d9571c62cf
Allow the user to specify the vendor identification option value using the -V switch. The default value is still "ndhc".
312 lines
9.1 KiB
C
312 lines
9.1 KiB
C
/* ndhc.c - DHCP client
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* Time-stamp: <2011-06-11 11:13:32 njk>
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*
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* (c) 2004-2011 Nicholas J. Kain <njkain at gmail dot com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <stdio.h>
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#include <sys/time.h>
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#include <sys/types.h>
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#include <sys/file.h>
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#include <unistd.h>
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#include <getopt.h>
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#include <stdlib.h>
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#include <signal.h>
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#include <time.h>
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#include <string.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <sys/epoll.h>
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#include <sys/signalfd.h>
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#include <net/if.h>
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#include <errno.h>
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#include <pwd.h>
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#include <grp.h>
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#include "ndhc-defines.h"
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#include "config.h"
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#include "state.h"
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#include "options.h"
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#include "packet.h"
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#include "sys.h"
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#include "ifchange.h"
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#include "arp.h"
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#include "netlink.h"
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#include "leasefile.h"
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#include "log.h"
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#include "chroot.h"
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#include "cap.h"
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#include "strl.h"
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#include "pidfile.h"
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#include "io.h"
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#define VERSION "1.0"
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struct client_state_t cs = {
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.init = 1,
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.epollFd = -1,
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.signalFd = -1,
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.listenFd = -1,
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.arpFd = -1,
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.nlFd = -1,
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.routerArp = "\0\0\0\0\0\0",
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};
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struct client_config_t client_config = {
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/* Default options. */
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.interface = "eth0",
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.arp = "\0\0\0\0\0\0",
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};
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static void show_usage(void)
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{
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printf(
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"Usage: ndhc [OPTIONS]\n\n"
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" -c, --clientid=CLIENTID Client identifier\n"
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" -H, --hostname=HOSTNAME Client hostname\n"
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" -h Alias for -H\n"
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" -f, --foreground Do not fork after getting lease\n"
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" -b, --background Fork to background if lease cannot be\n"
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" immediately negotiated.\n"
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" -p, --pidfile File to which the pid will be written\n"
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" -i, --interface=INTERFACE Interface to use (default: eth0)\n"
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" -n, --now Exit with failure if lease cannot be\n"
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" immediately negotiated.\n"
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" -q, --quit Quit after obtaining lease\n"
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" -r, --request=IP IP address to request (default: none)\n"
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" -u, --user Change privileges to this user\n"
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" -C, --chroot Directory to which udhcp should chroot\n"
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" -v, --version Display version\n"
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);
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exit(EXIT_SUCCESS);
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}
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static void signal_dispatch()
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{
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int t, off = 0;
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struct signalfd_siginfo si;
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again:
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t = read(cs.signalFd, (char *)&si + off, sizeof si - off);
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if (t < sizeof si - off) {
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if (t < 0) {
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if (t == EAGAIN || t == EWOULDBLOCK || t == EINTR)
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goto again;
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else
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suicide("signalfd read error");
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}
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off += t;
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}
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switch (si.ssi_signo) {
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case SIGUSR1:
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force_renew_action(&cs);
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break;
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case SIGUSR2:
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force_release_action(&cs);
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break;
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case SIGTERM:
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log_line("Received SIGTERM. Exiting gracefully.");
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exit(EXIT_SUCCESS);
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default:
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break;
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}
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}
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static void do_work(void)
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{
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struct epoll_event events[3];
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long long last_awake;
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int timeout_delta;
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cs.epollFd = epoll_create1(0);
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if (cs.epollFd == -1)
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suicide("epoll_create1 failed");
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setup_signals(&cs);
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epoll_add(&cs, cs.nlFd);
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set_listen_raw(&cs);
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timeout_action(&cs);
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for (;;) {
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last_awake = curms();
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int r = epoll_wait(cs.epollFd, events, 3, cs.timeout);
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if (r == -1) {
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if (errno == EINTR)
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continue;
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else
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suicide("epoll_wait failed");
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}
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for (int i = 0; i < r; ++i) {
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int fd = events[i].data.fd;
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if (fd == cs.signalFd)
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signal_dispatch();
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else if (fd == cs.listenFd)
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handle_packet(&cs);
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else if (fd == cs.arpFd)
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handle_arp_response(&cs);
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else if (fd == cs.nlFd)
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handle_nl_message(&cs);
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else
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suicide("epoll_wait: unknown fd");
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}
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timeout_delta = curms() - last_awake;
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cs.timeout -= timeout_delta;
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if (cs.timeout <= 0) {
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cs.timeout = 0;
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timeout_action(&cs);
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}
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}
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}
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int main(int argc, char **argv)
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{
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char chroot_dir[MAX_PATH_LENGTH] = "";
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int c;
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struct passwd *pwd;
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uid_t uid = 0;
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gid_t gid = 0;
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static struct option arg_options[] = {
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{"clientid", required_argument, 0, 'c'},
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{"foreground", no_argument, 0, 'f'},
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{"background", no_argument, 0, 'b'},
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{"pidfile", required_argument, 0, 'p'},
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{"leasefile", required_argument, 0, 'l'},
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{"hostname", required_argument, 0, 'H'},
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{"hostname", required_argument, 0, 'h'},
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{"interface", required_argument, 0, 'i'},
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{"now", no_argument, 0, 'n'},
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{"quit", no_argument, 0, 'q'},
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{"request", required_argument, 0, 'r'},
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{"version", no_argument, 0, 'v'},
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{"vendorid", required_argument, 0, 'V'},
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{"user", required_argument, 0, 'u'},
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{"chroot", required_argument, 0, 'C'},
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{"help", no_argument, 0, '?'},
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{0, 0, 0, 0}
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};
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/* get options */
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while (1) {
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int option_index = 0;
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c = getopt_long(argc, argv, "c:fbp:H:h:i:np:l:qr:u:C:vV:", arg_options,
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&option_index);
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if (c == -1) break;
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switch (c) {
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case 'c':
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strlcpy(client_config.clientid, optarg,
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sizeof client_config.clientid);
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break;
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case 'f':
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client_config.foreground = 1;
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gflags_detach = 0;
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break;
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case 'b':
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client_config.background_if_no_lease = 1;
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gflags_detach = 1;
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break;
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case 'p':
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strlcpy(pidfile, optarg, sizeof pidfile);
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break;
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case 'l':
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set_leasefile(optarg);
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break;
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case 'h':
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case 'H':
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strlcpy(client_config.hostname, optarg,
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sizeof client_config.hostname);
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break;
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case 'i':
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client_config.interface = optarg;
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break;
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case 'n':
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client_config.abort_if_no_lease = 1;
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break;
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case 'q':
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client_config.quit_after_lease = 1;
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break;
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case 'r':
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cs.clientAddr = inet_addr(optarg);
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break;
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case 'u':
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pwd = getpwnam(optarg);
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if (pwd) {
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uid = (int)pwd->pw_uid;
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gid = (int)pwd->pw_gid;
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} else {
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printf("Bad username provided.\n");
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exit(EXIT_FAILURE);
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}
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break;
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case 'C':
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strlcpy(chroot_dir, optarg, sizeof chroot_dir);
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break;
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case 'v':
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printf("ndhc, version " VERSION "\n\n");
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exit(EXIT_SUCCESS);
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break;
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case 'V':
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strlcpy(client_config.vendor, optarg,
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sizeof client_config.vendor);
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break;
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default:
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show_usage();
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}
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}
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log_line("ndhc client " VERSION " started.");
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if (client_config.foreground && !client_config.background_if_no_lease) {
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if (file_exists(pidfile, "w") == -1) {
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log_line("FATAL - cannot open pidfile for write!");
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exit(EXIT_FAILURE);
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}
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write_pid(pidfile);
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}
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if (nl_open(&cs) < 0) {
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log_line("FATAL - failed to open netlink socket");
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exit(EXIT_FAILURE);
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}
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if (nl_getifdata(client_config.interface, &cs) < 0) {
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log_line("FATAL - failed to get interface MAC and index");
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exit(EXIT_FAILURE);
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}
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open_leasefile();
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if (chdir(chroot_dir)) {
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printf("Failed to chdir(%s)!\n", chroot_dir);
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exit(EXIT_FAILURE);
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}
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if (chroot(chroot_dir)) {
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printf("Failed to chroot(%s)!\n", chroot_dir);
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exit(EXIT_FAILURE);
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}
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set_cap(uid, gid,
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"cap_net_bind_service,cap_net_broadcast,cap_net_raw=ep");
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drop_root(uid, gid);
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ifchange(NULL, IFCHANGE_DECONFIG);
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do_work();
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return EXIT_SUCCESS; // Never reached.
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}
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