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Add dnsmasq module files
It implements an idea to save dhcp hosts' macaddr vs. ipaddr mappings to static file and make dnsmasq loading it with "--dhcp-hostsfile" option, originally suggested by Dan, and can address the problem that too many "--dhcp-host" args hitting ARG_MAX limit * src/util/dnsmasq.h src/util/dnsmasq.c: adds the 2 new files
This commit is contained in:
Satoru SATOH
Daniel Veillard
parent
4ce54ef5c7
commit
4ad65ab86a
341
src/util/dnsmasq.c
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341
src/util/dnsmasq.c
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@ -0,0 +1,341 @@
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/*
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* Copyright (C) 2007-2010 Red Hat, Inc.
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* Copyright (C) 2010 Satoru SATOH <satoru.satoh@gmail.com>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library 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 GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* Based on iptables.c
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*/
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#include <config.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdarg.h>
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#include <string.h>
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#include <errno.h>
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#include <limits.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <signal.h>
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#ifdef HAVE_PATHS_H
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# include <paths.h>
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#endif
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#include "internal.h"
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#include "datatypes.h"
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#include "dnsmasq.h"
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#include "util.h"
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#include "memory.h"
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#include "virterror_internal.h"
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#include "logging.h"
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#define VIR_FROM_THIS VIR_FROM_NETWORK
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#define DNSMASQ_HOSTSFILE_SUFFIX "hostsfile"
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static void
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dhcphostFree(dnsmasqDhcpHost *host)
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{
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VIR_FREE(host->host);
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}
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static void
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hostsfileFree(dnsmasqHostsfile *hostsfile)
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{
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unsigned int i;
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if (hostsfile->hosts) {
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for (i = 0; i < hostsfile->nhosts; i++)
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dhcphostFree(&hostsfile->hosts[i]);
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VIR_FREE(hostsfile->hosts);
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hostsfile->nhosts = 0;
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}
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VIR_FREE(hostsfile->path);
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VIR_FREE(hostsfile);
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}
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static int
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hostsfileAdd(dnsmasqHostsfile *hostsfile,
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const char *mac,
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const char *ip,
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const char *name)
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{
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if (VIR_REALLOC_N(hostsfile->hosts, hostsfile->nhosts + 1) < 0)
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goto alloc_error;
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if (name) {
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if (virAsprintf(&hostsfile->hosts[hostsfile->nhosts].host, "%s,%s,%s",
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mac, ip, name) < 0) {
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goto alloc_error;
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}
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} else {
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if (virAsprintf(&hostsfile->hosts[hostsfile->nhosts].host, "%s,%s",
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mac, ip) < 0) {
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goto alloc_error;
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}
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}
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hostsfile->nhosts++;
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return 0;
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alloc_error:
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virReportSystemError(ENOMEM,
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_("Failed to add dhcp host entry: mac=%s, ip=%s, name=%s\n"),
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mac, ip, (name ? name : "(null)"));
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return -1;
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}
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static dnsmasqHostsfile *
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hostsfileNew(const char *name,
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const char *config_dir)
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{
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int err;
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dnsmasqHostsfile *hostsfile;
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if (VIR_ALLOC(hostsfile) < 0)
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return NULL;
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hostsfile->hosts = NULL;
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hostsfile->nhosts = 0;
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if (virAsprintf(&hostsfile->path, "%s/%s.%s", config_dir, name,
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DNSMASQ_HOSTSFILE_SUFFIX) < 0) {
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goto error;
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}
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if ((err = virFileMakePath(config_dir))) {
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virReportSystemError(err, _("cannot create config directory '%s'"),
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config_dir);
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goto error;
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}
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return hostsfile;
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error:
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hostsfileFree(hostsfile);
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return NULL;
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}
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static int
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hostsfileWrite(const char *path,
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dnsmasqDhcpHost *hosts,
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unsigned int nhosts)
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{
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char *tmp;
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FILE *f;
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bool istmp = true;
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unsigned int i;
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int rc = 0;
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if (nhosts == 0)
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return rc;
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if (virAsprintf(&tmp, "%s.new", path) < 0)
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return ENOMEM;
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if (!(f = fopen(tmp, "w"))) {
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istmp = false;
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if (!(f = fopen(path, "w"))) {
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rc = errno;
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goto cleanup;
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}
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}
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for (i = 0; i < nhosts; i++) {
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if (fputs(hosts[i].host, f) == EOF || fputc('\n', f) == EOF) {
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rc = errno;
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fclose(f);
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if (istmp)
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unlink(tmp);
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goto cleanup;
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}
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}
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if (fclose(f) == EOF) {
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rc = errno;
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goto cleanup;
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}
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if (istmp) {
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if (rename(tmp, path) < 0) {
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rc = errno;
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unlink(tmp);
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goto cleanup;
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}
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if (unlink(tmp) < 0) {
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rc = errno;
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goto cleanup;
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}
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}
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cleanup:
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VIR_FREE(tmp);
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return rc;
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}
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static int
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hostsfileSave(dnsmasqHostsfile *hostsfile)
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{
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int err = hostsfileWrite(hostsfile->path, hostsfile->hosts,
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hostsfile->nhosts);
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if (err < 0) {
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virReportSystemError(err, _("cannot write config file '%s'"),
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hostsfile->path);
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return -1;
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}
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return 0;
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}
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static int
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hostsfileDelete(dnsmasqHostsfile *hostsfile)
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{
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if (!virFileExists(hostsfile->path))
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return 0;
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if (unlink(hostsfile->path) < 0) {
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virReportSystemError(errno, _("cannot remove config file '%s'"),
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hostsfile->path);
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return -1;
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}
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return 0;
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}
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/**
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* dnsmasqContextNew:
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*
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* Create a new Dnsmasq context
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*
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* Returns a pointer to the new structure or NULL in case of error
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*/
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dnsmasqContext *
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dnsmasqContextNew(const char *network_name,
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const char *config_dir)
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{
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dnsmasqContext *ctx;
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if (VIR_ALLOC(ctx) < 0)
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return NULL;
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if (!(ctx->hostsfile = hostsfileNew(network_name, config_dir)))
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goto error;
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return ctx;
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error:
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dnsmasqContextFree(ctx);
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return NULL;
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}
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/**
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* dnsmasqContextFree:
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* @ctx: pointer to the dnsmasq context
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*
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* Free the resources associated with an dnsmasq context
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*/
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void
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dnsmasqContextFree(dnsmasqContext *ctx)
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{
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if (!ctx)
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return;
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if (ctx->hostsfile)
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hostsfileFree(ctx->hostsfile);
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VIR_FREE(ctx);
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}
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/**
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* dnsmasqAddDhcpHost:
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* @ctx: pointer to the dnsmasq context for each network
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* @mac: pointer to the string contains mac address of the host
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* @ip: pointer to the string contains ip address of the host
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* @name: pointer to the string contains hostname of the host or NULL
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*
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* Add dhcp-host entry.
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*/
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void
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dnsmasqAddDhcpHost(dnsmasqContext *ctx,
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const char *mac,
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const char *ip,
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const char *name)
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{
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if (ctx->hostsfile)
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hostsfileAdd(ctx->hostsfile, mac, ip, name);
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}
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/**
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* dnsmasqSave:
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* @ctx: pointer to the dnsmasq context for each network
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*
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* Saves all the configurations associated with a context to disk.
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*/
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int
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dnsmasqSave(const dnsmasqContext *ctx)
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{
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if (ctx->hostsfile)
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return hostsfileSave(ctx->hostsfile);
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return 0;
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}
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/**
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* dnsmasqDelete:
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* @ctx: pointer to the dnsmasq context for each network
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*
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* Delete all the configuration files associated with a context.
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*/
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int
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dnsmasqDelete(const dnsmasqContext *ctx)
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{
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if (ctx->hostsfile)
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return hostsfileDelete(ctx->hostsfile);
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return 0;
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}
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/**
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* dnsmasqReload:
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* @pid: the pid of the target dnsmasq process
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*
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* Reloads all the configurations associated to a context
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*/
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int
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dnsmasqReload(pid_t pid)
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{
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if (kill(pid, SIGHUP) != 0) {
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virReportSystemError(errno,
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_("Failed to make dnsmasq (PID: %d) reload config files.\n"),
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pid);
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return -1;
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}
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return 0;
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}
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59
src/util/dnsmasq.h
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59
src/util/dnsmasq.h
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@ -0,0 +1,59 @@
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/*
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* Copyright (C) 2007-2010 Red Hat, Inc.
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* Copyright (C) 2010 Satoru SATOH <satoru.satoh@gmail.com>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library 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 GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* based on iptables.h
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*/
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#ifndef __DNSMASQ_H__
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# define __DNSMASQ_H__
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typedef struct
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{
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/*
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* Each entry holds a string, "<mac_addr>,<hostname>,<ip_addr>" such as
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* "01:23:45:67:89:0a,foo,10.0.0.3".
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*/
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char *host;
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} dnsmasqDhcpHost;
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typedef struct
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{
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unsigned int nhosts;
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dnsmasqDhcpHost *hosts;
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char *path; /* Absolute path of dnsmasq's hostsfile. */
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} dnsmasqHostsfile;
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typedef struct
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{
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dnsmasqHostsfile *hostsfile;
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} dnsmasqContext;
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dnsmasqContext * dnsmasqContextNew(const char *network_name,
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const char *config_dir);
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void dnsmasqContextFree(dnsmasqContext *ctx);
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void dnsmasqAddDhcpHost(dnsmasqContext *ctx,
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const char *mac,
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const char *ip,
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const char *name);
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int dnsmasqSave(const dnsmasqContext *ctx);
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int dnsmasqDelete(const dnsmasqContext *ctx);
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int dnsmasqReload(pid_t pid);
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#endif /* __DNSMASQ_H__ */
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