about modifying files generated by mib2c

i generated .c and .h of my test mib by mib2c and also can snmptraslate my
test mib tree under experimental nod as you can see
[littlepi@localhost project]# snmptranslate -IR -Tp jmtest
+--jmtest(72)
   +-- -RW- INTEGER   firstKey(1)
            Range: 0..100

and then i modified the files generated by mib2c and put it in mibgroup/ and
./configure --with-mib-modules="jmtest" , recompiled ,as a result ,generated
.o and .lo files of my test mib code in mibgroup/ .but when i tried this
command,i got the wrong value not correspond to my set in c code as you can
see in the following.and particularly, for restart snmpd each time ,i got
the different value although i didn't do anything else. so is there
something wrong with modifying i did to the files generated by mib2c??
i pasted my modified c code files and my test mib ASN.1 document.

[littlepi@localhost project]# snmpget -v 1 -c public localhost
jmtest.firstKey.0
JM-TEST-1-MIB::firstKey.0 = INTEGER: -1074568504

my test mib is as following:
JM-TEST-1-MIB DEFINITIONS ::= BEGIN

IMPORTS
        MODULE-IDENTITY,
        OBJECT-TYPE,
        INTEGER
                FROM SNMPv2-SMI;

jmtest MODULE-IDENTITY
    LAST-UPDATED "200203210000Z"
    ORGANIZATION "Temple U"
    CONTACT-INFO
        "None yet."
    DESCRIPTION
        "AgentX testing MIB"
    REVISION     "200203210000Z"
    DESCRIPTION
        "None yet."
    ::= { experimental 72}

firstKey OBJECT-TYPE
    SYNTAX      INTEGER (0..100)
    MAX-ACCESS  read-write
    STATUS      current
    DESCRIPTION
        "Value initialized to 0 and on each
         access:
         - Return current val.
         - increment"

    ::= { jmtest 1 }

END

jmtest.c I modified for test:



/*
 * Note: this file originally auto-generated by mib2c using
 *        : mib2c.old-api.conf,v 1.4 2004/07/28 08:04:58 dts12 Exp $
 */

#include <net-snmp/net-snmp-config.h>
#include <net-snmp/net-snmp-includes.h>
#include <net-snmp/agent/net-snmp-agent-includes.h>
#include "jmtest.h"

/*
 * jmtest_variables_oid:
 *   this is the top level oid that we want to register under.  This
 *   is essentially a prefix, with the suffix appearing in the
 *   variable below.
 */

oid             jmtest_variables_oid[] = { 1, 3, 6, 1, 3, 72 };

/*
 * variable4 jmtest_variables:
 *   this variable defines function callbacks and type return information
 *   for the  mib section
 */

struct variable4 jmtest_variables[] = {
    /*
     * magic number        , variable type , ro/rw , callback fn  , L,
oidsuffix
     */
#define FIRSTKEY  1
    {FIRSTKEY, ASN_INTEGER, RWRITE, var_jmtest, 1, {1}},

};

/*
 * (L = length of the oidsuffix)
 */


/** Initializes the jmtest module */
void
init_jmtest(void)
{

    DEBUGMSGTL(("jmtest", "Initializing\n"));

    /*
     * register ourselves with the agent to handle our mib tree
     */
    REGISTER_MIB("jmtest", jmtest_variables, variable4,
                 jmtest_variables_oid);

    /*
     * place any other initialization junk you need here
     */
}

/*
 * var_jmtest():
 *   This function is called every time the agent gets a request for
 *   a scalar variable that might be found within your mib section
 *   registered above.  It is up to you to do the right thing and
 *   return the correct value.
 *     You should also correct the value of "var_len" if necessary.
 *
 *   Please see the documentation for more information about writing
 *   module extensions, and check out the examples in the examples
 *   and mibII directories.
 */
unsigned char  *
var_jmtest(struct variable *vp,
           oid * name,
           size_t *length,
           int exact, size_t *var_len, WriteMethod ** write_method)
{
    /*
     * variables we may use later
     */
    static long     long_ret;
    static u_long   ulong_ret;
    static unsigned char string[SPRINT_MAX_LEN];
    static oid      objid[MAX_OID_LEN];
    static struct counter64 c64;
 int   VAR;

    if (header_generic(vp, name, length, exact, var_len, write_method)
        == MATCH_FAILED)
        return NULL;

    /*
     * this is where we do the value assignments for the mib results.
     */
    switch (vp->magic) {
    case FIRSTKEY:
        *write_method = write_firstKey;
        VAR = 1;            /* XXX */
  *var_len =sizeof(VAR);
        return (u_char *) & VAR;
    default:
        ERROR_MSG("");
    }
    return NULL;
}

int
write_firstKey(int action,
               u_char * var_val,
               u_char var_val_type,
               size_t var_val_len,
               u_char * statP, oid * name, size_t name_len)
{
    long            value;
    int             size;

    switch (action) {
    case RESERVE1:
        if (var_val_type != ASN_INTEGER) {
            fprintf(stderr, "write to jmtest not ASN_INTEGER\n");
            return SNMP_ERR_WRONGTYPE;
        }
        if (var_val_len > sizeof(long)) {
            fprintf(stderr, "write to jmtest: bad length\n");
            return SNMP_ERR_WRONGLENGTH;
        }
        break;

    case RESERVE2:
        size = var_val_len;
        value = *(long *) var_val;

        break;

    case FREE:
        /*
         * Release any resources that have been allocated
         */
        break;

    case ACTION:
        /*
         * The variable has been stored in 'value' for you to use,
         * and you have just been asked to do something with it.
         * Note that anything done here must be reversable in the UNDO case
         */
        break;

    case UNDO:
        /*
         * Back out any changes made in the ACTION case
         */
        break;

    case COMMIT:
        /*
         * Things are working well, so it's now safe to make the change
         * permanently.  Make sure that anything done here can't fail!
         */
        break;
    }
    return SNMP_ERR_NOERROR;
}







-- 
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