Initial commit: Go 1.23 release state
This commit is contained in:
Vorapol Rinsatitnon
776
src/runtime/cgocall.go
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776
src/runtime/cgocall.go
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@@ -0,0 +1,776 @@
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// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Cgo call and callback support.
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//
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// To call into the C function f from Go, the cgo-generated code calls
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// runtime.cgocall(_cgo_Cfunc_f, frame), where _cgo_Cfunc_f is a
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// gcc-compiled function written by cgo.
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//
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// runtime.cgocall (below) calls entersyscall so as not to block
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// other goroutines or the garbage collector, and then calls
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// runtime.asmcgocall(_cgo_Cfunc_f, frame).
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//
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// runtime.asmcgocall (in asm_$GOARCH.s) switches to the m->g0 stack
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// (assumed to be an operating system-allocated stack, so safe to run
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// gcc-compiled code on) and calls _cgo_Cfunc_f(frame).
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//
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// _cgo_Cfunc_f invokes the actual C function f with arguments
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// taken from the frame structure, records the results in the frame,
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// and returns to runtime.asmcgocall.
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//
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// After it regains control, runtime.asmcgocall switches back to the
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// original g (m->curg)'s stack and returns to runtime.cgocall.
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//
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// After it regains control, runtime.cgocall calls exitsyscall, which blocks
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// until this m can run Go code without violating the $GOMAXPROCS limit,
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// and then unlocks g from m.
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//
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// The above description skipped over the possibility of the gcc-compiled
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// function f calling back into Go. If that happens, we continue down
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// the rabbit hole during the execution of f.
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//
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// To make it possible for gcc-compiled C code to call a Go function p.GoF,
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// cgo writes a gcc-compiled function named GoF (not p.GoF, since gcc doesn't
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// know about packages). The gcc-compiled C function f calls GoF.
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//
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// GoF initializes "frame", a structure containing all of its
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// arguments and slots for p.GoF's results. It calls
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// crosscall2(_cgoexp_GoF, frame, framesize, ctxt) using the gcc ABI.
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//
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// crosscall2 (in cgo/asm_$GOARCH.s) is a four-argument adapter from
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// the gcc function call ABI to the gc function call ABI. At this
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// point we're in the Go runtime, but we're still running on m.g0's
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// stack and outside the $GOMAXPROCS limit. crosscall2 calls
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// runtime.cgocallback(_cgoexp_GoF, frame, ctxt) using the gc ABI.
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// (crosscall2's framesize argument is no longer used, but there's one
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// case where SWIG calls crosscall2 directly and expects to pass this
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// argument. See _cgo_panic.)
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//
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// runtime.cgocallback (in asm_$GOARCH.s) switches from m.g0's stack
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// to the original g (m.curg)'s stack, on which it calls
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// runtime.cgocallbackg(_cgoexp_GoF, frame, ctxt). As part of the
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// stack switch, runtime.cgocallback saves the current SP as
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// m.g0.sched.sp, so that any use of m.g0's stack during the execution
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// of the callback will be done below the existing stack frames.
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// Before overwriting m.g0.sched.sp, it pushes the old value on the
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// m.g0 stack, so that it can be restored later.
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//
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// runtime.cgocallbackg (below) is now running on a real goroutine
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// stack (not an m.g0 stack). First it calls runtime.exitsyscall, which will
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// block until the $GOMAXPROCS limit allows running this goroutine.
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// Once exitsyscall has returned, it is safe to do things like call the memory
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// allocator or invoke the Go callback function. runtime.cgocallbackg
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// first defers a function to unwind m.g0.sched.sp, so that if p.GoF
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// panics, m.g0.sched.sp will be restored to its old value: the m.g0 stack
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// and the m.curg stack will be unwound in lock step.
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// Then it calls _cgoexp_GoF(frame).
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//
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// _cgoexp_GoF, which was generated by cmd/cgo, unpacks the arguments
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// from frame, calls p.GoF, writes the results back to frame, and
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// returns. Now we start unwinding this whole process.
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//
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// runtime.cgocallbackg pops but does not execute the deferred
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// function to unwind m.g0.sched.sp, calls runtime.entersyscall, and
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// returns to runtime.cgocallback.
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//
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// After it regains control, runtime.cgocallback switches back to
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// m.g0's stack (the pointer is still in m.g0.sched.sp), restores the old
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// m.g0.sched.sp value from the stack, and returns to crosscall2.
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//
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// crosscall2 restores the callee-save registers for gcc and returns
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// to GoF, which unpacks any result values and returns to f.
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package runtime
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import (
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"internal/abi"
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"internal/goarch"
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"internal/goexperiment"
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"runtime/internal/sys"
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"unsafe"
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)
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// Addresses collected in a cgo backtrace when crashing.
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// Length must match arg.Max in x_cgo_callers in runtime/cgo/gcc_traceback.c.
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type cgoCallers [32]uintptr
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// argset matches runtime/cgo/linux_syscall.c:argset_t
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type argset struct {
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args unsafe.Pointer
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retval uintptr
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}
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// wrapper for syscall package to call cgocall for libc (cgo) calls.
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//
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//go:linkname syscall_cgocaller syscall.cgocaller
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//go:nosplit
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//go:uintptrescapes
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func syscall_cgocaller(fn unsafe.Pointer, args ...uintptr) uintptr {
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as := argset{args: unsafe.Pointer(&args[0])}
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cgocall(fn, unsafe.Pointer(&as))
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return as.retval
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}
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var ncgocall uint64 // number of cgo calls in total for dead m
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// Call from Go to C.
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//
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// This must be nosplit because it's used for syscalls on some
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// platforms. Syscalls may have untyped arguments on the stack, so
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// it's not safe to grow or scan the stack.
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//
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// cgocall should be an internal detail,
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// but widely used packages access it using linkname.
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// Notable members of the hall of shame include:
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// - github.com/ebitengine/purego
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//
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// Do not remove or change the type signature.
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// See go.dev/issue/67401.
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//
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//go:linkname cgocall
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//go:nosplit
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func cgocall(fn, arg unsafe.Pointer) int32 {
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if !iscgo && GOOS != "solaris" && GOOS != "illumos" && GOOS != "windows" {
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throw("cgocall unavailable")
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}
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if fn == nil {
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throw("cgocall nil")
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}
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if raceenabled {
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racereleasemerge(unsafe.Pointer(&racecgosync))
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}
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mp := getg().m
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mp.ncgocall++
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// Reset traceback.
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mp.cgoCallers[0] = 0
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// Announce we are entering a system call
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// so that the scheduler knows to create another
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// M to run goroutines while we are in the
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// foreign code.
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//
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// The call to asmcgocall is guaranteed not to
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// grow the stack and does not allocate memory,
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// so it is safe to call while "in a system call", outside
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// the $GOMAXPROCS accounting.
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//
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// fn may call back into Go code, in which case we'll exit the
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// "system call", run the Go code (which may grow the stack),
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// and then re-enter the "system call" reusing the PC and SP
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// saved by entersyscall here.
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entersyscall()
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// Tell asynchronous preemption that we're entering external
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// code. We do this after entersyscall because this may block
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// and cause an async preemption to fail, but at this point a
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// sync preemption will succeed (though this is not a matter
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// of correctness).
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osPreemptExtEnter(mp)
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mp.incgo = true
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// We use ncgo as a check during execution tracing for whether there is
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// any C on the call stack, which there will be after this point. If
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// there isn't, we can use frame pointer unwinding to collect call
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// stacks efficiently. This will be the case for the first Go-to-C call
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// on a stack, so it's preferable to update it here, after we emit a
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// trace event in entersyscall above.
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mp.ncgo++
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errno := asmcgocall(fn, arg)
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// Update accounting before exitsyscall because exitsyscall may
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// reschedule us on to a different M.
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mp.incgo = false
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mp.ncgo--
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osPreemptExtExit(mp)
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// Save current syscall parameters, so m.winsyscall can be
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// used again if callback decide to make syscall.
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winsyscall := mp.winsyscall
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exitsyscall()
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getg().m.winsyscall = winsyscall
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// Note that raceacquire must be called only after exitsyscall has
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// wired this M to a P.
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if raceenabled {
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raceacquire(unsafe.Pointer(&racecgosync))
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}
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// From the garbage collector's perspective, time can move
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// backwards in the sequence above. If there's a callback into
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// Go code, GC will see this function at the call to
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// asmcgocall. When the Go call later returns to C, the
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// syscall PC/SP is rolled back and the GC sees this function
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// back at the call to entersyscall. Normally, fn and arg
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// would be live at entersyscall and dead at asmcgocall, so if
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// time moved backwards, GC would see these arguments as dead
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// and then live. Prevent these undead arguments from crashing
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// GC by forcing them to stay live across this time warp.
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KeepAlive(fn)
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KeepAlive(arg)
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KeepAlive(mp)
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return errno
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}
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// Set or reset the system stack bounds for a callback on sp.
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//
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// Must be nosplit because it is called by needm prior to fully initializing
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// the M.
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//
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//go:nosplit
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func callbackUpdateSystemStack(mp *m, sp uintptr, signal bool) {
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g0 := mp.g0
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inBound := sp > g0.stack.lo && sp <= g0.stack.hi
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if mp.ncgo > 0 && !inBound {
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// ncgo > 0 indicates that this M was in Go further up the stack
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// (it called C and is now receiving a callback).
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//
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// !inBound indicates that we were called with SP outside the
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// expected system stack bounds (C changed the stack out from
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// under us between the cgocall and cgocallback?).
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//
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// It is not safe for the C call to change the stack out from
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// under us, so throw.
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// Note that this case isn't possible for signal == true, as
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// that is always passing a new M from needm.
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// Stack is bogus, but reset the bounds anyway so we can print.
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hi := g0.stack.hi
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lo := g0.stack.lo
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g0.stack.hi = sp + 1024
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g0.stack.lo = sp - 32*1024
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g0.stackguard0 = g0.stack.lo + stackGuard
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g0.stackguard1 = g0.stackguard0
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print("M ", mp.id, " procid ", mp.procid, " runtime: cgocallback with sp=", hex(sp), " out of bounds [", hex(lo), ", ", hex(hi), "]")
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print("\n")
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exit(2)
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}
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if !mp.isextra {
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// We allocated the stack for standard Ms. Don't replace the
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// stack bounds with estimated ones when we already initialized
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// with the exact ones.
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return
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}
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// This M does not have Go further up the stack. However, it may have
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// previously called into Go, initializing the stack bounds. Between
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// that call returning and now the stack may have changed (perhaps the
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// C thread is running a coroutine library). We need to update the
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// stack bounds for this case.
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//
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// N.B. we need to update the stack bounds even if SP appears to
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// already be in bounds. Our "bounds" may actually be estimated dummy
|
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// bounds (below). The actual stack bounds could have shifted but still
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// have partial overlap with our dummy bounds. If we failed to update
|
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// in that case, we could find ourselves seemingly called near the
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// bottom of the stack bounds, where we quickly run out of space.
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// Set the stack bounds to match the current stack. If we don't
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// actually know how big the stack is, like we don't know how big any
|
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// scheduling stack is, but we assume there's at least 32 kB. If we
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// can get a more accurate stack bound from pthread, use that, provided
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// it actually contains SP..
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g0.stack.hi = sp + 1024
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g0.stack.lo = sp - 32*1024
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if !signal && _cgo_getstackbound != nil {
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// Don't adjust if called from the signal handler.
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// We are on the signal stack, not the pthread stack.
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// (We could get the stack bounds from sigaltstack, but
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// we're getting out of the signal handler very soon
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// anyway. Not worth it.)
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var bounds [2]uintptr
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asmcgocall(_cgo_getstackbound, unsafe.Pointer(&bounds))
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// getstackbound is an unsupported no-op on Windows.
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//
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// Don't use these bounds if they don't contain SP. Perhaps we
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// were called by something not using the standard thread
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// stack.
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if bounds[0] != 0 && sp > bounds[0] && sp <= bounds[1] {
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g0.stack.lo = bounds[0]
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g0.stack.hi = bounds[1]
|
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}
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}
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g0.stackguard0 = g0.stack.lo + stackGuard
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g0.stackguard1 = g0.stackguard0
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}
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// Call from C back to Go. fn must point to an ABIInternal Go entry-point.
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//
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//go:nosplit
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func cgocallbackg(fn, frame unsafe.Pointer, ctxt uintptr) {
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gp := getg()
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if gp != gp.m.curg {
|
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println("runtime: bad g in cgocallback")
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exit(2)
|
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}
|
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|
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sp := gp.m.g0.sched.sp // system sp saved by cgocallback.
|
||||
callbackUpdateSystemStack(gp.m, sp, false)
|
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|
||||
// The call from C is on gp.m's g0 stack, so we must ensure
|
||||
// that we stay on that M. We have to do this before calling
|
||||
// exitsyscall, since it would otherwise be free to move us to
|
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// a different M. The call to unlockOSThread is in this function
|
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// after cgocallbackg1, or in the case of panicking, in unwindm.
|
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lockOSThread()
|
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|
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checkm := gp.m
|
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|
||||
// Save current syscall parameters, so m.winsyscall can be
|
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// used again if callback decide to make syscall.
|
||||
winsyscall := gp.m.winsyscall
|
||||
|
||||
// entersyscall saves the caller's SP to allow the GC to trace the Go
|
||||
// stack. However, since we're returning to an earlier stack frame and
|
||||
// need to pair with the entersyscall() call made by cgocall, we must
|
||||
// save syscall* and let reentersyscall restore them.
|
||||
//
|
||||
// Note: savedsp and savedbp MUST be held in locals as an unsafe.Pointer.
|
||||
// When we call into Go, the stack is free to be moved. If these locals
|
||||
// aren't visible in the stack maps, they won't get updated properly,
|
||||
// and will end up being stale when restored by reentersyscall.
|
||||
savedsp := unsafe.Pointer(gp.syscallsp)
|
||||
savedpc := gp.syscallpc
|
||||
savedbp := unsafe.Pointer(gp.syscallbp)
|
||||
exitsyscall() // coming out of cgo call
|
||||
gp.m.incgo = false
|
||||
if gp.m.isextra {
|
||||
gp.m.isExtraInC = false
|
||||
}
|
||||
|
||||
osPreemptExtExit(gp.m)
|
||||
|
||||
if gp.nocgocallback {
|
||||
panic("runtime: function marked with #cgo nocallback called back into Go")
|
||||
}
|
||||
|
||||
cgocallbackg1(fn, frame, ctxt)
|
||||
|
||||
// At this point we're about to call unlockOSThread.
|
||||
// The following code must not change to a different m.
|
||||
// This is enforced by checking incgo in the schedule function.
|
||||
gp.m.incgo = true
|
||||
unlockOSThread()
|
||||
|
||||
if gp.m.isextra {
|
||||
gp.m.isExtraInC = true
|
||||
}
|
||||
|
||||
if gp.m != checkm {
|
||||
throw("m changed unexpectedly in cgocallbackg")
|
||||
}
|
||||
|
||||
osPreemptExtEnter(gp.m)
|
||||
|
||||
// going back to cgo call
|
||||
reentersyscall(savedpc, uintptr(savedsp), uintptr(savedbp))
|
||||
|
||||
gp.m.winsyscall = winsyscall
|
||||
}
|
||||
|
||||
func cgocallbackg1(fn, frame unsafe.Pointer, ctxt uintptr) {
|
||||
gp := getg()
|
||||
|
||||
if gp.m.needextram || extraMWaiters.Load() > 0 {
|
||||
gp.m.needextram = false
|
||||
systemstack(newextram)
|
||||
}
|
||||
|
||||
if ctxt != 0 {
|
||||
s := append(gp.cgoCtxt, ctxt)
|
||||
|
||||
// Now we need to set gp.cgoCtxt = s, but we could get
|
||||
// a SIGPROF signal while manipulating the slice, and
|
||||
// the SIGPROF handler could pick up gp.cgoCtxt while
|
||||
// tracing up the stack. We need to ensure that the
|
||||
// handler always sees a valid slice, so set the
|
||||
// values in an order such that it always does.
|
||||
p := (*slice)(unsafe.Pointer(&gp.cgoCtxt))
|
||||
atomicstorep(unsafe.Pointer(&p.array), unsafe.Pointer(&s[0]))
|
||||
p.cap = cap(s)
|
||||
p.len = len(s)
|
||||
|
||||
defer func(gp *g) {
|
||||
// Decrease the length of the slice by one, safely.
|
||||
p := (*slice)(unsafe.Pointer(&gp.cgoCtxt))
|
||||
p.len--
|
||||
}(gp)
|
||||
}
|
||||
|
||||
if gp.m.ncgo == 0 {
|
||||
// The C call to Go came from a thread not currently running
|
||||
// any Go. In the case of -buildmode=c-archive or c-shared,
|
||||
// this call may be coming in before package initialization
|
||||
// is complete. Wait until it is.
|
||||
<-main_init_done
|
||||
}
|
||||
|
||||
// Check whether the profiler needs to be turned on or off; this route to
|
||||
// run Go code does not use runtime.execute, so bypasses the check there.
|
||||
hz := sched.profilehz
|
||||
if gp.m.profilehz != hz {
|
||||
setThreadCPUProfiler(hz)
|
||||
}
|
||||
|
||||
// Add entry to defer stack in case of panic.
|
||||
restore := true
|
||||
defer unwindm(&restore)
|
||||
|
||||
if raceenabled {
|
||||
raceacquire(unsafe.Pointer(&racecgosync))
|
||||
}
|
||||
|
||||
// Invoke callback. This function is generated by cmd/cgo and
|
||||
// will unpack the argument frame and call the Go function.
|
||||
var cb func(frame unsafe.Pointer)
|
||||
cbFV := funcval{uintptr(fn)}
|
||||
*(*unsafe.Pointer)(unsafe.Pointer(&cb)) = noescape(unsafe.Pointer(&cbFV))
|
||||
cb(frame)
|
||||
|
||||
if raceenabled {
|
||||
racereleasemerge(unsafe.Pointer(&racecgosync))
|
||||
}
|
||||
|
||||
// Do not unwind m->g0->sched.sp.
|
||||
// Our caller, cgocallback, will do that.
|
||||
restore = false
|
||||
}
|
||||
|
||||
func unwindm(restore *bool) {
|
||||
if *restore {
|
||||
// Restore sp saved by cgocallback during
|
||||
// unwind of g's stack (see comment at top of file).
|
||||
mp := acquirem()
|
||||
sched := &mp.g0.sched
|
||||
sched.sp = *(*uintptr)(unsafe.Pointer(sched.sp + alignUp(sys.MinFrameSize, sys.StackAlign)))
|
||||
|
||||
// Do the accounting that cgocall will not have a chance to do
|
||||
// during an unwind.
|
||||
//
|
||||
// In the case where a Go call originates from C, ncgo is 0
|
||||
// and there is no matching cgocall to end.
|
||||
if mp.ncgo > 0 {
|
||||
mp.incgo = false
|
||||
mp.ncgo--
|
||||
osPreemptExtExit(mp)
|
||||
}
|
||||
|
||||
// Undo the call to lockOSThread in cgocallbackg, only on the
|
||||
// panicking path. In normal return case cgocallbackg will call
|
||||
// unlockOSThread, ensuring no preemption point after the unlock.
|
||||
// Here we don't need to worry about preemption, because we're
|
||||
// panicking out of the callback and unwinding the g0 stack,
|
||||
// instead of reentering cgo (which requires the same thread).
|
||||
unlockOSThread()
|
||||
|
||||
releasem(mp)
|
||||
}
|
||||
}
|
||||
|
||||
// called from assembly.
|
||||
func badcgocallback() {
|
||||
throw("misaligned stack in cgocallback")
|
||||
}
|
||||
|
||||
// called from (incomplete) assembly.
|
||||
func cgounimpl() {
|
||||
throw("cgo not implemented")
|
||||
}
|
||||
|
||||
var racecgosync uint64 // represents possible synchronization in C code
|
||||
|
||||
// Pointer checking for cgo code.
|
||||
|
||||
// We want to detect all cases where a program that does not use
|
||||
// unsafe makes a cgo call passing a Go pointer to memory that
|
||||
// contains an unpinned Go pointer. Here a Go pointer is defined as a
|
||||
// pointer to memory allocated by the Go runtime. Programs that use
|
||||
// unsafe can evade this restriction easily, so we don't try to catch
|
||||
// them. The cgo program will rewrite all possibly bad pointer
|
||||
// arguments to call cgoCheckPointer, where we can catch cases of a Go
|
||||
// pointer pointing to an unpinned Go pointer.
|
||||
|
||||
// Complicating matters, taking the address of a slice or array
|
||||
// element permits the C program to access all elements of the slice
|
||||
// or array. In that case we will see a pointer to a single element,
|
||||
// but we need to check the entire data structure.
|
||||
|
||||
// The cgoCheckPointer call takes additional arguments indicating that
|
||||
// it was called on an address expression. An additional argument of
|
||||
// true means that it only needs to check a single element. An
|
||||
// additional argument of a slice or array means that it needs to
|
||||
// check the entire slice/array, but nothing else. Otherwise, the
|
||||
// pointer could be anything, and we check the entire heap object,
|
||||
// which is conservative but safe.
|
||||
|
||||
// When and if we implement a moving garbage collector,
|
||||
// cgoCheckPointer will pin the pointer for the duration of the cgo
|
||||
// call. (This is necessary but not sufficient; the cgo program will
|
||||
// also have to change to pin Go pointers that cannot point to Go
|
||||
// pointers.)
|
||||
|
||||
// cgoCheckPointer checks if the argument contains a Go pointer that
|
||||
// points to an unpinned Go pointer, and panics if it does.
|
||||
func cgoCheckPointer(ptr any, arg any) {
|
||||
if !goexperiment.CgoCheck2 && debug.cgocheck == 0 {
|
||||
return
|
||||
}
|
||||
|
||||
ep := efaceOf(&ptr)
|
||||
t := ep._type
|
||||
|
||||
top := true
|
||||
if arg != nil && (t.Kind_&abi.KindMask == abi.Pointer || t.Kind_&abi.KindMask == abi.UnsafePointer) {
|
||||
p := ep.data
|
||||
if t.Kind_&abi.KindDirectIface == 0 {
|
||||
p = *(*unsafe.Pointer)(p)
|
||||
}
|
||||
if p == nil || !cgoIsGoPointer(p) {
|
||||
return
|
||||
}
|
||||
aep := efaceOf(&arg)
|
||||
switch aep._type.Kind_ & abi.KindMask {
|
||||
case abi.Bool:
|
||||
if t.Kind_&abi.KindMask == abi.UnsafePointer {
|
||||
// We don't know the type of the element.
|
||||
break
|
||||
}
|
||||
pt := (*ptrtype)(unsafe.Pointer(t))
|
||||
cgoCheckArg(pt.Elem, p, true, false, cgoCheckPointerFail)
|
||||
return
|
||||
case abi.Slice:
|
||||
// Check the slice rather than the pointer.
|
||||
ep = aep
|
||||
t = ep._type
|
||||
case abi.Array:
|
||||
// Check the array rather than the pointer.
|
||||
// Pass top as false since we have a pointer
|
||||
// to the array.
|
||||
ep = aep
|
||||
t = ep._type
|
||||
top = false
|
||||
default:
|
||||
throw("can't happen")
|
||||
}
|
||||
}
|
||||
|
||||
cgoCheckArg(t, ep.data, t.Kind_&abi.KindDirectIface == 0, top, cgoCheckPointerFail)
|
||||
}
|
||||
|
||||
const cgoCheckPointerFail = "cgo argument has Go pointer to unpinned Go pointer"
|
||||
const cgoResultFail = "cgo result is unpinned Go pointer or points to unpinned Go pointer"
|
||||
|
||||
// cgoCheckArg is the real work of cgoCheckPointer. The argument p
|
||||
// is either a pointer to the value (of type t), or the value itself,
|
||||
// depending on indir. The top parameter is whether we are at the top
|
||||
// level, where Go pointers are allowed. Go pointers to pinned objects are
|
||||
// allowed as long as they don't reference other unpinned pointers.
|
||||
func cgoCheckArg(t *_type, p unsafe.Pointer, indir, top bool, msg string) {
|
||||
if !t.Pointers() || p == nil {
|
||||
// If the type has no pointers there is nothing to do.
|
||||
return
|
||||
}
|
||||
|
||||
switch t.Kind_ & abi.KindMask {
|
||||
default:
|
||||
throw("can't happen")
|
||||
case abi.Array:
|
||||
at := (*arraytype)(unsafe.Pointer(t))
|
||||
if !indir {
|
||||
if at.Len != 1 {
|
||||
throw("can't happen")
|
||||
}
|
||||
cgoCheckArg(at.Elem, p, at.Elem.Kind_&abi.KindDirectIface == 0, top, msg)
|
||||
return
|
||||
}
|
||||
for i := uintptr(0); i < at.Len; i++ {
|
||||
cgoCheckArg(at.Elem, p, true, top, msg)
|
||||
p = add(p, at.Elem.Size_)
|
||||
}
|
||||
case abi.Chan, abi.Map:
|
||||
// These types contain internal pointers that will
|
||||
// always be allocated in the Go heap. It's never OK
|
||||
// to pass them to C.
|
||||
panic(errorString(msg))
|
||||
case abi.Func:
|
||||
if indir {
|
||||
p = *(*unsafe.Pointer)(p)
|
||||
}
|
||||
if !cgoIsGoPointer(p) {
|
||||
return
|
||||
}
|
||||
panic(errorString(msg))
|
||||
case abi.Interface:
|
||||
it := *(**_type)(p)
|
||||
if it == nil {
|
||||
return
|
||||
}
|
||||
// A type known at compile time is OK since it's
|
||||
// constant. A type not known at compile time will be
|
||||
// in the heap and will not be OK.
|
||||
if inheap(uintptr(unsafe.Pointer(it))) {
|
||||
panic(errorString(msg))
|
||||
}
|
||||
p = *(*unsafe.Pointer)(add(p, goarch.PtrSize))
|
||||
if !cgoIsGoPointer(p) {
|
||||
return
|
||||
}
|
||||
if !top && !isPinned(p) {
|
||||
panic(errorString(msg))
|
||||
}
|
||||
cgoCheckArg(it, p, it.Kind_&abi.KindDirectIface == 0, false, msg)
|
||||
case abi.Slice:
|
||||
st := (*slicetype)(unsafe.Pointer(t))
|
||||
s := (*slice)(p)
|
||||
p = s.array
|
||||
if p == nil || !cgoIsGoPointer(p) {
|
||||
return
|
||||
}
|
||||
if !top && !isPinned(p) {
|
||||
panic(errorString(msg))
|
||||
}
|
||||
if !st.Elem.Pointers() {
|
||||
return
|
||||
}
|
||||
for i := 0; i < s.cap; i++ {
|
||||
cgoCheckArg(st.Elem, p, true, false, msg)
|
||||
p = add(p, st.Elem.Size_)
|
||||
}
|
||||
case abi.String:
|
||||
ss := (*stringStruct)(p)
|
||||
if !cgoIsGoPointer(ss.str) {
|
||||
return
|
||||
}
|
||||
if !top && !isPinned(ss.str) {
|
||||
panic(errorString(msg))
|
||||
}
|
||||
case abi.Struct:
|
||||
st := (*structtype)(unsafe.Pointer(t))
|
||||
if !indir {
|
||||
if len(st.Fields) != 1 {
|
||||
throw("can't happen")
|
||||
}
|
||||
cgoCheckArg(st.Fields[0].Typ, p, st.Fields[0].Typ.Kind_&abi.KindDirectIface == 0, top, msg)
|
||||
return
|
||||
}
|
||||
for _, f := range st.Fields {
|
||||
if !f.Typ.Pointers() {
|
||||
continue
|
||||
}
|
||||
cgoCheckArg(f.Typ, add(p, f.Offset), true, top, msg)
|
||||
}
|
||||
case abi.Pointer, abi.UnsafePointer:
|
||||
if indir {
|
||||
p = *(*unsafe.Pointer)(p)
|
||||
if p == nil {
|
||||
return
|
||||
}
|
||||
}
|
||||
|
||||
if !cgoIsGoPointer(p) {
|
||||
return
|
||||
}
|
||||
if !top && !isPinned(p) {
|
||||
panic(errorString(msg))
|
||||
}
|
||||
|
||||
cgoCheckUnknownPointer(p, msg)
|
||||
}
|
||||
}
|
||||
|
||||
// cgoCheckUnknownPointer is called for an arbitrary pointer into Go
|
||||
// memory. It checks whether that Go memory contains any other
|
||||
// pointer into unpinned Go memory. If it does, we panic.
|
||||
// The return values are unused but useful to see in panic tracebacks.
|
||||
func cgoCheckUnknownPointer(p unsafe.Pointer, msg string) (base, i uintptr) {
|
||||
if inheap(uintptr(p)) {
|
||||
b, span, _ := findObject(uintptr(p), 0, 0)
|
||||
base = b
|
||||
if base == 0 {
|
||||
return
|
||||
}
|
||||
tp := span.typePointersOfUnchecked(base)
|
||||
for {
|
||||
var addr uintptr
|
||||
if tp, addr = tp.next(base + span.elemsize); addr == 0 {
|
||||
break
|
||||
}
|
||||
pp := *(*unsafe.Pointer)(unsafe.Pointer(addr))
|
||||
if cgoIsGoPointer(pp) && !isPinned(pp) {
|
||||
panic(errorString(msg))
|
||||
}
|
||||
}
|
||||
return
|
||||
}
|
||||
|
||||
for _, datap := range activeModules() {
|
||||
if cgoInRange(p, datap.data, datap.edata) || cgoInRange(p, datap.bss, datap.ebss) {
|
||||
// We have no way to know the size of the object.
|
||||
// We have to assume that it might contain a pointer.
|
||||
panic(errorString(msg))
|
||||
}
|
||||
// In the text or noptr sections, we know that the
|
||||
// pointer does not point to a Go pointer.
|
||||
}
|
||||
|
||||
return
|
||||
}
|
||||
|
||||
// cgoIsGoPointer reports whether the pointer is a Go pointer--a
|
||||
// pointer to Go memory. We only care about Go memory that might
|
||||
// contain pointers.
|
||||
//
|
||||
//go:nosplit
|
||||
//go:nowritebarrierrec
|
||||
func cgoIsGoPointer(p unsafe.Pointer) bool {
|
||||
if p == nil {
|
||||
return false
|
||||
}
|
||||
|
||||
if inHeapOrStack(uintptr(p)) {
|
||||
return true
|
||||
}
|
||||
|
||||
for _, datap := range activeModules() {
|
||||
if cgoInRange(p, datap.data, datap.edata) || cgoInRange(p, datap.bss, datap.ebss) {
|
||||
return true
|
||||
}
|
||||
}
|
||||
|
||||
return false
|
||||
}
|
||||
|
||||
// cgoInRange reports whether p is between start and end.
|
||||
//
|
||||
//go:nosplit
|
||||
//go:nowritebarrierrec
|
||||
func cgoInRange(p unsafe.Pointer, start, end uintptr) bool {
|
||||
return start <= uintptr(p) && uintptr(p) < end
|
||||
}
|
||||
|
||||
// cgoCheckResult is called to check the result parameter of an
|
||||
// exported Go function. It panics if the result is or contains any
|
||||
// other pointer into unpinned Go memory.
|
||||
func cgoCheckResult(val any) {
|
||||
if !goexperiment.CgoCheck2 && debug.cgocheck == 0 {
|
||||
return
|
||||
}
|
||||
|
||||
ep := efaceOf(&val)
|
||||
t := ep._type
|
||||
cgoCheckArg(t, ep.data, t.Kind_&abi.KindDirectIface == 0, false, cgoResultFail)
|
||||
}
|
||||
Reference in New Issue
Block a user