Bug 1379585

Summary:	guestfish mistakely parse nbd exportname
Product:	[Community] Virtualization Tools	Reporter:	Han Han <hhan>
Component:	libguestfs	Assignee:	Richard W.M. Jones <rjones>
Status:	CLOSED UPSTREAM	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	medium	Docs Contact:
Priority:	unspecified
Version:	unspecified	CC:	dyuan, mbooth, mxie, ptoscano, rjones, tzheng, virt-bugs, virt-maint, xuzhang
Target Milestone:	---
Target Release:	---
Hardware:	x86_64
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:	1379579	Environment:
Last Closed:	2020-08-17 11:18:06 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Bug Depends On:
Bug Blocks:	1379579

Description Han Han 2016-09-27 07:43:41 UTC

+++ This bug was initially created as a clone of Bug #1379579 +++

Description of problem:
As subject

Version-Release number of selected component (if applicable):
qemu-kvm-2.7.0-1.fc26.x86_64
libvirt-2.2.0-1.fc26.x86_64
libguestfs-tools-c-1.35.6-1.fc26.x86_64


How reproducible:
100%

Steps to Reproduce:
1. Using nbdkit to setup a nbd server with exportname 'image':
# nbdkit file -n -e image file=V.qcow2

2. Try to read the image via guestfish
# qemu-img info nbd://xx.xx.xx.xx:10809/image            
image: nbd://xx.xx.xx.xx:10809/image
file format: qcow2
virtual size: 3.0G (3221225472 bytes)
disk size: unavailable
cluster_size: 65536
Format specific information:
    compat: 1.1
    lazy refcounts: false
    refcount bits: 16
    corrupt: false
# guestfish --ro --format=qcow2 -a nbd://xx.xx.xx.xx:10809/image
libguestfs: trace: set_verbose true
libguestfs: trace: set_verbose = 0
libguestfs: create: flags = 0, handle = 0x7fb2bc712fc0, program = guestfish
libguestfs: trace: set_pgroup true
libguestfs: trace: set_pgroup = 0
libguestfs: trace: add_drive "/image" "readonly:true" "format:qcow2" "protocol:nbd" "server:tcp:xx.xx.xx.xx:10809"
libguestfs: creating COW overlay to protect original drive content
libguestfs: trace: get_tmpdir
libguestfs: trace: get_tmpdir = "/tmp"
libguestfs: trace: disk_create "/tmp/libguestfsPImcnO/overlay1" "qcow2" -1 "backingfile:nbd:xx.xx.xx.xx:10809:exportname=/image" "backingformat:qcow2"
libguestfs: command: run: qemu-img
libguestfs: command: run: \ create
libguestfs: command: run: \ -f qcow2
libguestfs: command: run: \ -o backing_file=nbd:xx.xx.xx.xx:10809:exportname=/image,backing_fmt=qcow2
libguestfs: command: run: \ /tmp/libguestfsPImcnO/overlay1
qemu-img: /tmp/libguestfsPImcnO/overlay1: No export with name '/image' available
libguestfs: error: qemu-img: /tmp/libguestfsPImcnO/overlay1: qemu-img exited with error status 1, see debug messages above
libguestfs: trace: disk_create = -1 (error)
libguestfs: trace: add_drive = -1 (error)
libguestfs: trace: close
libguestfs: closing guestfs handle 0x7fb2bc712fc0 (state 0)
libguestfs: command: run: rm
libguestfs: command: run: \ -rf /tmp/libguestfsPImcnO


Actual results:
As above

Expected results:
Parse exportname as 'image', not '/image'.

Comment 1 Pino Toscano 2016-09-27 09:22:10 UTC

Patch posted:
https://www.redhat.com/archives/libguestfs/2016-September/msg00181.html

Comment 2 Richard W.M. Jones 2016-10-31 16:33:30 UTC

I'm somewhat unconvinced this is a real bug, nor that breaking
all existing guestfish users is worthwhile.  Note that the
current behaviour is documented in the manual page, which is
usually our gold standard for what we shouldn't break.

You can just use the longer 'add-drive' command if you want
to specify export names which don't begin with a '/'.

I suppose an alternative might be to allow an optional
?exportname=... parameter for the (guestfish) URL.

Comment 3 Richard W.M. Jones 2017-02-16 14:57:32 UTC

*** Bug 1379579 has been marked as a duplicate of this bug. ***

Comment 4 Pino Toscano 2020-08-17 11:18:06 UTC

Fast forward four years, the rejected patch was committed upstream (without a couple of extra tests my version had):
https://github.com/libguestfs/libguestfs/commit/bd3fb6535106847edbe340f9413ad43d4be03005

It will be in libguestfs >= 1.43.2.

Comment 5 Richard W.M. Jones 2020-08-17 11:57:57 UTC

Oh sorry, I didn't realise there was a bug for this and you'd already
suggested roughly the same patch.  (What did change is there's now a standard
for NBD URIs).  Do you want to push your two extra hunks on top, with
a note pointing to this BZ?