实现基础web服务器

vendor/github.com/bytedance/sonic/internal/loader/loader.go

@@ -0,0 +1,74 @@
+//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)
+    }
+}