internal/syscall/unix: use runtime.gostring for Gostring

Under the race detector, checkptr flags uses of unsafe.Slice that
result in slices that straddle multiple Go allocations.
Avoid that scenario by calling existing runtime code.

This fixes a failure on the darwin-.*-race builders introduced in
CL 446178.

Change-Id: I6e0fdb37e3c3f38d97939a8799bb4d10f519c5b9
Reviewed-on: https://go-review.googlesource.com/c/go/+/449936
Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Bryan Mills <bcmills@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Auto-Submit: Ian Lance Taylor <iant@golang.org>

diff --git a/src/internal/syscall/unix/net_darwin.go b/src/internal/syscall/unix/net_darwin.go
index 98403596938641ec65794d547dd8f24d916d58dc..b9da4f1dc75bfdf3de93c4d57be68b26c33e8cd3 100644 (file)
--- a/src/internal/syscall/unix/net_darwin.go
+++ b/src/internal/syscall/unix/net_darwin.go
@@ -95,17 +95,11 @@ func GaiStrerror(ecode int) string {
        return GoString((*byte)(unsafe.Pointer(r1)))
 }
 
+// Implemented in the runtime package.
+func gostring(*byte) string
+
 func GoString(p *byte) string {
-       if p == nil {
-               return ""
-       }
-       x := unsafe.Slice(p, 1e9)
-       for i, c := range x {
-               if c == 0 {
-                       return string(x[:i])
-               }
-       }
-       return ""
+       return gostring(p)
 }
 
 //go:linkname syscall_syscall syscall.syscall

diff --git a/src/runtime/string.go b/src/runtime/string.go
index eaade640c411dd42a94a5becc027a394fc05173f..a00976be59b974d42845a3b06596ea05435f765f 100644 (file)
--- a/src/runtime/string.go
+++ b/src/runtime/string.go
@@ -325,6 +325,13 @@ func gostring(p *byte) string {
        return s
 }
 
+// internal_syscall_gostring is a version of gostring for internal/syscall/unix.
+//
+//go:linkname internal_syscall_gostring internal/syscall/unix.gostring
+func internal_syscall_gostring(p *byte) string {
+       return gostring(p)
+}
+
 func gostringn(p *byte, l int) string {
        if l == 0 {
                return ""