src/dird/ua_purge.c

/*
   Bacula(R) - The Network Backup Solution

   Copyright (C) 2000-2020 Kern Sibbald

   The original author of Bacula is Kern Sibbald, with contributions
   from many others, a complete list can be found in the file AUTHORS.

   You may use this file and others of this release according to the
   license defined in the LICENSE file, which includes the Affero General
   Public License, v3.0 ("AGPLv3") and some additional permissions and
   terms pursuant to its AGPLv3 Section 7.

   This notice must be preserved when any source code is
   conveyed and/or propagated.

   Bacula(R) is a registered trademark of Kern Sibbald.
*/
/*
 *
 *   Bacula Director -- User Agent Database Purge Command
 *
 *      Purges Files from specific JobIds
 * or
 *      Purges Jobs from Volumes
 *
 *     Kern Sibbald, February MMII
 *
 */

#include "bacula.h"
#include "dird.h"

/* Forward referenced functions */
static int purge_files_from_client(UAContext *ua, CLIENT *client);
static int purge_jobs_from_client(UAContext *ua, CLIENT *client);
int truncate_cmd(UAContext *ua, const char *cmd);

static const char *select_jobsfiles_from_client =
   "SELECT JobId FROM Job "
   "WHERE ClientId=%s "
   "AND PurgedFiles=0";

static const char *select_jobs_from_client =
   "SELECT JobId, PurgedFiles FROM Job "
   "WHERE ClientId=%s";

/*
 *   Purge records from database
 *
 *     Purge Files (from) [Job|JobId|Client|Volume]
 *     Purge Jobs  (from) [Client|Volume]
 *     Purge Volumes
 *
 *  N.B. Not all above is implemented yet.
 */
int purge_cmd(UAContext *ua, const char *cmd)
{
   int i;
   CLIENT *client;
   MEDIA_DBR mr;
   JOB_DBR  jr;
   memset(&jr, 0, sizeof(jr));

   static const char *keywords[] = {
      NT_("files"),
      NT_("jobs"),
      NT_("volume"),
      NULL};

   static const char *files_keywords[] = {
      NT_("Job"),
      NT_("JobId"),
      NT_("Client"),
      NT_("Volume"),
      NULL};

   static const char *jobs_keywords[] = {
      NT_("Client"),
      NT_("Volume"),
      NULL};

   /* Special case for the "Action On Purge", this option is working only on
    * Purged volume, so no jobs or files will be purged.
    * We are skipping this message if "purge volume action=xxx"
    */
   if (!(find_arg(ua, "volume") >= 0 && find_arg(ua, "action") >= 0)) {
      ua->warning_msg(_(
        "\nThis command can be DANGEROUS!!!\n\n"
        "It purges (deletes) all Files from a Job,\n"
        "JobId, Client or Volume; or it purges (deletes)\n"
        "all Jobs from a Client or Volume without regard\n"
        "to retention periods. Normally you should use the\n"
        "PRUNE command, which respects retention periods.\n"));
   }

   if (!open_new_client_db(ua)) {
      return 1;
   }
   switch (find_arg_keyword(ua, keywords)) {
   /* Files */
   case 0:
      switch(find_arg_keyword(ua, files_keywords)) {
      case 0:                         /* Job */
      case 1:                         /* JobId */
         if (get_job_dbr(ua, &jr)) {
            char jobid[50];
            edit_int64(jr.JobId, jobid);
            purge_files_from_jobs(ua, jobid);
         }
         return 1;
      case 2:                         /* client */
         /* We restrict the client list to ClientAcl, maybe something to change later */
         client = get_client_resource(ua, JT_SYSTEM);
         if (client) {
            purge_files_from_client(ua, client);
         }
         return 1;
      case 3:                         /* Volume */
         if (select_media_dbr(ua, &mr)) {
            purge_files_from_volume(ua, &mr);
         }
         return 1;
      }
   /* Jobs */
   case 1:
      switch(find_arg_keyword(ua, jobs_keywords)) {
      case 0:                         /* client */
         /* We restrict the client list to ClientAcl, maybe something to change later */
         client = get_client_resource(ua, JT_SYSTEM);
         if (client) {
            purge_jobs_from_client(ua, client);
         }
         return 1;
      case 1:                         /* Volume */
         if (select_media_dbr(ua, &mr)) {
            purge_jobs_from_volume(ua, &mr, /*force*/true);
         }
         return 1;
      }
   /* Volume */
   case 2:
      /* Perform ActionOnPurge (action=truncate) */
      if (find_arg(ua, "action") >= 0) {
         return truncate_cmd(ua, ua->cmd);
      }

      while ((i=find_arg(ua, NT_("volume"))) >= 0) {
         if (select_media_dbr(ua, &mr)) {
            purge_jobs_from_volume(ua, &mr, /*force*/true);
         }
         *ua->argk[i] = 0;            /* zap keyword already seen */
         ua->send_msg("\n");
      }
      return 1;
   default:
      break;
   }
   switch (do_keyword_prompt(ua, _("Choose item to purge"), keywords)) {
   case 0:                            /* files */
      /* We restrict the client list to ClientAcl, maybe something to change later */
      client = get_client_resource(ua, JT_SYSTEM);
      if (client) {
         purge_files_from_client(ua, client);
      }
      break;
   case 1:                            /* jobs */
      /* We restrict the client list to ClientAcl, maybe something to change later */
      client = get_client_resource(ua, JT_SYSTEM);
      if (client) {
         purge_jobs_from_client(ua, client);
      }
      break;
   case 2:                            /* Volume */
      if (select_media_dbr(ua, &mr)) {
         purge_jobs_from_volume(ua, &mr, /*force*/true);
      }
      break;
   }
   return 1;
}

/*
 * Purge File records from the database. For any Job which
 * is older than the retention period, we unconditionally delete
 * all File records for that Job.  This is simple enough that no
 * temporary tables are needed. We simply make an in memory list of
 * the JobIds meeting the prune conditions, then delete all File records
 * pointing to each of those JobIds.
 */
static int purge_files_from_client(UAContext *ua, CLIENT *client)
{
   struct del_ctx del;
   POOL_MEM query(PM_MESSAGE);
   CLIENT_DBR cr;
   char ed1[50];

   memset(&cr, 0, sizeof(cr));
   bstrncpy(cr.Name, client->name(), sizeof(cr.Name));
   if (!db_create_client_record(ua->jcr, ua->db, &cr)) {
      return 0;
   }

   memset(&del, 0, sizeof(del));
   del.max_ids = 1000;
   del.JobId = (JobId_t *)malloc(sizeof(JobId_t) * del.max_ids);

   /* Keep track of this important event */
   ua->send_events("DC0001", EVENTS_TYPE_COMMAND, "purge files client=%s", cr.Name);
   ua->info_msg(_("Begin purging files for Client \"%s\"\n"), cr.Name);

   Mmsg(query, select_jobsfiles_from_client, edit_int64(cr.ClientId, ed1));
   Dmsg1(050, "select sql=%s\n", query.c_str());
   db_sql_query(ua->db, query.c_str(), file_delete_handler, (void *)&del);

   purge_files_from_job_list(ua, del);

   if (del.num_del == 0) {
      ua->warning_msg(_("No Files found for client %s to purge from %s catalog.\n"),
         client->name(), client->catalog->name());
   } else {
      ua->info_msg(_("Files for %d Jobs for client \"%s\" purged from %s catalog.\n"), del.num_del,
         client->name(), client->catalog->name());
   }

   if (del.JobId) {
      free(del.JobId);
   }
   return 1;
}


/*
 * Purge Job records from the database. For any Job which
 * is older than the retention period, we unconditionally delete
 * it and all File records for that Job.  This is simple enough that no
 * temporary tables are needed. We simply make an in memory list of
 * the JobIds then delete the Job, Files, and JobMedia records in that list.
 */
static int purge_jobs_from_client(UAContext *ua, CLIENT *client)
{
   struct del_ctx del;
   POOL_MEM query(PM_MESSAGE);
   CLIENT_DBR cr;
   char ed1[50];

   memset(&cr, 0, sizeof(cr));

   bstrncpy(cr.Name, client->name(), sizeof(cr.Name));
   if (!db_create_client_record(ua->jcr, ua->db, &cr)) {
      return 0;
   }

   memset(&del, 0, sizeof(del));
   del.max_ids = 1000;
   del.JobId = (JobId_t *)malloc(sizeof(JobId_t) * del.max_ids);
   del.PurgedFiles = (char *)malloc(del.max_ids);

   ua->info_msg(_("Begin purging jobs from Client \"%s\"\n"), cr.Name);

   Mmsg(query, select_jobs_from_client, edit_int64(cr.ClientId, ed1));
   Dmsg1(150, "select sql=%s\n", query.c_str());
   db_sql_query(ua->db, query.c_str(), job_delete_handler, (void *)&del);

   purge_job_list_from_catalog(ua, del);

   if (del.num_del == 0) {
      ua->warning_msg(_("No Jobs found for client %s to purge from %s catalog.\n"),
         client->name(), client->catalog->name());
   } else {
      ua->info_msg(_("%d Jobs for client %s purged from %s catalog.\n"), del.num_del,
         client->name(), client->catalog->name());
   }

   if (del.JobId) {
      free(del.JobId);
   }
   if (del.PurgedFiles) {
      free(del.PurgedFiles);
   }
   return 1;
}


/*
 * Remove File records from a list of JobIds
 */
void purge_files_from_jobs(UAContext *ua, char *jobs)
{
   POOL_MEM query(PM_MESSAGE);

   Mmsg(query, "DELETE FROM File WHERE JobId IN (%s)", jobs);
   db_sql_query(ua->db, query.c_str(), NULL, (void *)NULL);
   Dmsg1(050, "Delete File sql=%s\n", query.c_str());

   Mmsg(query, "DELETE FROM FileMedia WHERE JobId IN (%s)", jobs);
   db_sql_query(ua->db, query.c_str(), NULL, (void *)NULL);
   Dmsg1(050, "Delete FileMedia sql=%s\n", query.c_str());

   Mmsg(query, "DELETE FROM BaseFiles WHERE JobId IN (%s)", jobs);
   db_sql_query(ua->db, query.c_str(), NULL, (void *)NULL);
   Dmsg1(050, "Delete BaseFiles sql=%s\n", query.c_str());

   Mmsg(query, "DELETE FROM PathVisibility WHERE JobId IN (%s)", jobs);
   db_sql_query(ua->db, query.c_str(), NULL, (void *)NULL);
   Dmsg1(050, "Delete PathVisibility sql=%s\n", query.c_str());

   /*
    * Now mark Job as having files purged. This is necessary to
    * avoid having too many Jobs to process in future prunings. If
    * we don't do this, the number of JobId's in our in memory list
    * could grow very large.
    */
   Mmsg(query, "UPDATE Job SET PurgedFiles=1 WHERE JobId IN (%s)", jobs);
   db_sql_query(ua->db, query.c_str(), NULL, (void *)NULL);
   Dmsg1(050, "Mark purged sql=%s\n", query.c_str());
}

/*
 * Delete jobs (all records) from the catalog in groups of 1000
 *  at a time.
 */
void purge_job_list_from_catalog(UAContext *ua, del_ctx &del)
{
   POOL_MEM jobids(PM_MESSAGE);
   char ed1[50];

   exclude_running_jobs_from_list(&del);

   for (int i=0; del.num_ids; ) {
      Dmsg1(150, "num_ids=%d\n", del.num_ids);
      pm_strcat(jobids, "");
      for (int j=0; j<1000 && del.num_ids>0; j++) {
         del.num_ids--;
         if (del.JobId[i] == 0 || ua->jcr->JobId == del.JobId[i]) {
            Dmsg2(150, "skip JobId[%d]=%d\n", i, (int)del.JobId[i]);
            i++;
            continue;
         }
         if (*jobids.c_str() != 0) {
            pm_strcat(jobids, ",");
         }
         pm_strcat(jobids, edit_int64(del.JobId[i++], ed1));
         Dmsg1(150, "Add id=%s\n", ed1);
         del.num_del++;
      }
      Dmsg1(150, "num_ids=%d\n", del.num_ids);
      purge_jobs_from_catalog(ua, jobids.c_str());
   }
}

/*
 * Delete files from a list of jobs in groups of 1000
 *  at a time.
 */
void purge_files_from_job_list(UAContext *ua, del_ctx &del)
{
   POOL_MEM jobids(PM_MESSAGE);
   char ed1[50];
   /*
    * OK, now we have the list of JobId's to be pruned, send them
    *   off to be deleted batched 1000 at a time.
    */
   for (int i=0; del.num_ids; ) {
      pm_strcat(jobids, "");
      for (int j=0; j<1000 && del.num_ids>0; j++) {
         del.num_ids--;
         if (del.JobId[i] == 0 || ua->jcr->JobId == del.JobId[i]) {
            Dmsg2(150, "skip JobId[%d]=%d\n", i, (int)del.JobId[i]);
            i++;
            continue;
         }
         if (*jobids.c_str() != 0) {
            pm_strcat(jobids, ",");
         }
         pm_strcat(jobids, edit_int64(del.JobId[i++], ed1));
         Dmsg1(150, "Add id=%s\n", ed1);
         del.num_del++;
      }
      purge_files_from_jobs(ua, jobids.c_str());
   }
}

/*
 * Change the type of the next copy job to backup.
 * We need to upgrade the next copy of a normal job,
 * and also upgrade the next copy when the normal job
 * already have been purged.
 *
 *   JobId: 1   PriorJobId: 0    (original)
 *   JobId: 2   PriorJobId: 1    (first copy)
 *   JobId: 3   PriorJobId: 1    (second copy)
 *
 *   JobId: 2   PriorJobId: 1    (first copy, now regular backup)
 *   JobId: 3   PriorJobId: 1    (second copy)
 *
 *  => Search through PriorJobId in jobid and
 *                    PriorJobId in PriorJobId (jobid)
 */
void upgrade_copies(UAContext *ua, char *jobs)
{
   POOL_MEM query(PM_MESSAGE);
   int dbtype = ua->db->bdb_get_type_index();

   db_lock(ua->db);

   Mmsg(query, uap_upgrade_copies_oldest_job[dbtype], JT_JOB_COPY, jobs, jobs);
   db_sql_query(ua->db, query.c_str(), NULL, (void *)NULL);
   Dmsg1(050, "Upgrade copies Log sql=%s\n", query.c_str());

   /* Now upgrade first copy to Backup */
   Mmsg(query, "UPDATE Job SET Type='B' "      /* JT_JOB_COPY => JT_BACKUP  */
                "WHERE JobId IN ( SELECT JobId FROM cpy_tmp )");

   db_sql_query(ua->db, query.c_str(), NULL, (void *)NULL);

   Mmsg(query, "DROP TABLE cpy_tmp");
   db_sql_query(ua->db, query.c_str(), NULL, (void *)NULL);

   db_unlock(ua->db);
}

/*
 * Remove all records from catalog for a list of JobIds
 */
void purge_jobs_from_catalog(UAContext *ua, char *jobs)
{
   POOL_MEM query(PM_MESSAGE);
   /* Keep track of this important event */
   ua->send_events("DC0002", EVENTS_TYPE_COMMAND, "purge jobid=%s", jobs);

   /* Delete (or purge) records associated with the job */
   purge_files_from_jobs(ua, jobs);

   Mmsg(query, "DELETE FROM JobMedia WHERE JobId IN (%s)", jobs);
   db_sql_query(ua->db, query.c_str(), NULL, (void *)NULL);
   Dmsg1(050, "Delete JobMedia sql=%s\n", query.c_str());

   Mmsg(query, "DELETE FROM FileMedia WHERE JobId IN (%s)", jobs);
   db_sql_query(ua->db, query.c_str(), NULL, (void *)NULL);
   Dmsg1(050, "Delete JobMedia sql=%s\n", query.c_str());

   Mmsg(query, "DELETE FROM Log WHERE JobId IN (%s)", jobs);
   db_sql_query(ua->db, query.c_str(), NULL, (void *)NULL);
   Dmsg1(050, "Delete Log sql=%s\n", query.c_str());

   Mmsg(query, "DELETE FROM RestoreObject WHERE JobId IN (%s)", jobs);
   db_sql_query(ua->db, query.c_str(), NULL, (void *)NULL);
   Dmsg1(050, "Delete RestoreObject sql=%s\n", query.c_str());

   /* The JobId of the Snapshot record is no longer usable
    * TODO: Migth want to use a copy for the jobid?
    */
   Mmsg(query, "UPDATE Snapshot SET JobId=0 WHERE JobId IN (%s)", jobs);
   db_sql_query(ua->db, query.c_str(), NULL, (void *)NULL);

   upgrade_copies(ua, jobs);
   /* Now remove the Job record itself */
   Mmsg(query, "DELETE FROM Job WHERE JobId IN (%s)", jobs);
   db_sql_query(ua->db, query.c_str(), NULL, (void *)NULL);

   Dmsg1(050, "Delete Job sql=%s\n", query.c_str());
}

void purge_files_from_volume(UAContext *ua, MEDIA_DBR *mr )
{} /* ***FIXME*** implement */

/*
 * Returns: 1 if Volume purged
 *          0 if Volume not purged
 */
bool purge_jobs_from_volume(UAContext *ua, MEDIA_DBR *mr, bool force)
{
   POOL_MEM query(PM_MESSAGE);
   db_list_ctx lst_all, lst;
   char *jobids=NULL;
   int i;
   bool purged = false;
   bool stat;

   stat = strcmp(mr->VolStatus, "Append") == 0 ||
          strcmp(mr->VolStatus, "Full")   == 0 ||
          strcmp(mr->VolStatus, "Used")   == 0 ||
          strcmp(mr->VolStatus, "Error")  == 0;
   if (!stat) {
      ua->error_msg(_("\nVolume \"%s\" has VolStatus \"%s\" and cannot be purged.\n"
                     "The VolStatus must be: Append, Full, Used, or Error to be purged.\n"),
                     mr->VolumeName, mr->VolStatus);
      return 0;
   }

   /*
    * Check if he wants to purge a single jobid
    */
   i = find_arg_with_value(ua, "jobid");
   if (i >= 0 && is_a_number_list(ua->argv[i])) {
      jobids = ua->argv[i];

   } else {
      POOL_MEM query;
      /*
       * Purge ALL JobIds
       */
      if (!db_get_volume_jobids(ua->jcr, ua->db, mr, &lst_all)) {
         ua->error_msg("%s", db_strerror(ua->db));
         Dmsg0(050, "Count failed\n");
         goto bail_out;
      }

      if (lst_all.count > 0) {
         Mmsg(query, "SELECT JobId FROM Job WHERE JobId IN (%s) AND JobStatus NOT IN ('R', 'C')",
              lst_all.list);
         if (!db_sql_query(ua->db, query.c_str(), db_list_handler, &lst)) {
            ua->error_msg("%s", db_strerror(ua->db));
            goto bail_out;
         }
      }
      jobids = lst.list;
   }

   if (*jobids) {
      /* Keep track of this important event */
      ua->send_events("DC0003", EVENTS_TYPE_COMMAND, "purge volume=%s", mr->VolumeName);

      purge_jobs_from_catalog(ua, jobids);
      ua->info_msg(_("%d Job%s on Volume \"%s\" purged from catalog.\n"),
                   lst.count, lst.count<=1?"":"s", mr->VolumeName);
   }
   purged = is_volume_purged(ua, mr, force);

bail_out:
   return purged;
}

/*
 * This routine will check the JobMedia records to see if the
 *   Volume has been purged. If so, it marks it as such and
 *
 * Returns: true if volume purged
 *          false if not
 *
 * Note, we normally will not purge a volume that has Firstor LastWritten
 *   zero, because it means the volume is most likely being written
 *   however, if the user manually purges using the purge command in
 *   the console, he has been warned, and we go ahead and purge
 *   the volume anyway, if possible).
 */
bool is_volume_purged(UAContext *ua, MEDIA_DBR *mr, bool force)
{
   POOL_MEM query(PM_MESSAGE);
   struct s_count_ctx cnt;
   bool purged = false;
   char ed1[50];

   if (!force && (mr->FirstWritten == 0 || mr->LastWritten == 0)) {
      goto bail_out;               /* not written cannot purge */
   }

   if (strcmp(mr->VolStatus, "Purged") == 0) {
      Dmsg1(100, "Volume=%s already purged.\n", mr->VolumeName);
      purged = true;
      goto bail_out;
   }

   /* If purged, mark it so */
   cnt.count = 0;
   Mmsg(query, "SELECT 1 FROM JobMedia WHERE MediaId=%s LIMIT 1",
        edit_int64(mr->MediaId, ed1));
   if (!db_sql_query(ua->db, query.c_str(), del_count_handler, (void *)&cnt)) {
      ua->error_msg("%s", db_strerror(ua->db));
      Dmsg0(050, "Count failed\n");
      goto bail_out;
   }

   if (cnt.count == 0) {
      ua->warning_msg(_("There are no more Jobs associated with Volume \"%s\". Marking it purged.\n"),
         mr->VolumeName);
      Dmsg1(100, "There are no more Jobs associated with Volume \"%s\". Marking it purged.\n",
         mr->VolumeName);
      if (!(purged = mark_media_purged(ua, mr))) {
         ua->error_msg("%s", db_strerror(ua->db));
      }
   }
bail_out:
   return purged;
}

/*
 * Called here to send the appropriate commands to the SD
 *  to do truncate on purge.
 */
static void truncate_volume(UAContext *ua, MEDIA_DBR *mr,
                            char *pool, char *storage,
                            int drive, BSOCK *sd)
{
   bool ok = false;
   uint64_t VolBytes = 0;
   uint64_t VolABytes = 0;
   uint32_t VolType = 0;

   if (!mr->Recycle) {
      return;
   }

   /* Do it only if action on purge = truncate is set */
   if (!(mr->ActionOnPurge & ON_PURGE_TRUNCATE)) {
      ua->error_msg(_("\nThe option \"Action On Purge = Truncate\" was not defined in the Pool resource.\n"
                      "Truncate not allowed on Volume \"%s\"\n"), mr->VolumeName);
      return;
   }

   /*
    * Send the command to truncate the volume after purge. If this feature
    * is disabled for the specific device, this will be a no-op.
    */

   /* Protect us from spaces */
   bash_spaces(mr->VolumeName);
   bash_spaces(mr->MediaType);
   bash_spaces(pool);
   bash_spaces(storage);

   /* Do it by relabeling the Volume, which truncates it */
   sd->fsend("relabel %s OldName=%s NewName=%s PoolName=%s "
             "MediaType=%s Slot=%d drive=%d\n",
             storage,
             mr->VolumeName, mr->VolumeName,
             pool, mr->MediaType, mr->Slot, drive);

   unbash_spaces(mr->VolumeName);
   unbash_spaces(mr->MediaType);
   unbash_spaces(pool);
   unbash_spaces(storage);

   /* Check for valid response. With cloud volumes, the upload of the part.1 can
    * generate a dir_update_volume_info() message that is handled by bget_dirmsg()
    */
   while (bget_dirmsg(sd) >= 0) {
      ua->send_msg("%s", sd->msg);
      if (sscanf(sd->msg, "3000 OK label. VolBytes=%llu VolABytes=%lld VolType=%d ",
                 &VolBytes, &VolABytes, &VolType) == 3) {

         ok = true;
         /* Clean up a few things in the media record */
         mr->VolBytes = VolBytes;
         mr->VolABytes = VolABytes;
         mr->VolType = VolType;
         mr->VolFiles = 0;
         mr->VolParts = 1;
         mr->VolCloudParts = 0;
         mr->LastPartBytes = VolBytes;
         mr->VolJobs = 0;
         mr->VolBlocks = 1;
         mr->VolHoleBytes = 0;
         mr->VolHoles = 0;
         mr->EndBlock = 1;

         set_storageid_in_mr(NULL, mr);
         if (!db_update_media_record(ua->jcr, ua->db, mr)) {
            ua->error_msg(_("Can't update volume size in the catalog for Volume \"%s\"\n"),
               mr->VolumeName);
            ok = false;
         }
         /* Keep track of this important event */
         ua->send_events("DC0004", EVENTS_TYPE_COMMAND, "truncate volume=%s", mr->VolumeName);
         ua->send_msg(_("The volume \"%s\" has been truncated\n"), mr->VolumeName);
      }
   }
   if (!ok) {
      ua->warning_msg(_("Error truncating Volume \"%s\"\n"), mr->VolumeName);
   }
}

/*
 * Implement Bacula bconsole command  purge action
 *     purge action=truncate pool= volume= storage= mediatype=
 * or
 *     truncate [cache] pool= volume= storage= mediatype=
 *
 * If the keyword "cache:  is present, then we use the truncate
 *   command rather than relabel so that the driver can decide
 *   whether or not it wants to truncate.  Note: only the
 *   Cloud driver permits truncating the cache.
 *
 * Note, later we might want to rename this action_on_purge_cmd() as
 *  was the original, but only if we add additional actions such as
 *  erase, ... For the moment, we only do a truncate.
 *
 */
int truncate_cmd(UAContext *ua, const char *cmd)
{
   int drive = -1;
   int nb = 0;
   uint32_t *results = NULL;
   const char *action = "truncate";
   MEDIA_DBR mr;
   POOL_DBR pr;
   BSOCK *sd;
   char storage[MAX_NAME_LENGTH];

   if (find_arg(ua, "cache") > 0) {
      return cloud_volumes_cmd(ua, cmd, "truncate cache");
   }

   bmemset(&pr, 0, sizeof(pr));

   /*
    * Look for all Purged volumes that can be recycled, are enabled and
    *  have more than 1,000 bytes (i.e. actually have data).
    */
   mr.Recycle = 1;
   mr.Enabled = 1;
   mr.VolBytes = 1000;
   bstrncpy(mr.VolStatus, "Purged", sizeof(mr.VolStatus));
   /* Get list of volumes to truncate */
   if (!scan_storage_cmd(ua, cmd, true, /* allfrompool */
                         &drive, &mr, &pr, &action, storage, &nb, &results)) {
      goto bail_out;
   }

   if ((sd=open_sd_bsock(ua)) == NULL) {
      Dmsg0(100, "Can't open connection to sd\n");
      goto bail_out;
   }

   /*
    * Loop over the candidate Volumes and actually truncate them
    */
   for (int i=0; i < nb; i++) {
      mr.clear();
      mr.MediaId = results[i];
      if (db_get_media_record(ua->jcr, ua->db, &mr)) {
         if (strcasecmp(mr.VolStatus, "Purged") != 0) {
            ua->send_msg(_("Truncate Volume \"%s\" skipped. Status is \"%s\", but must be \"Purged\".\n"),
               mr.VolumeName, mr.VolStatus);
            continue;
         }
         if (drive < 0) {
            STORE *store = (STORE*)GetResWithName(R_STORAGE, storage);
            drive = get_storage_drive(ua, store);
         }

         /* Must select Pool if not already done */
         if (pr.PoolId == 0) {
            pr.PoolId = mr.PoolId;
            if (!db_get_pool_record(ua->jcr, ua->db, &pr)) {
               goto bail_out;   /* free allocated memory */
            }
         }
         if (strcasecmp("truncate", action) == 0) {
            truncate_volume(ua, &mr, pr.Name, storage,
                            drive, sd);
         }
      } else {
         Dmsg1(0, "Can't find MediaId=%lu\n", mr.MediaId);
      }
   }

bail_out:
   close_db(ua);
   close_sd_bsock(ua);
   ua->jcr->wstore = NULL;
   if (results) {
      free(results);
   }

   return 1;
}

/*
 * IF volume status is Append, Full, Used, or Error, mark it Purged
 *   Purged volumes can then be recycled (if enabled).
 */
bool mark_media_purged(UAContext *ua, MEDIA_DBR *mr)
{
   JCR *jcr = ua->jcr;
   if (strcmp(mr->VolStatus, "Append") == 0 ||
       strcmp(mr->VolStatus, "Full")   == 0 ||
       strcmp(mr->VolStatus, "Used")   == 0 ||
       strcmp(mr->VolStatus, "Error")  == 0) {
      bstrncpy(mr->VolStatus, "Purged", sizeof(mr->VolStatus));
      set_storageid_in_mr(NULL, mr);
      if (!db_update_media_record(jcr, ua->db, mr)) {
         return false;
      }
      pm_strcpy(jcr->VolumeName, mr->VolumeName);
      generate_plugin_event(jcr, bDirEventVolumePurged);
      /*
       * If the RecyclePool is defined, move the volume there
       */
      if (mr->RecyclePoolId && mr->RecyclePoolId != mr->PoolId) {
         POOL_DBR oldpr, newpr;
         bmemset(&oldpr, 0, sizeof(POOL_DBR));
         bmemset(&newpr, 0, sizeof(POOL_DBR));
         newpr.PoolId = mr->RecyclePoolId;
         oldpr.PoolId = mr->PoolId;
         if (   db_get_pool_numvols(jcr, ua->db, &oldpr)
             && db_get_pool_numvols(jcr, ua->db, &newpr)) {
            /* check if destination pool size is ok */
            if (newpr.MaxVols > 0 && newpr.NumVols >= newpr.MaxVols) {
               ua->error_msg(_("Unable move recycled Volume in full "
                              "Pool \"%s\" MaxVols=%d\n"),
                        newpr.Name, newpr.MaxVols);

            } else {            /* move media */
               update_vol_pool(ua, newpr.Name, mr, &oldpr);
            }
         } else {
            ua->error_msg("%s", db_strerror(ua->db));
         }
      }

      /* Send message to Job report, if it is a *real* job */
      if (jcr && jcr->JobId > 0) {
         Jmsg(jcr, M_INFO, 0, _("All records pruned from Volume \"%s\"; marking it \"Purged\"\n"),
            mr->VolumeName);
      }
      return true;
   } else {
      ua->error_msg(_("Cannot purge Volume with VolStatus=%s\n"), mr->VolStatus);
   }
   return strcmp(mr->VolStatus, "Purged") == 0;
}