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//go:build darwin || linux
// +build darwin linux
/*
* Copyright 2021 ByteDance Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package loader
import (
`fmt`
`os`
`reflect`
`syscall`
`unsafe`
)
const (
_AP = syscall.MAP_ANON | syscall.MAP_PRIVATE
_RX = syscall.PROT_READ | syscall.PROT_EXEC
_RW = syscall.PROT_READ | syscall.PROT_WRITE
)
type Loader []byte
type Function unsafe.Pointer
func (self Loader) Load(fn string, fp int, args int, argPtrs []bool, localPtrs []bool) (f Function) {
p := os.Getpagesize()
n := (((len(self) - 1) / p) + 1) * p
/* register the function */
m := mmap(n)
v := fmt.Sprintf("runtime.__%s_%x", fn, m)
registerFunction(v, m, uintptr(n), fp, args, uintptr(len(self)), argPtrs, localPtrs)
/* reference as a slice */
s := *(*[]byte)(unsafe.Pointer(&reflect.SliceHeader {
Data : m,
Cap : n,
Len : len(self),
}))
/* copy the machine code, and make it executable */
copy(s, self)
mprotect(m, n)
return Function(&m)
}
func mmap(nb int) uintptr {
if m, _, e := syscall.RawSyscall6(syscall.SYS_MMAP, 0, uintptr(nb), _RW, _AP, 0, 0); e != 0 {
panic(e)
} else {
return m
}
}
func mprotect(p uintptr, nb int) {
if _, _, err := syscall.RawSyscall(syscall.SYS_MPROTECT, p, uintptr(nb), _RX); err != 0 {
panic(err)
}
}
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