safetynet-fix/zygisk/module/jni/example.cpp

#include <cstdlib>
#include <unistd.h>
#include <fcntl.h>
#include <android/log.h>

#include "zygisk.hpp"

using zygisk::Api;
using zygisk::AppSpecializeArgs;
using zygisk::ServerSpecializeArgs;

#define LOGD(...) __android_log_print(ANDROID_LOG_DEBUG, "Magisk", __VA_ARGS__)

class MyModule : public zygisk::ModuleBase {
public:
    void onLoad(Api *api, JNIEnv *env) override {
        this->api = api;
        this->env = env;
    }

    void preAppSpecialize(AppSpecializeArgs *args) override {
        // Use JNI to fetch our process name
        const char *process = env->GetStringUTFChars(args->nice_name, nullptr);
        preSpecialize(process);
        env->ReleaseStringUTFChars(args->nice_name, process);
    }

    void preServerSpecialize(ServerSpecializeArgs *args) override {
        preSpecialize("system_server");
    }

private:
    Api *api;
    JNIEnv *env;

    void preSpecialize(const char *process) {
        // Demonstrate connecting to to companion process
        // We ask the companion for a random number
        int r = 0;
        int fd = api->connectCompanion();
        read(fd, &r, sizeof(r));
        close(fd);
        LOGD("example: process=[%s], r=[%u]\n", process, r);
    }

};

static void companion_handler(int i) {
    int fd = open("/dev/urandom", O_RDONLY);
    int r;
    read(fd, &r, sizeof(r));
    close(fd);
    LOGD("example: companion r=[%u]\n", r);
    write(i, &r, sizeof(r));
}

REGISTER_ZYGISK_MODULE(MyModule)
REGISTER_ZYGISK_COMPANION(companion_handler)