1008: Call and reset conn->done when freeing conn->info.

In the places that set conn->info without freeing the original value,
assert that both conn->info and conn->done are NULL.

src/network/connection.c

@@ -452,6 +452,15 @@ free_connection_data(struct connection *conn)
 	shutdown_connection_stream(conn);
 
 	mem_free_set(&conn->info, NULL);
+	/* If conn->done is not NULL, it probably points to a function
+	 * that expects conn->info to be a specific kind of structure.
+	 * Such a function should not be called if a different pointer
+	 * is later assigned to conn->info.  Actually though, each
+	 * free_connection_data() call seems to be soon followed by
+	 * done_connection() so that conn->done would not be called
+	 * again in any case.  However, this assignment costs little
+	 * and may make things a bit safer.  */
+	conn->done = NULL;
 
 	kill_timer(&conn->timer);
 

src/protocol/bittorrent/connection.c

@@ -250,6 +250,7 @@ done_bittorrent_connection(struct connection *conn)
 	struct bittorrent_peer_connection *peer, *next;
 
 	assert(bittorrent);
+	assert(conn->done == done_bittorrent_connection);
 
 	/* We don't want the tracker to see the fetch. */
 	if (bittorrent->fetch)
@@ -270,6 +271,7 @@ done_bittorrent_connection(struct connection *conn)
 	free_list(bittorrent->peer_pool);
 
 	mem_free_set(&conn->info, NULL);
+	conn->done = NULL;
 }
 
 static struct bittorrent_connection *
@@ -277,12 +279,17 @@ init_bittorrent_connection(struct connection *conn)
 {
 	struct bittorrent_connection *bittorrent;
 
+	assert(conn->info == NULL);
+	assert(conn->done == NULL);
+	if_assert_failed return NULL;
+
 	bittorrent = mem_calloc(1, sizeof(*bittorrent));
 	if (!bittorrent) return NULL;
 
 	init_list(bittorrent->peers);
 	init_list(bittorrent->peer_pool);
 
+	/* conn->info and conn->done were asserted as NULL above.  */
 	conn->info = bittorrent;
 	conn->done = done_bittorrent_connection;
 

src/protocol/ftp/ftp.c

@@ -678,6 +678,13 @@ add_file_cmd_to_str(struct connection *conn)
 		goto ret;
 	}
 
+	assert(conn->info == NULL);
+	assert(conn->done == NULL);
+	if_assert_failed {
+		abort_connection(conn, S_INTERNAL);
+		goto ret;
+	}
+
 	/* This will be reallocated below when we know how long the
 	 * command string should be.  Error handling could be
 	 * simplified a little by allocating this initial structure on
@@ -689,6 +696,7 @@ add_file_cmd_to_str(struct connection *conn)
 		goto ret;
 	}
 
+	/* conn->info and conn->done were asserted as NULL above.  */
 	conn->info = ftp;	/* Freed when connection is destroyed. */
 
 	if (!init_string(&command)

src/protocol/gopher/gopher.c

@@ -310,6 +310,13 @@ init_gopher_connection_info(struct connection *conn)
 	 * wazzup! */
 	assert(command.length >= 2);
 
+	assert(conn->info == NULL);
+	assert(conn->done == NULL);
+	if_assert_failed {
+		done_string(&command);
+		return S_INTERNAL;
+	}
+
 	size = sizeof(*gopher) + command.length;
 	gopher = mem_calloc(1, size);
 	if (!gopher) {

src/protocol/http/http.c

@@ -523,6 +523,13 @@ init_http_connection_info(struct connection *conn, int major, int minor, int clo
 {
 	struct http_connection_info *http;
 
+	assert(conn->info == NULL);
+	assert(conn->done == NULL);
+	if_assert_failed {
+		http_end_request(conn, S_INTERNAL, 0);
+		return NULL;
+	}
+
 	http = mem_calloc(1, sizeof(*http));
 	if (!http) {
 		http_end_request(conn, S_OUT_OF_MEM, 0);
@@ -547,6 +554,10 @@ init_http_connection_info(struct connection *conn, int major, int minor, int clo
 
 	/* If called from HTTPS proxy connection the connection info might have
 	 * already been allocated. */
+	if (conn->done) {
+		conn->done(conn);
+		conn->done = NULL;
+	}
 	mem_free_set(&conn->info, http);
 
 	return http;

src/protocol/nntp/connection.c

@@ -103,6 +103,13 @@ init_nntp_connection_info(struct connection *conn)
 	unsigned char *data;
 	int datalen;
 
+	assert(conn->info == NULL);
+	assert(conn->done == NULL);
+	if_assert_failed {
+		abort_connection(conn, S_INTERNAL);
+		return NULL;
+	}
+
 	nntp = mem_calloc(1, sizeof(*nntp));
 	if (!nntp) {
 		abort_connection(conn, S_OUT_OF_MEM);
@@ -194,6 +201,13 @@ nntp_quit(struct connection *conn)
 {
 	struct nntp_connection_info *info;
 
+	assert(conn->info == NULL);
+	assert(conn->done == NULL);
+	if_assert_failed {
+		abort_connection(conn, S_INTERNAL);
+		return;
+	}
+
 	info = mem_calloc(1, sizeof(*info));
 	if (!info) {
 		abort_connection(conn, S_OUT_OF_MEM);