[MAJOR] added a new state to listeners

There was a missing state for listeners, when they are not listening
but still attached to the protocol. The LI_ASSIGNED state was added
for this purpose. This permitted to clean up the assignment/release
workflow quite a bit. Generic enable/enable_all/disable/disable_all
primitives were added, and a disable_all entry was added to the
struct protocol.

include/proto/proto_uxst.h

@@ -28,6 +28,7 @@
 
 int uxst_event_accept(int fd);
 void uxst_add_listener(struct listener *listener);
+void uxst_del_listener(struct listener *listener);
 void process_uxst_stats(struct task *t, struct timeval *next);
 
 #endif /* _PROTO_PROTO_UXST_H */

include/proto/protocols.h

@@ -24,6 +24,33 @@
 
 #include <types/protocols.h>
 
+/* This function adds the specified listener's file descriptor to the polling
+ * lists if it is in the LI_LISTEN state. The listener enters LI_READY or
+ * LI_FULL state depending on its number of connections.
+ */
+void enable_listener(struct listener *listener);
+
+/* This function removes the specified listener's file descriptor from the
+ * polling lists if it is in the LI_READY or in the LI_FULL state. The listener
+ * enters LI_LISTEN.
+ */
+void disable_listener(struct listener *listener);
+
+/* This function adds all of the protocol's listener's file descriptors to the
+ * polling lists when they are in the LI_LISTEN state. It is intended to be
+ * used as a protocol's generic enable_all() primitive, for use after the
+ * fork(). It puts the listeners into LI_READY or LI_FULL states depending on
+ * their number of connections. It always returns ERR_NONE.
+ */
+int enable_all_listeners(struct protocol *proto);
+
+/* This function removes all of the protocol's listener's file descriptors from
+ * the polling lists when they are in the LI_READY or LI_FULL states. It is
+ * intended to be used as a protocol's generic disable_all() primitive. It puts
+ * the listeners into LI_LISTEN, and always returns ERR_NONE.
+ */
+int disable_all_listeners(struct protocol *proto);
+
 /* Registers the protocol <proto> */
 void protocol_register(struct protocol *proto);
 

include/types/protocols.h

@@ -35,10 +35,32 @@
 
 /* listener state */
 #define LI_NEW		0	/* not initialized yet */
-#define LI_INIT		1	/* attached to the protocol, but not listening yet */
+#define LI_INIT		1	/* all parameters filled in, but not assigned yet */
-#define LI_LISTEN	2	/* started, listening but not enabled */
+#define LI_ASSIGNED	2	/* assigned to the protocol, but not listening yet */
-#define LI_READY	3	/* started, listening and enabled */
+#define LI_LISTEN	3	/* started, listening but not enabled */
-#define LI_FULL		4	/* reached its connection limit */
+#define LI_READY	4	/* started, listening and enabled */
+#define LI_FULL		5	/* reached its connection limit */
+
+/* Listener transitions
+ * calloc()     set()      add_listener()       bind()
+ * -------> NEW ----> INIT ----------> ASSIGNED -----> LISTEN
+ * <-------     <----      <----------          <-----
+ *    free()   bzero()     del_listener()       unbind()
+ *
+ * The file descriptor is valid only during these three states :
+ *
+ *             disable()
+ * LISTEN <------------ READY
+ *   A|   ------------>  |A
+ *   ||  !max & enable() ||
+ *   ||                  ||
+ *   ||              max ||
+ *   || max & enable()   V| !max
+ *   |+---------------> FULL
+ *   +-----------------
+ *            disable()
+ *
+ */
 
 /* listener socket options */
 #define LI_O_NONE	0x0000
@@ -50,7 +72,7 @@
  */
 struct listener {
 	int fd;				/* the listen socket */
-	int state;			/* state: NEW, INIT, LISTEN, READY, FULL */
+	int state;			/* state: NEW, INIT, ASSIGNED, LISTEN, READY, FULL */
 	int options;			/* socket options : LI_O_* */
 	struct sockaddr_storage addr;	/* the address we listen to */
 	struct protocol *proto;		/* protocol this listener belongs to */
@@ -90,6 +112,7 @@ struct protocol {
 	int (*bind_all)(struct protocol *proto);	/* bind all unbound listeners */
 	int (*unbind_all)(struct protocol *proto);	/* unbind all bound listeners */
 	int (*enable_all)(struct protocol *proto);	/* enable all bound listeners */
+	int (*disable_all)(struct protocol *proto);	/* disable all bound listeners */
 	struct list listeners;				/* list of listeners using this protocol */
 	int nb_listeners;				/* number of listeners */
 	struct list list;				/* list of registered protocols */

src/proto_uxst.c

@@ -61,6 +61,34 @@
 #define MAXPATHLEN 128
 #endif
 
+static int uxst_bind_listeners(struct protocol *proto);
+static int uxst_unbind_listeners(struct protocol *proto);
+
+/* Note: must not be declared <const> as its list will be overwritten */
+static struct protocol proto_unix = {
+	.name = "unix_stream",
+	.sock_domain = PF_UNIX,
+	.sock_type = SOCK_STREAM,
+	.sock_prot = 0,
+	.sock_family = AF_UNIX,
+	.sock_addrlen = sizeof(struct sockaddr_un),
+	.l3_addrlen = sizeof(((struct sockaddr_un*)0)->sun_path),/* path len */
+	.read = &stream_sock_read,
+	.write = &stream_sock_write,
+	.bind_all = uxst_bind_listeners,
+	.unbind_all = uxst_unbind_listeners,
+	.enable_all = enable_all_listeners,
+	.disable_all = disable_all_listeners,
+	.listeners = LIST_HEAD_INIT(proto_unix.listeners),
+	.nb_listeners = 0,
+};
+
+
+/********************************
+ * 1) low-level socket functions
+ ********************************/
+
+
 /* This function creates a named PF_UNIX stream socket at address <path>. Note
  * that the path cannot be NULL nor empty. <uid> and <gid> different of -1 will
  * be used to change the socket owner. If <mode> is not 0, it will be used to
@@ -211,34 +239,30 @@ static void destroy_uxst_socket(const char *path)
 }
 
 
-/* This function creates all UNIX sockets bound to the protocol entry <proto>.
+/********************************
- * It is intended to be used as the protocol's bind_all() function.
+ * 2) listener-oriented functions
- * The sockets will be registered but not added to any fd_set, in order not to
+ ********************************/
- * loose them across the fork(). A call to uxst_enable_listeners() is needed
+
- * to complete initialization.
+
- *
+/* This function creates the UNIX socket associated to the listener. It changes
+ * the state from ASSIGNED to LISTEN. The socket is NOT enabled for polling.
  * The return value is composed from ERR_NONE, ERR_RETRYABLE and ERR_FATAL.
  */
-static int uxst_bind_listeners(struct protocol *proto)
+static int uxst_bind_listener(struct listener *listener)
 {
-	struct listener *listener;
-	int err = ERR_NONE;
 	int fd;
 		
-	list_for_each_entry(listener, &proto->listeners, proto_list) {
+	if (listener->state != LI_ASSIGNED)
-		if (listener->state != LI_INIT)
+		return ERR_NONE; /* already bound */
-			continue; /* already started */
 
 	fd = create_uxst_socket(((struct sockaddr_un *)&listener->addr)->sun_path,
 				listener->perm.ux.uid,
 				listener->perm.ux.gid,
 				listener->perm.ux.mode);
-		if (fd == -1) {
+	if (fd == -1)
-			err |= ERR_FATAL;
+		return ERR_FATAL;
-			continue;
-		}
 	
-		/* the socket is listening */
+	/* the socket is now listening */
 	listener->fd = fd;
 	listener->state = LI_LISTEN;
 
@@ -253,29 +277,81 @@ static int uxst_bind_listeners(struct protocol *proto)
 	fdtab[fd].peerlen = 0;
 	fdtab[fd].listener = NULL;
 	fdtab[fd].ev = 0;
-	}
+	return ERR_NONE;
-
-	return err;
 }
 
-/* This function adds the UNIX sockets file descriptors to the polling lists
+/* This function closes the UNIX sockets for the specified listener.
- * for all listeners in the LI_LISTEN state. It is intended to be used as the
+ * The listener enters the LI_ASSIGNED state. It always returns ERR_NONE.
- * protocol's enable_all() primitive, after the fork(). It always returns
- * ERR_NONE.
  */
-static int uxst_enable_listeners(struct protocol *proto)
+static int uxst_unbind_listener(struct listener *listener)
 {
-	struct listener *listener;
+	if (listener->state == LI_READY)
+		EV_FD_CLR(listener->fd, DIR_RD);
 
-	list_for_each_entry(listener, &proto->listeners, proto_list) {
+	if (listener->state >= LI_LISTEN) {
-		if (listener->state == LI_LISTEN) {
+		close(listener->fd);
-			EV_FD_SET(listener->fd, DIR_RD);
+		listener->state = LI_ASSIGNED;
-			listener->state = LI_READY;
+		destroy_uxst_socket(((struct sockaddr_un *)&listener->addr)->sun_path);
-		}
 	}
 	return ERR_NONE;
 }
 
+/* Add a listener to the list of unix stream listeners. The listener's state
+ * is automatically updated from LI_INIT to LI_ASSIGNED. The number of
+ * listeners is updated. This is the function to use to add a new listener.
+ */
+void uxst_add_listener(struct listener *listener)
+{
+	if (listener->state != LI_INIT)
+		return;
+	listener->state = LI_ASSIGNED;
+	listener->proto = &proto_unix;
+	LIST_ADDQ(&proto_unix.listeners, &listener->proto_list);
+	proto_unix.nb_listeners++;
+}
+
+/* Delete a listener from the list of unix stream listeners. The listener's
+ * state is automatically updated from LI_ASSIGNED to LI_INIT. The number of
+ * listeners is updated. Note that the listener must have previously been
+ * unbound. This is the function to use to remove a listener.
+ */
+void uxst_del_listener(struct listener *listener)
+{
+	if (listener->state != LI_ASSIGNED)
+		return;
+	listener->state = LI_INIT;
+	LIST_DEL(&listener->proto_list);
+	proto_unix.nb_listeners--;
+}
+
+
+/********************************
+ * 3) protocol-oriented functions
+ ********************************/
+
+
+/* This function creates all UNIX sockets bound to the protocol entry <proto>.
+ * It is intended to be used as the protocol's bind_all() function.
+ * The sockets will be registered but not added to any fd_set, in order not to
+ * loose them across the fork(). A call to uxst_enable_listeners() is needed
+ * to complete initialization.
+ *
+ * The return value is composed from ERR_NONE, ERR_RETRYABLE and ERR_FATAL.
+ */
+static int uxst_bind_listeners(struct protocol *proto)
+{
+	struct listener *listener;
+	int err = ERR_NONE;
+
+	list_for_each_entry(listener, &proto->listeners, proto_list) {
+		err |= uxst_bind_listener(listener);
+		if (err != ERR_NONE)
+			continue;
+	}
+	return err;
+}
+
+
 /* This function stops all listening UNIX sockets bound to the protocol
  * <proto>. It does not detaches them from the protocol.
  * It always returns ERR_NONE.
@@ -284,17 +360,17 @@ static int uxst_unbind_listeners(struct protocol *proto)
 {
 	struct listener *listener;
 
-	list_for_each_entry(listener, &proto->listeners, proto_list) {
+	list_for_each_entry(listener, &proto->listeners, proto_list)
-		if (listener->state != LI_INIT) {
+		uxst_unbind_listener(listener);
-			EV_FD_CLR(listener->fd, DIR_RD);
-			close(listener->fd);
-			listener->state = LI_INIT;
-			destroy_uxst_socket(((struct sockaddr_un *)&listener->addr)->sun_path);
-		}
-	}
 	return ERR_NONE;
 }
 
+
+/********************************
+ * 4) high-level functions
+ ********************************/
+
+
 /*
  * This function is called on a read event from a listen socket, corresponding
  * to an accept. It tries to accept as many connections as possible.
@@ -1400,32 +1476,6 @@ void process_uxst_stats(struct task *t, struct timeval *next)
 	tv_eternity(next);
 }
 
-/* Note: must not be declared <const> as its list will be overwritten */
-static struct protocol proto_unix = {
-	.name = "unix_stream",
-	.sock_domain = PF_UNIX,
-	.sock_type = SOCK_STREAM,
-	.sock_prot = 0,
-	.sock_family = AF_UNIX,
-	.sock_addrlen = sizeof(struct sockaddr_un),
-	.l3_addrlen = sizeof(((struct sockaddr_un*)0)->sun_path),/* path len */
-	.read = &stream_sock_read,
-	.write = &stream_sock_write,
-	.bind_all = uxst_bind_listeners,
-	.unbind_all = uxst_unbind_listeners,
-	.enable_all = uxst_enable_listeners,
-	.listeners = LIST_HEAD_INIT(proto_unix.listeners),
-	.nb_listeners = 0,
-};
-
-/* Adds listener to the list of unix stream listeners */
-void uxst_add_listener(struct listener *listener)
-{
-	listener->proto = &proto_unix;
-	LIST_ADDQ(&proto_unix.listeners, &listener->proto_list);
-	proto_unix.nb_listeners++;
-}
-
 __attribute__((constructor))
 static void __uxst_protocol_init(void)
 {

src/protocols.c

@@ -14,6 +14,7 @@
 #include <string.h>
 
 #include <common/config.h>
+#include <common/errors.h>
 #include <common/mini-clist.h>
 #include <common/standard.h>
 
@@ -22,6 +23,64 @@
 /* List head of all registered protocols */
 static struct list protocols = LIST_HEAD_INIT(protocols);
 
+/* This function adds the specified listener's file descriptor to the polling
+ * lists if it is in the LI_LISTEN state. The listener enters LI_READY or
+ * LI_FULL state depending on its number of connections.
+ */
+void enable_listener(struct listener *listener)
+{
+	if (listener->state == LI_LISTEN) {
+		if (listener->nbconn < listener->maxconn) {
+			EV_FD_SET(listener->fd, DIR_RD);
+			listener->state = LI_READY;
+		} else {
+			listener->state = LI_FULL;
+		}
+	}
+}
+
+/* This function removes the specified listener's file descriptor from the
+ * polling lists if it is in the LI_READY or in the LI_FULL state. The listener
+ * enters LI_LISTEN.
+ */
+void disable_listener(struct listener *listener)
+{
+	if (listener->state < LI_READY)
+		return;
+	if (listener->state == LI_READY)
+		EV_FD_CLR(listener->fd, DIR_RD);
+	listener->state = LI_LISTEN;
+}
+
+/* This function adds all of the protocol's listener's file descriptors to the
+ * polling lists when they are in the LI_LISTEN state. It is intended to be
+ * used as a protocol's generic enable_all() primitive, for use after the
+ * fork(). It puts the listeners into LI_READY or LI_FULL states depending on
+ * their number of connections. It always returns ERR_NONE.
+ */
+int enable_all_listeners(struct protocol *proto)
+{
+	struct listener *listener;
+
+	list_for_each_entry(listener, &proto->listeners, proto_list)
+		enable_listener(listener);
+	return ERR_NONE;
+}
+
+/* This function removes all of the protocol's listener's file descriptors from
+ * the polling lists when they are in the LI_READY or LI_FULL states. It is
+ * intended to be used as a protocol's generic disable_all() primitive. It puts
+ * the listeners into LI_LISTEN, and always returns ERR_NONE.
+ */
+int disable_all_listeners(struct protocol *proto)
+{
+	struct listener *listener;
+
+	list_for_each_entry(listener, &proto->listeners, proto_list)
+		disable_listener(listener);
+	return ERR_NONE;
+}
+
 /* Registers the protocol <proto> */
 void protocol_register(struct protocol *proto)
 {
@@ -37,7 +96,7 @@ void protocol_unregister(struct protocol *proto)
 	LIST_INIT(&proto->list);
 }
 
-/* binds all listeneres of all registered protocols. Returns a composition
+/* binds all listeners of all registered protocols. Returns a composition
  * of ERR_NONE, ERR_RETRYABLE, ERR_FATAL.
  */
 int protocol_bind_all(void)
@@ -88,3 +147,20 @@ int protocol_enable_all(void)
 	return err;
 }
 
+/* disables all listeners of all registered protocols. This may be used before
+ * a fork() to avoid duplicating poll lists. Returns a composition of ERR_NONE,
+ * ERR_RETRYABLE, ERR_FATAL.
+ */
+int protocol_disable_all(void)
+{
+	struct protocol *proto;
+	int err;
+
+	err = 0;
+	list_for_each_entry(proto, &protocols, list) {
+		if (proto->disable_all)
+			err |= proto->disable_all(proto);
+	}
+	return err;
+}
+