purego: implement dlerror & dlclose (#14)

commit: 0f3e4f83313426b50eecae8b43d626551631be62
author: TotallyGamerJet · 4y ago · 2022-08-09 00:23 UTC
committer: GitHub · 4y ago · 2022-08-09 00:23 UTC
parent: 78cdc29
signature: GPG Unverified4AEE18F83AFDEB23 The key is unknown

3 files · +46 -2

M dlfcn.go +31 -2


@@ -7,6 +7,7 @@
7	7		package purego
8	8
9	9		import (
	10	+	"reflect"
10	11		"runtime"
11	12		"unsafe"
12	13

@@ -17,8 +18,8 @@ const RTLD_GLOBAL = 0x8
17	18
18	19		const RTLD_DEFAULT = ^uintptr(1)
19	20
20		-	func Dlopen(name string, mode int) uintptr {
21		-	bs := strings.CString(name)
	21	+	func Dlopen(path string, mode int) uintptr {
	22	+	bs := strings.CString(path)
22	23		ret, _, _ := SyscallN(dlopenABI0, uintptr(unsafe.Pointer(bs)), uintptr(mode), 0)
23	24		runtime.KeepAlive(bs)
24	25		return ret

@@ -31,6 +32,34 @@ func Dlsym(handle uintptr, name string) uintptr {
31	32		return ret
32	33		}
33	34
	35	+	func Dlerror() string {
	36	+	// msg is only valid until the next call to Dlerror
	37	+	// which is why it gets copied into a Go string
	38	+	msg, _, _ := SyscallN(dlerrorABI0)
	39	+	if msg == 0 {
	40	+	return ""
	41	+	}
	42	+	var length int
	43	+	for {
	44	+	// use unsafe.Add once we reach 1.17
	45	+	if (byte)(unsafe.Pointer(msg + uintptr(length))) == '\x00' {
	46	+	break
	47	+	}
	48	+	length++
	49	+	}
	50	+	// use unsafe.Slice once we reach 1.17
	51	+	s := make([]byte, length)
	52	+	copy(s, ([]byte)(unsafe.Pointer(&reflect.SliceHeader{Data: msg, Len: length, Cap: length})))
	53	+	return string(s)
	54	+	}
	55	+
	56	+	func Dlclose(handle uintptr) bool {
	57	+	ret, _, _ := SyscallN(dlcloseABI0, handle)
	58	+	return ret != 0
	59	+	}
	60	+
34	61		// these functions exist in dlfcn_stubs.s and are calling C functions linked to in dlfcn_GOOS.go
35	62		var dlopenABI0 uintptr
36	63		var dlsymABI0 uintptr
	64	+	var dlcloseABI0 uintptr
	65	+	var dlerrorABI0 uintptr


@@ -7,6 +7,7 @@
7		package purego	7		package purego
8			8
9		import (	9		import (
			10	+	"reflect"
10		"runtime"	11		"runtime"
11		"unsafe"	12		"unsafe"
12			13

@@ -17,8 +18,8 @@ const RTLD_GLOBAL = 0x8
17			18
18		const RTLD_DEFAULT = ^uintptr(1)	19		const RTLD_DEFAULT = ^uintptr(1)
19			20
20	-	func Dlopen(name string, mode int) uintptr {	21	+	func Dlopen(path string, mode int) uintptr {
21	-	bs := strings.CString(name)	22	+	bs := strings.CString(path)
22		ret, _, _ := SyscallN(dlopenABI0, uintptr(unsafe.Pointer(bs)), uintptr(mode), 0)	23		ret, _, _ := SyscallN(dlopenABI0, uintptr(unsafe.Pointer(bs)), uintptr(mode), 0)
23		runtime.KeepAlive(bs)	24		runtime.KeepAlive(bs)
24		return ret	25		return ret

@@ -31,6 +32,34 @@ func Dlsym(handle uintptr, name string) uintptr {
31		return ret	32		return ret
32		}	33		}
33			34
			35	+	func Dlerror() string {
			36	+	// msg is only valid until the next call to Dlerror
			37	+	// which is why it gets copied into a Go string
			38	+	msg, _, _ := SyscallN(dlerrorABI0)
			39	+	if msg == 0 {
			40	+	return ""
			41	+	}
			42	+	var length int
			43	+	for {
			44	+	// use unsafe.Add once we reach 1.17
			45	+	if (byte)(unsafe.Pointer(msg + uintptr(length))) == '\x00' {
			46	+	break
			47	+	}
			48	+	length++
			49	+	}
			50	+	// use unsafe.Slice once we reach 1.17
			51	+	s := make([]byte, length)
			52	+	copy(s, ([]byte)(unsafe.Pointer(&reflect.SliceHeader{Data: msg, Len: length, Cap: length})))
			53	+	return string(s)
			54	+	}
			55	+
			56	+	func Dlclose(handle uintptr) bool {
			57	+	ret, _, _ := SyscallN(dlcloseABI0, handle)
			58	+	return ret != 0
			59	+	}
			60	+
34		// these functions exist in dlfcn_stubs.s and are calling C functions linked to in dlfcn_GOOS.go	61		// these functions exist in dlfcn_stubs.s and are calling C functions linked to in dlfcn_GOOS.go
35		var dlopenABI0 uintptr	62		var dlopenABI0 uintptr
36		var dlsymABI0 uintptr	63		var dlsymABI0 uintptr
			64	+	var dlcloseABI0 uintptr
			65	+	var dlerrorABI0 uintptr

M dlfcn_darwin.go +2 -0


@@ -5,3 +5,5 @@ package purego
5	5
6	6		//go:cgo_import_dynamic _dlopen dlopen "/usr/lib/libSystem.B.dylib"
7	7		//go:cgo_import_dynamic _dlsym dlsym "/usr/lib/libSystem.B.dylib"
	8	+	//go:cgo_import_dynamic _dlerror dlerror "/usr/lib/libSystem.B.dylib"
	9	+	//go:cgo_import_dynamic _dlclose dlclose "/usr/lib/libSystem.B.dylib"


@@ -5,3 +5,5 @@ package purego
5		5
6	//go:cgo_import_dynamic _dlopen dlopen "/usr/lib/libSystem.B.dylib"	6		//go:cgo_import_dynamic _dlopen dlopen "/usr/lib/libSystem.B.dylib"
7	//go:cgo_import_dynamic _dlsym dlsym "/usr/lib/libSystem.B.dylib"	7		//go:cgo_import_dynamic _dlsym dlsym "/usr/lib/libSystem.B.dylib"
		8	+	//go:cgo_import_dynamic _dlerror dlerror "/usr/lib/libSystem.B.dylib"
		9	+	//go:cgo_import_dynamic _dlclose dlclose "/usr/lib/libSystem.B.dylib"

M dlfcn_stubs.s +13 -0


@@ -20,3 +20,16 @@ TEXT dlsym(SB), NOSPLIT, $0-0
20	20		JMP _dlsym(SB)
21	21		RET
22	22
	23	+	// func dlerror() (ret *byte)
	24	+	GLOBL ·dlerrorABI0(SB), NOPTR\|RODATA, $8
	25	+	DATA ·dlerrorABI0(SB)/8, $dlerror(SB)
	26	+	TEXT dlerror(SB), NOSPLIT, $0-0
	27	+	JMP _dlerror(SB)
	28	+	RET
	29	+
	30	+	// func dlclose(handle uintptr) (ret int)
	31	+	GLOBL ·dlcloseABI0(SB), NOPTR\|RODATA, $8
	32	+	DATA ·dlcloseABI0(SB)/8, $dlclose(SB)
	33	+	TEXT dlclose(SB), NOSPLIT, $0-0
	34	+	JMP _dlclose(SB)
	35	+	RET


@@ -20,3 +20,16 @@ TEXT dlsym(SB), NOSPLIT, $0-0
20	JMP _dlsym(SB)	20		JMP _dlsym(SB)
21	RET	21		RET
22		22
		23	+	// func dlerror() (ret *byte)
		24	+	GLOBL ·dlerrorABI0(SB), NOPTR\|RODATA, $8
		25	+	DATA ·dlerrorABI0(SB)/8, $dlerror(SB)
		26	+	TEXT dlerror(SB), NOSPLIT, $0-0
		27	+	JMP _dlerror(SB)
		28	+	RET
		29	+
		30	+	// func dlclose(handle uintptr) (ret int)
		31	+	GLOBL ·dlcloseABI0(SB), NOPTR\|RODATA, $8
		32	+	DATA ·dlcloseABI0(SB)/8, $dlclose(SB)
		33	+	TEXT dlclose(SB), NOSPLIT, $0-0
		34	+	JMP _dlclose(SB)
		35	+	RET