[PATCH 1/7] tools/libs/store: add get- and set-feature related functions

[Juergen Gross <jgross@xxxxxxxx>]

Add functions for getting and setting Xenstore features to libxenstore:

xs_get_features_supported(): return the features supported by the
running Xenstore implementation as defined in xs_wire.h via the
XENSTORE_SERVER_FEATURE_* macros.

xs_get_features_domain(): return the features offered for a specific
domain.

xs_set_features_domain(): set the features available for a specific
domain.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
 tools/include/xenstore.h         | 13 +++++++++
 tools/libs/store/Makefile        |  2 +-
 tools/libs/store/libxenstore.map |  6 ++++
 tools/libs/store/xs.c            | 49 ++++++++++++++++++++++++++++++++
 4 files changed, 69 insertions(+), 1 deletion(-)

diff --git a/tools/include/xenstore.h b/tools/include/xenstore.h
index a442252849..423422dc50 100644
--- a/tools/include/xenstore.h
+++ b/tools/include/xenstore.h
@@ -264,6 +264,19 @@ bool xs_path_is_subpath(const char *parent, const char 
*child);
  */
 bool xs_is_domain_introduced(struct xs_handle *h, unsigned int domid);
 
+/* Get the features supported by Xenstore.
+ * Returned as a bitmap of XENSTORE_SERVER_FEATURE_* values.
+ */
+bool xs_get_features_supported(struct xs_handle *h, unsigned int *features);
+
+/* Get the features available for a given domain. */
+bool xs_get_features_domain(struct xs_handle *h, unsigned int domid,
+                           unsigned int *features);
+
+/* Set the features available for a given domain. */
+bool xs_set_features_domain(struct xs_handle *h, unsigned int domid,
+                           unsigned int features);
+
 char *xs_control_command(struct xs_handle *h, const char *cmd,
                         void *data, unsigned int len);
 /* Deprecated: use xs_control_command() instead. */
diff --git a/tools/libs/store/Makefile b/tools/libs/store/Makefile
index 0649cf8307..fed43b0008 100644
--- a/tools/libs/store/Makefile
+++ b/tools/libs/store/Makefile
@@ -2,7 +2,7 @@ XEN_ROOT=$(CURDIR)/../../..
 include $(XEN_ROOT)/tools/Rules.mk
 
 MAJOR = 4
-MINOR = 0
+MINOR = 1
 version-script := libxenstore.map
 
 ifeq ($(CONFIG_Linux),y)
diff --git a/tools/libs/store/libxenstore.map b/tools/libs/store/libxenstore.map
index 7e6c7bdd30..cd9df86749 100644
--- a/tools/libs/store/libxenstore.map
+++ b/tools/libs/store/libxenstore.map
@@ -39,3 +39,9 @@ VERS_4.0 {
                xs_strings_to_perms;
        local: *; /* Do not expose anything by default */
 };
+VERS_4.1 {
+       global:
+               xs_get_features_supported;
+               xs_get_features_domain;
+               xs_set_features_domain;
+} VERS_4.0;
diff --git a/tools/libs/store/xs.c b/tools/libs/store/xs.c
index cf3266807f..8f4b90a3cf 100644
--- a/tools/libs/store/xs.c
+++ b/tools/libs/store/xs.c
@@ -1407,6 +1407,55 @@ out:
        return port;
 }
 
+static bool xs_uint(char *reply, unsigned int *uintval)
+{
+       if (!reply)
+               return false;
+
+       *uintval = strtoul(reply, NULL, 10);
+       free(reply);
+
+       return true;
+}
+
+bool xs_get_features_supported(struct xs_handle *h, unsigned int *features)
+{
+       struct xsd_sockmsg msg = { .type = XS_GET_FEATURE };
+       struct iovec iov[1];
+
+       iov[0].iov_base = &msg;
+       iov[0].iov_len  = sizeof(msg);
+
+       return xs_uint(xs_talkv(h, iov, ARRAY_SIZE(iov), NULL), features);
+}
+
+bool xs_get_features_domain(struct xs_handle *h, unsigned int domid,
+                           unsigned int *features)
+{
+       return xs_uint(single_with_domid(h, XS_GET_FEATURE, domid), features);
+}
+
+bool xs_set_features_domain(struct xs_handle *h, unsigned int domid,
+                           unsigned int features)
+{
+       struct xsd_sockmsg msg = { .type = XS_SET_FEATURE };
+       char domid_str[MAX_STRLEN(domid)];
+       char feat_str[MAX_STRLEN(features)];
+       struct iovec iov[3];
+
+       snprintf(domid_str, sizeof(domid_str), "%u", domid);
+       snprintf(feat_str, sizeof(feat_str), "%u", features);
+
+       iov[0].iov_base = &msg;
+       iov[0].iov_len  = sizeof(msg);
+       iov[1].iov_base = domid_str;
+       iov[1].iov_len  = strlen(domid_str) + 1;
+       iov[2].iov_base = feat_str;
+       iov[2].iov_len  = strlen(feat_str) + 1;
+
+       return xs_bool(xs_talkv(h, iov, ARRAY_SIZE(iov), NULL));
+}
+
 char *xs_control_command(struct xs_handle *h, const char *cmd,
                         void *data, unsigned int len)
 {
-- 
2.43.0