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Avoids unnecessary allocations during mmap executables (#1366)

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Signed-off-by: Takeshi Yoneda <takeshi@tetrate.io>
This commit is contained in:
Takeshi Yoneda
2023-04-16 22:03:35 -07:00
committed by GitHub
parent 00d9d885ff
commit d9e5d6b0d3
10 changed files with 65 additions and 93 deletions
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26
internal/platform/mmap_windows.go
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@@ -2,7 +2,6 @@ package platform
import (
"fmt"
"io"
"reflect"
"syscall"
"unsafe"
@@ -58,7 +57,7 @@ func virtualProtect(address, size, newprotect uintptr, oldprotect *uint32) error
return nil
}
func mmapCodeSegmentAMD64(code io.Reader, size int) ([]byte, error) {
func mmapCodeSegmentAMD64(size int) ([]byte, error) {
p, err := allocateMemory(uintptr(size), windows_PAGE_EXECUTE_READWRITE)
if err != nil {
return nil, err
@@ -69,13 +68,10 @@ func mmapCodeSegmentAMD64(code io.Reader, size int) ([]byte, error) {
sh.Data = p
sh.Len = size
sh.Cap = size
w := &bufWriter{underlying: mem}
_, err = io.CopyN(w, code, int64(size))
return mem, err
}
func mmapCodeSegmentARM64(code io.Reader, size int) ([]byte, error) {
func mmapCodeSegmentARM64(size int) ([]byte, error) {
p, err := allocateMemory(uintptr(size), windows_PAGE_READWRITE)
if err != nil {
return nil, err
@@ -86,20 +82,16 @@ func mmapCodeSegmentARM64(code io.Reader, size int) ([]byte, error) {
sh.Data = p
sh.Len = size
sh.Cap = size
w := &bufWriter{underlying: mem}
_, err = io.CopyN(w, code, int64(size))
if err != nil {
return nil, err
}
old := uint32(windows_PAGE_READWRITE)
err = virtualProtect(p, uintptr(size), windows_PAGE_EXECUTE_READ, &old)
if err != nil {
return nil, err
}
return mem, nil
}
var old = uint32(windows_PAGE_READWRITE)
func MprotectRX(b []byte) (err error) {
err = virtualProtect(uintptr(unsafe.Pointer(&b[0])), uintptr(len(b)), windows_PAGE_EXECUTE_READ, &old)
return
}
// ensureErr returns syscall.EINVAL when the input error is nil.
//
// We are supposed to use "GetLastError" which is more precise, but it is not safe to execute in goroutines. While