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// Copyright 2017 syzkaller project authors. All rights reserved.
// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
//go:build freebsd || netbsd || openbsd || linux || darwin
package osutil
import (
"fmt"
"io"
"os"
"os/signal"
"path/filepath"
"strconv"
"syscall"
)
// ProcessTempDir creates a new temp dir in where and returns its path and an unique index.
// It also cleans up old, unused temp dirs after dead processes.
func ProcessTempDir(where string) (string, error) {
lk := filepath.Join(where, "instance-lock")
lkf, err := syscall.Open(lk, syscall.O_RDWR|syscall.O_CREAT, DefaultFilePerm)
if err != nil {
return "", err
}
defer syscall.Close(lkf)
if err := syscall.Flock(lkf, syscall.LOCK_EX); err != nil {
return "", err
}
defer syscall.Flock(lkf, syscall.LOCK_UN)
for i := 0; i < 1e3; i++ {
path := filepath.Join(where, fmt.Sprintf("instance-%v", i))
pidfile := filepath.Join(path, ".pid")
err := os.Mkdir(path, DefaultDirPerm)
if os.IsExist(err) {
// Try to clean up.
if cleanupTempDir(path, pidfile) {
i--
}
continue
}
if err != nil {
return "", err
}
if err := WriteFile(pidfile, []byte(strconv.Itoa(syscall.Getpid()))); err != nil {
return "", err
}
return path, nil
}
return "", fmt.Errorf("too many live instances")
}
func cleanupTempDir(path, pidfile string) bool {
data, err := os.ReadFile(pidfile)
if err == nil && len(data) > 0 {
pid, err := strconv.Atoi(string(data))
if err == nil && pid > 1 {
if err := syscall.Kill(pid, 0); err == syscall.ESRCH {
if os.Remove(pidfile) == nil {
return os.RemoveAll(path) == nil
}
}
}
}
// If err != nil, assume that the pid file is not created yet.
return false
}
// HandleInterrupts closes shutdown chan on first SIGINT
// (expecting that the program will gracefully shutdown and exit)
// and terminates the process on third SIGINT.
func HandleInterrupts(shutdown chan struct{}) {
go func() {
c := make(chan os.Signal, 3)
signal.Notify(c, syscall.SIGINT, syscall.SIGTERM)
<-c
close(shutdown)
fmt.Fprint(os.Stderr, "SIGINT: shutting down...\n")
<-c
fmt.Fprint(os.Stderr, "SIGINT: shutting down harder...\n")
<-c
fmt.Fprint(os.Stderr, "SIGINT: terminating\n")
os.Exit(int(syscall.SIGINT))
}()
}
func LongPipe() (io.ReadCloser, io.WriteCloser, error) {
r, w, err := os.Pipe()
if err != nil {
return nil, nil, fmt.Errorf("failed to create pipe: %w", err)
}
prolongPipe(r, w)
return r, w, err
}
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