first commit

ftok.go

@@ -0,0 +1,21 @@
+// Copyright (c) 2020 Meng Huang (mhboy@outlook.com)
+// This package is licensed under a MIT license that can be found in the LICENSE file.
+
+// Package ftok provides a way to generate a System V IPC key, suitable for use with
+// msgget, semget, or shmget.
+package ftok
+
+import (
+	"syscall"
+)
+
+// Ftok uses the given pathname (which must refer to an existing, accessible file) and
+// the least significant 8 bits of proj_id (which must be nonzero) to generate
+// a key_t type System V IPC key.
+func Ftok(pathname string, projectid uint8) (int, error) {
+	var stat = syscall.Stat_t{}
+	if err := syscall.Stat(pathname, &stat); err != nil {
+		return 0, err
+	}
+	return int(uint(projectid&0xff)<<24 | uint((stat.Dev&0xff)<<16) | (uint(stat.Ino) & 0xffff)), nil
+}