[lvm-devel] [PATCH 5/8] Add lvm_vg_get_property() generic vg property function.
Dave Wysochanski
dwysocha at redhat.com
Tue Oct 19 11:32:52 UTC 2010
Add a generic VG property function to lvm2app. Call the internal library
vg_get_property() function. Strings are dup'd internally.
Rework lvm_vg_get_property to return lvm_property_value and require caller
to check 'is_valid' flag and lvm_errno() for API error.
Create a 'get_property' function, local to lvm2app, that factors out
most of the common code that copies the components of lvm_property_type
into lvm_property_value. This allows for a 1-line function for each
of the generic property functions exported by lvm2app.
Signed-off-by: Dave Wysochanski <dwysocha at redhat.com>
---
liblvm/lvm2app.h | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
liblvm/lvm_misc.c | 34 +++++++++++++++++++++++++++++
liblvm/lvm_misc.h | 2 +
liblvm/lvm_vg.c | 6 +++++
4 files changed, 103 insertions(+), 1 deletions(-)
diff --git a/liblvm/lvm2app.h b/liblvm/lvm2app.h
index 47d3417..8b244fc 100644
--- a/liblvm/lvm2app.h
+++ b/liblvm/lvm2app.h
@@ -139,7 +139,7 @@ typedef struct physical_volume *pv_t;
/**
* Logical Volume object list.
*
- * Lists of these structures are returned by lvm_vg_list_pvs().
+ * Lists of these structures are returned by lvm_vg_list_lvs().
*/
typedef struct lvm_lv_list {
struct dm_list list;
@@ -168,6 +168,27 @@ typedef struct lvm_str_list {
const char *str;
} lvm_str_list_t;
+/**
+ * Property Value
+ *
+ * This structure defines a single LVM property value for an LVM object.
+ * The structures are returned by functions such as
+ * lvm_vg_get_property() and lvm_vg_set_property().
+ *
+ * is_settable: indicates whether a 'set' function exists for this property
+ * is_string: indicates whether this property is a string (1) or integer (0)
+ * is_valid: indicates whether 'value' is valid (1) or not (0)
+ */
+typedef struct lvm_property_value {
+ unsigned is_settable:1;
+ unsigned is_string:1;
+ unsigned is_valid:1;
+ union {
+ const char *string;
+ uint64_t integer;
+ } value;
+} lvm_property_value_t;
+
/*************************** generic lvm handling ***************************/
/**
* Create a LVM handle.
@@ -848,6 +869,45 @@ uint64_t lvm_vg_get_max_lv(const vg_t vg);
*/
struct dm_list *lvm_vg_get_tags(const vg_t vg);
+/**
+ * Get the value of a VG property
+ *
+ * \memberof vg_t
+ *
+ * \param vg
+ * VG handle obtained from lvm_vg_create() or lvm_vg_open().
+ *
+ * \param name
+ * Name of property to query. See vgs 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 v;
+ * char *prop_name = "vg_mda_count";
+ *
+ * v = lvm_vg_get_property(vg, prop_name);
+ * if (lvm_errno(libh) || !v.is_valid) {
+ * // handle error
+ * printf("Invalid property name or unable to query"
+ * "'%s'.\n", prop_name);
+ * return;
+ * }
+ * if (v.is_string)
+ * printf(", value = %s\n", v.value.string);
+ * else
+ * printf(", value = %"PRIu64"\n", v.value.integer);
+ *
+ *
+ * \return
+ * lvm_property_value structure that will contain the current
+ * value of the property. Caller should check lvm_errno() as well
+ * as 'is_valid' flag before using the value.
+ */
+struct lvm_property_value lvm_vg_get_property(const vg_t vg, const char *name);
+
/************************** logical volume handling *************************/
/**
diff --git a/liblvm/lvm_misc.c b/liblvm/lvm_misc.c
index e339faa..52f3636 100644
--- a/liblvm/lvm_misc.c
+++ b/liblvm/lvm_misc.c
@@ -15,6 +15,7 @@
#include "lvm2app.h"
#include "lvm_misc.h"
#include "lib.h"
+#include "properties.h"
struct dm_list *tag_list_copy(struct dm_pool *p, struct dm_list *tag_list)
{
@@ -43,3 +44,36 @@ struct dm_list *tag_list_copy(struct dm_pool *p, struct dm_list *tag_list)
}
return list;
}
+
+struct lvm_property_value get_property(const pv_t pv, const vg_t vg,
+ const lv_t lv, const char *name)
+{
+ struct lvm_property_type prop;
+ struct lvm_property_value v;
+
+ prop.id = name;
+ if (pv) {
+ if (!pv_get_property(pv, &prop)) {
+ v.is_valid = 0;
+ return v;
+ }
+ } else if (vg) {
+ if (!vg_get_property(vg, &prop)) {
+ v.is_valid = 0;
+ return v;
+ }
+ } else if (lv) {
+ if (!lv_get_property(lv, &prop)) {
+ v.is_valid = 0;
+ return v;
+ }
+ }
+ v.is_settable = prop.is_settable;
+ v.is_string = prop.is_string;
+ if (v.is_string)
+ v.value.string = prop.value.string;
+ else
+ v.value.integer = prop.value.integer;
+ v.is_valid = 1;
+ return v;
+}
diff --git a/liblvm/lvm_misc.h b/liblvm/lvm_misc.h
index ced1f0f..b4e675e 100644
--- a/liblvm/lvm_misc.h
+++ b/liblvm/lvm_misc.h
@@ -17,5 +17,7 @@
#include "libdevmapper.h"
struct dm_list *tag_list_copy(struct dm_pool *p, struct dm_list *tag_list);
+struct lvm_property_value get_property(const pv_t pv, const vg_t vg,
+ const lv_t lv, const char *name);
#endif
diff --git a/liblvm/lvm_vg.c b/liblvm/lvm_vg.c
index a09208a..6970910 100644
--- a/liblvm/lvm_vg.c
+++ b/liblvm/lvm_vg.c
@@ -335,6 +335,12 @@ const char *lvm_vg_get_name(const vg_t vg)
return dm_pool_strndup(vg->vgmem, (const char *)vg->name, NAME_LEN+1);
}
+
+struct lvm_property_value lvm_vg_get_property(const vg_t vg, const char *name)
+{
+ return get_property(NULL, vg, NULL, name);
+}
+
struct dm_list *lvm_list_vg_names(lvm_t libh)
{
return get_vgnames((struct cmd_context *)libh, 0);
--
1.7.2.2
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