libxl: add version_info function

Xen provides a xen_version hypercall to query the values of several
interesting things (like hypervisor version, commandline used, actual
changeset, etc.). Create a user-friendly and efficient wrapper around
the libxc function to provide values for xl info output.
Since the information is static during the whole runtime, we store
it within the libxl_ctx structure and just deliver the pointer on
subsequent calls.

Signed-off-by: Andre Przywara <andre.przywara@amd.com>
Acked-by: Vincent Hanquez <vincent.hanquez@eu.citrix.com>

2 files changed, 64 insertions, 0 deletions

diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index 3db4249a34..7cb3a1caeb 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -45,6 +45,7 @@ int libxl_ctx_init(struct libxl_ctx *ctx, int version)
     ctx->alloc_ptrs = calloc(ctx->alloc_maxsize, sizeof(void *));
     if (!ctx->alloc_ptrs)
         return ERROR_NOMEM;
+    memset(&ctx->version_info, 0, sizeof(libxl_version_info));
 
     ctx->xch = xc_interface_open();
     if (ctx->xch == -1) {
@@ -2351,6 +2352,51 @@ int libxl_get_physinfo(struct libxl_ctx *ctx, struct libxl_physinfo *physinfo)
     return 0;
 }
 
+const libxl_version_info* libxl_get_version_info(struct libxl_ctx *ctx)
+{
+    union {
+        xen_extraversion_t xen_extra;
+        xen_compile_info_t xen_cc;
+        xen_changeset_info_t xen_chgset;
+        xen_capabilities_info_t xen_caps;
+        xen_platform_parameters_t p_parms;
+        xen_commandline_t xen_commandline;
+    } u;
+    long xen_version;
+    libxl_version_info *info = &ctx->version_info;
+
+    if (info->xen_version_extra != NULL)
+        return info;
+
+    xen_version = xc_version(ctx->xch, XENVER_version, NULL);
+    info->xen_version_major = xen_version >> 16;
+    info->xen_version_minor = xen_version & 0xFF;
+    xc_version(ctx->xch, XENVER_extraversion, &u.xen_extra);
+    info->xen_version_extra = libxl_sprintf(ctx, "%s", u.xen_extra);
+
+    xc_version(ctx->xch, XENVER_compile_info, &u.xen_cc);
+    info->compiler = libxl_sprintf(ctx, "%s", u.xen_cc.compiler);
+    info->compile_by = libxl_sprintf(ctx, "%s", u.xen_cc.compile_by);
+    info->compile_domain = libxl_sprintf(ctx, "%s", u.xen_cc.compile_domain);
+    info->compile_date = libxl_sprintf(ctx, "%s", u.xen_cc.compile_date);
+
+    xc_version(ctx->xch, XENVER_capabilities, &u.xen_caps);
+    info->capabilities = libxl_sprintf(ctx, "%s", u.xen_caps);
+
+    xc_version(ctx->xch, XENVER_changeset, &u.xen_chgset);
+    info->changeset = libxl_sprintf(ctx, "%s", u.xen_chgset);
+
+    xc_version(ctx->xch, XENVER_platform_parameters, &u.p_parms);
+    info->virt_start = u.p_parms.virt_start;
+
+    info->pagesize = xc_version(ctx->xch, XENVER_pagesize, NULL);
+
+    xc_version(ctx->xch, XENVER_commandline, &u.xen_commandline);
+    info->commandline = libxl_sprintf(ctx, "%s", u.xen_commandline);
+
+    return info;
+}
+
 struct libxl_vcpuinfo *libxl_list_vcpu(struct libxl_ctx *ctx, uint32_t domid,
                                        int *nb_vcpu, int *cpusize)
 {
diff --git a/tools/libxl/libxl.h b/tools/libxl/libxl.h
index b079613112..0d3b767e65 100644
--- a/tools/libxl/libxl.h
+++ b/tools/libxl/libxl.h
@@ -41,6 +41,21 @@ struct libxl_vminfo {
     uint32_t domid;
 };
 
+typedef struct {
+    int xen_version_major;
+    int xen_version_minor;
+    char *xen_version_extra;
+    char *compiler;
+    char *compile_by;
+    char *compile_domain;
+    char *compile_date;
+    char *capabilities;
+    char *changeset;
+    unsigned long virt_start;
+    unsigned long pagesize;
+    char *commandline;
+} libxl_version_info;
+
 struct libxl_ctx {
     int xch;
     struct xs_handle *xsh;
@@ -56,8 +71,11 @@ struct libxl_ctx {
      * set this after libxl_init and before any other call - or
      * may leave them untouched */
     int (*waitpid_instead)(pid_t pid, int *status, int flags);
+    libxl_version_info version_info;
 };
 
+const libxl_version_info* libxl_get_version_info(struct libxl_ctx *ctx);
+
 typedef struct {
     bool hvm;
     bool hap;