[Xen-devel] [PATCH] libxc: check in xc_get_tot_pages() that the proper domain is reported

[Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>]

XEN_DOMCTL_getdomaininfo, which is being used by xc_domain_getinfo(), has
strange interface: it reports first domain which has domid >= requested domid
so all callers are supposed to check that the proper domain(s) was queried
by checking domid. xc_get_tot_pages() doesn't do that. In case the requested
domain was destroyed it will report first domain with domid > requested domid
which is apparently misleading as there is no way xc_get_tot_pages() callers
can figure out that they got tot_pages for some other domain.

Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
---
 tools/libxc/xc_private.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/tools/libxc/xc_private.c b/tools/libxc/xc_private.c
index 1c214dd..e2441ad 100644
--- a/tools/libxc/xc_private.c
+++ b/tools/libxc/xc_private.c
@@ -613,8 +613,10 @@ int xc_get_pfn_list(xc_interface *xch,
 long xc_get_tot_pages(xc_interface *xch, uint32_t domid)
 {
     xc_dominfo_t info;
-    return (xc_domain_getinfo(xch, domid, 1, &info) != 1) ?
-        -1 : info.nr_pages;
+    if ( (xc_domain_getinfo(xch, domid, 1, &info) != 1) ||
+         (info.domid != domid) )
+        return -1;
+    return info.nr_pages;
 }
 
 int xc_copy_to_domain_page(xc_interface *xch,
-- 
1.9.3


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