autofs-5.0.4 - uris list locking fix

From: Ian Kent <raven@themaw.net>

The ldap uris list doesn't need to change we just need to keep

track of current server uri in the list and try to connect in

a round robin order. Also it's possible multiple concurrent

connection attempts may not be able to use the full list of

servers (if one is present).

---

 CHANGELOG             |    1 +

 include/lookup_ldap.h |    3 +-

 modules/lookup_ldap.c |   68 ++++++++++++++++++++++---------------------------

 3 files changed, 33 insertions(+), 39 deletions(-)

diff --git a/CHANGELOG b/CHANGELOG

index 3199e4d..b093451 100644

--- a/CHANGELOG

+++ b/CHANGELOG

@@ -10,6 +10,7 @@

 - clear the quoted flag after each character from program map input.

 - use CLOEXEC flag for setmntent also.

 - fix hosts map use after free.

+- fix uri list locking (again).

 4/11/2008 autofs-5.0.4

 -----------------------

diff --git a/include/lookup_ldap.h b/include/lookup_ldap.h

index f9ed778..b47bf5d 100644

--- a/include/lookup_ldap.h

+++ b/include/lookup_ldap.h

@@ -55,7 +55,8 @@ struct lookup_context {

  	 * given in configuration.

  	 */

 	pthread_mutex_t uris_mutex;

-	struct list_head *uri;

+	struct list_head *uris;

+	struct ldap_uri *uri;

 	char *cur_host;

 	struct ldap_searchdn *sdns;

diff --git a/modules/lookup_ldap.c b/modules/lookup_ldap.c

index 6ba80eb..b6784e1 100644

--- a/modules/lookup_ldap.c

+++ b/modules/lookup_ldap.c

@@ -137,7 +137,7 @@ static void uris_mutex_unlock(struct lookup_context *ctxt)

 	return;

 }

-int bind_ldap_anonymous(unsigned logopt, LDAP *ldap, struct lookup_context *ctxt)

+int bind_ldap_anonymous(unsigned logopt, LDAP *ldap, const char *uri, struct lookup_context *ctxt)

 {

 	int rv;

@@ -147,16 +147,14 @@ int bind_ldap_anonymous(unsigned logopt, LDAP *ldap, struct lookup_context *ctxt

 		rv = ldap_simple_bind_s(ldap, NULL, NULL);

 	if (rv != LDAP_SUCCESS) {

-		if (!ctxt->uri) {

+		if (!ctxt->uris) {

 			crit(logopt, MODPREFIX

 			     "Unable to bind to the LDAP server: "

 			     "%s, error %s", ctxt->server ? "" : "(default)",

 			     ldap_err2string(rv));

 		} else {

-			struct ldap_uri *uri;

-			uri = list_entry(ctxt->uri->next, struct ldap_uri, list);

 			info(logopt, MODPREFIX "Unable to bind to the LDAP server: "

-			     "%s, error %s", uri->uri, ldap_err2string(rv));

+			     "%s, error %s", uri, ldap_err2string(rv));

 		}

 		return -1;

 	}

@@ -498,7 +496,7 @@ static int find_query_dn(unsigned logopt, LDAP *ldap, struct lookup_context *ctx

 	return 0;

 }

-static int do_bind(unsigned logopt, LDAP *ldap, struct lookup_context *ctxt)

+static int do_bind(unsigned logopt, LDAP *ldap, const char *uri, struct lookup_context *ctxt)

 {

 	char *host = NULL, *nhost;

 	int rv, need_base = 1;

@@ -511,11 +509,11 @@ static int do_bind(unsigned logopt, LDAP *ldap, struct lookup_context *ctxt)

 		rv = autofs_sasl_bind(logopt, ldap, ctxt);

 		debug(logopt, MODPREFIX "autofs_sasl_bind returned %d", rv);

 	} else {

-		rv = bind_ldap_anonymous(logopt, ldap, ctxt);

+		rv = bind_ldap_anonymous(logopt, ldap, uri, ctxt);

 		debug(logopt, MODPREFIX "ldap anonymous bind returned %d", rv);

 	}

 #else

-	rv = bind_ldap_anonymous(logopt, ldap, ctxt);

+	rv = bind_ldap_anonymous(logopt, ldap, uri, ctxt);

 	debug(logopt, MODPREFIX "ldap anonymous bind returned %d", rv);

 #endif

@@ -584,7 +582,7 @@ static LDAP *do_connect(unsigned logopt, const char *uri, struct lookup_context

 	if (!ldap)

 		return NULL;

-	if (!do_bind(logopt, ldap, ctxt)) {

+	if (!do_bind(logopt, ldap, uri, ctxt)) {

 		unbind_ldap_connection(logopt, ldap, ctxt);

 		return NULL;

 	}

@@ -612,7 +610,7 @@ static LDAP *connect_to_server(unsigned logopt, const char *uri, struct lookup_c

 			return NULL;

 		}

-		if (!do_bind(logopt, ldap, ctxt)) {

+		if (!do_bind(logopt, ldap, uri, ctxt)) {

 			unbind_ldap_connection(logopt, ldap, ctxt);

 			autofs_sasl_dispose(ctxt);

 			error(logopt, MODPREFIX "cannot bind to server");

@@ -638,36 +636,34 @@ static LDAP *find_server(unsigned logopt, struct lookup_context *ctxt)

 {

 	LDAP *ldap = NULL;

 	struct ldap_uri *this;

-	struct list_head *p;

-	LIST_HEAD(tmp);

+	struct list_head *p, *first;

 	/* Try each uri in list, add connect fails to tmp list */

 	uris_mutex_lock(ctxt);

-	p = ctxt->uri->next;

-	while(p != ctxt->uri) {

+	if (!ctxt->uri)

+		first = ctxt->uris;

+	else

+		first = &ctxt->uri->list;

+	uris_mutex_unlock(ctxt);

+	p = first->next;

+	while(p != first) {

+		/* Skip list head */

+		if (p == ctxt->uris) {

+			p = p->next;

+			continue;

+		}

 		this = list_entry(p, struct ldap_uri, list);

-		uris_mutex_unlock(ctxt);

 		debug(logopt, "trying server %s", this->uri);

 		ldap = connect_to_server(logopt, this->uri, ctxt);

 		if (ldap) {

 			info(logopt, "connected to uri %s", this->uri);

 			uris_mutex_lock(ctxt);

+			ctxt->uri = this;

+			uris_mutex_unlock(ctxt);

 			break;

 		}

-		uris_mutex_lock(ctxt);

 		p = p->next;

-		list_del_init(&this->list);

-		list_add_tail(&this->list, &tmp);

 	}

-	/*

-	 * Successfuly connected uri (head of list) and untried uris are

-	 * in ctxt->uri list. Make list of remainder and failed uris with

-	 * failed uris at end and assign back to ctxt-uri.

-	 */

-	list_splice(ctxt->uri, &tmp);

-	INIT_LIST_HEAD(ctxt->uri);

-	list_splice(&tmp, ctxt->uri);

-	uris_mutex_unlock(ctxt);

 	return ldap;

 }

@@ -677,23 +673,19 @@ static LDAP *do_reconnect(unsigned logopt, struct lookup_context *ctxt)

 	struct ldap_uri *this;

 	LDAP *ldap;

-	if (ctxt->server || !ctxt->uri) {

+	if (ctxt->server || !ctxt->uris) {

 		ldap = do_connect(logopt, ctxt->server, ctxt);

 		return ldap;

 	}

 	uris_mutex_lock(ctxt);

-	this = list_entry(ctxt->uri->next, struct ldap_uri, list);

+	this = ctxt->uri;

 	uris_mutex_unlock(ctxt);

 	ldap = do_connect(logopt, this->uri, ctxt);

 	if (ldap)

 		return ldap;

-	/* Failed to connect, put at end of list */

-	uris_mutex_lock(ctxt);

-	list_del_init(&this->list);

-	list_add_tail(&this->list, ctxt->uri);

-	uris_mutex_unlock(ctxt);

+	/* Failed to connect, try to find a new server */

 #ifdef WITH_SASL

 	autofs_sasl_dispose(ctxt);

@@ -1259,8 +1251,8 @@ static void free_context(struct lookup_context *ctxt)

 		free(ctxt->cur_host);

 	if (ctxt->base)

 		free(ctxt->base);

-	if (ctxt->uri)

-		defaults_free_uris(ctxt->uri);

+	if (ctxt->uris)

+		defaults_free_uris(ctxt->uris);

 	ret = pthread_mutex_destroy(&ctxt->uris_mutex);

 	if (ret)

 		fatal(ret);

@@ -1344,7 +1336,7 @@ int lookup_init(const char *mapfmt, int argc, const char *const *argv, void **co

 		if (uris) {

 			validate_uris(uris);

 			if (!list_empty(uris))

-				ctxt->uri = uris;

+				ctxt->uris = uris;

 			else {

 				error(LOGOPT_ANY,

 				      "no valid uris found in config list"

@@ -1375,7 +1367,7 @@ int lookup_init(const char *mapfmt, int argc, const char *const *argv, void **co

 	}

 #endif

-	if (ctxt->server || !ctxt->uri) {

+	if (ctxt->server || !ctxt->uris) {

 		ldap = connect_to_server(LOGOPT_NONE, ctxt->server, ctxt);

 		if (!ldap) {

 			free_context(ctxt);