Re: [PATCH 13/13] ssh: add GUri-based URI parsing

["Marc-André Lureau" <marcandre.lureau@gmail.com>]

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Hi

On Thu, Jul 23, 2020 at 4:33 PM Richard W.M. Jones <rjones@redhat.com>
wrote:

> On Thu, Jul 09, 2020 at 11:42:34PM +0400, Marc-André Lureau wrote:
> > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> > ---
> >  block/ssh.c | 75 +++++++++++++++++++++++++++++++++++++++++------------
> >  1 file changed, 58 insertions(+), 17 deletions(-)
> >
> > diff --git a/block/ssh.c b/block/ssh.c
> > index c8f6ad79e3c..d2bc6277613 100644
> > --- a/block/ssh.c
> > +++ b/block/ssh.c
> > @@ -180,9 +180,37 @@ static void sftp_error_trace(BDRVSSHState *s, const
> char *op)
> >
> >  static int parse_uri(const char *filename, QDict *options, Error **errp)
> >  {
> > +    g_autofree char *port_str = NULL;
> > +    const char *scheme, *server, *path, *user, *key, *value;
> > +    gint port;
> > +
> > +#ifdef HAVE_GLIB_GURI
> > +    g_autoptr(GUri) uri = NULL;
> > +    g_autoptr(GHashTable) params = NULL;
> > +    g_autoptr(GError) err = NULL;
> > +    GHashTableIter iter;
> > +
> > +    uri = g_uri_parse(filename, G_URI_FLAGS_ENCODED_QUERY, &err);
> > +    if (!uri) {
> > +        error_setg(errp, "Failed to parse SSH URI: %s", err->message);
> > +        return -EINVAL;
> > +    }
> > +
> > +    params = g_uri_parse_params(g_uri_get_query(uri), -1,
> > +                                "&;", G_URI_PARAMS_NONE, &err);
> > +    if (err) {
> > +        error_report("Failed to parse SSH URI query: %s", err->message);
> > +        return -EINVAL;
> > +    }
> > +
> > +    scheme = g_uri_get_scheme(uri);
> > +    user = g_uri_get_user(uri);
> > +    server = g_uri_get_host(uri);
> > +    path = g_uri_get_path(uri);
> > +    port = g_uri_get_port(uri);
> > +#else
> >      g_autoptr(URI) uri = NULL;
> >      g_autoptr(QueryParams) qp = NULL;
> > -    g_autofree char *port_str = NULL;
> >      int i;
>
> As Dan said already, this conditional code looks horrible and is going
> to be a maintenance burden.  Was there a later version of this patch
> series that resolved this?  I don't think I saw one.
>

The patch is quite experimental. glib didn't even yet receive a release
with GUri! But since I am working on the glib side, I wanted to make sure
it covers qemu needs.

I will revisit the series once GUri is frozen & released (in
mid-september),and use a copy version fallback.

Although, as I said in the cover, this is a bit riskier than having a
transition period with both the old libxml-based parser and glib-based one
for very recent distro.

Tbh, I think having both is not a big burden, because there is very low
activity around those functions. Iow, we are not spreading qemu with a lot
of extra conditionals, but only in very limited mostly static places.


> Rich.
>
>
> >      uri = uri_parse(filename);
> > @@ -190,44 +218,57 @@ static int parse_uri(const char *filename, QDict
> *options, Error **errp)
> >          return -EINVAL;
> >      }
> >
> > -    if (g_strcmp0(uri->scheme, "ssh") != 0) {
> > -        error_setg(errp, "URI scheme must be 'ssh'");
> > +    qp = query_params_parse(uri->query);
> > +    if (!qp) {
> > +        error_setg(errp, "could not parse query parameters");
> >          return -EINVAL;
> >      }
> >
> > -    if (!uri->server || strcmp(uri->server, "") == 0) {
> > -        error_setg(errp, "missing hostname in URI");
> > +    scheme = uri->scheme;
> > +    user = uri->user;
> > +    server = uri->server;
> > +    path = uri->path;
> > +    port = uri->port;
> > +#endif
> > +    if (g_strcmp0(scheme, "ssh") != 0) {
> > +        error_setg(errp, "URI scheme must be 'ssh'");
> >          return -EINVAL;
> >      }
> >
> > -    if (!uri->path || strcmp(uri->path, "") == 0) {
> > -        error_setg(errp, "missing remote path in URI");
> > +    if (!server || strcmp(server, "") == 0) {
> > +        error_setg(errp, "missing hostname in URI");
> >          return -EINVAL;
> >      }
> >
> > -    qp = query_params_parse(uri->query);
> > -    if (!qp) {
> > -        error_setg(errp, "could not parse query parameters");
> > +    if (!path || strcmp(path, "") == 0) {
> > +        error_setg(errp, "missing remote path in URI");
> >          return -EINVAL;
> >      }
> >
> > -    if(uri->user && strcmp(uri->user, "") != 0) {
> > -        qdict_put_str(options, "user", uri->user);
> > +    if (user && strcmp(user, "") != 0) {
> > +        qdict_put_str(options, "user", user);
> >      }
> >
> > -    qdict_put_str(options, "server.host", uri->server);
> > +    qdict_put_str(options, "server.host", server);
> >
> > -    port_str = g_strdup_printf("%d", uri->port ?: 22);
> > +    port_str = g_strdup_printf("%d", port ?: 22);
> >      qdict_put_str(options, "server.port", port_str);
> >
> > -    qdict_put_str(options, "path", uri->path);
> > +    qdict_put_str(options, "path", path);
> >
> >      /* Pick out any query parameters that we understand, and ignore
> >       * the rest.
> >       */
> > +#ifdef HAVE_GLIB_GURI
> > +    g_hash_table_iter_init(&iter, params);
> > +    while (g_hash_table_iter_next(&iter, (void **)&key, (void
> **)&value)) {
> > +#else
> >      for (i = 0; i < qp->n; ++i) {
> > -        if (strcmp(qp->p[i].name, "host_key_check") == 0) {
> > -            qdict_put_str(options, "host_key_check", qp->p[i].value);
> > +        key = qp->p[i].name;
> > +        value = qp->p[i].value;
> > +#endif
> > +        if (g_strcmp0(key, "host_key_check") == 0) {
> > +            qdict_put_str(options, "host_key_check", value);
> >          }
> >      }
> >
> > --
> > 2.27.0.221.ga08a83db2b
>
> --
> Richard Jones, Virtualization Group, Red Hat
> http://people.redhat.com/~rjones
> Read my programming and virtualization blog: http://rwmj.wordpress.com
> libguestfs lets you edit virtual machines.  Supports shell scripting,
> bindings from many languages.  http://libguestfs.org
>
>
>

-- 
Marc-André Lureau

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