[PATCH] virStorageSourceParseNBDColonString: Rewrite to match what qemu does

[Eric Blake]

On 4/24/20 7:04 AM, Peter Krempa wrote:
> Our implementation wasn't quite able to parse everything that qemu does.
> This patch rewrites the parser to a code that semantically resembles the
> combination of 'nbd_parse_filename' and 'inet_parse' methods in qemu to
> be able to parse the strings in an equivalent manner.
> 
> The only thing that libvirt doesn't do is to check the lenghts of

lengths

> various components in the nbd string in places where qemu uses constant
> size buffers.
> 
> The test cases validate that some of the corner cases involving colons
> are parsed properly.
> 
> https://bugzilla.redhat.com/show_bug.cgi?id=1826652
> 
> Signed-off-by: Peter Krempa <pkrempa at redhat.com>
> ---
>   src/util/virstoragefile.c | 90 +++++++++++++++++++++++----------------
>   tests/virstoragetest.c    | 16 +++++++
>   2 files changed, 70 insertions(+), 36 deletions(-)
> 

> +++ b/tests/virstoragetest.c
> @@ -1261,10 +1261,26 @@ mymain(void)
>                          "<source protocol='nbd' name=':test'>\n"
>                          "  <host name='example.org' port='6000'/>\n"
>                          "</source>\n");
> +    TEST_BACKING_PARSE("nbd:[::1]:6000:exportname=:test",
> +                       "<source protocol='nbd' name=':test'>\n"
> +                       "  <host name='::1' port='6000'/>\n"
> +                       "</source>\n");
> +    TEST_BACKING_PARSE("nbd:127.0.0.1:6000:exportname=:test",
> +                       "<source protocol='nbd' name=':test'>\n"
> +                       "  <host name='127.0.0.1' port='6000'/>\n"
> +                       "</source>\n");

Hideous abuse of both socket name and export name, but I concur that 
fixing libvirt to parse the ugly strings in the same way as qemu is 
worthwhile.  I'd highly recommend anyone thinking of actually doing this 
in practice (rather than just in a QE setup) to use the NBD URI syntax:

nbd://[::1]:6000/:test
nbd://127.0.0.1:6000/:test

>       TEST_BACKING_PARSE("nbd:unix:/tmp/sock:exportname=/",
>                          "<source protocol='nbd' name='/'>\n"
>                          "  <host transport='unix' socket='/tmp/sock'/>\n"
>                          "</source>\n");
> +    TEST_BACKING_PARSE("nbd:unix:/tmp/sock:",
> +                       "<source protocol='nbd'>\n"
> +                       "  <host transport='unix' socket='/tmp/sock:'/>\n"
> +                       "</source>\n");

nbd+unix:///?socket=/tmp/sock:

> +    TEST_BACKING_PARSE("nbd:unix:/tmp/sock::exportname=:",
> +                       "<source protocol='nbd' name=':'>\n"
> +                       "  <host transport='unix' socket='/tmp/sock:'/>\n"
> +                       "</source>\n");

nbd+unix:///:?socket=/tmp/sock:

Whether you also add the proper URI counterparts to the test is not 
directly relevant to the fix at hand.

Reviewed-by: Eric Blake <eblake at redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org