AUTOFS: allow removing entries from hash table

There is a timed desctructor in the autofs responder that, when the
entry timeout passes, removes the autofs map from the hash table while
the map is freed. This patch adds a hash delete callback so that if the
map is removed from the hash table with hash_delete, its hash table
pointer will be invalidated. Later, when the entry is being freed, the
destructor won't attempt to remove it from the hash table.

3 files changed, 32 insertions, 1 deletions

diff --git a/src/responder/autofs/autofs_private.h b/src/responder/autofs/autofs_private.h
index bb0c6189..a2af36e4 100644
--- a/src/responder/autofs/autofs_private.h
+++ b/src/responder/autofs/autofs_private.h
@@ -76,6 +76,9 @@ struct autofs_map_ctx {
 
 struct sss_cmd_table *get_autofs_cmds(void);
 
+void autofs_map_hash_delete_cb(hash_entry_t *item,
+                               hash_destroy_enum deltype, void *pvt);
+
 enum sss_dp_autofs_type {
     SSS_DP_AUTOFS
 };
diff --git a/src/responder/autofs/autofssrv.c b/src/responder/autofs/autofssrv.c
index 86a816a3..d7c10d6c 100644
--- a/src/responder/autofs/autofssrv.c
+++ b/src/responder/autofs/autofssrv.c
@@ -158,7 +158,8 @@ autofs_process_init(TALLOC_CTX *mem_ctx,
     }
 
     /* Create the lookup table for setautomntent results */
-    hret = sss_hash_create(autofs_ctx, 10, &autofs_ctx->maps);
+    hret = sss_hash_create_ex(autofs_ctx, 10, &autofs_ctx->maps, 0, 0, 0, 0,
+                              autofs_map_hash_delete_cb, NULL);
     if (hret != HASH_SUCCESS) {
         DEBUG(SSSDBG_CRIT_FAILURE,
               ("Unable to initialize automount maps hash table\n"));
diff --git a/src/responder/autofs/autofssrv_cmd.c b/src/responder/autofs/autofssrv_cmd.c
index 3af4a846..0cfdbec5 100644
--- a/src/responder/autofs/autofssrv_cmd.c
+++ b/src/responder/autofs/autofssrv_cmd.c
@@ -118,6 +118,27 @@ get_autofs_map(struct autofs_ctx *actx,
 
 static int autofs_map_hash_remove (TALLOC_CTX *ctx);
 
+void
+autofs_map_hash_delete_cb(hash_entry_t *item,
+                          hash_destroy_enum deltype, void *pvt)
+{
+    struct autofs_map_ctx *map;
+
+    if (deltype != HASH_ENTRY_DESTROY) {
+        return;
+    }
+
+    map = talloc_get_type(item->value.ptr, struct autofs_map_ctx);
+    if (!map) {
+        DEBUG(SSSDBG_OP_FAILURE, ("Invalid autofs map\n"));
+        return;
+    }
+
+    /* So that the destructor wouldn't attempt to remove the map from hash
+     * table */
+    map->map_table = NULL;
+}
+
 static errno_t
 set_autofs_map(struct autofs_ctx *actx,
                struct autofs_map_ctx *map)
@@ -158,6 +179,12 @@ autofs_map_hash_remove(TALLOC_CTX *ctx)
     struct autofs_map_ctx *map =
             talloc_get_type(ctx, struct autofs_map_ctx);
 
+    if (map->map_table == NULL) {
+        DEBUG(SSSDBG_TRACE_LIBS, ("autofs map [%s] was already removed\n",
+              map->mapname));
+        return 0;
+    }
+
     key.type = HASH_KEY_STRING;
     key.str = map->mapname;