// Copyright (c) 2012 The Chromium Authors. All rights reserved.

// Use of this source code is governed by a BSD-style license that can be

// found in the LICENSE file.

// This file contains utility functions for dealing with the local

// filesystem.

#ifndef BUTIL_FILE_UTIL_H_

#define BUTIL_FILE_UTIL_H_

#include "butil/build_config.h"

#if defined(OS_WIN)

#include <windows.h>

#elif defined(OS_POSIX)

#include <sys/stat.h>

#include <unistd.h>

#endif

#include <stdio.h>

#include <set>

#include <string>

#include <vector>

#include "butil/base_export.h"

#include "butil/basictypes.h"

#include "butil/files/file.h"

#include "butil/files/file_path.h"

#include "butil/memory/scoped_ptr.h"

#include "butil/strings/string16.h"

#if defined(OS_POSIX)

#include "butil/file_descriptor_posix.h"

#include "butil/logging.h"

#include "butil/posix/eintr_wrapper.h"

#endif

namespace butil {

class Time;

//-----------------------------------------------------------------------------

// Functions that involve filesystem access or modification:

// Returns an absolute version of a relative path. Returns an empty path on

// error. On POSIX, this function fails if the path does not exist. This

// function can result in I/O so it can be slow.

BUTIL_EXPORT FilePath MakeAbsoluteFilePath(const FilePath& input);

// Returns the total number of bytes used by all the files under |root_path|.

// If the path does not exist the function returns 0.

//

// This function is implemented using the FileEnumerator class so it is not

// particularly speedy in any platform.

BUTIL_EXPORT int64_t ComputeDirectorySize(const FilePath& root_path);

// Deletes the given path, whether it's a file or a directory.

// If it's a directory, it's perfectly happy to delete all of the

// directory's contents.  Passing true to recursive deletes

// subdirectories and their contents as well.

// Returns true if successful, false otherwise. It is considered successful

// to attempt to delete a file that does not exist.

//

// In posix environment and if |path| is a symbolic link, this deletes only

// the symlink. (even if the symlink points to a non-existent file)

//

// WARNING: USING THIS WITH recursive==true IS EQUIVALENT

//          TO "rm -rf", SO USE WITH CAUTION.

BUTIL_EXPORT bool DeleteFile(const FilePath& path, bool recursive);

#if defined(OS_WIN)

// Schedules to delete the given path, whether it's a file or a directory, until

// the operating system is restarted.

// Note:

// 1) The file/directory to be deleted should exist in a temp folder.

// 2) The directory to be deleted must be empty.

BUTIL_EXPORT bool DeleteFileAfterReboot(const FilePath& path);

#endif

// Moves the given path, whether it's a file or a directory.

// If a simple rename is not possible, such as in the case where the paths are

// on different volumes, this will attempt to copy and delete. Returns

// true for success.

// This function fails if either path contains traversal components ('..').

BUTIL_EXPORT bool Move(const FilePath& from_path, const FilePath& to_path);

// Renames file |from_path| to |to_path|. Both paths must be on the same

// volume, or the function will fail. Destination file will be created

// if it doesn't exist. Prefer this function over Move when dealing with

// temporary files. On Windows it preserves attributes of the target file.

// Returns true on success, leaving *error unchanged.

// Returns false on failure and sets *error appropriately, if it is non-NULL.

BUTIL_EXPORT bool ReplaceFile(const FilePath& from_path,

                             const FilePath& to_path,

                             File::Error* error);

// Copies a single file. Use CopyDirectory to copy directories.

// This function fails if either path contains traversal components ('..').

//

// This function keeps the metadata on Windows. The read only bit on Windows is

// not kept.

BUTIL_EXPORT bool CopyFile(const FilePath& from_path, const FilePath& to_path);

// Copies the given path, and optionally all subdirectories and their contents

// as well.

//

// If there are files existing under to_path, always overwrite. Returns true

// if successful, false otherwise. Wildcards on the names are not supported.

//

// This function calls into CopyFile() so the same behavior w.r.t. metadata

// applies.

//

// If you only need to copy a file use CopyFile, it's faster.

BUTIL_EXPORT bool CopyDirectory(const FilePath& from_path,

                               const FilePath& to_path,

                               bool recursive);

// Returns true if the given path exists on the local filesystem,

// false otherwise.

BUTIL_EXPORT bool PathExists(const FilePath& path);

// Returns true if the given path is writable by the user, false otherwise.

BUTIL_EXPORT bool PathIsWritable(const FilePath& path);

// Returns true if the given path exists and is a directory, false otherwise.

BUTIL_EXPORT bool DirectoryExists(const FilePath& path);

// Returns true if the contents of the two files given are equal, false

// otherwise.  If either file can't be read, returns false.

BUTIL_EXPORT bool ContentsEqual(const FilePath& filename1,

                               const FilePath& filename2);

// Returns true if the contents of the two text files given are equal, false

// otherwise.  This routine treats "\r\n" and "\n" as equivalent.

BUTIL_EXPORT bool TextContentsEqual(const FilePath& filename1,

                                   const FilePath& filename2);

// Reads the file at |path| into |contents| and returns true on success and

// false on error.  For security reasons, a |path| containing path traversal

// components ('..') is treated as a read error and |contents| is set to empty.

// In case of I/O error, |contents| holds the data that could be read from the

// file before the error occurred.

// |contents| may be NULL, in which case this function is useful for its side

// effect of priming the disk cache (could be used for unit tests).

BUTIL_EXPORT bool ReadFileToString(const FilePath& path, std::string* contents);

// Reads the file at |path| into |contents| and returns true on success and

// false on error.  For security reasons, a |path| containing path traversal

// components ('..') is treated as a read error and |contents| is set to empty.

// In case of I/O error, |contents| holds the data that could be read from the

// file before the error occurred.  When the file size exceeds |max_size|, the

// function returns false with |contents| holding the file truncated to

// |max_size|.

// |contents| may be NULL, in which case this function is useful for its side

// effect of priming the disk cache (could be used for unit tests).

BUTIL_EXPORT bool ReadFileToString(const FilePath& path,

                                  std::string* contents,

                                  size_t max_size);

#if defined(OS_POSIX)

// Read exactly |bytes| bytes from file descriptor |fd|, storing the result

// in |buffer|. This function is protected against EINTR and partial reads.

// Returns true iff |bytes| bytes have been successfully read from |fd|.

BUTIL_EXPORT bool ReadFromFD(int fd, char* buffer, size_t bytes);

// Creates a symbolic link at |symlink| pointing to |target|.  Returns

// false on failure.

BUTIL_EXPORT bool CreateSymbolicLink(const FilePath& target,

                                    const FilePath& symlink);

// Reads the given |symlink| and returns where it points to in |target|.

// Returns false upon failure.

BUTIL_EXPORT bool ReadSymbolicLink(const FilePath& symlink, FilePath* target);

// Bits and masks of the file permission.

enum FilePermissionBits {

  FILE_PERMISSION_MASK              = S_IRWXU | S_IRWXG | S_IRWXO,

  FILE_PERMISSION_USER_MASK         = S_IRWXU,

  FILE_PERMISSION_GROUP_MASK        = S_IRWXG,

  FILE_PERMISSION_OTHERS_MASK       = S_IRWXO,

  FILE_PERMISSION_READ_BY_USER      = S_IRUSR,

  FILE_PERMISSION_WRITE_BY_USER     = S_IWUSR,

  FILE_PERMISSION_EXECUTE_BY_USER   = S_IXUSR,

  FILE_PERMISSION_READ_BY_GROUP     = S_IRGRP,

  FILE_PERMISSION_WRITE_BY_GROUP    = S_IWGRP,

  FILE_PERMISSION_EXECUTE_BY_GROUP  = S_IXGRP,

  FILE_PERMISSION_READ_BY_OTHERS    = S_IROTH,

  FILE_PERMISSION_WRITE_BY_OTHERS   = S_IWOTH,

  FILE_PERMISSION_EXECUTE_BY_OTHERS = S_IXOTH,

};

// Reads the permission of the given |path|, storing the file permission

// bits in |mode|. If |path| is symbolic link, |mode| is the permission of

// a file which the symlink points to.

BUTIL_EXPORT bool GetPosixFilePermissions(const FilePath& path, int* mode);

// Sets the permission of the given |path|. If |path| is symbolic link, sets

// the permission of a file which the symlink points to.

BUTIL_EXPORT bool SetPosixFilePermissions(const FilePath& path, int mode);

#endif  // OS_POSIX

// Returns true if the given directory is empty

BUTIL_EXPORT bool IsDirectoryEmpty(const FilePath& dir_path);

// Get the temporary directory provided by the system.

//

// WARNING: In general, you should use CreateTemporaryFile variants below

// instead of this function. Those variants will ensure that the proper

// permissions are set so that other users on the system can't edit them while

// they're open (which can lead to security issues).

BUTIL_EXPORT bool GetTempDir(FilePath* path);

// Get the home directory. This is more complicated than just getenv("HOME")

// as it knows to fall back on getpwent() etc.

//

// You should not generally call this directly. Instead use DIR_HOME with the

// path service which will use this function but cache the value.

// Path service may also override DIR_HOME.

BUTIL_EXPORT FilePath GetHomeDir();

// Creates a temporary file. The full path is placed in |path|, and the

// function returns true if was successful in creating the file. The file will

// be empty and all handles closed after this function returns.

BUTIL_EXPORT bool CreateTemporaryFile(FilePath* path);

// Same as CreateTemporaryFile but the file is created in |dir|.

BUTIL_EXPORT bool CreateTemporaryFileInDir(const FilePath& dir,

                                          FilePath* temp_file);

// Create and open a temporary file.  File is opened for read/write.

// The full path is placed in |path|.

// Returns a handle to the opened file or NULL if an error occurred.

BUTIL_EXPORT FILE* CreateAndOpenTemporaryFile(FilePath* path);

// Similar to CreateAndOpenTemporaryFile, but the file is created in |dir|.

BUTIL_EXPORT FILE* CreateAndOpenTemporaryFileInDir(const FilePath& dir,

                                                  FilePath* path);

// Create a new directory. If prefix is provided, the new directory name is in

// the format of prefixyyyy.

// NOTE: prefix is ignored in the POSIX implementation.

// If success, return true and output the full path of the directory created.

BUTIL_EXPORT bool CreateNewTempDirectory(const FilePath::StringType& prefix,

                                        FilePath* new_temp_path);

// Create a directory within another directory.

// Extra characters will be appended to |prefix| to ensure that the

// new directory does not have the same name as an existing directory.

BUTIL_EXPORT bool CreateTemporaryDirInDir(const FilePath& base_dir,

                                         const FilePath::StringType& prefix,

                                         FilePath* new_dir);

// Creates a directory, as well as creating any parent directories by default,

// if they don't exist by default. If |create_parents| is false and the parent

// doesn't exists, false would be returned.

// Returns 'true' on successful creation, or if the directory already exists.

// The directory is readable for all the users.

// Returns true on success, leaving *error unchanged.

// Returns false on failure and sets *error appropriately, if it is non-NULL.

BUTIL_EXPORT bool CreateDirectoryAndGetError(const FilePath& full_path,

                                            File::Error* error);

BUTIL_EXPORT bool CreateDirectoryAndGetError(const FilePath& full_path,

                                            File::Error* error,

                                            bool create_parents);

// Backward-compatible convenience method for the above.

BUTIL_EXPORT bool CreateDirectory(const FilePath& full_path);

BUTIL_EXPORT bool CreateDirectory(const FilePath& full_path, bool create_parents);

// Returns the file size. Returns true on success.

BUTIL_EXPORT bool GetFileSize(const FilePath& file_path, int64_t* file_size);

// Sets |real_path| to |path| with symbolic links and junctions expanded.

// On windows, make sure the path starts with a lettered drive.

// |path| must reference a file.  Function will fail if |path| points to

// a directory or to a nonexistent path.  On windows, this function will

// fail if |path| is a junction or symlink that points to an empty file,

// or if |real_path| would be longer than MAX_PATH characters.

BUTIL_EXPORT bool NormalizeFilePath(const FilePath& path, FilePath* real_path);

#if defined(OS_WIN)

// Given a path in NT native form ("\Device\HarddiskVolumeXX\..."),

// return in |drive_letter_path| the equivalent path that starts with

// a drive letter ("C:\...").  Return false if no such path exists.

BUTIL_EXPORT bool DevicePathToDriveLetterPath(const FilePath& device_path,

                                             FilePath* drive_letter_path);

// Given an existing file in |path|, set |real_path| to the path

// in native NT format, of the form "\Device\HarddiskVolumeXX\..".

// Returns false if the path can not be found. Empty files cannot

// be resolved with this function.

BUTIL_EXPORT bool NormalizeToNativeFilePath(const FilePath& path,

                                           FilePath* nt_path);

#endif

// This function will return if the given file is a symlink or not.

BUTIL_EXPORT bool IsLink(const FilePath& file_path);

// Returns information about the given file path.

BUTIL_EXPORT bool GetFileInfo(const FilePath& file_path, File::Info* info);

// Sets the time of the last access and the time of the last modification.

BUTIL_EXPORT bool TouchFile(const FilePath& path,

                           const Time& last_accessed,

                           const Time& last_modified);

// Wrapper for fopen-like calls. Returns non-NULL FILE* on success.

BUTIL_EXPORT FILE* OpenFile(const FilePath& filename, const char* mode);

// Closes file opened by OpenFile. Returns true on success.

BUTIL_EXPORT bool CloseFile(FILE* file);

// Associates a standard FILE stream with an existing File. Note that this

// functions take ownership of the existing File.

BUTIL_EXPORT FILE* FileToFILE(File file, const char* mode);

// Truncates an open file to end at the location of the current file pointer.

// This is a cross-platform analog to Windows' SetEndOfFile() function.

BUTIL_EXPORT bool TruncateFile(FILE* file);

// Reads at most the given number of bytes from the file into the buffer.

// Returns the number of read bytes, or -1 on error.

BUTIL_EXPORT int ReadFile(const FilePath& filename, char* data, int max_size);

// Writes the given buffer into the file, overwriting any data that was

// previously there.  Returns the number of bytes written, or -1 on error.

BUTIL_EXPORT int WriteFile(const FilePath& filename, const char* data,

                          int size);

#if defined(OS_POSIX)

// Append the data to |fd|. Does not close |fd| when done.

BUTIL_EXPORT int WriteFileDescriptor(const int fd, const char* data, int size);

#endif

// Append the given buffer into the file. Returns the number of bytes written,

// or -1 on error.

BUTIL_EXPORT int AppendToFile(const FilePath& filename,

                             const char* data, int size);

// Gets the current working directory for the process.

BUTIL_EXPORT bool GetCurrentDirectory(FilePath* path);

// Sets the current working directory for the process.

BUTIL_EXPORT bool SetCurrentDirectory(const FilePath& path);

// Attempts to find a number that can be appended to the |path| to make it

// unique. If |path| does not exist, 0 is returned.  If it fails to find such

// a number, -1 is returned. If |suffix| is not empty, also checks the

// existence of it with the given suffix.

BUTIL_EXPORT int GetUniquePathNumber(const FilePath& path,

                                    const FilePath::StringType& suffix);

#if defined(OS_POSIX)

// Test that |path| can only be changed by a given user and members of

// a given set of groups.

// Specifically, test that all parts of |path| under (and including) |base|:

// * Exist.

// * Are owned by a specific user.

// * Are not writable by all users.

// * Are owned by a member of a given set of groups, or are not writable by

//   their group.

// * Are not symbolic links.

// This is useful for checking that a config file is administrator-controlled.

// |base| must contain |path|.

BUTIL_EXPORT bool VerifyPathControlledByUser(const butil::FilePath& base,

                                            const butil::FilePath& path,

                                            uid_t owner_uid,

                                            const std::set<gid_t>& group_gids);

#endif  // defined(OS_POSIX)

#if defined(OS_MACOSX) && !defined(OS_IOS)

// Is |path| writable only by a user with administrator privileges?

// This function uses Mac OS conventions.  The super user is assumed to have

// uid 0, and the administrator group is assumed to be named "admin".

// Testing that |path|, and every parent directory including the root of

// the filesystem, are owned by the superuser, controlled by the group

// "admin", are not writable by all users, and contain no symbolic links.

// Will return false if |path| does not exist.

BUTIL_EXPORT bool VerifyPathControlledByAdmin(const butil::FilePath& path);

#endif  // defined(OS_MACOSX) && !defined(OS_IOS)

// Returns the maximum length of path component on the volume containing

// the directory |path|, in the number of FilePath::CharType, or -1 on failure.

BUTIL_EXPORT int GetMaximumPathComponentLength(const butil::FilePath& path);

#if defined(OS_LINUX)

// Broad categories of file systems as returned by statfs() on Linux.

enum FileSystemType {

  FILE_SYSTEM_UNKNOWN,  // statfs failed.

  FILE_SYSTEM_0,        // statfs.f_type == 0 means unknown, may indicate AFS.

  FILE_SYSTEM_ORDINARY,       // on-disk filesystem like ext2

  FILE_SYSTEM_NFS,

  FILE_SYSTEM_SMB,

  FILE_SYSTEM_CODA,

  FILE_SYSTEM_MEMORY,         // in-memory file system

  FILE_SYSTEM_CGROUP,         // cgroup control.

  FILE_SYSTEM_OTHER,          // any other value.

  FILE_SYSTEM_TYPE_COUNT

};

// Attempts determine the FileSystemType for |path|.

// Returns false if |path| doesn't exist.

BUTIL_EXPORT bool GetFileSystemType(const FilePath& path, FileSystemType* type);

#endif

#if defined(OS_POSIX)

// Get a temporary directory for shared memory files. The directory may depend

// on whether the destination is intended for executable files, which in turn

// depends on how /dev/shmem was mounted. As a result, you must supply whether

// you intend to create executable shmem segments so this function can find

// an appropriate location.

BUTIL_EXPORT bool GetShmemTempDir(bool executable, FilePath* path);

#endif

}  // namespace butil

// -----------------------------------------------------------------------------

namespace file_util {

// Functor for |ScopedFILE| (below).

struct ScopedFILEClose {

  inline void operator()(FILE* x) const {

    if (x)

      fclose(x);

  }

};

// Automatically closes |FILE*|s.

typedef scoped_ptr<FILE, ScopedFILEClose> ScopedFILE;

}  // namespace file_util

// Internal --------------------------------------------------------------------

namespace butil {

namespace internal {

// Same as Move but allows paths with traversal components.

// Use only with extreme care.

BUTIL_EXPORT bool MoveUnsafe(const FilePath& from_path,

                            const FilePath& to_path);

// Same as CopyFile but allows paths with traversal components.

// Use only with extreme care.

BUTIL_EXPORT bool CopyFileUnsafe(const FilePath& from_path,

                                const FilePath& to_path);

#if defined(OS_WIN)

// Copy from_path to to_path recursively and then delete from_path recursively.

// Returns true if all operations succeed.

// This function simulates Move(), but unlike Move() it works across volumes.

// This function is not transactional.

BUTIL_EXPORT bool CopyAndDeleteDirectory(const FilePath& from_path,

                                        const FilePath& to_path);

#endif  // defined(OS_WIN)

}  // namespace internal

}  // namespace butil

#endif  // BUTIL_FILE_UTIL_H_