296 lines
7.3 KiB
C
296 lines
7.3 KiB
C
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/*
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* Copyright (c) 1983 The Regents of the University of California.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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char copyright[] =
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"@(#) Copyright (c) 1983 The Regents of the University of California.\n"
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"All rights reserved.\n";
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/*
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* from: @(#)fingerd.c 5.6 (Berkeley) 6/1/90"
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*/
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char rcsid[] =
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"$Id: fingerd.c,v 1.23 1999/12/12 18:46:28 dholland Exp $";
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#include <pwd.h>
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#include <grp.h>
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#include <netdb.h>
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <signal.h>
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#include <syslog.h>
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#include <getopt.h>
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#include <netinet/in.h>
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#include <sys/utsname.h>
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#include <sys/wait.h>
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#include "pathnames.h"
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#include "../version.h"
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#define ENTRIES 50
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#define WS " \t\r\n"
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/* These are used in this order if the finger path compiled in doesn't work. */
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#define _ALT_PATH_FINGER_1 "/usr/local/bin/finger"
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#define _ALT_PATH_FINGER_2 "/usr/ucb/finger"
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#define _ALT_PATH_FINGER_3 "/usr/bin/finger"
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static
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void
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fatal(const char *msg, int use_errno, int tolog, int toclient)
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{
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const char *err = "";
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const char *sep = "";
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if (use_errno) {
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err = strerror(errno);
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sep = ": ";
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}
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if (tolog) syslog(LOG_ERR, "%s%s%s\n", msg, sep, err);
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if (toclient) fprintf(stderr, "fingerd: %s%s%s\r\n", msg, sep, err);
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else fprintf(stderr, "fingerd: Internal error\r\n");
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exit(1);
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}
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static
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void
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timeout(int sig)
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{
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(void)sig;
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errno = ETIMEDOUT;
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fatal("Input timeout", 0, 1, 1);
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}
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int
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main(int argc, char *argv[])
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{
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#if 0
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FILE *fp;
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int p[2], ch;
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pid_t pid;
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#endif
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int ca;
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const char *av[ENTRIES + 1];
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const char **avy;
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char *const *avx;
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char line[1024];
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int welcome = 0, heavylogging = 0, nouserlist = 0;
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int patience = 60, forwarding = 0;
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int k, nusers;
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char *s, *t;
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const char *fingerpath = NULL;
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struct sockaddr_in sn;
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socklen_t sval = sizeof(sn);
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if (getpeername(0, (struct sockaddr *) &sn, &sval) < 0) {
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fatal("getpeername", 1, 0, 1);
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}
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openlog("fingerd", LOG_PID, LOG_DAEMON);
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if (!getuid() || !geteuid()) {
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struct passwd *pwd = getpwnam("nobody");
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if (pwd) {
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initgroups(pwd->pw_name, pwd->pw_gid);
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setgid(pwd->pw_gid);
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setuid(pwd->pw_uid);
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}
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seteuid(0); /* this should fail */
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if (!getuid() || !geteuid()) {
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fatal("setuid: couldn't drop root", 0, 1, 0);
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}
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}
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/*endpwent(); -- is it safe to put this here? */
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opterr = 0;
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while ((ca = getopt(argc, argv, "wlL:p:uft:h?")) != EOF) {
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switch(ca) {
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case 'w':
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welcome = 1;
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break;
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case 'l':
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heavylogging = 1;
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break;
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case 'L':
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case 'p':
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fingerpath = optarg;
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break;
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case 'u':
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nouserlist = 1;
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break;
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case 'f':
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forwarding = 1;
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break;
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case 't':
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patience = atoi(optarg);
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break;
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case '?':
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case 'h':
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default:
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syslog(LOG_ERR, "usage: fingerd [-wulf]"
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"[-pL /path/finger] [-t timeout]");
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exit(1);
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}
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}
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argc -= optind;
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argv += optind;
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/*
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* Hang up after a while so people can't DoS by leaving lots of
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* open sockets about.
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*/
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if (patience != 0) {
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signal(SIGALRM, timeout);
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alarm(patience);
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}
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if (!fgets(line, sizeof(line), stdin)) {
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fatal("Client hung up - probable port-scan", 0, 1, 0);
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}
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if (welcome) {
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char buf[256];
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struct hostent *hp;
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struct utsname utsname;
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uname(&utsname);
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gethostname(buf, sizeof(buf));
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if ((hp = gethostbyname(buf))) {
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/* paranoia: dns spoofing? */
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strncpy(buf, hp->h_name, sizeof(buf));
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buf[sizeof(buf)-1] = 0;
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}
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printf("\r\nWelcome to %s version %s at %s !\r\n\n",
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utsname.sysname, utsname.release, buf);
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fflush(stdout);
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switch (fork()) {
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case -1: /* fork failed, oh well */
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break;
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case 0: /* child */
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execl(_PATH_UPTIME, _PATH_UPTIME, NULL);
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_exit(1);
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default: /* parent */
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wait(NULL);
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break;
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}
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fflush(stdout);
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printf("\r\n");
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fflush(stdout);
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}
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k = nusers = 0;
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av[k++] = "finger";
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for (s = strtok(line, WS); s && k<ENTRIES; s = strtok(NULL, WS)) {
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/* RFC742: "/[Ww]" == "-l" */
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if (!strncasecmp(s, "/w", 2)) memcpy(s, "-l", 2);
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if (!forwarding) {
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t = strchr(s, '@');
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if (t) {
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fprintf(stderr,
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"fingerd: forwarding not allowed\r\n");
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syslog(LOG_WARNING, "rejected %s\n", s);
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exit(1);
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}
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}
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if (heavylogging) {
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if (*s=='-') syslog(LOG_INFO, "option %s\n", s);
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else syslog(LOG_INFO, "fingered %s\n", s);
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}
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av[k++] = s;
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if (*s!='-') nusers++;
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}
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av[k] = NULL;
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if (nusers==0) {
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/* finger @host */
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if (nouserlist) {
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syslog(LOG_WARNING, "rejected finger @host\n");
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printf("Please supply a username\r\n");
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return 0;
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}
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if (heavylogging) syslog(LOG_INFO, "fingered @host\n");
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}
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/* Yay! we don't need to do this any more - finger does it for us */
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#if 0
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if (pipe(p) < 0) {
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fatal("pipe", 1, 1, 0);
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}
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pid = fork();
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if (pid<0) {
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fatal("fork", 1, 1, 0);
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}
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if (pid==0) {
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/* child */
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close(p[0]);
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dup2(p[1], 1);
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if (p[1]!=1) close(p[1]);
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#endif
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/*
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* execv() takes (char *const *), because (char const *const *)
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* doesn't work right in C (only in C++). C9x might fix this
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* if we're lucky. In the meantime we need to defeat the type
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* system to avoid warnings.
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*/
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avy = av;
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/*avx = avy;*/
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memcpy(&avx, &avy, sizeof(avx));
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if (fingerpath) execv(fingerpath, avx);
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execv(_PATH_FINGER, avx);
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execv(_ALT_PATH_FINGER_1, avx);
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execv(_ALT_PATH_FINGER_2, avx);
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execv(_ALT_PATH_FINGER_3, avx);
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syslog(LOG_ERR, "Finger program not found\n");
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exit(1);
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#if 0
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}
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/* parent */
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close(p[1]);
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/* convert \n to \r\n. This should be an option to finger... */
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fp = fdopen(p[0], "r");
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if (!fp) {
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fatal("fdopen", 1, 1, 0);
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}
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while ((ch = getc(fp)) != EOF) {
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if (ch == '\n') putchar('\r');
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putchar(ch);
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}
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return 0;
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#endif
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}
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