[Xen-devel] [PATCH RFC 08/14] libxl: Check xc_domain_maximum_gpfn for negative return values

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

Instead of assuming everything is always OK.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
---
 tools/libxc/xc_core_arm.c    | 14 +++++++++++---
 tools/libxc/xc_core_x86.c    | 21 +++++++++++++++++----
 tools/libxc/xc_domain_save.c |  8 +++++++-
 3 files changed, 35 insertions(+), 8 deletions(-)

diff --git a/tools/libxc/xc_core_arm.c b/tools/libxc/xc_core_arm.c
index 888a3ac..88f7ce1 100644
--- a/tools/libxc/xc_core_arm.c
+++ b/tools/libxc/xc_core_arm.c
@@ -31,9 +31,13 @@ xc_core_arch_gpfn_may_present(struct xc_core_arch_context 
*arch_ctxt,
 }
 
 
-static int nr_gpfns(xc_interface *xch, domid_t domid)
+static int nr_gpfns(xc_interface *xch, domid_t domid, int *rc)
 {
-    return xc_domain_maximum_gpfn(xch, domid) + 1;
+    *rc = xc_domain_maximum_gpfn(xch, domid);
+
+    if ( *rc < 0 )
+        return 0;
+    return *rc + 1;
 }
 
 int
@@ -48,9 +52,13 @@ xc_core_arch_memory_map_get(xc_interface *xch, struct 
xc_core_arch_context *unus
                             xc_core_memory_map_t **mapp,
                             unsigned int *nr_entries)
 {
-    unsigned long p2m_size = nr_gpfns(xch, info->domid);
+    int rc;
+    unsigned long p2m_size = nr_gpfns(xch, info->domid, &rc);
     xc_core_memory_map_t *map;
 
+    if ( rc < 0 )
+        return -1;
+
     map = malloc(sizeof(*map));
     if ( map == NULL )
     {
diff --git a/tools/libxc/xc_core_x86.c b/tools/libxc/xc_core_x86.c
index 37b8522..f46468d 100644
--- a/tools/libxc/xc_core_x86.c
+++ b/tools/libxc/xc_core_x86.c
@@ -36,9 +36,13 @@ xc_core_arch_gpfn_may_present(struct xc_core_arch_context 
*arch_ctxt,
 }
 
 
-static int nr_gpfns(xc_interface *xch, domid_t domid)
+static int nr_gpfns(xc_interface *xch, domid_t domid, int *rc)
 {
-    return xc_domain_maximum_gpfn(xch, domid) + 1;
+    *rc = xc_domain_maximum_gpfn(xch, domid);
+
+    if ( *rc < 0 )
+        return 0;
+    return *rc + 1;
 }
 
 int
@@ -53,9 +57,13 @@ xc_core_arch_memory_map_get(xc_interface *xch, struct 
xc_core_arch_context *unus
                             xc_core_memory_map_t **mapp,
                             unsigned int *nr_entries)
 {
-    unsigned long p2m_size = nr_gpfns(xch, info->domid);
+    int rc;
+    unsigned long p2m_size = nr_gpfns(xch, info->domid, &rc);
     xc_core_memory_map_t *map;
 
+    if ( rc < 0 )
+        return -1;
+
     map = malloc(sizeof(*map));
     if ( map == NULL )
     {
@@ -89,7 +97,12 @@ xc_core_arch_map_p2m_rw(xc_interface *xch, struct 
domain_info_context *dinfo, xc
     int err;
     int i;
 
-    dinfo->p2m_size = nr_gpfns(xch, info->domid);
+    dinfo->p2m_size = nr_gpfns(xch, info->domid, &err);
+    if ( err < 0 )
+    {
+        ERROR("nr_gpfns returns errno: %d.", errno);
+        goto out;
+    }
     if ( dinfo->p2m_size < info->nr_pages  )
     {
         ERROR("p2m_size < nr_pages -1 (%lx < %lx", dinfo->p2m_size, 
info->nr_pages - 1);
diff --git a/tools/libxc/xc_domain_save.c b/tools/libxc/xc_domain_save.c
index 254fdb3..6346c12 100644
--- a/tools/libxc/xc_domain_save.c
+++ b/tools/libxc/xc_domain_save.c
@@ -939,7 +939,13 @@ int xc_domain_save(xc_interface *xch, int io_fd, uint32_t 
dom, uint32_t max_iter
     }
 
     /* Get the size of the P2M table */
-    dinfo->p2m_size = xc_domain_maximum_gpfn(xch, dom) + 1;
+    rc = xc_domain_maximum_gpfn(xch, dom);
+    if ( rc < 0 )
+    {
+        ERROR("Could not get maximum GPFN!");
+        goto out;
+    }
+    dinfo->p2m_size = rc + 1;
 
     if ( dinfo->p2m_size > ~XEN_DOMCTL_PFINFO_LTAB_MASK )
     {
-- 
2.1.0


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