1 // Copyright 2015 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
5 // Tests that cgo detects invalid pointer passing at runtime.
23 var tmp = flag.String("tmp", "", "use `dir` for temporary files and do not clean up")
25 // ptrTest is the tests without the boilerplate.
27 name string // for reporting
28 c string // the cgo comment
29 c1 string // cgo comment forced into non-export cgo file
30 imports []string // a list of imports
31 support string // supporting functions
32 body string // the body of the main function
33 extra []extra // extra files
34 fail bool // whether the test should fail
35 expensive bool // whether the test requires the expensive check
43 var ptrTests = []ptrTest{
45 // Passing a pointer to a struct that contains a Go pointer.
47 c: `typedef struct s1 { int *p; } s1; void f1(s1 *ps) {}`,
48 body: `C.f1(&C.s1{new(C.int)})`,
52 // Passing a pointer to a struct that contains a Go pointer.
54 c: `typedef struct s2 { int *p; } s2; void f2(s2 *ps) {}`,
55 body: `p := &C.s2{new(C.int)}; C.f2(p)`,
59 // Passing a pointer to an int field of a Go struct
60 // that (irrelevantly) contains a Go pointer.
62 c: `struct s3 { int i; int *p; }; void f3(int *p) {}`,
63 body: `p := &C.struct_s3{i: 0, p: new(C.int)}; C.f3(&p.i)`,
67 // Passing a pointer to a pointer field of a Go struct.
69 c: `struct s4 { int i; int *p; }; void f4(int **p) {}`,
70 body: `p := &C.struct_s4{i: 0, p: new(C.int)}; C.f4(&p.p)`,
74 // Passing a pointer to a pointer field of a Go
75 // struct, where the field does not contain a Go
76 // pointer, but another field (irrelevantly) does.
78 c: `struct s5 { int *p1; int *p2; }; void f5(int **p) {}`,
79 body: `p := &C.struct_s5{p1: nil, p2: new(C.int)}; C.f5(&p.p1)`,
83 // Passing the address of a slice with no Go pointers.
85 c: `void f6(void **p) {}`,
86 imports: []string{"unsafe"},
87 body: `s := []unsafe.Pointer{nil}; C.f6(&s[0])`,
91 // Passing the address of a slice with a Go pointer.
93 c: `void f7(void **p) {}`,
94 imports: []string{"unsafe"},
95 body: `i := 0; s := []unsafe.Pointer{unsafe.Pointer(&i)}; C.f7(&s[0])`,
99 // Passing the address of a slice with a Go pointer,
100 // where we are passing the address of an element that
101 // is not a Go pointer.
103 c: `void f8(void **p) {}`,
104 imports: []string{"unsafe"},
105 body: `i := 0; s := []unsafe.Pointer{nil, unsafe.Pointer(&i)}; C.f8(&s[0])`,
109 // Passing the address of a slice that is an element
110 // in a struct only looks at the slice.
112 c: `void f9(void **p) {}`,
113 imports: []string{"unsafe"},
114 support: `type S9 struct { p *int; s []unsafe.Pointer }`,
115 body: `i := 0; p := &S9{p:&i, s:[]unsafe.Pointer{nil}}; C.f9(&p.s[0])`,
119 // Passing the address of a slice of an array that is
120 // an element in a struct, with a type conversion.
122 c: `void f10(void* p) {}`,
123 imports: []string{"unsafe"},
124 support: `type S10 struct { p *int; a [4]byte }`,
125 body: `i := 0; p := &S10{p:&i}; s := p.a[:]; C.f10(unsafe.Pointer(&s[0]))`,
129 // Passing the address of a slice of an array that is
130 // an element in a struct, with a type conversion.
132 c: `typedef void* PV11; void f11(PV11 p) {}`,
133 imports: []string{"unsafe"},
134 support: `type S11 struct { p *int; a [4]byte }`,
135 body: `i := 0; p := &S11{p:&i}; C.f11(C.PV11(unsafe.Pointer(&p.a[0])))`,
139 // Passing the address of a static variable with no
140 // pointers doesn't matter.
142 c: `void f12(char** parg) {}`,
143 support: `var hello12 = [...]C.char{'h', 'e', 'l', 'l', 'o'}`,
144 body: `parg := [1]*C.char{&hello12[0]}; C.f12(&parg[0])`,
148 // Passing the address of a static variable with
149 // pointers does matter.
151 c: `void f13(char*** parg) {}`,
152 support: `var hello13 = [...]*C.char{new(C.char)}`,
153 body: `parg := [1]**C.char{&hello13[0]}; C.f13(&parg[0])`,
157 // Storing a Go pointer into C memory should fail.
159 c: `#include <stdlib.h>
160 char **f14a() { return malloc(sizeof(char*)); }
161 void f14b(char **p) {}`,
162 body: `p := C.f14a(); *p = new(C.char); C.f14b(p)`,
167 // Storing a Go pointer into C memory by assigning a
168 // large value should fail.
169 name: "barrierstruct",
170 c: `#include <stdlib.h>
171 struct s15 { char *a[10]; };
172 struct s15 *f15() { return malloc(sizeof(struct s15)); }
173 void f15b(struct s15 *p) {}`,
174 body: `p := C.f15(); p.a = [10]*C.char{new(C.char)}; C.f15b(p)`,
179 // Storing a Go pointer into C memory using a slice
181 name: "barrierslice",
182 c: `#include <stdlib.h>
183 struct s16 { char *a[10]; };
184 struct s16 *f16() { return malloc(sizeof(struct s16)); }
185 void f16b(struct s16 *p) {}`,
186 body: `p := C.f16(); copy(p.a[:], []*C.char{new(C.char)}); C.f16b(p)`,
191 // A very large value uses a GC program, which is a
192 // different code path.
193 name: "barriergcprogarray",
194 c: `#include <stdlib.h>
195 struct s17 { char *a[32769]; };
196 struct s17 *f17() { return malloc(sizeof(struct s17)); }
197 void f17b(struct s17 *p) {}`,
198 body: `p := C.f17(); p.a = [32769]*C.char{new(C.char)}; C.f17b(p)`,
203 // Similar case, with a source on the heap.
204 name: "barriergcprogarrayheap",
205 c: `#include <stdlib.h>
206 struct s18 { char *a[32769]; };
207 struct s18 *f18() { return malloc(sizeof(struct s18)); }
208 void f18b(struct s18 *p) {}
209 void f18c(void *p) {}`,
210 imports: []string{"unsafe"},
211 body: `p := C.f18(); n := &[32769]*C.char{new(C.char)}; p.a = *n; C.f18b(p); n[0] = nil; C.f18c(unsafe.Pointer(n))`,
216 // A GC program with a struct.
217 name: "barriergcprogstruct",
218 c: `#include <stdlib.h>
219 struct s19a { char *a[32769]; };
220 struct s19b { struct s19a f; };
221 struct s19b *f19() { return malloc(sizeof(struct s19b)); }
222 void f19b(struct s19b *p) {}`,
223 body: `p := C.f19(); p.f = C.struct_s19a{[32769]*C.char{new(C.char)}}; C.f19b(p)`,
228 // Similar case, with a source on the heap.
229 name: "barriergcprogstructheap",
230 c: `#include <stdlib.h>
231 struct s20a { char *a[32769]; };
232 struct s20b { struct s20a f; };
233 struct s20b *f20() { return malloc(sizeof(struct s20b)); }
234 void f20b(struct s20b *p) {}
235 void f20c(void *p) {}`,
236 imports: []string{"unsafe"},
237 body: `p := C.f20(); n := &C.struct_s20a{[32769]*C.char{new(C.char)}}; p.f = *n; C.f20b(p); n.a[0] = nil; C.f20c(unsafe.Pointer(n))`,
242 // Exported functions may not return Go pointers.
244 c: `extern unsigned char *GoFn21();`,
245 support: `//export GoFn21
246 func GoFn21() *byte { return new(byte) }`,
251 // Returning a C pointer is fine.
253 c: `#include <stdlib.h>
254 extern unsigned char *GoFn22();`,
255 support: `//export GoFn22
256 func GoFn22() *byte { return (*byte)(C.malloc(1)) }`,
260 // Passing a Go string is fine.
262 c: `#include <stddef.h>
263 typedef struct { const char *p; ptrdiff_t n; } gostring23;
264 gostring23 f23(gostring23 s) { return s; }`,
265 imports: []string{"unsafe"},
266 body: `s := "a"; r := C.f23(*(*C.gostring23)(unsafe.Pointer(&s))); if *(*string)(unsafe.Pointer(&r)) != s { panic(r) }`,
269 // Passing a slice of Go strings fails.
270 name: "passstringslice",
271 c: `void f24(void *p) {}`,
272 imports: []string{"strings", "unsafe"},
273 support: `type S24 struct { a [1]string }`,
274 body: `s := S24{a:[1]string{strings.Repeat("a", 2)}}; C.f24(unsafe.Pointer(&s.a[0]))`,
278 // Exported functions may not return strings.
280 c: `extern void f25();`,
281 imports: []string{"strings"},
282 support: `//export GoStr25
283 func GoStr25() string { return strings.Repeat("a", 2) }`,
285 c1: `#include <stddef.h>
286 typedef struct { const char *p; ptrdiff_t n; } gostring25;
287 extern gostring25 GoStr25();
288 void f25() { GoStr25(); }`,
292 // Don't check non-pointer data.
293 // Uses unsafe code to get a pointer we shouldn't check.
294 // Although we use unsafe, the uintptr represents an integer
295 // that happens to have the same representation as a pointer;
296 // that is, we are testing something that is not unsafe.
298 c: `#include <stdlib.h>
299 void f26(void* p) {}`,
300 imports: []string{"unsafe"},
301 support: `type S26 struct { p *int; a [8*8]byte; u uintptr }`,
302 body: `i := 0; p := &S26{u:uintptr(unsafe.Pointer(&i))}; q := (*S26)(C.malloc(C.size_t(unsafe.Sizeof(*p)))); *q = *p; C.f26(unsafe.Pointer(q))`,
306 // Like ptrdata1, but with a type that uses a GC program.
308 c: `#include <stdlib.h>
309 void f27(void* p) {}`,
310 imports: []string{"unsafe"},
311 support: `type S27 struct { p *int; a [32769*8]byte; q *int; u uintptr }`,
312 body: `i := 0; p := S27{u:uintptr(unsafe.Pointer(&i))}; q := (*S27)(C.malloc(C.size_t(unsafe.Sizeof(p)))); *q = p; C.f27(unsafe.Pointer(q))`,
316 // Check deferred pointers when they are used, not
317 // when the defer statement is run.
319 c: `typedef struct s28 { int *p; } s28; void f28(s28 *ps) {}`,
320 body: `p := &C.s28{}; defer C.f28(p); p.p = new(C.int)`,
324 // Check a pointer to a union if the union has any
327 c: `typedef union { char **p; unsigned long i; } u29; void f29(u29 *pu) {}`,
328 imports: []string{"unsafe"},
329 body: `var b C.char; p := &b; C.f29((*C.u29)(unsafe.Pointer(&p)))`,
333 // Don't check a pointer to a union if the union does
334 // not have any pointer fields.
335 // Like ptrdata1 above, the uintptr represents an
336 // integer that happens to have the same
337 // representation as a pointer.
339 c: `typedef union { unsigned long i; } u39; void f39(u39 *pu) {}`,
340 imports: []string{"unsafe"},
341 body: `var b C.char; p := &b; C.f39((*C.u39)(unsafe.Pointer(&p)))`,
345 // Test preemption while entering a cgo call. Issue #21306.
346 name: "preemptduringcall",
348 imports: []string{"runtime", "sync"},
349 body: `var wg sync.WaitGroup; wg.Add(100); for i := 0; i < 100; i++ { go func(i int) { for j := 0; j < 100; j++ { C.f30(); runtime.GOMAXPROCS(i) }; wg.Done() }(i) }; wg.Wait()`,
353 // Test poller deadline with cgocheck=2. Issue #23435.
355 c: `#define US31 10`,
356 imports: []string{"os", "time"},
357 body: `r, _, _ := os.Pipe(); r.SetDeadline(time.Now().Add(C.US31 * time.Microsecond))`,
361 // Test for double evaluation of channel receive.
363 c: `void f32(char** p) {}`,
364 imports: []string{"time"},
365 body: `c := make(chan []*C.char, 2); c <- make([]*C.char, 1); go func() { time.Sleep(10 * time.Second); panic("received twice from chan") }(); C.f32(&(<-c)[0]);`,
369 // Test that converting the address of a struct field
370 // to unsafe.Pointer still just checks that field.
373 c: `void f33(void* p) {}`,
374 imports: []string{"unsafe"},
375 support: `type S33 struct { p *int; a [8]byte; u uintptr }`,
376 body: `s := &S33{p: new(int)}; C.f33(unsafe.Pointer(&s.a))`,
380 // Test that converting multiple struct field
381 // addresses to unsafe.Pointer still just checks those
382 // fields. Issue #25941.
383 name: "structfield2",
384 c: `void f34(void* p, int r, void* s) {}`,
385 imports: []string{"unsafe"},
386 support: `type S34 struct { a [8]byte; p *int; b int64; }`,
387 body: `s := &S34{p: new(int)}; C.f34(unsafe.Pointer(&s.a), 32, unsafe.Pointer(&s.b))`,
391 // Test that second argument to cgoCheckPointer is
392 // evaluated when a deferred function is deferred, not
395 c: `void f35(char **pc) {}`,
396 support: `type S35a struct { s []*C.char }; type S35b struct { ps *S35a }`,
397 body: `p := &S35b{&S35a{[]*C.char{nil}}}; defer C.f35(&p.ps.s[0]); p.ps = nil`,
401 // Test that indexing into a function call still
402 // examines only the slice being indexed.
404 c: `void f36(void *p) {}`,
405 imports: []string{"bytes", "unsafe"},
406 body: `var b bytes.Buffer; b.WriteString("a"); C.f36(unsafe.Pointer(&b.Bytes()[0]))`,
410 // Test that bgsweep releasing a finalizer is OK.
412 c: `// Nothing to declare.`,
413 imports: []string{"os"},
414 support: `func open37() { os.Open(os.Args[0]) }; var G37 [][]byte`,
415 body: `for i := 0; i < 10000; i++ { G37 = append(G37, make([]byte, 4096)); if i % 100 == 0 { G37 = nil; open37() } }`,
419 // Test that converting generated struct to interface is OK.
421 c: `// Nothing to declare.`,
422 imports: []string{"reflect"},
423 support: `type MyInt38 int; func (i MyInt38) Get() int { return int(i) }; type Getter38 interface { Get() int }`,
424 body: `t := reflect.StructOf([]reflect.StructField{{Name: "MyInt38", Type: reflect.TypeOf(MyInt38(0)), Anonymous: true}}); v := reflect.New(t).Elem(); v.Interface().(Getter38).Get()`,
428 // Test that a converted address of a struct field results
429 // in a check for just that field and not the whole struct.
430 name: "structfieldcast",
431 c: `struct S40i { int i; int* p; }; void f40(struct S40i* p) {}`,
432 support: `type S40 struct { p *int; a C.struct_S40i }`,
433 body: `s := &S40{p: new(int)}; C.f40((*C.struct_S40i)(&s.a))`,
438 func TestPointerChecks(t *testing.T) {
439 testenv.MustHaveGoBuild(t)
440 testenv.MustHaveCGO(t)
441 if runtime.GOOS == "windows" {
442 // TODO: Skip just the cases that fail?
443 t.Skipf("some tests fail to build on %s", runtime.GOOS)
452 d, err := os.MkdirTemp("", filepath.Base(t.Name()))
460 exe := buildPtrTests(t, gopath, false)
461 exe2 := buildPtrTests(t, gopath, true)
463 // We (TestPointerChecks) return before the parallel subtest functions do,
464 // so we can't just defer os.RemoveAll(dir). Instead we have to wait for
465 // the parallel subtests to finish. This code looks racy but is not:
466 // the add +1 run in serial before testOne blocks. The -1 run in parallel
467 // after testOne finishes.
469 for _, pt := range ptrTests {
471 t.Run(pt.name, func(t *testing.T) {
472 atomic.AddInt32(&pending, +1)
474 if atomic.AddInt32(&pending, -1) == 0 {
478 testOne(t, pt, exe, exe2)
483 func buildPtrTests(t *testing.T, gopath string, cgocheck2 bool) (exe string) {
485 src := filepath.Join(gopath, "src", "ptrtest")
486 if err := os.MkdirAll(src, 0777); err != nil {
489 if err := os.WriteFile(filepath.Join(src, "go.mod"), []byte("module ptrtest"), 0666); err != nil {
493 // Prepare two cgo inputs: one for standard cgo and one for //export cgo.
494 // (The latter cannot have C definitions, only declarations.)
495 var cgo1, cgo2 bytes.Buffer
496 fmt.Fprintf(&cgo1, "package main\n\n/*\n")
497 fmt.Fprintf(&cgo2, "package main\n\n/*\n")
500 for _, pt := range ptrTests {
502 if strings.Contains(pt.support, "//export") {
505 fmt.Fprintf(cgo, "%s\n", pt.c)
506 fmt.Fprintf(&cgo1, "%s\n", pt.c1)
508 fmt.Fprintf(&cgo1, "*/\nimport \"C\"\n\n")
509 fmt.Fprintf(&cgo2, "*/\nimport \"C\"\n\n")
512 did1 := make(map[string]bool)
513 did2 := make(map[string]bool)
514 did1["os"] = true // for ptrTestMain
515 fmt.Fprintf(&cgo1, "import \"os\"\n")
517 for _, pt := range ptrTests {
520 if strings.Contains(pt.support, "//export") {
524 for _, imp := range pt.imports {
527 fmt.Fprintf(cgo, "import %q\n", imp)
532 // Func support and bodies.
533 for _, pt := range ptrTests {
535 if strings.Contains(pt.support, "//export") {
538 fmt.Fprintf(cgo, "%s\nfunc %s() {\n%s\n}\n", pt.support, pt.name, pt.body)
541 // Func list and main dispatch.
542 fmt.Fprintf(&cgo1, "var funcs = map[string]func() {\n")
543 for _, pt := range ptrTests {
544 fmt.Fprintf(&cgo1, "\t%q: %s,\n", pt.name, pt.name)
546 fmt.Fprintf(&cgo1, "}\n\n")
547 fmt.Fprintf(&cgo1, "%s\n", ptrTestMain)
549 if err := os.WriteFile(filepath.Join(src, "cgo1.go"), cgo1.Bytes(), 0666); err != nil {
552 if err := os.WriteFile(filepath.Join(src, "cgo2.go"), cgo2.Bytes(), 0666); err != nil {
556 exeName := "ptrtest.exe"
558 exeName = "ptrtest2.exe"
560 cmd := exec.Command("go", "build", "-o", exeName)
562 cmd.Env = append(os.Environ(), "GOPATH="+gopath)
565 for i, e := range cmd.Env {
566 if strings.HasPrefix(e, "GOEXPERIMENT=") {
567 cmd.Env[i] = e + ",cgocheck2"
572 cmd.Env = append(cmd.Env, "GOEXPERIMENT=cgocheck2")
575 out, err := cmd.CombinedOutput()
577 t.Fatalf("go build: %v\n%s", err, out)
580 return filepath.Join(src, exeName)
583 const ptrTestMain = `
585 for _, arg := range os.Args[1:] {
588 panic("missing func "+arg)
595 var csem = make(chan bool, 16)
597 func testOne(t *testing.T, pt ptrTest, exe, exe2 string) {
600 // Run the tests in parallel, but don't run too many
601 // executions in parallel, to avoid overloading the system.
602 runcmd := func(cgocheck string) ([]byte, error) {
604 defer func() { <-csem }()
610 cmd := exec.Command(x, pt.name)
611 cmd.Env = append(os.Environ(), "GODEBUG=cgocheck="+cgocheck)
612 return cmd.CombinedOutput()
616 buf, err := runcmd("1")
620 t.Fatalf("test marked expensive, but failed when not expensive: %v", err)
622 t.Errorf("failed unexpectedly with GODEBUG=cgocheck=1: %v", err)
633 buf, err := runcmd(cgocheck)
637 t.Fatalf("did not fail as expected")
638 } else if !bytes.Contains(buf, []byte("Go pointer")) {
640 t.Fatalf("did not print expected error (failed with %v)", err)
645 t.Fatalf("failed unexpectedly: %v", err)
649 // Make sure it passes with the expensive checks.
650 buf, err := runcmd("2")
653 t.Fatalf("failed unexpectedly with expensive checks: %v", err)
659 buf, err := runcmd("0")
662 t.Fatalf("failed unexpectedly with GODEBUG=cgocheck=0: %v", err)