Patch: Add init and cleanup functions to registry backends and call them if they are defined

[Richard Sharpe]

On Mon, Jan 12, 2015 at 1:45 PM, Jeremy Allison <jra at samba.org> wrote:
> On Sun, Jan 11, 2015 at 11:59:44AM -0800, Richard Sharpe wrote:
>> On Sat, Jan 10, 2015 at 1:02 PM, Richard Sharpe
>> <realrichardsharpe at gmail.com> wrote:
>> > Hi folks,
>> >
>> > Sometimes, as in my zookeeper backend, you need an init and cleanup function.
>> >
>> > This small patch provides that.
>> >
>> > Please provide feedback or push if OK ...
>>
>> A small update. If the init function fails, we should not install it.
>> Rather, we should print a level 0 message in the log.
>
> Can you call the functions registry_ops_init()/registry_ops_cleanup()
> not just init() and cleanup() please ?

Attached is a new patch that does as you ask.

> Also, rather than calling these inside the reghook_cache_add()
> function, shouldn't these be called inside reghook_cache_init() ?

No, since that function does very little and I need to replace the
hook functions in the latest work I am doing, so I need this does at
the point where the ops structure is added.

>
>> From 9de02e3617650b6295e584f4ea55512fd12ec68e Mon Sep 17 00:00:00 2001
>> From: Richard Sharpe <realrichardsharpe at gmail.com>
>> Date: Sat, 10 Jan 2015 12:58:37 -0800
>> Subject: [PATCH] Add init and cleanup functions to the registry backends and
>>  call them when them when a registry backend is installed, if they are
>>  defined. If the init function for a new backend fails, we will refuse to
>>  install it to prevent further damage and we print a log level 0 error
>>  message.
>>
>> Signed-off-by: Richard Sharpe <rsharpe at samba.org>
>> ---
>>  source3/include/registry.h       |  3 +++
>>  source3/registry/reg_cachehook.c | 24 ++++++++++++++++++++++++
>>  2 files changed, 27 insertions(+)
>>
>> diff --git a/source3/include/registry.h b/source3/include/registry.h
>> index f7a537e..008046a 100644
>> --- a/source3/include/registry.h
>> +++ b/source3/include/registry.h
>> @@ -40,6 +40,9 @@ struct regsubkey_ctr;
>>   */
>>
>>  struct registry_ops {
>> +     /* Initialize and cleanup the back end, if needed ... */
>> +     int     (*init)(const char *base_key);
>> +     int     (*cleanup)(void);
>>       /* functions for enumerating subkeys and values */
>>       int     (*fetch_subkeys)( const char *key, struct regsubkey_ctr *subkeys);
>>       int     (*fetch_values) ( const char *key, struct regval_ctr *val );
>> diff --git a/source3/registry/reg_cachehook.c b/source3/registry/reg_cachehook.c
>> index 1f26927..ae53096 100644
>> --- a/source3/registry/reg_cachehook.c
>> +++ b/source3/registry/reg_cachehook.c
>> @@ -80,6 +80,7 @@ WERROR reghook_cache_add(const char *keyname, struct registry_ops *ops)
>>  {
>>       WERROR werr;
>>       char *key = NULL;
>> +     struct registry_ops *old_ops;
>>
>>       if ((keyname == NULL) || (ops == NULL)) {
>>               return WERR_INVALID_PARAM;
>> @@ -93,6 +94,29 @@ WERROR reghook_cache_add(const char *keyname, struct registry_ops *ops)
>>       DEBUG(10, ("reghook_cache_add: Adding ops %p for key [%s]\n",
>>                  (void *)ops, key));
>>
>> +     /*
>> +      * If there is already an ops structure registered, call its
>> +      * cleanup function, if any.
>> +      */
>> +     if ((old_ops = pathtree_find(cache_tree, key)) && old_ops->cleanup) {
>> +             DEBUG(10, ("Calling cleanup function for old ops: %p\n",
>> +                     old_ops));
>> +             old_ops->cleanup();
>> +     }
>> +
>> +     /*
>> +      * Call the init function, if it exists ... but if the init
>> +      * function fails, do not install the new ops.
>> +      */
>> +     if (ops->init) {
>> +             if (!ops->init(key)) {
>> +                     DEBUG(0, ("ERROR: Init function failed for ops:key %p:%s, not installed\n",
>> +                             ops, key));
>> +                     werr = WERR_NOMEM; /* Is there something better? */
>> +                     goto done;
>> +             }
>> +     }
>> +
>>       if (!pathtree_add(cache_tree, key, ops))
>>               werr = WERR_NOMEM;
>>       else
>> --
>> 1.8.3.1
>>
>



-- 
Regards,
Richard Sharpe
(何以解憂？唯有杜康。--曹操)
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