请教个问题.scalar_int.c 获取值的问题.

unix_pro

小弟纯粹新手,各位多多指教.

我想让 test这个函数能够 得到 example1这个值.

example1这个值不是 已经定义好的,而是 snmp set过的值.

http://linux.die.net/man/3/netsnmp_instance 这里有    netsnmp_register_int_instance 定义.

1. /**  @example scalar_int.c
   
2. *  This example creates some scalar registrations that allows
   
3. *  some simple variables to be accessed via SNMP.  In a more
   
4. *  realistic example, it is likely that these variables would also be
   
5. *  manipulated in other ways outside of SNMP gets/sets.
   
6. *
   
7. *  If this module is compiled into an agent, you should be able to
   
8. *  issue snmp commands that look something like (authentication
   
9. *  information not shown in these commands):
   
10. *
    
11. *  - snmpget localhost netSnmpExampleInteger.0
    
12. *  - netSnmpExampleScalars = 42
    
13. *
    
14. *  - snmpset localhost netSnmpExampleInteger.0 = 1234
    
15. *  - netSnmpExampleScalars = 1234
    
16. *  
    
17. *  - snmpget localhost netSnmpExampleInteger.0
    
18. *  - netSnmpExampleScalars = 1234
    
19. *
    
20. */
    
21. 
    
22. /*
    
23. * start be including the appropriate header files
    
24. */
    
25. 
    
26. #include <net-snmp/net-snmp-config.h>
    
27. #include <net-snmp/net-snmp-includes.h>
    
28. #include <net-snmp/agent/net-snmp-agent-includes.h>
    
29. 
    
30. /*
    
31. * Then, we declare the variables we want to be accessed
    
32. */
    
33. static int      example1 = 42;  /* default value */
    
34. //int test(int);
    
35. void  test (int);
    
36. /*
    
37. * our initialization routine, automatically called by the agent
    
38. * (to get called, the function name must match init_FILENAME())
    
39. */
    
40. void
    
41. init_scalar_int(void)
    
42. {
    
43.     /*
    
44.      * the OID we want to register our integer at.  This should be a
    
45.      * fully qualified instance.  In our case, it's a scalar at:
    
46.      * NET-SNMP-EXAMPLES-MIB::netSnmpExampleInteger.0 (note the
    
47.      * trailing 0 which is required for any instantiation of any
    
48.      * scalar object)
    
49.      */
    
50.     oid             my_registration_oid[] =
    
51.         { 1, 3, 6, 1, 4, 1, 17711, 2, 1, 1, 0 };
    
52. 
    
53.     /*
    
54.      * a debugging statement.  Run the agent with -Dexample_scalar_int to see
    
55.      * the output of this debugging statement.
    
56.      */
    
57.     DEBUGMSGTL(("example_scalar_int",
    
58.                 "Initalizing example scalar int.  Default value = %d\n",
    
59.                 example1));
    
60. 
    
61.     /*
    
62.      * the line below registers our "example1" variable above as
    
63.      * accessible and makes it writable.  A read only version of the
    
64.      * same registration would merely call
    
65.      * register_read_only_int_instance() instead.
    
66.      *
    
67.      * If we wanted a callback when the value was retrieved or set
    
68.      * (even though the details of doing this are handled for you),
    
69.      * you could change the NULL pointer below to a valid handler
    
70.      * function.
    
71.      */
    
72.     netsnmp_register_int_instance("my example int variable",
    
73.                                   my_registration_oid,
    
74.                                   OID_LENGTH(my_registration_oid),
    
75.                                   &example1, test(example1)); //调用其他执行函数
    
76. 
    
77.     DEBUGMSGTL(("example_scalar_int",
    
78.                 "Done initalizing example scalar int\n"));
    
79. 
    
80. 
    
81. }
    
82. 
    
83. 
    
84. void test (int example1){
    
85.         static char tmp[50];
    
86.         sprintf(tmp,"iwconfig ath1 essid eth%d",&example1);
    
87.         system(tmp);
    
88. }
    
89. 
    
90. /*
    
91. int test        (void){
    
92.         static char                                tmp[50];
    
93.         int                  essidvar = &example1;
    
94.         sprintf(tmp,"iwconfig ath1 essid eth%d",essidvar);
    
95.         system(tmp);
    
96. }
    
97. */
    
98. //int test (void)
    
99. //{
    
100. //        system("echo b > /var/sys.conf");
     
101.         //return EXIT_SUCCESS;
     
102. //}
     

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unix_pro

1. int
   
2. netsnmp_register_int_instance(const char *name,
   
3.                               oid * reg_oid, size_t reg_oid_len,
   
4.                               int *it, Netsnmp_Node_Handler * subhandler)
   
5. {
   
6.     netsnmp_handler_registration *myreg;
   
7. 
   
8.     myreg = get_reg(name, "int_handler", reg_oid, reg_oid_len, it,
   
9.                     HANDLER_CAN_RWRITE, netsnmp_instance_int_handler,
   
10.                     subhandler, NULL);
    
11.     return netsnmp_register_instance(myreg);
    
12. }
    

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