lib-index: Fix assert-crash if cache record has no content after all

This couldn't have happened yet, but will happen after the next commit.

diff --git a/src/lib-index/mail-cache-transaction.c b/src/lib-index/mail-cache-transaction.c
index efad489a519ff6ded5a6bb7ab5b9309cfb24d77c..e9aa87b48298e79b354cc7fa0688e787b2835cc1 100644 (file)
--- a/src/lib-index/mail-cache-transaction.c
+++ b/src/lib-index/mail-cache-transaction.c
@@ -56,7 +56,9 @@ static MODULE_CONTEXT_DEFINE_INIT(cache_mail_index_transaction_module,
                                  &mail_index_module_register);
 
 static int mail_cache_transaction_lock(struct mail_cache_transaction_ctx *ctx);
-static size_t mail_cache_transaction_update_last_rec_size(struct mail_cache_transaction_ctx *ctx);
+static bool
+mail_cache_transaction_update_last_rec_size(struct mail_cache_transaction_ctx *ctx,
+                                           size_t *size_r);
 static int mail_cache_header_rewrite_fields(struct mail_cache *cache);
 
 static void mail_index_transaction_cache_reset(struct mail_index_transaction *t)
@@ -257,7 +259,9 @@ mail_cache_transaction_lookup_rec(struct mail_cache_transaction_ctx *ctx,
        if (seq == ctx->prev_seq && i == count) {
                /* update the unfinished record's (temporary) size and
                   return it */
-               mail_cache_transaction_update_last_rec_size(ctx);
+               size_t size;
+               if (!mail_cache_transaction_update_last_rec_size(ctx, &size))
+                       return NULL;
                return CONST_PTR_OFFSET(ctx->cache_data->data,
                                        ctx->last_rec_pos);
        }
@@ -531,8 +535,9 @@ mail_cache_transaction_drop_unwanted(struct mail_cache_transaction_ctx *ctx,
        buffer_delete(ctx->cache_data, 0, deleted_space);
 }
 
-static size_t
-mail_cache_transaction_update_last_rec_size(struct mail_cache_transaction_ctx *ctx)
+static bool
+mail_cache_transaction_update_last_rec_size(struct mail_cache_transaction_ctx *ctx,
+                                           size_t *size_r)
 {
        struct mail_cache_record *rec;
        void *data;
@@ -541,8 +546,11 @@ mail_cache_transaction_update_last_rec_size(struct mail_cache_transaction_ctx *c
        data = buffer_get_modifiable_data(ctx->cache_data, &size);
        rec = PTR_OFFSET(data, ctx->last_rec_pos);
        rec->size = size - ctx->last_rec_pos;
+       if (rec->size == sizeof(*rec))
+               return FALSE;
        i_assert(rec->size > sizeof(*rec));
-       return rec->size;
+       *size_r = rec->size;
+       return TRUE;
 }
 
 static void
@@ -551,8 +559,8 @@ mail_cache_transaction_update_last_rec(struct mail_cache_transaction_ctx *ctx)
        struct mail_cache_transaction_rec *trans_rec;
        size_t size;
 
-       size = mail_cache_transaction_update_last_rec_size(ctx);
-       if (size > ctx->cache->index->optimization_set.cache.record_max_size) {
+       if (!mail_cache_transaction_update_last_rec_size(ctx, &size) ||
+           size > ctx->cache->index->optimization_set.cache.record_max_size) {
                buffer_set_used_size(ctx->cache_data, ctx->last_rec_pos);
                return;
        }