52 lines
1.4 KiB
Go
52 lines
1.4 KiB
Go
// Package ensurefds012 ensures that file descriptors 0,1,2 are open. It opens
|
|
// multiple copies of /dev/null as required.
|
|
// The Go stdlib as well as the gocryptfs code rely on the fact that
|
|
// fds 0,1,2 are always open.
|
|
//
|
|
// Use like this:
|
|
//
|
|
// import _ "github.com/rfjakob/gocryptfs/v2/internal/ensurefds012"
|
|
//
|
|
// The import line MUST be in the alphabitcally first source code file of
|
|
// package main!
|
|
//
|
|
// You can test if it works as expected by inserting a long sleep into main,
|
|
// startings gocryptfs with all fds closed like this,
|
|
//
|
|
// $ ./gocryptfs 0<&- 1>&- 2>&-
|
|
//
|
|
// and then checking the open fds. It should look like this:
|
|
//
|
|
// $ ls -l /proc/$(pgrep gocryptfs)/fd
|
|
// total 0
|
|
// lrwx------. 1 jakob jakob 64 Jan 5 15:54 0 -> /dev/null
|
|
// lrwx------. 1 jakob jakob 64 Jan 5 15:54 1 -> /dev/null
|
|
// lrwx------. 1 jakob jakob 64 Jan 5 15:54 2 -> /dev/null
|
|
// l-wx------. 1 jakob jakob 64 Jan 5 15:54 3 -> /dev/null
|
|
// lrwx------. 1 jakob jakob 64 Jan 5 15:54 4 -> 'anon_inode:[eventpoll]'
|
|
//
|
|
// See https://github.com/rfjakob/gocryptfs/issues/320 for details.
|
|
package ensurefds012
|
|
|
|
import (
|
|
"os"
|
|
"syscall"
|
|
|
|
"github.com/rfjakob/gocryptfs/v2/internal/exitcodes"
|
|
)
|
|
|
|
func init() {
|
|
fd, err := syscall.Open("/dev/null", syscall.O_RDWR, 0)
|
|
if err != nil {
|
|
os.Exit(exitcodes.DevNull)
|
|
}
|
|
for fd <= 2 {
|
|
fd, err = syscall.Dup(fd)
|
|
if err != nil {
|
|
os.Exit(exitcodes.DevNull)
|
|
}
|
|
}
|
|
// Close excess fd (usually fd 3)
|
|
syscall.Close(fd)
|
|
}
|