37 lines
764 B
Go
37 lines
764 B
Go
// This program increments a given byte of a given file,
|
|
// to test data corruption detection -- BE CAREFUL!
|
|
package main
|
|
|
|
import (
|
|
"fmt"
|
|
"os"
|
|
"strconv"
|
|
)
|
|
|
|
func main() {
|
|
if len(os.Args) != 3 {
|
|
fmt.Println("usage:", os.Args[0], "file offset")
|
|
os.Exit(1)
|
|
}
|
|
f, err := os.OpenFile(os.Args[1], os.O_RDWR, 0644)
|
|
if err != nil {
|
|
fmt.Println("open failed:", err)
|
|
os.Exit(1)
|
|
}
|
|
offset, err := strconv.ParseInt(os.Args[2], 10, 64)
|
|
if err != nil {
|
|
fmt.Println("bad offset:", err)
|
|
os.Exit(1)
|
|
}
|
|
b := make([]byte, 1)
|
|
if n, err := f.ReadAt(b, offset); err != nil || n != 1 {
|
|
fmt.Println("read failed:", n, err)
|
|
os.Exit(1)
|
|
}
|
|
b[0] += 1
|
|
if n, err := f.WriteAt(b, offset); err != nil || n != 1 {
|
|
fmt.Println("read failed:", n, err)
|
|
os.Exit(1)
|
|
}
|
|
}
|