allow overriding qemu binary ($QEMU_SYSTEM_X86_64, $QEMU_SYSTEM_AARCH64)

Passing args is also possible (only for debugging purpose), e.g., "QEMU_SYSTEM_X86_64=/opt/qemu/bin/qemu-system-x86_64 -snapshot" .

Signed-off-by: Akihiro Suda <[email protected]>

Author: AkihiroSuda

docs/internal.md

@@ -59,6 +59,12 @@ The directory contains the following files:
 - `$LIMA_INSTANCE`: `lima ...` is expanded to `limactl shell ${LIMA_INSTANCE} ...`.
   - Default : `default`
 
+- `$QEMU_SYSTEM_X86_64`: path of `qemu-system-x86_64`
+  - Default: `qemu-system-x86_64` in `$PATH`
+
+- `$QEMU_SYSTEM_AARCH64`: path of `qemu-system-aarch64`
+  - Default: `qemu-system-aarch64` in `$PATH`
+
 ## `cidata.iso`
 `cidata.iso` contains the following files:
 

go.mod

@@ -14,6 +14,7 @@ require (
 	github.com/gorilla/mux v1.8.0
 	github.com/hashicorp/go-multierror v1.1.1
 	github.com/mattn/go-isatty v0.0.13
+	github.com/mattn/go-shellwords v1.0.12
 	github.com/norouter/norouter v0.6.3
 	github.com/nxadm/tail v1.4.8
 	github.com/pkg/errors v0.9.1

go.sum

@@ -496,6 +496,8 @@ github.com/mattn/go-isatty v0.0.13 h1:qdl+GuBjcsKKDco5BsxPJlId98mSWNKqYA+Co0SC1y
 github.com/mattn/go-isatty v0.0.13/go.mod h1:cbi8OIDigv2wuxKPP5vlRcQ1OAZbq2CE4Kysco4FUpU=
 github.com/mattn/go-runewidth v0.0.2/go.mod h1:LwmH8dsx7+W8Uxz3IHJYH5QSwggIsqBzpuz5H//U1FU=
 github.com/mattn/go-shellwords v1.0.3/go.mod h1:3xCvwCdWdlDJUrvuMn7Wuy9eWs4pE8vqg+NOMyg4B2o=
+github.com/mattn/go-shellwords v1.0.12 h1:M2zGm7EW6UQJvDeQxo4T51eKPurbeFbe8WtebGE2xrk=
+github.com/mattn/go-shellwords v1.0.12/go.mod h1:EZzvwXDESEeg03EKmM+RmDnNOPKG4lLtQsUlTZDWQ8Y=
 github.com/matttproud/golang_protobuf_extensions v1.0.1/go.mod h1:D8He9yQNgCq6Z5Ld7szi9bcBfOoFv/3dc6xSMkL2PC0=
 github.com/matttproud/golang_protobuf_extensions v1.0.2-0.20181231171920-c182affec369/go.mod h1:BSXmuO+STAnVfrANrmjBb36TMTDstsz7MSK+HVaYKv4=
 github.com/mgutz/ansi v0.0.0-20170206155736-9520e82c474b h1:j7+1HpAFS1zy5+Q4qx1fWh90gTKwiN4QCGoY9TWyyO4=

pkg/qemu/qemu.go

@@ -7,12 +7,14 @@ import (
 	"path/filepath"
 	"runtime"
 	"strconv"
+	"strings"
 
 	"github.com/AkihiroSuda/lima/pkg/downloader"
 	"github.com/AkihiroSuda/lima/pkg/iso9660util"
 	"github.com/AkihiroSuda/lima/pkg/limayaml"
 	"github.com/AkihiroSuda/lima/pkg/store/filenames"
 	"github.com/docker/go-units"
+	"github.com/mattn/go-shellwords"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
 )
@@ -83,12 +85,10 @@ func EnsureDisk(cfg Config) error {
 
 func Cmdline(cfg Config) (string, []string, error) {
 	y := cfg.LimaYAML
-	exeBase := "qemu-system-" + y.Arch
-	exe, err := exec.LookPath(exeBase)
+	exe, args, err := getExe(y.Arch)
 	if err != nil {
 		return "", nil, err
 	}
-	var args []string
 
 	// Architecture
 	accel := getAccel(y.Arch)
@@ -205,6 +205,27 @@ func Cmdline(cfg Config) (string, []string, error) {
 	return exe, args, nil
 }
 
+func getExe(arch limayaml.Arch) (string, []string, error) {
+	exeBase := "qemu-system-" + arch
+	var args []string
+	envK := "QEMU_SYSTEM_" + strings.ToUpper(arch)
+	if envV := os.Getenv(envK); envV != "" {
+		ss, err := shellwords.Parse(envV)
+		if err != nil {
+			return "", nil, errors.Wrapf(err, "failed to parse %s value %q", envK, envV)
+		}
+		exeBase, args = ss[0], ss[1:]
+		if len(args) != 0 {
+			logrus.Warnf("Specifying args (%v) via $%s is supported only for debugging!", args, envK)
+		}
+	}
+	exe, err := exec.LookPath(exeBase)
+	if err != nil {
+		return "", nil, err
+	}
+	return exe, args, nil
+}
+
 func getAccel(arch limayaml.Arch) string {
 	nativeX8664 := arch == limayaml.X8664 && runtime.GOARCH == "amd64"
 	nativeAARCH64 := arch == limayaml.AARCH64 && runtime.GOARCH == "arm64"