cmd/bpf2go: read more flags from environment

Signed-off-by: Puqns67 <me@puqns67.icu>

cmd/bpf2go/main.go

@@ -124,13 +124,15 @@ func newB2G(stdout io.Writer, pkg, outputDir string, args []string) (*bpf2go, er
 	fs := flag.NewFlagSet("bpf2go", flag.ContinueOnError)
 	fs.StringVar(&b2g.cc, "cc", getEnv("BPF2GO_CC", "clang"),
 		"`binary` used to compile C to BPF ($BPF2GO_CC)")
-	fs.StringVar(&b2g.strip, "strip", getEnv("BPF2GO_STRIP", ""),
+	fs.StringVar(&b2g.strip, "strip", getEnv("BPF2GO_STRIP", "llvm-strip"),
 		"`binary` used to strip DWARF from compiled BPF ($BPF2GO_STRIP)")
-	fs.BoolVar(&b2g.disableStripping, "no-strip", false, "disable stripping of DWARF")
+	fs.BoolVar(&b2g.disableStripping, "no-strip", getBoolEnv("BPF2GO_NOSTRIP", false),
+		"disable stripping of DWARF ($BPF2GO_NOSTRIP)")
 	flagCFlags := fs.String("cflags", getEnv("BPF2GO_CFLAGS", ""),
 		"flags passed to the compiler, may contain quoted arguments ($BPF2GO_CFLAGS)")
 	fs.Var(&b2g.tags, "tags", "Comma-separated list of Go build tags to include in generated files")
-	flagTarget := fs.String("target", "bpfel,bpfeb", "clang target(s) to compile for (comma separated)")
+	flagTarget := fs.String("target", getEnv("BPF2GO_TARGET", "bpfel,bpfeb"),
+		"clang target(s) to compile for (comma separated) ($BPF2GO_TARGET)")
 	fs.StringVar(&b2g.makeBase, "makebase", getEnv("BPF2GO_MAKEBASE", ""),
 		"write make compatible depinfo files relative to `directory` ($BPF2GO_MAKEBASE)")
 	fs.Var(&b2g.cTypes, "type", "`Name` of a type to generate a Go declaration for, may be repeated")
@@ -218,15 +220,6 @@ func newB2G(stdout io.Writer, pkg, outputDir string, args []string) (*bpf2go, er
 	}
 	b2g.targetArches = targetArches
 
-	// Try to find a suitable llvm-strip, possibly with a version suffix derived
-	// from the clang binary.
-	if b2g.strip == "" {
-		b2g.strip = "llvm-strip"
-		if strings.HasPrefix(b2g.cc, "clang") {
-			b2g.strip += strings.TrimPrefix(b2g.cc, "clang")
-		}
-	}
-
 	return b2g, nil
 }
 
@@ -275,6 +268,15 @@ func getEnv(key, defaultVal string) string {
 	return defaultVal
 }
 
+func getBoolEnv(key string, defaultVal bool) bool {
+	val, ok := os.LookupEnv(key)
+	if !ok {
+		return defaultVal
+	}
+	val = strings.ToLower(val)
+	return val == "true" || val == "yes" || val == "y" || val == "1"
+}
+
 func (b2g *bpf2go) convertAll() (err error) {
 	if _, err := os.Stat(b2g.sourceFile); os.IsNotExist(err) {
 		return fmt.Errorf("file %s doesn't exist", b2g.sourceFile)
@@ -283,8 +285,13 @@ func (b2g *bpf2go) convertAll() (err error) {
 	}
 
 	if !b2g.disableStripping {
-		b2g.strip, err = exec.LookPath(b2g.strip)
-		if err != nil {
+		// Try to find a suitable llvm-strip, possibly with a version suffix derived
+		// from the clang binary.
+		if b2g.strip == "llvm-strip" && strings.HasPrefix(b2g.cc, "clang") {
+			b2g.strip += strings.TrimPrefix(b2g.cc, "clang")
+		}
+
+		if b2g.strip, err = exec.LookPath(b2g.strip); err != nil {
 			return err
 		}
 	}