From 4598057553e67c999a279f8c47f40eb84ff98258 Mon Sep 17 00:00:00 2001
From: Max Wash <mbswash@gmail.com>
Date: Mon, 24 Feb 2025 15:46:27 +0000
Subject: [PATCH] each tag ioctx now keeps its own copy of the ec3_tag_info
 describing it

this fixes an issue where pointers to ec3_tag_info would become
invalid when the b_buffer containing them was resized.
---
 src/image.c | 10 +++++-----
 src/image.h |  8 --------
 src/tag.c   |  4 ++--
 src/tag.h   | 10 +++++++++-
 4 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/src/image.c b/src/image.c
index 1fd0ea3..8900320 100644
--- a/src/image.c
+++ b/src/image.c
@@ -16,12 +16,12 @@ B_BTREE_DEFINE_SIMPLE_GET(
 	struct ec3_tag_ioctx,
 	uint64_t,
 	io_node,
-	io_tag_info->tag_ident,
+	io_tag_info.tag_ident,
 	get_opened_tag)
 B_BTREE_DEFINE_SIMPLE_INSERT(
 	struct ec3_tag_ioctx,
 	io_node,
-	io_tag_info->tag_ident,
+	io_tag_info.tag_ident,
 	put_opened_tag)
 
 static enum ec3_status decode_header(
@@ -729,7 +729,7 @@ enum ec3_status ec3_image_ioctx_open_tag_by_type(
 
 	tag_ioctx->io_mode = mode;
 	tag_ioctx->io_parent = image;
-	tag_ioctx->io_tag_info = tag_info;
+	tag_ioctx->io_tag_info = *tag_info;
 	tag_ioctx->io_f_image = b_file_retain(image->io_main);
 
 	if (mode & EC3_TAG_IO_WRITE) {
@@ -791,7 +791,7 @@ enum ec3_status ec3_image_ioctx_open_tag_by_id(
 
 	tag_ioctx->io_mode = mode;
 	tag_ioctx->io_parent = image;
-	tag_ioctx->io_tag_info = tag_info;
+	tag_ioctx->io_tag_info = *tag_info;
 	tag_ioctx->io_f_image = b_file_retain(image->io_main);
 
 	if (mode & EC3_TAG_IO_WRITE) {
@@ -862,7 +862,7 @@ enum ec3_status ec3_image_ioctx_create_tag(
 
 	tag_ioctx->io_mode = mode;
 	tag_ioctx->io_parent = image;
-	tag_ioctx->io_tag_info = tag_info;
+	tag_ioctx->io_tag_info = *tag_info;
 	tag_ioctx->io_f_image = b_file_retain(image->io_main);
 
 	status = init_tag_ioctx_create(image, tag_info, tag_ioctx);
diff --git a/src/image.h b/src/image.h
index 7700eae..691d031 100644
--- a/src/image.h
+++ b/src/image.h
@@ -44,14 +44,6 @@ struct ec3_image_info {
 	uint64_t img_id;
 };
 
-struct ec3_tag_info {
-	unsigned long tag_type;
-	unsigned long tag_flags;
-	unsigned long tag_checksum;
-	unsigned long long tag_ident;
-	unsigned long long tag_total_length;
-};
-
 struct ec3_extent_info {
 	unsigned long long ex_owner;
 	unsigned long ex_logical_cluster;
diff --git a/src/tag.c b/src/tag.c
index 0582c9a..9e41f0a 100644
--- a/src/tag.c
+++ b/src/tag.c
@@ -142,7 +142,7 @@ enum ec3_status ec3_tag_ioctx_read_cluster(
 	size_t physical_cluster_id = 0;
 	status = ec3_image_ioctx_cluster_logical_to_physical(
 		tag->io_parent,
-		tag->io_tag_info,
+		&tag->io_tag_info,
 		cluster_id,
 		&physical_cluster_id);
 
@@ -276,7 +276,7 @@ enum ec3_status ec3_tag_ioctx_get_nr_clusters(
 
 	for (size_t i = 0; i < nr_extents; i++) {
 		const struct ec3_extent_info *x = &extents[i];
-		if (x->ex_owner != tag->io_tag_info->tag_ident) {
+		if (x->ex_owner != tag->io_tag_info.tag_ident) {
 			continue;
 		}
 
diff --git a/src/tag.h b/src/tag.h
index 09b9595..6e86cbb 100644
--- a/src/tag.h
+++ b/src/tag.h
@@ -20,6 +20,14 @@ enum ec3_tag_ioctx_mode {
 	EC3_TAG_IO_CLOSED = 0x10u,
 };
 
+struct ec3_tag_info {
+	unsigned long tag_type;
+	unsigned long tag_flags;
+	unsigned long tag_checksum;
+	unsigned long long tag_ident;
+	unsigned long long tag_total_length;
+};
+
 struct ec3_tag_ioctx {
 	struct ec3_image_ioctx *io_parent;
 	b_btree_node io_node;
@@ -32,7 +40,7 @@ struct ec3_tag_ioctx {
 	size_t io_cluster_data_offset;
 
 	/* this points to memory belonging to ec3_image_ioctx */
-	const struct ec3_tag_info *io_tag_info;
+	struct ec3_tag_info io_tag_info;
 
 	/* io_f_rotag is a reference to the main image file. a data and cluster
 	 * table offset will be used to read clusters from the image if the tag