From 91f737383c7c4be70689c9d6ce809de00dc1485e Mon Sep 17 00:00:00 2001 From: Tony Asleson Date: Mon, 4 May 2015 14:51:41 -0500 Subject: lvm2app: Add signed numerical property values Currently lvm2app properties have the following structure: typedef struct lvm_property_value { uint32_t is_settable:1; uint32_t is_string:1; uint32_t is_integer:1; uint32_t is_valid:1; uint32_t padding:28; union { const char *string; uint64_t integer; } value; } lvm_property_value_t; which assumes that numerical values were in the range of 0 to 2**64-1. However, some of the properties were 'signed', like LV major/minor numbers and some reserved values for properties that represent percentages. Thus when the values were retrieved they were in two's complement notation. So for a -1 major number the API user would get a value of 18446744073709551615. The API user could cast the returned value to an int64_t to handle this, but that requires the API developer to look at the source code and determine when it should be done. This change modifies the return property structure to: typedef struct lvm_property_value { uint32_t is_settable:1; uint32_t is_string:1; uint32_t is_integer:1; uint32_t is_valid:1; uint32_t is_signed:1; uint32_t padding:27; union { const char *string; uint64_t integer; int64_t signed_integer; } value; } lvm_property_value_t; With this addition the API user can interrogate that the value is numerical, (is_integer = 1) and subsequently check if it's signed (is_signed = 1) too. If signed, then the API developer should use the union's signed_integer to avoid casting. This change maintains backwards compatibility as the structure size remains unchanged and integer value remains unchanged. Only the additional bit taken from the pad is utilized. Bugzilla reference: https://bugzilla.redhat.com/show_bug.cgi?id=838257 Signed-off-by: Tony Asleson --- liblvm/lvm_misc.c | 1 + 1 file changed, 1 insertion(+) (limited to 'liblvm/lvm_misc.c') diff --git a/liblvm/lvm_misc.c b/liblvm/lvm_misc.c index ff26cdfb2..431d35426 100644 --- a/liblvm/lvm_misc.c +++ b/liblvm/lvm_misc.c @@ -88,6 +88,7 @@ struct lvm_property_value get_property(const pv_t pv, const vg_t vg, v.is_settable = prop.is_settable; v.is_string = prop.is_string; v.is_integer = prop.is_integer; + v.is_signed = prop.is_signed; if (v.is_string) v.value.string = prop.value.string; if (v.is_integer) -- cgit v1.2.1