When upgrading from netbsd-6 to netbsd-7, I experienced this problem:
dhcrelay would not work in the background. The -d flag got mandatory
to have it working.
Looking at the ktrace, we can see that a background dhcrelay gets
EBADF to all its kevent(2) calls. This is because it uses a file descriptor
obtained from a kevent(2) call before doing the fork(2). And as kqueue(2)
man page says "The queue is not inherited by a child created with fork(2)."
In dhcrelay sources, the kqueue(2) call is made trhough dhcp_context_create():
#0 0xbaf9a570 in kqueue () from /usr/lib/libc.so.12
#1 0xbb5021bf in setup_watcher (mctx=0xbae03240, manager=0xbae8e000)
at src/external/bsd/bind/dist/lib/isc/unix/socket.c:4385
#2 0xbb5026f9 in isc__socketmgr_create2 (mctx=0xbae03240,
managerp=0x80b3f34 <dhcp_gbl_ctx+20>, maxsocks=4096)
at src/external/bsd/bind/dist/lib/isc/unix/socket.c:4711
#3 0xbb502368 in isc__socketmgr_create (mctx=0xbae03240,
managerp=0x80b3f34 <dhcp_gbl_ctx+20>)
at src/external/bsd/bind/dist/lib/isc/unix/socket.c:4585
#4 0xbb5076c6 in isc_socketmgr_createinctx (mctx=0xbae03240, actx=0xbae8c000,
managerp=0x80b3f34 <dhcp_gbl_ctx+20>)
at src/external/bsd/bind/dist/lib/isc/unix/../socket_api.c:64
#5 0x0808c92d in dhcp_context_create (flags=3, local4=0x0, local6=0x0)
at src/external/bsd/dhcp/lib/omapip/../../dist/omapip/isclib.c:184
#6 0x0804b624 in main (argc=4, argv=0xbf7fe8a0)
at src/external/bsd/dhcp/bin/relay/../../dist/relay/dhcrelay.c:211
The fix is to re-order the dhcp_context_create() and its dependencies after
the fork(2), which is the way it works in dhclient(8) and dhcpd(8). If nobody
opposes I will commit the patch below and submit it upstream.
Anyone knows of an open GNATS PR for this bug?
Index: dist/relay/dhcrelay.c
===================================================================
RCS file: /cvsroot/src/external/bsd/dhcp/dist/relay/dhcrelay.c,v
retrieving revision 1.5
diff -U 4 -r1.5 dhcrelay.c
--- dist/relay/dhcrelay.c 12 Jul 2014 12:09:37 -0000 1.5
+++ dist/relay/dhcrelay.c 4 Jun 2017 07:22:43 -0000
@@ -206,15 +206,8 @@
#if !defined(DEBUG)
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)
log_fatal("Can't initialize OMAPI: %s",
@@ -535,19 +528,8 @@
"option definition.");
}
#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;
FILE *pf;
@@ -586,8 +568,26 @@
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;
#ifdef DHCPv6
--
Emmanuel Dreyfus
http://hcpnet.free.fr/pubz
m...@netbsd.org
