Add lvm_pv_get_property() generic function to obtain value of any pv property.

Add a generic PV property function to lvm2app, similar to VG function.
Return lvm_property_value and require caller to check 'is_valid' flag
before using the value.  If 'is_valid' is not set, then lvm_errno()
should be used to obtain the specific error.

liblvm/lvm2app.h

@@ -1242,6 +1242,44 @@ uint64_t lvm_pv_get_size(const pv_t pv);
  */
 uint64_t lvm_pv_get_free(const pv_t pv);
 
+/**
+ * Get the value of a PV property
+ *
+ * \memberof pv_t
+ *
+ * \param   pv
+ * Physical volume handle.
+ *
+ * \param   name
+ * Name of property to query.  See pvs man page for full list of properties
+ * that may be queried.
+ *
+ * The memory allocated for a string property value is tied to the vg_t
+ * handle and will be released when lvm_vg_close() is called.
+ *
+ * Example:
+ *      lvm_property_value value;
+ *      char *prop_name = "pv_mda_count";
+ *
+ *      v = lvm_pv_get_property(pv, prop_name);
+ *      if (!v.is_valid) {
+ *           printf("Invalid property name or unable to query"
+ *                  "'%s', errno = %d.\n", prop_name, lvm_errno(libh));
+ *           return;
+ *      }
+ *      if (v.is_string)
+ *           printf(", value = %s\n", v.value.string);
+ *	if (v.is_integer)
+ *           printf(", value = %"PRIu64"\n", v.value.integer);
+ *
+ * \return
+ * lvm_property_value structure that will contain the current
+ * value of the property.  Caller should check 'is_valid' flag before using
+ * the value.  If 'is_valid' is not set, caller should check lvm_errno()
+ * for specific error.
+ */
+struct lvm_property_value lvm_pv_get_property(const pv_t pv, const char *name);
+
 /**
  * Resize physical volume to new_size bytes.
  *

liblvm/lvm_pv.c

@@ -16,6 +16,7 @@
 #include "lvm2app.h"
 #include "metadata.h"
 #include "lvm-string.h"
+#include "lvm_misc.h"
 
 const char *lvm_pv_get_uuid(const pv_t pv)
 {
@@ -48,6 +49,11 @@ uint64_t lvm_pv_get_free(const pv_t pv)
 	return (uint64_t) SECTOR_SIZE * pv_free(pv);
 }
 
+struct lvm_property_value lvm_pv_get_property(const pv_t pv, const char *name)
+{
+	return get_property(pv, NULL, NULL, name);
+}
+
 int lvm_pv_resize(const pv_t pv, uint64_t new_size)
 {
 	/* FIXME: add pv resize code here */