configmanager: enhancements for version migration

src/configmanager.cpp

@@ -16,16 +16,20 @@ static const char TAG[] = __FILE__;
 
 Preferences nvram;
 
-static const char cfgMagicBytes[] = {0x21, 0x76, 0x87, 0x32, 0xf3};
+static const uint8_t cfgMagicBytes[] = {0x21, 0x76, 0x87, 0x32, 0xf4};
 static const size_t cfgLen = sizeof(cfg), cfgLen2 = sizeof(cfgMagicBytes);
-static char buffer[cfgLen + cfgLen2];
+static uint8_t buffer[cfgLen + cfgLen2];
 
-// populate runtime config with factory settings
+// populate runtime config with device factory settings
 static void defaultConfig(configData_t *myconfig) {
-  char version[10];
-  snprintf(version, 10, "%-10s", PROGVERSION);
+  // char version[10];
+  // snprintf(version, 10, "%-10s", PROGVERSION);
+  // memcpy(myconfig->version, version, 10); // Firmware version [exactly 10
+  // chars]
+  memcpy(myconfig->version, &PROGVERSION,
+         10); // Firmware version [exactly 10 chars]
 
-  // factory settings
+  // device factory settings
   myconfig->loradr = LORADRDEFAULT; // 0-15, lora datarate, see paxcounter.conf
   myconfig->txpower = LORATXPOWDEFAULT; // 0-15, lora tx power
   myconfig->adrmode = 1;                // 0=disabled, 1=enabled
@@ -43,11 +47,10 @@ static void defaultConfig(configData_t *myconfig) {
   myconfig->blescan = 1;  // 0=disabled, 1=enabled
   myconfig->wifiscan = 1; // 0=disabled, 1=enabled
   myconfig->wifiant = 0;  // 0=internal, 1=external (for LoPy/LoPy4)
-  myconfig->vendorfilter = VENDORFILTER;  // 0=disabled, 1=enabled
-  myconfig->rgblum = RGBLUMINOSITY;       // RGB Led luminosity (0..100%)
-  myconfig->monitormode = 0;              // 0=disabled, 1=enabled
-  myconfig->payloadmask = PAYLOADMASK;    // all payload switched on
-  memcpy(myconfig->version, version, 10); // Firmware version [exactly 10 chars]
+  myconfig->vendorfilter = VENDORFILTER; // 0=disabled, 1=enabled
+  myconfig->rgblum = RGBLUMINOSITY;      // RGB Led luminosity (0..100%)
+  myconfig->monitormode = 0;             // 0=disabled, 1=enabled
+  myconfig->payloadmask = PAYLOADMASK;   // all payload switched on
 
 #ifdef HAS_BME680
   // initial BSEC state for BME680 sensor
@@ -55,6 +58,15 @@ static void defaultConfig(configData_t *myconfig) {
 #endif
 }
 
+// migrate runtime config from earlier version to current
+static void migrateConfig(void) {
+  // currently no migration rules are implemented, we just reset config to
+  // factory settings
+  ESP_LOGI(TAG, "Migrating device configuration from %s to %s", cfg.version,
+           PROGVERSION);
+  eraseConfig();
+}
+
 // save current configuration from RAM to NVRAM
 void saveConfig(bool erase) {
   ESP_LOGI(TAG, "Storing settings to NVRAM...");
@@ -89,30 +101,58 @@ bool loadConfig() {
     ESP_LOGW(TAG, "NVRAM initialized, device starts with factory settings");
     eraseConfig();
     return true;
+  }
 
-  } else {
-    // simple check that runtime config data matches
-    if (nvram.getBytesLength(DEVCONFIG) != (cfgLen + cfgLen2)) {
-      ESP_LOGE(TAG, "configuration invalid");
-      return false;
+  // simple check that runtime config data matches
+  if (nvram.getBytesLength(DEVCONFIG) != (cfgLen + cfgLen2)) {
+    ESP_LOGE(TAG, "Configuration invalid");
+    return false;
+  }
 
-    } else {
-      // load device runtime config from nvram and copy it to byte array
-      nvram.getBytes(DEVCONFIG, buffer, cfgLen + cfgLen2);
-      nvram.end();
-      // validate configuration by checking magic bytes at end of array
-      if (memcmp(buffer + cfgLen, &cfgMagicBytes, cfgLen2) != 0) {
-        ESP_LOGW(TAG, "No configuration found");
-        return false;
+  // load device runtime config from nvram and copy it to byte array
+  nvram.getBytes(DEVCONFIG, buffer, cfgLen + cfgLen2);
+  nvram.end();
 
-      } else {
-        // copy byte array into runtime cfg struct
-        memcpy(&cfg, buffer, cfgLen);
-        ESP_LOGI(TAG, "Runtime configuration loaded");
-        return true;
-      }
-    }
+  // validate loaded configuration by checking magic bytes at end of array
+  if (memcmp(buffer + cfgLen, &cfgMagicBytes, cfgLen2) != 0) {
+    ESP_LOGW(TAG, "No configuration found");
+    return false;
+  }
+
+  // copy loaded configuration into runtime cfg struct
+  memcpy(&cfg, buffer, cfgLen);
+  ESP_LOGI(TAG, "Runtime configuration v%s loaded", cfg.version);
+
+  // check if config version matches current firmware version
+  switch (version_compare(PROGVERSION, cfg.version)) {
+  case -1: // device configuration belongs to newer than current firmware
+    ESP_LOGE(TAG, "Incompatible device configuration, aborting");
+    return false;
+  case 1: // device configuration belongs to older than current firmware
+    ESP_LOGW(TAG, "Device was updated, migrating device configuration");
+    migrateConfig();
+    return true;
+  default: // device configuration version matches current firmware version
+    return true;
   }
 }
 
-void eraseConfig(void) { saveConfig(true); }
+// helper function to convert strings into lower case
+bool comp(char s1, char s2) { return (tolower(s1) < tolower(s2)); }
+
+// helper function to lexicographically compare two versions. Returns 1 if v2
+// is smaller, -1 if v1 is smaller, 0 if equal
+int version_compare(const String v1, const String v2) {
+
+  if (v1 == v2)
+    return 0;
+
+  const char *a1 = v1.c_str(), *a2 = v2.c_str();
+
+  if (std::lexicographical_compare(a1, a1 + strlen(a1), a2, a2 + strlen(a2), comp))
+    return -1;
+  else
+    return 1;
+}
+
+void eraseConfig(void) { saveConfig(true); }

src/ota.cpp

@@ -328,22 +328,4 @@ void show_progress(unsigned long current, unsigned long size) {
 #endif
 }
 
-// helper function to convert strings into lower case
-bool comp(char s1, char s2) { return tolower(s1) < tolower(s2); }
-
-// helper function to lexicographically compare two versions. Returns 1 if v2 is
-// smaller, -1 if v1 is smaller, 0 if equal
-int version_compare(const String v1, const String v2) {
-
-  if (v1 == v2)
-    return 0;
-
-  const char *a1 = v1.c_str(), *a2 = v2.c_str();
-
-  if (lexicographical_compare(a1, a1 + strlen(a1), a2, a2 + strlen(a2), comp))
-    return -1;
-  else
-    return 1;
-}
-
 #endif // USE_OTA