cfg_subsys_query_all(3)cfg_subsys_query_all(3)NAMEcfg_subsys_query_all - determine the value of all attributes for a sub‐
system
SYNOPSIS
#include <cfg.h>
cfg_status_t cfg_subsys_query_all(
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 management 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 getting attribute values. Returns information about
all attributes for the named subsystem. The information includes the
data type of the attribute, the list of operations supported by that
attribute, the attribute-specific status of the query operation, the
minimum and maximum allowed values for the attribute, and the current
value of the attribute. For binary data items, the information includes
the size of the attribute's current value. The system allocates memory
for this array, which you should free when the information in the array
is no longer needed, as shown in the EXAMPLES section. An integer
value specifying the number of attributes for which information has
been returned.
DESCRIPTION
Use the cfg_subsys_query_all() routine to get information about all the
attributes for a particular subsystem.
When your application calls the cfg_subsys_query_all() routine, it
passes the name of the subsystem for which you want information. The
system reads the subsystem name and finds and collects the information
about its attributes. The system then returns that information to your
application.
For array-type attributes, each individual array element will be
returned in a separate cfg_attr_t structure and the index field will
have the index value of the array element.
The information returned from the cfg_subsys_query_all() routine is
passed in a structure of type cfg_attr_t. If the subsystem has more
than one attribute, an array of structures is returned. For informa‐
tion about this structure, see libcfg(3).
The following list describes the information returned to your applica‐
tion when it calls the cfg_subsys_query_all() routine: Attributes can
be integer, string, or binary data. As defined in <sys/sysconfig.h>,
the integer data types can be CFG_ATTR_INTTYPE (int), CFG_ATTR_UINTTYPE
(uint), CFG_ATTR_LONGTYPE (long), or CFG_ATTR_ULONGTYPE (ulong). The
string data type is a character string type named CFG_ATTR_STRTYPE and
the binary data type is CFG_ATTR_BINTYPE. The definition of each
attribute in the subsystem code determines what operations you can per‐
form on the attribute. The possible operation codes are CFG_OP_QUERY
(you can request information about the attribute), CFG_OP_CONFIGURE
(you can set the attribute value when the subsystem is initially con‐
figured), and CFG_OP_RECONFIGURE (you can modify the value of the
attribute). During a query request, each attribute is assigned a sta‐
tus. The following table describes the status values your application
might receive from the cfg_subsys_query_all() 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. In addi‐
tion to the attribute value, this structure returns the minimum
and maximum value for the attribute and the disposal routine, if
any, to be called once the attribute value is returned. For
binary attributes, the length of attribute's current value is
also returned. (The disposal routine is used to free kernel mem‐
ory occupied by string and binary data.)
RETURN VALUES
Upon successful completion, cfg_subsys_query_all() 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_query_all()
library routine:
cfg_attr_t *attributes; cfg_status_t retval;
cfg_handle_t handle; int nattributes;
int i;
/***************************************************/ /* Call the
cfg_subsys_query_all routine */
retval = cfg_subsys_query_all(&handle, "vfs", &attributes, &nat‐
tributes);
if (retval != CFG_SUCCESS)
print_error (retval);
else {
/* Use data returned from the query */
for (i=0; i<nattributes; i++) {
printf ("%s", attributes[i].name);
if (attributes[i].status != CFG_ATTR_SUCCESS) {
switch (attributes[i].status){
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 */
switch (attributes[i].type){
case CFG_ATTR_INTTYPE:
printf ("%d\n", (int) attributes[i].attr.num.val);
break;
.
.
.
case CFG_ATTR_STRTYPE:
printf ("%s\n", (int) attributes[i].attr.str.val);
free(attributes[i].attr.str.val);
break;
case CFG_ATTR_BINTYPE:
printf ("%d bytes of binary data received\n", (int) \
attributes[i].attr.bin.val_size);
free(attributes[i].attr.str.val);
break;
}
}
/* Free the memory allocated by the configuration management */
/* library */
free(attributes); }
In this example, the application requests information about all
attributes of the vfs subsystem. When the cfg_subsys_query_all() rou‐
tine returns information about those attributes, the application tests
the return status of the routine. The application reports any errors
returned. If cfg_subsys_query_all() returns CFG_SUCCESS, the status for
each attribute is tested and any errors are reported. The application
displays the value of attributes that return CFG_ATTR_SUCCESS.
SEE ALSO
Commands: cfgmgr(8), sysconfig(8)
Routines: cfg_subsys_query(3), libcfg(3)cfg_subsys_query_all(3)