// 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.
// Fork, exec, wait, etc.
package windows
import (
errorspkg "errors"
"unsafe"
)
// EscapeArg rewrites command line argument s as prescribed
// in http://msdn.microsoft.com/en-us/library/ms880421.
// This function returns "" (2 double quotes) if s is empty.
// Alternatively, these transformations are done:
// - every back slash (\) is doubled, but only if immediately
// followed by double quote (");
// - every double quote (") is escaped by back slash (\);
// - finally, s is wrapped with double quotes (arg -> "arg"),
// but only if there is space or tab inside s.
func EscapeArg(s string) string {
if len(s) == 0 {
return `""`
}
n := len(s)
hasSpace := false
for i := 0; i < len(s); i++ {
switch s[i] {
case '"', '\\':
n++
case ' ', '\t':
hasSpace = true
}
}
if hasSpace {
n += 2 // Reserve space for quotes.
}
if n == len(s) {
return s
}
qs := make([]byte, n)
j := 0
if hasSpace {
qs[j] = '"'
j++
}
slashes := 0
for i := 0; i < len(s); i++ {
switch s[i] {
default:
slashes = 0
qs[j] = s[i]
case '\\':
slashes++
qs[j] = s[i]
case '"':
for ; slashes > 0; slashes-- {
qs[j] = '\\'
j++
}
qs[j] = '\\'
j++
qs[j] = s[i]
}
j++
}
if hasSpace {
for ; slashes > 0; slashes-- {
qs[j] = '\\'
j++
}
qs[j] = '"'
j++
}
return string(qs[:j])
}
// ComposeCommandLine escapes and joins the given arguments suitable for use as a Windows command line,
// in CreateProcess's CommandLine argument, CreateService/ChangeServiceConfig's BinaryPathName argument,
// or any program that uses CommandLineToArgv.
func ComposeCommandLine(args []string) string {
if len(args) == 0 {
return ""
}
// Per https://learn.microsoft.com/en-us/windows/win32/api/shellapi/nf-shellapi-commandlinetoargvw:
// “This function accepts command lines that contain a program name; the
// program name can be enclosed in quotation marks or not.”
//
// Unfortunately, it provides no means of escaping interior quotation marks
// within that program name, and we have no way to report them here.
prog := args[0]
mustQuote := len(prog) == 0
for i := 0; i < len(prog); i++ {
c := prog[i]
if c <= ' ' || (c == '"' && i == 0) {
// Force quotes for not only the ASCII space and tab as described in the
// MSDN article, but also ASCII control characters.
// The documentation for CommandLineToArgvW doesn't say what happens when
// the first argument is not a valid program name, but it empirically
// seems to drop unquoted control characters.
mustQuote = true
break
}
}
var commandLine []byte
if mustQuote {
commandLine = make([]byte, 0, len(prog)+2)
commandLine = append(commandLine, '"')
for i := 0; i < len(prog); i++ {
c := prog[i]
if c == '"' {
// This quote would interfere with our surrounding quotes.
// We have no way to report an error, so just strip out
// the offending character instead.
continue
}
commandLine = append(commandLine, c)
}
commandLine = append(commandLine, '"')
} else {
if len(args) == 1 {
// args[0] is a valid command line representing itself.
// No need to allocate a new slice or string for it.
return prog
}
commandLine = []byte(prog)
}
for _, arg := range args[1:] {
commandLine = append(commandLine, ' ')
// TODO(bcmills): since we're already appending to a slice, it would be nice
// to avoid the intermediate allocations of EscapeArg.
// Perhaps we can factor out an appendEscapedArg function.
commandLine = append(commandLine, EscapeArg(arg)...)
}
return string(commandLine)
}
// DecomposeCommandLine breaks apart its argument command line into unescaped parts using CommandLineToArgv,
// as gathered from GetCommandLine, QUERY_SERVICE_CONFIG's BinaryPathName argument, or elsewhere that
// command lines are passed around.
// DecomposeCommandLine returns an error if commandLine contains NUL.
func DecomposeCommandLine(commandLine string) ([]string, error) {
if len(commandLine) == 0 {
return []string{}, nil
}
utf16CommandLine, err := UTF16FromString(commandLine)
if err != nil {
return nil, errorspkg.New("string with NUL passed to DecomposeCommandLine")
}
var argc int32
argv, err := commandLineToArgv(&utf16CommandLine[0], &argc)
if err != nil {
return nil, err
}
defer LocalFree(Handle(unsafe.Pointer(argv)))
var args []string
for _, p := range unsafe.Slice(argv, argc) {
args = append(args, UTF16PtrToString(p))
}
return args, nil
}
// CommandLineToArgv parses a Unicode command line string and sets
// argc to the number of parsed arguments.
//
// The returned memory should be freed using a single call to LocalFree.
//
// Note that although the return type of CommandLineToArgv indicates 8192
// entries of up to 8192 characters each, the actual count of parsed arguments
// may exceed 8192, and the documentation for CommandLineToArgvW does not mention
// any bound on the lengths of the individual argument strings.
// (See https://go.dev/issue/63236.)
func CommandLineToArgv(cmd *uint16, argc *int32) (argv *[8192]*[8192]uint16, err error) {
argp, err := commandLineToArgv(cmd, argc)
argv = (*[8192]*[8192]uint16)(unsafe.Pointer(argp))
return argv, err
}
func CloseOnExec(fd Handle) {
SetHandleInformation(Handle(fd), HANDLE_FLAG_INHERIT, 0)
}
// FullPath retrieves the full path of the specified file.
func FullPath(name string) (path string, err error) {
p, err := UTF16PtrFromString(name)
if err != nil {
return "", err
}
n := uint32(100)
for {
buf := make([]uint16, n)
n, err = GetFullPathName(p, uint32(len(buf)), &buf[0], nil)
if err != nil {
return "", err
}
if n <= uint32(len(buf)) {
return UTF16ToString(buf[:n]), nil
}
}
}
// NewProcThreadAttributeList allocates a new ProcThreadAttributeListContainer, with the requested maximum number of attributes.
func NewProcThreadAttributeList(maxAttrCount uint32) (*ProcThreadAttributeListContainer, error) {
var size uintptr
err := initializeProcThreadAttributeList(nil, maxAttrCount, 0, &size)
if err != ERROR_INSUFFICIENT_BUFFER {
if err == nil {
return nil, errorspkg.New("unable to query buffer size from InitializeProcThreadAttributeList")
}
return nil, err
}
alloc, err := LocalAlloc(LMEM_FIXED, uint32(size))
if err != nil {
return nil, err
}
// size is guaranteed to be ≥1 by InitializeProcThreadAttributeList.
al := &ProcThreadAttributeListContainer{data: (*ProcThreadAttributeList)(unsafe.Pointer(alloc))}
err = initializeProcThreadAttributeList(al.data, maxAttrCount, 0, &size)
if err != nil {
return nil, err
}
return al, err
}
// Update modifies the ProcThreadAttributeList using UpdateProcThreadAttribute.
func (al *ProcThreadAttributeListContainer) Update(attribute uintptr, value unsafe.Pointer, size uintptr) error {
al.pointers = append(al.pointers, value)
return updateProcThreadAttribute(al.data, 0, attribute, value, size, nil, nil)
}
// Delete frees ProcThreadAttributeList's resources.
func (al *ProcThreadAttributeListContainer) Delete() {
deleteProcThreadAttributeList(al.data)
LocalFree(Handle(unsafe.Pointer(al.data)))
al.data = nil
al.pointers = nil
}
// List returns the actual ProcThreadAttributeList to be passed to StartupInfoEx.
func (al *ProcThreadAttributeListContainer) List() *ProcThreadAttributeList {
return al.data
}
