From 0ea0c86753ea55123da51cfce3276792e124f2e4 Mon Sep 17 00:00:00 2001
From: Christopher Faulet <cfaulet@haproxy.com>
Date: Thu, 23 Jan 2020 11:47:53 +0100
Subject: [PATCH] MINOR: htx: Add a function to append an HTX message to
 another one

the htx_append_msg() function can now be used to append an HTX message to
another one. All the message is copied or nothing. If an error occurs during the
copy, all changes are rolled back.

This patch is mandatory to fix a bug in http_reply_and_close() function. Be
careful to backport it first.
---
 include/common/htx.h |  1 +
 src/htx.c            | 31 +++++++++++++++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/include/common/htx.h b/include/common/htx.h
index b22da99b4..11caa59bf 100644
--- a/include/common/htx.h
+++ b/include/common/htx.h
@@ -255,6 +255,7 @@ struct htx_blk *htx_add_data_atonce(struct htx *htx, struct ist data);
 size_t htx_add_data(struct htx *htx, const struct ist data);
 struct htx_blk *htx_add_last_data(struct htx *htx, struct ist data);
 void htx_move_blk_before(struct htx *htx, struct htx_blk **blk, struct htx_blk **ref);
+int htx_append_msg(struct htx *dst, const struct htx *src);
 
 /* Functions and macros to get parts of the start-line or legnth of these
  * parts. Request and response start-lines are both composed of 3 parts.
diff --git a/src/htx.c b/src/htx.c
index 139f3c096..41eb47274 100644
--- a/src/htx.c
+++ b/src/htx.c
@@ -1040,3 +1040,34 @@ void htx_move_blk_before(struct htx *htx, struct htx_blk **blk, struct htx_blk *
 	*blk = cblk;
 	*ref = pblk;
 }
+
+/* Append the HTX message <src> to the HTX message <dst>. It returns 1 on
+ * success and 0 on error.  All the message or nothing is copied. If an error
+ * occurred, all blocks from <src> already appended to <dst> are truncated.
+ */
+int htx_append_msg(struct htx *dst, const struct htx *src)
+{
+	struct htx_blk *blk, *newblk;
+	enum htx_blk_type type;
+	uint32_t blksz, offset = dst->data;
+
+	for (blk = htx_get_head_blk(src); blk; blk = htx_get_next_blk(src, blk)) {
+		type = htx_get_blk_type(blk);
+
+		if (type == HTX_BLK_UNUSED)
+			continue;
+
+		blksz = htx_get_blksz(blk);
+		newblk = htx_add_blk(dst, type, blksz);
+		if (!newblk)
+			goto error;
+		newblk->info = blk->info;
+		memcpy(htx_get_blk_ptr(dst, newblk), htx_get_blk_ptr(src, blk), blksz);
+	}
+
+	return 1;
+
+  error:
+	htx_truncate(dst, offset);
+	return 0;
+}