feat(app_update): add app description data and its functions

components/app_update/esp_app_desc.c

@@ -0,0 +1,85 @@
+// Copyright 2017-2018 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <assert.h>
+#include <sys/param.h>
+#include "esp_ota_ops.h"
+#include "esp_attr.h"
+#include "sdkconfig.h"
+
+// Application version info
+const __attribute__((section(".rodata_desc"))) esp_app_desc_t esp_app_desc = {
+    .magic_word = ESP_APP_DESC_MAGIC_WORD,
+#ifdef CONFIG_APP_EXCLUDE_PROJECT_VER_VAR
+    .version = "",
+#else
+    .version = PROJECT_VER,
+#endif
+
+#ifdef CONFIG_APP_EXCLUDE_PROJECT_NAME_VAR
+    .project_name = "",
+#else
+    .project_name = PROJECT_NAME,
+#endif
+    .idf_ver = IDF_VER,
+
+#ifdef CONFIG_BOOTLOADER_APP_SECURE_VERSION
+    .secure_version = CONFIG_BOOTLOADER_APP_SECURE_VERSION,
+#else
+    .secure_version = 0,
+#endif
+
+#ifdef CONFIG_APP_COMPILE_TIME_DATE
+    .time = __TIME__,
+    .date = __DATE__,
+#else
+    .time = "",
+    .date = "",
+#endif
+};
+
+
+#ifndef CONFIG_APP_EXCLUDE_PROJECT_VER_VAR
+_Static_assert(sizeof(PROJECT_VER) <= sizeof(esp_app_desc.version), "PROJECT_VER is longer than version field in structure");
+#endif
+_Static_assert(sizeof(IDF_VER) <= sizeof(esp_app_desc.idf_ver), "IDF_VER is longer than idf_ver field in structure");
+#ifndef CONFIG_APP_EXCLUDE_PROJECT_NAME_VAR
+_Static_assert(sizeof(PROJECT_NAME) <= sizeof(esp_app_desc.project_name), "PROJECT_NAME is longer than project_name field in structure");
+#endif
+
+const esp_app_desc_t *esp_ota_get_app_description(void)
+{
+    return &esp_app_desc;
+}
+
+/* The following two functions may be called from the panic handler
+ * or core dump, hence IRAM_ATTR.
+ */
+
+static inline char to_hex_digit(unsigned val)
+{
+    return (val < 10) ? ('0' + val) : ('a' + val - 10);
+}
+
+int esp_ota_get_app_elf_sha256(char* dst, size_t size)
+{
+    size_t n = MIN((size - 1) / 2, sizeof(esp_app_desc.app_elf_sha256));
+    const uint8_t* src = esp_app_desc.app_elf_sha256;
+    for (size_t i = 0; i < n; ++i) {
+        dst[2*i] = to_hex_digit(src[i] >> 4);
+        dst[2*i + 1] = to_hex_digit(src[i] & 0xf);
+    }
+    dst[2*n] = 0;
+    return 2*n + 1;
+}