| // Copyright 2009 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| // Package os provides a platform-independent interface to operating system |
| // functionality. The design is Unix-like, although the error handling is |
| // Go-like; failing calls return values of type error rather than error numbers. |
| // Often, more information is available within the error. For example, |
| // if a call that takes a file name fails, such as Open or Stat, the error |
| // will include the failing file name when printed and will be of type |
| // *PathError, which may be unpacked for more information. |
| // |
| // The os interface is intended to be uniform across all operating systems. |
| // Features not generally available appear in the system-specific package syscall. |
| // |
| // Here is a simple example, opening a file and reading some of it. |
| // |
| // file, err := os.Open("file.go") // For read access. |
| // if err != nil { |
| // log.Fatal(err) |
| // } |
| // |
| // If the open fails, the error string will be self-explanatory, like |
| // |
| // open file.go: no such file or directory |
| // |
| // The file's data can then be read into a slice of bytes. Read and |
| // Write take their byte counts from the length of the argument slice. |
| // |
| // data := make([]byte, 100) |
| // count, err := file.Read(data) |
| // if err != nil { |
| // log.Fatal(err) |
| // } |
| // fmt.Printf("read %d bytes: %q\n", count, data[:count]) |
| // |
| // Note: The maximum number of concurrent operations on a File may be limited by |
| // the OS or the system. The number should be high, but exceeding it may degrade |
| // performance or cause other issues. |
| // |
| package os |
| |
| import ( |
| "errors" |
| "internal/poll" |
| "internal/testlog" |
| "internal/unsafeheader" |
| "io" |
| "io/fs" |
| "runtime" |
| "syscall" |
| "time" |
| "unsafe" |
| ) |
| |
| // Name returns the name of the file as presented to Open. |
| func (f *File) Name() string { return f.name } |
| |
| // Stdin, Stdout, and Stderr are open Files pointing to the standard input, |
| // standard output, and standard error file descriptors. |
| // |
| // Note that the Go runtime writes to standard error for panics and crashes; |
| // closing Stderr may cause those messages to go elsewhere, perhaps |
| // to a file opened later. |
| var ( |
| Stdin = NewFile(uintptr(syscall.Stdin), "/dev/stdin") |
| Stdout = NewFile(uintptr(syscall.Stdout), "/dev/stdout") |
| Stderr = NewFile(uintptr(syscall.Stderr), "/dev/stderr") |
| ) |
| |
| // Flags to OpenFile wrapping those of the underlying system. Not all |
| // flags may be implemented on a given system. |
| const ( |
| // Exactly one of O_RDONLY, O_WRONLY, or O_RDWR must be specified. |
| O_RDONLY int = syscall.O_RDONLY // open the file read-only. |
| O_WRONLY int = syscall.O_WRONLY // open the file write-only. |
| O_RDWR int = syscall.O_RDWR // open the file read-write. |
| // The remaining values may be or'ed in to control behavior. |
| O_APPEND int = syscall.O_APPEND // append data to the file when writing. |
| O_CREATE int = syscall.O_CREAT // create a new file if none exists. |
| O_EXCL int = syscall.O_EXCL // used with O_CREATE, file must not exist. |
| O_SYNC int = syscall.O_SYNC // open for synchronous I/O. |
| O_TRUNC int = syscall.O_TRUNC // truncate regular writable file when opened. |
| ) |
| |
| // Seek whence values. |
| // |
| // Deprecated: Use io.SeekStart, io.SeekCurrent, and io.SeekEnd. |
| const ( |
| SEEK_SET int = 0 // seek relative to the origin of the file |
| SEEK_CUR int = 1 // seek relative to the current offset |
| SEEK_END int = 2 // seek relative to the end |
| ) |
| |
| // LinkError records an error during a link or symlink or rename |
| // system call and the paths that caused it. |
| type LinkError struct { |
| Op string |
| Old string |
| New string |
| Err error |
| } |
| |
| func (e *LinkError) Error() string { |
| return e.Op + " " + e.Old + " " + e.New + ": " + e.Err.Error() |
| } |
| |
| func (e *LinkError) Unwrap() error { |
| return e.Err |
| } |
| |
| // Read reads up to len(b) bytes from the File and stores them in b. |
| // It returns the number of bytes read and any error encountered. |
| // At end of file, Read returns 0, io.EOF. |
| func (f *File) Read(b []byte) (n int, err error) { |
| if err := f.checkValid("read"); err != nil { |
| return 0, err |
| } |
| n, e := f.read(b) |
| return n, f.wrapErr("read", e) |
| } |
| |
| // ReadAt reads len(b) bytes from the File starting at byte offset off. |
| // It returns the number of bytes read and the error, if any. |
| // ReadAt always returns a non-nil error when n < len(b). |
| // At end of file, that error is io.EOF. |
| func (f *File) ReadAt(b []byte, off int64) (n int, err error) { |
| if err := f.checkValid("read"); err != nil { |
| return 0, err |
| } |
| |
| if off < 0 { |
| return 0, &PathError{Op: "readat", Path: f.name, Err: errors.New("negative offset")} |
| } |
| |
| for len(b) > 0 { |
| m, e := f.pread(b, off) |
| if e != nil { |
| err = f.wrapErr("read", e) |
| break |
| } |
| n += m |
| b = b[m:] |
| off += int64(m) |
| } |
| return |
| } |
| |
| // ReadFrom implements io.ReaderFrom. |
| func (f *File) ReadFrom(r io.Reader) (n int64, err error) { |
| if err := f.checkValid("write"); err != nil { |
| return 0, err |
| } |
| n, handled, e := f.readFrom(r) |
| if !handled { |
| return genericReadFrom(f, r) // without wrapping |
| } |
| return n, f.wrapErr("write", e) |
| } |
| |
| func genericReadFrom(f *File, r io.Reader) (int64, error) { |
| return io.Copy(onlyWriter{f}, r) |
| } |
| |
| type onlyWriter struct { |
| io.Writer |
| } |
| |
| // Write writes len(b) bytes from b to the File. |
| // It returns the number of bytes written and an error, if any. |
| // Write returns a non-nil error when n != len(b). |
| func (f *File) Write(b []byte) (n int, err error) { |
| if err := f.checkValid("write"); err != nil { |
| return 0, err |
| } |
| n, e := f.write(b) |
| if n < 0 { |
| n = 0 |
| } |
| if n != len(b) { |
| err = io.ErrShortWrite |
| } |
| |
| epipecheck(f, e) |
| |
| if e != nil { |
| err = f.wrapErr("write", e) |
| } |
| |
| return n, err |
| } |
| |
| var errWriteAtInAppendMode = errors.New("os: invalid use of WriteAt on file opened with O_APPEND") |
| |
| // WriteAt writes len(b) bytes to the File starting at byte offset off. |
| // It returns the number of bytes written and an error, if any. |
| // WriteAt returns a non-nil error when n != len(b). |
| // |
| // If file was opened with the O_APPEND flag, WriteAt returns an error. |
| func (f *File) WriteAt(b []byte, off int64) (n int, err error) { |
| if err := f.checkValid("write"); err != nil { |
| return 0, err |
| } |
| if f.appendMode { |
| return 0, errWriteAtInAppendMode |
| } |
| |
| if off < 0 { |
| return 0, &PathError{Op: "writeat", Path: f.name, Err: errors.New("negative offset")} |
| } |
| |
| for len(b) > 0 { |
| m, e := f.pwrite(b, off) |
| if e != nil { |
| err = f.wrapErr("write", e) |
| break |
| } |
| n += m |
| b = b[m:] |
| off += int64(m) |
| } |
| return |
| } |
| |
| // Seek sets the offset for the next Read or Write on file to offset, interpreted |
| // according to whence: 0 means relative to the origin of the file, 1 means |
| // relative to the current offset, and 2 means relative to the end. |
| // It returns the new offset and an error, if any. |
| // The behavior of Seek on a file opened with O_APPEND is not specified. |
| // |
| // If f is a directory, the behavior of Seek varies by operating |
| // system; you can seek to the beginning of the directory on Unix-like |
| // operating systems, but not on Windows. |
| func (f *File) Seek(offset int64, whence int) (ret int64, err error) { |
| if err := f.checkValid("seek"); err != nil { |
| return 0, err |
| } |
| r, e := f.seek(offset, whence) |
| if e == nil && f.dirinfo != nil && r != 0 { |
| e = syscall.EISDIR |
| } |
| if e != nil { |
| return 0, f.wrapErr("seek", e) |
| } |
| return r, nil |
| } |
| |
| // WriteString is like Write, but writes the contents of string s rather than |
| // a slice of bytes. |
| func (f *File) WriteString(s string) (n int, err error) { |
| var b []byte |
| hdr := (*unsafeheader.Slice)(unsafe.Pointer(&b)) |
| hdr.Data = (*unsafeheader.String)(unsafe.Pointer(&s)).Data |
| hdr.Cap = len(s) |
| hdr.Len = len(s) |
| return f.Write(b) |
| } |
| |
| // Mkdir creates a new directory with the specified name and permission |
| // bits (before umask). |
| // If there is an error, it will be of type *PathError. |
| func Mkdir(name string, perm FileMode) error { |
| if runtime.GOOS == "windows" && isWindowsNulName(name) { |
| return &PathError{Op: "mkdir", Path: name, Err: syscall.ENOTDIR} |
| } |
| longName := fixLongPath(name) |
| e := ignoringEINTR(func() error { |
| return syscall.Mkdir(longName, syscallMode(perm)) |
| }) |
| |
| if e != nil { |
| return &PathError{Op: "mkdir", Path: name, Err: e} |
| } |
| |
| // mkdir(2) itself won't handle the sticky bit on *BSD and Solaris |
| if !supportsCreateWithStickyBit && perm&ModeSticky != 0 { |
| e = setStickyBit(name) |
| |
| if e != nil { |
| Remove(name) |
| return e |
| } |
| } |
| |
| return nil |
| } |
| |
| // setStickyBit adds ModeSticky to the permission bits of path, non atomic. |
| func setStickyBit(name string) error { |
| fi, err := Stat(name) |
| if err != nil { |
| return err |
| } |
| return Chmod(name, fi.Mode()|ModeSticky) |
| } |
| |
| // Chdir changes the current working directory to the named directory. |
| // If there is an error, it will be of type *PathError. |
| func Chdir(dir string) error { |
| if e := syscall.Chdir(dir); e != nil { |
| testlog.Open(dir) // observe likely non-existent directory |
| return &PathError{Op: "chdir", Path: dir, Err: e} |
| } |
| if log := testlog.Logger(); log != nil { |
| wd, err := Getwd() |
| if err == nil { |
| log.Chdir(wd) |
| } |
| } |
| return nil |
| } |
| |
| // Open opens the named file for reading. If successful, methods on |
| // the returned file can be used for reading; the associated file |
| // descriptor has mode O_RDONLY. |
| // If there is an error, it will be of type *PathError. |
| func Open(name string) (*File, error) { |
| return OpenFile(name, O_RDONLY, 0) |
| } |
| |
| // Create creates or truncates the named file. If the file already exists, |
| // it is truncated. If the file does not exist, it is created with mode 0666 |
| // (before umask). If successful, methods on the returned File can |
| // be used for I/O; the associated file descriptor has mode O_RDWR. |
| // If there is an error, it will be of type *PathError. |
| func Create(name string) (*File, error) { |
| return OpenFile(name, O_RDWR|O_CREATE|O_TRUNC, 0666) |
| } |
| |
| // OpenFile is the generalized open call; most users will use Open |
| // or Create instead. It opens the named file with specified flag |
| // (O_RDONLY etc.). If the file does not exist, and the O_CREATE flag |
| // is passed, it is created with mode perm (before umask). If successful, |
| // methods on the returned File can be used for I/O. |
| // If there is an error, it will be of type *PathError. |
| func OpenFile(name string, flag int, perm FileMode) (*File, error) { |
| testlog.Open(name) |
| f, err := openFileNolog(name, flag, perm) |
| if err != nil { |
| return nil, err |
| } |
| f.appendMode = flag&O_APPEND != 0 |
| |
| return f, nil |
| } |
| |
| // lstat is overridden in tests. |
| var lstat = Lstat |
| |
| // Rename renames (moves) oldpath to newpath. |
| // If newpath already exists and is not a directory, Rename replaces it. |
| // OS-specific restrictions may apply when oldpath and newpath are in different directories. |
| // If there is an error, it will be of type *LinkError. |
| func Rename(oldpath, newpath string) error { |
| return rename(oldpath, newpath) |
| } |
| |
| // Many functions in package syscall return a count of -1 instead of 0. |
| // Using fixCount(call()) instead of call() corrects the count. |
| func fixCount(n int, err error) (int, error) { |
| if n < 0 { |
| n = 0 |
| } |
| return n, err |
| } |
| |
| // wrapErr wraps an error that occurred during an operation on an open file. |
| // It passes io.EOF through unchanged, otherwise converts |
| // poll.ErrFileClosing to ErrClosed and wraps the error in a PathError. |
| func (f *File) wrapErr(op string, err error) error { |
| if err == nil || err == io.EOF { |
| return err |
| } |
| if err == poll.ErrFileClosing { |
| err = ErrClosed |
| } |
| return &PathError{Op: op, Path: f.name, Err: err} |
| } |
| |
| // TempDir returns the default directory to use for temporary files. |
| // |
| // On Unix systems, it returns $TMPDIR if non-empty, else /tmp. |
| // On Windows, it uses GetTempPath, returning the first non-empty |
| // value from %TMP%, %TEMP%, %USERPROFILE%, or the Windows directory. |
| // On Plan 9, it returns /tmp. |
| // |
| // The directory is neither guaranteed to exist nor have accessible |
| // permissions. |
| func TempDir() string { |
| return tempDir() |
| } |
| |
| // UserCacheDir returns the default root directory to use for user-specific |
| // cached data. Users should create their own application-specific subdirectory |
| // within this one and use that. |
| // |
| // On Unix systems, it returns $XDG_CACHE_HOME as specified by |
| // https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html if |
| // non-empty, else $HOME/.cache. |
| // On Darwin, it returns $HOME/Library/Caches. |
| // On Windows, it returns %LocalAppData%. |
| // On Plan 9, it returns $home/lib/cache. |
| // |
| // If the location cannot be determined (for example, $HOME is not defined), |
| // then it will return an error. |
| func UserCacheDir() (string, error) { |
| var dir string |
| |
| switch runtime.GOOS { |
| case "windows": |
| dir = Getenv("LocalAppData") |
| if dir == "" { |
| return "", errors.New("%LocalAppData% is not defined") |
| } |
| |
| case "darwin", "ios": |
| dir = Getenv("HOME") |
| if dir == "" { |
| return "", errors.New("$HOME is not defined") |
| } |
| dir += "/Library/Caches" |
| |
| case "plan9": |
| dir = Getenv("home") |
| if dir == "" { |
| return "", errors.New("$home is not defined") |
| } |
| dir += "/lib/cache" |
| |
| default: // Unix |
| dir = Getenv("XDG_CACHE_HOME") |
| if dir == "" { |
| dir = Getenv("HOME") |
| if dir == "" { |
| return "", errors.New("neither $XDG_CACHE_HOME nor $HOME are defined") |
| } |
| dir += "/.cache" |
| } |
| } |
| |
| return dir, nil |
| } |
| |
| // UserConfigDir returns the default root directory to use for user-specific |
| // configuration data. Users should create their own application-specific |
| // subdirectory within this one and use that. |
| // |
| // On Unix systems, it returns $XDG_CONFIG_HOME as specified by |
| // https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html if |
| // non-empty, else $HOME/.config. |
| // On Darwin, it returns $HOME/Library/Application Support. |
| // On Windows, it returns %AppData%. |
| // On Plan 9, it returns $home/lib. |
| // |
| // If the location cannot be determined (for example, $HOME is not defined), |
| // then it will return an error. |
| func UserConfigDir() (string, error) { |
| var dir string |
| |
| switch runtime.GOOS { |
| case "windows": |
| dir = Getenv("AppData") |
| if dir == "" { |
| return "", errors.New("%AppData% is not defined") |
| } |
| |
| case "darwin", "ios": |
| dir = Getenv("HOME") |
| if dir == "" { |
| return "", errors.New("$HOME is not defined") |
| } |
| dir += "/Library/Application Support" |
| |
| case "plan9": |
| dir = Getenv("home") |
| if dir == "" { |
| return "", errors.New("$home is not defined") |
| } |
| dir += "/lib" |
| |
| default: // Unix |
| dir = Getenv("XDG_CONFIG_HOME") |
| if dir == "" { |
| dir = Getenv("HOME") |
| if dir == "" { |
| return "", errors.New("neither $XDG_CONFIG_HOME nor $HOME are defined") |
| } |
| dir += "/.config" |
| } |
| } |
| |
| return dir, nil |
| } |
| |
| // UserHomeDir returns the current user's home directory. |
| // |
| // On Unix, including macOS, it returns the $HOME environment variable. |
| // On Windows, it returns %USERPROFILE%. |
| // On Plan 9, it returns the $home environment variable. |
| func UserHomeDir() (string, error) { |
| env, enverr := "HOME", "$HOME" |
| switch runtime.GOOS { |
| case "windows": |
| env, enverr = "USERPROFILE", "%userprofile%" |
| case "plan9": |
| env, enverr = "home", "$home" |
| } |
| if v := Getenv(env); v != "" { |
| return v, nil |
| } |
| // On some geese the home directory is not always defined. |
| switch runtime.GOOS { |
| case "android": |
| return "/sdcard", nil |
| case "ios": |
| return "/", nil |
| } |
| return "", errors.New(enverr + " is not defined") |
| } |
| |
| // Chmod changes the mode of the named file to mode. |
| // If the file is a symbolic link, it changes the mode of the link's target. |
| // If there is an error, it will be of type *PathError. |
| // |
| // A different subset of the mode bits are used, depending on the |
| // operating system. |
| // |
| // On Unix, the mode's permission bits, ModeSetuid, ModeSetgid, and |
| // ModeSticky are used. |
| // |
| // On Windows, only the 0200 bit (owner writable) of mode is used; it |
| // controls whether the file's read-only attribute is set or cleared. |
| // The other bits are currently unused. For compatibility with Go 1.12 |
| // and earlier, use a non-zero mode. Use mode 0400 for a read-only |
| // file and 0600 for a readable+writable file. |
| // |
| // On Plan 9, the mode's permission bits, ModeAppend, ModeExclusive, |
| // and ModeTemporary are used. |
| func Chmod(name string, mode FileMode) error { return chmod(name, mode) } |
| |
| // Chmod changes the mode of the file to mode. |
| // If there is an error, it will be of type *PathError. |
| func (f *File) Chmod(mode FileMode) error { return f.chmod(mode) } |
| |
| // SetDeadline sets the read and write deadlines for a File. |
| // It is equivalent to calling both SetReadDeadline and SetWriteDeadline. |
| // |
| // Only some kinds of files support setting a deadline. Calls to SetDeadline |
| // for files that do not support deadlines will return ErrNoDeadline. |
| // On most systems ordinary files do not support deadlines, but pipes do. |
| // |
| // A deadline is an absolute time after which I/O operations fail with an |
| // error instead of blocking. The deadline applies to all future and pending |
| // I/O, not just the immediately following call to Read or Write. |
| // After a deadline has been exceeded, the connection can be refreshed |
| // by setting a deadline in the future. |
| // |
| // If the deadline is exceeded a call to Read or Write or to other I/O |
| // methods will return an error that wraps ErrDeadlineExceeded. |
| // This can be tested using errors.Is(err, os.ErrDeadlineExceeded). |
| // That error implements the Timeout method, and calling the Timeout |
| // method will return true, but there are other possible errors for which |
| // the Timeout will return true even if the deadline has not been exceeded. |
| // |
| // An idle timeout can be implemented by repeatedly extending |
| // the deadline after successful Read or Write calls. |
| // |
| // A zero value for t means I/O operations will not time out. |
| func (f *File) SetDeadline(t time.Time) error { |
| return f.setDeadline(t) |
| } |
| |
| // SetReadDeadline sets the deadline for future Read calls and any |
| // currently-blocked Read call. |
| // A zero value for t means Read will not time out. |
| // Not all files support setting deadlines; see SetDeadline. |
| func (f *File) SetReadDeadline(t time.Time) error { |
| return f.setReadDeadline(t) |
| } |
| |
| // SetWriteDeadline sets the deadline for any future Write calls and any |
| // currently-blocked Write call. |
| // Even if Write times out, it may return n > 0, indicating that |
| // some of the data was successfully written. |
| // A zero value for t means Write will not time out. |
| // Not all files support setting deadlines; see SetDeadline. |
| func (f *File) SetWriteDeadline(t time.Time) error { |
| return f.setWriteDeadline(t) |
| } |
| |
| // SyscallConn returns a raw file. |
| // This implements the syscall.Conn interface. |
| func (f *File) SyscallConn() (syscall.RawConn, error) { |
| if err := f.checkValid("SyscallConn"); err != nil { |
| return nil, err |
| } |
| return newRawConn(f) |
| } |
| |
| // isWindowsNulName reports whether name is os.DevNull ('NUL') on Windows. |
| // True is returned if name is 'NUL' whatever the case. |
| func isWindowsNulName(name string) bool { |
| if len(name) != 3 { |
| return false |
| } |
| if name[0] != 'n' && name[0] != 'N' { |
| return false |
| } |
| if name[1] != 'u' && name[1] != 'U' { |
| return false |
| } |
| if name[2] != 'l' && name[2] != 'L' { |
| return false |
| } |
| return true |
| } |
| |
| // DirFS returns a file system (an fs.FS) for the tree of files rooted at the directory dir. |
| // |
| // Note that DirFS("/prefix") only guarantees that the Open calls it makes to the |
| // operating system will begin with "/prefix": DirFS("/prefix").Open("file") is the |
| // same as os.Open("/prefix/file"). So if /prefix/file is a symbolic link pointing outside |
| // the /prefix tree, then using DirFS does not stop the access any more than using |
| // os.Open does. DirFS is therefore not a general substitute for a chroot-style security |
| // mechanism when the directory tree contains arbitrary content. |
| func DirFS(dir string) fs.FS { |
| return dirFS(dir) |
| } |
| |
| func containsAny(s, chars string) bool { |
| for i := 0; i < len(s); i++ { |
| for j := 0; j < len(chars); j++ { |
| if s[i] == chars[j] { |
| return true |
| } |
| } |
| } |
| return false |
| } |
| |
| type dirFS string |
| |
| func (dir dirFS) Open(name string) (fs.File, error) { |
| if !fs.ValidPath(name) || runtime.GOOS == "windows" && containsAny(name, `\:`) { |
| return nil, &PathError{Op: "open", Path: name, Err: ErrInvalid} |
| } |
| f, err := Open(string(dir) + "/" + name) |
| if err != nil { |
| return nil, err // nil fs.File |
| } |
| return f, nil |
| } |
| |
| func (dir dirFS) Stat(name string) (fs.FileInfo, error) { |
| if !fs.ValidPath(name) || runtime.GOOS == "windows" && containsAny(name, `\:`) { |
| return nil, &PathError{Op: "stat", Path: name, Err: ErrInvalid} |
| } |
| f, err := Stat(string(dir) + "/" + name) |
| if err != nil { |
| return nil, err |
| } |
| return f, nil |
| } |
| |
| // ReadFile reads the named file and returns the contents. |
| // A successful call returns err == nil, not err == EOF. |
| // Because ReadFile reads the whole file, it does not treat an EOF from Read |
| // as an error to be reported. |
| func ReadFile(name string) ([]byte, error) { |
| f, err := Open(name) |
| if err != nil { |
| return nil, err |
| } |
| defer f.Close() |
| |
| var size int |
| if info, err := f.Stat(); err == nil { |
| size64 := info.Size() |
| if int64(int(size64)) == size64 { |
| size = int(size64) |
| } |
| } |
| size++ // one byte for final read at EOF |
| |
| // If a file claims a small size, read at least 512 bytes. |
| // In particular, files in Linux's /proc claim size 0 but |
| // then do not work right if read in small pieces, |
| // so an initial read of 1 byte would not work correctly. |
| if size < 512 { |
| size = 512 |
| } |
| |
| data := make([]byte, 0, size) |
| for { |
| if len(data) >= cap(data) { |
| d := append(data[:cap(data)], 0) |
| data = d[:len(data)] |
| } |
| n, err := f.Read(data[len(data):cap(data)]) |
| data = data[:len(data)+n] |
| if err != nil { |
| if err == io.EOF { |
| err = nil |
| } |
| return data, err |
| } |
| } |
| } |
| |
| // WriteFile writes data to the named file, creating it if necessary. |
| // If the file does not exist, WriteFile creates it with permissions perm (before umask); |
| // otherwise WriteFile truncates it before writing, without changing permissions. |
| func WriteFile(name string, data []byte, perm FileMode) error { |
| f, err := OpenFile(name, O_WRONLY|O_CREATE|O_TRUNC, perm) |
| if err != nil { |
| return err |
| } |
| _, err = f.Write(data) |
| if err1 := f.Close(); err1 != nil && err == nil { |
| err = err1 |
| } |
| return err |
| } |