blob: e34182e6264ab4dec430ac50102de793df9758f0 [file] [log] [blame]
// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build linux
// (We only care about Linux on GKE for now)
package main
import (
"log"
"os"
"os/exec"
"os/signal"
"syscall"
)
func init() {
registerSignal = registerSignalUnix
setWorkdirToTmpfs = setWorkdirToTmpfsLinux
}
func registerSignalUnix(c chan<- os.Signal) {
signal.Notify(c, syscall.SIGINT, syscall.SIGTERM)
}
func setWorkdirToTmpfsLinux() {
const dir = "/workdir"
var st syscall.Statfs_t
const TMPFS_MAGIC = 0x01021994 // from statfs(2)
if syscall.Statfs(dir, &st) != nil || st.Type != TMPFS_MAGIC {
return
}
log.Printf("detected tmpfs %s", dir)
const ST_NOEXEC = syscall.MS_NOEXEC // golang.org/issue/25341
if st.Flags&ST_NOEXEC != 0 {
log.Printf("tmpfs %s is noexec; remounting", dir)
out, err := exec.Command("mount", "-o", "remount,exec", dir).CombinedOutput()
if err != nil {
log.Printf("error remounting tmpfs %s as exec: %v, %s", dir, err, out)
return
}
// Check that it worked:
st = syscall.Statfs_t{}
if err := syscall.Statfs(dir, &st); err != nil {
log.Printf("second stat of %s failed after remount: %v", dir, err)
return
}
if st.Flags&ST_NOEXEC != 0 {
log.Printf("remount of %s failed; still marked noexec", dir)
return
}
log.Printf("remounted tmpfs %s to remove noexec", dir)
}
*workDir = dir
log.Printf("using tmpfs %s as workdir.", dir)
}