Parse 'timeout' and 'attempts' from resolv.conf

It was supported by lwres in BIND 9.11, and is still mentioned in
the manual page. Restore support for it by adding it to libirs.

bin/dig/dighost.c

@@ -114,7 +114,7 @@ isc_sockaddr_t localaddr;
 isc_refcount_t sendcount = ATOMIC_VAR_INIT(0);
 isc_refcount_t recvcount = ATOMIC_VAR_INIT(0);
 int ndots = -1;
-int tries = 3;
+int tries = -1;
 int lookup_counter = 0;
 
 static char servercookie[256];
@@ -1276,6 +1276,17 @@ setup_system(bool ipv4only, bool ipv6only) {
 		ndots = irs_resconf_getndots(resconf);
 		debug("ndots is %d.", ndots);
 	}
+	if (timeout == 0) {
+		timeout = irs_resconf_gettimeout(resconf);
+		debug("timeout is %d.", timeout);
+	}
+	if (tries == -1) {
+		tries = irs_resconf_getattempts(resconf);
+		if (tries == 0) {
+			tries = 3;
+		}
+		debug("retries is %d.", tries);
+	}
 
 	/* If user doesn't specify server use nameservers from resolv.conf. */
 	if (ISC_LIST_EMPTY(server_list)) {

lib/irs/include/irs/resconf.h

@@ -115,4 +115,24 @@ irs_resconf_getndots(irs_resconf_t *conf);
  *\li	'conf' is a valid resconf object.
  */
 
+unsigned int
+irs_resconf_getattempts(irs_resconf_t *conf);
+/*%<
+ * Return the 'attempts' value stored in 'conf'.
+ *
+ * Requires:
+ *
+ *\li	'conf' is a valid resconf object.
+ */
+
+unsigned int
+irs_resconf_gettimeout(irs_resconf_t *conf);
+/*%<
+ * Return the 'timeout' value stored in 'conf'.
+ *
+ * Requires:
+ *
+ *\li	'conf' is a valid resconf object.
+ */
+
 ISC_LANG_ENDDECLS

lib/irs/resconf.c

@@ -74,6 +74,13 @@
 #define RESCONFMAXLINELEN     256U /*%< max size of a line */
 #define RESCONFMAXSORTLIST    10U  /*%< max 10 */
 
+#define CHECK(op)                            \
+	do {                                 \
+		result = (op);               \
+		if (result != ISC_R_SUCCESS) \
+			goto cleanup;        \
+	} while (0)
+
 /*!
  * configuration data structure
  */
@@ -108,6 +115,10 @@ struct irs_resconf {
 	uint8_t resdebug;
 	/*%< set to n in 'options ndots:n' */
 	uint8_t ndots;
+	/*%< set to n in 'options attempts:n' */
+	uint8_t attempts;
+	/*%< set to n in 'options timeout:n' */
+	uint8_t timeout;
 };
 
 static isc_result_t
@@ -165,8 +176,8 @@ eatwhite(FILE *fp) {
  */
 static int
 getword(FILE *fp, char *buffer, size_t size) {
+	char *p = NULL;
 	int ch;
-	char *p;
 
 	REQUIRE(buffer != NULL);
 	REQUIRE(size > 0U);
@@ -446,11 +457,26 @@ resconf_parsesortlist(irs_resconf_t *conf, FILE *fp) {
 	return (ISC_R_SUCCESS);
 }
 
+static isc_result_t
+resconf_optionnumber(const char *word, uint8_t *number) {
+	char *p;
+	long n;
+
+	n = strtol(word, &p, 10);
+	if (*p != '\0') { /* Bad string. */
+		return (ISC_R_UNEXPECTEDTOKEN);
+	}
+	if (n < 0 || n > 0xff) { /* Out of range. */
+		return (ISC_R_RANGE);
+	}
+	*number = n;
+	return (ISC_R_SUCCESS);
+}
+
 static isc_result_t
 resconf_parseoption(irs_resconf_t *conf, FILE *fp) {
 	int delim;
-	long ndots;
+	isc_result_t result = ISC_R_SUCCESS;
-	char *p;
 	char word[RESCONFMAXLINELEN];
 
 	delim = getword(fp, word, sizeof(word));
@@ -462,14 +488,11 @@ resconf_parseoption(irs_resconf_t *conf, FILE *fp) {
 		if (strcmp("debug", word) == 0) {
 			conf->resdebug = 1;
 		} else if (strncmp("ndots:", word, 6) == 0) {
-			ndots = strtol(word + 6, &p, 10);
+			CHECK(resconf_optionnumber(word + 6, &conf->ndots));
-			if (*p != '\0') { /* Bad string. */
+		} else if (strncmp("attempts:", word, 9) == 0) {
-				return (ISC_R_UNEXPECTEDTOKEN);
+			CHECK(resconf_optionnumber(word + 9, &conf->attempts));
-			}
+		} else if (strncmp("timeout:", word, 8) == 0) {
-			if (ndots < 0 || ndots > 0xff) { /* Out of range. */
+			CHECK(resconf_optionnumber(word + 8, &conf->timeout));
-				return (ISC_R_RANGE);
-			}
-			conf->ndots = (uint8_t)ndots;
 		}
 
 		if (delim == EOF || delim == '\n') {
@@ -479,7 +502,8 @@ resconf_parseoption(irs_resconf_t *conf, FILE *fp) {
 		}
 	}
 
-	return (ISC_R_SUCCESS);
+cleanup:
+	return (result);
 }
 
 static isc_result_t
@@ -521,6 +545,8 @@ irs_resconf_load(isc_mem_t *mctx, const char *filename, irs_resconf_t **confp) {
 	conf->sortlistnxt = 0;
 	conf->resdebug = 0;
 	conf->ndots = 1;
+	conf->attempts = 3;
+	conf->timeout = 0;
 	for (i = 0; i < RESCONFMAXSEARCH; i++) {
 		conf->search[i] = NULL;
 	}
@@ -669,3 +695,17 @@ irs_resconf_getndots(irs_resconf_t *conf) {
 
 	return ((unsigned int)conf->ndots);
 }
+
+unsigned int
+irs_resconf_getattempts(irs_resconf_t *conf) {
+	REQUIRE(IRS_RESCONF_VALID(conf));
+
+	return ((unsigned int)conf->attempts);
+}
+
+unsigned int
+irs_resconf_gettimeout(irs_resconf_t *conf) {
+	REQUIRE(IRS_RESCONF_VALID(conf));
+
+	return ((unsigned int)conf->timeout);
+}