteol;
 145         iov[msg.msg_iovlen++].iov_len = 2;
 146
 147 #ifdef __APPLE__
 148         if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0) {
 149 #else
 150         /*
 151          * -T disables data-on-SYN: compatibility option to finger broken
 152          * hosts.  Also, the implicit-open API is broken on IPv6, so do
 153          * the explicit connect there, too.
 154          */
 155         if ((Tflag || ai->ai_addr->sa_family == AF_INET6)
 156             && connect(s, ai->ai_addr, ai->ai_addrlen) < 0) {
 157 #endif
 158                 warn("connect");
 159                 close(s);
 160                 return -1;
 161         }
 162
 163         if (sendmsg(s, &msg, 0) < 0) {
 164                 warn("sendmsg");
 165                 close(s);
 166                 return -1;
 167         }
 168
 169         /*
 170          * Read from the remote system; once we're connected, we assume some
 171          * data.  If none arrives, we hang until the user interrupts.
 172          *
 173          * If we see a <CR> or a <CR> with the high bit set, treat it as
 174          * a newline; if followed by a newline character, only output one
 175          * newline.
 176          *
 177          * Otherwise, all high bits are stripped; if it isn't printable and
 178          * it isn't a space, we can simply set the 7th bit.  Every ASCII
 179          * character with bit 7 set is printable.
 180          */
 181         lastc = 0;
 182         if ((fp = fdopen(s, "r")) != NULL) {
 183                 cnt = 0;
 184                 line_len = 0;
 185                 while ((c = getc(fp)) != EOF) {
 186                         if (++cnt > OUTPUT_MAX) {
 187                                 printf("\n\n Output truncated at %d bytes...\n",
 188                                         cnt - 1);
 189                                 break;
 190                         }
 191                         if (c == 0x0d) {
 192                                 if (lastc == '\r')      /* ^M^M - skip dupes */
 193                                         continue;
 194                                 c = '\n';
 195                                 lastc = '\r';
 196                         } else {
 197                                 if (!isprint(c) && !isspace(c)) {
 198                                         c &= 0x7f;
 199                                         c |= 0x40;
 200                                 }
 201                                 if (lastc != '\r' || c != '\n')
 202                                         lastc = c;
 203                                 else {
 204                                         lastc = '\n';
 205                                         continue;
 206                                 }
 207                         }
 208                         putchar(c);
 209                         if (c != '\n' && ++line_len > _POSIX2_LINE_MAX) {
 210                                 putchar('\\');
 211                                 putchar('\n');
 212                                 lastc = '\r';
 213                         }
 214                         if (lastc == '\n' || lastc == '\r')
 215                                 line_len = 0;
 216                 }
 217                 if (ferror(fp)) {
 218                         /*
 219                          * Assume that whatever it was set errno...
 220                          */
 221                         warn("reading from network");
 222                 }
 223                 if (lastc != '\n')
 224                         putchar('\n');
 225
 226                 fclose(fp);
 227         }
 228         return 0;
 229 }
 230
 231 static void
 232 trying(const struct addrinfo *ai)
 233 {
 234         char buf[NI_MAXHOST];
 235
 236         if (getnameinfo(ai->ai_addr, ai->ai_addrlen, buf, sizeof buf,
 237                         (char *)0, 0, NI_NUMERICHOST) != 0)
 238                 return;         /* XXX can't happen */
 239
 240         printf("Trying %s...\n", buf);
 241 }
 242
 243 void
 244 cleanup(int sig __unused)
 245 {
 246 #define ERRSTR  "Timed out.\n"
 247         write(STDERR_FILENO, ERRSTR, sizeof ERRSTR);
 248         exit(1);
 249 }
 250