SQLite

         icu.o insert.o json1.o legacy.o loadext.o \
         main.o malloc.o mem0.o mem1.o mem2.o mem3.o mem5.o \
         memjournal.o \
         mutex.o mutex_noop.o mutex_unix.o mutex_w32.o \
         notify.o opcodes.o os.o os_unix.o os_win.o \
         pager.o pcache.o pcache1.o pragma.o prepare.o printf.o \
         random.o resolve.o rowset.o rtree.o select.o sqlite3rbu.o status.o \
	 server.o \
         table.o threads.o tokenize.o treeview.o trigger.o \
         update.o userauth.o util.o vacuum.o \
         vdbeapi.o vdbeaux.o vdbeblob.o vdbemem.o vdbesort.o \
	 vdbetrace.o wal.o walker.o where.o wherecode.o whereexpr.o \
         utf.o vtab.o

LIBOBJ += sqlite3session.o

  $(TOP)/src/pragma.h \
  $(TOP)/src/prepare.c \
  $(TOP)/src/printf.c \
  $(TOP)/src/random.c \
  $(TOP)/src/resolve.c \
  $(TOP)/src/rowset.c \
  $(TOP)/src/select.c \
  $(TOP)/src/server.c \
  $(TOP)/src/server.h \
  $(TOP)/src/status.c \
  $(TOP)/src/shell.c \
  $(TOP)/src/sqlite.h.in \
  $(TOP)/src/sqlite3ext.h \
  $(TOP)/src/sqliteInt.h \
  $(TOP)/src/sqliteLimit.h \
  $(TOP)/src/table.c \

#endif
  char *pTmpSpace;            /* Pager.pageSize bytes of space for tmp use */
  PCache *pPCache;            /* Pointer to page cache object */
#ifndef SQLITE_OMIT_WAL
  Wal *pWal;                  /* Write-ahead log used by "journal_mode=wal" */
  char *zWal;                 /* File name for write-ahead log */
#endif
#ifdef SQLITE_SERVER_EDITION
  Server *pServer;
#endif
};

/*
** Indexes for use with Pager.aStat[]. The Pager.aStat[] array contains
** the values accessed by passing SQLITE_DBSTATUS_CACHE_HIT, CACHE_MISS 
** or CACHE_WRITE to sqlite3_db_status().
*/

#else
# define pagerUseWal(x) 0
# define pagerRollbackWal(x) 0
# define pagerWalFrames(v,w,x,y) 0
# define pagerOpenWalIfPresent(z) SQLITE_OK
# define pagerBeginReadTransaction(z) SQLITE_OK
#endif

#ifdef SQLITE_SERVER_EDITION
# define pagerIsServer(x) ((x)->pServer!=0)
#else
# define pagerIsServer(x) 0
#endif

#ifndef NDEBUG 
/*
** Usage:
**
**   assert( assert_pager_state(pPager) );
**

*/
static int pagerUnlockDb(Pager *pPager, int eLock){
  int rc = SQLITE_OK;

  assert( !pPager->exclusiveMode || pPager->eLock==eLock );
  assert( eLock==NO_LOCK || eLock==SHARED_LOCK );
  assert( eLock!=NO_LOCK || pagerUseWal(pPager)==0 );
  assert( eLock!=NO_LOCK || pagerIsServer(pPager)==0 );
  if( isOpen(pPager->fd) ){
    assert( pPager->eLock>=eLock );
    rc = pPager->noLock ? SQLITE_OK : sqlite3OsUnlock(pPager->fd, eLock);
    if( pPager->eLock!=UNKNOWN_LOCK ){
      pPager->eLock = (u8)eLock;
    }
    IOTRACE(("UNLOCK %p %d\n", pPager, eLock))

       || pPager->eState==PAGER_ERROR 
  );

  sqlite3BitvecDestroy(pPager->pInJournal);
  pPager->pInJournal = 0;
  releaseAllSavepoints(pPager);

#ifdef SQLITE_SERVER_EDITION
  if( pagerIsServer(pPager) ){
    sqlite3ServerEnd(pPager->pServer);
    pPager->eState = PAGER_OPEN;
  }else 
#endif
  if( pagerUseWal(pPager) ){
    assert( !isOpen(pPager->jfd) );
    sqlite3WalEndReadTransaction(pPager->pWal);
    pPager->eState = PAGER_OPEN;
  }else if( !pPager->exclusiveMode ){
    int rc;                       /* Error code returned by pagerUnlockDb() */
    int iDc = isOpen(pPager->fd)?sqlite3OsDeviceCharacteristics(pPager->fd):0;

  }

  if( rc==SQLITE_OK && bCommit && isOpen(pPager->fd) ){
    rc = sqlite3OsFileControl(pPager->fd, SQLITE_FCNTL_COMMIT_PHASETWO, 0);
    if( rc==SQLITE_NOTFOUND ) rc = SQLITE_OK;
  }

#ifdef SQLITE_SERVER_EDITION
  if( pagerIsServer(pPager) ){
    rc2 = sqlite3ServerReleaseWriteLocks(pPager->pServer);
  }else
#endif
  if( !pPager->exclusiveMode 
   && (!pagerUseWal(pPager) || sqlite3WalExclusiveMode(pPager->pWal, 0))
  ){
    rc2 = pagerUnlockDb(pPager, SHARED_LOCK);
    pPager->changeCountDone = 0;
  }
  pPager->eState = PAGER_READER;

  pPager->exclusiveMode = 0;
#ifndef SQLITE_OMIT_WAL
  assert( db || pPager->pWal==0 );
  sqlite3WalClose(pPager->pWal, db, pPager->ckptSyncFlags, pPager->pageSize,
      (db && (db->flags & SQLITE_NoCkptOnClose) ? 0 : pTmp)
  );
  pPager->pWal = 0;
#endif
#ifdef SQLITE_SERVER_EDITION
  if( pPager->pServer ){
    sqlite3ServerDisconnect(pPager->pServer, pPager->fd);
    pPager->pServer = 0;
    sqlite3_free(pPager->zJournal);
  }
#endif
  pager_reset(pPager);
  if( MEMDB ){
    pager_unlock(pPager);
  }else{
    /* If it is open, sync the journal file before calling UnlockAndRollback.
    ** If this is not done, then an unsynced portion of the open journal 

        }
      }
    }
  }

  return rc;
}

#ifdef SQLITE_SERVER_EDITION
static int pagerServerConnect(Pager *pPager){
  int rc = SQLITE_OK;
  if( pPager->tempFile==0 ){
    int iClient = 0;
    pPager->noLock = 1;
    pPager->journalMode = PAGER_JOURNALMODE_PERSIST;
    rc = sqlite3ServerConnect(pPager, &pPager->pServer, &iClient);
    if( rc==SQLITE_OK ){
      pPager->zJournal = sqlite3_mprintf(
          "%s-journal%d", pPager->zFilename, iClient
      );
      if( pPager->zJournal==0 ){
        rc = SQLITE_NOMEM_BKPT;
      }
    }
  }
  return rc;
}

int sqlite3PagerRollbackJournal(Pager *pPager, int iClient){
  int rc;
  char *zJrnl = sqlite3_mprintf("%s-journal%d", pPager->zFilename, iClient);

  if( zJrnl ){
    int bExists = 0;
    sqlite3_file *jfd = 0;
    sqlite3_vfs * const pVfs = pPager->pVfs;

    rc = sqlite3OsAccess(pVfs, zJrnl, SQLITE_ACCESS_EXISTS, &bExists);
    if( rc==SQLITE_OK && bExists ){
      int flags = SQLITE_OPEN_READWRITE|SQLITE_OPEN_MAIN_JOURNAL;
      rc = sqlite3OsOpenMalloc(pVfs, zJrnl, &jfd, flags, &flags);
    }
    assert( rc==SQLITE_OK || jfd==0 );
    if( jfd ){
      sqlite3_file *saved_jfd = pPager->jfd;
      u8 saved_eState = pPager->eState;
      u8 saved_eLock = pPager->eLock;
      i64 saved_journalOff = pPager->journalOff;
      i64 saved_journalHdr = pPager->journalHdr;

      pPager->eLock = EXCLUSIVE_LOCK;
      pPager->eState = PAGER_WRITER_DBMOD;
      pPager->jfd = jfd;
      rc = pagerSyncHotJournal(pPager);
      if( rc==SQLITE_OK ) rc = pager_playback(pPager, 1);

      pPager->jfd = saved_jfd;
      pPager->eState = saved_eState;
      pPager->eLock = saved_eLock;
      pPager->journalOff = saved_journalOff;
      pPager->journalHdr = saved_journalHdr;

      sqlite3OsCloseFree(jfd);
      if( rc==SQLITE_OK ){
        rc = sqlite3OsDelete(pVfs, zJrnl, 0);
      }
    }
    sqlite3_free(zJrnl);
  }else{
    rc = SQLITE_NOMEM_BKPT;
  }

  return rc;
}

#else
# define pagerServerConnect(pPager) SQLITE_OK
#endif


/*
** This function is called to obtain a shared lock on the database file.
** It is illegal to call sqlite3PagerGet() until after this function
** has been successfully called. If a shared-lock is already held when
** this function is called, it is a no-op.
**

  ** be OPEN or READER. READER is only possible if the pager is or was in 
  ** exclusive access mode.  */
  assert( sqlite3PcacheRefCount(pPager->pPCache)==0 );
  assert( assert_pager_state(pPager) );
  assert( pPager->eState==PAGER_OPEN || pPager->eState==PAGER_READER );
  assert( pPager->errCode==SQLITE_OK );

  if( !pagerUseWal(pPager) && pPager->eState==PAGER_OPEN ){
  if( !pagerUseWal(pPager) 
   && !pagerIsServer(pPager) 
   && pPager->eState==PAGER_OPEN ){
    int bHotJournal = 1;          /* True if there exists a hot journal-file */

    assert( !MEMDB );
    assert( pPager->tempFile==0 || pPager->eLock==EXCLUSIVE_LOCK );

    rc = pager_wait_on_lock(pPager, SHARED_LOCK);
    if( rc!=SQLITE_OK ){

    /* If there is a WAL file in the file-system, open this database in WAL
    ** mode. Otherwise, the following function call is a no-op.
    */
    rc = pagerOpenWalIfPresent(pPager);
#ifndef SQLITE_OMIT_WAL
    assert( pPager->pWal==0 || rc==SQLITE_OK );
#endif
  }


    if( rc==SQLITE_OK && pagerUseWal(pPager)==0 ){
      rc = pagerServerConnect(pPager);
    }
  }

#ifdef SQLITE_SERVER_EDITION
  if( pagerIsServer(pPager) ){
    assert( rc==SQLITE_OK );
    pager_reset(pPager);
    rc = sqlite3ServerBegin(pPager->pServer);
  }else
#endif
  if( pagerUseWal(pPager) ){
    assert( rc==SQLITE_OK );
    rc = pagerBeginReadTransaction(pPager);
  }

  if( pPager->tempFile==0 && pPager->eState==PAGER_OPEN && rc==SQLITE_OK ){
    rc = pagerPagecount(pPager, &pPager->dbSize);

*/
int sqlite3PagerGet(
  Pager *pPager,      /* The pager open on the database file */
  Pgno pgno,          /* Page number to fetch */
  DbPage **ppPage,    /* Write a pointer to the page here */
  int flags           /* PAGER_GET_XXX flags */
){
#ifdef SQLITE_SERVER_EDITION
  if( pagerIsServer(pPager) ){
    int rc = sqlite3ServerLock(pPager->pServer, pgno, 0);
    if( rc!=SQLITE_OK ) return rc;
  }
#endif
  return pPager->xGet(pPager, pgno, ppPage, flags);
}

/*
** Acquire a page if it is already in the in-memory cache.  Do
** not read the page from disk.  Return a pointer to the page,
** or 0 if the page is not in cache. 

       || pPager->eState==PAGER_WRITER_CACHEMOD
       || pPager->eState==PAGER_WRITER_DBMOD
  );
  assert( assert_pager_state(pPager) );
  assert( pPager->errCode==0 );
  assert( pPager->readOnly==0 );
  CHECK_PAGE(pPg);

#ifdef SQLITE_SERVER_EDITION
  if( pagerIsServer(pPager) ){
    rc = sqlite3ServerLock(pPager->pServer, pPg->pgno, 1);
    if( rc!=SQLITE_OK ) return rc;
  }
#endif

  /* The journal file needs to be opened. Higher level routines have already
  ** obtained the necessary locks to begin the write-transaction, but the
  ** rollback journal might not yet be open. Open it now if this is the case.
  **
  ** This is done before calling sqlite3PcacheMakeDirty() on the page. 
  ** Otherwise, if it were done after calling sqlite3PcacheMakeDirty(), then

# define DIRECT_MODE 0
  assert( isDirectMode==0 );
  UNUSED_PARAMETER(isDirectMode);
#else
# define DIRECT_MODE isDirectMode
#endif

  if( 0==pagerIsServer(pPager) 
   && !pPager->changeCountDone 
  if( !pPager->changeCountDone && ALWAYS(pPager->dbSize>0) ){
   && ALWAYS(pPager->dbSize>0) 
  ){
    PgHdr *pPgHdr;                /* Reference to page 1 */

    assert( !pPager->tempFile && isOpen(pPager->fd) );

    /* Open page 1 of the file for writing. */
    rc = sqlite3PagerGet(pPager, 1, &pPgHdr, 0);
    assert( pPgHdr==0 || rc==SQLITE_OK );

  void sqlite3PagerRefdump(Pager*);
  void disable_simulated_io_errors(void);
  void enable_simulated_io_errors(void);
#else
# define disable_simulated_io_errors()
# define enable_simulated_io_errors()
#endif

#ifdef SQLITE_SERVER_EDITION
  int sqlite3PagerRollbackJournal(Pager*, int);
#endif

#endif /* SQLITE_PAGER_H */

/*
** 2017 April 24
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
*/

#include "sqliteInt.h"

/*
** HMA file layout:
**
**      4 bytes - DMS slot. All connections read-lock this slot.
**
**   16*4 bytes - locking slots. Connections hold a read-lock on a locking slot
**                when they are connected, a write lock when they have an open
**                transaction.
**
**    N*4 bytes - Page locking slots. N is HMA_PAGELOCK_SLOTS.
**
** Page lock slot format:
**
**    Least significant HMA_CLIENT_SLOTS used for read-locks. If bit 0 is set,
**    client 0 holds a read-lock.
**
**    If (v) is the value of the locking slot and (v>>HMA_CLIENT_SLOTS) is
**    not zero, then the write-lock holder is client ((v>>HMA_CLIENT_SLOTS)-1).
**
*/

#ifdef SQLITE_SERVER_EDITION

#define HMA_CLIENT_SLOTS   16
#define HMA_PAGELOCK_SLOTS (256*1024)

#define HMA_FILE_SIZE (4 + 4*HMA_CLIENT_SLOTS + 4*HMA_PAGELOCK_SLOTS)

#include "unistd.h"
#include "fcntl.h"
#include "sys/mman.h"
#include "sys/types.h"
#include "sys/stat.h"

typedef struct ServerHMA ServerHMA;

struct ServerGlobal {
  sqlite3_mutex *mutex;
  ServerHMA *pHma;
};
static struct ServerGlobal g_server;

/*
** There is one instance of the following structure for each distinct 
** HMA file opened by clients within this process. 
*/
struct ServerHMA {
  char *zName;                         /* hma file path */
  int fd;                              /* Fd open on hma file */
  int nClient;                         /* Current number of clients */
  Server *aClient[HMA_CLIENT_SLOTS];   /* Local (this process) clients */
  u32 *aMap;                           /* MMapped hma file */
  ServerHMA *pNext;                    /* Next HMA in this process */

  dev_t st_dev;
  ino_t st_ino;
};

struct Server {
  ServerHMA *pHma;                /* Hma file object */
  int iClient;                    /* Client id */
  Pager *pPager;                  /* Associated pager object */

  int nAlloc;                     /* Allocated size of aLock[] array */
  int nLock;                      /* Number of entries in aLock[] */
  u32 *aLock;                     /* Mapped lock file */
};

#define SERVER_WRITE_LOCK 3
#define SERVER_READ_LOCK  2
#define SERVER_NO_LOCK    1

static int posixLock(int fd, int iSlot, int eLock, int bBlock){
  int res;
  struct flock l;
  short aType[4] = {0, F_UNLCK, F_RDLCK, F_WRLCK};
  assert( eLock==SERVER_WRITE_LOCK 
       || eLock==SERVER_READ_LOCK 
       || eLock==SERVER_NO_LOCK 
  );
  memset(&l, 0, sizeof(l));
  l.l_type = aType[eLock];
  l.l_whence = SEEK_SET;
  l.l_start = iSlot*sizeof(u32);
  l.l_len = 1;

  res = fcntl(fd, (bBlock ? F_SETLKW : F_SETLK), &l);
  return (res==0 ? SQLITE_OK : SQLITE_BUSY);
}

static int serverMapFile(ServerHMA *p){
  assert( p->aMap==0 );
  p->aMap = mmap(0, HMA_FILE_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, p->fd, 0);
  if( p->aMap==0 ){
    return SQLITE_ERROR;
  }
  return SQLITE_OK;
}


static void serverDecrHmaRefcount(ServerHMA *pHma){
  if( pHma ){
    pHma->nClient--;
    if( pHma->nClient<=0 ){
      ServerHMA **pp;
      if( pHma->aMap ) munmap(pHma->aMap, HMA_FILE_SIZE);
      if( pHma->fd>=0 ) close(pHma->fd);
      for(pp=&g_server.pHma; *pp!=pHma; pp=&(*pp)->pNext);
      *pp = pHma->pNext;
      sqlite3_free(pHma);
    }
  }
}


static int serverOpenHma(Pager *pPager, const char *zPath, ServerHMA **ppHma){
  struct stat sStat;              /* Structure populated by stat() */
  int res;                        /* result of stat() */
  int rc = SQLITE_OK;             /* Return code */
  ServerHMA *pHma = 0;

  assert( sqlite3_mutex_held(g_server.mutex) );

  res = stat(zPath, &sStat);
  if( res!=0 ){
    sqlite3_log(SQLITE_CANTOPEN, "Failed to stat(%s)", zPath);
    rc = SQLITE_ERROR;
  }else{
    for(pHma=g_server.pHma; pHma; pHma=pHma->pNext){
      if( sStat.st_dev==pHma->st_dev && sStat.st_ino==pHma->st_ino ) break;
    }
    if( pHma==0 ){
      int nPath = strlen(zPath);
      int nByte = sizeof(ServerHMA) + nPath+1 + 4;

      pHma = (ServerHMA*)sqlite3_malloc(nByte);
      if( pHma==0 ){
        rc = SQLITE_NOMEM;
      }else{
        int i;
        memset(pHma, 0, nByte);
        pHma->zName = (char*)&pHma[1];
        pHma->nClient = 1;
        pHma->st_dev = sStat.st_dev;
        pHma->st_ino = sStat.st_ino;
        pHma->pNext = g_server.pHma;
        g_server.pHma = pHma;

        memcpy(pHma->zName, zPath, nPath);
        memcpy(&pHma->zName[nPath], "-hma", 5);

        pHma->fd = open(pHma->zName, O_RDWR|O_CREAT, 0644);
        if( pHma->fd<0 ){
          sqlite3_log(SQLITE_CANTOPEN, "Failed to open(%s)", pHma->zName);
          rc = SQLITE_ERROR;
        }

        if( rc==SQLITE_OK ){
          /* Write-lock the DMS slot. If successful, initialize the hma file. */
          rc = posixLock(pHma->fd, 0, SERVER_WRITE_LOCK, 0);
          if( rc==SQLITE_OK ){
            res = ftruncate(pHma->fd, HMA_FILE_SIZE);
            if( res!=0 ){
              sqlite3_log(SQLITE_CANTOPEN, 
                  "Failed to ftruncate(%s)", pHma->zName
              );
              rc = SQLITE_ERROR;
            }
            if( rc==SQLITE_OK ){
              rc = serverMapFile(pHma);
            }
            if( rc==SQLITE_OK ){
              memset(pHma->aMap, 0, HMA_FILE_SIZE);
            }else{
              rc = SQLITE_ERROR;
            }
          }else{
            rc = serverMapFile(pHma);
          }
          for(i=0; rc==SQLITE_OK && i<HMA_CLIENT_SLOTS; i++){
            rc = sqlite3PagerRollbackJournal(pPager, i);
          }
          if( rc==SQLITE_OK ){
            rc = posixLock(pHma->fd, 0, SERVER_READ_LOCK, 1);
          }
        }

        if( rc!=SQLITE_OK ){
          serverDecrHmaRefcount(pHma);
          pHma = 0;
        }
      }
    }else{
      pHma->nClient++;
    }
  }

  *ppHma = pHma;
  return rc;
}

static u32 *serverPageLockSlot(Server *p, Pgno pgno){
  int iSlot = pgno % HMA_PAGELOCK_SLOTS;
  return &p->pHma->aMap[1 + HMA_CLIENT_SLOTS + iSlot];
}
static u32 *serverClientSlot(Server *p, int iClient){
  return &p->pHma->aMap[1 + iClient];
}

/*
** Close the "connection" and *-hma file. This deletes the object passed
** as the first argument.
*/
void sqlite3ServerDisconnect(Server *p, sqlite3_file *dbfd){
  if( p->pHma ){
    ServerHMA *pHma = p->pHma;
    sqlite3_mutex_enter(g_server.mutex);
    if( p->iClient>=0 ){
      u32 *pSlot = serverClientSlot(p, p->iClient);
      *pSlot = 0;
      assert( pHma->aClient[p->iClient]==p );
      pHma->aClient[p->iClient] = 0;
      posixLock(pHma->fd, p->iClient+1, SERVER_NO_LOCK, 0);
    }
    if( dbfd 
     && pHma->nClient==1 
     && SQLITE_OK==sqlite3OsLock(dbfd, SQLITE_LOCK_EXCLUSIVE)
    ){
      unlink(pHma->zName);
    }
    serverDecrHmaRefcount(pHma);
    sqlite3_mutex_leave(g_server.mutex);
  }
  sqlite3_free(p->aLock);
  sqlite3_free(p);
}

static int serverRollbackClient(Server *p, int iBlock){
  int rc;

  sqlite3_log(SQLITE_NOTICE, "Rolling back failed client %d", iBlock);

  /* Roll back any journal file for client iBlock. */
  rc = sqlite3PagerRollbackJournal(p->pPager, iBlock);

  /* Clear any locks held by client iBlock from the HMA file.  */
  if( rc==SQLITE_OK ){
    int i;
    for(i=0; i<HMA_PAGELOCK_SLOTS; i++){
      u32 *pSlot = serverPageLockSlot(p, (Pgno)i);
      u32 v = *pSlot;
      while( 1 ){
        u32 n = v & ~(1 << iBlock);
        if( (v>>HMA_CLIENT_SLOTS)==iBlock+1 ){
          n = n & ((1<<HMA_CLIENT_SLOTS)-1);
        }
        if( __sync_val_compare_and_swap(pSlot, v, n)==v ) break;
        v = *pSlot;
      }
    }
  }

  return rc;
}


/*
** Open the *-hma file and "connect" to the system.
*/
int sqlite3ServerConnect(
  Pager *pPager, 
  Server **ppOut, 
  int *piClient
){
  const char *zPath = sqlite3PagerFilename(pPager, 0);
  int rc = SQLITE_OK;
  Server *p;

  p = (Server*)sqlite3_malloc(sizeof(Server));
  if( p==0 ){
    rc = SQLITE_NOMEM;
  }else{
    memset(p, 0, sizeof(Server));
    p->iClient = -1;
    p->pPager = pPager;

    sqlite3_mutex_enter(g_server.mutex);
    rc = serverOpenHma(pPager, zPath, &p->pHma);

    /* File is now mapped. Find a free client slot. */
    if( rc==SQLITE_OK ){
      int i;
      Server **aClient = p->pHma->aClient;
      int fd = p->pHma->fd;
      for(i=0; i<HMA_CLIENT_SLOTS; i++){
        if( aClient[i]==0 ){
          int res = posixLock(fd, i+1, SERVER_WRITE_LOCK, 0);
          if( res==SQLITE_OK ){
            u32 *pSlot = serverClientSlot(p, i);
            if( *pSlot ){
              rc = serverRollbackClient(p, i);
            }
            posixLock(fd, i+1, (!rc ? SERVER_READ_LOCK : SERVER_NO_LOCK), 0);
            break;
          }
        }
      }

      if( rc==SQLITE_OK ){
        if( i>HMA_CLIENT_SLOTS ){
          rc = SQLITE_BUSY;
        }else{
          u32 *pSlot = serverClientSlot(p, i);
          *piClient = p->iClient = i;
          aClient[i] = p;
          *pSlot = 1;
        }
      }
    }

    sqlite3_mutex_leave(g_server.mutex);
  }

  if( rc!=SQLITE_OK ){
    sqlite3ServerDisconnect(p, 0);
    p = 0;
  }
  *ppOut = p;
  return rc;
}

static int serverOvercomeLock(Server *p, int bWrite, u32 v, int *pbRetry){
  int rc = SQLITE_OK;
  int bLocal = 0;
  int iBlock = ((int)(v>>HMA_CLIENT_SLOTS))-1;

  if( iBlock<0 ){
    for(iBlock=0; iBlock<HMA_CLIENT_SLOTS; iBlock++){
      if( iBlock!=p->iClient && (v & (1<<iBlock)) ) break;
    }
  }
  assert( iBlock<HMA_CLIENT_SLOTS );

  sqlite3_mutex_enter(g_server.mutex);
  if( p->pHma->aClient[iBlock] ){
    bLocal = 1;
  }else{
    rc = posixLock(p->pHma->fd, iBlock+1, SERVER_WRITE_LOCK, 0);
  }

  if( bLocal==0 && rc==SQLITE_OK ){
    rc = serverRollbackClient(p, iBlock);

    /* Release the lock on slot iBlock */
    posixLock(p->pHma->fd, iBlock+1, SERVER_NO_LOCK, 0);
    if( rc==SQLITE_OK ){
      *pbRetry = 1;
    }
  }else{
    assert( rc==SQLITE_OK || rc==SQLITE_BUSY );
    rc = SQLITE_OK;
  }
  sqlite3_mutex_leave(g_server.mutex);

  return rc;
}

/*
** Begin a transaction.
*/
int sqlite3ServerBegin(Server *p){
  return posixLock(p->pHma->fd, p->iClient+1, SERVER_WRITE_LOCK, 0);
}

/*
** End a transaction (and release all locks).
*/
int sqlite3ServerEnd(Server *p){
  int i;
  for(i=0; i<p->nLock; i++){
    u32 *pSlot = serverPageLockSlot(p, p->aLock[i]);
    while( 1 ){
      u32 v = *pSlot;
      u32 n = v;
      if( (v>>HMA_CLIENT_SLOTS)==p->iClient+1 ){
        n = n & ((1 << HMA_CLIENT_SLOTS)-1);
      }
      n = n & ~(1 << p->iClient);
      if( __sync_val_compare_and_swap(pSlot, v, n)==v ) break;
    }
  }
  p->nLock = 0;
  return posixLock(p->pHma->fd, p->iClient+1, SERVER_READ_LOCK, 0);
}

/*
** Release all write-locks.
*/
int sqlite3ServerReleaseWriteLocks(Server *p){
  int rc = SQLITE_OK;
  return rc;
}

/*
** Lock page pgno for reading (bWrite==0) or writing (bWrite==1).
*/
int sqlite3ServerLock(Server *p, Pgno pgno, int bWrite){
  int rc = SQLITE_OK;

  /* Grow the aLock[] array, if required */
  if( p->nLock==p->nAlloc ){
    int nNew = p->nAlloc ? p->nAlloc*2 : 128;
    u32 *aNew;
    aNew = (u32*)sqlite3_realloc(p->aLock, sizeof(u32)*nNew);
    if( aNew==0 ){
      rc = SQLITE_NOMEM_BKPT;
    }else{
      p->aLock = aNew;
      p->nAlloc = nNew;
    }
  }
  if( rc==SQLITE_OK ){
    u32 *pSlot = serverPageLockSlot(p, pgno);
    u32 v = *pSlot;

    /* Check if the required lock is already held. If so, exit this function
    ** early. Otherwise, add an entry to the aLock[] array to record the fact
    ** that the lock may need to be released.  */
    if( bWrite ){
      int iLock = ((int)(v>>HMA_CLIENT_SLOTS)) - 1;
      if( iLock==p->iClient ) goto server_lock_out;
      if( iLock<0 ){
        p->aLock[p->nLock++] = pgno;
      }
    }else{
      if( v & (1<<p->iClient) ) goto server_lock_out;
      p->aLock[p->nLock++] = pgno;
    }

    while( 1 ){
      u32 n;

      while( (bWrite && (v & ~(1 << p->iClient))) || (v >> HMA_CLIENT_SLOTS) ){
        int bRetry = 0;
        rc = serverOvercomeLock(p, bWrite, v, &bRetry);
        if( rc!=SQLITE_OK ) goto server_lock_out;
        if( bRetry==0 ){
          /* There is a conflicting lock. Cannot obtain this lock. */
          sqlite3_log(SQLITE_BUSY_DEADLOCK, "Conflict at page %d", (int)pgno);
          rc = SQLITE_BUSY_DEADLOCK;
          goto server_lock_out;
        }
        v = *pSlot;
      }

      if( bWrite ){
        n = v | ((p->iClient+1) << HMA_CLIENT_SLOTS);
      }else{
        n = v | (1 << p->iClient);
      }
      if( __sync_val_compare_and_swap(pSlot, v, n)==v ) break;
      v = *pSlot;
    }
  }

server_lock_out:
  return rc;
}

#endif /* ifdef SQLITE_SERVER_EDITION */

#define SQLITE_IOERR_GETTEMPPATH       (SQLITE_IOERR | (25<<8))
#define SQLITE_IOERR_CONVPATH          (SQLITE_IOERR | (26<<8))
#define SQLITE_IOERR_VNODE             (SQLITE_IOERR | (27<<8))
#define SQLITE_IOERR_AUTH              (SQLITE_IOERR | (28<<8))
#define SQLITE_LOCKED_SHAREDCACHE      (SQLITE_LOCKED |  (1<<8))
#define SQLITE_BUSY_RECOVERY           (SQLITE_BUSY   |  (1<<8))
#define SQLITE_BUSY_SNAPSHOT           (SQLITE_BUSY   |  (2<<8))
#define SQLITE_BUSY_DEADLOCK           (SQLITE_BUSY   |  (3<<8))
#define SQLITE_CANTOPEN_NOTEMPDIR      (SQLITE_CANTOPEN | (1<<8))
#define SQLITE_CANTOPEN_ISDIR          (SQLITE_CANTOPEN | (2<<8))
#define SQLITE_CANTOPEN_FULLPATH       (SQLITE_CANTOPEN | (3<<8))
#define SQLITE_CANTOPEN_CONVPATH       (SQLITE_CANTOPEN | (4<<8))
#define SQLITE_CORRUPT_VTAB            (SQLITE_CORRUPT | (1<<8))
#define SQLITE_READONLY_RECOVERY       (SQLITE_READONLY | (1<<8))
#define SQLITE_READONLY_CANTLOCK       (SQLITE_READONLY | (2<<8))

*/
#include "btree.h"
#include "vdbe.h"
#include "pager.h"
#include "pcache.h"
#include "os.h"
#include "mutex.h"
#include "server.h"

/* The SQLITE_EXTRA_DURABLE compile-time option used to set the default
** synchronous setting to EXTRA.  It is no longer supported.
*/
#ifdef SQLITE_EXTRA_DURABLE
# warning Use SQLITE_DEFAULT_SYNCHRONOUS=3 instead of SQLITE_EXTRA_DURABLE
# define SQLITE_DEFAULT_SYNCHRONOUS 3

    /* Lock all btrees used by the statement */
    sqlite3VdbeEnter(p);

    /* Check for one of the special errors */
    mrc = p->rc & 0xff;
    isSpecialError = mrc==SQLITE_NOMEM || mrc==SQLITE_IOERR
                     || mrc==SQLITE_INTERRUPT || mrc==SQLITE_FULL;
                     || mrc==SQLITE_INTERRUPT || mrc==SQLITE_FULL
                     || p->rc==SQLITE_BUSY_DEADLOCK;
    if( isSpecialError ){
      /* If the query was read-only and the error code is SQLITE_INTERRUPT, 
      ** no rollback is necessary. Otherwise, at least a savepoint 
      ** transaction must be rolled back to restore the database to a 
      ** consistent state.
      /* If the query was read-only and the error code is SQLITE_INTERRUPT
      ** or SQLITE_BUSY_SERVER, no rollback is necessary. Otherwise, at 
      ** least a savepoint transaction must be rolled back to restore the
      ** database to a consistent state.
      **
      ** Even if the statement is read-only, it is important to perform
      ** a statement or transaction rollback operation. If the error 
      ** occurred while writing to the journal, sub-journal or database
      ** file as part of an effort to free up cache space (see function
      ** pagerStress() in pager.c), the rollback is required to restore 
      ** the pager to a consistent state.
      */
      if( !p->readOnly || mrc!=SQLITE_INTERRUPT ){
      if( !p->readOnly || (mrc!=SQLITE_INTERRUPT && mrc!=SQLITE_BUSY) ){
        if( (mrc==SQLITE_NOMEM || mrc==SQLITE_FULL) && p->usesStmtJournal ){
          eStatementOp = SAVEPOINT_ROLLBACK;
        }else{
          /* We are forced to roll back the active transaction. Before doing
          ** so, abort any other statements this handle currently has active.
          */
          sqlite3RollbackAll(db, SQLITE_ABORT_ROLLBACK);

  fts3corrupt3.test
  fts3misc.test
}

test_suite "fts5" -prefix "" -description {
  All FTS5 tests.
} -files [glob -nocomplain $::testdir/../ext/fts5/test/*.test]

test_suite "server" -prefix "" -description {
  All server-edition tests.
} -files [
  test_set \
      [glob -nocomplain $::testdir/server*.test] \
      -exclude *server1.test
]

test_suite "fts5-light" -prefix "" -description {
  All FTS5 tests.
} -files [
  test_set \
      [glob -nocomplain $::testdir/../ext/fts5/test/*.test] \
      -exclude *corrupt* *fault* *big* *fts5aj*

# 2017 April 25
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this script is testing the server mode of SQLite.
#


set testdir [file dirname $argv0]
source $testdir/tester.tcl
set testprefix server2

#-------------------------------------------------------------------------
# Check that the *-hma file is deleted correctly.
#
do_execsql_test 1.0 {
  CREATE TABLE t1(a, b);
} {}
do_test 1.1 {
  file exists test.db-hma
} {1}
do_test 1.2 {
  db close
  file exists test.db-hma
} {0}
do_test 1.3 {
  sqlite3 db test.db
  db eval { CREATE TABLE t2(a, b) }
  sqlite3 db2 test.db
  db2 eval { CREATE TABLE t3(a, b) }
  file exists test.db-hma
} {1}
do_test 1.4 {
  db2 close
  file exists test.db-hma
} {1}
do_test 1.5 {
  db close
  file exists test.db-hma
} {0}


#-------------------------------------------------------------------------
#
reset_db
sqlite3 db2 test.db

do_execsql_test 2.0 {
  CREATE TABLE t1(a, b);
  CREATE TABLE t2(c, d);
}

# Two concurrent transactions committed.
#
do_test 2.1 {
  db eval {
    BEGIN;
      INSERT INTO t1 VALUES(1, 2);
  }
  db2 eval {
    BEGIN;
      INSERT INTO t2 VALUES(3, 4);
  }
} {}
do_test 2.2 {
  lsort [glob test.db*]
} {test.db test.db-hma test.db-journal0 test.db-journal1}
do_test 2.3.1 { db eval COMMIT  } {}
do_test 2.3.2 { db2 eval COMMIT } {}
do_execsql_test 2.4 {SELECT * FROM t1, t2} {1 2 3 4}
do_test 2.5 {
  lsort [glob test.db*]
} {test.db test.db-hma test.db-journal0 test.db-journal1}

do_test 2.6 {
  execsql {BEGIN}
  execsql {INSERT INTO t1 VALUES(5, 6)}

  execsql {BEGIN} db2
  catchsql {INSERT INTO t1 VALUES(7, 8)} db2
} {1 {database is locked}}
do_test 2.7 {
  # Transaction is automatically rolled back in this case.
  sqlite3_get_autocommit db2
} {1}
do_test 2.8 {
  execsql COMMIT
  execsql { SELECT * FROM t1 } db2
} {1 2 5 6}



finish_test

# 2017 April 25
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this script is testing the server mode of SQLite.
#


set testdir [file dirname $argv0]
source $testdir/tester.tcl
source $testdir/lock_common.tcl
set testprefix server3

db close

do_multiclient_test tn {
  do_test $tn.1 {
    sql1 { CREATE TABLE t1(a, b) }
    sql2 { CREATE TABLE t2(a, b) }
  } {}

  do_test $tn.2 {
    sql1 {
      INSERT INTO t2 VALUES(1, 2);
      BEGIN;
        INSERT INTO t1 VALUES(1, 2);
    }
  } {}

  do_test $tn.3 { csql2 { SELECT * FROM t1 } } {1 {database is locked}}
  do_test $tn.4 { csql2 { SELECT * FROM t1 } } {1 {database is locked}}
  do_test $tn.5 {  sql2 { SELECT * FROM t2 } } {1 2}


}

finish_test

# 2017 April 27
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
#


set testdir [file dirname $argv0]
source $testdir/tester.tcl
set testprefix servercrash

ifcapable !crashtest {
  finish_test
  return
}
do_not_use_codec

do_execsql_test 1.0 {
  PRAGMA page_siBlockze = 4096;
  PRAGMA auto_vacuum = OFF;
  CREATE TABLE t1(a, b);
  CREATE TABLE t2(c, d);

  INSERT INTO t1 VALUES(1, 2), (3, 4);
  INSERT INTO t2 VALUES(1, 2), (3, 4);
}

for {set i 0} {$i < 10} {incr i} {
  do_test 1.$i.1 {
    crashsql -delay 1 -file test.db { INSERT INTO t1 VALUES(5, 6) }
  } {1 {child process exited abnormally}}

  do_execsql_test 1.$i.2 {
    SELECT * FROM t1
  } {1 2 3 4}
}

for {set i 0} {$i < 10} {incr i} {
  do_test 2.$i.1 {
    crashsql -delay 1 -file test.db { INSERT INTO t1 VALUES(5, 6) }
  } {1 {child process exited abnormally}}

  do_test 2.$i.2 {
    sqlite3 dbX test.db
    execsql { SELECT * FROM t1 } dbX
  } {1 2 3 4}
  dbX close
}

db close
for {set i 0} {$i < 10} {incr i} {
  do_test 3.$i.1 {
    crashsql -delay 1 -file test.db { INSERT INTO t1 VALUES(5, 6) }
  } {1 {child process exited abnormally}}

  sqlite3 db test.db
  do_execsql_test 3.$i.2 { SELECT * FROM t1 } {1 2 3 4}
  db close
}

finish_test

# Create a test database
#
proc reset_db {} {
  catch {db close}
  forcedelete test.db
  forcedelete test.db-journal
  forcedelete test.db-wal
  for {set i 0} {$i < 16} {incr i} {
    forcedelete test.db-journal$i
  }

  sqlite3 db ./test.db
  set ::DB [sqlite3_connection_pointer db]
  if {[info exists ::SETUP_SQL]} {
    db eval $::SETUP_SQL
  }
}
reset_db

   os_win.h
   os.h
   pager.h
   parse.h
   pcache.h
   pragma.h
   rtree.h
   server.h
   sqlite3session.h
   sqlite3.h
   sqlite3ext.h
   sqlite3rbu.h
   sqliteicu.h
   sqliteInt.h
   sqliteLimit.h

   bitvec.c
   pcache.c
   pcache1.c
   rowset.c
   pager.c
   wal.c
   server.c

   btmutex.c
   btree.c
   backup.c

   vdbemem.c
   vdbeaux.c