installd守护进程

android11-release
PackageManagerServie 服务负责应用的安装、卸载等相关工作，而真正干活的还是 installd。

installd 启动

Android系统启动查看 init 进程system/core/init/init.cpp中SecondStageMain，最终在 LoadBootScripts 解析 rc 文件，其中解析 installd.rc，调用到installd.cpp主函数。InstalldNativeService::start()将该服务发布到 native 层的 ServiceManager 中。

frameworks/native/cmds/installd/installd.rc

service installd /system/bin/installdclass main

frameworks/native/cmds/installd/installd.cpp

namespace android {
namespace installd {
//... ...
static int installd_main(const int argc ATTRIBUTE_UNUSED, char *argv[]) {//... ...if ((ret = InstalldNativeService::start()) != android::OK) {SLOGE("Unable to start InstalldNativeService: %d", ret);exit(1);}//... ...return 0;
}}  // namespace installd
}  // namespace androidint main(const int argc, char *argv[]) {return android::installd::installd_main(argc, argv);
}

InstalldNativeService

frameworks/native/cmds/installd/InstalldNativeService.h
frameworks/native/cmds/installd/InstalldNativeService.cpp

InstalldNativeService 继承 BinderService（Binder通信，之前socket），BinderService::publish() 将"installd"服务添加到ServiceManager中
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status_t InstalldNativeService::start() {IPCThreadState::self()->disableBackgroundScheduling(true);status_t ret = BinderService<InstalldNativeService>::publish();if (ret != android::OK) {return ret;}sp<ProcessState> ps(ProcessState::self());ps->startThreadPool();ps->giveThreadPoolName();sAppDataIsolationEnabled = android::base::GetBoolProperty(kAppDataIsolationEnabledProperty, true);return android::OK;
}

frameworks/native/libs/binder/include/binder/BinderService.h

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Installer.java 连接 “installd” 服务

SystemServer 中 startBootstrapServices 启动 Installer 连接 “installd” 服务
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installd_main 其他函数

回到 installd 查看其他函数

initialize_globals()

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frameworks/native/cmds/installd/globals.h
frameworks/native/cmds/installd/globals.cpp

获取相关目录：/data/、/system、/data/app/、/data/app-private/、/data/app-ephemeral/、/data/app-lib/、/data/app-lib/、/mnt/asec、/data/media/、/mnt/expand/、/data/misc/profiles、/data/app-staging/、/system/app/、/system/app-private/、/vendor/app/、/oem/app/

bool init_globals_from_data_and_root(const char* data, const char* root) {// Get the android data directory.android_data_dir = ensure_trailing_slash(data);// Get the android root directory.android_root_dir = ensure_trailing_slash(root);// Get the android app directory.android_app_dir = android_data_dir + APP_SUBDIR;// Get the android protected app directory.android_app_private_dir = android_data_dir + PRIVATE_APP_SUBDIR;// Get the android ephemeral app directory.android_app_ephemeral_dir = android_data_dir + EPHEMERAL_APP_SUBDIR;// Get the android app native library directory.android_app_lib_dir = android_data_dir + APP_LIB_SUBDIR;// Get the sd-card ASEC mount point.android_asec_dir = ensure_trailing_slash(getenv(ASEC_MOUNTPOINT_ENV_NAME));// Get the android media directory.android_media_dir = android_data_dir + MEDIA_SUBDIR;// Get the android external app directory.android_mnt_expand_dir = "/mnt/expand/";// Get the android profiles directory.android_profiles_dir = android_data_dir + PROFILES_SUBDIR;// Get the android session staging directory.android_staging_dir = android_data_dir + STAGING_SUBDIR;// Take note of the system and vendor directories.android_system_dirs.clear();android_system_dirs.push_back(android_root_dir + APP_SUBDIR);android_system_dirs.push_back(android_root_dir + PRIV_APP_SUBDIR);android_system_dirs.push_back("/vendor/app/");android_system_dirs.push_back("/oem/app/");return true;
}

initialize_directories()

读取当前文件系统版本
处理升级路径

static int initialize_directories() {int res = -1;// Read current filesystem layout version to handle upgrade pathschar version_path[PATH_MAX];snprintf(version_path, PATH_MAX, "%smisc/installd/layout_version", android_data_dir.c_str());int oldVersion;if (fs_read_atomic_int(version_path, &oldVersion) == -1) {oldVersion = 0;}int version = oldVersion;if (version < 2) {SLOGD("Assuming that device has multi-user storage layout; upgrade no longer supported");version = 2;}if (ensure_config_user_dirs(0) == -1) {SLOGE("Failed to setup misc for user 0");goto fail;}if (version == 2) {SLOGD("Upgrading to /data/misc/user directories");char misc_dir[PATH_MAX];snprintf(misc_dir, PATH_MAX, "%smisc", android_data_dir.c_str());char keychain_added_dir[PATH_MAX];snprintf(keychain_added_dir, PATH_MAX, "%s/keychain/cacerts-added", misc_dir);char keychain_removed_dir[PATH_MAX];snprintf(keychain_removed_dir, PATH_MAX, "%s/keychain/cacerts-removed", misc_dir);DIR *dir;struct dirent *dirent;dir = opendir("/data/user");if (dir != nullptr) {while ((dirent = readdir(dir))) {const char *name = dirent->d_name;// skip "." and ".."if (name[0] == '.') {if (name[1] == 0) continue;if ((name[1] == '.') && (name[2] == 0)) continue;}uint32_t user_id = std::stoi(name);// /data/misc/user/<user_id>if (ensure_config_user_dirs(user_id) == -1) {goto fail;}char misc_added_dir[PATH_MAX];snprintf(misc_added_dir, PATH_MAX, "%s/user/%s/cacerts-added", misc_dir, name);char misc_removed_dir[PATH_MAX];snprintf(misc_removed_dir, PATH_MAX, "%s/user/%s/cacerts-removed", misc_dir, name);uid_t uid = multiuser_get_uid(user_id, AID_SYSTEM);gid_t gid = uid;if (access(keychain_added_dir, F_OK) == 0) {if (copy_dir_files(keychain_added_dir, misc_added_dir, uid, gid) != 0) {SLOGE("Some files failed to copy");}}if (access(keychain_removed_dir, F_OK) == 0) {if (copy_dir_files(keychain_removed_dir, misc_removed_dir, uid, gid) != 0) {SLOGE("Some files failed to copy");}}}closedir(dir);if (access(keychain_added_dir, F_OK) == 0) {delete_dir_contents(keychain_added_dir, 1, nullptr);}if (access(keychain_removed_dir, F_OK) == 0) {delete_dir_contents(keychain_removed_dir, 1, nullptr);}}version = 3;}// Persist layout version if changedif (version != oldVersion) {if (fs_write_atomic_int(version_path, version) == -1) {SLOGE("Failed to save version to %s: %s", version_path, strerror(errno));goto fail;}}// Success!res = 0;fail:return res;
}