1:06 p.m.
The way our domain capabilities work currently, is that we have
virDomainCapsEnum struct which contains 'unsigned int values'
member which serves as a bitmask. More complicated structs are
composed from this struct, giving us whole virDomainCaps
eventually.
Whenever we want to report that a certain value is supported, the
'1 << value' bit is set in the corresponding unsigned int member.
This works as long as the resulting value after bitshift does not
overflow unsigned int. There is a check inside
virDomainCapsEnumSet() which ensures exactly this, but no caller
really checks whether virDomainCapsEnumSet() succeeded. Also,
checking at runtime is a bit too late.
Fortunately, we know the largest value we want to store in each
member, because each enum of ours ends with _LAST member.
Therefore, we can check at build time whether an overflow can
occur.
Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com>
---
src/conf/domain_capabilities.h | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/src/conf/domain_capabilities.h b/src/conf/domain_capabilities.h
index f177af1744..b22d40abb2 100644
--- a/src/conf/domain_capabilities.h
+++ b/src/conf/domain_capabilities.h
@@ -36,6 +36,9 @@ struct _virDomainCapsEnum {
unsigned int values; /* Bitmask of values supported in the corresponding enum */
};
+#define STATIC_ASSERT_ENUM(last) \
+ G_STATIC_ASSERT(last <= sizeof(unsigned int) * CHAR_BIT)
+
typedef struct _virDomainCapsStringValues virDomainCapsStringValues;
typedef virDomainCapsStringValues *virDomainCapsStringValuesPtr;
struct _virDomainCapsStringValues {
@@ -43,6 +46,8 @@ struct _virDomainCapsStringValues {
size_t nvalues; /* number of strings */
};
+STATIC_ASSERT_ENUM(VIR_DOMAIN_LOADER_TYPE_LAST);
+STATIC_ASSERT_ENUM(VIR_TRISTATE_BOOL_LAST);
typedef struct _virDomainCapsLoader virDomainCapsLoader;
typedef virDomainCapsLoader *virDomainCapsLoaderPtr;
struct _virDomainCapsLoader {
@@ -53,6 +58,7 @@ struct _virDomainCapsLoader {
virDomainCapsEnum secure; /* Info about secure:virTristateBool */
};
+STATIC_ASSERT_ENUM(VIR_DOMAIN_OS_DEF_FIRMWARE_LAST);
typedef struct _virDomainCapsOS virDomainCapsOS;
typedef virDomainCapsOS *virDomainCapsOSPtr;
struct _virDomainCapsOS {
@@ -61,6 +67,9 @@ struct _virDomainCapsOS {
virDomainCapsLoader loader; /* Info about virDomainLoaderDef */
};
+STATIC_ASSERT_ENUM(VIR_DOMAIN_DISK_DEVICE_LAST);
+STATIC_ASSERT_ENUM(VIR_DOMAIN_DISK_BUS_LAST);
+STATIC_ASSERT_ENUM(VIR_DOMAIN_DISK_MODEL_LAST);
typedef struct _virDomainCapsDeviceDisk virDomainCapsDeviceDisk;
typedef virDomainCapsDeviceDisk *virDomainCapsDeviceDiskPtr;
struct _virDomainCapsDeviceDisk {
@@ -71,6 +80,7 @@ struct _virDomainCapsDeviceDisk {
/* add new fields here */
};
+STATIC_ASSERT_ENUM(VIR_DOMAIN_GRAPHICS_TYPE_LAST);
typedef struct _virDomainCapsDeviceGraphics virDomainCapsDeviceGraphics;
typedef virDomainCapsDeviceGraphics *virDomainCapsDeviceGraphicsPtr;
struct _virDomainCapsDeviceGraphics {
@@ -78,6 +88,7 @@ struct _virDomainCapsDeviceGraphics {
virDomainCapsEnum type; /* virDomainGraphicsType */
};
+STATIC_ASSERT_ENUM(VIR_DOMAIN_VIDEO_TYPE_LAST);
typedef struct _virDomainCapsDeviceVideo virDomainCapsDeviceVideo;
typedef virDomainCapsDeviceVideo *virDomainCapsDeviceVideoPtr;
struct _virDomainCapsDeviceVideo {
@@ -85,6 +96,11 @@ struct _virDomainCapsDeviceVideo {
virDomainCapsEnum modelType; /* virDomainVideoType */
};
+STATIC_ASSERT_ENUM(VIR_DOMAIN_HOSTDEV_MODE_LAST);
+STATIC_ASSERT_ENUM(VIR_DOMAIN_STARTUP_POLICY_LAST);
+STATIC_ASSERT_ENUM(VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_LAST);
+STATIC_ASSERT_ENUM(VIR_DOMAIN_HOSTDEV_CAPS_TYPE_LAST);
+STATIC_ASSERT_ENUM(VIR_DOMAIN_HOSTDEV_PCI_BACKEND_TYPE_LAST);
typedef struct _virDomainCapsDeviceHostdev virDomainCapsDeviceHostdev;
typedef virDomainCapsDeviceHostdev *virDomainCapsDeviceHostdevPtr;
struct _virDomainCapsDeviceHostdev {
@@ -97,6 +113,8 @@ struct _virDomainCapsDeviceHostdev {
/* add new fields here */
};
+STATIC_ASSERT_ENUM(VIR_DOMAIN_RNG_MODEL_LAST);
+STATIC_ASSERT_ENUM(VIR_DOMAIN_RNG_BACKEND_LAST);
typedef struct _virDomainCapsDeviceRNG virDomainCapsDeviceRNG;
typedef virDomainCapsDeviceRNG *virDomainCapsDeviceRNGPtr;
struct _virDomainCapsDeviceRNG {
@@ -105,6 +123,7 @@ struct _virDomainCapsDeviceRNG {
virDomainCapsEnum backendModel; /* virDomainRNGBackend */
};
+STATIC_ASSERT_ENUM(VIR_GIC_VERSION_LAST);
typedef struct _virDomainCapsFeatureGIC virDomainCapsFeatureGIC;
typedef virDomainCapsFeatureGIC *virDomainCapsFeatureGICPtr;
struct _virDomainCapsFeatureGIC {
--
2.26.2