tdb2: add TDB_RDONLY flag, allow setting/unsetting it.

[ccan] / ccan / tdb2 / tdb.c

diff --git a/ccan/tdb2/tdb.c b/ccan/tdb2/tdb.c
index 7484695d7ab9a8724eb178e82bf3e1a9e52a58e2..bb181732c90a541f832c5f6ea936d218ff7f1c1a 100644 (file)
--- a/ccan/tdb2/tdb.c
+++ b/ccan/tdb2/tdb.c
@@ -324,6 +324,29 @@ unsigned int tdb_get_flags(struct tdb_context *tdb)
        return tdb->flags;
 }
 
+static bool readonly_changable(struct tdb_context *tdb, const char *caller)
+{
+       if (tdb->transaction) {
+               tdb->last_error = tdb_logerr(tdb, TDB_ERR_EINVAL,
+                                            TDB_LOG_USE_ERROR,
+                                            "%s: can't change"
+                                            " TDB_RDONLY inside transaction",
+                                            caller);
+               return false;
+       }
+
+       if (tdb->file->allrecord_lock.count != 0
+           || tdb->file->num_lockrecs != 0) {
+               tdb->last_error = tdb_logerr(tdb, TDB_ERR_EINVAL,
+                                            TDB_LOG_USE_ERROR,
+                                            "%s: can't change"
+                                            " TDB_RDONLY holding locks",
+                                            caller);
+               return false;
+       }
+       return true;
+}
+
 void tdb_add_flag(struct tdb_context *tdb, unsigned flag)
 {
        if (tdb->flags & TDB_INTERNAL) {
@@ -349,6 +372,10 @@ void tdb_add_flag(struct tdb_context *tdb, unsigned flag)
        case TDB_ALLOW_NESTING:
                tdb->flags |= TDB_ALLOW_NESTING;
                break;
+       case TDB_RDONLY:
+               if (readonly_changable(tdb, "tdb_add_flag"))
+                       tdb->flags |= TDB_RDONLY;
+               break;
        default:
                tdb->last_error = tdb_logerr(tdb, TDB_ERR_EINVAL,
                                             TDB_LOG_USE_ERROR,
@@ -382,6 +409,18 @@ void tdb_remove_flag(struct tdb_context *tdb, unsigned flag)
        case TDB_ALLOW_NESTING:
                tdb->flags &= ~TDB_ALLOW_NESTING;
                break;
+       case TDB_RDONLY:
+               if ((tdb->open_flags & O_ACCMODE) == O_RDONLY) {
+                       tdb->last_error = tdb_logerr(tdb, TDB_ERR_EINVAL,
+                                                    TDB_LOG_USE_ERROR,
+                                                    "tdb_remove_flag: can't"
+                                                    " remove TDB_RDONLY on tdb"
+                                                    " opened with O_RDONLY");
+                       break;
+               }
+               if (readonly_changable(tdb, "tdb_remove_flag"))
+                       tdb->flags &= ~TDB_RDONLY;
+               break;
        default:
                tdb->last_error = tdb_logerr(tdb, TDB_ERR_EINVAL,
                                             TDB_LOG_USE_ERROR,