[OpenWrt-Devel] [PATCH 1/7] libubus: refactor ubus_context msgbuf data to be dynamically allocated

[Alexandru Ardelean]

---
 libubus-io.c | 20 +++++++++++++++-----
 libubus.c    | 22 +++++++++++++++++-----
 libubus.h    | 13 ++++++++-----
 3 files changed, 40 insertions(+), 15 deletions(-)

diff --git a/libubus-io.c b/libubus-io.c
index 9a6c7cd..c63a920 100644
--- a/libubus-io.c
+++ b/libubus-io.c
@@ -212,7 +212,7 @@ static int recv_retry(int fd, struct iovec *iov, bool wait, int *recv_fd)
 
 static bool ubus_validate_hdr(struct ubus_msghdr *hdr)
 {
-	struct blob_attr *data = ubus_msghdr_data(hdr);
+	struct blob_attr *data = (struct blob_attr *) (hdr + 1);
 
 	if (hdr->version != 0)
 		return false;
@@ -228,11 +228,14 @@ static bool ubus_validate_hdr(struct ubus_msghdr *hdr)
 
 static bool get_next_msg(struct ubus_context *ctx, int *recv_fd)
 {
-	struct iovec iov = STATIC_IOV(ctx->msgbuf.hdr);
+	struct {
+		struct ubus_msghdr hdr;
+		struct blob_attr data;
+	} hdrbuf;
+	struct iovec iov = STATIC_IOV(hdrbuf);
 	int r;
 
 	/* receive header + start attribute */
-	iov.iov_len += sizeof(struct blob_attr);
 	r = recv_retry(ctx->sock.fd, &iov, false, recv_fd);
 	if (r <= 0) {
 		if (r < 0)
@@ -241,11 +244,18 @@ static bool get_next_msg(struct ubus_context *ctx, int *recv_fd)
 		return false;
 	}
 
-	iov.iov_len = blob_len(ubus_msghdr_data(&ctx->msgbuf.hdr));
+	if (!ubus_validate_hdr(&hdrbuf.hdr))
+		return false;
+
+	memcpy(&ctx->msgbuf.hdr, &hdrbuf.hdr, sizeof(hdrbuf.hdr));
+	memcpy(ctx->msgbuf.data, &hdrbuf.data, sizeof(hdrbuf.data));
+
+	iov.iov_base = (char *)ctx->msgbuf.data + sizeof(hdrbuf.data);
+	iov.iov_len = blob_len(ctx->msgbuf.data);
 	if (iov.iov_len > 0 && !recv_retry(ctx->sock.fd, &iov, true, NULL))
 		return false;
 
-	return ubus_validate_hdr(&ctx->msgbuf.hdr);
+	return true;
 }
 
 void __hidden ubus_handle_data(struct uloop_fd *u, unsigned int events)
diff --git a/libubus.c b/libubus.c
index 1a550c1..83a2c43 100644
--- a/libubus.c
+++ b/libubus.c
@@ -40,7 +40,7 @@ struct blob_buf b __hidden = {};
 
 struct ubus_pending_msg {
 	struct list_head list;
-	struct ubus_msghdr hdr;
+	struct ubus_msghdr_buf hdr;
 };
 
 static int ubus_cmp_id(const void *k1, const void *k2, void *ptr)
@@ -75,11 +75,15 @@ ubus_queue_msg(struct ubus_context *ctx, struct ubus_msghdr *hdr)
 {
 	struct ubus_pending_msg *pending;
 
-	pending = calloc(1, sizeof(*pending) + blob_raw_len(ubus_msghdr_data(hdr)));
+	pending = calloc(1, sizeof(*pending));
 	if (!pending)
 		return;
+	pending->hdr.data = calloc(1, blob_raw_len(ubus_msghdr_data(hdr)));
+	if (!pending->hdr.data)
+		return;
 
-	memcpy(&pending->hdr, hdr, sizeof(*hdr) + blob_raw_len(ubus_msghdr_data(hdr)));
+	memcpy(&pending->hdr.hdr, hdr, sizeof(*hdr));
+	memcpy(pending->hdr.data, ubus_msghdr_data(hdr), blob_raw_len(ubus_msghdr_data(hdr)));
 	list_add(&pending->list, &ctx->pending);
 	if (ctx->sock.registered)
 		uloop_timeout_set(&ctx->pending_timer, 1);
@@ -116,7 +120,8 @@ static void ubus_process_pending_msg(struct uloop_timeout *timeout)
 	while (!ctx->stack_depth && !list_empty(&ctx->pending)) {
 		pending = list_first_entry(&ctx->pending, struct ubus_pending_msg, list);
 		list_del(&pending->list);
-		ubus_process_msg(ctx, &pending->hdr, -1);
+		ubus_process_msg(ctx, &pending->hdr.hdr, -1);
+		free(pending->hdr.data);
 		free(pending);
 	}
 }
@@ -275,11 +280,17 @@ static int _ubus_connect(struct ubus_context *ctx, const char *path)
 	ctx->connection_lost = ubus_default_connection_lost;
 	ctx->pending_timer.cb = ubus_process_pending_msg;
 
+	ctx->msgbuf.data = calloc(UBUS_MAX_MSGLEN, sizeof(char));
+	if (!ctx->msgbuf.data)
+		return -1;
+
 	INIT_LIST_HEAD(&ctx->requests);
 	INIT_LIST_HEAD(&ctx->pending);
 	avl_init(&ctx->objects, ubus_cmp_id, false, NULL);
-	if (ubus_reconnect(ctx, path))
+	if (ubus_reconnect(ctx, path)) {
+		free(ctx->msgbuf.data);
 		return -1;
+	}
 
 	return 0;
 }
@@ -343,5 +354,6 @@ void ubus_free(struct ubus_context *ctx)
 {
 	blob_buf_free(&b);
 	close(ctx->sock.fd);
+	free(ctx->msgbuf.data);
 	free(ctx);
 }
diff --git a/libubus.h b/libubus.h
index 6c560b4..33a99aa 100644
--- a/libubus.h
+++ b/libubus.h
@@ -34,10 +34,16 @@ struct ubus_event_handler;
 struct ubus_subscriber;
 struct ubus_notify_request;
 
+struct ubus_msghdr_buf {
+	struct ubus_msghdr hdr;
+	struct blob_attr *data;
+};
+
 static inline struct blob_attr *
 ubus_msghdr_data(struct ubus_msghdr *hdr)
 {
-	return (struct blob_attr *) (hdr + 1);
+	struct ubus_msghdr_buf *hdrbuf = container_of(hdr, typeof(*hdrbuf), hdr);
+	return hdrbuf->data;
 }
 
 typedef void (*ubus_lookup_handler_t)(struct ubus_context *ctx,
@@ -148,10 +154,7 @@ struct ubus_context {
 
 	void (*connection_lost)(struct ubus_context *ctx);
 
-	struct {
-		struct ubus_msghdr hdr;
-		char data[UBUS_MAX_MSGLEN];
-	} msgbuf;
+	struct ubus_msghdr_buf msgbuf;
 };
 
 struct ubus_object_data {
-- 
1.8.4.5
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