1 files changed, 98 insertions, 0 deletions
diff --git a/agent/mibgroup/examples/watched.c b/agent/mibgroup/examples/watched.c
new file mode 100644
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+++ b/agent/mibgroup/examples/watched.c
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+/*
+ * watched.c
+ * $Id$
+ *
+ */
+/**  @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;
+    static 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));
+
+    /*
+     * 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 three options for a string watcher are:
+     *   fixed size string (length never changes)
+     *   variable size (length can be 0 - MAX, for some MAX)
+     *   c string (length can be 0 - MAX-1 for some max, \0 is not a valid
+     *     character in the string, the length is provided by strlen)
+     *
+     * we'll use a variable length string.
+     */
+    watcher_flags = WATCHER_MAX_SIZE;
+
+    /*
+     * create the watcher info for our string.
+     */
+    netsnmp_init_watcher_info6(&watcher_info, my_string, strlen(my_string),
+			       ASN_OCTET_STR, watcher_flags,
+			       sizeof(my_string), NULL);
+
+    /*
+     * the line below registers our "my_string" variable above as
+     * accessible and makes it writable. 
+     */
+    netsnmp_register_watched_instance(reginfo, &watcher_info);
+
+    DEBUGMSGTL(("example_string_instance",
+                "Done initalizing example string instance\n"));
+}