replace sys Sequential funcs with moby/sys/sequential
These functions were originally copied from the docker / moby repository in
4a7a8efc2d. Migrating these functions to use the
github.com/moby/sys/sequential module allows them being shared between moby,
docker/cli, and containerd, and to allow using them without importing all of sys
which also depends on hcsshim and more.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
			
			
This commit is contained in:
		
							
								
								
									
										202
									
								
								vendor/github.com/moby/sys/sequential/LICENSE
									
									
									
										generated
									
									
										vendored
									
									
										Normal file
									
								
							
							
						
						
									
										202
									
								
								vendor/github.com/moby/sys/sequential/LICENSE
									
									
									
										generated
									
									
										vendored
									
									
										Normal file
									
								
							@@ -0,0 +1,202 @@
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 | 
			
		||||
// Package sequential provides a set of functions for managing sequential
 | 
			
		||||
// files on Windows.
 | 
			
		||||
//
 | 
			
		||||
// The origin of these functions are the golang OS and windows packages,
 | 
			
		||||
// slightly modified to only cope with files, not directories due to the
 | 
			
		||||
// specific use case.
 | 
			
		||||
//
 | 
			
		||||
// The alteration is to allow a file on Windows to be opened with
 | 
			
		||||
// FILE_FLAG_SEQUENTIAL_SCAN (particular for docker load), to avoid eating
 | 
			
		||||
// the standby list, particularly when accessing large files such as layer.tar.
 | 
			
		||||
//
 | 
			
		||||
// For non-Windows platforms, the package provides wrappers for the equivalents
 | 
			
		||||
// in the os packages. They are passthrough on Unix platforms, and only relevant
 | 
			
		||||
// on Windows.
 | 
			
		||||
package sequential
 | 
			
		||||
							
								
								
									
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//go:build !windows
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		||||
// +build !windows
 | 
			
		||||
 | 
			
		||||
package sequential
 | 
			
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 | 
			
		||||
import "os"
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 | 
			
		||||
// Create creates the named file with mode 0666 (before umask), truncating
 | 
			
		||||
// it if it already exists. 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) (*os.File, error) {
 | 
			
		||||
	return os.Create(name)
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
// 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) (*os.File, error) {
 | 
			
		||||
	return os.Open(name)
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
// 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.) and perm, (0666 etc.) if applicable. 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 os.FileMode) (*os.File, error) {
 | 
			
		||||
	return os.OpenFile(name, flag, perm)
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
// CreateTemp creates a new temporary file in the directory dir
 | 
			
		||||
// with a name beginning with prefix, opens the file for reading
 | 
			
		||||
// and writing, and returns the resulting *os.File.
 | 
			
		||||
// If dir is the empty string, TempFile uses the default directory
 | 
			
		||||
// for temporary files (see os.TempDir).
 | 
			
		||||
// Multiple programs calling TempFile simultaneously
 | 
			
		||||
// will not choose the same file. The caller can use f.Name()
 | 
			
		||||
// to find the pathname of the file. It is the caller's responsibility
 | 
			
		||||
// to remove the file when no longer needed.
 | 
			
		||||
func CreateTemp(dir, prefix string) (f *os.File, err error) {
 | 
			
		||||
	return os.CreateTemp(dir, prefix)
 | 
			
		||||
}
 | 
			
		||||
							
								
								
									
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										161
									
								
								vendor/github.com/moby/sys/sequential/sequential_windows.go
									
									
									
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							@@ -0,0 +1,161 @@
 | 
			
		||||
package sequential
 | 
			
		||||
 | 
			
		||||
import (
 | 
			
		||||
	"os"
 | 
			
		||||
	"path/filepath"
 | 
			
		||||
	"strconv"
 | 
			
		||||
	"sync"
 | 
			
		||||
	"syscall"
 | 
			
		||||
	"time"
 | 
			
		||||
	"unsafe"
 | 
			
		||||
 | 
			
		||||
	"golang.org/x/sys/windows"
 | 
			
		||||
)
 | 
			
		||||
 | 
			
		||||
// Create creates the named file with mode 0666 (before umask), truncating
 | 
			
		||||
// it if it already exists. 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) (*os.File, error) {
 | 
			
		||||
	return OpenFile(name, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0)
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
// 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) (*os.File, error) {
 | 
			
		||||
	return OpenFile(name, os.O_RDONLY, 0)
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
// OpenFile is the generalized open call; most users will use Open
 | 
			
		||||
// or Create instead.
 | 
			
		||||
// If there is an error, it will be of type *PathError.
 | 
			
		||||
func OpenFile(name string, flag int, _ os.FileMode) (*os.File, error) {
 | 
			
		||||
	if name == "" {
 | 
			
		||||
		return nil, &os.PathError{Op: "open", Path: name, Err: syscall.ENOENT}
 | 
			
		||||
	}
 | 
			
		||||
	r, err := openFileSequential(name, flag, 0)
 | 
			
		||||
	if err == nil {
 | 
			
		||||
		return r, nil
 | 
			
		||||
	}
 | 
			
		||||
	return nil, &os.PathError{Op: "open", Path: name, Err: err}
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
func openFileSequential(name string, flag int, _ os.FileMode) (file *os.File, err error) {
 | 
			
		||||
	r, e := openSequential(name, flag|windows.O_CLOEXEC, 0)
 | 
			
		||||
	if e != nil {
 | 
			
		||||
		return nil, e
 | 
			
		||||
	}
 | 
			
		||||
	return os.NewFile(uintptr(r), name), nil
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
func makeInheritSa() *windows.SecurityAttributes {
 | 
			
		||||
	var sa windows.SecurityAttributes
 | 
			
		||||
	sa.Length = uint32(unsafe.Sizeof(sa))
 | 
			
		||||
	sa.InheritHandle = 1
 | 
			
		||||
	return &sa
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
func openSequential(path string, mode int, _ uint32) (fd windows.Handle, err error) {
 | 
			
		||||
	if len(path) == 0 {
 | 
			
		||||
		return windows.InvalidHandle, windows.ERROR_FILE_NOT_FOUND
 | 
			
		||||
	}
 | 
			
		||||
	pathp, err := windows.UTF16PtrFromString(path)
 | 
			
		||||
	if err != nil {
 | 
			
		||||
		return windows.InvalidHandle, err
 | 
			
		||||
	}
 | 
			
		||||
	var access uint32
 | 
			
		||||
	switch mode & (windows.O_RDONLY | windows.O_WRONLY | windows.O_RDWR) {
 | 
			
		||||
	case windows.O_RDONLY:
 | 
			
		||||
		access = windows.GENERIC_READ
 | 
			
		||||
	case windows.O_WRONLY:
 | 
			
		||||
		access = windows.GENERIC_WRITE
 | 
			
		||||
	case windows.O_RDWR:
 | 
			
		||||
		access = windows.GENERIC_READ | windows.GENERIC_WRITE
 | 
			
		||||
	}
 | 
			
		||||
	if mode&windows.O_CREAT != 0 {
 | 
			
		||||
		access |= windows.GENERIC_WRITE
 | 
			
		||||
	}
 | 
			
		||||
	if mode&windows.O_APPEND != 0 {
 | 
			
		||||
		access &^= windows.GENERIC_WRITE
 | 
			
		||||
		access |= windows.FILE_APPEND_DATA
 | 
			
		||||
	}
 | 
			
		||||
	sharemode := uint32(windows.FILE_SHARE_READ | windows.FILE_SHARE_WRITE)
 | 
			
		||||
	var sa *windows.SecurityAttributes
 | 
			
		||||
	if mode&windows.O_CLOEXEC == 0 {
 | 
			
		||||
		sa = makeInheritSa()
 | 
			
		||||
	}
 | 
			
		||||
	var createmode uint32
 | 
			
		||||
	switch {
 | 
			
		||||
	case mode&(windows.O_CREAT|windows.O_EXCL) == (windows.O_CREAT | windows.O_EXCL):
 | 
			
		||||
		createmode = windows.CREATE_NEW
 | 
			
		||||
	case mode&(windows.O_CREAT|windows.O_TRUNC) == (windows.O_CREAT | windows.O_TRUNC):
 | 
			
		||||
		createmode = windows.CREATE_ALWAYS
 | 
			
		||||
	case mode&windows.O_CREAT == windows.O_CREAT:
 | 
			
		||||
		createmode = windows.OPEN_ALWAYS
 | 
			
		||||
	case mode&windows.O_TRUNC == windows.O_TRUNC:
 | 
			
		||||
		createmode = windows.TRUNCATE_EXISTING
 | 
			
		||||
	default:
 | 
			
		||||
		createmode = windows.OPEN_EXISTING
 | 
			
		||||
	}
 | 
			
		||||
	// Use FILE_FLAG_SEQUENTIAL_SCAN rather than FILE_ATTRIBUTE_NORMAL as implemented in golang.
 | 
			
		||||
	// https://msdn.microsoft.com/en-us/library/windows/desktop/aa363858(v=vs.85).aspx
 | 
			
		||||
	const fileFlagSequentialScan = 0x08000000 // FILE_FLAG_SEQUENTIAL_SCAN
 | 
			
		||||
	h, e := windows.CreateFile(pathp, access, sharemode, sa, createmode, fileFlagSequentialScan, 0)
 | 
			
		||||
	return h, e
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
// Helpers for CreateTemp
 | 
			
		||||
var rand uint32
 | 
			
		||||
var randmu sync.Mutex
 | 
			
		||||
 | 
			
		||||
func reseed() uint32 {
 | 
			
		||||
	return uint32(time.Now().UnixNano() + int64(os.Getpid()))
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
func nextSuffix() string {
 | 
			
		||||
	randmu.Lock()
 | 
			
		||||
	r := rand
 | 
			
		||||
	if r == 0 {
 | 
			
		||||
		r = reseed()
 | 
			
		||||
	}
 | 
			
		||||
	r = r*1664525 + 1013904223 // constants from Numerical Recipes
 | 
			
		||||
	rand = r
 | 
			
		||||
	randmu.Unlock()
 | 
			
		||||
	return strconv.Itoa(int(1e9 + r%1e9))[1:]
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
// CreateTemp is a copy of os.CreateTemp, modified to use sequential
 | 
			
		||||
// file access. Below is the original comment from golang:
 | 
			
		||||
// TempFile creates a new temporary file in the directory dir
 | 
			
		||||
// with a name beginning with prefix, opens the file for reading
 | 
			
		||||
// and writing, and returns the resulting *os.File.
 | 
			
		||||
// If dir is the empty string, TempFile uses the default directory
 | 
			
		||||
// for temporary files (see os.TempDir).
 | 
			
		||||
// Multiple programs calling TempFile simultaneously
 | 
			
		||||
// will not choose the same file. The caller can use f.Name()
 | 
			
		||||
// to find the pathname of the file. It is the caller's responsibility
 | 
			
		||||
// to remove the file when no longer needed.
 | 
			
		||||
func CreateTemp(dir, prefix string) (f *os.File, err error) {
 | 
			
		||||
	if dir == "" {
 | 
			
		||||
		dir = os.TempDir()
 | 
			
		||||
	}
 | 
			
		||||
 | 
			
		||||
	nconflict := 0
 | 
			
		||||
	for i := 0; i < 10000; i++ {
 | 
			
		||||
		name := filepath.Join(dir, prefix+nextSuffix())
 | 
			
		||||
		f, err = OpenFile(name, os.O_RDWR|os.O_CREATE|os.O_EXCL, 0o600)
 | 
			
		||||
		if os.IsExist(err) {
 | 
			
		||||
			if nconflict++; nconflict > 10 {
 | 
			
		||||
				randmu.Lock()
 | 
			
		||||
				rand = reseed()
 | 
			
		||||
				randmu.Unlock()
 | 
			
		||||
			}
 | 
			
		||||
			continue
 | 
			
		||||
		}
 | 
			
		||||
		break
 | 
			
		||||
	}
 | 
			
		||||
	return
 | 
			
		||||
}
 | 
			
		||||
		Reference in New Issue
	
	Block a user