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| author | Andrew Tridgell <tridge@samba.org> | 2010-08-16 11:00:41 +1000 |
|---|---|---|
| committer | Andrew Tridgell <tridge@samba.org> | 2010-08-17 08:44:28 +1000 |
| commit | 1cc471d69fc6ff5dc835462b712645415f8feca4 (patch) | |
| tree | 37be411e1c30083d4b94fe96b30219e551998a68 | |
| parent | 68e86969fae55584f12191f09ac0442d09872030 (diff) | |
| download | samba-1cc471d69fc6ff5dc835462b712645415f8feca4.tar.gz samba-1cc471d69fc6ff5dc835462b712645415f8feca4.tar.bz2 samba-1cc471d69fc6ff5dc835462b712645415f8feca4.zip | |
s4-ldb: add some comments explaining the ltdb_index_idxptr() function
this function copes with alignment sensitive CPUs
Signed-off-by: Andrew Bartlett <abartlet@samba.org>
| -rw-r--r-- | source4/lib/ldb/ldb_tdb/ldb_index.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/source4/lib/ldb/ldb_tdb/ldb_index.c b/source4/lib/ldb/ldb_tdb/ldb_index.c index 828dca1f2c..4f5979877b 100644 --- a/source4/lib/ldb/ldb_tdb/ldb_index.c +++ b/source4/lib/ldb/ldb_tdb/ldb_index.c @@ -95,6 +95,11 @@ static int ltdb_dn_list_find_str(struct dn_list *list, const char *dn) return ltdb_dn_list_find_val(list, &v); } +/* + this is effectively a cast function, but with lots of paranoia + checks and also copes with CPUs that are fussy about pointer + alignment + */ static struct dn_list *ltdb_index_idxptr(struct ldb_module *module, TDB_DATA rec, bool check_parent) { struct dn_list *list; @@ -103,6 +108,9 @@ static struct dn_list *ltdb_index_idxptr(struct ldb_module *module, TDB_DATA rec "Bad data size for idxptr %u", (unsigned)rec.dsize); return NULL; } + /* note that we can't just use a cast here, as rec.dptr may + not be aligned sufficiently for a pointer. A cast would cause + platforms like some ARM CPUs to crash */ memcpy(&list, rec.dptr, sizeof(void *)); list = talloc_get_type(list, struct dn_list); if (list == NULL) { |