68 lines
1.2 KiB
Go
68 lines
1.2 KiB
Go
//go:build unix
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package mem
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import (
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"syscall"
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"unsafe"
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)
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func reserve(total_address_space uintptr) ([]byte, error) {
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data, err := syscall.Mmap(-1, 0, int(total_address_space), syscall.PROT_NONE, syscall.MAP_PRIVATE|syscall.MAP_ANON)
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if err != nil {
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return nil, err
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}
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return data, nil
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}
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func release(reserved []byte) error {
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return syscall.Munmap(reserved)
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}
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func commit(reserved []byte, access Access) error {
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return syscall.Mprotect(reserved, access_to_prot(access))
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}
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func decommit(committed []byte) (err error) {
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err = syscall.Mprotect(committed, syscall.PROT_NONE)
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if err != nil {
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return
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}
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return madvise(committed, syscall.MADV_DONTNEED)
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}
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var _zero uintptr
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func madvise(b []byte, advice int) (err error) {
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var _p0 unsafe.Pointer
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if len(b) > 0 {
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_p0 = unsafe.Pointer(&b[0])
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} else {
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_p0 = unsafe.Pointer(&_zero)
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}
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_, _, e := syscall.Syscall(syscall.SYS_MADVISE, uintptr(_p0), uintptr(len(b)), uintptr(advice))
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if e != 0 {
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err = syscall.Errno(e)
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}
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return
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}
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func access_to_prot(access Access) (prot int) {
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prot = syscall.PROT_NONE
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if access&AccessRead != 0 {
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prot |= syscall.PROT_READ
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}
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if access&AccessWrite != 0 {
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prot |= syscall.PROT_WRITE
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}
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if access&AccessExecute != 0 {
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prot |= syscall.PROT_EXEC
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}
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return
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}
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