destruct and clone

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I have attached a first version of destruct and clone for
netsnmp_mib_handlers in order to demonstrate the concept.

I would really like to get comments on it.

The patch do incidentally fix a memory leak in the agent, and there are
more similar low hanging fruit available.

/MF

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Index: include/net-snmp/agent/agent_handler.h
================================================== =================
--- include/net-snmp/agent/agent_handler.h (revision 16840)
+++ include/net-snmp/agent/agent_handler.h (working copy)
@@ -64,6 +64,15 @@ typedef struct netsnmp_mib_handler_s {

struct netsnmp_mib_handler_s *next;
struct netsnmp_mib_handler_s *prev;
+
+ /** delete the myvoid member - default is to do nothing */
+ void (*delete_method)(void *);
+
+ /** deep copy the myvoid member - default is to copy the pointer
+ * returns 0 on success, -1 on failure
+ */
+ int (*clone_method)(void **dest, void *src);
+
} netsnmp_mib_handler;

/*
Index: agent/helpers/scalar_group.c
================================================== =================
--- agent/helpers/scalar_group.c (revision 16840)
+++ agent/helpers/scalar_group.c (working copy)
@@ -16,6 +16,22 @@
#include <net-snmp/agent/serialize.h>
#include <net-snmp/agent/read_only.h>

+static int
+clone_scalar_group(netsnmp_scalar_group** dest, netsnmp_scalar_group* src)
+{
+ if (src) {
+ netsnmp_scalar_group *t = SNMP_MALLOC_TYPEDEF(netsnmp_scalar_group);
+ if(t != NULL) {
+ t->lbound = src->lbound;
+ t->ubound = src->ubound;
+ *dest = t;
+ return 0;
+ } else
+ return -1;
+ } else
+ return 0;
+}
+
/** @defgroup scalar_group_group scalar_group
* Process groups of scalars.
* @ingroup leaf
@@ -39,6 +55,8 @@ netsnmp_get_scalar_group_handler(oid fir
sgroup->lbound = first;
sgroup->ubound = last;
ret->myvoid = (void *)sgroup;
+ ret->delete_method = free;
+ ret->clone_method = clone_scalar_group;
}
}
return ret;
Index: agent/agent_handler.c
================================================== =================
--- agent/agent_handler.c (revision 16840)
+++ agent/agent_handler.c (working copy)
@@ -579,6 +579,10 @@ netsnmp_handler_free(netsnmp_mib_handler
* defined. About 30 functions down the stack, starting
* in clear_context() -> clear_subtree()
*/
+ if(handler->delete_method) {
+ handler->delete_method(handler->myvoid);
+ handler->myvoid = NULL;
+ }
SNMP_FREE(handler->handler_name);
SNMP_FREE(handler);
}
@@ -599,7 +603,13 @@ netsnmp_handler_dup(netsnmp_mib_handler
h = _clone_handler(handler);

if (h != NULL) {
- h->myvoid = handler->myvoid;
+ if (handler->clone_method) {
+ if(handler->clone_method(&h->myvoid, handler->myvoid) != 0) {
+ netsnmp_handler_free(h);
+ return NULL;
+ }
+ } else
+ h->myvoid = handler->myvoid;

if (handler->next != NULL) {
h->next = netsnmp_handler_dup(handler->next);
@@ -873,8 +883,11 @@ _clone_handler(netsnmp_mib_handler *it)
return NULL;

dup = netsnmp_create_handler(it->handler_name, it->access_method);
- if(NULL != dup)
+ if(NULL != dup) {
dup->flags = it->flags;
+ dup->delete_method = it->delete_method;
+ dup->clone_method = it->clone_method;
+ }

return dup;
}

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