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lvm2/liblvm/lvm_misc.c
Tony Asleson 91f737383c 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 <tasleson@redhat.com>
2015-05-06 08:51:04 -05:00

169 lines
3.8 KiB
C

/*
* Copyright (C) 2008-2013 Red Hat, Inc. All rights reserved.
*
* This file is part of LVM2.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU Lesser General Public License v.2.1.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "lib.h"
#include "properties.h"
#include "lvm_misc.h"
#include "lvm2app.h"
#include "lvm_prop.h"
struct dm_list *tag_list_copy(struct dm_pool *p, struct dm_list *tag_list)
{
struct dm_list *list;
lvm_str_list_t *lsl;
struct dm_str_list *sl;
if (!(list = dm_pool_zalloc(p, sizeof(*list)))) {
log_errno(ENOMEM, "Memory allocation fail for dm_list.");
return NULL;
}
dm_list_init(list);
dm_list_iterate_items(sl, tag_list) {
if (!(lsl = dm_pool_zalloc(p, sizeof(*lsl)))) {
log_errno(ENOMEM,
"Memory allocation fail for lvm_lv_list.");
return NULL;
}
if (!(lsl->str = dm_pool_strdup(p, sl->str))) {
log_errno(ENOMEM,
"Memory allocation fail for lvm_lv_list->str.");
return NULL;
}
dm_list_add(list, &lsl->list);
}
return list;
}
struct lvm_property_value get_property(const pv_t pv, const vg_t vg,
const lv_t lv,
const lvseg_t lvseg,
const pvseg_t pvseg,
const struct lvcreate_params *lvcp,
const struct pvcreate_params *pvcp,
const char *name)
{
struct lvm_property_type prop;
struct lvm_property_value v = { 0 };
prop.id = name;
if (pv) {
if (!pv_get_property(pv, &prop))
return v;
} else if (vg) {
if (!vg_get_property(vg, &prop))
return v;
} else if (lv) {
if (!lv_get_property(lv, &prop))
return v;
} else if (lvseg) {
if (!lvseg_get_property(lvseg, &prop))
return v;
} else if (pvseg) {
if (!pvseg_get_property(pvseg, &prop))
return v;
} else if (lvcp) {
if (!lv_create_param_get_property(lvcp, &prop))
return v;
} else if (pvcp) {
if (!pv_create_param_get_property(pvcp, &prop))
return v;
} else {
log_errno(EINVAL, "Invalid NULL handle passed to library function.");
return v;
}
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)
v.value.integer = prop.value.integer;
v.is_valid = 1;
return v;
}
int set_property(const pv_t pv, const vg_t vg, const lv_t lv,
struct lvcreate_params *lvcp,
struct pvcreate_params *pvcp,
const char *name,
struct lvm_property_value *v)
{
struct lvm_property_type prop;
prop.id = name;
if (v->is_string)
prop.value.string = v->value.string;
else
prop.value.integer = v->value.integer;
if (pv) {
if (!pv_set_property(pv, &prop)) {
v->is_valid = 0;
return -1;
}
} else if (vg) {
if (!vg_set_property(vg, &prop)) {
v->is_valid = 0;
return -1;
}
} else if (lv) {
if (!lv_set_property(lv, &prop)) {
v->is_valid = 0;
return -1;
}
} else if (lvcp) {
if (!lv_create_param_set_property(lvcp, &prop)) {
v->is_valid = 0;
return -1;
}
} else if (pvcp) {
if (!pv_create_param_set_property(pvcp, &prop)) {
v->is_valid = 0;
return -1;
}
} else {
return -1;
}
return 0;
}
/*
* Store anything that may need to be restored back to the user on library
* call exit. Currently the only thing we are preserving is the users umask.
*/
struct saved_env store_user_env(struct cmd_context *cmd)
{
struct saved_env env = {0};
if (cmd) {
env.user_umask = umask(cmd->default_settings.umask);
} else {
env.user_umask = umask(0);
umask(env.user_umask);
}
return env;
}
void restore_user_env(const struct saved_env *env)
{
if (env) {
umask(env->user_umask);
}
}