On 12/20/2012 05:17 PM, Simo Sorce wrote:
On Thu, 2012-12-20 at 17:03 +0100, Pavel Březina wrote:
On 12/20/2012 04:41 PM, Simo Sorce wrote:
On Thu, 2012-12-20 at 16:14 +0100, Pavel Březina wrote:
On 12/20/2012 02:20 PM, Simo Sorce wrote:
On Thu, 2012-12-20 at 12:29 +0100, Pavel Březina wrote:
On 12/20/2012 06:10 AM, Simo Sorce wrote:
-static errno_t sss_mc_get_record(struct sss_mc_ctx *mcc,
+static errno_t sss_mc_get_record(struct sss_mc_ctx **_mcc,
size_t rec_len,
struct sized_string *key,
struct sss_mc_rec **_rec)
{
+ struct sss_mc_ctx *mcc = *_mcc;
struct sss_mc_rec *old_rec = NULL;
struct sss_mc_rec *rec;
int old_slots;
@@ -424,6 +425,16 @@ static errno_t sss_mc_get_record(struct sss_mc_ctx *mcc,
/* we are going to use more space, find enough free slots */
ret = sss_mc_find_free_slots(mcc, num_slots, &base_slot);
if (ret != EOK) {
+ if (ret == EFAULT) {
+ TALLOC_CTX *parent;
+ DEBUG(SSSDBG_CRIT_FAILURE,
+ ("Fatal internal mmap cache error, invalidating cache!\n"));
+ parent = talloc_parent(mcc);
+ if (parent == NULL) {
+ talloc_zfree(*_mcc);
+ }
+ (void)sss_mmap_cache_reinit(parent, -1, -1, _mcc);
+ }
return ret;
}
Hi,
Is if (parent == NULL) only precaution or can it actually happen?
Only a precaution, all the callers use an actual memory context.
If you talloc_zfree(*_mcc) then you will hit EINVAL in reinit() and the
cache won't be reinitialized. Is this intentional? If so, can you
comment it in the code?
Well it was not intentional I meant to return after the free.
However I am wondering if we should really care ...
If the caller had NULL as the parent something may have gone wrong, but
at worst we will leak a few bytes... maybe I shouldn't consider a NULL
parent as an error after all. Opinions ?
Simo.
Does the memory cache require a parent context for some reason (do you
manipulate with the parent within the cache)?
If not I think you should not take care whether is has a parent or not.
For what we know, it may be intentional by the caller. Otherwise you
should check if mem_ctx != NULL in init().
Looking into the init() function I found out that you are using wrong
context:
mc_ctx->name = talloc_strdup(mem_ctx, name);
if (!mc_ctx->name) {
ret = ENOMEM;
goto done;
}
It should say mc_ctx not mem_ctx.
Nice catch.
I also realized that the reinit() function uses talloc_free() instead of
talloc_zfree() on the mc_ctx which would leave a wild pointer to freed
memory in the caller should the init() fail.
So in the attached patch I fixed all this and removed any check about
the talloc_parent(), we just trust it returns the correct value and the
caller did a sensible thing with the first init()
Simo.
Nack.
src/responder/nss/nsssrv_mmap_cache.c: In function ‘sss_mmap_cache_reinit’:
src/responder/nss/nsssrv_mmap_cache.c:1051:11: error: expected
expression before ‘do’
talloc_zfree() doesn't return value (it's inside do...while)
Ouch.
Sorry.
Amended patch attached.
Ack to the code.
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