Merge "ueventd: remove PlatformDeviceList"

init/devices.cpp

@@ -147,21 +147,34 @@ void SysfsPermissions::SetPermissions(const std::string& path) const {
     }
 }
 
-// Given a path that may start with a platform device, find the length of the
+// Given a path that may start with a platform device, find the parent platform device by finding a
-// platform device prefix.  If it doesn't start with a platform device, return false
+// parent directory with a 'subsystem' symlink that points to the platform bus.
-bool PlatformDeviceList::Find(const std::string& path, std::string* out_path) const {
+// If it doesn't start with a platform device, return false
-    out_path->clear();
+bool DeviceHandler::FindPlatformDevice(std::string path, std::string* platform_device_path) const {
-    // platform_devices is searched backwards, since parents are added before their children,
+    platform_device_path->clear();
-    // and we want to match as deep of a child as we can.
+
-    for (auto it = platform_devices_.crbegin(); it != platform_devices_.crend(); ++it) {
+    // Uevents don't contain the mount point, so we need to add it here.
-        auto platform_device_path_length = it->length();
+    path.insert(0, sysfs_mount_point_);
-        if (platform_device_path_length < path.length() &&
+
-            path[platform_device_path_length] == '/' &&
+    std::string directory = android::base::Dirname(path);
-            android::base::StartsWith(path, it->c_str())) {
+
-            *out_path = *it;
+    while (directory != "/" && directory != ".") {
+        std::string subsystem_link_path;
+        if (android::base::Realpath(directory + "/subsystem", &subsystem_link_path) &&
+            subsystem_link_path == sysfs_mount_point_ + "/bus/platform") {
+            // We need to remove the mount point that we added above before returning.
+            directory.erase(0, sysfs_mount_point_.size());
+            *platform_device_path = directory;
             return true;
         }
+
+        auto last_slash = path.rfind('/');
+        if (last_slash == std::string::npos) return false;
+
+        path.erase(last_slash);
+        directory = android::base::Dirname(path);
     }
+
     return false;
 }
 
@@ -258,7 +271,7 @@ out:
 
 std::vector<std::string> DeviceHandler::GetCharacterDeviceSymlinks(const Uevent& uevent) const {
     std::string parent_device;
-    if (!platform_devices_.Find(uevent.path, &parent_device)) return {};
+    if (!FindPlatformDevice(uevent.path, &parent_device)) return {};
 
     // skip path to the parent driver
     std::string path = uevent.path.substr(parent_device.length());
@@ -316,7 +329,7 @@ std::vector<std::string> DeviceHandler::GetBlockDeviceSymlinks(const Uevent& uev
     std::string device;
     std::string type;
 
-    if (platform_devices_.Find(uevent.path, &device)) {
+    if (FindPlatformDevice(uevent.path, &device)) {
         // Skip /devices/platform or /devices/ if present
         static const std::string devices_platform_prefix = "/devices/platform/";
         static const std::string devices_prefix = "/devices/";
@@ -388,14 +401,6 @@ void DeviceHandler::HandleDevice(const std::string& action, const std::string& d
     }
 }
 
-void DeviceHandler::HandlePlatformDeviceEvent(const Uevent& uevent) {
-    if (uevent.action == "add") {
-        platform_devices_.Add(uevent.path);
-    } else if (uevent.action == "remove") {
-        platform_devices_.Remove(uevent.path);
-    }
-}
-
 void DeviceHandler::HandleBlockDeviceEvent(const Uevent& uevent) const {
     // if it's not a /dev device, nothing to do
     if (uevent.major < 0 || uevent.minor < 0) return;
@@ -458,8 +463,6 @@ void DeviceHandler::HandleDeviceEvent(const Uevent& uevent) {
 
     if (uevent.subsystem == "block") {
         HandleBlockDeviceEvent(uevent);
-    } else if (uevent.subsystem == "platform") {
-        HandlePlatformDeviceEvent(uevent);
     } else {
         HandleGenericDeviceEvent(uevent);
     }
@@ -472,7 +475,8 @@ DeviceHandler::DeviceHandler(std::vector<Permissions> dev_permissions,
       sysfs_permissions_(std::move(sysfs_permissions)),
       subsystems_(std::move(subsystems)),
       sehandle_(selinux_android_file_context_handle()),
-      skip_restorecon_(skip_restorecon) {}
+      skip_restorecon_(skip_restorecon),
+      sysfs_mount_point_("/sys") {}
 
 DeviceHandler::DeviceHandler()
     : DeviceHandler(std::vector<Permissions>{}, std::vector<SysfsPermissions>{},

init/devices.h

@@ -93,20 +93,6 @@ class Subsystem {
     DevnameSource devname_source_;
 };
 
-class PlatformDeviceList {
-  public:
-    void Add(const std::string& path) { platform_devices_.emplace_back(path); }
-    void Remove(const std::string& path) {
-        auto it = std::find(platform_devices_.begin(), platform_devices_.end(), path);
-        if (it != platform_devices_.end()) platform_devices_.erase(it);
-    }
-    bool Find(const std::string& path, std::string* out_path) const;
-    auto size() const { return platform_devices_.size(); }
-
-  private:
-    std::vector<std::string> platform_devices_;
-};
-
 class DeviceHandler {
   public:
     friend class DeviceHandlerTester;
@@ -119,16 +105,11 @@ class DeviceHandler {
 
     void HandleDeviceEvent(const Uevent& uevent);
 
-    void FixupSysPermissions(const std::string& upath, const std::string& subsystem) const;
-
-    void HandlePlatformDeviceEvent(const Uevent& uevent);
-    void HandleBlockDeviceEvent(const Uevent& uevent) const;
-    void HandleGenericDeviceEvent(const Uevent& uevent) const;
-
     std::vector<std::string> GetBlockDeviceSymlinks(const Uevent& uevent) const;
     void set_skip_restorecon(bool value) { skip_restorecon_ = value; }
 
   private:
+    bool FindPlatformDevice(std::string path, std::string* platform_device_path) const;
     std::tuple<mode_t, uid_t, gid_t> GetDevicePermissions(
         const std::string& path, const std::vector<std::string>& links) const;
     void MakeDevice(const std::string& path, int block, int major, int minor,
@@ -136,13 +117,17 @@ class DeviceHandler {
     std::vector<std::string> GetCharacterDeviceSymlinks(const Uevent& uevent) const;
     void HandleDevice(const std::string& action, const std::string& devpath, int block, int major,
                       int minor, const std::vector<std::string>& links) const;
+    void FixupSysPermissions(const std::string& upath, const std::string& subsystem) const;
+
+    void HandleBlockDeviceEvent(const Uevent& uevent) const;
+    void HandleGenericDeviceEvent(const Uevent& uevent) const;
 
     std::vector<Permissions> dev_permissions_;
     std::vector<SysfsPermissions> sysfs_permissions_;
     std::vector<Subsystem> subsystems_;
-    PlatformDeviceList platform_devices_;
     selabel_handle* sehandle_;
     bool skip_restorecon_;
+    std::string sysfs_mount_point_;
 };
 
 // Exposed for testing

init/devices_test.cpp

@@ -16,33 +16,29 @@
 
 #include "devices.h"
 
-#include <string>
-#include <vector>
-
 #include <android-base/scopeguard.h>
+#include <android-base/test_utils.h>
 #include <gtest/gtest.h>
 
+#include "util.h"
+
+using namespace std::string_literals;
+
 class DeviceHandlerTester {
   public:
-    void AddPlatformDevice(const std::string& path) {
+    void TestGetSymlinks(const std::string& platform_device, const Uevent& uevent,
-        Uevent uevent = {
-            .action = "add", .subsystem = "platform", .path = path,
-        };
-        device_handler_.HandlePlatformDeviceEvent(uevent);
-    }
-
-    void RemovePlatformDevice(const std::string& path) {
-        Uevent uevent = {
-            .action = "remove", .subsystem = "platform", .path = path,
-        };
-        device_handler_.HandlePlatformDeviceEvent(uevent);
-    }
-
-    void TestGetSymlinks(const std::string& platform_device_name, const Uevent& uevent,
                          const std::vector<std::string> expected_links, bool block) {
-        AddPlatformDevice(platform_device_name);
+        TemporaryDir fake_sys_root;
-        auto platform_device_remover = android::base::make_scope_guard(
+        device_handler_.sysfs_mount_point_ = fake_sys_root.path;
-            [this, &platform_device_name]() { RemovePlatformDevice(platform_device_name); });
+
+        std::string platform_device_dir = fake_sys_root.path + platform_device;
+        mkdir_recursive(platform_device_dir, 0777, nullptr);
+
+        std::string platform_bus = fake_sys_root.path + "/bus/platform"s;
+        mkdir_recursive(platform_bus, 0777, nullptr);
+        symlink(platform_bus.c_str(), (platform_device_dir + "/subsystem").c_str());
+
+        mkdir_recursive(android::base::Dirname(fake_sys_root.path + uevent.path), 0777, nullptr);
 
         std::vector<std::string> result;
         if (block) {
@@ -65,30 +61,6 @@ class DeviceHandlerTester {
     DeviceHandler device_handler_;
 };
 
-TEST(device_handler, PlatformDeviceList) {
-    PlatformDeviceList platform_device_list;
-
-    platform_device_list.Add("/devices/platform/some_device_name");
-    platform_device_list.Add("/devices/platform/some_device_name/longer");
-    platform_device_list.Add("/devices/platform/other_device_name");
-    EXPECT_EQ(3U, platform_device_list.size());
-
-    std::string out_path;
-    EXPECT_FALSE(platform_device_list.Find("/devices/platform/not_found", &out_path));
-    EXPECT_EQ("", out_path);
-
-    EXPECT_FALSE(platform_device_list.Find("/devices/platform/some_device_name_with_same_prefix",
-                                           &out_path));
-
-    EXPECT_TRUE(platform_device_list.Find("/devices/platform/some_device_name/longer/longer_child",
-                                          &out_path));
-    EXPECT_EQ("/devices/platform/some_device_name/longer", out_path);
-
-    EXPECT_TRUE(
-        platform_device_list.Find("/devices/platform/some_device_name/other_child", &out_path));
-    EXPECT_EQ("/devices/platform/some_device_name", out_path);
-}
-
 TEST(device_handler, get_character_device_symlinks_success) {
     const char* platform_device = "/devices/platform/some_device_name";
     Uevent uevent = {

init/init_first_stage.cpp

@@ -181,12 +181,6 @@ void FirstStageMount::InitRequiredDevices() {
 }
 
 RegenerationAction FirstStageMount::UeventCallback(const Uevent& uevent) {
-    // We need platform devices to create symlinks.
-    if (uevent.subsystem == "platform") {
-        device_handler_.HandleDeviceEvent(uevent);
-        return RegenerationAction::kContinue;
-    }
-
     // Ignores everything that is not a block device.
     if (uevent.subsystem != "block") {
         return RegenerationAction::kContinue;

init/ueventd.cpp

@@ -128,15 +128,7 @@ class ColdBoot {
 void ColdBoot::UeventHandlerMain(unsigned int process_num, unsigned int total_processes) {
     for (unsigned int i = process_num; i < uevent_queue_.size(); i += total_processes) {
         auto& uevent = uevent_queue_[i];
-        if (uevent.action == "add" || uevent.action == "change" || uevent.action == "online") {
+        device_handler_.HandleDeviceEvent(uevent);
-            device_handler_.FixupSysPermissions(uevent.path, uevent.subsystem);
-        }
-
-        if (uevent.subsystem == "block") {
-            device_handler_.HandleBlockDeviceEvent(uevent);
-        } else {
-            device_handler_.HandleGenericDeviceEvent(uevent);
-        }
     }
     _exit(EXIT_SUCCESS);
 }
@@ -145,14 +137,6 @@ void ColdBoot::RegenerateUevents() {
     uevent_listener_.RegenerateUevents([this](const Uevent& uevent) {
         HandleFirmwareEvent(uevent);
 
-        // This is the one mutable part of DeviceHandler, in which platform devices are
-        // added to a vector for later reference.  Since there is no communication after
-        // fork()'ing subprocess handlers, all platform devices must be in the vector before
-        // we fork, and therefore they must be handled in this loop.
-        if (uevent.subsystem == "platform") {
-            device_handler_.HandlePlatformDeviceEvent(uevent);
-        }
-
         uevent_queue_.emplace_back(std::move(uevent));
         return RegenerationAction::kContinue;
     });