[MINOR] maintain a global session list in order to ease debugging

Now the global variable 'sessions' will be a dual-linked list of all
known sessions. The list element is set at the beginning of the session
so that it's easier to follow them all with gdb.

include/proto/session.h

@@ -27,6 +27,7 @@
 #include <types/session.h>
 
 extern struct pool_head *pool2_session;
+extern struct list sessions;
 
 void session_free(struct session *s);
 

include/types/session.h

@@ -152,6 +152,7 @@ enum {
  *    server should eventually be released.
  */
 struct session {
+	struct list list;			/* position in global sessions list */
 	struct task *task;			/* the task associated with this session */
 	/* application specific below */
 	struct proxy *fe;			/* the proxy this session depends on for the client side */

src/client.c

@@ -106,6 +106,8 @@ int event_accept(int fd) {
 			goto out_close;
 		}
 
+		LIST_ADDQ(&sessions, &s->list);
+
 		s->flags = 0;
 		s->term_trace = 0;
 
@@ -455,6 +457,7 @@ int event_accept(int fd) {
  out_free_task:
 	pool_free2(pool2_task, t);
  out_free_session:
+	LIST_DEL(&s->list);
 	pool_free2(pool2_session, s);
  out_close:
 	close(cfd);

src/proto_uxst.c

@@ -411,12 +411,15 @@ int uxst_event_accept(int fd) {
 			return 0;
 		}
 
+		LIST_ADDQ(&sessions, &s->list);
+
 		s->flags = 0;
 		s->term_trace = 0;
 
 		if ((t = pool_alloc2(pool2_task)) == NULL) {
 			Alert("out of memory in uxst_event_accept().\n");
 			close(cfd);
+			LIST_DEL(&s->list);
 			pool_free2(pool2_session, s);
 			return 0;
 		}
@@ -428,6 +431,7 @@ int uxst_event_accept(int fd) {
 			Alert("accept(): not enough free sockets. Raise -n argument. Giving up.\n");
 			close(cfd);
 			pool_free2(pool2_task, t);
+			LIST_DEL(&s->list);
 			pool_free2(pool2_session, s);
 			return 0;
 		}
@@ -436,6 +440,7 @@ int uxst_event_accept(int fd) {
 			Alert("accept(): cannot set the socket in non blocking mode. Giving up\n");
 			close(cfd);
 			pool_free2(pool2_task, t);
+			LIST_DEL(&s->list);
 			pool_free2(pool2_session, s);
 			return 0;
 		}
@@ -467,6 +472,7 @@ int uxst_event_accept(int fd) {
 		if ((s->req = pool_alloc2(pool2_buffer)) == NULL) { /* no memory */
 			close(cfd); /* nothing can be done for this fd without memory */
 			pool_free2(pool2_task, t);
+			LIST_DEL(&s->list);
 			pool_free2(pool2_session, s);
 			return 0;
 		}
@@ -475,6 +481,7 @@ int uxst_event_accept(int fd) {
 			pool_free2(pool2_buffer, s->req);
 			close(cfd); /* nothing can be done for this fd without memory */
 			pool_free2(pool2_task, t);
+			LIST_DEL(&s->list);
 			pool_free2(pool2_session, s);
 			return 0;
 		}

src/session.c

@@ -26,6 +26,7 @@
 
 
 struct pool_head *pool2_session;
+struct list sessions;
 
 /*
  * frees  the context associated to a session. It must have been removed first.
@@ -74,6 +75,7 @@ void session_free(struct session *s)
 	pool_free2(pool2_requri, txn->uri);
 	pool_free2(pool2_capture, txn->cli_cookie);
 	pool_free2(pool2_capture, txn->srv_cookie);
+	LIST_DEL(&s->list);
 	pool_free2(pool2_session, s);
 
 	/* We may want to free the maximum amount of pools if the proxy is stopping */
@@ -92,6 +94,7 @@ void session_free(struct session *s)
 /* perform minimal intializations, report 0 in case of error, 1 if OK. */
 int init_session()
 {
+	LIST_INIT(&sessions);
 	pool2_session = create_pool("session", sizeof(struct session), MEM_F_SHARED);
 	return pool2_session != NULL;
 }