From: CoderKang <CoderKang@hotmail.com>
Date: Fri, 19 Sep 2025 10:00:00 +0800
Subject: [PATCH] Add custom GPS location from file

---

diff --git a/services/core/jni/com_android_server_location_GnssLocationProvider.cpp b/services/core/jni/com_android_server_location_GnssLocationProvider.cpp
index a95a4a8..10eae12 100644
--- a/services/core/jni/com_android_server_location_GnssLocationProvider.cpp
+++ b/services/core/jni/com_android_server_location_GnssLocationProvider.cpp
@@ -66,6 +66,9 @@
 #include "jni.h"
 #include "utils/Log.h"
 #include "utils/misc.h"
+#include <fstream>
+#include <sstream>
+#include <sys/stat.h>
 
 static jclass class_gnssPowerStats;
 
@@ -75,6 +78,79 @@ static jmethodID method_isInEmergencySession;
 static jmethodID method_gnssPowerStatsCtor;
 static jmethodID method_setSubHalPowerIndicationCapabilities;
 
+// Custom GPS location from file
+static double customLatitude = 0.0;
+static double customLongitude = 0.0;
+static bool useCustomLocation = false;
+static time_t lastFileModTime = 0;
+static const char* GPS_LOCATION_FILE = "/data/vendor/gps/custom_location.txt";
+
+// Function to read GPS coordinates from file
+static bool readGpsLocationFromFile() {
+    struct stat fileStat;
+    if (stat(GPS_LOCATION_FILE, &fileStat) != 0) {
+        // File doesn't exist, disable custom location
+        useCustomLocation = false;
+        return false;
+    }
+    
+    // Check if file has been modified
+    if (fileStat.st_mtime <= lastFileModTime) {
+        return useCustomLocation; // No change in file
+    }
+    
+    std::ifstream file(GPS_LOCATION_FILE);
+    if (!file.is_open()) {
+        ALOGE("Failed to open GPS location file: %s", GPS_LOCATION_FILE);
+        useCustomLocation = false;
+        return false;
+    }
+    
+    std::string line;
+    if (std::getline(file, line)) {
+        std::istringstream iss(line);
+        std::string latStr, lonStr;
+        
+        // Expected format: "latitude,longitude" or "latitude longitude"
+        if (std::getline(iss, latStr, ',') && std::getline(iss, lonStr)) {
+            // Comma-separated format
+        } else {
+            // Space-separated format
+            iss.clear();
+            iss.str(line);
+            iss >> latStr >> lonStr;
+        }
+        
+        // Use strtod for exception-free parsing
+        char* latEnd;
+        char* lonEnd;
+        double lat = strtod(latStr.c_str(), &latEnd);
+        double lon = strtod(lonStr.c_str(), &lonEnd);
+        
+        // Check if parsing was successful (no leftover characters)
+        if (*latEnd == '\0' && *lonEnd == '\0') {
+            // Validate coordinates
+            if (lat >= -90.0 && lat <= 90.0 && lon >= -180.0 && lon <= 180.0) {
+                customLatitude = lat;
+                customLongitude = lon;
+                useCustomLocation = true;
+                lastFileModTime = fileStat.st_mtime;
+                ALOGI("Custom GPS location loaded: lat=%.6f, lon=%.6f", lat, lon);
+                file.close();
+                return true;
+            } else {
+                ALOGE("Invalid GPS coordinates: lat=%.6f, lon=%.6f", lat, lon);
+            }
+        } else {
+            ALOGE("Failed to parse GPS coordinates from file");
+        }
+    }
+    
+    file.close();
+    useCustomLocation = false;
+    return false;
+}
+
 using android::OK;
 using android::sp;
 using android::status_t;
@@ -377,6 +453,9 @@ static jboolean android_location_gnss_hal_GnssNative_set_position_mode(
 }
 
 static jboolean android_location_gnss_hal_GnssNative_start(JNIEnv* /* env */, jclass) {
+    // Try to read custom GPS location from file when GNSS starts
+    readGpsLocationFromFile();
+    
     return gnssHal->start();
 }
 
@@ -457,12 +536,24 @@ static void android_location_gnss_hal_GnssNative_inject_best_location(
         jfloat speedAccuracyMetersPerSecond, jfloat bearingAccuracyDegrees, jlong timestamp,
         jint elapsedRealtimeFlags, jlong elapsedRealtimeNanos,
         jdouble elapsedRealtimeUncertaintyNanos) {
-    gnssHal->injectBestLocation(gnssLocationFlags, latitudeDegrees, longitudeDegrees,
-                                altitudeMeters, speedMetersPerSec, bearingDegrees,
-                                horizontalAccuracyMeters, verticalAccuracyMeters,
-                                speedAccuracyMetersPerSecond, bearingAccuracyDegrees, timestamp,
-                                elapsedRealtimeFlags, elapsedRealtimeNanos,
-                                elapsedRealtimeUncertaintyNanos);
+    
+    // Check for custom GPS location from file
+    if (readGpsLocationFromFile()) {
+        ALOGI("Using custom GPS location: lat=%.6f, lon=%.6f", customLatitude, customLongitude);
+        gnssHal->injectBestLocation(gnssLocationFlags, customLatitude, customLongitude,
+                                    altitudeMeters, speedMetersPerSec, bearingDegrees,
+                                    horizontalAccuracyMeters, verticalAccuracyMeters,
+                                    speedAccuracyMetersPerSecond, bearingAccuracyDegrees, timestamp,
+                                    elapsedRealtimeFlags, elapsedRealtimeNanos,
+                                    elapsedRealtimeUncertaintyNanos);
+    } else {
+        gnssHal->injectBestLocation(gnssLocationFlags, latitudeDegrees, longitudeDegrees,
+                                    altitudeMeters, speedMetersPerSec, bearingDegrees,
+                                    horizontalAccuracyMeters, verticalAccuracyMeters,
+                                    speedAccuracyMetersPerSecond, bearingAccuracyDegrees, timestamp,
+                                    elapsedRealtimeFlags, elapsedRealtimeNanos,
+                                    elapsedRealtimeUncertaintyNanos);
+    }
 }
 
 static void android_location_gnss_hal_GnssNative_inject_location(
@@ -472,11 +563,22 @@ static void android_location_gnss_hal_GnssNative_inject_location(
         jfloat speedAccuracyMetersPerSecond, jfloat bearingAccuracyDegrees, jlong timestamp,
         jint elapsedRealtimeFlags, jlong elapsedRealtimeNanos,
         jdouble elapsedRealtimeUncertaintyNanos) {
-    gnssHal->injectLocation(gnssLocationFlags, latitudeDegrees, longitudeDegrees, altitudeMeters,
-                            speedMetersPerSec, bearingDegrees, horizontalAccuracyMeters,
-                            verticalAccuracyMeters, speedAccuracyMetersPerSecond,
-                            bearingAccuracyDegrees, timestamp, elapsedRealtimeFlags,
-                            elapsedRealtimeNanos, elapsedRealtimeUncertaintyNanos);
+    
+    // Check for custom GPS location from file
+    if (readGpsLocationFromFile()) {
+        ALOGI("Using custom GPS location: lat=%.6f, lon=%.6f", customLatitude, customLongitude);
+        gnssHal->injectLocation(gnssLocationFlags, customLatitude, customLongitude, altitudeMeters,
+                                speedMetersPerSec, bearingDegrees, horizontalAccuracyMeters,
+                                verticalAccuracyMeters, speedAccuracyMetersPerSecond,
+                                bearingAccuracyDegrees, timestamp, elapsedRealtimeFlags,
+                                elapsedRealtimeNanos, elapsedRealtimeUncertaintyNanos);
+    } else {
+        gnssHal->injectLocation(gnssLocationFlags, latitudeDegrees, longitudeDegrees, altitudeMeters,
+                                speedMetersPerSec, bearingDegrees, horizontalAccuracyMeters,
+                                verticalAccuracyMeters, speedAccuracyMetersPerSecond,
+                                bearingAccuracyDegrees, timestamp, elapsedRealtimeFlags,
+                                elapsedRealtimeNanos, elapsedRealtimeUncertaintyNanos);
+    }
 }
 
 static jboolean android_location_gnss_hal_GnssNative_supports_psds(JNIEnv* /* env */, jclass) {