/*********************************************************
 * Copyright (c) 2020-2021,2023 VMware, Inc. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation version 2.1 and no later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the Lesser GNU General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA.
 *
 *********************************************************/

/*
 * serviceDiscovery.c --
 *
 * Captures the information about services inside the guest
 * and writes it to either host-side gdp daemon or Namespace DB
 */

#include <string.h>
#include "str.h"

#include "serviceDiscoveryInt.h"
#include "vmware.h"
#include "conf.h"
#include "guestApp.h"
#include "dynbuf.h"
#include "util.h"
#include "vmcheck.h"
#include "vmware/guestrpc/serviceDiscovery.h"
#include "vmware/tools/threadPool.h"
#include "vmware/tools/utils.h"

#include "vmware/tools/guestrpc.h"

#if !defined(__APPLE__)
#include "vm_version.h"
#include "embed_version.h"
#include "vmtoolsd_version.h"
VM_EMBED_VERSION(VMTOOLSD_VERSION_STRING);
#endif

#if defined(_WIN32)
#include <windows.h>
#endif


#define NSDB_PRIV_GET_VALUES_CMD "namespace-priv-get-values"
#define NSDB_PRIV_SET_KEYS_CMD "namespace-priv-set-keys"

#if defined (_WIN32)

#define SCRIPT_EXTN ".ps1"

/*
 * Scripts used by plugin in Windows guests to capture information about
 * running services.
 */
#define SERVICE_DISCOVERY_SCRIPT_PERFORMANCE_METRICS "get-performance-metrics" SCRIPT_EXTN
#define SERVICE_DISCOVERY_WIN_SCRIPT_RELATIONSHIP "get-parent-child-rels" SCRIPT_EXTN
#define SERVICE_DISCOVERY_WIN_SCRIPT_NET "net-share" SCRIPT_EXTN
#define SERVICE_DISCOVERY_WIN_SCRIPT_IIS_PORTS "get-iis-ports-info" SCRIPT_EXTN
#define SERVICE_DISCOVERY_WIN_SCRIPT_SHAREPOINT_PORTS "get-sharepoint-ports-info" SCRIPT_EXTN

#else

#define SCRIPT_EXTN ".sh"

/*
 * Scripts used by plugin in Linux guests to capture information about
 * running services.
 */
#define SERVICE_DISCOVERY_SCRIPT_PERFORMANCE_METRICS \
        "get-listening-process-perf-metrics" SCRIPT_EXTN

#define _get_errno(p) (*p = errno)

#endif

static gchar* scriptInstallDir = NULL;

/*
 * Scripts used by plugin in both Windows and Linux guests to capture
 * information about running services.
 */
#define SERVICE_DISCOVERY_SCRIPT_PROCESSES "get-listening-process-info" SCRIPT_EXTN
#define SERVICE_DISCOVERY_SCRIPT_CONNECTIONS "get-connection-info" SCRIPT_EXTN
#define SERVICE_DISCOVERY_SCRIPT_VERSIONS "get-versions" SCRIPT_EXTN

/*
 * Default value for CONFNAME_SERVICE_DISCOVERY_DISABLED setting in
 * tools configuration file.
 */
#define SERVICE_DISCOVERY_CONF_DEFAULT_DISABLED_VALUE FALSE

/*
 * Polling interval of service discovery plugin in milliseconds
 */
#define SERVICE_DISCOVERY_POLL_INTERVAL 300000

/*
 * Time shift for comparison of time read from the signal and
 * current system time in milliseconds.
 */
#define SERVICE_DISCOVERY_WRITE_DELTA 60000

/*
 * Time to wait in milliseconds before RPC operation
 */
#define SERVICE_DISCOVERY_RPC_WAIT_TIME 100

/*
 * Defines the configuration to cache data in gdp plugin
 */
#define CONFNAME_SERVICEDISCOVERY_CACHEDATA "cache-data"
#define SERVICE_DISCOVERY_CONF_DEFAULT_CACHEDATA TRUE

/*
 * Define the configuration to require at least one subscriber subscribed for
 * the gdp message.
 *
 * TODO: SD maintainer to update default to TRUE when ready.
 */
#define CONFNAME_SERVICEDISCOVERY_REQUIRESUBS "require-subscribers"
#define SERVICE_DISCOVERY_CONF_DEFAULT_REQUIRESUBS FALSE

#define SERVICE_DISCOVERY_TOPIC_PREFIX "serviceDiscovery"

#if defined(VMX86_DEBUG)
/*
 * Defines the configuration to identify whether is in GDP debug mode
 *
 * Tools daemon restart is required to apply this setting's change
 */
#define CONFNAME_SERVICEDISCOVERY_GDP_DEBUG "gdp-debug"

/*
 * Defines the configuration to customize polling interval for GDP debug
 *
 * Tools daemon restart is required to apply this setting's change
 */
#define CONFNAME_SERVICEDISCOVERY_GDP_POLL_INTERVAL "poll-interval"

/*
 * Default polling interval of service discovery plugin for GDP debug in seconds
 */
#define SERVICE_DISCOVERY_CONF_GDP_DEBUG_POLL_INTERVAL 15

/*
 * Minimum polling interval of service discovery plugin for GDP debug in seconds
 */
#define SERVICE_DISCOVERY_CONF_MIN_POLL_INTERVAL 1

static Bool isGDPDebug = FALSE;
#endif

/*
 * Maximum number of keys that can be deleted by one operation
 */
#define SERVICE_DISCOVERY_DELETE_CHUNK_SIZE 25

/*
 * GdpError message table.
 * From GDP_ERR_ITEM tuple:
 *   - GdpEnum name
 *   - error-id string id
 *   - Default error message string
 */
#define GDP_ERR_ITEM(a, b, c) c,
static const char * const gdpErrMsgs[] = {
GDP_ERR_LIST
};
#undef GDP_ERR_ITEM

typedef struct {
   gchar *keyName;
   gchar *val;
} KeyNameValue;

static KeyNameValue gKeyScripts[] = {
   { SERVICE_DISCOVERY_KEY_PROCESSES, SERVICE_DISCOVERY_SCRIPT_PROCESSES },
   { SERVICE_DISCOVERY_KEY_CONNECTIONS,
     SERVICE_DISCOVERY_SCRIPT_CONNECTIONS },
   { SERVICE_DISCOVERY_KEY_PERFORMANCE_METRICS,
     SERVICE_DISCOVERY_SCRIPT_PERFORMANCE_METRICS },
   { SERVICE_DISCOVERY_KEY_VERSIONS, SERVICE_DISCOVERY_SCRIPT_VERSIONS },
#if defined(_WIN32)
   { SERVICE_DISCOVERY_WIN_KEY_RELATIONSHIP,
     SERVICE_DISCOVERY_WIN_SCRIPT_RELATIONSHIP },
   { SERVICE_DISCOVERY_WIN_KEY_IIS_PORTS,
     SERVICE_DISCOVERY_WIN_SCRIPT_IIS_PORTS },
   { SERVICE_DISCOVERY_WIN_KEY_SHAREPOINT_PORTS,
     SERVICE_DISCOVERY_WIN_SCRIPT_SHAREPOINT_PORTS },
   { SERVICE_DISCOVERY_WIN_KEY_NET, SERVICE_DISCOVERY_WIN_SCRIPT_NET },
#endif
};

static GSource *gServiceDiscoveryTimeoutSource = NULL;
static gint64 gLastWriteTime = 0;

static GArray *gFullPaths = NULL;
static Atomic_Bool gTaskSubmitted = { FALSE }; // Task has been submitted.

static size_t readBytesPerCycle = 0;
static size_t cycle = 0;
static Bool isGDPWriteReady = TRUE;
static Bool isNDBWriteReady = TRUE;

static Bool gSkipThisTask = FALSE; // Skip this task on some gdp errors.

/*
 *****************************************************************************
 * GetGuestTimeInMillis --
 *
 * Get system current time in millis.
 *
 * @retval time in millis.
 *
 *****************************************************************************
 */

static gint64
GetGuestTimeInMillis(void)
{
   return g_get_real_time() / 1000;
}

#if defined(VMX86_DEBUG)
/*
 *****************************************************************************
 * GetGDPPollInterval --
 *
 * @brief Get poll interval from tools config for debugging the GDP
 *
 * @param[in]  ctx     The application context
 *
 * @retval Poll interval in milli-seconds.
 *
 *****************************************************************************
 */

static gint
GetGDPPollInterval(ToolsAppCtx *ctx)
{
   gint pollInterval =
      VMTools_ConfigGetInteger(ctx->config,
                               CONFGROUPNAME_SERVICEDISCOVERY,
                               CONFNAME_SERVICEDISCOVERY_GDP_POLL_INTERVAL,
                               SERVICE_DISCOVERY_CONF_GDP_DEBUG_POLL_INTERVAL);
   if (pollInterval < SERVICE_DISCOVERY_CONF_MIN_POLL_INTERVAL) {
      g_info("%s: Service discovery minimum poll interval is enforced.\n",
             __FUNCTION__);
      pollInterval = SERVICE_DISCOVERY_CONF_MIN_POLL_INTERVAL;
   }

   return pollInterval * 1000;
}
#endif

/*
 *****************************************************************************
 * SendRpcMessage --
 *
 * Sends message over RPC channel.
 *
 * @param[in] ctx         Application context.
 * @param[in] msg         Message to send
 * @param[in] msgLen      Length of the message to send
 * @param[out] result     Rpc operation result, freed by callers
 * @param[out] resultLen  Length of Rpc operation result
 *
 * @retval TRUE  RPC message send succeeded.
 * @retval FALSE RPC message send failed.
 *
 *****************************************************************************
 */

static Bool
SendRpcMessage(ToolsAppCtx *ctx,
               char const *msg,
               size_t msgLen,
               char **result,
               size_t *resultLen)
{
   Bool status;
   RpcChannelType rpcChannelType = RpcChannel_GetType(ctx->rpc);

   g_debug("%s: Current RPC channel type: %d\n", __FUNCTION__, rpcChannelType);

   if (rpcChannelType == RPCCHANNEL_TYPE_PRIV_VSOCK) {
      status = RpcChannel_Send(ctx->rpc, msg, msgLen, result, resultLen);
   } else {
      /*
       * After the vmsvc RPC channel falls back to backdoor, it could not
       * send through privileged guest RPC any more.
       */
      g_usleep(SERVICE_DISCOVERY_RPC_WAIT_TIME * 1000);
      status = RpcChannel_SendOneRawPriv(msg, msgLen, result, resultLen);

      /*
       * RpcChannel_SendOneRawPriv returns RPCCHANNEL_SEND_PERMISSION_DENIED
       * if the privileged vsocket can not be established.
       */
      if (!status && result != NULL &&
          strcmp(*result, RPCCHANNEL_SEND_PERMISSION_DENIED) == 0) {
         g_debug("%s: Retrying RPC send\n", __FUNCTION__);
         free(*result);
         g_usleep(SERVICE_DISCOVERY_RPC_WAIT_TIME * 1000);
         status = RpcChannel_SendOneRawPriv(msg, msgLen, result, resultLen);
      }
   }

   return status;
}

/*
 *****************************************************************************
 * SendData --
 *
 * Sends guest data to host-side gdp daemon.
 *
 * @param[in] ctx         The application context
 * @param[in] createTime  Data create time
 * @param[in] topic       Data topic
 * @param[in] data        Service data
 * @param[in] len         Service data length
 *
 * @retval TRUE  On success.
 * @retval FALSE Failed.
 *
 *****************************************************************************
 */

Bool
SendData(ToolsAppCtx *ctx,
         gint64 createTime,
         const char *topic,
         const char *data,
         const int len)
{
   GdpError gdpErr;
   Bool status = FALSE;
   Bool cacheData = VMTools_ConfigGetBoolean(
                       ctx->config,
                       CONFGROUPNAME_SERVICEDISCOVERY,
                       CONFNAME_SERVICEDISCOVERY_CACHEDATA,
                       SERVICE_DISCOVERY_CONF_DEFAULT_CACHEDATA);
   Bool requireSubs = VMTools_ConfigGetBoolean(
                         ctx->config,
                         CONFGROUPNAME_SERVICEDISCOVERY,
                         CONFNAME_SERVICEDISCOVERY_REQUIRESUBS,
                         SERVICE_DISCOVERY_CONF_DEFAULT_REQUIRESUBS);

   gdpErr = ToolsPluginSvcGdp_Publish(ctx,
                                      createTime,
                                      topic,
                                      NULL, /* token (optional) */
                                      NULL, /* category (optional) */
                                      data,
                                      len,
                                      cacheData,
                                      requireSubs);
   if (gdpErr != GDP_ERROR_SUCCESS) {
      g_info("%s: ToolsPluginSvcGdp_Publish error: %s\n",
             __FUNCTION__, gdpErrMsgs[gdpErr]);
      /* NOTE to SD maintainer: gdpErr == GDP_ERROR_NO_SUBSCRIBERS to be handled here when ready*/
      if (gdpErr == GDP_ERROR_STOP ||
          gdpErr == GDP_ERROR_UNREACH ||
          gdpErr == GDP_ERROR_TIMEOUT) {
         gSkipThisTask = TRUE;
      }
   } else {
      status = TRUE;
   }

   return status;
}

/*
 *****************************************************************************
 * fread_safe --
 *
 * A wrapper of C runtime library fread() with almost same signature except
 * the item size is always 1 byte. It ensures that when the returned number
 * of bytes is less than the input buffer size in bytes, an error has occurred
 * or the end of the file is encountered.
 *
 * @param [out] buf     Pointer to a block of memory with a size of at least
 *                      (size) bytes, converted to a void*.
 * @param [in] size     Size, in bytes, of each element to be read.
 * @param [in] stream   Pointer to a FILE object that specifies an input stream.
 * @param [out] eof     Indicates whether end of file is reached.
 *
 * @retval The total number of elements successfully read is returned.
 *
 *****************************************************************************
 */

static size_t
fread_safe(void *buf,
           size_t size,
           FILE *stream,
           Bool *eof)
{
   size_t readBytes = 0;

   while (readBytes < size) {
      size_t localReadBytes;

      /*
       * fread is a blocking call.
       */
      localReadBytes = fread((char *)buf + readBytes, 1,
                             size - readBytes, stream);

      if (ferror(stream)) {
         int error_code = 0;
         _get_errno(&error_code);
         g_info("%s: fread returned %"FMTSZ"u with errno=%d\n",
                __FUNCTION__, localReadBytes, error_code);
         break;
      }

      readBytes += localReadBytes;

      if (feof(stream)) {
         g_debug("%s: fread reached end of file\n",
                 __FUNCTION__);
         *eof = TRUE;
         break;
      }
   }

   return readBytes;
}

/*
 *****************************************************************************
 * WriteData --
 *
 * Sends key-value update request to the Namespace DB.
 *
 * @param[in] ctx       Application context.
 * @param[in] key       Key sent to the Namespace DB
 * @param[in] value     Service data sent to the Namespace DB
 * @param[in] len       Service data len
 *
 * @retval TRUE  Namespace DB write over RPC succeeded.
 * @retval FALSE Namespace DB write over RPC failed.
 *
 *****************************************************************************
 */

Bool
WriteData(ToolsAppCtx *ctx,
          const char *key,
          const char *data,
          const size_t len)
{
   Bool status = FALSE;
   DynBuf buf;
   gchar *timeStamp = NULL;

   if (data != NULL) {
      timeStamp = g_strdup_printf("%" G_GINT64_FORMAT, gLastWriteTime);
   }

   DynBuf_Init(&buf);

   /*
    * Format is:
    *
    * namespace-set-keys <namespace>\0<numOps>\0<op>\0<key>\0<value>\0<oldVal>
    *
    * We have just a single op, and want to always set the value, clobbering
    * anything already there.
    */
   if (!DynBuf_Append(&buf, NSDB_PRIV_SET_KEYS_CMD,
                      strlen(NSDB_PRIV_SET_KEYS_CMD)) ||
       !DynBuf_Append(&buf, " ", 1) ||
       !DynBuf_AppendString(&buf, SERVICE_DISCOVERY_NAMESPACE_DB_NAME) ||
       !DynBuf_AppendString(&buf, "1") || // numOps
       !DynBuf_AppendString(&buf, "0") || // op 0 == setAlways
       !DynBuf_AppendString(&buf, key)) {
      g_warning("%s: Could not construct buffer header\n", __FUNCTION__);
      goto out;
   }

   if (data != NULL) {
      if (!DynBuf_Append(&buf, timeStamp, strlen(timeStamp)) ||
          !DynBuf_Append(&buf, ",", 1) ||
          !DynBuf_Append(&buf, data, len) ||
          !DynBuf_Append(&buf, "", 1)) {
         g_warning("%s: Could not construct write buffer\n", __FUNCTION__);
         goto out;
      }
   } else {
      if (!DynBuf_Append(&buf, "", 1)) {
         g_warning("%s: Could not construct delete buffer\n", __FUNCTION__);
         goto out;
      }
   }

   if (!DynBuf_Append(&buf, "", 1)) {
      g_warning("%s: Could not construct buffer footer\n", __FUNCTION__);
      goto out;
   } else {
      char *result = NULL;
      size_t resultLen;

      status = SendRpcMessage(ctx, DynBuf_Get(&buf), DynBuf_GetSize(&buf),
                              &result, &resultLen);
      if (!status) {
         g_warning("%s: Failed to update %s, result: %s resultLen: %" FMTSZ
                   "u\n", __FUNCTION__, key, (result != NULL) ?
                   result : "(null)", resultLen);
      }

      if (result != NULL) {
         free(result);
      }
   }

out:
   DynBuf_Destroy(&buf);
   g_free(timeStamp);

   return status;
}


/*
 *****************************************************************************
 * ReadData --
 *
 * Reads value from Namespace DB by given key.
 *
 * @param[in] ctx             Application context.
 * @param[in] key             Key sent to the Namespace DB
 * @param[out] resultData     Data fetched from Namespace DB, freed by callers
 * @param[out] resultDataLen  Length of data fetched from Namespace DB
 *
 * @retval TRUE  Namespace DB read over RPC succeeded.
 * @retval FALSE Namespace DB read over RPC failed.
 *
 *****************************************************************************
 */

static Bool
ReadData(ToolsAppCtx *ctx,
         const char *key,
         char **resultData,
         size_t *resultDataLen)
{
   DynBuf buf;
   Bool status = FALSE;

   ASSERT(key);

   *resultData = NULL;
   *resultDataLen = 0;

   DynBuf_Init(&buf);

   /*
    * Format is
    *
    * namespace-get-values <namespace>\0<key>\0...
    *
    */
   if (!DynBuf_Append(&buf, NSDB_PRIV_GET_VALUES_CMD,
                      strlen(NSDB_PRIV_GET_VALUES_CMD)) ||
       !DynBuf_Append(&buf, " ", 1) ||
       !DynBuf_AppendString(&buf, SERVICE_DISCOVERY_NAMESPACE_DB_NAME) ||
       !DynBuf_AppendString(&buf, key)) {
      g_warning("%s: Could not construct request buffer\n", __FUNCTION__);
      goto done;
    }

   status = SendRpcMessage(ctx, DynBuf_Get(&buf), DynBuf_GetSize(&buf),
                           resultData, resultDataLen);
   if (!status) {
      g_debug("%s: Read over RPC failed, result: %s, resultDataLen: %" FMTSZ
              "u\n", __FUNCTION__, (*resultData != NULL) ?
              *resultData : "(null)", *resultDataLen);
   }
done:
   DynBuf_Destroy(&buf);
   return status;
}

/*
 *****************************************************************************
 * DepleteReadFromStream --
 *
 * Reads from stream and appends to the output dynamic buffer
 *
 * @param[in]  s            Stream
 * @param[out] out          Output buffer
 *
 *****************************************************************************
 */

void
DepleteReadFromStream(FILE *s,
                      DynBuf *out)
{
   for (;;) {
      size_t readBytes;
      char buf[SERVICE_DISCOVERY_VALUE_MAX_SIZE];

      readBytes = fread(buf, 1, sizeof(buf), s);

      g_debug("%s: readBytes = %"FMTSZ"u\n", __FUNCTION__, readBytes);

      if (readBytes > 0) {
         DynBuf_Append(out, buf, readBytes);
      }

      if (readBytes < sizeof(buf)) {
         break;
      }
   }
}


/*
 *****************************************************************************
 * DeleteData --
 *
 * Deletes keys/values from Namespace DB.
 *
 * @param[in] ctx       Application context.
 * @param[in] keys      Keys of entries to be deleted from the Namespace DB
 *
 * @retval TRUE  Namespace DB delete over RPC succeeded.
 * @retval FALSE Namespace DB delete over RPC failed or command buffer has not
 *               been constructed correctly.
 *
 *****************************************************************************
 */

static Bool
DeleteData(ToolsAppCtx *ctx,
           const GPtrArray* keys)
{
   Bool status = FALSE;
   DynBuf buf;
   int i;
   gchar *numKeys = g_strdup_printf("%d", keys->len);

   DynBuf_Init(&buf);

   /*
    * Format is:
    *
    * namespace-set-keys <namespace>\0<numOps>\0<op>\0<key>\0<value>\0<oldVal>
    *
    */
   if (!DynBuf_Append(&buf, NSDB_PRIV_SET_KEYS_CMD,
                      strlen(NSDB_PRIV_SET_KEYS_CMD)) ||
       !DynBuf_Append(&buf, " ", 1) ||
       !DynBuf_AppendString(&buf, SERVICE_DISCOVERY_NAMESPACE_DB_NAME) ||
       !DynBuf_AppendString(&buf, numKeys)) { // numOps
      g_warning("%s: Could not construct buffer header\n", __FUNCTION__);
      goto out;
   }
   for (i = 0; i < keys->len; ++i) {
      const char *key = (const char *) g_ptr_array_index(keys, i);
      g_debug("%s: Adding key %s to buffer\n", __FUNCTION__, key);
      if (!DynBuf_AppendString(&buf, "0") ||
          !DynBuf_AppendString(&buf, key) ||
          !DynBuf_Append(&buf, "", 1) ||
          !DynBuf_Append(&buf, "", 1)) {
         g_warning("%s: Could not construct delete buffer\n", __FUNCTION__);
         goto out;
      }
   }
   if (!DynBuf_Append(&buf, "", 1)) {
      g_warning("%s: Could not construct buffer footer\n", __FUNCTION__);
      goto out;
   } else {
      char *result = NULL;
      size_t resultLen;

      status = SendRpcMessage(ctx, DynBuf_Get(&buf), DynBuf_GetSize(&buf),
                              &result, &resultLen);
      if (!status) {
         g_warning("%s: Failed to delete keys, result: %s resultLen: %" FMTSZ
                   "u\n", __FUNCTION__, (result != NULL) ? result : "(null)",
                   resultLen);
      }

      free(result);
   }

out:
   DynBuf_Destroy(&buf);
   g_free(numKeys);
   return status;
}

/*
 *****************************************************************************
 * SendScriptOutput --
 *
 * Reads script child process stdout stream, sends output to
 * host-side gdp daemon and/or namespace DB.
 *
 * Stream output data are cut into chunks with chunk size of 16K for namespace
 * DB and 48K for gdp daemon. If there are multiple chunks of data, each chunk
 * is sent to gdp daemon/namespace db separately with its chunk number in the
 * topic.
 *
 * @param[in] ctx             The application context
 * @param[in] key             Script name
 * @param[in] childStdout     Stream to read child process stdout
 *
 * @retval TRUE  Successfully sent output.
 * @retval FALSE Otherwise.
 *
 *****************************************************************************
 */

Bool
SendScriptOutput(ToolsAppCtx *ctx,
                 const char *key,
                 FILE* childStdout)
{
   Bool status = TRUE;
   Bool gdp_status = TRUE;
   int i = 0;
   size_t totalReadBytes = 0;
   gint64 createTime = g_get_real_time();
   size_t ndbBufSize = SERVICE_DISCOVERY_VALUE_MAX_SIZE * sizeof(char);
   for (;;) {
      size_t readBytes;
      char buf[GDP_USER_DATA_LEN];
      Bool eof = FALSE;
      readBytes = fread_safe(buf, sizeof(buf), childStdout, &eof);

      totalReadBytes += readBytes;
      g_debug("%s: DB readBytes = %"FMTSZ"u\n", __FUNCTION__,
              readBytes);
      if (isGDPWriteReady && gdp_status && readBytes > 0) {
         g_debug("%s:%s Write to GDP readBytes = %"FMTSZ"u\n",
                 __FUNCTION__, key, readBytes);
         gchar* topic;

         if (eof || readBytes < sizeof(buf)) {
            topic = g_strdup_printf(SERVICE_DISCOVERY_TOPIC_PREFIX ".%s.%"FMTSZ
                                    "u.%"FMTSZ"u", key, cycle, totalReadBytes);
         } else {
            topic = g_strdup_printf(SERVICE_DISCOVERY_TOPIC_PREFIX ".%s.%"FMTSZ
                                    "u", key, cycle);
         }
         gdp_status = SendData(ctx, createTime, topic, buf, (int)readBytes);
         readBytesPerCycle += readBytes;
         g_free(topic);
      }

      if (isNDBWriteReady) {
         size_t ndbReadBytes = 0;
         size_t j;
         for (j = 0; j < readBytes; j += ndbReadBytes) {
            if (j + ndbBufSize > readBytes) {
               ndbReadBytes = readBytes - j;
            } else {
               ndbReadBytes = ndbBufSize;
            }
            if (status && ndbReadBytes > 0) {
               g_debug("%s:%s Write to Namespace DB readBytes = %"FMTSZ"u\n",
                       __FUNCTION__, key, ndbReadBytes);

               gchar* msg = g_strdup_printf("%s-%d", key, ++i);
               status = WriteData(ctx, msg, buf + j, ndbReadBytes);
               if (!status) {
                   g_warning("%s: Failed to store data\n", __FUNCTION__);
               }
               g_free(msg);
            }
         }
      }

      /*
       * Exit the loop only after childStdout is not readable any more.
       * Otherwise, the child process may be blocked in writing its stdout
       * and hang.
       */
      if (eof || readBytes < sizeof(buf)) {
         break;
      }

   }

   if (isNDBWriteReady && status) {
      gchar *chunkCount = g_strdup_printf("%d", i);
      status = WriteData(ctx, key, chunkCount, strlen(chunkCount));
      if (status) {
         g_debug("%s: Written key %s chunks %s\n", __FUNCTION__, key, chunkCount);
      }
      g_free(chunkCount);
   }

   return status && gdp_status;
}

/*
 *****************************************************************************
 * DeleteDataAndFree --
 *
 * Deletes the specified keys in Namespace DB and frees memory
 * for every key.
 *
 * @param[in] ctx           Application context.
 * @param[in/out] keys      Keys to be deleted.
 *
 *****************************************************************************
 */

static void
DeleteDataAndFree(ToolsAppCtx *ctx,
                  GPtrArray *keys) {
   int j;

   if (!DeleteData(ctx, keys)) {
      g_warning("%s: Failed to delete data\n", __FUNCTION__);
   }
   for (j = 0; j < keys->len; ++j) {
      g_free((gchar *) g_ptr_array_index(keys, j));
   }
   g_ptr_array_set_size(keys, 0);
}


/*
 *****************************************************************************
 * CleanupNamespaceDB --
 *
 * Deletes all the chunks written to the Namespace DB in previous cycle.
 *
 * @param[in] ctx       Application context.
 *
 *****************************************************************************
 */

static void
CleanupNamespaceDB(ToolsAppCtx *ctx) {
   int i;
   GPtrArray *keys = g_ptr_array_new();

   g_debug("%s: Performing cleanup of previous data\n", __FUNCTION__);

   ASSERT(gFullPaths);

   for (i = 0; i < gFullPaths->len; i++) {
      char *value = NULL;
      size_t len = 0;
      KeyNameValue tmp = g_array_index(gFullPaths, KeyNameValue, i);
      /*
       * Read count of chunks, ignore timestamp, iterate over chunks
       * and remove them.
       */
      if (ReadData(ctx, tmp.keyName, &value, &len) && len > 1) {
         char *token = NULL;
         g_debug("%s: Read %s from Namespace DB\n", __FUNCTION__, value);

         g_ptr_array_add(keys, g_strdup(tmp.keyName));
         if (keys->len >= SERVICE_DISCOVERY_DELETE_CHUNK_SIZE) {
            DeleteDataAndFree(ctx, keys);
         }

         if (NULL == strtok(value, ",")) {
            g_warning("%s: Malformed data for %s in Namespace DB",
                      __FUNCTION__, tmp.keyName);
            if (value) {
               free(value);
               value = NULL;
            }
            continue;
         }
         token = strtok(NULL, ",");
         if (token != NULL) {
            int count = (int) g_ascii_strtoll(token, NULL, 10);
            int j;

            for (j = 0; j < count; j++) {
               gchar *msg = g_strdup_printf("%s-%d", tmp.keyName, j + 1);
               g_ptr_array_add(keys, msg);
               if (keys->len >= SERVICE_DISCOVERY_DELETE_CHUNK_SIZE) {
                  DeleteDataAndFree(ctx, keys);
               }
            }
         } else {
            g_warning("%s: Chunk count has invalid value %s", __FUNCTION__,
                      value);
         }
      } else {
         g_warning("%s: Key %s not found in Namespace DB\n", __FUNCTION__,
                   tmp.keyName);
      }
      if (value) {
         free(value);
         value = NULL;
      }
   }
   if (keys->len >= 1) {
      DeleteDataAndFree(ctx, keys);
   }
   g_ptr_array_free(keys, TRUE);
}


/*
 *****************************************************************************
 * ServiceDiscoveryTask --
 *
 * Task to gather discovered services' data and write to Namespace DB.
 *
 * @param[in] ctx             Application context.
 * @param[in] data            Data pointer, not used.
 *
 *****************************************************************************
 */

static void
ServiceDiscoveryTask(ToolsAppCtx *ctx,
                     void *data)
{
   int i;
   Bool status = FALSE;
   Atomic_WriteBool(&gTaskSubmitted, TRUE);
   if (isGDPWriteReady) {
      gSkipThisTask = FALSE;
   }
   if (isNDBWriteReady) {
      gint64 previousWriteTime = gLastWriteTime;

      /*
       * We are going to write to Namespace DB, update gLastWriteTime
       */
      gLastWriteTime = GetGuestTimeInMillis();

      /*
       * Reset "ready" flag to stop readers until all data is written
       */
      status = WriteData(ctx, SERVICE_DISCOVERY_KEY_READY, "FALSE", 5);
      if (!status) {
         gLastWriteTime = previousWriteTime;
         g_warning("%s: Failed to reset %s flag", __FUNCTION__,
                   SERVICE_DISCOVERY_KEY_READY);
         if (!isGDPWriteReady) {
            Atomic_WriteBool(&gTaskSubmitted, FALSE);
            return;
         }
      }

      /*
       * Remove chunks written to DB in the previous iteration
       */
      CleanupNamespaceDB(ctx);
   }

   readBytesPerCycle = 0;
   cycle++;
   for (i = 0; i < gFullPaths->len; i++) {
      KeyNameValue tmp = g_array_index(gFullPaths, KeyNameValue, i);
      if (!ExecuteScript(ctx, tmp.keyName, tmp.val, scriptInstallDir)) {
         g_debug("%s: ExecuteScript failed for script %s\n",
                __FUNCTION__, tmp.val);
         if (isGDPWriteReady && gSkipThisTask && !isNDBWriteReady) {
            break;
         }
      }
   }

   if (isGDPWriteReady && !gSkipThisTask) {
      gchar* readyData = g_strdup_printf("%"FMTSZ"u", readBytesPerCycle);
      g_debug("%s: Sending ready flag with number of read bytes :%s\n",
             __FUNCTION__, readyData);
      gchar* topic = g_strdup_printf(SERVICE_DISCOVERY_TOPIC_PREFIX ".%s.%"
                                     FMTSZ"u", "ready", cycle);
      SendData(ctx, g_get_real_time(), topic, readyData, strlen(readyData));
      g_free(topic);
      g_free(readyData);
   }

   if (isNDBWriteReady) {
      /*
       * Update ready flag
       */
      status = WriteData(ctx, SERVICE_DISCOVERY_KEY_READY, "TRUE", 4);
      if (!status) {
         g_warning("%s: Failed to update ready flag", __FUNCTION__);
      }
   }

   Atomic_WriteBool(&gTaskSubmitted, FALSE);
}

/*
 *****************************************************************************
 * checkForWrite --
 *
 * Performs needed checks to decide if Data should be written to Namespace DB
 * or not.
 *
 * First check - checks if interval related information, stored in Namespace DB
 * under key "signal" and in format of "interval,timestamp" is outdated or not.
 *
 * Second check - checks if time greater than interval read from Namespace DB
 * has elapsed since the last write operation.
 *
 * @param[in] ctx           The application context.
 * @param[in] signalKey     Signal key to check the write readiness of
 *                          Namespace DB or gdp.
 *
 * @retval TRUE  Execute scripts and write service data to Namespace DB or gdp
 * @retval FALSE Omit this cycle wihtout any script running.
 *
 *****************************************************************************
 */

static Bool
checkForWrite(ToolsAppCtx *ctx, const char *signalKey)
{
   char *signal = NULL;
   size_t signalLen = 0;
   Bool result = FALSE;

   /*
    * Read signal from Namespace DB
    */
   if (!ReadData(ctx, signalKey, &signal, &signalLen)) {
      g_debug("%s: Failed to read necessary information from Namespace DB\n",
              __FUNCTION__);
   } else {
      if ((signal != NULL) && (strcmp(signal, "")) && signalLen > 0) {
         char *token1;
         char *token2;
         g_debug("%s: signal = %s last write time = %" G_GINT64_FORMAT "\n",
                 __FUNCTION__, signal, gLastWriteTime);
         /*
          * parse signal, it should be in "interval,timestamp" format
          */
         token1 = strtok(signal, ",");
         token2 = strtok(NULL, ",");
         if (token1 != NULL && token2 != NULL) {
            gint64 currentTime = GetGuestTimeInMillis();
            int clientInterval = (int) g_ascii_strtoll(token1, NULL, 10);
            gint64 clientTimestamp = g_ascii_strtoll(token2, NULL, 10);

            if (clientInterval == 0 || clientTimestamp == 0) {
               g_warning("%s: Wrong value of interval and timestamp",
                         __FUNCTION__);
            } else if ((currentTime - clientTimestamp) < (5 * clientInterval)) {
               if ((currentTime - gLastWriteTime +
                   SERVICE_DISCOVERY_WRITE_DELTA) >= clientInterval) {
                  result = TRUE;
               }
            } else {
               /*
               * Signal is outdated, reset the last write time
               */
               gLastWriteTime = 0;
            }

            g_debug("%s: result=%s client interval = %d "
                    "client timestamp =% " G_GINT64_FORMAT
                    " system time = %" G_GINT64_FORMAT
                    " previous write time = %" G_GINT64_FORMAT "\n",
                    __FUNCTION__, result ? "true" : "false", clientInterval,
                    clientTimestamp, currentTime, gLastWriteTime);
         } else {
            g_warning("%s: Wrong value of signal", __FUNCTION__);
         }
      } else {
         g_warning("%s: signal was NULL or empty", __FUNCTION__);
      }
   }

   if (signal) {
      free(signal);
   }

   return result;
}

/*
 *****************************************************************************
 * ServiceDiscoveryThread --
 *
 * Creates a new task thread that gathers discovered services' data and
 * publishes the data to either Namespace DB or host-side gdp daemon.
 *
 * @param[in]  data     The application context.
 *
 * @return TRUE to indicate that the timer should be rescheduled.
 *
 *****************************************************************************
 */

static Bool
ServiceDiscoveryThread(gpointer data)
{
   ToolsAppCtx *ctx = data;
   #if defined(VMX86_DEBUG)
   if (isGDPDebug) {
      isGDPWriteReady = TRUE;
      isNDBWriteReady = FALSE;
   } else {
      isGDPWriteReady = checkForWrite(ctx, SERVICE_DISCOVERY_KEY_GDP_SIGNAL);
      isNDBWriteReady = checkForWrite(ctx, SERVICE_DISCOVERY_KEY_SIGNAL);
   }
   #else
   isGDPWriteReady = checkForWrite(ctx, SERVICE_DISCOVERY_KEY_GDP_SIGNAL);
   isNDBWriteReady = checkForWrite(ctx, SERVICE_DISCOVERY_KEY_SIGNAL);
   #endif

   /*
    * First check for taskSubmitted, if it is true automatically omit this
    * cycle even without checking for write to avoid resetting last write
    * time.
    */
   if (Atomic_ReadBool(&gTaskSubmitted)) {
      g_debug("%s: Previously submitted task is not completed\n", __FUNCTION__);
   } else if (!isNDBWriteReady && !isGDPWriteReady) {
      g_debug("%s: Neither Namespace DB nor GDP is ready for writing\n",
              __FUNCTION__);
   } else {
      g_debug("%s: Submitting task to write\n", __FUNCTION__);
      if (!ToolsCorePool_SubmitTask(ctx, ServiceDiscoveryTask, NULL, NULL)) {
         g_warning("%s: failed to start information gather thread\n",
                   __FUNCTION__);
      }
   }

   return TRUE;
}


/*
 *****************************************************************************
 * TweakDiscoveryLoop --
 *
 * @brief Start service discovery poll loop.
 *
 * @param[in] ctx  The app context.
 *
 *****************************************************************************
 */

static void
TweakDiscoveryLoop(ToolsAppCtx *ctx)
{
   if (gServiceDiscoveryTimeoutSource == NULL) {
      gint pollInterval = SERVICE_DISCOVERY_POLL_INTERVAL;
      #if defined(VMX86_DEBUG)
      isGDPDebug =
               VMTools_ConfigGetBoolean(ctx->config,
                                        CONFGROUPNAME_SERVICEDISCOVERY,
                                        CONFNAME_SERVICEDISCOVERY_GDP_DEBUG,
                                        FALSE);
      if (isGDPDebug) {
         pollInterval = GetGDPPollInterval(ctx);
         g_info("%s: GDP Debug is enabled with %d ms polling interval\n",
                __FUNCTION__, pollInterval);
      }
      #endif
      gServiceDiscoveryTimeoutSource =
                          g_timeout_source_new(pollInterval);
      VMTOOLSAPP_ATTACH_SOURCE(ctx, gServiceDiscoveryTimeoutSource,
                               ServiceDiscoveryThread, ctx, NULL);
      g_source_unref(gServiceDiscoveryTimeoutSource);
   }
}


/*
 ******************************************************************************
 * ServiceDiscoveryServerConfReload --
 *
 * @brief Reconfigures the poll loop interval upon config file reload.
 *
 * @param[in]  src     Unused.
 * @param[in]  ctx     The application context.
 * @param[in]  data    Unused.
 *
 ******************************************************************************
 */

static void
ServiceDiscoveryServerConfReload(gpointer src,
                                 ToolsAppCtx *ctx,
                                 gpointer data)
{
   gboolean disabled =
      VMTools_ConfigGetBoolean(ctx->config,
                               CONFGROUPNAME_SERVICEDISCOVERY,
                               CONFNAME_SERVICEDISCOVERY_DISABLED,
                               SERVICE_DISCOVERY_CONF_DEFAULT_DISABLED_VALUE);
   if (!disabled) {
      g_info("%s: Service discovery loop started\n", __FUNCTION__);
      TweakDiscoveryLoop(ctx);
   } else if (gServiceDiscoveryTimeoutSource != NULL) {
      gLastWriteTime = 0;
      g_source_destroy(gServiceDiscoveryTimeoutSource);
      gServiceDiscoveryTimeoutSource = NULL;
      g_info("%s: Service discovery loop disabled\n", __FUNCTION__);
   }
}


/*
 *****************************************************************************
 * ServiceDiscoveryServerShutdown --
 *
 * Cleanup internal data on shutdown.
 *
 * @param[in]  src     The source object.
 * @param[in]  ctx     Unused.
 * @param[in]  data    Unused.
 *
 *****************************************************************************
 */

static void
ServiceDiscoveryServerShutdown(gpointer src,
                               ToolsAppCtx *ctx,
                               gpointer data)
{
   if (gServiceDiscoveryTimeoutSource != NULL) {
      g_source_destroy(gServiceDiscoveryTimeoutSource);
      gServiceDiscoveryTimeoutSource = NULL;
   }

   g_free(scriptInstallDir);
   scriptInstallDir = NULL;

   if (gFullPaths != NULL) {
      int i = 0;
      guint len = gFullPaths->len;
      for (i = 0; i < len; ++i) {
         g_free(g_array_index(gFullPaths, KeyNameValue, i).keyName);
         g_free(g_array_index(gFullPaths, KeyNameValue, i).val);
      }
      g_array_free(gFullPaths, TRUE);
   }
}

/*
 *****************************************************************************
 * ConstructScriptPaths --
 *
 * Construct final paths of the scripts that will be used for execution.
 *
 *****************************************************************************
 */

static void
ConstructScriptPaths(void)
{
   int i;
#if !defined(OPEN_VM_TOOLS)
   gchar *toolsInstallDir;
#endif

   if (gFullPaths != NULL) {
      return;
   }

   gFullPaths = g_array_sized_new(FALSE, TRUE, sizeof(KeyNameValue),
                                  ARRAYSIZE(gKeyScripts));
   if (scriptInstallDir == NULL) {
#if defined(OPEN_VM_TOOLS)
      scriptInstallDir = Util_SafeStrdup(VMTOOLS_SERVICE_DISCOVERY_SCRIPTS);
#else
      toolsInstallDir = GuestApp_GetInstallPath();
      scriptInstallDir = g_strdup_printf("%s%s%s%s%s", toolsInstallDir, DIRSEPS,
                                      "serviceDiscovery", DIRSEPS, "scripts");
      g_free(toolsInstallDir);
#endif
   }
   for (i = 0; i < ARRAYSIZE(gKeyScripts); ++i) {
      KeyNameValue tmp;
      tmp.keyName = g_strdup_printf("%s", gKeyScripts[i].keyName);
#if defined(_WIN32)
      tmp.val = ConstructPWSScriptCommand(gKeyScripts[i].val);
#else
      tmp.val = g_strdup_printf("%s%s%s", scriptInstallDir, DIRSEPS, gKeyScripts[i].val);
#endif
      g_array_insert_val(gFullPaths, i, tmp);
   }
}


/*
 *****************************************************************************
 * ToolsOnLoad --
 *
 * Plugin entry point. Initializes internal plugin state.
 *
 * @param[in]  ctx   The app context.
 *
 * @return The registration data.
 *
 *****************************************************************************
 */

TOOLS_MODULE_EXPORT ToolsPluginData *
ToolsOnLoad(ToolsAppCtx *ctx)
{
   static ToolsPluginData regData = {
      "serviceDiscovery",
      NULL,
      NULL
   };

   uint32 vmxVersion = 0;
   uint32 vmxType = VMX_TYPE_UNSET;

   /*
    * Return NULL to disable the plugin if not running in a VMware VM.
    */
   if (!ctx->isVMware) {
      g_info("%s: Not running in a VMware VM.\n", __FUNCTION__);
      return NULL;
   }

   /*
    * Return NULL to disable the plugin if VM is not running on ESX host.
    */
   if (!VmCheck_GetVersion(&vmxVersion, &vmxType) ||
       vmxType != VMX_TYPE_SCALABLE_SERVER) {
      g_info("%s, VM is not running on ESX host.\n", __FUNCTION__);
      return NULL;
   }

   /*
    * Return NULL to disable the plugin if not running in vmsvc daemon.
    */
   if (!TOOLS_IS_MAIN_SERVICE(ctx)) {
      g_info("%s: Not running in vmsvc daemon: container name='%s'.\n",
             __FUNCTION__, ctx->name);
      return NULL;
   }
   if (ctx->rpc != NULL) {
      ToolsPluginSignalCb sigs[] = {
         { TOOLS_CORE_SIG_SHUTDOWN, ServiceDiscoveryServerShutdown, NULL },
         { TOOLS_CORE_SIG_CONF_RELOAD, ServiceDiscoveryServerConfReload, NULL }
      };
      ToolsAppReg regs[] = {
         { TOOLS_APP_SIGNALS,
           VMTools_WrapArray(sigs, sizeof *sigs, ARRAYSIZE(sigs))
         }
      };
      gboolean disabled;

      regData.regs = VMTools_WrapArray(regs,
                                       sizeof *regs,
                                       ARRAYSIZE(regs));
      /*
       * Append scripts execution command line
       */
      ConstructScriptPaths();

      disabled =
         VMTools_ConfigGetBoolean(ctx->config,
                                  CONFGROUPNAME_SERVICEDISCOVERY,
                                  CONFNAME_SERVICEDISCOVERY_DISABLED,
                                  SERVICE_DISCOVERY_CONF_DEFAULT_DISABLED_VALUE);
      if (!disabled) {
         TweakDiscoveryLoop(ctx);
      }

      return &regData;
   }

   return NULL;
}
