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cfg_subsys_defaults(3)
NAME
cfg_subsys_defaults - Determine the /etc/sysconfigtab value for selected
attributes of a subsystem
LIBRARY
Configuration Management Library (libcfg.a)
SYNOPSIS
#include <cfg.h>
cfg_status_t cfg_subsys_defaults(
cfg_handle_t *handle,
caddr_t subsys,
cfg_attr_t *attributes,
int nattributes);
PARAMETERS
handle Structure identifying the means of communication between your
application 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.
subsys Specifies the name of the subsystem for which you are requesting
default attribute values.
attributes
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.
nattributes
Specifies 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 information 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 application
when it calls the cfg_subsys_defaults() routine:
Attribute data type
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.
Attribute operations
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.
Attribute status
During a cfg_subsys_defaults() request, the system assigns each
attribute a status. The following table 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
_________________________________________________________________
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.
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 application displays
the default value of attributes that return CFG_ATTR_SUCCESS.
RETURN VALUES
Upon successful completion, cfg_subsys_defaults() returns CFG_SUCCESS.
Other return values indicate that an error has occurred. For information
about handling return values from routines in the configuration management
library, see libcfg(3).
RELATED INFORMATION
Commands: cfgmgr(8), sysconfig(8)
Routines: cfg_connect(3), cfg_subsys_defaults_all(3), libcfg(3)
Files: sysconfigtab(4)
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