Add flag for unloaded Zygisk modules

native/jni/core/module.cpp

@@ -715,6 +715,7 @@ static void collect_modules(bool open_zygisk) {
 #else
 #error Unsupported ABI
 #endif
+                unlinkat(modfd, "zygisk/unloaded", 0);
             }
         } else {
             // Ignore zygisk modules when zygisk is not enabled

native/jni/utils/misc.hpp

@@ -4,6 +4,7 @@
 #include <string>
 #include <functional>
 #include <string_view>
+#include <bitset>
 
 #define UID_ROOT   0
 #define UID_SHELL  2000
@@ -79,6 +80,24 @@ public:
     bool operator!=(const stateless_allocator&) { return false; }
 };
 
+class dynamic_bitset {
+private:
+    using long_bits = std::bitset<sizeof(unsigned long)>;
+    std::vector<long_bits> bits;
+public:
+    constexpr static int slot_size = sizeof(unsigned long);
+    long_bits::reference operator[] (size_t pos) {
+        size_t slot = pos / slot_size;
+        size_t index = pos % slot_size;
+        if (bits.size() <= slot) {
+            bits.resize(slot + 1);
+        }
+        return bits[slot][index];
+    }
+    size_t slots() const { return bits.size(); }
+    unsigned long to_ulong(size_t slot) const { return bits[slot].to_ulong(); }
+};
+
 int parse_int(std::string_view s);
 
 using thread_entry = void *(*)(void *);

native/jni/zygisk/entry.cpp

@@ -167,8 +167,7 @@ static int zygisk_log(int prio, const char *fmt, va_list ap) {
     return ret;
 }
 
-std::vector<int> remote_get_info(int uid, const char *process, uint32_t *flags) {
+int remote_get_info(int uid, const char *process, uint32_t *flags, vector<int> &fds) {
-    vector<int> fds;
     if (int fd = connect_daemon(); fd >= 0) {
         write_int(fd, ZYGISK_REQUEST);
         write_int(fd, ZYGISK_GET_INFO);
@@ -179,9 +178,9 @@ std::vector<int> remote_get_info(int uid, const char *process, uint32_t *flags)
         if ((*flags & UNMOUNT_MASK) != UNMOUNT_MASK) {
             fds = recv_fds(fd);
         }
-        close(fd);
+        return fd;
     }
-    return fds;
+    return -1;
 }
 
 // The following code runs in magiskd
@@ -358,6 +357,27 @@ static void get_process_info(int client, const sock_cred *cred) {
         vector<int> fds = get_module_fds(str_ends(buf, "64"));
         send_fds(client, fds.data(), fds.size());
     }
+
+    // The following will only happen for system_server
+    int slots = read_int(client);
+    int id = 0;
+    for (int i = 0; i < slots; ++i) {
+        unsigned long l = 0;
+        xxread(client, &l, sizeof(l));
+        bitset<sizeof(unsigned long)> bits(l);
+        for (int j = 0; id < module_list->size(); ++j, ++id) {
+            if (!bits[j]) {
+                // Either not a zygisk module, or incompatible
+                char buf[4096];
+                snprintf(buf, sizeof(buf), MODULEROOT "/%s/zygisk",
+                    module_list->operator[](id).name.data());
+                if (int dirfd = open(buf, O_RDONLY | O_CLOEXEC); dirfd >= 0) {
+                    close(xopenat(dirfd, "unloaded", O_CREAT | O_RDONLY, 0644));
+                    close(dirfd);
+                }
+            }
+        }
+    }
 }
 
 static void send_log_pipe(int fd) {

native/jni/zygisk/hook.cpp

@@ -450,14 +450,16 @@ void HookContext::nativeSpecializeAppProcess_pre() {
         ZLOGV("pre  specialize [%s]\n", process);
     }
 
-    auto module_fds = remote_get_info(args->uid, process, &flags);
+    vector<int> module_fds;
+    int fd = remote_get_info(args->uid, process, &flags, module_fds);
     if ((flags & UNMOUNT_MASK) == UNMOUNT_MASK) {
-        // TODO: Handle MOUNT_EXTERNAL_NONE on older platforms
         ZLOGI("[%s] is on the denylist\n", process);
         state[DO_UNMOUNT] = true;
-    } else {
+    } else if (fd >= 0) {
         run_modules_pre(module_fds);
+        write_int(fd, 0);
     }
+    close(fd);
 
     close_fds();
     android_logging();
@@ -486,7 +488,29 @@ void HookContext::nativeForkSystemServer_pre() {
     state[SERVER_SPECIALIZE] = true;
     if (pid == 0) {
         ZLOGV("pre  forkSystemServer\n");
-        run_modules_pre(remote_get_info(1000, "system_server", &flags));
+        vector<int> module_fds;
+        int fd = remote_get_info(1000, "system_server", &flags, module_fds);
+        if (fd >= 0) {
+            if (module_fds.empty()) {
+                write_int(fd, 0);
+            } else {
+                run_modules_pre(module_fds);
+
+                // Send the bitset of module status back to magiskd from system_server
+                dynamic_bitset bits;
+                // Pre-allocate enough bits
+                bits[module_fds.size() - 1] = false;
+                for (const auto &m : modules) {
+                    bits[m.getId()] = true;
+                }
+                write_int(fd, bits.slots());
+                for (int i = 0; i < bits.slots(); ++i) {
+                    unsigned long l = bits.to_ulong(i);
+                    xwrite(fd, &l, sizeof(l));
+                }
+            }
+            close(fd);
+        }
         close_fds();
         android_logging();
     }

native/jni/zygisk/module.hpp

@@ -119,6 +119,7 @@ struct ZygiskModule {
     void setOption(zygisk::Option opt);
     static uint32_t getFlags();
     void doUnload() const { if (unload) dlclose(handle); }
+    int getId() const { return id; }
 
     ZygiskModule(int id, void *handle, void *entry);
 

native/jni/zygisk/zygisk.hpp

@@ -41,5 +41,5 @@ extern void *self_handle;
 
 void unload_first_stage();
 void hook_functions();
-std::vector<int> remote_get_info(int uid, const char *process, uint32_t *flags);
+int remote_get_info(int uid, const char *process, uint32_t *flags, std::vector<int> &fds);
 int remote_request_unmount();