purego: check for nil callback (#126)

It was possible to create a C callback for a nil function but this shouldn't be possible. This commit makes it so that NewCallback will panic on a nil function.

commit: c3a82d74994b67409e9fd97be97c819977b894e9
author: TotallyGamerJet · 3y ago · 2023-04-10 13:44 UTC
committer: GitHub · 3y ago · 2023-04-10 13:44 UTC
parent: e145907
signature: GPG Unverified4AEE18F83AFDEB23 The key is unknown

1 file · +9 -4

M syscall_sysv.go +9 -4


@@ -22,9 +22,11 @@ type syscall9Args struct {
22	22
23	23		//go:nosplit
24	24		func syscall_syscall9X(fn, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2, err uintptr) {
25		-	args := syscall9Args{fn, a1, a2, a3, a4, a5, a6, a7, a8, a9,
	25	+	args := syscall9Args{
	26	+	fn, a1, a2, a3, a4, a5, a6, a7, a8, a9,
26	27		a1, a2, a3, a4, a5, a6, a7, a8,
27		-	r1, r2, err}
	28	+	r1, r2, err,
	29	+	}
28	30		runtime_cgocall(syscall9XABI0, unsafe.Pointer(&args))
29	31		return args.r1, args.r2, args.err
30	32		}

@@ -73,7 +75,10 @@ type callbackArgs struct {
73	75		func compileCallback(fn interface{}) uintptr {
74	76		val := reflect.ValueOf(fn)
75	77		if val.Kind() != reflect.Func {
76		-	panic("purego: type is not a function")
	78	+	panic("purego: the type must be a function but was not")
	79	+	}
	80	+	if val.IsNil() {
	81	+	panic("purego: function must not be nil")
77	82		}
78	83		ty := val.Type()
79	84		for i := 0; i < ty.NumIn(); i++ {

@@ -134,7 +139,7 @@ func callbackWrap(a *callbackArgs) {
134	139		var intsN int // intsN represents the number of integer arguments processed
135	140		// stack points to the index into frame of the current stack element.
136	141		// The stack begins after the float and integer registers.
137		-	var stack = numOfIntegerRegisters() + numOfFloats
	142	+	stack := numOfIntegerRegisters() + numOfFloats
138	143		for i := range args {
139	144		var pos int
140	145		switch fnType.In(i).Kind() {

 //go:nosplit
 func syscall_syscall9X(fn, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2, err uintptr) {
-	args := syscall9Args{fn, a1, a2, a3, a4, a5, a6, a7, a8, a9,
+	args := syscall9Args{
+		fn, a1, a2, a3, a4, a5, a6, a7, a8, a9,
 		a1, a2, a3, a4, a5, a6, a7, a8,
-		r1, r2, err}
+		r1, r2, err,
+	}
 	runtime_cgocall(syscall9XABI0, unsafe.Pointer(&args))
 	return args.r1, args.r2, args.err
 }
 func compileCallback(fn interface{}) uintptr {
 	val := reflect.ValueOf(fn)
 	if val.Kind() != reflect.Func {
-		panic("purego: type is not a function")
+		panic("purego: the type must be a function but was not")
+	}
+	if val.IsNil() {
+		panic("purego: function must not be nil")
 	}
 	ty := val.Type()
 	for i := 0; i < ty.NumIn(); i++ {
 	var intsN int   // intsN represents the number of integer arguments processed
 	// stack points to the index into frame of the current stack element.
 	// The stack begins after the float and integer registers.
-	var stack = numOfIntegerRegisters() + numOfFloats
+	stack := numOfIntegerRegisters() + numOfFloats
 	for i := range args {
 		var pos int
 		switch fnType.In(i).Kind() {