// 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 BASE_FILES_FILE_UTIL_H_ #define BASE_FILES_FILE_UTIL_H_ #include <stddef.h> #include <stdint.h> #include <stdio.h> #include <set> #include <string> #include <vector> #include "base/base_export.h" #include "base/files/file.h" #include "base/files/file_path.h" #include "base/memory/scoped_ptr.h" #include "base/strings/string16.h" #include "build/build_config.h" #if defined(OS_WIN) #include <windows.h> #elif defined(OS_POSIX) #include <sys/stat.h> #include <unistd.h> #endif #if defined(OS_POSIX) #include "base/file_descriptor_posix.h" #include "base/logging.h" #include "base/posix/eintr_wrapper.h" #endif namespace base { 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. BASE_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. BASE_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. BASE_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. BASE_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 ('..'). BASE_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. BASE_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. BASE_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. BASE_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. BASE_EXPORT bool PathExists(const FilePath& path); // Returns true if the given path is writable by the user, false otherwise. BASE_EXPORT bool PathIsWritable(const FilePath& path); // Returns true if the given path exists and is a directory, false otherwise. BASE_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. BASE_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. BASE_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). BASE_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). BASE_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|. BASE_EXPORT bool ReadFromFD(int fd, char* buffer, size_t bytes); // Creates a symbolic link at |symlink| pointing to |target|. Returns // false on failure. BASE_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. BASE_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. BASE_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. BASE_EXPORT bool SetPosixFilePermissions(const FilePath& path, int mode); #endif // OS_POSIX // Returns true if the given directory is empty BASE_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). BASE_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. BASE_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. BASE_EXPORT bool CreateTemporaryFile(FilePath* path); // Same as CreateTemporaryFile but the file is created in |dir|. BASE_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. BASE_EXPORT FILE* CreateAndOpenTemporaryFile(FilePath* path); // Similar to CreateAndOpenTemporaryFile, but the file is created in |dir|. BASE_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. BASE_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. BASE_EXPORT bool CreateTemporaryDirInDir(const FilePath& base_dir, const FilePath::StringType& prefix, FilePath* new_dir); // Creates a directory, as well as creating any parent directories, if they // don't exist. Returns 'true' on successful creation, or if the directory // already exists. The directory is only readable by the current user. // Returns true on success, leaving *error unchanged. // Returns false on failure and sets *error appropriately, if it is non-NULL. BASE_EXPORT bool CreateDirectoryAndGetError(const FilePath& full_path, File::Error* error); // Backward-compatible convenience method for the above. BASE_EXPORT bool CreateDirectory(const FilePath& full_path); // Returns the file size. Returns true on success. BASE_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. BASE_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. BASE_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. BASE_EXPORT bool NormalizeToNativeFilePath(const FilePath& path, FilePath* nt_path); #endif // This function will return if the given file is a symlink or not. BASE_EXPORT bool IsLink(const FilePath& file_path); // Returns information about the given file path. BASE_EXPORT bool GetFileInfo(const FilePath& file_path, File::Info* info); // Sets the time of the last access and the time of the last modification. BASE_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. BASE_EXPORT FILE* OpenFile(const FilePath& filename, const char* mode); // Closes file opened by OpenFile. Returns true on success. BASE_EXPORT bool CloseFile(FILE* file); // Associates a standard FILE stream with an existing File. Note that this // functions take ownership of the existing File. BASE_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. BASE_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. BASE_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. BASE_EXPORT int WriteFile(const FilePath& filename, const char* data, int size); #if defined(OS_POSIX) // Appends |data| to |fd|. Does not close |fd| when done. Returns true iff // |size| bytes of |data| were written to |fd|. BASE_EXPORT bool WriteFileDescriptor(const int fd, const char* data, int size); #endif // Appends |data| to |filename|. Returns true iff |size| bytes of |data| were // written to |filename|. BASE_EXPORT bool AppendToFile(const FilePath& filename, const char* data, int size); // Gets the current working directory for the process. BASE_EXPORT bool GetCurrentDirectory(FilePath* path); // Sets the current working directory for the process. BASE_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. BASE_EXPORT int GetUniquePathNumber(const FilePath& path, const FilePath::StringType& suffix); // Sets the given |fd| to non-blocking mode. // Returns true if it was able to set it in the non-blocking mode, otherwise // false. BASE_EXPORT bool SetNonBlocking(int fd); #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|. BASE_EXPORT bool VerifyPathControlledByUser(const base::FilePath& base, const base::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. BASE_EXPORT bool VerifyPathControlledByAdmin(const base::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. BASE_EXPORT int GetMaximumPathComponentLength(const base::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. BASE_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. BASE_EXPORT bool GetShmemTempDir(bool executable, FilePath* path); #endif // Internal -------------------------------------------------------------------- namespace internal { // Same as Move but allows paths with traversal components. // Use only with extreme care. BASE_EXPORT bool MoveUnsafe(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. BASE_EXPORT bool CopyAndDeleteDirectory(const FilePath& from_path, const FilePath& to_path); #endif // defined(OS_WIN) } // namespace internal } // namespace base #endif // BASE_FILES_FILE_UTIL_H_