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cfg_psm_catops(3)
Contents
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cfg_psm_catops, cfg_psm_catadd, cfg_psm_catrem,
cfg_psm_catget - Perform category operations on the Process
Set Manager (PSM) set
Library: configuration management library, libcfg.a.
#include <cfg.h>
cfg_status_t cfg_psm_catadd(
const char *node,
const char *catnam ); cfg_status_t cfg_psm_catrem(
const char *node,
const char *catnam ); cfg_status_t cfg_psm_catget(
const char *node,
const char *catnam,
psm_catrsp_t **catrsp ); void cfg_psm_catfree(
psm_catrsp_t **catrsp );
Refer to PSM(4) for a description of the Process Set Manager,
which supports the functions described in this reference
page.
Functions [Toc] [Back]
Use these functions as follows: Adds the category defined
by the variable catnam to the process set on the host
defined by the value of host node. Removes the category
defined by the variable catnam from the process set on the
host defined by the value of host node. Retrieves the
category information from the process set on host node.
Information on all categories is returned if the value of
catnam is _PSM_ALLCAT, otherwise the data returned is limited
to category catnam. When the response is complete,
you must free memory using cfg_psm_catfree(). Frees the
memory allocated to the cfg_psm_catget() function.
Operation and Usage Instructions [Toc] [Back]
Upon successful completion of the cfg_psm_catget() function,
the catrsp parameter points to an array of one or
more struct psm_catrsp_s elements. These elements are
declared in the psm.h header file and are duplicated
below. Each element represents a specific category.
In case of an error, the catrsp parameter is set to NULL:
typedef struct psm_catrsp_s {
unsigned int crs_listidx; /* category number in
list */
unsigned int crs_listcnt; /* total categories in
list */
unsigned int crs_total; /* total matching categories
*/
unsigned int crs_memcnt; /* number of members */
char crs_cat[PSM_CATLEN]; /* category name */
} psm_catrsp_t;
These elements are defined as follows: crs_listidx holds
the index (starting at 1) of a category entry in the
array. crs_listcnt and crs_total hold the total number of
categories. Both values will always be the same when you
use the cfg_psm_catget() function. crs_memcnt contains
the number of process instances in the category, where
each instance represents a process. Processes included in
this count might be terminated. Refer to cfg_psm_memops(3)
for more information. crs_cat is the NULL-terminated category
name. In the case of a generic query and no instantiated
categories, an array of one element is returned
with all fields set to 0.
A catnam name string must not be longer than the number of
bytes specified by the value of PSM_CATLEN, including the
trailing NULL. The underlying KSM only supports a flat
namespace. To avoid potential problems between category
names, developers must use a common string followed by an
underscore preceding every name. For example, CPQ_kewld,
where CPQ_ is the string common to all names. Systemdefined
categories never contain an underscore.
There are no other restrictions on the value of catnam.
A list of some system-defined categories which are instantiated
at boot time is available from the external array
const char *_psm_categories[]. You can determine the number
of strings in this array by using const int _psm_ncategories.
Additionally, you can use the _PSM_CAT_*
indexes to locate specific category names in const char
*_psm_categories[]. These category names are most commonly
used by processes that self-register their instance(s).
See the cfg.h header file and cfg_psm_memops(3).
See PSM(4) for more information on the Process Set Manager.
The value of node is specified as _PSM_MYNODE when operating
on the process set of the local host, otherwise it
contains the name of a target host. Future implementations
will permit _PSM_ALLNODE to gather cluster-wide information,
or a comma-separated list of host names. A successful
response from any node guarantees a CFG_SUCCESS return
to the caller (errors from the other nodes are ignored).
In the present implementation, multinode queries return a
ENOTSUP subsystem error.
Upon successful completion, the cfg_psm_catadd(),
cfg_psm_catrem(), and cfg_psm_catget() functions return
CFG_SUCCESS. Other return values indicate that an error
has occurred. For information about handling return values
from routines in the configuration management library,
refer to libcfg(3).
The following subsystem errors might be merged with a
CFG_FRAME_SUCCESS response: An existing category of this
name was found when performing an add operation. There
was a general KSM failure during an add operation. The
PSM process set is not registered with KSM. The category
was not found during a remove or get operation. User or
kernel memory allocation failed. The maximum number of
categories is exceeded during an add operation. This
operation is not yet implemented.
The following example adds the abcd category to the local
host.
#include <cfg.h>
#include <stdio.h>
cfg_status_t retval;
if ((retval = cfg_psm_catadd(_PSM_MYNODE,
"abcd")) != CFG_SUCCESS) print_error(retval);
The following example retrieves all categories and
prints the names of those with four or more process
instances:
#include <cfg.h>
#include <stdio.h>
struct psm_catrsp_s *catrsp, *csp, *csp_e;
cfg_status_t retval;
retval = cfg_psm_catget(_PSM_MYNODE,
_PSM_ALLCAT, &catrsp;);
if (retval != CFG_SUCCESS) {
print_error(retval);
} else { csp = catrsp; csp_e =
catrsp + csp->crs_listcnt; while (csp <
csp_e) { if (csp->crs_memcnt >= 4)
puts(csp->crs_cat); csp++;
} cfg_psm_catfree(catrsp);
}
Functions: fork(2), libcfg(3), cfg_psm_memops(3) wait(2)
Files: PSM(4)
cfg_psm_catops(3)
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