snapuserd: Add a no-socket mode.
In first-stage init, during the selinux transition, no socket is needed.
It's even advantageous not to create one, since it greatly reduces the
amount of avc audits. This patch allows starting snapuserd with a preset
list of socket commands that it can run on startup.
Bug: 173476209
Test: manual test
Change-Id: I758d99097372e4dffb252e2836fd859b7fed162a
diff --git a/fs_mgr/libsnapshot/snapuserd_daemon.cpp b/fs_mgr/libsnapshot/snapuserd_daemon.cpp
index f068547..7fa01b7 100644
--- a/fs_mgr/libsnapshot/snapuserd_daemon.cpp
+++ b/fs_mgr/libsnapshot/snapuserd_daemon.cpp
@@ -17,21 +17,42 @@
#include "snapuserd_daemon.h"
#include <android-base/logging.h>
+#include <android-base/strings.h>
#include <gflags/gflags.h>
#include <libsnapshot/snapuserd_client.h>
#include "snapuserd_server.h"
DEFINE_string(socket, android::snapshot::kSnapuserdSocket, "Named socket or socket path.");
+DEFINE_bool(no_socket, false,
+ "If true, no socket is used. Each additional argument is an INIT message.");
namespace android {
namespace snapshot {
-void Daemon::StartServer() {
- if (!server_.Start(FLAGS_socket)) {
- LOG(ERROR) << "Snapuserd daemon failed to start...";
- exit(EXIT_FAILURE);
+bool Daemon::StartServer(int argc, char** argv) {
+ int arg_start = gflags::ParseCommandLineFlags(&argc, &argv, true);
+
+ if (!FLAGS_no_socket) {
+ return server_.Start(FLAGS_socket);
}
+
+ for (int i = arg_start; i < argc; i++) {
+ auto parts = android::base::Split(argv[i], ",");
+ if (parts.size() != 3) {
+ LOG(ERROR) << "Malformed message, expected three sub-arguments.";
+ return false;
+ }
+ auto handler = server_.AddHandler(parts[0], parts[1], parts[2]);
+ if (!handler || !server_.StartHandler(handler)) {
+ return false;
+ }
+ }
+
+ // Skip the accept() call to avoid spurious log spam. The server will still
+ // run until all handlers have completed.
+ server_.SetTerminating();
+ return true;
}
void Daemon::MaskAllSignalsExceptIntAndTerm() {
@@ -96,14 +117,15 @@
} // namespace snapshot
} // namespace android
-int main([[maybe_unused]] int argc, char** argv) {
+int main(int argc, char** argv) {
android::base::InitLogging(argv, &android::base::KernelLogger);
android::snapshot::Daemon& daemon = android::snapshot::Daemon::Instance();
- gflags::ParseCommandLineFlags(&argc, &argv, false);
-
- daemon.StartServer();
+ if (!daemon.StartServer(argc, argv)) {
+ LOG(ERROR) << "Snapuserd daemon failed to start.";
+ exit(EXIT_FAILURE);
+ }
daemon.Run();
return 0;
diff --git a/fs_mgr/libsnapshot/snapuserd_daemon.h b/fs_mgr/libsnapshot/snapuserd_daemon.h
index ab91088..f8afac5 100644
--- a/fs_mgr/libsnapshot/snapuserd_daemon.h
+++ b/fs_mgr/libsnapshot/snapuserd_daemon.h
@@ -16,6 +16,9 @@
#include <poll.h>
+#include <string>
+#include <vector>
+
#include "snapuserd_server.h"
namespace android {
@@ -32,7 +35,7 @@
return instance;
}
- void StartServer();
+ bool StartServer(int argc, char** argv);
void Run();
void Interrupt();
diff --git a/fs_mgr/libsnapshot/snapuserd_server.cpp b/fs_mgr/libsnapshot/snapuserd_server.cpp
index 9f460c1..8351155 100644
--- a/fs_mgr/libsnapshot/snapuserd_server.cpp
+++ b/fs_mgr/libsnapshot/snapuserd_server.cpp
@@ -116,7 +116,7 @@
switch (op) {
case DaemonOperations::INIT: {
// Message format:
- // init,<misc_name>,<cow_device_path>,<control_device>
+ // init,<misc_name>,<cow_device_path>,<backing_device>
//
// Reads the metadata and send the number of sectors
if (out.size() != 4) {
@@ -124,24 +124,12 @@
return Sendmsg(fd, "fail");
}
- auto snapuserd = std::make_unique<Snapuserd>(out[1], out[2], out[3]);
- if (!snapuserd->InitCowDevice()) {
- LOG(ERROR) << "Failed to initialize Snapuserd";
+ auto handler = AddHandler(out[1], out[2], out[3]);
+ if (!handler) {
return Sendmsg(fd, "fail");
}
- std::string retval = "success," + std::to_string(snapuserd->GetNumSectors());
-
- auto handler = std::make_unique<DmUserHandler>(std::move(snapuserd));
- {
- std::lock_guard<std::mutex> lock(lock_);
- if (FindHandler(&lock, out[1]) != dm_users_.end()) {
- LOG(ERROR) << "Handler already exists: " << out[1];
- return Sendmsg(fd, "fail");
- }
- dm_users_.push_back(std::move(handler));
- }
-
+ auto retval = "success," + std::to_string(handler->snapuserd()->GetNumSectors());
return Sendmsg(fd, retval);
}
case DaemonOperations::START: {
@@ -164,11 +152,9 @@
LOG(ERROR) << "Tried to re-attach control device: " << out[1];
return Sendmsg(fd, "fail");
}
- if (!((*iter)->snapuserd()->InitBackingAndControlDevice())) {
- LOG(ERROR) << "Failed to initialize control device: " << out[1];
+ if (!StartHandler(*iter)) {
return Sendmsg(fd, "fail");
}
- (*iter)->thread() = std::thread(std::bind(&SnapuserdServer::RunThread, this, *iter));
return Sendmsg(fd, "success");
}
case DaemonOperations::STOP: {
@@ -340,6 +326,39 @@
SetTerminating();
}
+std::shared_ptr<DmUserHandler> SnapuserdServer::AddHandler(const std::string& misc_name,
+ const std::string& cow_device_path,
+ const std::string& backing_device) {
+ auto snapuserd = std::make_unique<Snapuserd>(misc_name, cow_device_path, backing_device);
+ if (!snapuserd->InitCowDevice()) {
+ LOG(ERROR) << "Failed to initialize Snapuserd";
+ return nullptr;
+ }
+
+ auto handler = std::make_shared<DmUserHandler>(std::move(snapuserd));
+ {
+ std::lock_guard<std::mutex> lock(lock_);
+ if (FindHandler(&lock, misc_name) != dm_users_.end()) {
+ LOG(ERROR) << "Handler already exists: " << misc_name;
+ return nullptr;
+ }
+ dm_users_.push_back(handler);
+ }
+ return handler;
+}
+
+bool SnapuserdServer::StartHandler(const std::shared_ptr<DmUserHandler>& handler) {
+ CHECK(!handler->snapuserd()->IsAttached());
+
+ if (!handler->snapuserd()->InitBackingAndControlDevice()) {
+ LOG(ERROR) << "Failed to initialize control device: " << handler->GetMiscName();
+ return false;
+ }
+
+ handler->thread() = std::thread(std::bind(&SnapuserdServer::RunThread, this, handler));
+ return true;
+}
+
auto SnapuserdServer::FindHandler(std::lock_guard<std::mutex>* proof_of_lock,
const std::string& misc_name) -> HandlerList::iterator {
CHECK(proof_of_lock);
diff --git a/fs_mgr/libsnapshot/snapuserd_server.h b/fs_mgr/libsnapshot/snapuserd_server.h
index 6e897aa..01e2365 100644
--- a/fs_mgr/libsnapshot/snapuserd_server.h
+++ b/fs_mgr/libsnapshot/snapuserd_server.h
@@ -103,7 +103,6 @@
std::string GetDaemonStatus();
void Parsemsg(std::string const& msg, const char delim, std::vector<std::string>& out);
- void SetTerminating() { terminating_ = true; }
bool IsTerminating() { return terminating_; }
void RunThread(std::shared_ptr<DmUserHandler> handler);
@@ -120,6 +119,13 @@
bool Start(const std::string& socketname);
bool Run();
void Interrupt();
+
+ std::shared_ptr<DmUserHandler> AddHandler(const std::string& misc_name,
+ const std::string& cow_device_path,
+ const std::string& backing_device);
+ bool StartHandler(const std::shared_ptr<DmUserHandler>& handler);
+
+ void SetTerminating() { terminating_ = true; }
};
} // namespace snapshot