/*
 * TNG eWallet — Zygisk companion.
 *
 * stable: PLT + ABRT/SIGTRAP swallow + exit_group seccomp@400ms.
 * Promon worker SIGSEGV (libtngdigital_ewallet.so null deref): LR-return skip (cap N).
 * pc==lr 循环 SEGV 也 skip；libc++abi __cxa_guard_acquire → SIGABRT 吞掉。
 */
#include <android/log.h>
#include <errno.h>
#include <linux/audit.h>
#include <linux/filter.h>
#include <linux/seccomp.h>
#include <pthread.h>
#include <signal.h>
#include <stddef.h>
#include <sys/mman.h>
#include <sys/prctl.h>
#include <sys/syscall.h>
#include <sys/sysmacros.h>
#include <ucontext.h>
#include <unistd.h>

#include <atomic>
#include <cstdint>
#include <cstdio>
#include <cstring>

#include "zygisk.hpp"

#define SC_RET_ALLOW        0x7fff0000U
#define SC_RET_ERRNO_EPERM  (0x00050000U | 1U)

#define LOG_TAG "TngExitGuard"
#define LOGI(...) __android_log_print(ANDROID_LOG_INFO, LOG_TAG, __VA_ARGS__)
#define LOGE(...) __android_log_print(ANDROID_LOG_ERROR, LOG_TAG, __VA_ARGS__)

static constexpr const char *kTargetPkg = "my.com.tngdigital.ewallet";
static constexpr const char *kPromonSo = "libtngdigital_ewallet.so";
static bool g_enabled = false;
static zygisk::Api *g_api = nullptr;
static std::atomic<int> g_cxx_plt{0};
static std::atomic<int> g_seccomp_ok{0};
static std::atomic<int> g_stack_chk{0};
static std::atomic<int> g_promon_segv{0};
static std::atomic<uintptr_t> g_promon_start{0};
static std::atomic<uintptr_t> g_promon_end{0};
static std::atomic<pid_t> g_main_tid{0};
static std::atomic<int> g_abrt_swallow{0};
static std::atomic<pid_t> g_abrt_last_tid{0};
static std::atomic<uintptr_t> g_abrt_last_pc{0};
static std::atomic<int> g_abrt_streak{0};
/* 隔离进程 :goacqowmmt 会循环 SEGV；主进程 worker 也狂刷。cap 后 freeze 该线程 */
static constexpr int kMaxPromonSegvSkip = 200;
static constexpr int kMaxAbrtStreak = 3;
static std::atomic<int> g_soft_sig_logged{0};

static void freeze_forever() {
    for (;;) pause();
}

static void refresh_promon_so_range() {
    FILE *fp = fopen("/proc/self/maps", "r");
    if (!fp) return;
    char line[1024];
    uintptr_t start = 0, end = 0;
    while (fgets(line, sizeof(line), fp)) {
        unsigned long s = 0, e = 0;
        char path[512] = {};
        int n = sscanf(line, "%lx-%lx %*s %*s %*s %*s %511[^\n]", &s, &e, path);
        if (n < 3) continue;
        char *p = path;
        while (*p == ' ') ++p;
        if (strstr(p, kPromonSo) == nullptr) continue;
        if (start == 0 || s < start) start = s;
        if (e > end) end = e;
    }
    fclose(fp);
    if (start != 0 && end > start) {
        g_promon_start.store(start);
        g_promon_end.store(end);
    }
}

static bool pc_in_promon_so(uintptr_t pc) {
    uintptr_t start = g_promon_start.load();
    uintptr_t end = g_promon_end.load();
    return start != 0 && pc >= start && pc < end;
}

static void promon_segv_handler(int sig, siginfo_t *info, void *ctx) {
    (void)sig;
    (void)info;
    ucontext_t *uc = reinterpret_cast<ucontext_t *>(ctx);
#if defined(__aarch64__)
    uintptr_t pc = uc->uc_mcontext.pc;
    uintptr_t lr = uc->uc_mcontext.regs[30];
#else
    uintptr_t pc = 0;
    uintptr_t lr = 0;
#endif
    refresh_promon_so_range();
    /* Promon 典型 pc==lr 自旋 null deref；maps 尚未刷新时也按此 skip */
    if (pc != 0 && pc == lr) {
        int n = ++g_promon_segv;
        if (n <= 3 || n % 50 == 0) {
            LOGI("promon pc==lr SIGSEGV tid=%d pc=%lx n=%d — skip to pc+4",
                 (int)gettid(), (unsigned long)pc, n);
        }
        uc->uc_mcontext.pc = pc + 4;
        return;
    }
    if (pc_in_promon_so(pc) || pc_in_promon_so(lr)) {
        int n = ++g_promon_segv;
        uintptr_t target = lr;
        if (target == 0 || target == pc) {
            target = pc + 4;
        }
        if (kMaxPromonSegvSkip <= 0 || n <= kMaxPromonSegvSkip) {
            if (n <= 3 || n % 50 == 0) {
                LOGI("promon SIGSEGV tid=%d pc=%lx lr=%lx n=%d — skip to %lx",
                     (int)gettid(), (unsigned long)pc, (unsigned long)lr, n,
                     (unsigned long)target);
            }
            uc->uc_mcontext.pc = target;
            return;
        }
        LOGI("promon SIGSEGV tid=%d n=%d — cap hit, freeze", (int)gettid(), n);
        freeze_forever();
    }
    /* 1.9.10：Login 后出现 Promon so 外 SEGV → 旧逻辑 re-raise 直接闪退 */
    {
        int n = ++g_promon_segv;
        pid_t tid = gettid();
        if (n <= 5 || n % 50 == 0) {
            LOGI("non-promon SIGSEGV tid=%d pc=%lx lr=%lx n=%d — pc+4",
                 (int)tid, (unsigned long)pc, (unsigned long)lr, n);
        }
        if (n > 200 && tid != g_main_tid.load()) {
            LOGI("non-promon SEGV storm tid=%d — freeze", (int)tid);
            freeze_forever();
        }
        if (pc != 0) {
            uc->uc_mcontext.pc = pc + 4;
            return;
        }
    }
    freeze_forever();
}

/**
 * ABRT/TRAP：一律 pc+4。跳远距 LR 会弄坏主线程 Looper（闪退观感）。
 * 工作线程同 PC 连 abort 超限 → freeze；主线程始终 pc+4。
 */
static void fatal_skip_handler(int sig, siginfo_t *info, void *ctx) {
    (void)info;
    ucontext_t *uc = reinterpret_cast<ucontext_t *>(ctx);
#if defined(__aarch64__)
    uintptr_t pc = uc->uc_mcontext.pc;
    uintptr_t lr = uc->uc_mcontext.regs[30];
    pid_t tid = gettid();

    if (sig == SIGABRT) {
        int streak = 1;
        if (g_abrt_last_tid.load() == tid && g_abrt_last_pc.load() == pc) {
            streak = g_abrt_streak.fetch_add(1) + 1;
        } else {
            g_abrt_last_tid.store(tid);
            g_abrt_last_pc.store(pc);
            g_abrt_streak.store(1);
        }
        if (streak > kMaxAbrtStreak && tid != g_main_tid.load()) {
            LOGI("ABRT streak cap tid=%d pc=%lx n=%d — freeze worker", (int)tid,
                 (unsigned long)pc, streak);
            freeze_forever();
        }
        int n = ++g_abrt_swallow;
        if (n <= 5 || n % 50 == 0) {
            LOGI("ABRT pc+4 tid=%d pc=%lx lr=%lx streak=%d", (int)tid,
                 (unsigned long)pc, (unsigned long)lr, streak);
        }
        uc->uc_mcontext.pc = pc + 4;
        return;
    }

    if (sig == SIGTRAP) {
        int n = ++g_abrt_swallow;
        if (n <= 5 || n % 50 == 0) {
            LOGI("TRAP pc+4 tid=%d pc=%lx", (int)tid, (unsigned long)pc);
        }
        uc->uc_mcontext.pc = pc != 0 ? pc + 4 : lr;
        return;
    }
#endif
    freeze_forever();
}

static void install_fatal_skip_handlers() {
    struct sigaction sa {};
    sa.sa_sigaction = fatal_skip_handler;
    sa.sa_flags = SA_SIGINFO | SA_ONSTACK;
    sigemptyset(&sa.sa_mask);
    sigaction(SIGABRT, &sa, nullptr);
    sigaction(SIGTRAP, &sa, nullptr);
    LOGI("fatal skip handlers (ABRT/TRAP always pc+4)");
}

static void install_promon_segv_handler() {
    refresh_promon_so_range();
    struct sigaction sa {};
    sa.sa_sigaction = promon_segv_handler;
    sa.sa_flags = SA_SIGINFO | SA_ONSTACK;
    sigemptyset(&sa.sa_mask);
    if (sigaction(SIGSEGV, &sa, nullptr) != 0) {
        LOGE("SIGSEGV handler install failed errno=%d", errno);
        return;
    }
    LOGI("promon SIGSEGV handler armed range=%lx-%lx",
         (unsigned long)g_promon_start.load(),
         (unsigned long)g_promon_end.load());
}

static void install_soft_signals() {
    struct sigaction sa {};
    sa.sa_sigaction = fatal_skip_handler;
    sa.sa_flags = SA_SIGINFO | SA_ONSTACK;
    sigemptyset(&sa.sa_mask);
    sigaction(SIGABRT, &sa, nullptr);
    sigaction(SIGTRAP, &sa, nullptr);
    if (g_soft_sig_logged.fetch_add(1) == 0) {
        LOGI("soft signals (ABRT/TRAP always pc+4)");
    }
}

#if defined(__aarch64__)
#define _BPFI(code, jt, jf, k) \
    ((struct sock_filter){(unsigned short)(code), (jt), (jf), (unsigned int)(k)})

static int install_seccomp_exit_group_only() {
    struct sock_filter filter[] = {
        _BPFI(BPF_LD | BPF_W | BPF_ABS, 0, 0, offsetof(struct seccomp_data, arch)),
        _BPFI(BPF_JMP | BPF_JEQ | BPF_K, 1, 0, AUDIT_ARCH_AARCH64),
        _BPFI(BPF_RET | BPF_K, 0, 0, SC_RET_ALLOW),
        _BPFI(BPF_LD | BPF_W | BPF_ABS, 0, 0, offsetof(struct seccomp_data, nr)),
        _BPFI(BPF_JMP | BPF_JEQ | BPF_K, 0, 1, 94),
        _BPFI(BPF_RET | BPF_K, 0, 0, SC_RET_ERRNO_EPERM),
        _BPFI(BPF_RET | BPF_K, 0, 0, SC_RET_ALLOW),
    };
    struct sock_fprog prog = {
        .len = (unsigned short)(sizeof(filter) / sizeof(filter[0])),
        .filter = filter,
    };
    prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
    long rc = syscall(__NR_seccomp, SECCOMP_SET_MODE_FILTER,
                      SECCOMP_FILTER_FLAG_TSYNC, &prog);
    if (rc != 0) {
        rc = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog);
        if (rc != 0) {
            LOGE("seccomp failed errno=%d", errno);
            return -1;
        }
        LOGI("seccomp exit_group via prctl");
    } else {
        LOGI("seccomp exit_group via TSYNC");
    }
    g_seccomp_ok.store(1);
    return 0;
}
#else
static int install_seccomp_exit_group_only() { return -1; }
#endif

using exit_fn = void (*)(int);
using kill_fn = int (*)(pid_t, int);
using tgkill_fn = int (*)(int, int, int);
using raise_fn = int (*)(int);
using pthread_kill_fn = int (*)(pthread_t, int);
using cxa_guard_acquire_fn = int (*)(void *);
using cxa_guard_abort_fn = void (*)();
using dlopen_fn = void *(*)(const char *, int);

static cxa_guard_acquire_fn orig_cxa_guard_acquire = nullptr;
static cxa_guard_abort_fn orig_cxa_guard_abort = nullptr;
static dlopen_fn orig_dlopen = nullptr;

static exit_fn orig_exit = nullptr;
static exit_fn orig__exit = nullptr;
static void (*orig_abort)() = nullptr;
static void (*orig_stack_chk_fail)() = nullptr;
static kill_fn orig_kill = nullptr;
static tgkill_fn orig_tgkill = nullptr;
static raise_fn orig_raise = nullptr;
static pthread_kill_fn orig_pthread_kill = nullptr;

static bool deadly(int sig) {
    return sig == SIGKILL || sig == SIGABRT || sig == SIGTERM ||
           sig == SIGTRAP || sig == SIGILL ||
           sig == 9 || sig == 6 || sig == 5 || sig == 4 || sig == 15;
}

static void hooked_exit(int code) { LOGI("blocked exit(%d)", code); }
static void hooked__exit(int code) { LOGI("blocked _exit(%d)", code); }
static void hooked_abort() {
    LOGI("blocked abort() tid=%d", (int)gettid());
}
static void hooked_stack_chk_fail() {
    int n = ++g_stack_chk;
    LOGI("blocked __stack_chk_fail tid=%d n=%d", (int)gettid(), n);
}
static int hooked_raise(int sig) {
    if (deadly(sig)) {
        LOGI("blocked raise(%d)", sig);
        return 0;
    }
    return orig_raise ? orig_raise(sig) : -1;
}
static int hooked_kill(pid_t pid, int sig) {
    if (deadly(sig)) {
        LOGI("blocked kill(%d,%d)", (int)pid, sig);
        return 0;
    }
    return orig_kill ? orig_kill(pid, sig) : -1;
}
static int hooked_tgkill(int tgid, int tid, int sig) {
    if (deadly(sig)) {
        LOGI("blocked tgkill(%d,%d,%d)", tgid, tid, sig);
        return 0;
    }
    return orig_tgkill ? orig_tgkill(tgid, tid, sig) : -1;
}
static int hooked_pthread_kill(pthread_t thread, int sig) {
    if (deadly(sig)) {
        LOGI("blocked pthread_kill(sig=%d)", sig);
        return 0;
    }
    return orig_pthread_kill ? orig_pthread_kill(thread, sig) : -1;
}

/** 仅打断递归初始化；系统 libc++ 静态 ctor（含 gralloc）必须真实执行。 */
static thread_local void *tl_cxa_guard = nullptr;
static thread_local int tl_cxa_depth = 0;

static int hooked_cxa_guard_acquire(void *guard) {
    if (guard != nullptr && tl_cxa_guard == guard) {
        LOGI("cxa_guard recursive skip tid=%d", (int)gettid());
        return 1;
    }
    if (!orig_cxa_guard_acquire) {
        return 1;
    }
    void *prev = tl_cxa_guard;
    tl_cxa_guard = guard;
    ++tl_cxa_depth;
    int r = orig_cxa_guard_acquire(guard);
    --tl_cxa_depth;
    tl_cxa_guard = prev;
    return r;
}
static void hooked_cxa_guard_abort() {
    LOGI("blocked __cxa_guard_abort tid=%d depth=%d", (int)gettid(), tl_cxa_depth);
}

static void *hooked_dlopen(const char *name, int flags) {
    void *handle = orig_dlopen ? orig_dlopen(name, flags) : nullptr;
    if (handle != nullptr || name == nullptr) {
        return handle;
    }
    // Compose/HWUI 依赖 libandroid + gralloc mapper；sphal 失败时尝试绝对路径兜底
    if (strstr(name, "libandroid.so") != nullptr
            || strstr(name, "mapper.pixel") != nullptr
            || strstr(name, "android.hardware.graphics.mapper") != nullptr) {
        static const char *kFallbacks[] = {
            "/system/lib64/libandroid.so",
            "/system/lib/libandroid.so",
            "/vendor/lib64/hw/mapper.pixel.so",
            "/vendor/lib/hw/mapper.pixel.so",
            "libandroid.so",
            "mapper.pixel.so",
        };
        for (const char *path : kFallbacks) {
            handle = orig_dlopen ? orig_dlopen(path, flags) : nullptr;
            if (handle != nullptr) {
                LOGI("dlopen fallback %s -> %p (from %s)", path, handle, name);
                return handle;
            }
        }
        LOGI("dlopen fallback failed name=%s tid=%d", name, (int)gettid());
    }
    return handle;
}

static bool find_lib_match(const char *suffix, const char *contains,
                           dev_t *dev, ino_t *ino) {
    FILE *fp = fopen("/proc/self/maps", "r");
    if (!fp) return false;
    char line[1024];
    bool ok = false;
    while (fgets(line, sizeof(line), fp)) {
        uintptr_t start = 0, end = 0;
        char perms[8] = {};
        unsigned long long offset = 0;
        char deststr[32] = {};
        unsigned long inode = 0;
        char path[512] = {};
        int n = sscanf(line, "%lx-%lx %7s %llx %31s %lu %511[^\n]",
                       &start, &end, perms, &offset, &deststr, &inode, path);
        if (n < 7 || inode == 0) continue;
        char *p = path;
        while (*p == ' ') ++p;
        bool match = false;
        if (suffix != nullptr) {
            size_t plen = strlen(p);
            size_t slen = strlen(suffix);
            match = plen >= slen && strcmp(p + plen - slen, suffix) == 0;
        } else if (contains != nullptr) {
            match = strstr(p, contains) != nullptr;
        }
        if (!match) continue;
        unsigned maj = 0, min = 0;
        if (sscanf(deststr, "%x:%x", &maj, &min) != 2) continue;
        *dev = makedev(maj, min);
        *ino = inode;
        ok = true;
        break;
    }
    fclose(fp);
    return ok;
}

static bool find_lib_by_suffix(const char *suffix, dev_t *dev, ino_t *ino) {
    return find_lib_match(suffix, nullptr, dev, ino);
}

static bool find_lib_contains(const char *needle, dev_t *dev, ino_t *ino) {
    return find_lib_match(nullptr, needle, dev, ino);
}

static bool find_libc(dev_t *dev, ino_t *ino) {
    return find_lib_by_suffix("libc.so", dev, ino);
}

static void register_plt(zygisk::Api *api, dev_t dev, ino_t ino,
                         const char *sym, void *hook, void **orig) {
    if (!api || dev == 0 || ino == 0) return;
    api->pltHookRegister(dev, ino, sym, hook, orig);
}

static void install_plt(zygisk::Api *api) {
    if (!api) return;
    dev_t dev = 0;
    ino_t ino = 0;
    if (find_libc(&dev, &ino)) {
        register_plt(api, dev, ino, "exit", (void *)hooked_exit, (void **)&orig_exit);
        register_plt(api, dev, ino, "_exit", (void *)hooked__exit, (void **)&orig__exit);
        register_plt(api, dev, ino, "abort", (void *)hooked_abort, (void **)&orig_abort);
        register_plt(api, dev, ino, "__stack_chk_fail",
                     (void *)hooked_stack_chk_fail, (void **)&orig_stack_chk_fail);
        register_plt(api, dev, ino, "raise", (void *)hooked_raise, (void **)&orig_raise);
        register_plt(api, dev, ino, "kill", (void *)hooked_kill, (void **)&orig_kill);
        register_plt(api, dev, ino, "tgkill", (void *)hooked_tgkill, (void **)&orig_tgkill);
        register_plt(api, dev, ino, "pthread_kill",
                     (void *)hooked_pthread_kill, (void **)&orig_pthread_kill);
        register_plt(api, dev, ino, "dlopen", (void *)hooked_dlopen, (void **)&orig_dlopen);
    }
    bool ok = api->pltHookCommit();
    LOGI("PLT commit=%d", ok ? 1 : 0);
}

static void try_install_cxx_guard_plt() {
    if (g_cxx_plt.load() || !g_api) return;
    dev_t dev = 0;
    ino_t ino = 0;
    bool any = false;
    // libc++：必须走 orig acquire（否则 gralloc 静态初始化被跳过 → mapper missing 黑屏）。
    // 仅在同 guard 递归时 return 1；abort 仍拦截。
    if (find_lib_by_suffix("libc++.so", &dev, &ino)
            || find_lib_by_suffix("libc++_shared.so", &dev, &ino)) {
        register_plt(g_api, dev, ino, "__cxa_guard_acquire",
                     (void *)hooked_cxa_guard_acquire, (void **)&orig_cxa_guard_acquire);
        register_plt(g_api, dev, ino, "__cxa_guard_abort",
                     (void *)hooked_cxa_guard_abort, (void **)&orig_cxa_guard_abort);
        any = true;
        LOGI("cxx guard target libc++");
    }
    if (find_lib_by_suffix("libtngdigital_ewallet.so", &dev, &ino)) {
        register_plt(g_api, dev, ino, "__cxa_guard_acquire",
                     (void *)hooked_cxa_guard_acquire, (void **)&orig_cxa_guard_acquire);
        register_plt(g_api, dev, ino, "__cxa_guard_abort",
                     (void *)hooked_cxa_guard_abort, (void **)&orig_cxa_guard_abort);
        any = true;
        LOGI("cxx guard target libtngdigital_ewallet");
    }
    if (!any) return;
    if (g_api->pltHookCommit()) {
        g_cxx_plt.store(1);
        LOGI("PLT cxx guards committed (orig acquire + recursive skip)");
    }
}

static void *phase_thread(void *) {
    install_promon_segv_handler();
    usleep(400 * 1000);
    install_seccomp_exit_group_only();
    LOGI("seccomp armed @400ms ok=%d", g_seccomp_ok.load());
    for (int i = 0; i < 40; i++) {
        usleep(1000 * 1000);
        install_soft_signals();
        install_promon_segv_handler();
        try_install_cxx_guard_plt();
        if (i % 5 == 0) refresh_promon_so_range();
    }
    LOGI("phase done seccomp=%d stack_chk=%d promon_segv=%d",
         g_seccomp_ok.load(), g_stack_chk.load(), g_promon_segv.load());
    return nullptr;
}

static void install_all(zygisk::Api *api) {
    g_api = api;
    g_main_tid.store(gettid());
    LOGI("install pid=%d main_tid=%d (PLT+cxx-guard+ABRT-pc+4+SEGV-skip+exit_group@400ms)",
         getpid(), (int)g_main_tid.load());
    install_fatal_skip_handlers();
    install_soft_signals();
    install_plt(api);
    pthread_t th;
    if (pthread_create(&th, nullptr, phase_thread, nullptr) == 0) {
        pthread_detach(th);
    }
    LOGI("ready");
}

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

    void preAppSpecialize(zygisk::AppSpecializeArgs *args) override {
        const char *nice = nullptr;
        if (args->nice_name) {
            nice = env->GetStringUTFChars(args->nice_name, nullptr);
        }
        bool match = nice && (
                std::strncmp(nice, kTargetPkg, std::strlen(kTargetPkg)) == 0);
        if (nice) env->ReleaseStringUTFChars(args->nice_name, nice);
        g_enabled = match;
        if (!match) {
            api->setOption(zygisk::Option::DLCLOSE_MODULE_LIBRARY);
            return;
        }
        LOGI("preAppSpecialize matched");
    }

    void postAppSpecialize(const zygisk::AppSpecializeArgs *args) override {
        (void)args;
        if (!g_enabled) return;
        install_all(api);
    }

private:
    zygisk::Api *api = nullptr;
    JNIEnv *env = nullptr;
};

REGISTER_ZYGISK_MODULE(TngExitGuardModule)