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inserted additional checks for null values, comments

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fixed deadlocks
This commit is contained in:
Will Ballantyne 1999-02-04 00:21:57 +00:00
parent 5934367242
commit be9e28907e
1 changed files with 97 additions and 22 deletions
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119
servers/slapd/back-ldbm/alias.c
View file

@ -21,17 +21,21 @@
/*
* given an alias object, dereference it to its end point.
* entry returned has reader lock
* Entry returned has reader lock or is NULL. Starting entry is not released.
*/
Entry *derefAlias_r ( Backend *be,
Connection *conn,
Operation *op,
Entry *e)
{
struct ldbminfo *li = (struct ldbminfo *) be->be_private; /* to free cache entries */
Attribute *a;
int depth;
char **pastAliases;
char *matched;
Entry *origDN = e;
if (!e) return NULL; /* be sure we have a starting entry */
Debug( LDAP_DEBUG_TRACE, "<= checking for alias for dn %s\n", e->e_dn, 0, 0 );
@ -55,7 +59,40 @@ Entry *derefAlias_r ( Backend *be,
Debug( LDAP_DEBUG_TRACE, "<= %s is an alias for %s\n",
e->e_dn, a->a_vals[0]->bv_val, 0 );
newDN = ch_strdup (a->a_vals[0]->bv_val);
oldDN = ch_strdup (e->e_dn);
oldDN = ch_strdup (e->e_ndn);
/*
* release past lock if not original
*/
if ( (depth > 0) && e ) {
cache_return_entry_r(&li->li_cache, e);
}
/* make sure new and old DN are not same to avoid loops */
dn_normalize_case (newDN);
if ( strcmp (newDN, oldDN) == 0 ) {
Debug( LDAP_DEBUG_TRACE,
"<= %s alias is same as current %s\n",
oldDN, newDN, 0 );
send_ldap_result( conn, op, LDAP_ALIAS_PROBLEM, "",
"Circular alias" );
free (newDN);
free (oldDN);
break;
}
/* make sure new and original are not same to avoid deadlocks */
if ( strcmp (newDN, origDN->e_ndn) == 0 ) {
Debug( LDAP_DEBUG_TRACE,
"<= %s alias is same as original %s\n",
oldDN, origDN->e_ndn, 0 );
send_ldap_result( conn, op, LDAP_ALIAS_PROBLEM, "",
"Circular alias" );
free (newDN);
free (oldDN);
break;
}
/*
* ok, so what happens if there is an alias in the DN of a dereferenced
@ -67,11 +104,15 @@ Entry *derefAlias_r ( Backend *be,
Debug( LDAP_DEBUG_TRACE,
"<= %s is a dangling alias to %s\n",
oldDN, newDN, 0 );
send_ldap_result( conn, op, LDAP_ALIAS_PROBLEM, "",
send_ldap_result( conn, op, LDAP_ALIAS_DEREF_PROBLEM, "",
"Dangling Alias" );
if(matched != NULL) free(matched);
if (matched != NULL) free(matched);
free (newDN);
free (oldDN);
break;
}
free (newDN);
free (oldDN);
}
@ -82,9 +123,10 @@ Entry *derefAlias_r ( Backend *be,
*/
Debug( LDAP_DEBUG_TRACE,
"<= %s has no data in aliasedobjectname attribute\n",
e->e_dn, 0, 0 );
(e && e->e_dn) ? e->e_dn : "(null)", 0, 0 );
send_ldap_result( conn, op, LDAP_ALIAS_PROBLEM, "",
"Alias missing aliasedobjectname" );
break;
}
}
@ -93,9 +135,11 @@ Entry *derefAlias_r ( Backend *be,
*/
if ( depth >= be->be_maxDerefDepth ) {
Debug( LDAP_DEBUG_TRACE,
"<= %s exceeded maximum deref depth %d\n",
e->e_dn, be->be_maxDerefDepth, 0 );
send_ldap_result( conn, op, LDAP_ALIAS_PROBLEM, "",
"<= deref(\"%s\") exceeded maximum deref depth (%d) at \"%s\"\n",
origDN->e_dn ? origDN->e_dn : "(null)",
be->be_maxDerefDepth,
(e && e->e_ndn) ? e->e_ndn : "(null)");
send_ldap_result( conn, op, LDAP_ALIAS_DEREF_PROBLEM, "",
"Maximum alias dereference depth exceeded" );
}
@ -104,6 +148,17 @@ Entry *derefAlias_r ( Backend *be,
/*
* given a DN fully deref it and return the real DN or original DN if it fails
* This involves finding the last matched part then reconstructing forward
* e.g.
* ou=MyOU,o=MyAliasedOrg,c=MyCountry where o=MyAliasedOrg is an alias for o=MyOrg
* loop starts with newDN = ou=MyOU,o=MyAliasedOrg,c=MyCountry
* dn2entry_r on newDN gives null entry and o=MyAliasedOrg,c=MyCountry matched
* dn2entry_r on matched gives o=MyAliasedOrg,c=MyCountry entry
* remainder is ou=MyOU
* dereferencing o=MyAliasedOrg,c=MyCountry yields entry o=MyOrg,c=MyCountry
* release lock on o=MyAliasedOrg,c=MyCountry entry
* reconstructed dn is ou=MyOU,o=MyOrg,c=MyCountry
* release lock on o=MyOrg,c=MyCountry entry
*/
char *derefDN ( Backend *be,
Connection *conn,
@ -119,6 +174,7 @@ char *derefDN ( Backend *be,
Entry *eDeref;
Entry *eNew;
if (!dn) return NULL;
Debug( LDAP_DEBUG_TRACE,
"<= dereferencing dn: \"%s\"\n",
@ -134,7 +190,7 @@ char *derefDN ( Backend *be,
if ((matched != NULL) && *matched) {
char *submatch;
/*
* make sure there actually is an entry for the matched part
*/
@ -157,6 +213,9 @@ char *derefDN ( Backend *be,
newDN = NULL;
free (remainder);
remainder = NULL;
cache_return_entry_r(&li->li_cache, eMatched);
eMatched = NULL;
break; /* no associated entry, dont deref */
}
else {
@ -166,13 +225,18 @@ char *derefDN ( Backend *be,
i = strcasecmp (matched, eNew->e_dn);
/* free reader lock */
cache_return_entry_r(&li->li_cache, eNew);
free (matched);
matched = NULL;
if (! i) {
/* newDN same as old so not an alias, no need to go further */
free (newDN);
newDN = NULL;
free (matched);
matched = NULL;
free (remainder);
cache_return_entry_r(&li->li_cache, eMatched);
eMatched = NULL;
break;
}
@ -186,12 +250,10 @@ char *derefDN ( Backend *be,
strcat (newDN, eMatched->e_dn);
Debug( LDAP_DEBUG_TRACE, "<= expanded to %s\n", newDN, 0, 0 );
free (matched);
matched = NULL;
free (remainder);
}
/* free reader lock */
cache_return_entry_r(&li->li_cache, eMatched);
/* free reader lock */
cache_return_entry_r(&li->li_cache, eMatched);
}
else {
if(submatch != NULL) free(submatch);
@ -203,14 +265,18 @@ char *derefDN ( Backend *be,
}
}
/* release lock if a match terminated the loop, there should be no
* outstanding locks at this point
*/
if(eMatched != NULL) {
/* free reader lock */
cache_return_entry_r(&li->li_cache, eMatched);
}
/*
* the final part of the DN might be an alias
* so try to dereference it.
* the final part of the DN might be an alias so try to dereference it.
* e.g. if we had started with dn = o=MyAliasedOrg,c=MyCountry the dn would match
* and the above loop complete but we would still be left with an aliased DN.
*/
if ( (eNew = dn2entry_r( be, newDN, &matched )) != NULL) {
if ((eDeref = derefAlias_r( be, conn, op, eNew )) != NULL) {
@ -222,15 +288,25 @@ char *derefDN ( Backend *be,
/* free reader lock */
cache_return_entry_r(&li->li_cache, eNew);
}
if (matched != NULL) free(matched);
/*
* warn if we exceeded the max depth as the resulting DN may not be dereferenced
*/
if (depth >= be->be_maxDerefDepth) {
Debug( LDAP_DEBUG_TRACE,
"<= max deref depth exceeded in derefDN for \"%s\", result \"%s\"\n",
dn, newDN, 0 );
send_ldap_result( conn, op, LDAP_ALIAS_PROBLEM, "",
if (newDN) {
Debug( LDAP_DEBUG_TRACE,
"<= max deref depth exceeded in derefDN for \"%s\", result \"%s\"\n",
dn, newDN, 0 );
free (newDN);
newDN = NULL;
}
else {
Debug( LDAP_DEBUG_TRACE,
"<= max deref depth exceeded in derefDN for \"%s\", result NULL\n",
dn, 0, 0 );
}
send_ldap_result( conn, op, LDAP_ALIAS_DEREF_PROBLEM, "",
"Maximum alias dereference depth exceeded for base" );
}
@ -239,7 +315,6 @@ char *derefDN ( Backend *be,
}
Debug( LDAP_DEBUG_TRACE, "<= returning deref DN of \"%s\"\n", newDN, 0, 0 );
if (matched != NULL) free(matched);
return newDN;
}