Quick printer (for glusterfs and github.com/csabahenk/strace-fusedump produced) FUSE dumps

quickparsefuse.go

package main

import (
	"fmt"
	"io"
	"log"
	"os"
	"unsafe"
)

type FuseOpcode int32

const (
	LOOKUP      FuseOpcode = 1
	FORGET      FuseOpcode = 2
	GETATTR     FuseOpcode = 3
	SETATTR     FuseOpcode = 4
	READLINK    FuseOpcode = 5
	SYMLINK     FuseOpcode = 6
	MKNOD       FuseOpcode = 8
	MKDIR       FuseOpcode = 9
	UNLINK      FuseOpcode = 10
	RMDIR       FuseOpcode = 11
	RENAME      FuseOpcode = 12
	LINK        FuseOpcode = 13
	OPEN        FuseOpcode = 14
	READ        FuseOpcode = 15
	WRITE       FuseOpcode = 16
	STATFS      FuseOpcode = 17
	RELEASE     FuseOpcode = 18
	FSYNC       FuseOpcode = 20
	SETXATTR    FuseOpcode = 21
	GETXATTR    FuseOpcode = 22
	LISTXATTR   FuseOpcode = 23
	REMOVEXATTR FuseOpcode = 24
	FLUSH       FuseOpcode = 25
	INIT        FuseOpcode = 26
	OPENDIR     FuseOpcode = 27
	READDIR     FuseOpcode = 28
	RELEASEDIR  FuseOpcode = 29
	FSYNCDIR    FuseOpcode = 30
	GETLK       FuseOpcode = 31
	SETLK       FuseOpcode = 32
	SETLKW      FuseOpcode = 33
	ACCESS      FuseOpcode = 34
	CREATE      FuseOpcode = 35
	INTERRUPT   FuseOpcode = 36
	BMAP        FuseOpcode = 37
	DESTROY     FuseOpcode = 38
	IOCTL       FuseOpcode = 39
	POLL        FuseOpcode = 40
)

var FuseOpnames = [...]string{
	LOOKUP:      "LOOKUP",
	FORGET:      "FORGET",
	GETATTR:     "GETATTR",
	SETATTR:     "SETATTR",
	READLINK:    "READLINK",
	SYMLINK:     "SYMLINK",
	MKNOD:       "MKNOD",
	MKDIR:       "MKDIR",
	UNLINK:      "UNLINK",
	RMDIR:       "RMDIR",
	RENAME:      "RENAME",
	LINK:        "LINK",
	OPEN:        "OPEN",
	READ:        "READ",
	WRITE:       "WRITE",
	STATFS:      "STATFS",
	RELEASE:     "RELEASE",
	FSYNC:       "FSYNC",
	SETXATTR:    "SETXATTR",
	GETXATTR:    "GETXATTR",
	LISTXATTR:   "LISTXATTR",
	REMOVEXATTR: "REMOVEXATTR",
	FLUSH:       "FLUSH",
	INIT:        "INIT",
	OPENDIR:     "OPENDIR",
	READDIR:     "READDIR",
	RELEASEDIR:  "RELEASEDIR",
	FSYNCDIR:    "FSYNCDIR",
	GETLK:       "GETLK",
	SETLK:       "SETLK",
	SETLKW:      "SETLKW",
	ACCESS:      "ACCESS",
	CREATE:      "CREATE",
	INTERRUPT:   "INTERRUPT",
	BMAP:        "BMAP",
	DESTROY:     "DESTROY",
	IOCTL:       "IOCTL",
	POLL:        "POLL",
}

type InHeader struct {
	Length  uint32
	Opcode  FuseOpcode
	Unique  uint64
	NodeId  uint64
	Uid     uint32
	Gid     uint32
	Pid     uint32
	Padding uint32
}

type OutHeader struct {
	Length uint32
	Status int32
	Unique uint64
}

func main() {
	var inh *InHeader
	var ouh *OutHeader

	insize := int(unsafe.Sizeof(*inh))
	outsize := int(unsafe.Sizeof(*ouh))
	if insize <= outsize {
		panic("header size assertion fails")
	}

	buf := make([]byte, insize+1)

	pos := int64(0)
	readgen := func(m, n int, shortcb func(r int)) {
		r, err := os.Stdin.ReadAt(buf[m:n], pos)
		if err == io.EOF {
			err = nil
			r = 0
		}
		if err != nil {
			log.Fatal("Read: ", err)
		}
		if r < n-m {
			shortcb(r)
		}
		pos += int64(r)
	}
	read := func(n int) {
		readgen(0, n, func(r int) {
			if r == 0 {
				os.Exit(0)
			}
			log.Fatal("short read")
		})
	}
	readfrom := func(n int) {
		readgen(n, len(buf), func(r int) { log.Fatal("short read") })
	}

	for {
		ppos := pos
		read(outsize + 1)
		switch buf[0] {
		case 'R':
			readfrom(outsize + 1)
			inh = (*InHeader)(unsafe.Pointer(&buf[1]))
			fmt.Printf("%d %s %+v\n", ppos, FuseOpnames[inh.Opcode], *inh)
			pos = ppos + int64(1) + int64(inh.Length)
		case 'W':
			ouh = (*OutHeader)(unsafe.Pointer(&buf[1]))
			fmt.Printf("%d %+v\n", ppos, *ouh)
			pos = ppos + int64(1) + int64(ouh.Length)
		default:
			log.Fatalf("unknown direction %c", buf[0])
		}
	}
}