Re: [Qemu-devel] [RFC PATCH 1/6] iscsi: Split URL into individual options

["Daniel P. Berrange" <berrange@redhat.com>]

On Thu, Dec 08, 2016 at 02:23:06PM +0100, Kevin Wolf wrote:
> This introduces a .bdrv_parse_filename handler for iscsi which parses an
> URL if given and translates it to individual options.
> 
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>  block/iscsi.c | 189 ++++++++++++++++++++++++++++++++++++++++++----------------
>  1 file changed, 136 insertions(+), 53 deletions(-)
> 
> diff --git a/block/iscsi.c b/block/iscsi.c
> index 0960929..7a6664e 100644
> --- a/block/iscsi.c
> +++ b/block/iscsi.c
> @@ -1469,20 +1469,6 @@ static void iscsi_readcapacity_sync(IscsiLun *iscsilun, Error **errp)
>      }
>  }
>  
> -/* TODO Convert to fine grained options */
> -static QemuOptsList runtime_opts = {
> -    .name = "iscsi",
> -    .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
> -    .desc = {
> -        {
> -            .name = "filename",
> -            .type = QEMU_OPT_STRING,
> -            .help = "URL to the iscsi image",
> -        },
> -        { /* end of list */ }
> -    },
> -};
> -
>  static struct scsi_task *iscsi_do_inquiry(struct iscsi_context *iscsi, int lun,
>                                            int evpd, int pc, void **inq, Error **errp)
>  {
> @@ -1604,20 +1590,98 @@ out:
>   * We support iscsi url's on the form
>   * iscsi://[<username>%<password>@]<host>[:<port>]/<targetname>/<lun>
>   */
> +static void iscsi_parse_filename(const char *filename, QDict *options,
> +                                 Error **errp)
> +{
> +    struct iscsi_url *iscsi_url;
> +    const char *transport_name;
> +    char *lun_str;
> +
> +    iscsi_url = iscsi_parse_full_url(NULL, filename);
> +    if (iscsi_url == NULL) {
> +        error_setg(errp, "Failed to parse URL : %s", filename);
> +        return;
> +    }
> +
> +#if LIBISCSI_API_VERSION >= (20160603)
> +    switch (iscsi_url->transport) {
> +        case TCP_TRANSPORT:     transport_name = "tcp"; break;
> +        case ISER_TRANSPORT:    transport_name = "iser"; break;
> +        default:
> +            error_setg(errp, "Unknown transport type (%d)",
> +                       iscsi_url->transport);
> +            return;
> +    }
> +#else
> +    transport_name = "tcp";
> +#endif

Here if the URI contained a transport "iser" and we're using
an old libiscsi, we silently ignore that and use 'tcp'. IMHO
we should be reporting "Unsupported transport type 'iser'"
when using the old libiscsi API/


> +    qdict_set_default_str(options, "transport", transport_name);
> +    qdict_set_default_str(options, "portal", iscsi_url->portal);
> +    qdict_set_default_str(options, "target", iscsi_url->target);
> +
> +    lun_str = g_strdup_printf("%d", iscsi_url->lun);
> +    qdict_set_default_str(options, "lun", lun_str);
> +    g_free(lun_str);
> +
> +    if (iscsi_url->user[0] != '\0') {
> +        qdict_set_default_str(options, "user", iscsi_url->user);
> +        qdict_set_default_str(options, "password", iscsi_url->passwd);

If the URI contains "user" but not "password", this stores bogus
data in the "password" field I believe.

> +    }
> +
> +    iscsi_destroy_url(iscsi_url);
> +}
> +
> +/* TODO Add -iscsi options */
> +static QemuOptsList runtime_opts = {
> +    .name = "iscsi",
> +    .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
> +    .desc = {
> +        {
> +            .name = "transport",
> +            .type = QEMU_OPT_STRING,
> +        },
> +        {
> +            .name = "portal",
> +            .type = QEMU_OPT_STRING,
> +        },
> +        {
> +            .name = "target",
> +            .type = QEMU_OPT_STRING,
> +        },
> +        {
> +            .name = "user",
> +            .type = QEMU_OPT_STRING,
> +        },
> +        {
> +            .name = "password",
> +            .type = QEMU_OPT_STRING,
> +        },
> +        {
> +            .name = "lun",
> +            .type = QEMU_OPT_NUMBER,
> +        },
> +        { /* end of list */ }
> +    },
> +};
> +
>  static int iscsi_open(BlockDriverState *bs, QDict *options, int flags,
>                        Error **errp)
>  {
>      IscsiLun *iscsilun = bs->opaque;
>      struct iscsi_context *iscsi = NULL;
> -    struct iscsi_url *iscsi_url = NULL;
>      struct scsi_task *task = NULL;
>      struct scsi_inquiry_standard *inq = NULL;
>      struct scsi_inquiry_supported_pages *inq_vpd;
>      char *initiator_name = NULL;
>      QemuOpts *opts;
>      Error *local_err = NULL;
> -    const char *filename;
> -    int i, ret = 0, timeout = 0;
> +    const char *transport_name, *portal, *target;
> +    const char *user, *password;
> +#if LIBISCSI_API_VERSION >= (20160603)
> +    enum iscsi_transport_type transport;
> +#endif
> +    int i, ret = 0, timeout = 0, lun;
>  
>      opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
>      qemu_opts_absorb_qdict(opts, options, &local_err);
> @@ -1627,18 +1691,41 @@ static int iscsi_open(BlockDriverState *bs, QDict *options, int flags,
>          goto out;
>      }
>  
> -    filename = qemu_opt_get(opts, "filename");
> +    transport_name = qemu_opt_get(opts, "transport");
> +    portal = qemu_opt_get(opts, "portal");
> +    target = qemu_opt_get(opts, "target");
> +    user = qemu_opt_get(opts, "user");
> +    password = qemu_opt_get(opts, "password");
> +    lun = qemu_opt_get_number(opts, "lun", 0);

Do we really want to default to '0' for LUN ?  With Linux tgtd at
least this is not a valid LUN to use as a volume. It feels like
we should be raising an error if 'lun' is not explcitly set by
the user

>  
> -    iscsi_url = iscsi_parse_full_url(iscsi, filename);
> -    if (iscsi_url == NULL) {
> -        error_setg(errp, "Failed to parse URL : %s", filename);
> +    if (!transport_name || !portal || !target) {
> +        error_setg(errp, "Need all of transport, portal and target options");
> +        ret = -EINVAL;
> +        goto out;
> +    }
> +    if (user && !password) {
> +        error_setg(errp, "If a user name is given, a password is required");
> +        ret = -EINVAL;
> +        goto out;
> +    }
> +
> +    if (!strcmp(transport_name, "tcp")) {
> +#if LIBISCSI_API_VERSION >= (20160603)
> +        transport = TCP_TRANSPORT;
> +    } else if (!strcmp(transport_name, "iser")) {
> +        transport = ISER_TRANSPORT;
> +#else
> +        /* TCP is what older libiscsi versions always use */

Again we should report an error if user set a transport_name
of 'iser' here.

> +#endif
> +    } else {
> +        error_setg(errp, "Unknown transport: %s", transport_name);
>          ret = -EINVAL;
>          goto out;
>      }
>  
>      memset(iscsilun, 0, sizeof(IscsiLun));


Regards,
Daniel
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