From 9393b12cac9e58f724de63256d56ded7a6e785b1 Mon Sep 17 00:00:00 2001
From: Guillaume Souchere <guillaume.souchere@espressif.com>
Date: Tue, 9 Aug 2022 13:10:44 +0200
Subject: [PATCH 1/2] Add a function hook called in tlsf_check() on every free
 block of memory

In this commit:
- We add a weak delcaration of tlsf_check_hook() in tlsf.h.
- We call tlsf_check_hook() in tlsf_check() if the function has a defintion

This hook function allows the user to implement application specific checks on
the memory of every free blocks (e.g. check for memory corruption).
---
 tlsf.c | 21 ++++++++++++++++++++-
 tlsf.h |  2 ++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/tlsf.c b/tlsf.c
index 189df06..092553b 100644
--- a/tlsf.c
+++ b/tlsf.c
@@ -673,7 +673,8 @@ int tlsf_check(tlsf_t tlsf)
 			while (block != &control->block_null)
 			{
 				int fli, sli;
-				tlsf_insist(block_is_free(block) && "block should be free");
+				const bool is_block_free = block_is_free(block);
+				tlsf_insist(is_block_free && "block should be free");
 				tlsf_insist(!block_is_prev_free(block) && "blocks should have coalesced");
 				tlsf_insist(!block_is_free(block_next(block)) && "blocks should have coalesced");
 				tlsf_insist(block_is_prev_free(block_next(block)) && "block should be free");
@@ -681,6 +682,24 @@ int tlsf_check(tlsf_t tlsf)
 
 				mapping_insert(block_size(block), &fli, &sli);
 				tlsf_insist(fli == i && sli == j && "block size indexed in wrong list");
+
+				if (tlsf_check_hook != NULL)
+				{
+					/* block_size(block) returns the size of the usable memory when the block is allocated.
+					 * As the block under test is free, we need to subtract to the block size the next_free
+					 * and prev_free fields of the block header as they are not a part of the usable memory
+					 * when the block is free. In addition, we also need to subtract the size of prev_phys_block
+					 * as this field is in fact part of the current free block and not part of the next (allocated)
+					 * block. Check the comments in block_split function for more details.
+					 */
+					const size_t actual_free_block_size = block_size(block) 
+															- offsetof(block_header_t, next_free)
+															- block_header_overhead;
+
+					tlsf_insist(tlsf_check_hook((void*)block + sizeof(block_header_t),
+												actual_free_block_size, is_block_free));
+				}
+
 				block = block->next_free;
 			}
 		}
diff --git a/tlsf.h b/tlsf.h
index 2d6cc51..a36017f 100644
--- a/tlsf.h
+++ b/tlsf.h
@@ -64,6 +64,8 @@ int tlsf_check_pool(pool_t pool);
  */
 __attribute__((weak)) void block_absorb_post_hook(void *start, size_t size, bool is_free);
 
+__attribute__((weak)) bool tlsf_check_hook(void *start, size_t size, bool is_free);
+
 #if defined(__cplusplus)
 };
 #endif

From 0fcb10c71aa28854c5515417f4aefd2011de85d6 Mon Sep 17 00:00:00 2001
From: Guillaume Souchere <guillaume.souchere@espressif.com>
Date: Tue, 9 Aug 2022 13:14:11 +0200
Subject: [PATCH 2/2] Remove the call to tlsf_assert in the tlsf_insist maccro

In this commit:
The call to tlsf_asssert is removed from tlsf_insist to allow the tlsf_check()
function to return when one or more of the tlsf_insist() calls fails. In the previous
implementation any failing tlsf_assist() was causing the tlsf_assert to terminate the
execution of the application which doesn't allow the user to handle failures in tlsf_check()
eventhough tlsf_check() returns a value.
---
 tlsf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tlsf.c b/tlsf.c
index 092553b..4255d10 100644
--- a/tlsf.c
+++ b/tlsf.c
@@ -618,7 +618,7 @@ typedef struct integrity_t
 	int status;
 } integrity_t;
 
-#define tlsf_insist(x) { tlsf_assert(x); if (!(x)) { status--; } }
+#define tlsf_insist(x) { if (!(x)) { status--; } }
 
 static void integrity_walker(void* ptr, size_t size, int used, void* user)
 {