s3: Add wbinfo --dc-info

wbinfo --dc-info prints the current DC name and IP address. This helps
diagnosing problems that might happen when a later wbinfo --ping-dc fails.

This patch started out by using the SAF and NBT cache entires, but those are
relatively short-lived. So I decided to invent a new gencache entry with a very
long timeout. We need to go via the gencache because when for some reason a
winbind child process is stuck, we can't query it for the current DC it's
connected to. This must eventually go away again when we have a fully async
winbind.

Autobuild-User: Volker Lendecke <vlendec@samba.org>
Autobuild-Date: Wed Jan 19 08:40:28 CET 2011 on sn-devel-104

4 files changed, 136 insertions, 2 deletions

diff --git a/nsswitch/libwbclient/wbc_util.c b/nsswitch/libwbclient/wbc_util.c
index e2e657a903..d2783f30d2 100644
--- a/nsswitch/libwbclient/wbc_util.c
+++ b/nsswitch/libwbclient/wbc_util.c
@@ -203,6 +203,92 @@ wbcErr wbcDomainInfo(const char *domain, struct wbcDomainInfo **dinfo)
 	return wbc_status;
 }
 
+/* Get the list of current DCs */
+wbcErr wbcDcInfo(const char *domain, size_t *num_dcs,
+		 const char ***dc_names, const char ***dc_ips)
+{
+	struct winbindd_request request;
+	struct winbindd_response response;
+	const char **names = NULL;
+	const char **ips = NULL;
+	wbcErr wbc_status = WBC_ERR_UNKNOWN_FAILURE;
+	size_t extra_len;
+	int i;
+	char *p;
+
+	/* Initialise request */
+
+	ZERO_STRUCT(request);
+	ZERO_STRUCT(response);
+
+	if (domain != NULL) {
+		strncpy(request.domain_name, domain,
+			sizeof(request.domain_name) - 1);
+	}
+
+	wbc_status = wbcRequestResponse(WINBINDD_DC_INFO,
+					&request, &response);
+	BAIL_ON_WBC_ERROR(wbc_status);
+
+	names = wbcAllocateStringArray(response.data.num_entries);
+	BAIL_ON_PTR_ERROR(names, wbc_status);
+
+	ips = wbcAllocateStringArray(response.data.num_entries);
+	BAIL_ON_PTR_ERROR(names, wbc_status);
+
+	wbc_status = WBC_ERR_INVALID_RESPONSE;
+
+	p = (char *)response.extra_data.data;
+
+	if (response.length < (sizeof(struct winbindd_response)+1)) {
+		goto done;
+	}
+
+	extra_len = response.length - sizeof(struct winbindd_response);
+
+	if (p[extra_len-1] != '\0') {
+		goto done;
+	}
+
+	for (i=0; i<response.data.num_entries; i++) {
+		char *q;
+
+		q = strchr(p, '\n');
+		if (q == NULL) {
+			goto done;
+		}
+		names[i] = strndup(p, q-p);
+		BAIL_ON_PTR_ERROR(names[i], wbc_status);
+		p = q+1;
+
+		q = strchr(p, '\n');
+		if (q == NULL) {
+			goto done;
+		}
+		ips[i] = strndup(p, q-p);
+		BAIL_ON_PTR_ERROR(ips[i], wbc_status);
+		p = q+1;
+	}
+	if (p[0] != '\0') {
+		goto done;
+	}
+
+        wbc_status = WBC_ERR_SUCCESS;
+done:
+	if (response.extra_data.data)
+		free(response.extra_data.data);
+
+	if (WBC_ERROR_IS_OK(wbc_status)) {
+		*num_dcs = response.data.num_entries;
+		*dc_names = names;
+		names = NULL;
+		*dc_ips = ips;
+		ips = NULL;
+	}
+	wbcFreeMemory(names);
+	wbcFreeMemory(ips);
+	return wbc_status;
+}
 
 /* Resolve a NetbiosName via WINS */
 wbcErr wbcResolveWinsByName(const char *name, char **ip)
diff --git a/nsswitch/libwbclient/wbclient.h b/nsswitch/libwbclient/wbclient.h
index e2f989094a..39670ab6ed 100644
--- a/nsswitch/libwbclient/wbclient.h
+++ b/nsswitch/libwbclient/wbclient.h
@@ -192,7 +192,6 @@ struct wbcDomainInfo {
 #define WBC_DOMINFO_TRUSTTYPE_IN_FOREST  0x00000002
 #define WBC_DOMINFO_TRUSTTYPE_EXTERNAL   0x00000003
 
-
 /**
  * @brief Auth User Parameters
  **/
@@ -992,6 +991,20 @@ wbcErr wbcDomainInfo(const char *domain,
 		     struct wbcDomainInfo **dinfo);
 
 /**
+ * @brief Lookup the currently contacted DCs
+ *
+ * @param domain        The domain to query
+ *
+ * @param num_dcs       Number of DCs currently known
+ * @param dc_names      Names of the currently known DCs
+ * @param dc_ips        IP addresses of the currently known DCs
+ *
+ * @return #wbcErr
+ **/
+wbcErr wbcDcInfo(const char *domain, size_t *num_dcs,
+		 const char ***dc_names, const char ***dc_ips);
+
+/**
  * @brief Enumerate the domain trusts known by Winbind
  *
  * @param **domains     Pointer to the allocated domain list array
diff --git a/nsswitch/wbinfo.c b/nsswitch/wbinfo.c
index 6ff66f8f3c..caa37f3c9e 100644
--- a/nsswitch/wbinfo.c
+++ b/nsswitch/wbinfo.c
@@ -787,6 +787,31 @@ static bool wbinfo_check_secret(const char *domain)
 	return true;
 }
 
+/* Find the currently connected DCs */
+
+static bool wbinfo_dc_info(const char *domain_name)
+{
+	wbcErr wbc_status = WBC_ERR_UNKNOWN_FAILURE;
+	size_t i, num_dcs;
+	const char **dc_names, **dc_ips;
+
+	wbc_status = wbcDcInfo(domain_name, &num_dcs,
+			       &dc_names, &dc_ips);
+	if (!WBC_ERROR_IS_OK(wbc_status)) {
+		printf("Could not find dc info %s\n",
+		       domain_name ? domain_name : "our domain");
+		return false;
+	}
+
+	for (i=0; i<num_dcs; i++) {
+		printf("%s (%s)\n", dc_names[i], dc_ips[i]);
+	}
+	wbcFreeMemory(dc_names);
+	wbcFreeMemory(dc_ips);
+
+	return true;
+}
+
 /* Change trust account password */
 
 static bool wbinfo_change_secret(const char *domain)
@@ -1921,6 +1946,7 @@ enum {
 	OPT_SEQUENCE,
 	OPT_GETDCNAME,
 	OPT_DSGETDCNAME,
+	OPT_DC_INFO,
 	OPT_USERDOMGROUPS,
 	OPT_SIDALIASES,
 	OPT_USERSIDS,
@@ -2030,6 +2056,8 @@ int main(int argc, char **argv, char **envp)
 		{ "getdcname", 0, POPT_ARG_STRING, &string_arg, OPT_GETDCNAME,
 		  "Get a DC name for a foreign domain", "domainname" },
 		{ "dsgetdcname", 0, POPT_ARG_STRING, &string_arg, OPT_DSGETDCNAME, "Find a DC for a domain", "domainname" },
+		{ "dc-info", 0, POPT_ARG_STRING, &string_arg, OPT_DC_INFO,
+		  "Find the currently known DCs", "domainname" },
 		{ "get-auth-user", 0, POPT_ARG_NONE, NULL, OPT_GET_AUTH_USER, "Retrieve user and password used by winbindd (root only)", NULL },
 		{ "ping", 'p', POPT_ARG_NONE, 0, 'p', "Ping winbindd to see if it is alive" },
 		{ "domain", 0, POPT_ARG_STRING, &opt_domain_name, OPT_DOMAIN_NAME, "Define to the domain to restrict operation", "domain" },
@@ -2443,6 +2471,11 @@ int main(int argc, char **argv, char **envp)
 				goto done;
 			}
 			break;
+		case OPT_DC_INFO:
+			if (!wbinfo_dc_info(string_arg)) {
+				goto done;
+			}
+			break;
 		case OPT_SEPARATOR: {
 			const char sep = winbind_separator();
 			if ( !sep ) {
diff --git a/nsswitch/winbind_struct_protocol.h b/nsswitch/winbind_struct_protocol.h
index 537754f688..9304702fa0 100644
--- a/nsswitch/winbind_struct_protocol.h
+++ b/nsswitch/winbind_struct_protocol.h
@@ -54,8 +54,9 @@ typedef char fstring[FSTRING_LEN];
  * 25: removed WINBINDD_SET_HWM
  *     removed WINBINDD_SET_MAPPING
  *     removed WINBINDD_REMOVE_MAPPING
+ * 26: added WINBINDD_DC_INFO
  */
-#define WINBIND_INTERFACE_VERSION 25
+#define WINBIND_INTERFACE_VERSION 26
 
 /* Have to deal with time_t being 4 or 8 bytes due to structure alignment.
    On a 64bit Linux box, we have to support a constant structure size
@@ -132,6 +133,7 @@ enum winbindd_cmd {
 				   struct winbindd_domain */
 	WINBINDD_GETDCNAME,	/* Issue a GetDCName Request */
 	WINBINDD_DSGETDCNAME,	/* Issue a DsGetDCName Request */
+	WINBINDD_DC_INFO,	/* Which DC are we connected to? */
 
 	WINBINDD_SHOW_SEQUENCE, /* display sequence numbers of domains */