92 lines
1.6 KiB
Go
92 lines
1.6 KiB
Go
package main
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import (
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"fmt"
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"os"
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"syscall"
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"time"
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)
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const (
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testFile = "symlink_race.test_file"
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testFileTmp = testFile + ".tmp"
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)
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func renameLoop() {
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// May be left behind from an earlier run
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syscall.Unlink(testFileTmp)
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var err error
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var fd *os.File
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for {
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err = syscall.Symlink("/root/chmod_me", testFileTmp)
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if err != nil {
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fmt.Printf("Symlink() failed: %v\n", err)
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continue
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}
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err = syscall.Rename(testFileTmp, testFile)
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if err != nil {
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fmt.Printf("Rename() 1 failed: %v\n", err)
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continue
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}
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fd, err = os.Create(testFileTmp)
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if err != nil {
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fmt.Printf("Create() failed: %v\n", err)
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continue
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}
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fd.Close()
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err = syscall.Rename(testFileTmp, testFile)
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if err != nil {
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fmt.Printf("Rename() 2 failed: %v\n", err)
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continue
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}
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fmt.Printf(".")
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}
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}
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func chmodLoop() {
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var err error
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for {
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err = syscall.Chmod(testFile, 0777)
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if err != nil {
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fmt.Printf("Chmod() failed: %v\n", err)
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} else {
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fmt.Printf("Chmod() ok\n")
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}
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time.Sleep(100 * time.Microsecond)
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}
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}
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func openLoop() {
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var err error
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var f *os.File
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buf := make([]byte, 100)
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owned := []byte("owned")
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var n int
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for {
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f, err = os.OpenFile(testFile, os.O_RDWR, 0777)
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if err != nil {
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fmt.Printf("Open() failed: %v\n", err)
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continue
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}
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_, err = f.Write(owned)
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if err != nil {
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fmt.Printf("Write() failed: %v\n", err)
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}
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n, err = f.Read(buf)
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if err != nil {
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fmt.Printf("Read() failed: %v\n", err)
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continue
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}
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if n > 0 {
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fmt.Printf("Content: %q\n", string(buf[:n]))
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os.Exit(1)
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}
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}
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}
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func main() {
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go openLoop()
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renameLoop()
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}
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