variants/linux: GPS from a serial device or gpsd, and host-clock discipline

platformio.ini

@@ -224,6 +224,13 @@ test_framework = googletest
 build_flags = -std=c++17
   -I src
   -I test/mocks
+  -I variants/linux
+; MicroNMEA is reached only from a test file, and a lib_deps entry that nothing
+; under build_src_filter includes gets neither its include dir onto the test
+; compile line nor its archive onto the link line (verified: dropping either of
+; the two lines below fails, the first to compile and the second to link). So
+; name both explicitly; lib_deps still pins the version and fetches it.
+  -I .pio/libdeps/native/MicroNMEA/src
 test_build_src = yes
 test_ignore = test_kiss_modem
 build_src_filter =
@@ -232,8 +239,13 @@ build_src_filter =
   +<../src/Packet.cpp>
   +<../src/helpers/ConfigSerializer.cpp>
   +<../src/helpers/DynamicConfigSerializer.cpp>
+  +<../variants/linux/LinuxGpsStream.cpp>
+  +<../.pio/libdeps/native/MicroNMEA/src/MicroNMEA.cpp>
 lib_deps =
   google/googletest @ 1.17.0
+; test_linux_gps_stream includes <MicroNMEA.h> to prove with the real parser
+; that gpsd's JSON control lines cannot corrupt a fix.
+  stevemarple/MicroNMEA @ ^2.0.6
 
 [env:native_kiss_modem]
 platform = native

src/helpers/CommonCLI.cpp

@@ -19,6 +19,17 @@ static uint32_t _atoi(const char* sp) {
   return n;
 }
 
+// setCurrentTime() returns void, so this is the only signal available that a
+// set was honoured. On Linux it can be silently refused (host clock owned by
+// chrony, or the process lacks CAP_SYS_TIME) and getCurrentTime() then reads
+// back the unchanged clock; on every other target the set always takes, so
+// this is always true there. A couple of seconds of slack absorbs a hardware
+// RTC's read-back latency, not a real failure.
+static bool clockSetTookEffect(uint32_t target, uint32_t actual) {
+  int64_t diff = (int64_t)actual - (int64_t)target;
+  return diff >= -2 && diff <= 2;
+}
+
 static bool isValidName(const char *n) {
   while (*n) {
     if (*n == '[' || *n == ']' || *n == '\\' || *n == ':' || *n == ',' || *n == '?' || *n == '*') return false;
@@ -210,10 +221,15 @@ void CommonCLI::handleCommand(uint32_t sender_timestamp, char* command, char* re
     } else if (memcmp(command, "clock sync", 10) == 0) {
       uint32_t curr = getRTCClock()->getCurrentTime();
       if (sender_timestamp > curr) {
-        getRTCClock()->setCurrentTime(sender_timestamp + 1);
+        uint32_t target = sender_timestamp + 1;
+        getRTCClock()->setCurrentTime(target);
         uint32_t now = getRTCClock()->getCurrentTime();
-        DateTime dt = DateTime(now);
-        sprintf(reply, "OK - clock set: %02d:%02d - %d/%d/%d UTC", dt.hour(), dt.minute(), dt.day(), dt.month(), dt.year());
+        if (clockSetTookEffect(target, now)) {
+          DateTime dt = DateTime(now);
+          sprintf(reply, "OK - clock set: %02d:%02d - %d/%d/%d UTC", dt.hour(), dt.minute(), dt.day(), dt.month(), dt.year());
+        } else {
+          strcpy(reply, "ERR: clock set was refused");
+        }
       } else {
         strcpy(reply, "ERR: clock cannot go backwards");
       }
@@ -231,8 +247,12 @@ void CommonCLI::handleCommand(uint32_t sender_timestamp, char* command, char* re
       if (secs > curr) {
         getRTCClock()->setCurrentTime(secs);
         uint32_t now = getRTCClock()->getCurrentTime();
-        DateTime dt = DateTime(now);
-        sprintf(reply, "OK - clock set: %02d:%02d - %d/%d/%d UTC", dt.hour(), dt.minute(), dt.day(), dt.month(), dt.year());
+        if (clockSetTookEffect(secs, now)) {
+          DateTime dt = DateTime(now);
+          sprintf(reply, "OK - clock set: %02d:%02d - %d/%d/%d UTC", dt.hour(), dt.minute(), dt.day(), dt.month(), dt.year());
+        } else {
+          strcpy(reply, "(ERR: clock set was refused)");
+        }
       } else {
         strcpy(reply, "(ERR: clock cannot go backwards)");
       }
@@ -396,7 +416,11 @@ void CommonCLI::handleCommand(uint32_t sender_timestamp, char* command, char* re
         bool enabled = l->isEnabled(); // is EN pin on ?
         bool fix = l->isValid();       // has fix ?
         int sats = l->satellitesCount();
-        bool active = !strcmp(_sensors->getSettingByKey("gps"), "1");
+        // getSettingByKey() returns NULL when no "gps" setting is registered
+        // (e.g. no GPS detected -- the Linux default) -- treat that as
+        // "deactivated" rather than handing strcmp() a NULL, which segfaults.
+        const char* gps_setting = _sensors->getSettingByKey("gps");
+        bool active = gps_setting != NULL && strcmp(gps_setting, "1") == 0;
         if (enabled) {
           sprintf(reply, "on, %s, %s, %d sats",
             active?"active":"deactivated",

src/helpers/sensors/EnvironmentSensorManager.cpp

@@ -747,8 +747,25 @@ bool EnvironmentSensorManager::setSettingValue(const char* name, const char* val
 }
 
 #if ENV_INCLUDE_GPS
+#if defined(ARDULINUX_PLATFORM)
+// Defined in variants/linux/target.cpp. The Linux build opens the serial GPS
+// device itself (there is no hardware UART); this reports whether that device
+// is open.
+bool linux_gps_present();
+#endif
+
 void EnvironmentSensorManager::initBasicGPS() {
 
+#if defined(ARDULINUX_PLATFORM)
+  // Linux: the serial device is opened by the variant (target.cpp) from the
+  // gps_device/gps_baud config. A configured+opened device is treated as
+  // detected (no byte-sniff, which raced against slow-to-fix devices);
+  // runtime loop()/isValid() reports actual fix state. If nothing was
+  // configured/opened, GPS is off.
+  _location->begin();   // no-op on Linux (pin_en/pin_reset == -1)
+  _location->reset();
+  gps_detected = linux_gps_present();
+#else
   Serial1.setPins(PIN_GPS_TX, PIN_GPS_RX);
 
   #ifdef GPS_BAUD_RATE
@@ -774,6 +791,7 @@ void EnvironmentSensorManager::initBasicGPS() {
 #else
   gps_detected = (Serial1.available() > 0);
 #endif
+#endif  // ARDULINUX_PLATFORM
 
   if (gps_detected) {
     MESH_DEBUG_PRINTLN("GPS detected");

src/helpers/sensors/LocationProvider.h

@@ -16,7 +16,7 @@ class LocationProvider {
     virtual long satellitesCount() = 0;
     virtual bool isValid() = 0;
     virtual long getTimestamp() = 0;
-    virtual void sendSentence(const char * sentence);
+    virtual void sendSentence(const char * sentence) {}
     virtual void reset() = 0;
     virtual void begin() = 0;
     virtual void stop() = 0;

test/mocks/Arduino.h

@@ -2,6 +2,7 @@
 
 #include <cstdint>
 #include <cmath>
+#include <cctype>   // real Arduino.h pulls this in; MicroNMEA relies on it
 #include "Stream.h"
 
 inline uint32_t g_mock_millis = 0;

test/mocks/Mesh.h

@@ -25,3 +25,9 @@ class MainBoard {
 };
 
 }
+
+// LinuxGpsStream.cpp logs through this. The real definition lives in
+// src/MeshCore.h, which the native test env does not build.
+#ifndef MESH_DEBUG_PRINTLN
+  #define MESH_DEBUG_PRINTLN(...) {}
+#endif