mirror of
https://github.com/golang/go
synced 2024-10-02 04:18:33 -06:00
193088b246
Currently mmap returns an unsafe.Pointer that encodes OS errors as values less than 4096. In practice this is okay, but it borders on being really unsafe: for example, the value has to be checked immediately after return and if stack copying were ever to observe such a value, it would panic. It's also not remotely idiomatic. Fix this by making mmap return a separate pointer value and error, like a normal Go function. Updates #22218. Change-Id: Iefd965095ffc82cc91118872753a5d39d785c3a6 Reviewed-on: https://go-review.googlesource.com/71270 Run-TryBot: Austin Clements <austin@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
64 lines
1.6 KiB
Go
64 lines
1.6 KiB
Go
// Copyright 2010 The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package runtime
|
|
|
|
import "unsafe"
|
|
|
|
// Don't split the stack as this function may be invoked without a valid G,
|
|
// which prevents us from allocating more stack.
|
|
//go:nosplit
|
|
func sysAlloc(n uintptr, sysStat *uint64) unsafe.Pointer {
|
|
v, err := mmap(nil, n, _PROT_READ|_PROT_WRITE, _MAP_ANON|_MAP_PRIVATE, -1, 0)
|
|
if err != 0 {
|
|
return nil
|
|
}
|
|
mSysStatInc(sysStat, n)
|
|
return v
|
|
}
|
|
|
|
func sysUnused(v unsafe.Pointer, n uintptr) {
|
|
// Linux's MADV_DONTNEED is like BSD's MADV_FREE.
|
|
madvise(v, n, _MADV_FREE)
|
|
}
|
|
|
|
func sysUsed(v unsafe.Pointer, n uintptr) {
|
|
}
|
|
|
|
// Don't split the stack as this function may be invoked without a valid G,
|
|
// which prevents us from allocating more stack.
|
|
//go:nosplit
|
|
func sysFree(v unsafe.Pointer, n uintptr, sysStat *uint64) {
|
|
mSysStatDec(sysStat, n)
|
|
munmap(v, n)
|
|
}
|
|
|
|
func sysFault(v unsafe.Pointer, n uintptr) {
|
|
mmap(v, n, _PROT_NONE, _MAP_ANON|_MAP_PRIVATE|_MAP_FIXED, -1, 0)
|
|
}
|
|
|
|
func sysReserve(v unsafe.Pointer, n uintptr, reserved *bool) unsafe.Pointer {
|
|
*reserved = true
|
|
p, err := mmap(v, n, _PROT_NONE, _MAP_ANON|_MAP_PRIVATE, -1, 0)
|
|
if err != 0 {
|
|
return nil
|
|
}
|
|
return p
|
|
}
|
|
|
|
const (
|
|
_ENOMEM = 12
|
|
)
|
|
|
|
func sysMap(v unsafe.Pointer, n uintptr, reserved bool, sysStat *uint64) {
|
|
mSysStatInc(sysStat, n)
|
|
p, err := mmap(v, n, _PROT_READ|_PROT_WRITE, _MAP_ANON|_MAP_FIXED|_MAP_PRIVATE, -1, 0)
|
|
if err == _ENOMEM {
|
|
throw("runtime: out of memory")
|
|
}
|
|
if p != v || err != 0 {
|
|
throw("runtime: cannot map pages in arena address space")
|
|
}
|
|
}
|