add demo for get all goroutine data

go/linkname/private_fields.go

@@ -0,0 +1,55 @@
+package main
+
+import (
+	"fmt"
+	"unsafe"
+	_ "unsafe"
+)
+
+//go:linkname allgs runtime.allgs
+var allgs []*g
+
+//go:linkname gentraceback runtime.gentraceback
+func gentraceback(pc0, sp0, lr0 uintptr, gp *g, skip int, pcbuf *uintptr, max int, callback func(uintptr, unsafe.Pointer) bool, v unsafe.Pointer, flags uint) int
+
+type StackRecord struct {
+	Stack0 [32]uintptr // stack trace for this record; ends at first 0 entry
+}
+
+type g struct {
+	// Stack parameters.
+	// stack describes the actual stack memory: [stack.lo, stack.hi).
+	// stackguard0 is the stack pointer compared in the Go stack growth prologue.
+	// It is stack.lo+StackGuard normally, but can be StackPreempt to trigger a preemption.
+	// stackguard1 is the stack pointer compared in the C stack growth prologue.
+	// It is stack.lo+StackGuard on g0 and gsignal stacks.
+	// It is ~0 on other goroutine stacks, to trigger a call to morestackc (and crash).
+	stack       [2]uintptr // offset known to runtime/cgo
+	stackguard0 uintptr    // offset known to liblink
+	stackguard1 uintptr    // offset known to liblink
+
+	_panic       uintptr // innermost panic - offset known to liblink
+	_defer       uintptr // innermost defer
+	m            uintptr // current m; offset known to arm liblink
+	sched        [7]uintptr
+	syscallsp    uintptr        // if status==Gsyscall, syscallsp = sched.sp to use during gc
+	syscallpc    uintptr        // if status==Gsyscall, syscallpc = sched.pc to use during gc
+	stktopsp     uintptr        // expected sp at top of stack, to check in traceback
+	param        unsafe.Pointer // passed parameter on wakeup
+	atomicstatus uint32
+	stackLock    uint32 // sigprof/scang lock; TODO: fold in to atomicstatus
+	goid         int64
+}
+
+func main() {
+	fmt.Println(allgs)
+	fmt.Println(allgs[0].stack[0], allgs[0].stack[1])
+
+	for _, gp := range allgs {
+		var x StackRecord
+		if gp.goid != 1 {
+			gentraceback(gp.sched[1], gp.sched[0], 0, gp, 0, &x.Stack0[0], len(x.Stack0), nil, nil, 0)
+			fmt.Println(x)
+		}
+	}
+}