fw_cfg: prohibit insertion of duplicate fw_cfg file names

Exit with an error (instead of simply logging a trace event)
whenever the same fw_cfg file name is added multiple times via
one of the fw_cfg_add_file[_callback]() host-side API calls.
Signed-off-by: NGabriel Somlo <somlo@cmu.edu>
Reviewed-by: NLaszlo Ersek <lersek@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

hw/nvram/fw_cfg.c

@@ -515,18 +515,19 @@ void fw_cfg_add_file_callback(FWCfgState *s,  const char *filename,
     index = be32_to_cpu(s->files->count);
     assert(index < FW_CFG_FILE_SLOTS);
 
-    fw_cfg_add_bytes_read_callback(s, FW_CFG_FILE_FIRST + index,
-                                   callback, callback_opaque, data, len);
-
     pstrcpy(s->files->f[index].name, sizeof(s->files->f[index].name),
             filename);
     for (i = 0; i < index; i++) {
         if (strcmp(s->files->f[index].name, s->files->f[i].name) == 0) {
-            trace_fw_cfg_add_file_dupe(s, s->files->f[index].name);
-            return;
+            error_report("duplicate fw_cfg file name: %s",
+                         s->files->f[index].name);
+            exit(1);
         }
     }
 
+    fw_cfg_add_bytes_read_callback(s, FW_CFG_FILE_FIRST + index,
+                                   callback, callback_opaque, data, len);
+
     s->files->f[index].size   = cpu_to_be32(len);
     s->files->f[index].select = cpu_to_be16(FW_CFG_FILE_FIRST + index);
     trace_fw_cfg_add_file(s, index, s->files->f[index].name, len);

trace-events

@@ -195,7 +195,6 @@ ecc_diag_mem_readb(uint64_t addr, uint32_t ret) "Read diagnostic %"PRId64"= %02x
 # hw/nvram/fw_cfg.c
 fw_cfg_select(void *s, uint16_t key, int ret) "%p key %d = %d"
 fw_cfg_read(void *s, uint8_t ret) "%p = %d"
-fw_cfg_add_file_dupe(void *s, char *name) "%p %s"
 fw_cfg_add_file(void *s, int index, char *name, size_t len) "%p #%d: %s (%zd bytes)"
 
 # hw/block/hd-geometry.c