Code reorganization

native/src/core/zygisk/entry.cpp

@@ -1,35 +1,116 @@
-#include <libgen.h>
-#include <dlfcn.h>
-#include <sys/prctl.h>
 #include <sys/mount.h>
-#include <android/log.h>
 #include <android/dlext.h>
+#include <dlfcn.h>
 
-#include <base.hpp>
 #include <consts.hpp>
+#include <base.hpp>
+#include <core.hpp>
+#include <selinux.hpp>
 
 #include "zygisk.hpp"
-#include "module.hpp"
 
 using namespace std;
 
 string native_bridge = "0";
 
-static bool is_compatible_with(uint32_t) {
-    zygisk_logging();
-    hook_entry();
-    ZLOGD("load success\n");
-    return false;
+static void zygiskd(int socket) {
+    if (getuid() != 0 || fcntl(socket, F_GETFD) < 0)
+        exit(-1);
+
+    init_thread_pool();
+
+#if defined(__LP64__)
+    set_nice_name("zygiskd64");
+    LOGI("* Launching zygiskd64\n");
+#else
+    set_nice_name("zygiskd32");
+    LOGI("* Launching zygiskd32\n");
+#endif
+
+    // Load modules
+    using comp_entry = void(*)(int);
+    vector<comp_entry> modules;
+    {
+        auto module_fds = recv_fds(socket);
+        for (int fd : module_fds) {
+            comp_entry entry = nullptr;
+            struct stat s{};
+            if (fstat(fd, &s) == 0 && S_ISREG(s.st_mode)) {
+                android_dlextinfo info {
+                    .flags = ANDROID_DLEXT_USE_LIBRARY_FD,
+                    .library_fd = fd,
+                };
+                if (void *h = android_dlopen_ext("/jit-cache", RTLD_LAZY, &info)) {
+                    *(void **) &entry = dlsym(h, "zygisk_companion_entry");
+                } else {
+                    LOGW("Failed to dlopen zygisk module: %s\n", dlerror());
+                }
+            }
+            modules.push_back(entry);
+            close(fd);
+        }
+    }
+
+    // ack
+    write_int(socket, 0);
+
+    // Start accepting requests
+    pollfd pfd = { socket, POLLIN, 0 };
+    for (;;) {
+        poll(&pfd, 1, -1);
+        if (pfd.revents && !(pfd.revents & POLLIN)) {
+            // Something bad happened in magiskd, terminate zygiskd
+            exit(0);
+        }
+        int client = recv_fd(socket);
+        if (client < 0) {
+            // Something bad happened in magiskd, terminate zygiskd
+            exit(0);
+        }
+        int module_id = read_int(client);
+        if (module_id >= 0 && module_id < modules.size() && modules[module_id]) {
+            exec_task([=, entry = modules[module_id]] {
+                struct stat s1;
+                fstat(client, &s1);
+                entry(client);
+                // Only close client if it is the same file so we don't
+                // accidentally close a re-used file descriptor.
+                // This check is required because the module companion
+                // handler could've closed the file descriptor already.
+                if (struct stat s2; fstat(client, &s2) == 0) {
+                    if (s1.st_dev == s2.st_dev && s1.st_ino == s2.st_ino) {
+                        close(client);
+                    }
+                }
+            });
+        } else {
+            close(client);
+        }
+    }
 }
 
+// Entrypoint where we need to re-exec ourselves
+// This should only ever be called internally
+int zygisk_main(int argc, char *argv[]) {
+    android_logging();
+    if (argc == 3 && argv[1] == "companion"sv) {
+        zygiskd(parse_int(argv[2]));
+    }
+    return 0;
+}
+
+// Entrypoint of code injection
 extern "C" [[maybe_unused]] NativeBridgeCallbacks NativeBridgeItf {
     .version = 2,
     .padding = {},
-    .isCompatibleWith = &is_compatible_with,
+    .isCompatibleWith = [](auto) {
+        zygisk_logging();
+        hook_entry();
+        ZLOGD("load success\n");
+        return false;
+    },
 };
 
-// The following code runs in magiskd
-
 void restore_zygisk_prop() {
     string native_bridge_orig = "0";
     if (native_bridge.length() > strlen(ZYGISKLDR)) {