[SSSD] [PATCH] SYSDB: sysdb_search_object_by_sid returns ENOENT

Lukas Slebodnik lslebodn at redhat.com
Wed Dec 10 14:24:27 UTC 2014


On (10/12/14 14:48), Pavel Reichl wrote:
>
>On 12/10/2014 02:30 PM, Lukas Slebodnik wrote:
>>On (10/12/14 11:31), Pavel Reichl wrote:
>>>On 12/10/2014 10:25 AM, Lukas Slebodnik wrote:
>>>>On (10/12/14 10:09), Pavel Reichl wrote:
>>>>>On 12/10/2014 09:28 AM, Lukas Slebodnik wrote:
>>>>>>On (09/12/14 12:13), Pavel Reichl wrote:
>>>>>>>On 12/02/2014 12:50 PM, Lukas Slebodnik wrote:
>>>>>>>>On (29/10/14 17:17), Pavel Reichl wrote:
>>>>>>>>>Hello,
>>>>>>>>>
>>>>>>>>>please see attached patch.
>>>>>>>>>
>>>>>>>>>This patch is part of solution for
>>>>>>>>>https://fedorahosted.org/sssd/ticket/1991
>>>>>>>>>which aims to unify return values of sysdb calls in case no results are
>>>>>>>>>found.
>>>>>>>>>
>>>>>>>>a) this patch cannot be applied on current master.
>>>>>>>rebased
>>>>>>>>b) I wrote similar patch becuse sssd_be crashed in function
>>>>>>>>     get_object_from_cache. sysdb_search_object_by_sid didn' returned ENOENT and
>>>>>>>>     res->msgs was NULL (result: dereference of NULL pointer)
>>>>>>>>     -- it is yet another result of broken IPA <-> AD trust
>>>>>>>>c) Could you compare your version and mine?
>>>>>>>>     Feel free to include my patch to yours if it is not good enogh.
>>>>>>>I don't say it was not good enough but I updated my patch.
>>>>>>>>d) test test_sysdb_delete_by_sid seems to be unrelated to this patch.
>>>>>>>>    I would prefer to have it in separete patch.
>>>>>>>I have moved it to separate patch. This patch is just to verify that
>>>>>>>sysdb_delete_by_sid() was not changed by the second patch.
>>>>>>>>LS
>>>>>>>>
>>>>>>>Thanks, please see updated patches.
>>>>>>>From 53c3be375eff41dc70e17bb9e079ec98b8c2c5e7 Mon Sep 17 00:00:00 2001
>>>>>>>From: Pavel Reichl <preichl at redhat.com>
>>>>>>>Date: Tue, 9 Dec 2014 09:47:11 +0000
>>>>>>>Subject: [PATCH 1/2] TESTS: sysdb_delete_by_sid() test return value
>>>>>>>
>>>>>>>Check that return value of sysdb_delete_by_sid() is not changed as
>>>>>>>called SYSDB functions have changed the return value.
>>>>>>>
>>>>>>>Part of patches for:
>>>>>>>https://fedorahosted.org/sssd/ticket/1991
>>>>>>>---
>>>>>>LGTM
>>>>>>
>>>>>>>From 1cb395244d3ab3906af5b6c8b294e80055ad0a07 Mon Sep 17 00:00:00 2001
>>>>>>>From: Pavel Reichl <preichl at redhat.com>
>>>>>>>Date: Tue, 9 Dec 2014 11:01:13 +0000
>>>>>>>Subject: [PATCH 2/2] SYSDB: sysdb_search_object_by_sid returns ENOENT
>>>>>>>
>>>>>>>sysdb_search_object_by_sid returns ENOENT if no results are found.
>>>>>>>
>>>>>>>Part od solution for:
>>>>>>>https://fedorahosted.org/sssd/ticket/1991
>>>>>>>---
>>>>>>>src/db/sysdb.h                 |  2 +-
>>>>>>>src/db/sysdb_ops.c             | 70 ++++++------------------------------------
>>>>>>>src/responder/nss/nsssrv_cmd.c | 27 ++++++++--------
>>>>>>>src/responder/pac/pacsrv_cmd.c | 26 ++++++++++------
>>>>>>>src/tests/sysdb-tests.c        |  5 +--
>>>>>>>5 files changed, 42 insertions(+), 88 deletions(-)
>>>>>>>
>>>>>>>diff --git a/src/db/sysdb.h b/src/db/sysdb.h
>>>>>>>index 5bd7f90acb685bbaff5c98f433c7dce8175c33ca..9b88b4a63619456f8f3cc1961e29bbf3946ca5b8 100644
>>>>>>>--- a/src/db/sysdb.h
>>>>>>>+++ b/src/db/sysdb.h
>>>>>>>@@ -1033,7 +1033,7 @@ errno_t sysdb_search_object_by_sid(TALLOC_CTX *mem_ctx,
>>>>>>>                                    struct sss_domain_info *domain,
>>>>>>>                                    const char *sid_str,
>>>>>>>                                    const char **attrs,
>>>>>>>-                                   struct ldb_result **msg);
>>>>>>>+                                   struct ldb_result **res);
>>>>>>>
>>>>>>>errno_t sysdb_search_object_by_uuid(TALLOC_CTX *mem_ctx,
>>>>>>>                                     struct sss_domain_info *domain,
>>>>>>>diff --git a/src/db/sysdb_ops.c b/src/db/sysdb_ops.c
>>>>>>>index 998046a2ca1c746b2032f430e5f9c4a7151e1dbc..8d6b11c248fd7f895ff6a95c25d4372fc7f8445d 100644
>>>>>>>--- a/src/db/sysdb_ops.c
>>>>>>>+++ b/src/db/sysdb_ops.c
>>>>>>>@@ -2995,8 +2995,15 @@ int sysdb_delete_by_sid(struct sysdb_ctx *sysdb,
>>>>>>>
>>>>>>>     ret = sysdb_search_object_by_sid(tmp_ctx, domain, sid_str, NULL, &res);
>>>>>>>     if (ret != EOK) {
>>>>>>>-        DEBUG(SSSDBG_OP_FAILURE, "search by sid failed: %d (%s)\n",
>>>>>>>-              ret, strerror(ret));
>>>>>>>+        if (ret == ENOENT) {
>>>>>>>+            /* No existing entry. Just quit. */
>>>>>>>+            DEBUG(SSSDBG_TRACE_FUNC,
>>>>>>>+                  "search by sid did not return any results.\n");
>>>>>>>+            ret = EOK;
>>>>>>>+        } else {
>>>>>>>+            DEBUG(SSSDBG_OP_FAILURE, "search by sid failed: %d (%s)\n",
>>>>>>>+                  ret, strerror(ret));
>>>>>>>+        }
>>>>>>>         goto done;
>>>>>>I'm sorry but this isn't very readable.
>>>>>>I prefer flat version.
>>>>>>If/else if/else is easier to read and if you want to do micro optimisation
>>>>>>then you can use switch case.
>>>>>I find it better readable this way - errors are handled in single block. It's
>>>>>not against any code style rules I'm aware of. But I suppose if this is the
>>>>>only way to get the patches pushed I'll do it your preferred way...
>>>>The problem is that I need to spend a lot of time with "parsing this code"
>>>>Someone can overlook goto done in this case and introduce a bug.
>>>>Your solution isn't bad but it isn't straightforward.
>>>>
>>>>This is especially problem in pac responder.
>>>>There are 3 nested levels of if. WHY?
>>>>I'm sorry but I can lost easily there.
>>>>
>>>>      ret = sysdb_search_object_by_sid(cmdctx, dom, cmdctx->secid, NULL,
>>>>                                       &dctx->res);
>>>>      if (ret != EOK) {
>>>>         if (ret == ENOENT) {
>>>>             if (!dctx->check_provider) {
>>>>                 DEBUG(SSSDBG_OP_FAILURE, "No results for getbysid call.\n");
>>>>
>>>>                 /* set negative cache only if not result of cache check */
>>>>                 ret = sss_ncache_set_sid(nctx->ncache, false, cmdctx->secid);
>>>>                 if (ret != EOK) {
>>>>                     DEBUG(SSSDBG_MINOR_FAILURE,
>>>>                           "Cannot set negative cache for %s\n", cmdctx->secid);
>>>>                 }
>>>>             }
>>>>             return ENOENT;
>>>>         }
>>>>         DEBUG(SSSDBG_CRIT_FAILURE, "Failed to make request to our cache!\n");
>>>>         return EIO;
>>>>     }
>>>>
>>>>//snip
>>>>
>>>>>>>@@ -912,9 +913,14 @@ pac_store_membership(struct pac_req_ctx *pr_ctx,
>>>>>>>     ret = sysdb_search_object_by_sid(tmp_ctx, grp_dom, grp_sid_str,
>>>>>>>                                      group_attrs, &group);
>>>>>>>     if (ret != EOK) {
>>>>>>>-        DEBUG(SSSDBG_TRACE_INTERNAL, "sysdb_search_object_by_sid " \
>>>>>>>-                                      "for SID [%s] failed [%d][%s].\n",
>>>>>>>-                                      grp_sid_str, ret, strerror(ret));
>>>>>>>+        if (ret == ENOENT) {
>>>>>>>+            DEBUG(SSSDBG_OP_FAILURE, "Unexpected number of groups returned.\n");
>>>>>>>+            ret = EINVAL;
>>>>                 ^^^^^^^^^^^^^
>>>>             I found another interesting part.
>>>>Why do you override ENOENT with EINVAL. ENOENT (msg->count == 0) was not
>>>>special cased before your change.
>>>Please again see context:
>>>Before changing sysdb_search_object_by_sid() to return ENOENT on no result
>>>EOK was returned and condition '(group->count != 1)' was true in that case.
>>>So I just kept this behaviour. Is that clear now?
>>Ahh I see. I overlook != 1 I was looking for  == 0.
>>
>>but still it would be better to return ENOENT. So we can distinguish between
>>group->count == 0 and group->count > 1. It should not happen very.
>>
>>LS
>hmm sounds right, I just check the calling side...and then update the patch
>as you proposed.
>
>Michal would you be so kind to arbitrate mine and Lukas' little dispute about
>the nesting ifs? Just say what would you prefer.
>
+1 for different opinions.

LS



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