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/* $OpenBSD: ntp_dns.c,v 1.16 2015/12/19 17:55:29 reyk Exp $ */
/*
* Copyright (c) 2003-2008 Henning Brauer <henning@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
* IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
* OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/types.h>
#include <sys/resource.h>
#include <sys/time.h>
#include <err.h>
#include <errno.h>
#include <poll.h>
#include <fcntl.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include "ntpd.h"
volatile sig_atomic_t quit_dns = 0;
struct imsgbuf *ibuf_dns;
void sighdlr_dns(int);
int dns_dispatch_imsg(void);
void
sighdlr_dns(int sig)
{
switch (sig) {
case SIGTERM:
case SIGINT:
quit_dns = 1;
break;
}
}
pid_t
ntp_dns(int pipe_ntp[2], struct ntpd_conf *nconf, struct passwd *pw)
{
pid_t pid;
struct pollfd pfd[1];
int nfds, nullfd;
switch (pid = fork()) {
case -1:
fatal("cannot fork");
break;
case 0:
break;
default:
return (pid);
}
if (setpriority(PRIO_PROCESS, 0, 0) == -1)
log_warn("could not set priority");
/* in this case the parent didn't init logging and didn't daemonize */
if (nconf->settime && !nconf->debug) {
log_init(nconf->debug, LOG_DAEMON);
if (setsid() == -1)
fatal("setsid");
}
log_procinit("dns");
if ((nullfd = open("/dev/null", O_RDWR, 0)) == -1)
fatal(NULL);
if (!nconf->debug) {
dup2(nullfd, STDIN_FILENO);
dup2(nullfd, STDOUT_FILENO);
dup2(nullfd, STDERR_FILENO);
}
close(nullfd);
setproctitle("dns engine");
close(pipe_ntp[0]);
if (setgroups(1, &pw->pw_gid) ||
setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) ||
setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid))
fatal("can't drop privileges");
signal(SIGTERM, sighdlr_dns);
signal(SIGINT, sighdlr_dns);
signal(SIGHUP, SIG_IGN);
if ((ibuf_dns = malloc(sizeof(struct imsgbuf))) == NULL)
fatal(NULL);
imsg_init(ibuf_dns, pipe_ntp[1]);
if (pledge("stdio dns", NULL) == -1)
err(1, "pledge");
while (quit_dns == 0) {
pfd[0].fd = ibuf_dns->fd;
pfd[0].events = POLLIN;
if (ibuf_dns->w.queued)
pfd[0].events |= POLLOUT;
if ((nfds = poll(pfd, 1, INFTIM)) == -1)
if (errno != EINTR) {
log_warn("poll error");
quit_dns = 1;
}
if (nfds > 0 && (pfd[0].revents & POLLOUT))
if (msgbuf_write(&ibuf_dns->w) <= 0 &&
errno != EAGAIN) {
log_warn("pipe write error (to ntp engine)");
quit_dns = 1;
}
if (nfds > 0 && pfd[0].revents & POLLIN) {
nfds--;
if (dns_dispatch_imsg() == -1)
quit_dns = 1;
}
}
msgbuf_clear(&ibuf_dns->w);
free(ibuf_dns);
_exit(0);
}
int
dns_dispatch_imsg(void)
{
struct imsg imsg;
int n, cnt;
char *name;
struct ntp_addr *h, *hn;
struct ibuf *buf;
const char *str;
if ((n = imsg_read(ibuf_dns)) == -1 && errno != EAGAIN)
return (-1);
if (n == 0) { /* connection closed */
log_warnx("dispatch_imsg in main: pipe closed");
return (-1);
}
for (;;) {
if ((n = imsg_get(ibuf_dns, &imsg)) == -1)
return (-1);
if (n == 0)
break;
switch (imsg.hdr.type) {
case IMSG_HOST_DNS:
case IMSG_CONSTRAINT_DNS:
if (imsg.hdr.type == IMSG_HOST_DNS)
str = "IMSG_HOST_DNS";
else
str = "IMSG_CONSTRAINT_DNS";
name = imsg.data;
if (imsg.hdr.len < 1 + IMSG_HEADER_SIZE)
fatalx("invalid %s received", str);
imsg.hdr.len -= 1 + IMSG_HEADER_SIZE;
if (name[imsg.hdr.len] != '\0' ||
strlen(name) != imsg.hdr.len)
fatalx("invalid %s received", str);
if ((cnt = host_dns(name, &hn)) == -1)
break;
buf = imsg_create(ibuf_dns, imsg.hdr.type,
imsg.hdr.peerid, 0,
cnt * sizeof(struct sockaddr_storage));
if (cnt > 0) {
if (buf) {
for (h = hn; h != NULL; h = h->next)
if (imsg_add(buf, &h->ss,
sizeof(h->ss)) == -1) {
buf = NULL;
break;
}
}
host_dns_free(hn);
hn = NULL;
}
if (buf)
imsg_close(ibuf_dns, buf);
break;
default:
break;
}
imsg_free(&imsg);
}
return (0);
}
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