btrfs-test.go

btrfs-test.go

// +build linux

package main

/*
#include <stdlib.h>
#include <dirent.h>
#include <btrfs/ioctl.h>
*/
import "C"
import (
	"fmt"
	"syscall"
	"unsafe"
)

const (
	BTRFS_ROOT_REF_KEY  = 156
	BTRFS_ROOT_ITEM_KEY = 132
)

func free(p *C.char) {
	C.free(unsafe.Pointer(p))
}

func openDir(path string) (*C.DIR, error) {
	Cpath := C.CString(path)
	defer free(Cpath)

	dir := C.opendir(Cpath)
	if dir == nil {
		return nil, fmt.Errorf("Can't open dir")
	}
	return dir, nil
}

func closeDir(dir *C.DIR) {
	if dir != nil {
		C.closedir(dir)
	}
}

func getDirFd(dir *C.DIR) uintptr {
	return uintptr(C.dirfd(dir))
}

func main() {
	//var name string
	var path string = "/var/lib/docker/"
	//var id string = "8596"
	var args C.struct_btrfs_ioctl_search_args
	//for i, c := range []byte(name) {
	//	args[i] = C.char(c)
	//}

	var u64 uint64
	sk := args.key
	sk.max_type = BTRFS_ROOT_REF_KEY
	sk.min_type = BTRFS_ROOT_ITEM_KEY
	sk.min_objectid = 0
	sk.max_objectid = C.__u64(u64 - 1)
	sk.max_offset = C.__u64(u64 - 1)
	sk.min_offset = 0
	sk.max_transid = C.__u64(u64 - 1)
	sk.nr_items = 4096

	dir, err := openDir(path)
	if err != nil {
		fmt.Errorf("Can't open dir %s: %v", path, err)
	}
	defer closeDir(dir)
	_, _, errno := syscall.Syscall(syscall.SYS_IOCTL, getDirFd(dir), C.BTRFS_IOC_TREE_SEARCH, uintptr(unsafe.Pointer(&args)))
	if errno < 0 {
		fmt.Errorf("Can't perform the search under %s", path)
	}

	if sk.nr_items == 0 {
		fmt.Println("nr_items was 0")
		return
	}

	//off := 0
	//for i = 0; i < sk.nr_items; i++ {

	//}

	fmt.Printf("%#v", sk)

	fmt.Printf("%#v", args.buf)

}