Re: [libvirt] [PATCH v2 00/10] Make loading domains with invalid XML possible

On Wed, Dec 02, 2015 at 04:46:20PM +0800, lhuang wrote: > > > On 12/02/2015 01:35 AM, Martin Kletzander wrote: >> We always had to deal with new parsing errors in a weird way. All of >> them needed to go into functions starting the domains. That messes up >> the code, it's confusing to newcomers and so on. >> >> I once had an idea that we can handle this stuff. We know what >> failed, we have the XML that failed parsing and if the problem is not >> in the domain name nor UUID, we can create a domain object out of that >> as well. This way we are able to do something we weren't with this >> series applied. Example follows. >> >> Assume "dummy" is a domain with invalid XML (I just modified the >> file). Now, just for the purpose of this silly example, let's say we >> allowed domains with archtecture x86_*, but now we've realized that >> x86_64 is the only one we want to allow, but there already is a domain >> defined that has <type arch='x86_256' .../>. With the current master, >> the domain would be lost, so we would need to modify the funstion >> starting the domain (e.g. qemuProcessStart for qemu domain). However, >> with this series, it behaves like this: >> >> # virsh list --all --reason >> Id Name State Reason >> --------------------------------------------------------------- >> - dummy shut off invalid XML >> >> # virsh domstate --reason dummy >> shut off (invalid XML) >> >> # virsh start dummy >> error: Failed to start domain dummy >> error: XML error: domain 'dummy' was not loaded due to an XML error >> (unsupported configuration: Unknown architecture x86_256), please >> redefine it >> >> # VISUAL='sed -i s/x86_256/x86_64/' virsh edit dummy >> Domain dummy XML configuration edited. >> >> # virsh domstate --reason dummy >> shut off (unknown) >> >> # virsh start dummy >> Domain dummy started >> >> This is a logical next step for us to clean and separate parsing and >> starting, getting rid of some old code without sacrifying compatibility >> and maybe generating parser code in the future. >> >> v2: >> - rebased on top of current master (with virdomainobjlist.c) >> - only disallow starting domains with invalid definitions (change >> done in v1), but allow re-defining them >> - add support for "virsh list --reason" to better excercise the >> feature added in this patchset >> >> v1: >> - rebase >> - don't allow starting domains with invalid state >> - >> https://www.redhat.com/archives/libvir-list/2015-November/msg01127.html >> >> RFC: >> https://www.redhat.com/archives/libvir-list/2015-September/msg00698.html >> >> >> >> Martin Kletzander (10): >> conf, virsh: Add new domain shutoff reason >> virsh: Refactor the table output of the list command >> virsh: Add support for list -reason >> qemu: Few whitespace cleanups >> conf: Extract name-parsing into its own function >> conf: Extract UUID parsing into its own function >> conf: Optionally keep domains with invalid XML, but don't allow >> starting them >> qemu: Don't lookup invalid domains unless specified otherwise >> qemu: Prepare basic APIs to handle invalid defs >> qemu: Load domains with invalid XML on start >> >> include/libvirt/libvirt-domain.h | 2 + >> src/bhyve/bhyve_driver.c | 2 + >> src/conf/domain_conf.c | 121 >> +++++++++++++++++++++++++++++++-------- >> src/conf/domain_conf.h | 7 +++ >> src/conf/virdomainobjlist.c | 71 +++++++++++++++++++++-- >> src/conf/virdomainobjlist.h | 1 + >> src/libvirt_private.syms | 1 + >> src/libxl/libxl_driver.c | 3 + >> src/lxc/lxc_driver.c | 3 + >> src/qemu/qemu_driver.c | 64 +++++++++++++++++---- >> src/uml/uml_driver.c | 2 + >> tests/virshtest.c | 30 +++++++--- >> tools/virsh-domain-monitor.c | 60 ++++++++++++------- >> tools/virsh.pod | 5 +- >> 14 files changed, 303 insertions(+), 69 deletions(-) >> >> > > I am glad to see these patches you told me before. > > And i have test your patches and found some problem until now: > > 1. if guest xml have private info, libvirt will output it if xml is > invalid: > > # virsh list --all --reason > Id Name State Reason > ------------------------------------------------------------ > > - test3 shut off invalid XML > > # virsh -r dumpxml test3 > ... > <input type='keyboard' bus='ps3'/> <----wrong place It should be in the same place as it was saved on the disk.

> <graphics type='vnc' port='-1' autoport='yes' listen='127.0.0.1' > passwd='123'> <----show passwd > Oh, that's definitely what's not suppose to happen, but since we cannot parse it, I will just disable the dumpxml for read-only connections.

> 2. vcpucount command output looks strange (small problem :) ): > > # virsh vcpucount test3 > Oh, so my guess was that this happens because virsh calls dumpxml, then searches for the info. But I checked and it calls an API that should be blocked. I'm guessing that happened because of the uuid parsing has gone wrong (below). Anyway, I mentioned the first idea because that can happen with something else and hence the only way how to properly prevent that, is to use different API for invalid domains. I'll try working on that, but this is starting to be bigger and bigger overkill, unfortunately.

Anyway, thanks a lot for testing that and letting me know.

> > 3. hit crash if the guest xml uuid is invalid (delete a number) during > stop daemon: > > > Program terminated with signal 11, Segmentation fault. > #0 0x00007fcbe773af87 in virDomainDefFree (def=0x7fcbc423d980) at > conf/domain_conf.c:2327 > 2327 virDomainGraphicsDefFree(def->graphics[i]); > > Thread 1 (Thread 0x7fcbe835c8c0 (LWP 21589)): > #0 0x00007fcbe773af87 in virDomainDefFree (def=0x7fcbc423d980) at > conf/domain_conf.c:2327 > #1 0x00007fcbe773b903 in virDomainObjDispose (obj=0x7fcbc4235fe0) at > conf/domain_conf.c:2487 > #2 0x00007fcbe76f182b in virObjectUnref (anyobj=<optimized out>) at > util/virobject.c:265 > #3 0x00007fcbe76d0ac9 in virHashFree (table=0x7fcbc412eda0) at > util/virhash.c:318 > #4 0x00007fcbe76f182b in virObjectUnref (anyobj=<optimized out>) at > util/virobject.c:265 > #5 0x00007fcbce85f8cf in qemuStateCleanup () at qemu/qemu_driver.c:1126 > #6 0x00007fcbe779a168 in virStateCleanup () at libvirt.c:815 > #7 0x00007fcbe83f02b1 in main (argc=<optimized out>, argv=<optimized > out>) at libvirtd.c:1619 > > Thanks, > Luyao > > -- > libvir-list mailing list > libvir-list(a)redhat.com > https://www.redhat.com/mailman/listinfo/libvir-list -- libvir-list mailing list libvir-list(a)redhat.com https://www.redhat.com/mailman/listinfo/libvir-list