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Fix buggy dhcrelay(8) requirement to stay in foreground

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This version of dhcrelay(8) needed to stay inforeground with -d flag in
order to service requests. Running inbackground turned it deaf to DHCP
requests.

This was caused by wrong kqueue(2) usage, where kevent(2) was used with
a file descriptor obtained by a kqueue(2) call done before fork(2).
kqueue(2) man page says "The queue is not inherited by a child created
with fork(2)". As a result, kevent(2) calls always got EBADF.

The fix is to reorder function calls in dhcrelay(8) main() function.
dhcp_context_create(), which causes kqueue(2) to be invoked, is
moved with its dependencies after fork(2). This matches the code layout
of dhclient(8) and dhcpd(8), which do not have the bug.

The fix was not submitted upstream since latest ISC DHCP code was
refactored and does not have the bug anymore.
This commit is contained in:
manu 2017-06-05 07:35:23 +00:00
parent 58810bf006
commit dd84686325
1 changed files with 21 additions and 21 deletions
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42
external/bsd/dhcp/dist/relay/dhcrelay.c vendored
View File

@ -1,4 +1,4 @@
/* $NetBSD: dhcrelay.c,v 1.6 2016/01/10 20:10:45 christos Exp $ */
/* $NetBSD: dhcrelay.c,v 1.7 2017/06/05 07:35:23 manu Exp $ */
/* dhcrelay.c
DHCP/BOOTP Relay Agent. */
@ -28,7 +28,7 @@
*/
#include <sys/cdefs.h>
__RCSID("$NetBSD: dhcrelay.c,v 1.6 2016/01/10 20:10:45 christos Exp $");
__RCSID("$NetBSD: dhcrelay.c,v 1.7 2017/06/05 07:35:23 manu Exp $");
#include "dhcpd.h"
#include <syslog.h>
@ -207,13 +207,6 @@ main(int argc, char **argv) {
setlogmask(LOG_UPTO(LOG_INFO));
#endif
/* Set up the isc and dns library managers */
status = dhcp_context_create(DHCP_CONTEXT_PRE_DB | DHCP_CONTEXT_POST_DB,
NULL, NULL);
if (status != ISC_R_SUCCESS)
log_fatal("Can't initialize context: %s",
isc_result_totext(status));
/* Set up the OMAPI. */
status = omapi_init();
if (status != ISC_R_SUCCESS)
@ -536,17 +529,6 @@ main(int argc, char **argv) {
}
#endif
/* Get the current time... */
gettimeofday(&cur_tv, NULL);
/* Discover all the network interfaces. */
discover_interfaces(DISCOVER_RELAY);
#ifdef DHCPv6
if (local_family == AF_INET6)
setup_streams();
#endif
/* Become a daemon... */
if (!no_daemon) {
int pid;
@ -587,6 +569,24 @@ main(int argc, char **argv) {
IGNORE_RET (chdir("/"));
}
/* Set up the isc and dns library managers */
status = dhcp_context_create(DHCP_CONTEXT_PRE_DB | DHCP_CONTEXT_POST_DB,
NULL, NULL);
if (status != ISC_R_SUCCESS)
log_fatal("Can't initialize context: %s",
isc_result_totext(status));
/* Get the current time... */
gettimeofday(&cur_tv, NULL);
/* Discover all the network interfaces. */
discover_interfaces(DISCOVER_RELAY);
#ifdef DHCPv6
if (local_family == AF_INET6)
setup_streams();
#endif
/* Set up the packet handler... */
if (local_family == AF_INET)
bootp_packet_handler = do_relay4;
@ -948,7 +948,7 @@ find_interface_by_agent_option(struct dhcp_packet *packet,
*/
#include <sys/cdefs.h>
__RCSID("$NetBSD: dhcrelay.c,v 1.6 2016/01/10 20:10:45 christos Exp $");
__RCSID("$NetBSD: dhcrelay.c,v 1.7 2017/06/05 07:35:23 manu Exp $");
static int
add_relay_agent_options(struct interface_info *ip, struct dhcp_packet *packet,
unsigned length, struct in_addr giaddr) {