configmanager: enhancements for version migration

include/configmanager.h

@@ -1,11 +1,12 @@
 #ifndef _CONFIGMANAGER_H
 #define _CONFIGMANAGER_H
 
-#include <Preferences.h>
 #include "globals.h"
+#include <Preferences.h>
 
 void saveConfig(bool erase = false);
 bool loadConfig(void);
 void eraseConfig(void);
+int version_compare(const String v1, const String v2);
 
 #endif

include/globals.h

@@ -60,8 +60,10 @@ enum runmode_t {
 };
 
 // Struct holding devices's runtime configuration
-// using packed to avoid compiler padding, because struct will be memcpy'd to byte array
+// using packed to avoid compiler padding, because struct will be memcpy'd to
+// byte array
 typedef struct __attribute__((packed)) {
+  char version[10];    // Firmware version
   uint8_t loradr;      // 0-15, lora datarate
   uint8_t txpower;     // 2-15, lora tx power
   uint8_t adrmode;     // 0=disabled, 1=enabled
@@ -80,7 +82,6 @@ typedef struct __attribute__((packed)) {
   uint8_t monitormode;   // 0=disabled, 1=enabled
   uint8_t runmode;       // 0=normal, 1=update
   uint8_t payloadmask;   // bitswitches for payload data
-  char version[10];      // Firmware version
 #ifdef HAS_BME680
   uint8_t
       bsecstate[BSEC_MAX_STATE_BLOB_SIZE + 1]; // BSEC state for BME680 sensor

include/ota.h

@@ -6,17 +6,15 @@
 #include "globals.h"
 #include "led.h"
 #include "display.h"
+#include "configmanager.h"
 
 #include <Update.h>
 #include <WiFi.h>
 #include <WiFiClientSecure.h>
 #include <BintrayClient.h>
-#include <string>
-#include <algorithm>
 
 int do_ota_update();
 void start_ota_update();
-int version_compare(const String v1, const String v2);
 void ota_display(const uint8_t row, const std::string status,
                  const std::string msg);
 void show_progress(unsigned long current, unsigned long size);

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
@@ -47,7 +51,6 @@ static void defaultConfig(configData_t *myconfig) {
   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]
 
 #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");
+    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
+
+  // 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;
+  }
 
-      } else {
-        // copy byte array into runtime cfg struct
+  // copy loaded configuration into runtime cfg struct
   memcpy(&cfg, buffer, cfgLen);
-        ESP_LOGI(TAG, "Runtime configuration loaded");
+  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;
   }
 }
-  }
+
+// 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