Check packages.xml inode to trigger app rescan

This commit is contained in:
topjohnwu 2022-02-14 02:57:33 -08:00
parent 5a39f7cdde
commit 4c80808997
2 changed files with 22 additions and 33 deletions

View File

@ -14,24 +14,9 @@
using namespace std;
#define FIRST_APP_UID 10000
struct app_id_bitset : public dynamic_bitset_impl {
slot_bits::reference operator[] (size_t pos) {
return pos < FIRST_APP_UID ? get(0) : get(pos - FIRST_APP_UID);
}
bool operator[] (size_t pos) const {
return pos < FIRST_APP_UID || get(pos - FIRST_APP_UID);
}
};
// For the following data structures:
// If package name == ISOLATED_MAGIC, or app ID == -1, it means isolated service
// List of all discovered app IDs
static unique_ptr<app_id_bitset> app_ids_seen_;
#define app_ids_seen (*app_ids_seen_)
// Package name -> list of process names
static unique_ptr<map<string, set<string, StringCmp>, StringCmp>> pkg_to_procs_;
#define pkg_to_procs (*pkg_to_procs_)
@ -47,9 +32,24 @@ atomic<bool> denylist_enforced = false;
#define do_kill (zygisk_enabled && denylist_enforced)
static unsigned long long pkg_xml_ino = 0;
static void rescan_apps() {
{
struct stat st{};
stat("/data/system/packages.xml", &st);
if (pkg_xml_ino == st.st_ino) {
// Packages has not changed, do not rescan
return;
}
pkg_xml_ino = st.st_ino;
}
LOGD("denylist: rescanning apps\n");
app_id_to_pkgs.clear();
cached_manager_app_id = -1;
auto data_dir = xopen_dir(APP_DATA_DIR);
if (!data_dir)
return;
@ -67,7 +67,6 @@ static void rescan_apps() {
// This app ID has been handled
continue;
}
app_ids_seen[app_id] = true;
if (auto it = pkg_to_procs.find(entry->d_name); it != pkg_to_procs.end()) {
app_id_to_pkgs[app_id].insert(it->first);
}
@ -99,7 +98,6 @@ static void update_pkg_uid(const string &pkg, bool remove) {
}
} else {
app_id_to_pkgs[app_id].insert(pkg);
app_ids_seen[app_id] = true;
}
break;
}
@ -201,13 +199,12 @@ static auto add_hide_set(const char *pkg, const char *proc) {
}
static void clear_data() {
app_ids_seen_.reset(nullptr);
pkg_to_procs_.reset(nullptr);
app_id_to_pkgs_.reset(nullptr);
}
static bool ensure_data() {
if (app_ids_seen_)
if (pkg_to_procs_)
return true;
LOGI("denylist: initializing internal data structures\n");
@ -219,7 +216,6 @@ static bool ensure_data() {
});
db_err_cmd(err, goto error)
default_new(app_ids_seen_);
default_new(app_id_to_pkgs_);
rescan_apps();
@ -404,6 +400,8 @@ bool is_deny_target(int uid, string_view process) {
if (!ensure_data())
return false;
rescan_apps();
int app_id = to_app_id(uid);
if (app_id >= 90000) {
if (auto it = pkg_to_procs.find(ISOLATED_MAGIC); it != pkg_to_procs.end()) {
@ -414,12 +412,6 @@ bool is_deny_target(int uid, string_view process) {
}
return false;
} else {
if (!app_ids_seen[app_id]) {
// Found new app ID
cached_manager_app_id = -1;
rescan_apps();
}
auto it = app_id_to_pkgs.find(app_id);
if (it == app_id_to_pkgs.end())
return false;

View File

@ -330,25 +330,22 @@ static void get_process_info(int client, const sock_cred *cred) {
// This function is called on every single zygote process specialization,
// so performance is critical. get_manager_app_id() is expensive as it goes
// through a SQLite query and potentially multiple filesystem stats, so we
// really want to cache the app ID value. inotify will invalidate the app ID
// cache for us.
// really want to cache its app ID value.
if (is_deny_target(uid, process)) {
flags |= PROCESS_ON_DENYLIST;
}
int manager_app_id = cached_manager_app_id;
if (manager_app_id < 0) {
manager_app_id = get_manager_app_id();
cached_manager_app_id = manager_app_id;
}
if (to_app_id(uid) == manager_app_id) {
flags |= PROCESS_IS_MAGISK_APP;
}
if (denylist_enforced) {
flags |= DENYLIST_ENFORCING;
}
if (is_deny_target(uid, process)) {
flags |= PROCESS_ON_DENYLIST;
}
if (uid_granted_root(uid)) {
flags |= PROCESS_GRANTED_ROOT;
}