magic_xattr.h

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#ifndef CVMFS_MAGIC_XATTR_H_
#define CVMFS_MAGIC_XATTR_H_

#include <map>
#include <set>
#include <string>

#include "backoff.h"
#include "catalog_counters.h"
#include "directory_entry.h"
#include "shortstring.h"
#include "util/exception.h"
#include "util/string.h"

class MountPoint;

enum MagicXattrFlavor {
  kXattrBase = 0,
  kXattrWithHash,
  kXattrRegular,
  kXattrExternal,
  kXattrSymlink,
  kXattrAuthz
};

class MagicXattrManager;  // needed for BaseMagicXattr
class BaseMagicXattr {
  friend class MagicXattrManager;
  FRIEND_TEST(T_MagicXattr, ProtectedXattr);
  FRIEND_TEST(T_MagicXattr, TestFqrn);
  FRIEND_TEST(T_MagicXattr, TestLogBuffer);

 public:
  BaseMagicXattr() : is_protected_(false) {
    int retval = pthread_mutex_init(&access_mutex_, NULL);
    assert(retval == 0);
  }

  void MarkProtected() {
    is_protected_ = true;
  }


  // TODO(hereThereBeDragons) from C++11 should be marked final
  bool PrepareValueFencedProtected(gid_t gid);

  virtual std::string GetValue() = 0;
  virtual MagicXattrFlavor GetXattrFlavor() { return kXattrBase; }

  void Lock(PathString path, catalog::DirectoryEntry *dirent) {
    int retval = pthread_mutex_lock(&access_mutex_);
    assert(retval == 0);
    path_ = path;
    dirent_ = dirent;
  }
  void Release() {
    int retval = pthread_mutex_unlock(&access_mutex_);
    assert(retval == 0);
  }

  virtual ~BaseMagicXattr() {}

 protected:
  virtual bool PrepareValueFenced() { return true; }

  MagicXattrManager *xattr_mgr_;
  PathString path_;
  catalog::DirectoryEntry *dirent_;

  pthread_mutex_t access_mutex_;
  bool is_protected_;
};

class MagicXattrRAIIWrapper: public SingleCopy {
 public:
  inline MagicXattrRAIIWrapper() : ptr_(NULL) { }

  inline explicit MagicXattrRAIIWrapper(
    BaseMagicXattr *ptr,
    PathString path,
    catalog::DirectoryEntry *d)
    : ptr_(ptr)
  {
    if (ptr_ != NULL) ptr_->Lock(path, d);
  }
  inline explicit MagicXattrRAIIWrapper(BaseMagicXattr *ptr) : ptr_(ptr) { }

  inline ~MagicXattrRAIIWrapper() { if (ptr_ != NULL) ptr_->Release(); }

  inline BaseMagicXattr* operator->() const { return ptr_; }
  inline bool IsNull() const { return ptr_ == NULL; }
  inline BaseMagicXattr* Move() {
    BaseMagicXattr* ret = ptr_;
    ptr_ = NULL;
    return ret;
  }

 protected:
  BaseMagicXattr *ptr_;
};

class WithHashMagicXattr : public BaseMagicXattr {
  virtual MagicXattrFlavor GetXattrFlavor() { return kXattrWithHash; }
};

class RegularMagicXattr : public BaseMagicXattr {
  virtual MagicXattrFlavor GetXattrFlavor() { return kXattrRegular; }
};

class ExternalMagicXattr : public BaseMagicXattr {
  virtual MagicXattrFlavor GetXattrFlavor() { return kXattrExternal; }
};

class SymlinkMagicXattr : public BaseMagicXattr {
  virtual MagicXattrFlavor GetXattrFlavor() { return kXattrSymlink; }
};

class MagicXattrManager : public SingleCopy {
 public:
  enum EVisibility { kVisibilityAlways, kVisibilityNever, kVisibilityRootOnly };

  MagicXattrManager(MountPoint *mountpoint, EVisibility visibility,
                    const std::set<std::string> &protected_xattrs,
                    const std::set<gid_t> &privileged_xattr_gids);
  BaseMagicXattr* GetLocked(const std::string &name, PathString path,
                            catalog::DirectoryEntry *d);
  std::string GetListString(catalog::DirectoryEntry *dirent);
  void Register(const std::string &name, BaseMagicXattr *magic_xattr);

  void Freeze() { is_frozen_ = true; SanityCheckProtectedXattrs(); }
  bool IsPrivilegedGid(gid_t gid);


  EVisibility visibility() { return visibility_; }
  std::set<gid_t> privileged_xattr_gids()
                                { return privileged_xattr_gids_; }
  MountPoint* mount_point() { return mount_point_; }
  bool is_frozen() const { return is_frozen_; }

 protected:
  std::map<std::string, BaseMagicXattr *> xattr_list_;
  MountPoint *mount_point_;
  EVisibility visibility_;

  // privileged_xattr_gids_ contains the (fuse) gids that
  // can access xattrs that are part of protected_xattrs_
  const std::set<std::string> protected_xattrs_;
  const std::set<gid_t> privileged_xattr_gids_;

 private:
  bool is_frozen_;

  void SanityCheckProtectedXattrs();
};

class AuthzMagicXattr : public BaseMagicXattr {
  virtual bool PrepareValueFenced();
  virtual std::string GetValue();
  virtual MagicXattrFlavor GetXattrFlavor();
};

class CatalogCountersMagicXattr : public BaseMagicXattr {
  std::string subcatalog_path_;
  shash::Any hash_;
  catalog::Counters counters_;

  virtual bool PrepareValueFenced();
  virtual std::string GetValue();
};

class ChunkListMagicXattr : public RegularMagicXattr {
  std::string chunk_list_;

  virtual bool PrepareValueFenced();
  virtual std::string GetValue();
};

class ChunksMagicXattr : public RegularMagicXattr {
  uint64_t n_chunks_;

  virtual bool PrepareValueFenced();
  virtual std::string GetValue();
};

class CompressionMagicXattr : public RegularMagicXattr {
  virtual bool PrepareValueFenced();
  virtual std::string GetValue();
};

class DirectIoMagicXattr : public RegularMagicXattr {
  virtual bool PrepareValueFenced();
  virtual std::string GetValue();
};

class ExternalFileMagicXattr : public RegularMagicXattr {
  virtual bool PrepareValueFenced();
  virtual std::string GetValue();
};

class ExternalHostMagicXattr : public BaseMagicXattr {
  virtual std::string GetValue();
};

class ExternalTimeoutMagicXattr : public BaseMagicXattr {
  virtual std::string GetValue();
};

class FqrnMagicXattr : public BaseMagicXattr {
  virtual std::string GetValue();
};

class HashMagicXattr : public WithHashMagicXattr {
  virtual bool PrepareValueFenced();
  virtual std::string GetValue();
};

class HostMagicXattr : public BaseMagicXattr {
  virtual std::string GetValue();
};

class HostListMagicXattr : public BaseMagicXattr {
  virtual std::string GetValue();
};

class LHashMagicXattr : public WithHashMagicXattr {
  virtual bool PrepareValueFenced();
  virtual std::string GetValue();
};

class LogBufferXattr : public BaseMagicXattr {
 public:
  LogBufferXattr();

 private:
  const unsigned int kMaxLogLine = 4096;  // longer log lines are trimmed
  // Generating the log buffer report involves 64 string copies. To mitigate
  // memory fragmentation and performance loss, throttle the use of this
  // attribute a little.
  BackoffThrottle throttle_;

  virtual std::string GetValue();
};

class NCleanup24MagicXattr : public BaseMagicXattr {
  virtual std::string GetValue();
};

class NClgMagicXattr : public BaseMagicXattr {
  int n_catalogs_;

  virtual bool PrepareValueFenced();
  virtual std::string GetValue();
};

class NDirOpenMagicXattr : public BaseMagicXattr {
  virtual std::string GetValue();
};

class NDownloadMagicXattr : public BaseMagicXattr {
  virtual std::string GetValue();
};

class NIOErrMagicXattr : public BaseMagicXattr {
  virtual std::string GetValue();
};

class NOpenMagicXattr : public BaseMagicXattr {
  virtual std::string GetValue();
};

class HitrateMagicXattr : public BaseMagicXattr {
  virtual std::string GetValue();
};

class ProxyMagicXattr : public BaseMagicXattr {
  virtual std::string GetValue();
};

class PubkeysMagicXattr : public BaseMagicXattr {
  std::string pubkeys_;

  virtual bool PrepareValueFenced();
  virtual std::string GetValue();
};

class RawlinkMagicXattr : public SymlinkMagicXattr {
  virtual bool PrepareValueFenced();
  virtual std::string GetValue();
};

class RepoCountersMagicXattr : public BaseMagicXattr {
  catalog::Counters counters_;

  virtual bool PrepareValueFenced();
  virtual std::string GetValue();
};

class RepoMetainfoMagicXattr : public BaseMagicXattr {
  static uint64_t kMaxMetainfoLength;

  shash::Any metainfo_hash_;
  std::string error_reason_;

  virtual bool PrepareValueFenced();
  virtual std::string GetValue();
};

class RevisionMagicXattr : public BaseMagicXattr {
  uint64_t revision_;

  virtual bool PrepareValueFenced();
  virtual std::string GetValue();
};

class RootHashMagicXattr : public BaseMagicXattr {
  shash::Any root_hash_;

  virtual bool PrepareValueFenced();
  virtual std::string GetValue();
};

class RxMagicXattr : public BaseMagicXattr {
  virtual std::string GetValue();
};

class SpeedMagicXattr : public BaseMagicXattr {
  virtual std::string GetValue();
};

class TagMagicXattr : public BaseMagicXattr {
  std::string tag_;

  virtual bool PrepareValueFenced();
  virtual std::string GetValue();
};

class TimeoutMagicXattr : public BaseMagicXattr {
  virtual std::string GetValue();
};

class TimeoutDirectMagicXattr : public BaseMagicXattr {
  virtual std::string GetValue();
};

class TimestampLastIOErrMagicXattr : public BaseMagicXattr {
  virtual std::string GetValue();
};

class UsedFdMagicXattr : public BaseMagicXattr {
  virtual std::string GetValue();
};

class UsedDirPMagicXattr : public BaseMagicXattr {
  virtual std::string GetValue();
};

class VersionMagicXattr : public BaseMagicXattr {
  virtual std::string GetValue();
};

class ExternalURLMagicXattr : public ExternalMagicXattr {
  virtual bool PrepareValueFenced();
  virtual std::string GetValue();
};

#endif  // CVMFS_MAGIC_XATTR_H_