util: util_ntdb ntdb_fetch_int32/ntdb_store_int32 and ntdb_add_int32_atomic

Similar to the util_tdb versions, but return the error code.

ntdb_add_int32_atomic seems a clearer name than tdb_change_int32_atomic.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

2 files changed, 89 insertions, 0 deletions

diff --git a/lib/util/util_ntdb.c b/lib/util/util_ntdb.c
index ad9e0a73d2..be720e55a6 100644
--- a/lib/util/util_ntdb.c
+++ b/lib/util/util_ntdb.c
@@ -237,6 +237,71 @@ enum NTDB_ERROR ntdb_fetch_bystring(struct ntdb_context *ntdb,
 	return ntdb_fetch(ntdb, key, data);
 }
 
+enum NTDB_ERROR ntdb_fetch_int32(struct ntdb_context *ntdb,
+				 const char *keystr, int32_t *val)
+{
+	NTDB_DATA data;
+	enum NTDB_ERROR err;
+
+	err = ntdb_fetch(ntdb, string_term_ntdb_data(keystr), &data);
+	if (err == NTDB_SUCCESS) {
+		if (data.dsize != sizeof(*val)) {
+			err = NTDB_ERR_CORRUPT;
+		} else {
+			*val = IVAL(data.dptr,0);
+		}
+		talloc_free(data.dptr);
+	}
+	return NTDB_SUCCESS;
+}
+
+enum NTDB_ERROR ntdb_store_int32(struct ntdb_context *ntdb,
+				 const char *keystr, int32_t val)
+{
+	NTDB_DATA data, key;
+	int32_t v_store;
+
+	SIVAL(&v_store, 0, val);
+	data = ntdb_mkdata(&v_store, sizeof(v_store));
+	key = string_term_ntdb_data(keystr);
+
+	return ntdb_store(ntdb, key, data, NTDB_REPLACE);
+}
+
+enum NTDB_ERROR ntdb_add_int32_atomic(struct ntdb_context *ntdb,
+				      const char *keystr,
+				      int32_t *oldval, int32_t addval)
+{
+	int32_t val;
+	enum NTDB_ERROR err;
+
+	err = ntdb_lock_bystring(ntdb, keystr);
+	if (err) {
+		return err;
+	}
+
+	err = ntdb_fetch_int32(ntdb, keystr, &val);
+	if (err) {
+		if (err == NTDB_ERR_NOEXIST) {
+			/* Start with 'old' value */
+			val = *oldval;
+		} else {
+			goto err_out;
+		}
+	} else {
+		/* It worked, set return value (oldval) to tdb data */
+		*oldval = val;
+	}
+
+	/* Increase value and store for next time. */
+	val += addval;
+	err = ntdb_store_int32(ntdb, keystr, val);
+
+  err_out:
+	ntdb_unlock_bystring(ntdb, keystr);
+	return err;
+}
+
 NTSTATUS map_nt_error_from_ntdb(enum NTDB_ERROR err)
 {
 	NTSTATUS result = NT_STATUS_INTERNAL_ERROR;
diff --git a/lib/util/util_ntdb.h b/lib/util/util_ntdb.h
index eac0db4f02..7531c42dee 100644
--- a/lib/util/util_ntdb.h
+++ b/lib/util/util_ntdb.h
@@ -96,6 +96,30 @@ enum NTDB_ERROR ntdb_fetch_bystring(struct ntdb_context *ntdb,
 
 
 /****************************************************************************
+ Fetch a int32_t value by a string key.  *val is int32_t in native byte order.
+ ntdb must have been created with ntdb_new() (as it uses talloc_free).
+****************************************************************************/
+enum NTDB_ERROR ntdb_fetch_int32(struct ntdb_context *ntdb,
+				 const char *keystr, int32_t *val);
+
+/****************************************************************************
+ Store a int32_t value by a string key.  val is int32_t in native byte order.
+****************************************************************************/
+enum NTDB_ERROR ntdb_store_int32(struct ntdb_context *ntdb,
+				 const char *keystr, int32_t val);
+
+
+/****************************************************************************
+ Atomic integer add; reads the old value into *oldval (if found), then stores
+ *oldval + addval back for next time.  Uses chainlock to do this atomically.
+
+ Thus the first time this is ever called, oldval will be unchanged.
+****************************************************************************/
+enum NTDB_ERROR ntdb_add_int32_atomic(struct ntdb_context *ntdb,
+				      const char *keystr,
+				      int32_t *oldval, int32_t addval);
+
+/****************************************************************************
  Turn a nul-terminated string into an NTDB_DATA.
 ****************************************************************************/
 static inline NTDB_DATA string_term_ntdb_data(const char *string)