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Commit 18173b1e authored by Rick Yiu's avatar Rick Yiu Committed by Automerger Merge Worker
Browse files

Merge "libprocessgroup: Use WriteStringToFd for WriteFileAction" am: 9dfff253 

Original change: https://android-review.googlesource.com/c/platform/system/core/+/1895031

Change-Id: Ifbe096257f40ca43e12b6f4156c1c146c3916794
parents 270aca8a 9dfff253

libprocessgroup/task_profiles.cpp

+74 −35
Original line number Diff line number Diff line
@@ -144,30 +144,13 @@ bool SetAttributeAction::ExecuteForTask(int tid) const { 
    return true;

}



bool SetCgroupAction::IsAppDependentPath(const std::string& path) {

    return path.find("<uid>", 0) != std::string::npos || path.find("<pid>", 0) != std::string::npos;

}



SetCgroupAction::SetCgroupAction(const CgroupController& c, const std::string& p)

    : controller_(c), path_(p) {

    // file descriptors for app-dependent paths can't be cached

    if (IsAppDependentPath(path_)) {

        // file descriptor is not cached

        fd_.reset(FDS_APP_DEPENDENT);

        return;

    }



    // file descriptor can be cached later on request

    fd_.reset(FDS_NOT_CACHED);

}



void SetCgroupAction::EnableResourceCaching() {

void CachedFdProfileAction::EnableResourceCaching() {

    std::lock_guard<std::mutex> lock(fd_mutex_);

    if (fd_ != FDS_NOT_CACHED) {

        return;

    }



    std::string tasks_path = controller_.GetTasksFilePath(path_);

    std::string tasks_path = GetPath();



    if (access(tasks_path.c_str(), W_OK) != 0) {

        // file is not accessible
@@ -185,7 +168,7 @@ void SetCgroupAction::EnableResourceCaching() { 
    fd_ = std::move(fd);

}



void SetCgroupAction::DropResourceCaching() {

void CachedFdProfileAction::DropResourceCaching() {

    std::lock_guard<std::mutex> lock(fd_mutex_);

    if (fd_ == FDS_NOT_CACHED) {

        return;
@@ -194,6 +177,26 @@ void SetCgroupAction::DropResourceCaching() { 
    fd_.reset(FDS_NOT_CACHED);

}



bool CachedFdProfileAction::IsAppDependentPath(const std::string& path) {

    return path.find("<uid>", 0) != std::string::npos || path.find("<pid>", 0) != std::string::npos;

}



void CachedFdProfileAction::InitFd(const std::string& path) {

    // file descriptors for app-dependent paths can't be cached

    if (IsAppDependentPath(path)) {

        // file descriptor is not cached

        fd_.reset(FDS_APP_DEPENDENT);

        return;

    }

    // file descriptor can be cached later on request

    fd_.reset(FDS_NOT_CACHED);

}



SetCgroupAction::SetCgroupAction(const CgroupController& c, const std::string& p)

    : controller_(c), path_(p) {

    InitFd(controller_.GetTasksFilePath(path_));

}



bool SetCgroupAction::AddTidToCgroup(int tid, int fd, const char* controller_name) {

    if (tid <= 0) {

        return true;
@@ -270,7 +273,7 @@ bool SetCgroupAction::ExecuteForTask(int tid) const { 
    std::string tasks_path = controller()->GetTasksFilePath(path_);

    unique_fd tmp_fd(TEMP_FAILURE_RETRY(open(tasks_path.c_str(), O_WRONLY | O_CLOEXEC)));

    if (tmp_fd < 0) {

        PLOG(WARNING) << "Failed to open " << tasks_path << ": " << strerror(errno);

        PLOG(WARNING) << "Failed to open " << tasks_path;

        return false;

    }

    if (!AddTidToCgroup(tid, tmp_fd, controller()->name())) {
@@ -281,39 +284,75 @@ bool SetCgroupAction::ExecuteForTask(int tid) const { 
    return true;

}



bool WriteFileAction::ExecuteForProcess(uid_t uid, pid_t pid) const {

    std::string filepath(filepath_), value(value_);

WriteFileAction::WriteFileAction(const std::string& path, const std::string& value,

                                 bool logfailures)

    : path_(path), value_(value), logfailures_(logfailures) {

    InitFd(path_);

}



    filepath = StringReplace(filepath, "<uid>", std::to_string(uid), true);

    filepath = StringReplace(filepath, "<pid>", std::to_string(pid), true);

    value = StringReplace(value, "<uid>", std::to_string(uid), true);

    value = StringReplace(value, "<pid>", std::to_string(pid), true);

bool WriteFileAction::WriteValueToFile(const std::string& value, const std::string& path,

                                       bool logfailures) {

    // Use WriteStringToFd instead of WriteStringToFile because the latter will open file with

    // O_TRUNC which causes kernfs_mutex contention

    unique_fd tmp_fd(TEMP_FAILURE_RETRY(open(path.c_str(), O_WRONLY | O_CLOEXEC)));



    if (tmp_fd < 0) {

        if (logfailures) PLOG(WARNING) << "Failed to open " << path;

        return false;

    }



    if (!WriteStringToFile(value, filepath)) {

        if (logfailures_) PLOG(ERROR) << "Failed to write '" << value << "' to " << filepath;

    if (!WriteStringToFd(value, tmp_fd)) {

        if (logfailures) PLOG(ERROR) << "Failed to write '" << value << "' to " << path;

        return false;

    }



    return true;

}



bool WriteFileAction::ExecuteForProcess(uid_t uid, pid_t pid) const {

    std::lock_guard<std::mutex> lock(fd_mutex_);

    std::string value(value_);

    std::string path(path_);



    value = StringReplace(value, "<uid>", std::to_string(uid), true);

    value = StringReplace(value, "<pid>", std::to_string(pid), true);

    path = StringReplace(path, "<uid>", std::to_string(uid), true);

    path = StringReplace(path, "<pid>", std::to_string(pid), true);



    return WriteValueToFile(value, path, logfailures_);

}



bool WriteFileAction::ExecuteForTask(int tid) const {

    std::string filepath(filepath_), value(value_);

    std::lock_guard<std::mutex> lock(fd_mutex_);

    std::string value(value_);

    int uid = getuid();



    filepath = StringReplace(filepath, "<uid>", std::to_string(uid), true);

    filepath = StringReplace(filepath, "<pid>", std::to_string(tid), true);

    value = StringReplace(value, "<uid>", std::to_string(uid), true);

    value = StringReplace(value, "<pid>", std::to_string(tid), true);



    if (!WriteStringToFile(value, filepath)) {

        if (logfailures_) PLOG(ERROR) << "Failed to write '" << value << "' to " << filepath;

    if (IsFdValid()) {

        // fd is cached, reuse it

        if (!WriteStringToFd(value, fd_)) {

            if (logfailures_) PLOG(ERROR) << "Failed to write '" << value << "' to " << path_;

            return false;

        }

        return true;

    }



    if (fd_ == FDS_INACCESSIBLE) {

        // no permissions to access the file, ignore

        return true;

    }



    if (fd_ == FDS_APP_DEPENDENT) {

        // application-dependent path can't be used with tid

        PLOG(ERROR) << "Application profile can't be applied to a thread";

        return false;

    }



    return WriteValueToFile(value, path_, logfailures_);

}



bool ApplyProfileAction::ExecuteForProcess(uid_t uid, pid_t pid) const {

    for (const auto& profile : profiles_) {

        if (!profile->ExecuteForProcess(uid, pid)) {

libprocessgroup/task_profiles.h

+35 −18
Original line number Diff line number Diff line
@@ -108,50 +108,67 @@ class SetAttributeAction : public ProfileAction { 
    std::string value_;

};



// Set cgroup profile element

class SetCgroupAction : public ProfileAction {

// Abstract profile element for cached fd

class CachedFdProfileAction : public ProfileAction {

  public:

    SetCgroupAction(const CgroupController& c, const std::string& p);



    virtual bool ExecuteForProcess(uid_t uid, pid_t pid) const;

    virtual bool ExecuteForTask(int tid) const;

    virtual void EnableResourceCaching();

    virtual void DropResourceCaching();



    const CgroupController* controller() const { return &controller_; }

    std::string path() const { return path_; }



  private:

  protected:

    enum FdState {

        FDS_INACCESSIBLE = -1,

        FDS_APP_DEPENDENT = -2,

        FDS_NOT_CACHED = -3,

    };



    CgroupController controller_;

    std::string path_;

    android::base::unique_fd fd_;

    mutable std::mutex fd_mutex_;



    static bool IsAppDependentPath(const std::string& path);

    static bool AddTidToCgroup(int tid, int fd, const char* controller_name);



    void InitFd(const std::string& path);

    bool IsFdValid() const { return fd_ > FDS_INACCESSIBLE; }



    virtual const std::string GetPath() const = 0;

};



// Set cgroup profile element

class SetCgroupAction : public CachedFdProfileAction {

  public:

    SetCgroupAction(const CgroupController& c, const std::string& p);



    virtual bool ExecuteForProcess(uid_t uid, pid_t pid) const;

    virtual bool ExecuteForTask(int tid) const;



    const CgroupController* controller() const { return &controller_; }



  protected:

    const std::string GetPath() const override { return controller_.GetTasksFilePath(path_); }



  private:

    CgroupController controller_;

    std::string path_;



    static bool AddTidToCgroup(int tid, int fd, const char* controller_name);

};



// Write to file action

class WriteFileAction : public ProfileAction {

class WriteFileAction : public CachedFdProfileAction {

  public:

    WriteFileAction(const std::string& filepath, const std::string& value,

                    bool logfailures) noexcept

        : filepath_(filepath), value_(value), logfailures_(logfailures) {}

    WriteFileAction(const std::string& path, const std::string& value, bool logfailures);



    virtual bool ExecuteForProcess(uid_t uid, pid_t pid) const;

    virtual bool ExecuteForTask(int tid) const;



  protected:

    const std::string GetPath() const override { return path_; }



  private:

    std::string filepath_, value_;

    std::string path_, value_;

    bool logfailures_;



    static bool WriteValueToFile(const std::string& value, const std::string& path,

                                 bool logfailures);

};



class TaskProfile {