If getifaddrs blocks on a lock and a SIGALRM happens to fire while it

is block, it will return with EINTR. WE need to detect that and just

try again.

This is NTP bug 2565. Remove this patch when upgrading to a version that

has bug 2565 fixed in it.

--- lib/isc/unix/ifiter_getifaddrs.c

+++ lib/isc/unix/ifiter_getifaddrs.c

@@ -55,6 +55,8 @@ isc_interfaceiter_create(isc_mem_t *mctx

 	isc_interfaceiter_t *iter;

 	isc_result_t result;

 	char strbuf[ISC_STRERRORSIZE];

+	int trys;

+	int ret;

 	REQUIRE(mctx != NULL);

 	REQUIRE(iterp != NULL);

@@ -86,15 +88,21 @@ isc_interfaceiter_create(isc_mem_t *mctx

 	iter->valid = ISC_R_FAILURE;

 #endif

-	if (getifaddrs(&iter->ifaddrs) < 0) {

+	for (trys = 0; trys < 3; trys++) {

+		if ((ret = getifaddrs(&iter->ifaddrs)) >= 0)

+			break;

+		if (errno != EINTR) 

+			break;

+	}

+	if (ret < 0) {

 		isc__strerror(errno, strbuf, sizeof(strbuf));

 		UNEXPECTED_ERROR(__FILE__, __LINE__,

-				 isc_msgcat_get(isc_msgcat,

-						ISC_MSGSET_IFITERGETIFADDRS,

-						ISC_MSG_GETIFADDRS,

-						"getting interface "

-						"addresses: getifaddrs: %s"),

-				 strbuf);

+		    isc_msgcat_get(isc_msgcat,

+		    ISC_MSGSET_IFITERGETIFADDRS,

+		    ISC_MSG_GETIFADDRS,

+		    "getting interface "

+		    "addresses: getifaddrs: %s"),

+		    strbuf);

 		result = ISC_R_UNEXPECTED;

 		goto failure;

 	}