serval-dna/rhizome_database.c

/*
Serval Rhizome file sharing
Copyright (C) 2012 The Serval Project
 
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any 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
GNU General Public License for more details.
 
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
*/

#include "serval.h"
#include "rhizome.h"
#include "strbuf.h"
#include <stdlib.h>

long long rhizome_space=0;
static const char *rhizome_thisdatastore_path = NULL;
static int rhizome_enabled_flag = -1; // unknown
#define SQLITE_CODE_OK(code) (code==SQLITE_OK || code==SQLITE_DONE)

int rhizome_enabled()
{
  if (rhizome_enabled_flag < 0)
    rhizome_enabled_flag = confValueGetBoolean("rhizome.enable", 1);
  return rhizome_enabled_flag;
}

const char *rhizome_datastore_path()
{
  if (!rhizome_thisdatastore_path)
    rhizome_set_datastore_path(NULL);
  return rhizome_thisdatastore_path;
}

int rhizome_set_datastore_path(const char *path)
{
  if (!path)
    path = confValueGet("rhizome.datastore_path", NULL);
  if (path) {
    rhizome_thisdatastore_path = strdup(path);
    if (path[0] != '/')
      WARNF("Dangerous rhizome.datastore_path setting: '%s' -- should be absolute", rhizome_thisdatastore_path);
  } else {
    rhizome_thisdatastore_path = serval_instancepath();
    WARNF("Rhizome datastore path not configured -- using instance path '%s'", rhizome_thisdatastore_path);
  }
  return 0;
}

int form_rhizome_datastore_path(char * buf, size_t bufsiz, const char *fmt, ...)
{
  va_list ap;
  strbuf b = strbuf_local(buf, bufsiz);
  strbuf_puts(b, rhizome_datastore_path());  
  if (fmt) {
    va_start(ap, fmt);
    if (*strbuf_substr(b, -1) != '/')
      strbuf_putc(b, '/');
    strbuf_vsprintf(b, fmt, ap);
    va_end(ap);
  }
  if (strbuf_overrun(b)) {
      WHY("Path buffer overrun");
      return 0;
  }
  return 1;
}

int form_rhizome_import_path(char * buf, size_t bufsiz, const char *fmt, ...)
{
  va_list ap;
  strbuf b = strbuf_local(buf, bufsiz);
  strbuf_sprintf(b, "%s/import", rhizome_datastore_path());
  if (fmt) {
    va_start(ap, fmt);
    strbuf_putc(b, '/');
    strbuf_vsprintf(b, fmt, ap);
    va_end(ap);
  }
  if (strbuf_overrun(b)) {
      WHY("Path buffer overrun");
      return 0;
  }
  return 1;
}

int create_rhizome_datastore_dir()
{
  if (debug & DEBUG_RHIZOME) DEBUGF("mkdirs(%s, 0700)", rhizome_datastore_path());
  return mkdirs(rhizome_datastore_path(), 0700);
}

int create_rhizome_import_dir()
{
  char dirname[1024];
  if (!form_rhizome_import_path(dirname, sizeof dirname, NULL))
    return -1;
  if (debug & DEBUG_RHIZOME) DEBUGF("mkdirs(%s, 0700)", dirname);
  return mkdirs(dirname, 0700);
}

sqlite3 *rhizome_db=NULL;

/* XXX Requires a messy join that might be slow. */
int rhizome_manifest_priority(char *id)
{
  long long result = 0;
  if (sqlite_exec_int64(&result,
	"select max(grouplist.priorty) from grouplist,manifests,groupmemberships"
	" where manifests.id='%s'"
	"   and grouplist.id=groupmemberships.groupid"
	"   and groupmemberships.manifestid=manifests.id;",
	id
      ) == -1
  )
    return -1;
  return (int) result;
}

int rhizome_opendb()
{
  if (rhizome_db) return 0;

  if (create_rhizome_datastore_dir() == -1)
    return WHY("No Directory");
  char dbname[1024];
  if (!FORM_RHIZOME_DATASTORE_PATH(dbname, "rhizome.db"))
    return WHY("Invalid path");

  if (sqlite3_open(dbname,&rhizome_db))
    return WHYF("SQLite could not open database: %s", sqlite3_errmsg(rhizome_db));

  /* Read Rhizome configuration */
  double rhizome_kb = atof(confValueGet("rhizome_kb", "1024"));
  rhizome_space = 1024LL * rhizome_kb;
  if (debug&DEBUG_RHIZOME) {
    DEBUGF("serval.conf:rhizome_kb=%.f", rhizome_kb);
    DEBUGF("Rhizome will use %lldB of storage for its database.", rhizome_space);
  }

  /* Create tables if required */
  if (sqlite3_exec(rhizome_db,
		   "PRAGMA auto_vacuum=2;"
		   "CREATE TABLE IF NOT EXISTS GROUPLIST(id text not null primary key, closed integer,ciphered integer,priority integer);"
		   
		   "CREATE TABLE IF NOT EXISTS MANIFESTS(id text not null primary key, manifest blob, version integer,inserttime integer, bar blob);"
		   
		   "CREATE TABLE IF NOT EXISTS FILES(id text not null primary key, data blob, length integer, highestpriority integer, datavalid integer);"
		   
		   "DROP TABLE IF EXISTS FILEMANIFESTS;"
		   "CREATE TABLE IF NOT EXISTS GROUPMEMBERSHIPS(manifestid text not null, groupid text not null);"
		   "CREATE TABLE IF NOT EXISTS VERIFICATIONS(sid text not null, did text, name text, starttime integer, endtime integer, signature blob);"
		   
		   ,NULL,NULL,NULL))
    {
      return WHYF("Failed to create required schema: %s", sqlite3_errmsg(rhizome_db));
    }
  // no easy way to tell if these columns already exist, should probably create some kind of schema version table
  // running this a second time will fail.
  sqlite3_exec(rhizome_db,
    "ALTER TABLE MANIFESTS ADD COLUMN filesize text;"
    "ALTER TABLE MANIFESTS ADD COLUMN filehash text;"
    "ALTER TABLE FILES ADD inserttime integer;"
	       ,NULL,NULL,NULL);
  
  if (sqlite3_exec(rhizome_db,
    "CREATE INDEX IF NOT EXISTS IDX_MANIFESTS_HASH ON MANIFESTS(filehash);"
    "DELETE FROM MANIFESTS WHERE filehash IS NULL;"
    "DELETE FROM FILES WHERE NOT EXISTS( SELECT  1 FROM MANIFESTS WHERE MANIFESTS.filehash = FILES.id);"
    "DELETE FROM MANIFESTS WHERE NOT EXISTS( SELECT  1 FROM FILES WHERE MANIFESTS.filehash = FILES.id);"
		   ,NULL,NULL,NULL)){
    return WHYF("Failed to create required schema: %s", sqlite3_errmsg(rhizome_db));
  }
  
  return 0;
}

/* 
   Convenience wrapper for executing an SQL command that returns a no value.
   Returns -1 if an error occurs, otherwise zero.
 */
int sqlite_exec_void(const char *sqlformat,...)
{
  if (!rhizome_db) rhizome_opendb();
  strbuf stmt = strbuf_alloca(8192);
  va_list ap;
  va_start(ap, sqlformat);
  strbuf_vsprintf(stmt, sqlformat, ap);
  va_end(ap);
  if (strbuf_overrun(stmt))
    return WHYF("Sql statement overrun: %s", strbuf_str(stmt));
  sqlite3_stmt *statement;
  
  switch (sqlite3_prepare_v2(rhizome_db, strbuf_str(stmt), -1, &statement, NULL)) {
    case SQLITE_OK: case SQLITE_DONE:
      break;
    default:
      WHY(strbuf_str(stmt));
      WHY(sqlite3_errmsg(rhizome_db));
      sqlite3_finalize(statement);
      return -1;
  }
  int stepcode;
  int rows = 0;
  while ((stepcode = sqlite3_step(statement)) == SQLITE_ROW)
    ++rows;
  if (rows) WARNF("query unexpectedly returned %d row%s", rows, rows == 1 ? "" : "s");
  switch (stepcode) {
    case SQLITE_OK:
    case SQLITE_DONE:
    case SQLITE_ROW:
      break;
    default:
      WHY(strbuf_str(stmt));
      WHY(sqlite3_errmsg(rhizome_db));
      sqlite3_finalize(statement);
      return -1;
  }
  sqlite3_finalize(statement);
  return 0;
}

/*
   Convenience wrapper for executing an SQL command that returns a single int64 value.
   Returns -1 if an error occurs.
   If no row is found, then returns 0 and does not alter *result.
   If exactly one row is found, the assigns its value to *result and returns 1.
   If more than one row is found, then assigns the value of the first row to *result and returns the
   number of rows.
 */
int sqlite_exec_int64(long long *result, const char *sqlformat,...)
{
  if (!rhizome_db) rhizome_opendb();
  strbuf stmt = strbuf_alloca(8192);
  va_list ap;
  va_start(ap, sqlformat);
  strbuf_vsprintf(stmt, sqlformat, ap);
  va_end(ap);
  if (strbuf_overrun(stmt))
    return WHYF("sql statement too long: %s", strbuf_str(stmt));
  sqlite3_stmt *statement;
  switch (sqlite3_prepare_v2(rhizome_db, strbuf_str(stmt), -1, &statement, NULL)) {
    case SQLITE_OK: case SQLITE_DONE: case SQLITE_ROW:
      break;
    default:
      WHY(strbuf_str(stmt));
      WHY(sqlite3_errmsg(rhizome_db));
      sqlite3_finalize(statement);
      return -1;
  }
  int stepcode;
  int rowcount = 0;
  if ((stepcode = sqlite3_step(statement)) == SQLITE_ROW) {
    int n = sqlite3_column_count(statement);
    if (n != 1) {
      sqlite3_finalize(statement);
      return WHYF("Incorrect column count %d (should be 1): %s", n, strbuf_str(stmt));
    }
    *result = sqlite3_column_int64(statement, 0);
    rowcount = 1;
    while ((stepcode = sqlite3_step(statement)) == SQLITE_ROW)
      ++rowcount;
  }
  switch (stepcode) {
    case SQLITE_OK: case SQLITE_DONE:
      break;
    default:
      WHY(strbuf_str(stmt));
      WHY(sqlite3_errmsg(rhizome_db));
      sqlite3_finalize(statement);
      return -1;
  }
  sqlite3_finalize(statement);
  return rowcount;
}

/* 
   Convenience wrapper for executing an SQL command that returns a single text value.
   Returns -1 if an error occurs, otherwise the number of rows that were found:
    0 means no rows, nothing is appended to the strbuf
    1 means exactly one row, and the its column is appended to the strbuf
    2 more than one row, and the first row's column is appended to the strbuf
   @author Andrew Bettison <andrew@servalproject.com>
 */
int sqlite_exec_strbuf(strbuf sb, const char *sqlformat,...)
{
  if (!rhizome_db) rhizome_opendb();
  strbuf stmt = strbuf_alloca(8192);
  va_list ap;
  va_start(ap, sqlformat);
  strbuf_vsprintf(stmt, sqlformat, ap);
  va_end(ap);
  if (strbuf_overrun(stmt))
    return WHYF("sql statement too long: %s", strbuf_str(stmt));
  sqlite3_stmt *statement;
  switch (sqlite3_prepare_v2(rhizome_db, strbuf_str(stmt), -1, &statement,NULL)) {
    case SQLITE_OK: case SQLITE_DONE: case SQLITE_ROW:
      break;
    default:
      sqlite3_finalize(statement);
      WHY(strbuf_str(stmt));
      WHY(sqlite3_errmsg(rhizome_db));
      return WHY("Could not prepare sql statement.");
  }
  int rows = 0;
  if (sqlite3_step(statement) == SQLITE_ROW) {
    int n = sqlite3_column_count(statement);
    if (n != 1) {
      sqlite3_finalize(statement);
      return WHYF("Incorrect column count %d (should be 1)", n);
    }
    strbuf_puts(sb, (const char *)sqlite3_column_text(statement, 0));
    sqlite3_finalize(statement);
    ++rows;
  }
  if (sqlite3_step(statement) == SQLITE_ROW)
    ++rows;
  sqlite3_finalize(statement);
  return rows;
}

long long rhizome_database_used_bytes()
{
  long long db_page_size=sqlite_exec_void("PRAGMA page_size;");
  long long db_page_count=sqlite_exec_void("PRAGMA page_count;");
  long long db_free_page_count=sqlite_exec_void("PRAGMA free_count;");
  return db_page_size*(db_page_count-db_free_page_count);
}

int rhizome_make_space(int group_priority, long long bytes)
{
  sqlite3_stmt *statement;

  /* Asked for impossibly large amount */
  if (bytes>=(rhizome_space-65536)) return -1;

  long long db_used=rhizome_database_used_bytes(); 
  
  /* If there is already enough space now, then do nothing more */
  if (db_used<=(rhizome_space-bytes-65536)) return 0;

  /* Okay, not enough space, so free up some. */
  char sql[1024];
  snprintf(sql,1024,"select id,length from files where highestpriority<%d order by descending length",group_priority);
  if(sqlite3_prepare_v2(rhizome_db,sql, -1, &statement, NULL) != SQLITE_OK )
    {
      WHYF("SQLite error running query '%s': %s",sql,sqlite3_errmsg(rhizome_db));
      sqlite3_finalize(statement);
      sqlite3_close(rhizome_db);
      rhizome_db=NULL;
      exit(-1);
    }

  while ( bytes>(rhizome_space-65536-rhizome_database_used_bytes()) && sqlite3_step(statement) == SQLITE_ROW)
    {
      /* Make sure we can drop this blob, and if so drop it, and recalculate number of bytes required */
      const unsigned char *id;
      //long long length;

      /* Get values */
      if (sqlite3_column_type(statement, 0)==SQLITE_TEXT) id=sqlite3_column_text(statement, 0);
      else {
	WARNF("Incorrect type in id column of files table.");
	continue; }
      if (sqlite3_column_type(statement, 1)==SQLITE_INTEGER) ;//length=sqlite3_column_int(statement, 1);
      else {
	WARNF("Incorrect type in length column of files table.");
	continue; }
      
      /* Try to drop this file from storage, discarding any references that do not trump the priority of this
	 request.  The query done earlier should ensure this, but it doesn't hurt to be paranoid, and it also
	 protects against inconsistency in the database. */
      rhizome_drop_stored_file((char *)id,group_priority+1);
    }
  sqlite3_finalize(statement);

  //long long equal_priority_larger_file_space_used = sqlite_exec_int64("SELECT COUNT(length) FROM FILES WHERE highestpriority=%d and length>%lld",group_priority,bytes);
  /* XXX Get rid of any equal priority files that are larger than this one */

  /* XXX Get rid of any higher priority files that are not relevant in this time or location */

  /* Couldn't make space */
  return WHY("Incomplete");
}

/* Drop the specified file from storage, and any manifests that reference it, 
   provided that none of those manifests are being retained at a higher priority
   than the maximum specified here. */
int rhizome_drop_stored_file(const char *id,int maximum_priority)
{
  char sql[1024];
  sqlite3_stmt *statement;
  int cannot_drop=0;

  if (strlen(id)>(crypto_hash_sha512_BYTES*2+1)) {
    WHY("File ID is wrong length");
    return -1;
  }

  snprintf(sql,1024,"select id from manifests where filehash='%s'", id);
  if(sqlite3_prepare_v2(rhizome_db,sql, -1, &statement, NULL) != SQLITE_OK )
    {
      WHYF("SQLite error running query '%s': %s",sql,sqlite3_errmsg(rhizome_db));
      sqlite3_finalize(statement);
      sqlite3_close(rhizome_db);
      rhizome_db=NULL;
      return WHY("Could not drop stored file");
    }

  while ( sqlite3_step(statement) == SQLITE_ROW)
    {
      /* Find manifests for this file */
      const unsigned char *manifestId;
      if (sqlite3_column_type(statement, 0)==SQLITE_TEXT)
	manifestId=sqlite3_column_text(statement, 0);
      else {
	WHYF("Incorrect type in id column of manifests table.");
	continue;
      }
            
      /* Check that manifest is not part of a higher priority group.
	 If so, we cannot drop the manifest or the file.
         However, we will keep iterating, as we can still drop any other manifests pointing to this file
	 that are lower priority, and thus free up a little space. */
      int priority = rhizome_manifest_priority((char *)manifestId);
      if (priority == -1)
	WHYF("Cannot drop due to error, manifestId=%s", manifestId);
      else if (priority > maximum_priority) {
	WHYF("Cannot drop due to manifest %s", manifestId);
	cannot_drop=1;
      } else {
	printf("removing stale manifests, groupmemberships\n");
	sqlite_exec_void("delete from manifests where id='%s';",manifestId);
	sqlite_exec_void("delete from keypairs where public='%s';",manifestId);
	sqlite_exec_void("delete from groupmemberships where manifestid='%s';",manifestId);
      }
    }
  sqlite3_finalize(statement);

  if (!cannot_drop) {
    sqlite_exec_void("delete from files where id='%s';",id);
  }
  return 0;
}


int sqlite3_exec_retry(sqlite3 *db,const char *sql,int (*callback)(void*,int,char**,char**),void *arg,char **errmsg){
  int ret;
  do{
    ret = sqlite3_exec(db, sql, callback, arg, errmsg);
  }while(ret==SQLITE_BUSY || ret==SQLITE_LOCKED);
  if (!SQLITE_CODE_OK(ret))
    WHY(sql);
  return ret;
}

int sqlite3_prepare_v2_retry(sqlite3 *db, const char *zSql, int nByte, sqlite3_stmt **ppStmt, const char **pzTail){
  int ret;
  do{
    ret = sqlite3_prepare_v2(db, zSql, nByte, ppStmt, pzTail);
  }while(ret==SQLITE_BUSY || ret==SQLITE_LOCKED);
  if (!SQLITE_CODE_OK(ret))
    WHY(zSql);
  return ret;
}

int sqlite3_step_retry(sqlite3_stmt *stmt){
  int ret;
  while(1){
    ret = sqlite3_step(stmt);
    if (ret==SQLITE_BUSY || ret==SQLITE_LOCKED){
      WHY("Database locked, retrying");
      sqlite3_reset(stmt);
    }else{
      return ret;
    }
  }
}

/*
  Store the specified manifest into the sqlite database.
  We assume that sufficient space has been made for us.
  The manifest should be finalised, and so we don't need to
  look at the underlying manifest file, but can just write m->manifest_data
  as a blob.

  associated_filename needs to be read in and stored as a blob.  Hopefully that
  can be done in pieces so that we don't have memory exhaustion issues on small
  architectures.  However, we do know it's hash apriori from m, and so we can
  skip loading the file in if it is already stored.  mmap() apparently works on
  Linux FAT file systems, and is probably the best choice since it doesn't need
  all pages to be in RAM at the same time.

  SQLite does allow modifying of blobs once stored in the database.
  The trick is to insert the blob as all zeroes using a special function, and then
  substitute bytes in the blog progressively.

  We need to also need to create the appropriate row(s) in the MANIFESTS, FILES, 
   and GROUPMEMBERSHIPS tables, and possibly GROUPLIST as well.
 */
int rhizome_store_bundle(rhizome_manifest *m)
{
  if (!m->finalised) return WHY("Manifest was not finalised");

  if (m->haveSecret) {
    /* We used to store the secret in the database, but we don't anymore, as we use 
     the BK field in the manifest. So nothing to do here. */
  } else {
    /* We don't have the secret for this manifest, so only allow updates if 
     the self-signature is valid */
    if (!m->selfSigned) {
      WHY("*** Insert into manifests failed (-2).");
      return WHY("Manifest is not signed, and I don't have the key.  Manifest might be forged or corrupt.");
    }
  }
  
  char manifestid[RHIZOME_MANIFEST_ID_STRLEN + 1];
  rhizome_manifest_get(m, "id", manifestid, sizeof manifestid);
  str_toupper_inplace(manifestid);

  char filehash[RHIZOME_FILEHASH_STRLEN + 1];
  strncpy(filehash, m->fileHexHash, sizeof filehash);
  str_toupper_inplace(filehash);

  
  char *err;
  int sql_ret;
  sqlite3_stmt *stmt;
  
  /* Bind BAR to data field */
  unsigned char bar[RHIZOME_BAR_BYTES];
  rhizome_manifest_to_bar(m,bar);

  // we should add the file in the same transaction, but closing the blob seems to cause some issues.
  /* Store the file */
  // TODO encrypted payloads - pass encryption key here
  if (m->fileLength>0){
    if (rhizome_store_file(m,NULL)){
      WHY("Could not store file");
      sql_ret = 1;
    }
  }
  
  if (!rhizome_db) rhizome_opendb();
  sql_ret = sqlite3_exec_retry(rhizome_db, "BEGIN TRANSACTION;", NULL, NULL, &err);
  
  if (SQLITE_CODE_OK(sql_ret)) sql_ret = sqlite3_prepare_v2_retry(rhizome_db, "INSERT OR REPLACE INTO MANIFESTS(id,manifest,version,inserttime,bar,filesize,filehash) VALUES(?,?,?,?,?,?,?);", -1, &stmt, NULL);
  if (SQLITE_CODE_OK(sql_ret)) sql_ret = sqlite3_bind_text(stmt, 1, manifestid, -1, SQLITE_TRANSIENT);
  if (SQLITE_CODE_OK(sql_ret)) sql_ret = sqlite3_bind_blob(stmt, 2, m->manifestdata, m->manifest_bytes, SQLITE_TRANSIENT);
  if (SQLITE_CODE_OK(sql_ret)) sql_ret = sqlite3_bind_int64(stmt, 3, m->version);
  if (SQLITE_CODE_OK(sql_ret)) sql_ret = sqlite3_bind_int64(stmt, 4, gettime_ms());
  if (SQLITE_CODE_OK(sql_ret)) sql_ret = sqlite3_bind_blob(stmt, 5, bar, RHIZOME_BAR_BYTES, SQLITE_TRANSIENT);
  if (SQLITE_CODE_OK(sql_ret)) sql_ret = sqlite3_bind_int64(stmt, 6, m->fileLength);
  if (SQLITE_CODE_OK(sql_ret)) sql_ret = sqlite3_bind_text(stmt, 7, filehash, -1, SQLITE_TRANSIENT);
  if (SQLITE_CODE_OK(sql_ret)) sql_ret = sqlite3_step_retry(stmt);
  if (SQLITE_CODE_OK(sql_ret)) sql_ret = sqlite3_finalize(stmt);
  
  // we might need to leave the old file around for a bit
  // clean out unreferenced files first
  if (SQLITE_CODE_OK(sql_ret)) sql_ret = sqlite3_prepare_v2_retry(rhizome_db, "DELETE FROM FILES WHERE inserttime < ? AND NOT EXISTS( SELECT  1 FROM MANIFESTS WHERE MANIFESTS.filehash = FILES.id);", -1, &stmt, NULL);
  if (SQLITE_CODE_OK(sql_ret)) sql_ret = sqlite3_bind_int64(stmt, 1, gettime_ms() - 60000);
  if (SQLITE_CODE_OK(sql_ret)) sql_ret = sqlite3_step_retry(stmt);
  if (SQLITE_CODE_OK(sql_ret)) sql_ret = sqlite3_finalize(stmt);
  
  if (rhizome_manifest_get(m,"isagroup",NULL,0)!=NULL) {
    int closed=rhizome_manifest_get_ll(m,"closedgroup");
    if (closed<1) closed=0;
    int ciphered=rhizome_manifest_get_ll(m,"cipheredgroup");
    if (ciphered<1) ciphered=0;
    if (SQLITE_CODE_OK(sql_ret)) sql_ret = sqlite3_prepare_v2_retry(rhizome_db, "INSERT OR REPLACE INTO GROUPLIST(id,closed,ciphered,priority) VALUES (?,?,?,?);", -1, &stmt, NULL);
    if (SQLITE_CODE_OK(sql_ret)) sql_ret = sqlite3_bind_text(stmt, 1, manifestid, -1, SQLITE_TRANSIENT);
    if (SQLITE_CODE_OK(sql_ret)) sql_ret = sqlite3_bind_int(stmt, 2, closed);
    if (SQLITE_CODE_OK(sql_ret)) sql_ret = sqlite3_bind_int(stmt, 3, ciphered);
    if (SQLITE_CODE_OK(sql_ret)) sql_ret = sqlite3_bind_int(stmt, 4, RHIZOME_PRIORITY_DEFAULT);
    if (SQLITE_CODE_OK(sql_ret)) sql_ret = sqlite3_step_retry(stmt);
    if (SQLITE_CODE_OK(sql_ret)) sql_ret = sqlite3_finalize(stmt);
  }

  if (m->group_count>0){
    if (SQLITE_CODE_OK(sql_ret)) sql_ret = sqlite3_prepare_v2_retry(rhizome_db, "INSERT OR REPLACE INTO GROUPMEMBERSHIPS(manifestid,groupid) VALUES(?, ?);", -1, &stmt, NULL);
    int i;
    for (i=0;i<m->group_count;i++){
      if (SQLITE_CODE_OK(sql_ret)) sql_ret = sqlite3_bind_text(stmt, 1, manifestid, -1, SQLITE_TRANSIENT);
      if (SQLITE_CODE_OK(sql_ret)) sql_ret = sqlite3_bind_text(stmt, 2, m->groups[i], -1, SQLITE_TRANSIENT);
      if (SQLITE_CODE_OK(sql_ret)) sql_ret = sqlite3_step_retry(stmt);
      if (SQLITE_CODE_OK(sql_ret)) sql_ret = sqlite3_reset(stmt);
    }
    if (SQLITE_CODE_OK(sql_ret)) sql_ret = sqlite3_finalize(stmt);
  }
  
  if (SQLITE_CODE_OK(sql_ret)) sql_ret = sqlite3_exec_retry(rhizome_db, "COMMIT;", NULL, NULL, &err);
  
  if (err!=NULL){
    WHY(err);
    sqlite3_free(err);
  }
  
  if (SQLITE_CODE_OK(sql_ret))
    return 0;
  
  WHYF("Failed to store bundle %s", sqlite3_errmsg(rhizome_db));
  
  sqlite3_exec_retry(rhizome_db, "ROLLBACK;", NULL, NULL, NULL);
  return -1;
}

int rhizome_finish_sqlstatement(sqlite3_stmt *statement)
{
  /* Do actual insert, and abort if it fails */
  int dud=0;
  int r;
  r=sqlite3_step(statement);
  switch(r) {
  case SQLITE_DONE: case SQLITE_ROW: case SQLITE_OK:
    break;
  default:
    WHY("sqlite3_step() failed.");
    WHY(sqlite3_errmsg(rhizome_db));
    dud++;
    sqlite3_finalize(statement);
  }

  if ((!dud)&&((r=sqlite3_finalize(statement))!=SQLITE_OK)) {
    WHY("sqlite3_finalize() failed.");
    WHY(sqlite3_errmsg(rhizome_db));
    dud++;
  }

  if (dud)  return WHY("SQLite3 could not complete statement.");
  return 0;
}

int rhizome_list_manifests(const char *service, const char *sender_sid, const char *recipient_sid, int limit, int offset)
{
  strbuf b = strbuf_alloca(1024);
  strbuf_sprintf(b, "SELECT id, manifest, version, inserttime FROM manifests ORDER BY inserttime DESC");
  if (limit)
    strbuf_sprintf(b, " LIMIT %u", limit);
  if (offset)
    strbuf_sprintf(b, " OFFSET %u", offset);
  if (strbuf_overrun(b))
    return WHYF("SQL command too long: ", strbuf_str(b));
  sqlite3_stmt *statement;
  const char *cmdtail;
  int ret = 0;
  if (sqlite3_prepare_v2(rhizome_db, strbuf_str(b), strbuf_len(b) + 1, &statement, &cmdtail) != SQLITE_OK) {
    sqlite3_finalize(statement);
    ret = WHY(sqlite3_errmsg(rhizome_db));
  } else {
    size_t rows = 0;
    cli_puts("10"); cli_delim("\n"); // number of columns
    cli_puts("service"); cli_delim(":");
    cli_puts("id"); cli_delim(":");
    cli_puts("version"); cli_delim(":");
    cli_puts("date"); cli_delim(":");
    cli_puts("_inserttime"); cli_delim(":");
    cli_puts("filesize"); cli_delim(":");
    cli_puts("filehash"); cli_delim(":");
    cli_puts("sender"); cli_delim(":");
    cli_puts("recipient"); cli_delim(":");
    cli_puts("name"); cli_delim("\n"); // should be last, because name may contain ':'
    while (sqlite3_step(statement) == SQLITE_ROW) {
      ++rows;
      if (!(   sqlite3_column_count(statement) == 4
	    && sqlite3_column_type(statement, 0) == SQLITE_TEXT
	    && sqlite3_column_type(statement, 1) == SQLITE_BLOB
	    && sqlite3_column_type(statement, 2) == SQLITE_INTEGER
	    && sqlite3_column_type(statement, 3) == SQLITE_INTEGER
      )) { 
	ret = WHY("Incorrect statement column");
	break;
      }
      rhizome_manifest *m = rhizome_new_manifest();
      if (m == NULL) {
	ret = WHY("Out of manifests");
	break;
      }
      const char *q_manifestid = (const char *) sqlite3_column_text(statement, 0);
      const char *manifestblob = (char *) sqlite3_column_blob(statement, 1);
      size_t manifestblobsize = sqlite3_column_bytes(statement, 1); // must call after sqlite3_column_blob()
      long long q_version = sqlite3_column_int64(statement, 2);
      long long q_inserttime = sqlite3_column_int64(statement, 3);
      if (rhizome_read_manifest_file(m, manifestblob, manifestblobsize) == -1) {
	WARNF("MANIFESTS row id=%s has invalid manifest blob -- skipped", q_manifestid);
      } else {
	long long blob_version = rhizome_manifest_get_ll(m, "version");
	if (blob_version != q_version)
	  WARNF("MANIFESTS row id=%s version=%lld does not match manifest blob.version=%lld", q_manifestid, q_version, blob_version);
	int match = 1;
	const char *blob_service = rhizome_manifest_get(m, "service", NULL, 0);
	if (service[0] && !(blob_service && strcasecmp(service, blob_service) == 0))
	  match = 0;
	
	const char *blob_sender = rhizome_manifest_get(m, "sender", NULL, 0);
	const char *blob_recipient = rhizome_manifest_get(m, "recipient", NULL, 0);
	
	if (match && sender_sid[0]) {
	  if (!(blob_sender && strcasecmp(sender_sid, blob_sender) == 0))
	    match = 0;
	}
	if (match && recipient_sid[0]) {
	  if (!(blob_recipient && strcasecmp(recipient_sid, blob_recipient) == 0))
	    match = 0;
	}
	
	if (match) {
	  const char *blob_name = rhizome_manifest_get(m, "name", NULL, 0);
	  long long blob_date = rhizome_manifest_get_ll(m, "date");
	  const char *blob_filehash = rhizome_manifest_get(m, "filehash", NULL, 0);
	  long long blob_filesize = rhizome_manifest_get_ll(m, "filesize");
	  DEBUGF("Manifest payload size = %lld",blob_filesize);
	  cli_puts(blob_service ? blob_service : ""); cli_delim(":");
	  cli_puts(q_manifestid); cli_delim(":");
	  cli_printf("%lld", blob_version); cli_delim(":");
	  cli_printf("%lld", blob_date); cli_delim(":");
	  cli_printf("%lld", q_inserttime); cli_delim(":");
	  cli_printf("%lld", blob_filesize); cli_delim(":");
	  cli_puts(blob_filehash ? blob_filehash : ""); cli_delim(":");
	  cli_puts(blob_sender ? blob_sender : ""); cli_delim(":");
	  cli_puts(blob_recipient ? blob_recipient : ""); cli_delim(":");
	  cli_puts(blob_name ? blob_name : ""); cli_delim("\n");
	}
      }
      if (m) rhizome_manifest_free(m);
    }
  }
  sqlite3_finalize(statement);
  return ret;
}

/* The following function just stores the file (or silently returns if it already exists).
   The relationships of manifests to this file are the responsibility of the caller. */
int rhizome_store_file(rhizome_manifest *m,const unsigned char *key)
{
  const char *file=m->dataFileName;
  const char *hash=m->fileHexHash;
  char hash_out[crypto_hash_sha512_BYTES*2+1];
  int priority=m->fileHighestPriority;
  if (m->payloadEncryption) 
    return WHY("Writing encrypted payloads not implemented");

  if (!m->fileHashedP)
    return WHY("Cannot store bundle file until it has been hashed");

  int fd=open(file,O_RDONLY);
  if (fd == -1) {
    WHY_perror("open");
    return WHY("Could not open associated file");
  }
  
  struct stat stat;
  if (fstat(fd,&stat)) {
    WHY_perror("fstat");
    close(fd);
    return WHY("Could not stat() associated file");
  }
  if (stat.st_size<m->fileLength) {
    return WHYF("File has shrunk, so cannot be stored.");
  } else if (stat.st_size>m->fileLength) {
    WARNF("File has grown by %lld bytes. I will just store the original number of bytes so that the hash (hopefully) matches",stat.st_size-m->fileLength);
  }

  unsigned char *addr = mmap(NULL, m->fileLength, PROT_READ, MAP_FILE|MAP_SHARED, fd, 0);
  if (addr==MAP_FAILED) {
    WHY_perror("mmap");
    close(fd);
    return WHY("mmap() of associated file failed.");
  }

  /* INSERT INTO FILES(id as text, data blob, length integer, highestpriority integer).
   BUT, we have to do this incrementally so that we can handle blobs larger than available memory. 
  This is possible using: 
     int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
  That binds an all zeroes blob to a field.  We can then populate the data by
  opening a handle to the blob using:
     int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
*/
  
  char sqlcmd[1024];
  const char *cmdtail;

  /* See if the file is already stored, and if so, don't bother storing it again */
  long long count = 0;
  if (sqlite_exec_int64(&count, "SELECT COUNT(*) FROM FILES WHERE id='%s' AND datavalid<>0;", hash) < 1) {
    close(fd);
    return WHY("Failed to count stored files");
  }
  if (count >= 1) {
    /* File is already stored, so just update the highestPriority field if required. */
    long long storedPriority = -1;
    if (sqlite_exec_int64(&storedPriority, "SELECT highestPriority FROM FILES WHERE id='%s' AND datavalid!=0", hash) == -1) {
      close(fd);
      return WHY("Failed to select highest priority");
    }
    if (storedPriority<priority) {
      if (sqlite_exec_void("UPDATE FILES SET highestPriority=%d WHERE id='%s';", priority, hash) == -1) {
	close(fd);
	return WHY("SQLite failed to update highestPriority field for stored file.");
      }
    }
    close(fd);
    return 0;
  }

  /* Okay, so there are no records that match, but we should delete any half-baked record (with datavalid=0) so that the insert below doesn't fail.
   Don't worry about the return result, since it might not delete any records. */
  sqlite3_exec(rhizome_db,"DELETE FROM FILES WHERE datavalid=0;",NULL,NULL,NULL);

  snprintf(sqlcmd,1024,"INSERT OR REPLACE INTO FILES(id,data,length,highestpriority,datavalid,inserttime) VALUES('%s',?,%lld,%d,0,%lld);",
	   hash,(long long)m->fileLength,priority,gettime_ms());
  sqlite3_stmt *statement;
  if (sqlite3_prepare_v2(rhizome_db,sqlcmd,strlen(sqlcmd)+1,&statement,&cmdtail) 
      != SQLITE_OK)
    {
      WHY(sqlite3_errmsg(rhizome_db));   
      sqlite3_finalize(statement);
      close(fd);
      return WHY("sqlite3_prepare_v2() failed");
    }
  
  /* Bind appropriate sized zero-filled blob to data field */
  int dud=0;
  int r;
  if ((r=sqlite3_bind_zeroblob(statement,1,m->fileLength))!=SQLITE_OK)
    {
      dud++;
      WHY(sqlite3_errmsg(rhizome_db));   
      WHY("sqlite3_bind_zeroblob() failed");
    }

  /* Do actual insert, and abort if it fails */
  if (!dud)
    switch(sqlite3_step(statement)) {
    case SQLITE_OK: case SQLITE_ROW: case SQLITE_DONE:
      break;
    default:
      dud++;
      WHY("sqlite3_step() failed");
      WHY(sqlite3_errmsg(rhizome_db));   
    }

  if (sqlite3_finalize(statement)) dud++;
  if (dud) {
    if (sqlite3_finalize(statement)!=SQLITE_OK)
      {
	WHY(sqlite3_errmsg(rhizome_db));
	WHY("sqlite3_finalize() failed");
      }
    close(fd);
    return WHY("SQLite3 failed to insert row for file");
  }

  /* Get rowid for inserted row, so that we can modify the blob */
  int rowid=sqlite3_last_insert_rowid(rhizome_db);
  if (rowid<1) {
    WHY(sqlite3_errmsg(rhizome_db));
    close(fd);
    return WHY("SQLite3 failed return rowid of inserted row");
  }

  sqlite3_blob *blob;
  if (sqlite3_blob_open(rhizome_db,"main","FILES","data",rowid,
		    1 /* read/write */,
			&blob) != SQLITE_OK)
    {
      WHY(sqlite3_errmsg(rhizome_db));
      sqlite3_blob_close(blob);
      close(fd);
      return WHY("SQLite3 failed to open file blob for writing");
    }

  unsigned char nonce[crypto_stream_xsalsa20_NONCEBYTES];
  bzero(nonce,crypto_stream_xsalsa20_NONCEBYTES);
  unsigned char buffer[RHIZOME_CRYPT_PAGE_SIZE];  

  /* Calculate hash of file as we go, so that we can report if
     the contents have changed during import.  This is also why we
     use the m->fileLength instead of size returned by stat, in case
     the file has been appended, e.g., if a journal is being appended to
     by a separate process.  This has already been shown to happen with
     Serval Maps, and it is also quite possible with MeshMS and other
     services. */
  {
    SHA512_CTX context;
    SHA512_Init(&context);

    long long i;
    for(i=0;i<m->fileLength;i+=RHIZOME_CRYPT_PAGE_SIZE)
      {
	int n=RHIZOME_CRYPT_PAGE_SIZE;
	if (i+n>m->fileLength) n=m->fileLength-i;
	SHA512_Update(&context, &addr[i], n);
	if (key) {
	  /* calculate block nonce */
	  int j; for(j=0;j<8;j++) nonce[i]=(i>>(j*8))&0xff;
	  crypto_stream_xsalsa20_xor(&addr[i],&buffer[0],n,
				     nonce,key);
	  if (sqlite3_blob_write(blob,&buffer[0],n,i) !=SQLITE_OK) dud++;
	}
	else 
	  if (sqlite3_blob_write(blob,&addr[i],n,i) !=SQLITE_OK) dud++;
      }
     SHA512_End(&context, (char *)hash_out);
     str_toupper_inplace(hash_out);
  }
  
  if (sqlite3_blob_close(blob)!=SQLITE_OK) dud++;
  
  close(fd);

  if (strcasecmp(hash_out,hash))
    {
      WHYF("Computed hash = %s",hash_out);
      return WHY("File hash does not match -- has file been modified while being stored?");
    }

  /* Mark file as up-to-date */
  if (sqlite_exec_void("UPDATE FILES SET datavalid=1 WHERE id='%s';", hash))
    return WHY("Failed to set datavalid");

  if (dud) {
      WHY(sqlite3_errmsg(rhizome_db));
      return WHY("SQLite3 failed write all blob data");
  }

  return 0;
}


void rhizome_bytes_to_hex_upper(unsigned const char *in, char *out, int byteCount)
{
  int i=0;
  for(i = 0; i != byteCount * 2 ; ++i)
    out[i] = nybltochar_upper((in[i >> 1] >> (4 - 4 * (i & 1))) & 0xf);
  out[i] = '\0';
}

int rhizome_update_file_priority(const char *fileid)
{
  /* work out the highest priority of any referrer */
  long long highestPriority = -1;
  if (sqlite_exec_int64(&highestPriority,
	"SELECT max(grouplist.priority) FROM MANIFESTS,GROUPMEMBERSHIPS,GROUPLIST"
	" where manifests.filehash='%s'"
	"   AND groupmemberships.manifestid=manifests.id"
	"   AND groupmemberships.groupid=grouplist.id;",
	fileid) == -1)
    return -1;
  if (highestPriority >= 0)
    return sqlite_exec_void("UPDATE files set highestPriority=%lld WHERE id='%s';", highestPriority, fileid);
  return 0;
}

/* Search the database for a manifest having the same name and payload content,
   and if the version is known, having the same version.

   @author Andrew Bettison <andrew@servalproject.com>
 */
int rhizome_find_duplicate(const rhizome_manifest *m, rhizome_manifest **found,
			   int checkVersionP)
{
  if (!m->fileHashedP)
    return WHY("Manifest payload is not hashed");
  const char *service = rhizome_manifest_get(m, "service", NULL, 0);
  const char *name = NULL;
  const char *sender = NULL;
  const char *recipient = NULL;
  if (service == NULL) {
    return WHY("Manifest has no service");
  } else if (strcasecmp(service, RHIZOME_SERVICE_FILE) == 0) {
    name = rhizome_manifest_get(m, "name", NULL, 0);
    if (!name) return WHY("Manifest has no name");
  } else if (strcasecmp(service, RHIZOME_SERVICE_MESHMS) == 0) {
    sender = rhizome_manifest_get(m, "sender", NULL, 0);
    recipient = rhizome_manifest_get(m, "recipient", NULL, 0);
    if (!sender) return WHY("Manifest has no sender");
    if (!recipient) return WHY("Manifest has no recipient");
  } else {
    return WHYF("Unsupported service '%s'", service);
  }
  char sqlcmd[1024];
  char *s = sqlcmd;
  s += snprintf(s, &sqlcmd[sizeof sqlcmd] - s,
      "SELECT id, manifest, version FROM manifests"
      " WHERE filehash = ?"
    );
  if (checkVersionP && s < &sqlcmd[sizeof sqlcmd])
    s += snprintf(s, sqlcmd + sizeof(sqlcmd) - s, " AND version = ?");
  if (s >= &sqlcmd[sizeof sqlcmd])
    return WHY("SQL command too long");
  int ret = 0;
  sqlite3_stmt *statement;
  const char *cmdtail;
  if (debug&DEBUG_RHIZOME) DEBUGF("sql query: %s",sqlcmd);
  if (sqlite3_prepare_v2(rhizome_db, sqlcmd, strlen(sqlcmd) + 1, &statement, &cmdtail) != SQLITE_OK) {
    ret = WHY(sqlite3_errmsg(rhizome_db));
  } else {
    char filehash[RHIZOME_FILEHASH_STRLEN + 1];
    strncpy(filehash, m->fileHexHash, sizeof filehash);
    str_toupper_inplace(filehash);
    if (debug & DEBUG_RHIZOME) DEBUGF("filehash=\"%s\"", filehash);
    sqlite3_bind_text(statement, 1, filehash, -1, SQLITE_STATIC);
    if (checkVersionP)
      sqlite3_bind_int64(statement, 2, m->version);
    size_t rows = 0;
    while (sqlite3_step(statement) == SQLITE_ROW) {
      ++rows;
      if (debug & DEBUG_RHIZOME) DEBUGF("Row %d", rows);
      if (!(   sqlite3_column_count(statement) == 3
	    && sqlite3_column_type(statement, 0) == SQLITE_TEXT
	    && sqlite3_column_type(statement, 1) == SQLITE_BLOB
	    && sqlite3_column_type(statement, 2) == SQLITE_INTEGER
      )) { 
	ret = WHY("Incorrect statement columns");
	break;
      }
      const char *q_manifestid = (const char *) sqlite3_column_text(statement, 0);
      size_t manifestidsize = sqlite3_column_bytes(statement, 0); // must call after sqlite3_column_text()
      if (manifestidsize != crypto_sign_edwards25519sha512batch_PUBLICKEYBYTES * 2) {
	ret = WHYF("Malformed manifest.id from query: %s", q_manifestid);
	break;
      }
      const char *manifestblob = (char *) sqlite3_column_blob(statement, 1);
      size_t manifestblobsize = sqlite3_column_bytes(statement, 1); // must call after sqlite3_column_blob()
      long long q_version = sqlite3_column_int64(statement, 2);
      rhizome_manifest *blob_m = rhizome_new_manifest();
      if (blob_m == NULL) {
	ret = WHY("Out of manifests");
	break;
      }
      if (rhizome_read_manifest_file(blob_m, manifestblob, manifestblobsize) == -1) {
	WARNF("MANIFESTS row id=%s has invalid manifest blob -- skipped", q_manifestid);
      } else if (rhizome_manifest_verify(blob_m)) {
	WARNF("MANIFESTS row id=%s fails verification -- skipped", q_manifestid);
      } else {
	const char *blob_service = rhizome_manifest_get(blob_m, "service", NULL, 0);
	const char *blob_id = rhizome_manifest_get(blob_m, "id", NULL, 0);
	long long blob_version = rhizome_manifest_get_ll(blob_m, "version");
	const char *blob_filehash = rhizome_manifest_get(blob_m, "filehash", NULL, 0);
	long long blob_filesize = rhizome_manifest_get_ll(blob_m, "filesize");
	if (debug & DEBUG_RHIZOME)
	  DEBUGF("Consider manifest.service=%s manifest.id=%s manifest.version=%lld", blob_service, q_manifestid, blob_version);
	/* Perform consistency checks, because we're paranoid. */
	int inconsistent = 0;
	if (blob_id && strcasecmp(blob_id, q_manifestid)) {
	  WARNF("MANIFESTS row id=%s has inconsistent blob with id=%s -- skipped", q_manifestid, blob_id);
	  ++inconsistent;
	}
	if (checkVersionP && blob_version != q_version) {
	  WARNF("MANIFESTS row id=%s has inconsistent blob: manifests.version=%lld, blob.version=%lld -- skipped",
		q_manifestid, q_version, blob_version);
	  ++inconsistent;
	}
	if (!blob_filehash && strcasecmp(blob_filehash, m->fileHexHash)) {
	  WARNF("MANIFESTS row id=%s joined to FILES row id=%s has inconsistent blob: blob.filehash=%s -- skipped",
		q_manifestid, m->fileHexHash, blob_filehash);
	  ++inconsistent;
	}
	if (blob_filesize != -1 && blob_filesize != m->fileLength) {
	  WARNF("MANIFESTS row id=%s joined to FILES row id=%s has inconsistent blob: known file size %lld, blob.filesize=%lld -- skipped",
		q_manifestid, m->fileHexHash, m->fileLength, blob_filesize);
	  ++inconsistent;
	}
	if (checkVersionP && q_version != m->version) {
	  WARNF("SELECT query with version=%lld returned incorrect row: manifests.version=%lld -- skipped", m->version, q_version);
	  ++inconsistent;
	}
	if (blob_service == NULL) {
	  WARNF("MANIFESTS row id=%s has blob with no 'service' -- skipped", q_manifestid, blob_id);
	  ++inconsistent;
	}
	if (!inconsistent) {
	  strbuf b = strbuf_alloca(1024);
	  if (strcasecmp(service, RHIZOME_SERVICE_FILE) == 0) {
	    const char *blob_name = rhizome_manifest_get(blob_m, "name", NULL, 0);
	    if (blob_name && !strcmp(blob_name, name)) {
	      if (debug & DEBUG_RHIZOME)
		strbuf_sprintf(b, " name=\"%s\"", blob_name);
	      ret = 1;
	    }
	  } else if (strcasecmp(service, RHIZOME_SERVICE_FILE) == 0) {
	    const char *blob_sender = rhizome_manifest_get(blob_m, "sender", NULL, 0);
	    const char *blob_recipient = rhizome_manifest_get(blob_m, "recipient", NULL, 0);
	    if (blob_sender && !strcasecmp(blob_sender, sender) && blob_recipient && !strcasecmp(blob_recipient, recipient)) {
	      if (debug & DEBUG_RHIZOME)
		strbuf_sprintf(b, " sender=%s recipient=%s", blob_sender, blob_recipient);
	      ret = 1;
	    }
	  }
	  if (ret == 1) {
	    rhizome_hex_to_bytes(q_manifestid, blob_m->cryptoSignPublic, crypto_sign_edwards25519sha512batch_PUBLICKEYBYTES*2); 
	    memcpy(blob_m->fileHexHash, m->fileHexHash, RHIZOME_FILEHASH_STRLEN + 1);
	    blob_m->fileHashedP = 1;
	    blob_m->fileLength = m->fileLength;
	    blob_m->version = q_version;
	    *found = blob_m;
	    DEBUGF("Found duplicate payload: service=%s%s version=%llu hexhash=%s",
		    blob_service, strbuf_str(b), blob_m->version, blob_m->fileHexHash
		  );
	    break;
	  }
	}
      }
      if (blob_m) rhizome_manifest_free(blob_m);
    }
  }
  sqlite3_finalize(statement);
  return ret;
}

/* Retrieve a manifest from the database, given its manifest ID.
 *
 * Returns 1 if manifest is found (if mp != NULL then a new manifest struct is allocated, made
 * finalisable and * assigned to *mp, caller is responsible for freeing).
 * Returns 0 if manifest is not found (*mp is unchanged).
 * Returns -1 on error (*mp is unchanged).
 */
int rhizome_retrieve_manifest(const char *manifestid, rhizome_manifest **mp)
{
  char sqlcmd[1024];
  int n = snprintf(sqlcmd, sizeof(sqlcmd), "SELECT id, manifest, version, inserttime FROM manifests WHERE id = ?");
  if (n >= sizeof(sqlcmd))
    return WHY("SQL command too long");
  sqlite3_stmt *statement;
  const char *cmdtail;
  int ret = 0;
  rhizome_manifest *m = NULL;
  if (sqlite3_prepare_v2(rhizome_db, sqlcmd, strlen(sqlcmd) + 1, &statement, &cmdtail) != SQLITE_OK) {
    sqlite3_finalize(statement);
    ret = WHY(sqlite3_errmsg(rhizome_db));
  } else {
    char manifestIdUpper[RHIZOME_MANIFEST_ID_STRLEN + 1];
    strncpy(manifestIdUpper, manifestid, sizeof manifestIdUpper);
    manifestIdUpper[RHIZOME_MANIFEST_ID_STRLEN] = '\0';
    str_toupper_inplace(manifestIdUpper);
    sqlite3_bind_text(statement, 1, manifestIdUpper, -1, SQLITE_STATIC);
    while (sqlite3_step(statement) == SQLITE_ROW) {
      if (!(   sqlite3_column_count(statement) == 4
	    && sqlite3_column_type(statement, 0) == SQLITE_TEXT
	    && sqlite3_column_type(statement, 1) == SQLITE_BLOB
	    && sqlite3_column_type(statement, 2) == SQLITE_INTEGER
	    && sqlite3_column_type(statement, 3) == SQLITE_INTEGER
      )) { 
	ret = WHY("Incorrect statement column");
	break;
      }
      const char *q_manifestid = (const char *) sqlite3_column_text(statement, 0);
      const char *manifestblob = (char *) sqlite3_column_blob(statement, 1);
      size_t manifestblobsize = sqlite3_column_bytes(statement, 1); // must call after sqlite3_column_blob()
      if (mp) {
	m = rhizome_new_manifest();
	if (m == NULL) {
	  WARNF("MANIFESTS row id=%s has invalid manifest blob -- skipped", q_manifestid);
	  ret = WHY("Out of manifests");
	} else if (rhizome_read_manifest_file(m, manifestblob, manifestblobsize) == -1) {
	  WARNF("MANIFESTS row id=%s has invalid manifest blob -- skipped", q_manifestid);
	  ret = WHY("Invalid manifest blob from database");
	} else {
	  ret = 1;
	  rhizome_hex_to_bytes(manifestid, m->cryptoSignPublic, crypto_sign_edwards25519sha512batch_PUBLICKEYBYTES*2); 
	  const char *blob_service = rhizome_manifest_get(m, "service", NULL, 0);
	  if (blob_service == NULL)
	    ret = WHY("Manifest is missing 'service' field");
	  const char *blob_filehash = rhizome_manifest_get(m, "filehash", NULL, 0);
	  if (blob_filehash == NULL)
	    ret = WHY("Manifest is missing 'filehash' field");
	  else {
	    memcpy(m->fileHexHash, blob_filehash, RHIZOME_FILEHASH_STRLEN + 1);
	    m->fileHashedP = 1;
	  }
	  long long blob_version = rhizome_manifest_get_ll(m, "version");
	  if (blob_version == -1)
	    ret = WHY("Manifest is missing 'version' field");
	  else
	    m->version = blob_version;
	  long long filesizeq = rhizome_manifest_get_ll(m, "filesize");
	  if (filesizeq == -1)
	    ret = WHY("Manifest is missing 'filesize' field");
	  else
	    m->fileLength = filesizeq;
	  if (ret == 1) {
	    cli_puts("service"); cli_delim(":");
	    cli_puts(blob_service); cli_delim("\n");
	    cli_puts("manifestid"); cli_delim(":");
	    cli_puts(q_manifestid); cli_delim("\n");
	    cli_puts("version"); cli_delim(":");
	    cli_printf("%lld", (long long) sqlite3_column_int64(statement, 2)); cli_delim("\n");
	    cli_puts("inserttime"); cli_delim(":");
	    cli_printf("%lld", (long long) sqlite3_column_int64(statement, 3)); cli_delim("\n");
	    cli_puts("filehash"); cli_delim(":");
	    cli_puts(m->fileHexHash); cli_delim("\n");
	    cli_puts("filesize"); cli_delim(":");
	    cli_printf("%lld", (long long) m->fileLength); cli_delim("\n");
	    // Could write the manifest blob to the CLI output here, but that would require the output to
	    // support byte[] fields as well as String fields.
	  }
	}
      }
      break;
    }
  }
  sqlite3_finalize(statement);
  if (mp && ret == 1)
    *mp = m;
  return ret;
}

/* Retrieve a file from the database, given its file hash.
 *
 * Returns 1 if file is found (contents are written to filepath if given).
 * Returns 0 if file is not found.
 * Returns -1 on error.
 */
int rhizome_retrieve_file(const char *fileid, const char *filepath,
			  const unsigned char *key)
{
  sqlite3_blob *blob=NULL;
  if (rhizome_update_file_priority(fileid) == -1) {
    WHY("Failed to update file priority");
    return 0;
  }
  char sqlcmd[1024];
  int n = snprintf(sqlcmd, sizeof(sqlcmd), "SELECT id, rowid, length FROM files WHERE id = ? AND datavalid != 0");
  if (n >= sizeof(sqlcmd))
    { WHY("SQL command too long"); return 0; }
  sqlite3_stmt *statement;
  const char *cmdtail;
  int ret = 0;
  if (sqlite3_prepare_v2(rhizome_db, sqlcmd, strlen(sqlcmd) + 1, &statement, &cmdtail) != SQLITE_OK) {
    ret = WHY(sqlite3_errmsg(rhizome_db));
  } else {
    char fileIdUpper[RHIZOME_FILEHASH_STRLEN + 1];
    strncpy(fileIdUpper, fileid, sizeof fileIdUpper);
    fileIdUpper[RHIZOME_FILEHASH_STRLEN] = '\0';
    str_toupper_inplace(fileIdUpper);
    sqlite3_bind_text(statement, 1, fileIdUpper, -1, SQLITE_STATIC);
    int stepcode = sqlite3_step(statement);
    if (stepcode != SQLITE_ROW) {
      WHY("File not found");
      ret = 0; /* no files returned */
    } else if (!(   sqlite3_column_count(statement) == 3
		    && sqlite3_column_type(statement, 0) == SQLITE_TEXT
		    && sqlite3_column_type(statement, 1) == SQLITE_INTEGER
		    && sqlite3_column_type(statement, 2) == SQLITE_INTEGER
		    )) { 
      WHY("Incorrect statement column");
      ret = 0; /* no files returned */
    } else {
      long long length = sqlite3_column_int64(statement, 2);
      long long rowid = sqlite3_column_int64(statement, 1);
      if (sqlite3_blob_open(rhizome_db,"main","files","data",rowid,
			    0 /* read only */,&blob)!=SQLITE_OK) {
	ret =0;
	WHY("Could not open blob for reading");
      }
      
      cli_puts("filehash"); cli_delim(":");
      cli_puts((const char *)sqlite3_column_text(statement, 0)); cli_delim("\n");
      cli_puts("filesize"); cli_delim(":");
      cli_printf("%lld", length); cli_delim("\n");
      ret = 1;
      if (filepath&&filepath[0]) {
	int fd = open(filepath, O_WRONLY | O_CREAT | O_TRUNC, 0775);
	if (fd == -1) {
	  WHY_perror("open");
	  ret = WHYF("Cannot open %s for write/create", filepath);
	} else {
	  /* read from blob and write to disk, decrypting if necessary as
	     we go.
	     Each 4KB block of data has a nonce which is fed with the key
	     into crypto_stream_xsalsa20().  The nonce is the file address
	     divided by 4KB.  This approach is used as it allows us to append
	     to files easily, without having to get the XOR stream for the whole
	     file, and without the cipher on existing bytes having to change.
	     Both of these are important properties for journal bundles, such as
	     will be used by MeshMS.  For non-journal bundles where it is important
	     that changing the payload changes the encryption key (so that the XOR
	     between any two versions of the payload cannot be easily obtained).
	     We will do this by having journal manifests identified, causing the
	     key to be locked, rather than based on the version number.
	     But anyway, we are supplied with the key here, so all we need to do
	     is do the block counting and call crypto_stream_xsalsa20().
	  */
	  long long offset;
	  unsigned char nonce[crypto_stream_xsalsa20_NONCEBYTES];
	  bzero(nonce,crypto_stream_xsalsa20_NONCEBYTES);
	  unsigned char buffer[RHIZOME_CRYPT_PAGE_SIZE];
	  for(offset=0;offset<length;offset+=RHIZOME_CRYPT_PAGE_SIZE)
	    {
	      long long count=length-offset;
	      if (count>RHIZOME_CRYPT_PAGE_SIZE) count=RHIZOME_CRYPT_PAGE_SIZE;
	      if(sqlite3_blob_read(blob,&buffer[0],count,offset)!=SQLITE_OK) {
		ret =0;
		WHYF("Error reading %lld bytes of data from blob at offset 0x%llx",
		     count, offset);
		WHYF("sqlite says: %s",sqlite3_errmsg(rhizome_db));
	      }
	      if (key) {
		/* calculate block nonce */
		int i; for(i=0;i<8;i++) nonce[i]=(offset>>(i*8))&0xff;
		crypto_stream_xsalsa20_xor(&buffer[0],&buffer[0],count,
					   nonce,key);
	      }
	      if (write(fd,buffer,count)!=count) {
		ret =0;
		WHY("Failed to write data to file");
	      }
	    } 
	  sqlite3_blob_close(blob); blob=NULL;
	}
	if (fd != -1 && close(fd) == -1) {
	  WHY_perror("close");
	  ret = 0; WHYF("Error flushing to %s ", filepath);
	}
      }
    }
  }
  if (blob) sqlite3_blob_close(blob);
  sqlite3_finalize(statement);
  return ret;
}