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/*
* watched.c
* $Id: watched.c 12097 2005-04-20 18:03:47Z rstory $
*
*/
/** @example watched.c
* These examples creates some scalar registrations that allows
* some simple variables to be accessed via SNMP. In a more
* realistic example, it is likely that these variables would also be
* manipulated in other ways outside of SNMP gets/sets.
*/
/*
* start by including the appropriate header files
*/
#include <net-snmp/net-snmp-config.h>
#include <net-snmp/net-snmp-includes.h>
#include <net-snmp/agent/net-snmp-agent-includes.h>
void init_watched_string(void);
void init_watched(void)
{
init_watched_string();
}
void init_watched_string(void)
{
/*
* the storage for our string. It must be static or allocated.
* we use static here for simplicity.
*/
static char my_string[256] = "So long, and thanks for all the fish!";
/*
* the OID we want to register our string at. This should be a
* fully qualified instance. In our case, it's a scalar at:
* NET-SNMP-EXAMPLES-MIB::netSnmpExampleString.0 (note the trailing
* 0 which is required for any instantiation of any scalar object)
*/
oid my_registration_oid[] =
{ 1, 3, 6, 1, 4, 1, 8072, 2, 1, 3, 0 };
/*
* variables needed for registration
*/
netsnmp_handler_registration *reginfo;
netsnmp_watcher_info *watcher_info;
int watcher_flags;
/*
* a debugging statement. Run the agent with -Dexample_string_instance
* to see the output of this debugging statement.
*/
DEBUGMSGTL(("example_string_instance",
"Initalizing example string instance. Default value = %s\n",
my_string));
/*
* create the registration info for our string. If you want to
*
* If we wanted a callback when the value was retrieved or set
* (even though the details of doing this are handled for you),
* you could change the NULL pointer below to a valid handler
* function.
*
* Change RWRITE to RONLY for a read-only string.
*/
reginfo = netsnmp_create_handler_registration("my example string", NULL,
my_registration_oid,
OID_LENGTH(my_registration_oid),
HANDLER_CAN_RWRITE);
/*
* the two options for a string watcher are:
* fixed size string (length never changes)
* variable size (length can be 0 - MAX, for some MAX)
*
* we'll use a variable length string.
*/
watcher_flags = WATCHER_MAX_SIZE;
/*
* create the watcher info for our string, and set the max size.
*/
watcher_info =
netsnmp_create_watcher_info(my_string, strlen(my_string),
ASN_OCTET_STR, watcher_flags);
watcher_info->max_size = sizeof(my_string);
/*
* the line below registers our "my_string" variable above as
* accessible and makes it writable.
*
* If we wanted a callback when the value was retrieved or set
* (even though the details of doing this are handled for you),
* you could change the NULL pointer below to a valid handler
* function.
*/
netsnmp_register_watched_instance(reginfo, watcher_info);
DEBUGMSGTL(("example_string_instance",
"Done initalizing example string instance\n"));
}
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