SQLite

  return TCL_OK;

 bad_args:
  Tcl_WrongNumArgs(interp, 1, objv, "VFSNAME ?-noshm BOOL? ?-fullshm BOOL? ?-default BOOL? ?-mxpathname INT? ?-szosfile INT? ?-iversion INT?");
  return TCL_ERROR;
}

extern int getDbPointer(Tcl_Interp *interp, const char *zA, sqlite3 **ppDb);
extern const char *sqlite3ErrName(int);

/*
** tclcmd: vfs_shmlock DB DBNAME (shared|exclusive) (lock|unlock) OFFSET N
*/
static int SQLITE_TCLAPI test_vfs_shmlock(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  const char *azArg1[] = {"shared", "exclusive", 0};
  const char *azArg2[] = {"lock", "unlock", 0};
  sqlite3 *db = 0;
  int rc = SQLITE_OK;
  const char *zDbname = 0;
  int iArg1 = 0;
  int iArg2 = 0;
  int iOffset = 0;
  int n = 0;
  sqlite3_file *pFd;

  if( objc!=7 ){
    Tcl_WrongNumArgs(interp, 1, objv, 
        "DB DBNAME (shared|exclusive) (lock|unlock) OFFSET N"
    );
    return TCL_ERROR;
  }

  zDbname = Tcl_GetString(objv[2]);
  if( getDbPointer(interp, Tcl_GetString(objv[1]), &db) 
   || Tcl_GetIndexFromObj(interp, objv[3], azArg1, "ARG", 0, &iArg1) 
   || Tcl_GetIndexFromObj(interp, objv[4], azArg2, "ARG", 0, &iArg2) 
   || Tcl_GetIntFromObj(interp, objv[5], &iOffset)
   || Tcl_GetIntFromObj(interp, objv[6], &n)
  ){
    return TCL_ERROR;
  }

  sqlite3_file_control(db, zDbname, SQLITE_FCNTL_FILE_POINTER, (void*)&pFd);
  if( pFd==0 ){
    return TCL_ERROR;
  }
  rc = pFd->pMethods->xShmLock(pFd, iOffset, n, 
      (iArg1==0 ? SQLITE_SHM_SHARED : SQLITE_SHM_EXCLUSIVE)
    | (iArg2==0 ? SQLITE_SHM_LOCK : SQLITE_SHM_UNLOCK)
  );
  Tcl_SetObjResult(interp, Tcl_NewStringObj(sqlite3ErrName(rc), -1));
  return TCL_OK;
}


int Sqlitetestvfs_Init(Tcl_Interp *interp){
  Tcl_CreateObjCommand(interp, "testvfs", testvfs_cmd, 0, 0);
  Tcl_CreateObjCommand(interp, "vfs_shmlock", test_vfs_shmlock, 0, 0);
  return TCL_OK;
}

#endif

# This file contains code used by several different test scripts. The
# code in this file allows testfixture to control another process (or
# processes) to test locking.
#

proc do_multiclient_test {varname script} {

  foreach {tn code} [list 1 {
    if {[info exists ::G(valgrind)]} { db close ; continue }
    set ::code2_chan [launch_testfixture]
    set ::code3_chan [launch_testfixture]
    proc code2 {tcl} { testfixture $::code2_chan $tcl }
    proc code3 {tcl} { testfixture $::code3_chan $tcl }

  } 2 {
    proc code2 {tcl} { uplevel #0 $tcl }
    proc code3 {tcl} { uplevel #0 $tcl }

  }] {
    # Do not run multi-process tests with the unix-excl VFS.
    #
    if {$tn==1 && [permutation]=="unix-excl"} continue

    faultsim_delete_and_reopen

    proc code1 {tcl} { uplevel #0 $tcl }
  
    # Open connections [db2] and [db3]. Depending on which iteration this
    # is, the connections may be created in this interpreter, or in 
    # interpreters running in other OS processes. As such, the [db2] and [db3]

# 2018 December 6
#
# 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 shmlock

ifcapable !wal {finish_test ; return }

sqlite3 db2 test.db
sqlite3 db3 test.db

do_execsql_test 1.0 {
  PRAGMA journal_mode = wal;
  CREATE TABLE t1(a, b);
  INSERT INTO t1 VALUES(1, 2);
} {wal}
do_test 1.1 { execsql { SELECT * FROM t1 } db2 } {1 2}
do_test 1.2 { execsql { SELECT * FROM t1 } db3 } {1 2}

foreach {tn dbhandle cmd res} {
  1    db  {shared    lock   7 1}    OK
  2    db2 {exclusive lock   7 1}    BUSY
  3    db  {shared    unlock 7 1}    OK
  4    db2 {exclusive lock   7 1}    OK
  5    db  {shared    lock   7 1}    BUSY
  6    db  {exclusive lock   7 1}    BUSY
  7    db2 {exclusive unlock 7 1}    OK

  8    db  {exclusive lock   0 8}    OK
  9    db  {exclusive unlock 0 8}    OK
  10   db2 {exclusive lock   0 8}    OK
  11   db2 {exclusive unlock 0 8}    OK

  12   db  {shared    lock   0 1}    OK
  13   db2 {shared    lock   0 1}    OK
  14   db3 {shared    lock   0 1}    OK
  15   db3 {shared    unlock 0 1}    OK
  16   db3 {exclusive lock   0 1}    BUSY
  17   db2 {shared    unlock 0 1}    OK
  18   db3 {exclusive lock   0 1}    BUSY
  19   db  {shared    unlock 0 1}    OK
  20   db3 {exclusive lock   0 1}    OK
  21   db3 {exclusive unlock 0 1}    OK

  22   db  {shared    lock   3 1}    OK
  23   db2 {exclusive lock   2 2}    BUSY
  24   db  {shared    lock   2 1}    OK
  25   db2 {exclusive lock   0 5}    BUSY
  26   db2 {exclusive lock   0 4}    BUSY
  27   db2 {exclusive lock   0 3}    BUSY
  28   db  {shared    unlock 3 1}    OK
  29   db2 {exclusive lock   2 2}    BUSY
  28   db  {shared    unlock 2 1}    OK
  29   db2 {exclusive lock   2 2}    OK
  29   db2 {exclusive unlock 2 2}    OK
} {
  do_test 1.3.$tn [list vfs_shmlock $dbhandle main {*}$cmd] "SQLITE_$res"
}

db  close
db2 close
db3 close

if {[permutation]=="unix-excl"} {
  do_test 2.0 {
    for {set i 0} {$i < 256} {incr i} { 
      sqlite3 db$i test.db 
      execsql { SELECT * FROM t1 } db$i
    }
    for {set i 0} {$i < 255} {incr i} { 
      set rc [vfs_shmlock db$i main shared lock 4 1]
      if {$rc != "SQLITE_OK"} { error $rc }
    }

    vfs_shmlock db255 main shared lock 4 1
  } {SQLITE_BUSY}

  do_test 2.1 { vfs_shmlock db255 main exclusive lock   4 1 } SQLITE_BUSY
  do_test 2.2 { vfs_shmlock db0   main shared    unlock 4 1 } SQLITE_OK
  do_test 2.3 { vfs_shmlock db255 main shared    lock   4 1 } SQLITE_OK
  do_test 2.4 { vfs_shmlock db255 main shared    unlock 4 1 } SQLITE_OK
  do_test 2.5 { vfs_shmlock db255 main exclusive lock   4 1 } SQLITE_BUSY

  do_test 2.6 {
    for {set i 1} {$i < 255} {incr i} { 
      set rc [vfs_shmlock db255 main exclusive lock 4 1]
      if {$rc != "SQLITE_BUSY"} { error $rc }
      set rc [vfs_shmlock db$i main shared unlock 4 1]
      if {$rc != "SQLITE_OK"} { error $rc }
    }

    vfs_shmlock db255 main exclusive lock 4 1
  } {SQLITE_OK}

  vfs_shmlock db255 main exclusive unlock 4 1

  for {set i 0} {$i < 256} {incr i} {
    db$i close
  }
}

sqlite3 db0 test.db
sqlite3 db1 test.db
do_test 3.1 { execsql { SELECT * FROM t1 } db0 } {1 2}
do_test 3.2 { execsql { SELECT * FROM t1 } db1 } {1 2}

set L(0) {n n n n n n n n}
set L(1) {n n n n n n n n}
proc random_lock_test {idx} {
  global L
  set iSlot [expr int(rand()*8)]
  if {[expr int(rand()*2)]} {
    # Unlock operation
    if {[lindex $L($idx) $iSlot]!="n"} {
      vfs_shmlock db$idx main [lindex $L($idx) $iSlot] unlock $iSlot 1
      lset L($idx) $iSlot n
    }
  } else {
    # Lock operation
    if {[lindex $L($idx) $iSlot]=="n"} {
      set locktype [lindex {e s} [expr int(rand()*2)]]
      set n 1
      if {$locktype=="e"} {
        for {set l $iSlot} {$l<8 && [lindex $L($idx) $l]=="n"} {incr l} {}
        set n [expr int(rand()*($l-$iSlot))+1]
        # puts "iSlot=$iSlot l=$l L=$L($idx)"
        # puts "$iSlot $n"
      }
      set res [vfs_shmlock db$idx main $locktype lock $iSlot $n]

      set bBusy 0
      for {set i $iSlot} {$i<($iSlot+$n)} {incr i} {
        set other [lindex $L([expr ($idx+1)%2]) $i]
        if {($other!="n" && $locktype=="e")||($other=="e" && $locktype=="s")} {
          if {$res != "SQLITE_BUSY"} { error "BUSY not detected" }
          set bBusy 1
          break
        } 
      }

      if {$bBusy==0} {
        if {$res != "SQLITE_OK"} { error "BUSY false-positive" }
        for {set i $iSlot} {$i<($iSlot+$n)} {incr i} {
          lset L($idx) $i $locktype
        }
      }
    }
  }
}

set nStep 100000
for {set i 0} {$i < $nStep} {incr i} {
  random_lock_test 0
  random_lock_test 1
}

db0 close
db1 close

finish_test

#
#   3. Using connection 1, checkpoint the database. Make sure all
#      the data is present and the database is not corrupt.
#
# At one point, SQLite was failing to grow the mapping of the wal-index
# file in step 3 and the checkpoint was corrupting the database file.
#
if {[permutation]!="unix-excl"} {
  do_test wal-20.1 {
    catch {db close}
    forcedelete test.db test.db-wal test.db-journal
    sqlite3 db test.db
    execsql {
      PRAGMA journal_mode = WAL;
      CREATE TABLE t1(x);
      INSERT INTO t1 VALUES(randomblob(900));
      SELECT count(*) FROM t1;
    }
  } {wal 1}
  do_test wal-20.2 {
    set ::buddy [launch_testfixture]
    testfixture $::buddy {
      sqlite3 db test.db
      db transaction { db eval {
        PRAGMA wal_autocheckpoint = 0;
        INSERT INTO t1 SELECT randomblob(900) FROM t1;       /* 2 */
        INSERT INTO t1 SELECT randomblob(900) FROM t1;       /* 4 */
        INSERT INTO t1 SELECT randomblob(900) FROM t1;       /* 8 */
        INSERT INTO t1 SELECT randomblob(900) FROM t1;       /* 16 */
        INSERT INTO t1 SELECT randomblob(900) FROM t1;       /* 32 */
        INSERT INTO t1 SELECT randomblob(900) FROM t1;       /* 64 */
        INSERT INTO t1 SELECT randomblob(900) FROM t1;       /* 128 */
        INSERT INTO t1 SELECT randomblob(900) FROM t1;       /* 256 */
        INSERT INTO t1 SELECT randomblob(900) FROM t1;       /* 512 */
        INSERT INTO t1 SELECT randomblob(900) FROM t1;       /* 1024 */
        INSERT INTO t1 SELECT randomblob(900) FROM t1;       /* 2048 */
        INSERT INTO t1 SELECT randomblob(900) FROM t1;       /* 4096 */
        INSERT INTO t1 SELECT randomblob(900) FROM t1;       /* 8192 */
        INSERT INTO t1 SELECT randomblob(900) FROM t1;       /* 16384 */
      } }
    }
  } {0}
  do_test wal-20.3 {
    close $::buddy
    execsql { PRAGMA wal_checkpoint }
    execsql { SELECT count(*) FROM t1 }
  } {16384}
  do_test wal-20.4 {
    db close
    sqlite3 db test.db
    execsql { SELECT count(*) FROM t1 }
  } {16384}
  integrity_check wal-20.5
}

catch { db2 close }
catch { db close }

do_test wal-21.1 {
  faultsim_delete_and_reopen
  execsql {