Read Xposed version from xposed.prop instead of constant

The Xposed framework consists of several parts: app_process, XposedBridge.jar
and the modified ART runtime. Let's use a single version number for the whole
package, defined in /system/xposed.prop, instead of having different version
numbers for the individual parts. It's not supported to mix parts from
different packages anyway.

app_main.cpp

@@ -34,7 +34,7 @@ void app_usage()
 {
     fprintf(stderr,
         "Usage: app_process [java-options] cmd-dir start-class-name [options]\n");
-    fprintf(stderr, "   with Xposed support (version " XPOSED_VERSION ")\n");
+    fprintf(stderr, "   with Xposed support\n");
 }
 
 void _atrace_set_tracing_enabled(bool enabled)

app_main2.cpp

@@ -33,7 +33,7 @@ static void app_usage()
 {
     fprintf(stderr,
         "Usage: app_process [java-options] cmd-dir start-class-name [options]\n");
-    fprintf(stderr, "   with Xposed support (version " XPOSED_VERSION ")\n");
+    fprintf(stderr, "   with Xposed support\n");
 }
 
 class AppRuntime : public AndroidRuntime

xposed.cpp

@@ -9,12 +9,13 @@
 #include "xposed_safemode.h"
 #include "xposed_service.h"
 
-#include <stdlib.h>
+#include <ctype.h>
 #include <cutils/process_name.h>
 #include <cutils/properties.h>
-#include <fcntl.h>
 #include <dlfcn.h>
 #include <errno.h>
+#include <fcntl.h>
+#include <stdlib.h>
 
 #if PLATFORM_SDK_VERSION >= 18
 #include <sys/capability.h>
@@ -33,15 +34,19 @@ static int sdkVersion = -1;
 static char* argBlockStart;
 static size_t argBlockLength;
 
+const char* xposedVersion = "unknown (invalid " XPOSED_PROP_FILE ")";
+uint32_t xposedVersionInt = 0;
 
 ////////////////////////////////////////////////////////////
 // Functions
 ////////////////////////////////////////////////////////////
 
 /** Handle special command line options. */
 bool handleOptions(int argc, char* const argv[]) {
+    parseXposedProp();
+
     if (argc == 2 && strcmp(argv[1], "--xposedversion") == 0) {
-        printf("Xposed version: " XPOSED_VERSION "\n");
+        printf("Xposed version: %s\n", xposedVersion);
         return true;
     }
 
@@ -140,7 +145,7 @@ void printRomInfo() {
     property_get("ro.product.cpu.abi", platform, "n/a");
 
     ALOGI("-----------------");
-    ALOGI("Starting Xposed binary version %s, compiled for SDK %d", XPOSED_VERSION, PLATFORM_SDK_VERSION);
+    ALOGI("Starting Xposed version %s, compiled for SDK %d", xposedVersion, PLATFORM_SDK_VERSION);
     ALOGI("Device: %s (%s), Android version %s (SDK %s)", model, manufacturer, release, sdk);
     ALOGI("ROM: %s", rom);
     ALOGI("Build fingerprint: %s", fingerprint);
@@ -153,6 +158,58 @@ void printRomInfo() {
             xposed->isSELinuxEnforcing ? "yes" : "no");
 }
 
+/** Parses /system/xposed.prop and stores selected values in variables */
+void parseXposedProp() {
+    FILE *fp = fopen(XPOSED_PROP_FILE, "r");
+    if (fp == NULL) {
+        ALOGE("Could not read %s: %s", XPOSED_PROP_FILE, strerror(errno));
+        return;
+    }
+
+    char buf[512];
+    while (fgets(buf, sizeof(buf), fp) != NULL) {
+        char* key = buf;
+        // Ignore leading spaces for the key
+        while (isspace(*key)) key++;
+
+        // Skip comments
+        if (*key == '#')
+            continue;
+
+        // Find the key/value separator
+        char* value = strchr(buf, '=');
+        if (value == NULL)
+            continue;
+
+        // Ignore trailing spaces for the key
+        char* tmp = value;
+        do { *tmp = 0; tmp--; } while (isspace(*tmp));
+
+        // Ignore leading spaces for the value
+        do { value++; } while (isspace(*value));
+
+        // Remove trailing newline
+        tmp = strpbrk(value, "\n\r");
+        if (tmp != NULL)
+            *tmp = 0;
+
+        // Handle this entry
+        if (!strcmp("version", key)) {
+            int len = strlen(value);
+            if (len == 0)
+                continue;
+            tmp = (char*) malloc(len + 1);
+            strlcpy(tmp, value, len + 1);
+            xposedVersion = tmp;
+            xposedVersionInt = atoi(xposedVersion);
+        }
+    }
+    fclose(fp);
+
+    return;
+}
+
+/** Returns the SDK version of the system */
 int getSdkVersion() {
     if (sdkVersion < 0) {
         char sdkString[PROPERTY_VALUE_MAX];

xposed.h

@@ -3,6 +3,8 @@
 
 #include "xposed_shared.h"
 
+#define XPOSED_PROP_FILE "/system/xposed.prop"
+
 #if defined(__LP64__)
   #define XPOSED_LIB_DIR "/system/lib64/"
 #else
@@ -30,6 +32,7 @@ namespace xposed {
     bool handleOptions(int argc, char* const argv[]);
     bool initialize(bool zygote, bool startSystemServer, const char* className, int argc, char* const argv[]);
     void printRomInfo();
+    void parseXposedProp();
     int getSdkVersion();
     bool isDisabled();
     void disableXposed();

xposed_shared.h

@@ -19,7 +19,6 @@
 #define ALOGV LOGV
 #endif
 
-#define XPOSED_VERSION "61"
 #define XPOSED_DIR "/data/data/de.robv.android.xposed.installer/"
 
 namespace xposed {