On Wed, 2015-11-11 at 16:18 +0000, Paul Durrant wrote:
> As documented in docs/misc/xenstore, the XS_MKDIR operation merely makes
> sure a path exists whereas ~/control/shutdown needs to start empty. Also
> using XS_MKDIR for a node which is never supposed to have children is
> somewhat counterintuitive.
>
> This patch introduces a new libxl__xs_printf_perms() function analogous
> to libxl__xs_printf() but taking explicit permissions arguments, and then
> uses this to create an empty ~/control/shutdown node.
>
> Signed-off-by: Paul Durrant <paul.durr...@citrix.com>
> Cc: Ian Jackson <ian.jack...@eu.citrix.com>
> Cc: Stefano Stabellini <stefano.stabell...@eu.citrix.com>
> Cc: Ian Campbell <ian.campb...@citrix.com>
> Cc: Wei Liu <wei.l...@citrix.com>
> ---
> tools/libxl/libxl_create.c | 16 ++++++++++------
> tools/libxl/libxl_internal.h | 10 ++++++++++
> tools/libxl/libxl_xshelp.c | 44
> ++++++++++++++++++++++++++++++++++++++------
> 3 files changed, 58 insertions(+), 12 deletions(-)
>
> diff --git a/tools/libxl/libxl_create.c b/tools/libxl/libxl_create.c
> index 921d155..279deda 100644
> --- a/tools/libxl/libxl_create.c
> +++ b/tools/libxl/libxl_create.c
> @@ -484,7 +484,7 @@ int libxl__domain_make(libxl__gc *gc,
> libxl_domain_config *d_config,
> libxl_ctx *ctx = libxl__gc_owner(gc);
> int flags, ret, rc, nb_vm;
> char *uuid_string;
> - char *dom_path, *vm_path, *libxl_path;
> + char *dom_path, *vm_path, *libxl_path, *control_path;
> struct xs_permissions roperm[2];
> struct xs_permissions rwperm[1];
> struct xs_permissions noperm[1];
> @@ -605,17 +605,21 @@ retry_transaction:
> libxl__xs_mkdir(gc, t,
> libxl__sprintf(gc, "%s/device", dom_path),
> roperm, ARRAY_SIZE(roperm));
> - libxl__xs_mkdir(gc, t,
> - libxl__sprintf(gc, "%s/control", dom_path),
> +
> + control_path = libxl__sprintf(gc, "%s/control", dom_path);
> +
> + libxl__xs_mkdir(gc, t, control_path,
> roperm, ARRAY_SIZE(roperm));
> if (info->type == LIBXL_DOMAIN_TYPE_HVM)
> libxl__xs_mkdir(gc, t,
> libxl__sprintf(gc, "%s/hvmloader", dom_path),
> roperm, ARRAY_SIZE(roperm));
>
> - libxl__xs_mkdir(gc, t,
> - libxl__sprintf(gc, "%s/control/shutdown", dom_path),
> - rwperm, ARRAY_SIZE(rwperm));
> + libxl__xs_printf_perms(gc, t,
> + libxl__sprintf(gc, "%s/shutdown",
> control_path),
> + rwperm, ARRAY_SIZE(rwperm),
> + "");
> +
> libxl__xs_mkdir(gc, t,
> libxl__sprintf(gc, "%s/device/suspend/event-
> channel", dom_path),
> rwperm, ARRAY_SIZE(rwperm));
> diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
> index 4710804..04d8a29 100644
> --- a/tools/libxl/libxl_internal.h
> +++ b/tools/libxl/libxl_internal.h
> @@ -666,6 +666,16 @@ _hidden int libxl__xs_writev_perms(libxl__gc *gc,
> xs_transaction_t t,
> _hidden int libxl__xs_writev_atonce(libxl__gc *gc,
> const char *dir, char **kvs);
>
> +_hidden int libxl__xs_vprintf_perms(libxl__gc *gc, xs_transaction_t t,
> + const char *path,
> + struct xs_permissions *perms,
> + unsigned int num_perms,
> + const char *fmt, va_list ap);
> +_hidden int libxl__xs_printf_perms(libxl__gc *gc, xs_transaction_t t,
> + const char *path,
> + struct xs_permissions *perms,
> + unsigned int num_perms,
> + const char *fmt, ...)
> PRINTF_ATTRIBUTE(6, 7);
> _hidden int libxl__xs_printf(libxl__gc *gc, xs_transaction_t t,
> const char *path, const char *fmt, ...)
> PRINTF_ATTRIBUTE(4, 5);
> /* Each fn returns 0 on success.
> diff --git a/tools/libxl/libxl_xshelp.c b/tools/libxl/libxl_xshelp.c
> index 3cac4f2..0b56f8b 100644
> --- a/tools/libxl/libxl_xshelp.c
> +++ b/tools/libxl/libxl_xshelp.c
> @@ -96,25 +96,57 @@ out:
>
> }
>
> -int libxl__xs_printf(libxl__gc *gc, xs_transaction_t t,
> - const char *path, const char *fmt, ...)
> +int libxl__xs_vprintf_perms(libxl__gc *gc, xs_transaction_t t,
> + const char *path,
> + struct xs_permissions *perms,
> + unsigned int num_perms,
> + const char *fmt,
> + va_list ap)
> {
> libxl_ctx *ctx = libxl__gc_owner(gc);
> char *s;
> - va_list ap;
> int ret;
> - va_start(ap, fmt);
> - ret = vasprintf(&s, fmt, ap);
> - va_end(ap);
>
> + ret = vasprintf(&s, fmt, ap);
> if (ret == -1) {
> return -1;
> }
> xs_write(ctx->xsh, t, path, s, ret);
> + if (perms)
> + xs_set_permissions(ctx->xsh, t, path, perms, num_perms);
This can fail, can't it? (OTOH so can xs_write, so maybe there is some
reason we apparently don't care for such things here?)
> free(s);
> return 0;
> }
>
> +int libxl__xs_printf_perms(libxl__gc *gc, xs_transaction_t t,
> + const char *path,
> + struct xs_permissions *perms,
> + unsigned int num_perms,
> + const char *fmt, ...)
> +{
> + va_list ap;
> + int ret;
> +
> + va_start(ap, fmt);
> + ret = libxl__xs_vprintf_perms(gc, t, path, perms, num_perms, fmt,
> ap);
> + va_end(ap);
> +
> + return ret;
> +}
> +
> +int libxl__xs_printf(libxl__gc *gc, xs_transaction_t t,
> + const char *path, const char *fmt, ...)
> +{
> + va_list ap;
> + int ret;
> +
> + va_start(ap, fmt);
> + ret = libxl__xs_vprintf_perms(gc, t, path, NULL, 0, fmt, ap);
> + va_end(ap);
> +
> + return ret;
> +}
> +
> char * libxl__xs_read(libxl__gc *gc, xs_transaction_t t, const char
> *path)
> {
> libxl_ctx *ctx = libxl__gc_owner(gc);
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