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/*
* Management of the rdnssd instance that we use to get DNS info out of
* RAs.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "netcfg.h"
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>
#include <signal.h>
#include <debian-installer.h>
static pid_t rdnssd_pid;
/* Spawn an rdnssd child process.
*
* Returns 1 on a successful start, and 0 on error. Stores the child pid in
* a module-internal global variable, as this is easier than trying to pass
* it around everywhere (given that we'll need to get at it in a signal
* handler...)
*/
int start_rdnssd(struct debconfclient *client)
{
if ((rdnssd_pid = fork()) == 0) { /* Child */
/* Dissociate from debconf */
fclose(client->out);
/* Kick things off */
execlp("rdnssd", "rdnssd", "-f", "-u", "root", "-r", "/tmp/rdnssd_resolv", NULL);
/* If we get here, something went wrong */
di_error("Could not exec dnssd: %s", strerror(errno));
exit(1);
} else if (rdnssd_pid == -1) {
di_warning("rdnssd fork failed: %s", strerror(errno));
return 0;
} else {
di_debug("rdnssd started; PID: %i", rdnssd_pid);
return 1;
}
}
/* Cleanup after the rdnssd process if/when it exits
*
* This gets called from the SIGCHLD handler to see if it was rdnssd that
* exited, and if so, perform whatever cleanup tasks were necessary.
*/
void cleanup_rdnssd()
{
int exit_status;
if (rdnssd_pid == -1)
/* Definitely wasn't us */
return;
if (waitpid(rdnssd_pid, &exit_status, WNOHANG) != rdnssd_pid)
/* Not us either */
return;
if (WIFEXITED(exit_status))
/* Yep, that was me */
rdnssd_pid = -1;
}
/* Read the nameserver entries that rdnssd may have written out into the
* interface struct.
*/
void read_rdnssd_nameservers(struct netcfg_interface *interface)
{
read_resolv_conf_nameservers("/tmp/rdnssd_resolv", interface);
}
/* Stop the rdnssd client process.
*/
void stop_rdnssd()
{
if (rdnssd_pid == -1) {
/* We're not running... that would be bad */
return;
}
di_debug("Stopping rdnssd, PID %i", rdnssd_pid);
kill(rdnssd_pid, SIGTERM);
}
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