Re: [Xen-devel] [PATCH v3 14/23] libxl: info: Display build_id of the hypervisor.

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Fri, Feb 12, 2016 at 01:05:52PM -0500, Konrad Rzeszutek Wilk wrote:
> If the hypervisor is built with we will display it.
> 
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> ---
> v2: Include HAVE_*, use libxl_zalloc, s/rc/ret/
> v3: Retry with different size if 1020 is not enough.
> ---
>  tools/libxl/libxl.c         | 45 
> +++++++++++++++++++++++++++++++++++++++++++++
>  tools/libxl/libxl.h         |  5 +++++
>  tools/libxl/libxl_types.idl |  1 +
>  tools/libxl/xl_cmdimpl.c    |  1 +
>  4 files changed, 52 insertions(+)
> 
> diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
> index 2d18b8d..4efd8dd 100644
> --- a/tools/libxl/libxl.c
> +++ b/tools/libxl/libxl.c
> @@ -5256,6 +5256,38 @@ libxl_numainfo *libxl_get_numainfo(libxl_ctx *ctx, int 
> *nr)
>      return ret;
>  }
>  
> +static const int libxl_get_build_id(libxl_ctx *ctx, libxl_version_info *info,
> +                                    xen_build_id_t *build)

Is this supposed to be a public API? If not, please make it

   libxl__get_build_id(libxl__gc *gc, ...)

.

Asking because it only gets used in libxl_get_version_info.

> +{
> +    GC_INIT(ctx);
> +    int ret;
> +
> +    ret = xc_version(ctx->xch, XENVER_build_id, build);
> +    switch ( ret ) {
> +    case -EPERM:
> +    case -ENODATA:
> +    case 0:
> +        info->build_id = libxl__strdup(NOGC, "");
> +        break;
> +    case -ENOBUFS:
> +        GC_FREE;
> +        return -ENOBUFS;

The error code should be libxl error ERROR_*.

> +    default:
> +        if (ret > 0) {
> +            unsigned int i;
> +
> +            info->build_id = libxl__zalloc(NOGC, (ret * 2) + 1);
> +
> +            for (i = 0; i < ret ; i++)
> +                snprintf(&info->build_id[i * 2], 3, "%02hhx", build->buf[i]);
> +        } else
> +            LOGEV(ERROR, ret, "getting build_id");
> +        break;
> +    }
> +    GC_FREE;
> +    return 0;

Please use goto out style error handling.

See CODING_STYLE and existing functions for reference.

> +}
> +
>  const libxl_version_info* libxl_get_version_info(libxl_ctx *ctx)
>  {
>      GC_INIT(ctx);
> @@ -5266,8 +5298,10 @@ const libxl_version_info* 
> libxl_get_version_info(libxl_ctx *ctx)
>          xen_capabilities_info_t xen_caps;
>          xen_platform_parameters_t p_parms;
>          xen_commandline_t xen_commandline;
> +        xen_build_id_t build_id;
>      } u;
>      long xen_version;
> +    int ret;

Normally this is called rc. See CODING_STYLE.

>      libxl_version_info *info = &ctx->version_info;
>  
>      if (info->xen_version_extra != NULL)
> @@ -5300,6 +5334,17 @@ const libxl_version_info* 
> libxl_get_version_info(libxl_ctx *ctx)
>      xc_version(ctx->xch, XENVER_commandline, &u.xen_commandline);
>      info->commandline = libxl__strdup(NOGC, u.xen_commandline);
>  
> +    u.build_id.len = sizeof(u) - sizeof(u.build_id);
> +    ret = libxl_get_build_id(ctx, info, &u.build_id);
> +    if ( ret == -ENOBUFS ) {

No space in after "(" and before ")".

> +            xen_build_id_t *build_id;
> +
> +            build_id = libxl__zalloc(gc, info->pagesize);
> +            build_id->len = info->pagesize - sizeof(*build_id);
> +            ret = libxl_get_build_id(ctx, info, build_id);
> +            if ( ret )
> +                LOGEV(ERROR, ret, "getting build_id");
> +    }
>   out:
>      GC_FREE;
>      return info;
> diff --git a/tools/libxl/libxl.h b/tools/libxl/libxl.h
> index fa87f53..b713407 100644
> --- a/tools/libxl/libxl.h
> +++ b/tools/libxl/libxl.h
> @@ -218,6 +218,11 @@
>  #define LIBXL_HAVE_SOFT_RESET 1
>  
>  /*
> + * LIBXL_HAVE_BUILD_ID means that libxl_version_info has the extra
> + * field for the hypervisor build_id.
> + */
> +#define LIBXL_HAVE_BUILD_ID 1
> +/*
>   * libxl ABI compatibility
>   *
>   * The only guarantee which libxl makes regarding ABI compatibility
> diff --git a/tools/libxl/libxl_types.idl b/tools/libxl/libxl_types.idl
> index 9ad7eba..92bf620 100644
> --- a/tools/libxl/libxl_types.idl
> +++ b/tools/libxl/libxl_types.idl
> @@ -356,6 +356,7 @@ libxl_version_info = Struct("version_info", [
>      ("virt_start",        uint64),
>      ("pagesize",          integer),
>      ("commandline",       string),
> +    ("build_id",          string),
>      ], dir=DIR_OUT)
>  
>  libxl_domain_create_info = Struct("domain_create_info",[
> diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
> index d07ccb2..9bdc42a 100644
> --- a/tools/libxl/xl_cmdimpl.c
> +++ b/tools/libxl/xl_cmdimpl.c
> @@ -5552,6 +5552,7 @@ static void output_xeninfo(void)
>      printf("cc_compile_by          : %s\n", info->compile_by);
>      printf("cc_compile_domain      : %s\n", info->compile_domain);
>      printf("cc_compile_date        : %s\n", info->compile_date);
> +    printf("build_id               : %s\n", info->build_id);
>  
>      return;
>  }
> -- 
> 2.1.0
> 

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