limit expand env to cmd pkg-config & llvm-config

xtool/env/env.go

@@ -17,32 +17,49 @@
 package env
 
 import (
+	"fmt"
 	"os"
 	"os/exec"
 	"regexp"
-	"runtime"
 	"strings"
 )
 
+var (
+	reSubcmd = regexp.MustCompile(`\$\([^)]+\)`)
+	reFlag   = regexp.MustCompile(`[^ \t\n]+`)
+)
+
 func ExpandEnv(s string) string {
 	return expandEnvWithCmd(s)
 }
 
 func expandEnvWithCmd(s string) string {
-	re := regexp.MustCompile(`\$\(([^)]+)\)`)
+	expanded := reSubcmd.ReplaceAllStringFunc(s, func(m string) string {
-	expanded := re.ReplaceAllStringFunc(s, func(m string) string {
+		subcmd := strings.TrimSpace(s[2 : len(s)-1])
-		cmd := re.FindStringSubmatch(m)[1]
+
-		var out []byte
+		args := parseSubcmd(subcmd)
-		var err error
+
-		if runtime.GOOS == "windows" {
+		cmd := args[0]
-			out, err = exec.Command("cmd", "/C", cmd).Output()
+
-		} else {
+		if cmd != "pkg-config" && cmd != "llvm-config" {
-			out, err = exec.Command("sh", "-c", cmd).Output()
+			fmt.Fprintf(os.Stderr, "expand cmd only support pkg-config and llvm-config: '%s'\n", subcmd)
-		}
-		if err != nil {
 			return ""
 		}
-		return strings.TrimSpace(string(out))
+
+		var out []byte
+		var err error
+		out, err = exec.Command(cmd, args[1:]...).Output()
+
+		if err != nil {
+			// TODO(kindy): log in verbose mode
+			return ""
+		}
+
+		return string(out)
 	})
 	return os.Expand(expanded, os.Getenv)
 }
+
+func parseSubcmd(s string) []string {
+	return reFlag.FindAllString(s, -1)
+}