Description
Go version
go version go1.22.4 windows/amd64
Output of go env in your module/workspace:
set GO111MODULE=on
set GOARCH=amd64
set GOBIN=
set GOCACHE=C:\Users\Nathan\AppData\Local\go-build
set GOENV=C:\Users\Nathan\AppData\Roaming\go\env
set GOEXE=.exe
set GOEXPERIMENT=
set GOFLAGS=
set GOHOSTARCH=amd64
set GOHOSTOS=windows
set GOINSECURE=
set GOMODCACHE=C:\Users\Nathan\go\pkg\mod
set GONOPROXY=
set GONOSUMDB=
set GOOS=windows
set GOPATH=C:\Users\Nathan\go
set GOPRIVATE=
set GOPROXY=https://proxy.golang.org,direct
set GOROOT=C:/Program Files/Go
set GOSUMDB=sum.golang.org
set GOTMPDIR=
set GOTOOLCHAIN=auto
set GOTOOLDIR=C:\Program Files\Go\pkg\tool\windows_amd64
set GOVCS=
set GOVERSION=go1.22.4
set GCCGO=gccgo
set GOAMD64=v1
set AR=ar
set CC=gcc
set CXX=g++
set CGO_ENABLED=0
set GOMOD=C:\Users\Nathan\Downloads\battest\go.mod
set GOWORK=
set CGO_CFLAGS=-O2 -g
set CGO_CPPFLAGS=
set CGO_CXXFLAGS=-O2 -g
set CGO_FFLAGS=-O2 -g
set CGO_LDFLAGS=-O2 -g
set PKG_CONFIG=pkg-config
set GOGCCFLAGS=-m64 -fno-caret-diagnostics -Qunused-arguments -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=C:\Users\Nathan\AppData\Local\Temp\go-build2629603369=/tmp/go-build -gno-record-gcc-switchesWhat did you do?
I'm trying to run a go executable with problematic arguments, eg.
go run test.go "a<b" "hello world"
Under the hood this will forward the arguments to a file called test.bat, and print the arguments.
This is what the files look like:
test.go:
package main
import (
"os"
"os/exec"
)
func main() {
cmd := exec.Command("C:\\Windows\\System32\\cmd.exe", append([]string{"/C", ".\\test.bat"}, os.Args[1:]...)...)
cmd.Dir = "C:\\Users\\Nathan\\Downloads\\battest"
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
err := cmd.Run()
if err != nil {
panic(err)
}
}
test.bat:
@echo %*
What did you see happen?
$ go run test_issue.go "a<b" "hello world"
The system cannot find the file specified.
panic: exit status 1
What did you expect to see?
$ go run test.go "a<b" "hello world"
"a<b" "hello world"
Through debugging I found that the issue is down to the appendEscapeArg function in exec_windows.go under the syscall package. This function will add quotes around arguments that have spaces or tabs, but it doesn't look for any other characters that need escaping.
I noticed you can override the commandLine that syscall is served and bypass this function, and so I copied and tweaked the relevant code to also escape arguments that contain <, or >. Now it works as expected.
I'd open a PR, but I don't know enough about windows, particularly; are there other characters that need escaping?
Here's my fix for what it's worth:
package main
import (
"os"
"os/exec"
"syscall"
)
func main() {
cmd := exec.Command("C:\\Windows\\System32\\cmd.exe", append([]string{"/C", ".\\test.bat"}, os.Args[1:]...)...)
cmd.SysProcAttr = &syscall.SysProcAttr{CmdLine: makeCmdLine(cmd.Args)}
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
err := cmd.Run()
if err != nil {
panic(err)
}
}
// makeCmdLine builds a command line out of args by escaping "special"
// characters and joining the arguments with spaces.
func makeCmdLine(args []string) string {
var b []byte
for _, v := range args {
if len(b) > 0 {
b = append(b, ' ')
}
b = appendEscapeArg(b, v)
}
return string(b)
}
// appendEscapeArg escapes the string s, as per escapeArg,
// appends the result to b, and returns the updated slice.
func appendEscapeArg(b []byte, s string) []byte {
if len(s) == 0 {
return append(b, `""`...)
}
needsBackslash := false
needsQuotes := false
for i := 0; i < len(s); i++ {
switch s[i] {
case '"', '\\':
needsBackslash = true
case ' ', '\t', '<', '>':
needsQuotes = true
}
}
if !needsBackslash && !needsQuotes {
// No special handling required; normal case.
return append(b, s...)
}
if !needsBackslash {
// hasSpace is true, so we need to quote the string.
b = append(b, '"')
b = append(b, s...)
return append(b, '"')
}
if needsQuotes {
b = append(b, '"')
}
slashes := 0
for i := 0; i < len(s); i++ {
c := s[i]
switch c {
default:
slashes = 0
case '\\':
slashes++
case '"':
for ; slashes > 0; slashes-- {
b = append(b, '\\')
}
b = append(b, '\\')
}
b = append(b, c)
}
if needsQuotes {
for ; slashes > 0; slashes-- {
b = append(b, '\\')
}
b = append(b, '"')
}
return b
}
The above is identical to the native implementation, except that it renames hasSpace to needsQuotes and adds , '<', '>' to the needsQuotes switch case.