From a72f2e22571e400cfe84b8f4c64f7fb048723a86 Mon Sep 17 00:00:00 2001
From: 0xFEEDC0DE64 <daniel@brunner.ninja>
Date: Sun, 28 Feb 2021 15:23:26 +0100
Subject: [PATCH] coredump: Implemented esp_core_dump_image_erase() and
 esp_core_dump_image_get() now returns ESP_ERR_NOT_FOUND when partition is
 blank

Closes https://github.com/espressif/esp-idf/pull/6631
---
 .../espcoredump/include/esp_core_dump.h       |  9 +++++
 components/espcoredump/src/core_dump_flash.c  | 38 ++++++++++++++++++-
 2 files changed, 45 insertions(+), 2 deletions(-)

diff --git a/components/espcoredump/include/esp_core_dump.h b/components/espcoredump/include/esp_core_dump.h
index fb0d44d2c810..0272754771a8 100644
--- a/components/espcoredump/include/esp_core_dump.h
+++ b/components/espcoredump/include/esp_core_dump.h
@@ -89,6 +89,15 @@ void esp_core_dump_to_uart(panic_info_t *info);
  */
 esp_err_t esp_core_dump_image_get(size_t* out_addr, size_t *out_size);
 
+/**
+ * @brief  Erases coredump data in flash. esp_core_dump_image_get() will then return
+ *         ESP_ERR_NOT_FOUND. Can be used after a coredump has been transmitted successfully.
+ *         This function is always available, even when core dump is disabled in menuconfig.
+ *
+ * @return ESP_OK on success, otherwise \see esp_err_t
+ */
+esp_err_t esp_core_dump_image_erase();
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/components/espcoredump/src/core_dump_flash.c b/components/espcoredump/src/core_dump_flash.c
index cf63d7539fa2..0a6c173d619a 100644
--- a/components/espcoredump/src/core_dump_flash.c
+++ b/components/espcoredump/src/core_dump_flash.c
@@ -392,8 +392,8 @@ esp_err_t esp_core_dump_image_get(size_t* out_addr, size_t *out_size)
 
     /* Verify that the size read from the flash is not corrupted. */
     if (size == 0xFFFFFFFF) {
-        ESP_LOGD(TAG, "Blank core dump partition!");
-        err = ESP_ERR_INVALID_SIZE;
+        ESP_LOGD(TAG, "Coredump not found, blank core dump partition!");
+        err = ESP_ERR_NOT_FOUND;
     } else if ((size < sizeof(uint32_t)) || (size > core_part->size)) {
         ESP_LOGE(TAG, "Incorrect size of core dump image: %d", size);
         err = ESP_ERR_INVALID_SIZE;
@@ -459,3 +459,37 @@ esp_err_t esp_core_dump_image_get(size_t* out_addr, size_t *out_size)
 }
 
 #endif
+
+esp_err_t esp_core_dump_image_erase()
+{
+    /* Find the partition that could potentially contain a (previous) core dump. */
+    const esp_partition_t *core_part = esp_partition_find_first(ESP_PARTITION_TYPE_DATA,
+                                                                ESP_PARTITION_SUBTYPE_DATA_COREDUMP,
+                                                                NULL);
+    if (!core_part) {
+        ESP_LOGE(TAG, "No core dump partition found!");
+        return ESP_ERR_NOT_FOUND;
+    }
+    if (core_part->size < sizeof(uint32_t)) {
+        ESP_LOGE(TAG, "Too small core dump partition!");
+        return ESP_ERR_INVALID_SIZE;
+    }
+
+    esp_err_t err = ESP_OK;
+    err = esp_partition_erase_range(core_part, 0, core_part->size);
+    if (err != ESP_OK) {
+        ESP_LOGE(TAG, "Failed to erase core dump partition (%d)!", err);
+        return err;
+    }
+
+    // on encrypted flash esp_partition_erase_range will leave encrypted
+    // garbage instead of 0xFFFFFFFF so overwriting again to safely signalize
+    // deleted coredumps
+    const uint32_t invalid_size = 0xFFFFFFFF;
+    err = esp_partition_write(core_part, 0, &invalid_size, sizeof(invalid_size));
+    if (err != ESP_OK) {
+        ESP_LOGE(TAG, "Failed to write core dump partition size (%d)!", err);
+    }
+
+    return err;
+}