Examples of errors detected by the V654 diagnostic

V654. The condition of loop is always true/false.

Apache HTTP Server

V654 The condition 'retry < 2' of loop is always true. mod_proxy_wstunnel mod_proxy_wstunnel.c 436

static int proxy_wstunnel_handler(....)
{
  int retry;
  ....
  retry = 0;
  while (retry < 2) {
    char *locurl = url;
    ....
    // Variable 'retry' is not used
    ....
  }
  ....
}

WebRTC

V654 The condition 'loopCnt < 5' of loop is always true. cpr_win_socket.c 746

#define TCP_PORT_RETRY_CNT  5

cpr_socket_t
cprSecSocConnect (char *host,
                  int     port,
                  int     ipMode,
                  boolean mode,
                  uint32_t tos,
                  uint16_t *localPort)
{
  ....
  uint16_t loopCnt  = 0;
  ....
  while (loopCnt < TCP_PORT_RETRY_CNT) {
    ....
    .... // loopCnt not changed
    ....
  }
  ....
}

Oracle VM Virtual Box

V654 The condition of loop is always true. suphardenedverifyprocess-win.cpp 1732

DECLHIDDEN(int) supHardNtLdrCacheOpen(const char *pszName, ....)
{
  ....
  uint32_t i = 0;
  while (i < RT_ELEMENTS(g_apszSupNtVpAllowedDlls))
    if (!strcmp(pszName, g_apszSupNtVpAllowedDlls[i]))
      break;
  ....
}

What is dangerous about this loop is that the counter value doesn't change, so if the very first array item doesn't coincide with 'pszName', we'll get an infinite loop.

K Desktop Environment

V654 The condition 'state != 1' of loop is always true. passwd.cpp 255

int PasswdProcess::ConversePasswd(....)
{
  ....
  state = 0;
  while (state != 1)
  {
    line = readLine();
    if (line.isNull())
    {
      // No more input... OK
      return 0;
    }
    if (isPrompt(line, "password"))
    {
      // Uh oh, another prompt. Not good!
      kill(m_Pid, SIGKILL);
      waitForChild();
      return PasswordNotGood;
    }
    m_Error += line + '\n'; // Collect error message
  }
  ....
}

Miranda NG

V654 The condition '5' of loop is always true. Xfire main.cpp 1110

extern "C" __declspec(dllexport) int  Load(void)
{
  ....
  for (i = MAX_PATH; 5; i--){
  ....
}

Similar errors can be found in some other places:

• V654 The condition '5' of loop is always true. Xfire variables.cpp 194

Linux Kernel

V654 The condition 'i < 10' of loop is always true. qla3xxx.c 149

static int ql_wait_for_drvr_lock(struct ql3_adapter *qdev)
{
  int i = 0;

  while (i < 10) {
    if (i)
      ssleep(1);

    if (ql_sem_lock(qdev,
        QL_DRVR_SEM_MASK,
        (QL_RESOURCE_BITS_BASE_CODE | (qdev->mac_index)
         * 2) << 1)) {
      netdev_printk(KERN_DEBUG, qdev->ndev,
              "driver lock acquired\n");
      return 1;
    }
  }

  netdev_err(qdev->ndev,
             "Timed out waiting for driver lock...\n");
  return 0;
}

Unreal Engine 4

V654 The condition '!bFoundName' of loop is always true. edgraphutilities.cpp 244

void FEdGraphUtilities::RenameGraphCloseToName(....)
{
  bool bFoundName = false;

  FString NewName = BaseName;

  int32 NameIndex = StartIndex;
  while (!bFoundName)
  {
    if (Graph->Rename(*NewName, Graph->GetOuter(), REN_Test))
    {
      UBlueprint* BP = FBlueprintEditorUtils....;
      Graph->Rename(*NewName, Graph->GetOuter(), ....);
      return;
    }

    NewName = FString::Printf(TEXT("%s_%d"),*BaseName,NameIndex);
    ++NameIndex;
  }
}

Git

V654 The condition of loop is always false. sha1_file.c 693

void release_pack_memory(size_t need)
{
  size_t cur = pack_mapped;
  while (need >= (cur - pack_mapped) && unuse_one_window(NULL))
    ; /* nothing */
}

EFL Core Libraries

V654 The condition of loop is always false. evas_font_query.c 376

EAPI void
evas_common_font_query_size(....)
{
  ....
  size_t cluster = 0;
  size_t cur_cluster = 0;
  ....
  do
  {
    cur_cluster = cluster + 1;

    glyph--;
    if (cur_w > ret_w)
    {
      ret_w = cur_w;
    }
  }
  while ((glyph > first_glyph) && (cur_cluster == cluster));
  ....
}

Ardour

V654 The condition 'tries < 8' of loop is always true. session_transport.cc 68

void
Session::add_post_transport_work (PostTransportWork ptw)
{
  PostTransportWork oldval;
  PostTransportWork newval;
  int tries = 0;

  while (tries < 8) {
    oldval = (PostTransportWork) g_atomic_int_get (....);
    newval = PostTransportWork (oldval | ptw);
    if (g_atomic_int_compare_and_exchange (....)) {
      /* success */
      return;
    }
  }

  error << "Could not set post transport work! ...." << endmsg;
}

RT-Thread

V654 CWE-834 The condition 'i <= 255' of loop is always true. drv_ft5x06.c 160

static int ft5x06_dump(void)
{
  uint8_t i;
  uint8_t reg_value;

  DEBUG_PRINTF("[FTS] Touch Chip\r\n");

  for (i = 0; i <= 255; i++)
  {
    _ft5x06_read(i, ®_value, 1);

    if (i % 8 == 7)
      DEBUG_PRINTF("0x%02X = 0x%02X\r\n", i, reg_value);
    else
      DEBUG_PRINTF("0x%02X = 0x%02X ", i, reg_value);
  }
  DEBUG_PRINTF("\n");

  return 0;
}

Android

V654 CWE-834 The condition 'gate_id <= 0xFF' of loop is always true. nfa_hci_utils.cc 248

#define NFA_HCI_LAST_PROP_GATE 0xFF

tNFA_HCI_DYN_GATE* nfa_hciu_alloc_gate(uint8_t gate_id,
                                       tNFA_HANDLE app_handle) {
  ....
  for (gate_id = NFA_HCI_FIRST_HOST_SPECIFIC_GENERIC_GATE;
       gate_id <= NFA_HCI_LAST_PROP_GATE; gate_id++) {
    if (gate_id == NFA_HCI_CONNECTIVITY_GATE) gate_id++;
    if (nfa_hciu_find_gate_by_gid(gate_id) == NULL) break;
  }

  if (gate_id > NFA_HCI_LAST_PROP_GATE) {
    LOG(ERROR) << StringPrintf(
        "nfa_hci_alloc_gate - no free Gate ID: %u  "
        "App Handle: 0x%04x", gate_id, app_handle);
    return (NULL);
  }
  ....
}

Android

V654 CWE-834 The condition '++ retries' of loop is always true. SimpleDecodingSource.cpp 226

status_t SimpleDecodingSource::doRead(....) {
  ....
  for (int retries = 0; ++retries; ) {
  ....
}