From 5d2e255bea1070cdb6f9fd5c48889384e2f4f51a Mon Sep 17 00:00:00 2001
From: Kyle Isom <kyle@imap.cc>
Date: Thu, 5 Oct 2023 20:49:17 -0700
Subject: [PATCH] fix record deletion

- also zero out rest of record when setting
---
 Arena.cc    |  2 +-
 TLV.cc      | 20 +++++++++++++++-----
 tlv_test.cc |  6 +++++-
 3 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/Arena.cc b/Arena.cc
index ce75e95..f77c075 100644
--- a/Arena.cc
+++ b/Arena.cc
@@ -107,7 +107,7 @@ create_arena(Arena &arena, const char *path, size_t size, mode_t mode)
 		}
 	}
 
-	fd = open(path, O_WRONLY|O_CREAT, mode);
+	fd = open(path, O_WRONLY|O_CREAT|O_TRUNC, mode);
 	if (fd == -1) {
 		return -1;
 	}
diff --git a/TLV.cc b/TLV.cc
index f0b852d..bf52f4a 100644
--- a/TLV.cc
+++ b/TLV.cc
@@ -53,9 +53,12 @@ write_to_memory(Arena &arena, uint8_t *cursor, Record &rec)
 void	
 set_record(Record &rec, uint8_t tag, uint8_t len, const char *val)
 {
+	uint8_t	trail = TLV_MAX_LEN-len;
+
 	rec.Tag = tag;
 	rec.Len = len;
 	memcpy(rec.Val, val, len);
+	memset(rec.Val+len, 0, trail);
 }
 
 
@@ -127,14 +130,21 @@ delete_record(Arena &arena, uint8_t *cursor)
 		return;
 	}
 
-	uintptr_t	len = cursor[1] + 2;
-	uintptr_t	stop = (uintptr_t)arena.size - (uintptr_t)cursor;
+	uint8_t	 	 len = cursor[1] + 2;
+	uint8_t		*stop = arena.store + arena.size;
 
 	stop -= len;
 
-	for (uintptr_t i = (uintptr_t)cursor; i < stop; i++) {
-		cursor[i] = cursor[i+len];
-	};
+	while (cursor != stop) {
+		cursor[0] = cursor[len];
+		cursor++;
+	}
+
+	stop += len;
+	while (cursor != stop) {
+		cursor[0] = 0;
+		cursor++;
+	}
 }
 
 
diff --git a/tlv_test.cc b/tlv_test.cc
index 54f113a..f021c3e 100644
--- a/tlv_test.cc
+++ b/tlv_test.cc
@@ -60,8 +60,12 @@ tlv_test_suite(Arena &backend)
 	TLV::set_record(rec4, 3, TEST_STRLEN3, TEST_STR3);
 	assert(TLV::write_to_memory(backend, NULL, rec4));
 
+	rec4.Tag = 2;
+	cursor = TLV::find_tag(backend, NULL, rec4);
+	assert(cursor != NULL);
+
 	TLV::delete_record(backend, cursor);
-	assert(cursor[0] == TAG_EMPTY);
+	assert(cursor[0] == 3);
 
 	return true;
 }