cfg_subsys_defaults(3)cfg_subsys_defaults(3)NAMEcfg_subsys_defaults - determine the /etc/sysconfigtab value for
selected attributes of a subsystem
SYNOPSIS
#include <cfg.h>
cfg_status_t cfg_subsys_defaults(
cfg_handle_t *handle,
caddr_t subsys,
cfg_attr_t *attributes,
int nattributes );
LIBRARY
Configuration Management Library (libcfg.a)
PARAMETERS
Structure identifying the means of communication between your applica‐
tion and the configuration manager server. For local requests, pass
NULL in this parameter. For remote requests, pass the value returned
from the cfg_connect() routine. Specifies the name of the subsystem
for which you are requesting default attribute values. On input, names
the attributes for which you are requesting a default value.
On return, contains information about the named attributes. The
information includes the attribute-specific status of the
cfg_subsys_defaults() request and the default value of the
attribute as specified in the /etc/sysconfigtab database. Spec‐
ifies the number of attributes in the input attribute list.
DESCRIPTION
Use the cfg_subsys_defaults() routine to get information about the
value assigned to attributes in the /etc/sysconfigtab database. You can
request information about one or more attributes, but you can get
information about only one subsystem at a time. (For information about
the /etc/sysconfigtab database, see sysconfigtab(4).)
In the call to the cfg_subsys_defaults() routine, your application
passes the subsystem name and a list of one or more attribute names.
The system reads this information and finds and collects the informa‐
tion about the named attributes. The system then returns the attribute
information to your application.
The information returned from the cfg_subsys_defaults() routine is
passed in a structure of type cfg_attr_t. If your application requests
information about more than one attribute, an array of structures is
returned. For information about this structure, see libcfg(3).
The following list describes the information returned to your applica‐
tion when it calls the cfg_subsys_defaults() routine: Attributes can be
integer, string, or binary data. However, the system is unable to
determine the data type of attributes by reading the /etc/sysconfigtab
database. Therefore, this field returns the CFG_ATTR_STRTYPE data type
for all attributes. The definition of each attribute in the subsystem
attribute table determines what operations you can perform on the
attribute. The system is unable to determine this information from the
/etc/sysconfigtab database, so this field is NULL on return from
cfg_subsys_defaults() requests. During a cfg_subsys_defaults()
request, the system assigns each attribute a status. The following ta‐
ble describes the status values your application might receive on
return from this routine:
─────────────────────────────────────────────────────────────────────
Status Code Meaning
─────────────────────────────────────────────────────────────────────
CFG_ATTR_SUCCESS Successful operation
CFG_ATTR_EEXISTS No attribute by that name exists
CFG_ATTR_EOP Attribute does not support the query operation
CFG_ATTR_ESUBSYS Subsystem failure (code within the subsystem
returned an error)
CFG_ATTR_EINDEX The index for an indexed attribute is out of
range
CFG_ATTR_EMEM Unable to allocate memory to return the attribute
value
─────────────────────────────────────────────────────────────────────
The value of each attribute is returned in a structure, which
contains a string representing the value of the attribute as it
is defined in the /etc/sysconfigtab database. If an attribute is
omitted from the database, the cfg_subsys_defaults() routine
returns a NULL attribute value.
The cfg_subsys_defaults() routine returns NULL for other fields
in the attribute value structure.
RETURN VALUES
Upon successful completion, cfg_subsys_defaults() returns CFG_SUCCESS.
Other return values indicate that an error has occurred. For informa‐
tion about handling return values from routines in the configuration
management library, see libcfg(3).
EXAMPLES
The following example illustrates the use of the cfg_subsys_defaults()
routine:
cfg_attr_t attributes[2]; cfg_status_t retval;
cfg_handle_t handle; int i;
/*****************************************************/ /* Initialize
attribute names for the request */
strcpy (attributes[0].name, "bufcache"); strcpy (attributes[1].name,
"max-vnodes");
/***************************************************/ /* Call the
cfg_subsys_defaults routine */
retval = cfg_subsys_defaults(&handle, "vfs", attributes, 2);
if (retval != CFG_SUCCESS)
print_error (retval);
else {
/* Use data returned from the request */
for (i=0; i<2; i++) {
printf ("%s", attributes[i].name);
if (attributes[i].status != CFG_ATTR_SUCCESS) {
switch (attributes[i].status){
case CFG_ATTR_EEXISTS:
printf("unknown attribute\n");
break;
case CFG_ATTR_EOP:
printf("attribute does not allow this operation\n");
break;
.
.
.
default:
printf("unknown error\n");
break;
}
continue;
}
/* Display attribute value to application user */
printf ("%s\n", attributes[i].attr.str.val);
}
free(attributes[i].attr.str.val);
break; }
In this example, the application requests information about two
attributes, bufcache and max-vnodes. When the cfg_subsys_defaults()
routine returns information about those attributes, the application
tests the return status of the routine and reports any errors returned.
If the cfg_subsys_defaults() routine returns CFG_SUCCESS, the status
for each attribute is tested and any errors are reported. The applica‐
tion displays the default value of attributes that return CFG_ATTR_SUC‐
CESS.
SEE ALSO
Commands: cfgmgr(8), sysconfig(8)
Routines: cfg_connect(3), cfg_subsys_defaults_all(3), libcfg(3)
Files: sysconfigtab(4)cfg_subsys_defaults(3)
