SQLite

*/
static int posixFchown(int fd, uid_t uid, gid_t gid){
  return geteuid() ? 0 : fchown(fd,uid,gid);
}

/* Forward reference */
static int openDirectory(const char*, int*);
static int unixGetpagesize(void);

/*
** Many system calls are accessed through pointer-to-functions so that
** they may be overridden at runtime to facilitate fault injection during
** testing and sandboxing.  The following array holds the names and pointers
** to all overrideable system calls.
*/

#if HAVE_MREMAP
  { "mremap",       (sqlite3_syscall_ptr)mremap,          0 },
#else
  { "mremap",       (sqlite3_syscall_ptr)0,               0 },
#endif
#define osMremap ((void*(*)(void*,size_t,size_t,int,...))aSyscall[23].pCurrent)
#endif

  { "getpagesize",  (sqlite3_syscall_ptr)unixGetpagesize, 0 },
#define osGetpagesize ((int(*)(void))aSyscall[24].pCurrent)

}; /* End of the overrideable system calls */

/*
** This is the xSetSystemCall() method of sqlite3_vfs for all of the
** "unix" VFSes.  Return SQLITE_OK opon successfully updating the
** system call pointer, or SQLITE_NOTFOUND if there is no configurable

#endif

  return rc;        
}

/*
** Return the system page size.
**
** This function should not be called directly by other code in this file. 
** Instead, it should be called via macro osGetpagesize().
*/
static int unixGetpagesize(void){
#if defined(_BSD_SOURCE)
  return getpagesize();
#else
  return (int)sysconf(_SC_PAGESIZE);
#endif
}

/*
** Return the minimum number of 32KB shm regions that should be mapped at
** a time, assuming that each mapping must be an integer multiple of the
** current system page-size.
**
** Usually, this is 1. The exception seems to be systems that are configured
** to use 64KB pages - in this case each mapping must cover at least two
** shm regions.
*/
static int unixShmRegionPerMap(void){
  int shmsz = 32*1024;            /* SHM region size */
  int pgsz = osGetpagesize();   /* System page size */
  assert( ((pgsz-1)&pgsz)==0 );   /* Page size must be a power of 2 */
  if( pgsz<shmsz ) return 1;
  return pgsz/shmsz;
}

/*
** Purge the unixShmNodeList list of all entries with unixShmNode.nRef==0.

  if( (pFd->ctrlFlags & UNIXFILE_RDONLY)==0 ) flags |= PROT_WRITE;

  if( pOrig ){
#if HAVE_MREMAP
    i64 nReuse = pFd->mmapSize;
#else
    const int szSyspage = osGetpagesize();
    i64 nReuse = (pFd->mmapSize & ~(szSyspage-1));
#endif
    u8 *pReq = &pOrig[nReuse];

    /* Unmap any pages of the existing mapping that cannot be reused. */
    if( nReuse!=nOrig ){
      osMunmap(pReq, nOrig-nReuse);

    UNIXVFS("unix-proxy",    proxyIoFinder ),
#endif
  };
  unsigned int i;          /* Loop counter */

  /* Double-check that the aSyscall[] array has been constructed
  ** correctly.  See ticket [bb3a86e890c8e96ab] */
  assert( ArraySize(aSyscall)==25 );

  /* Register all VFSes defined in the aVfs[] array */
  for(i=0; i<(sizeof(aVfs)/sizeof(sqlite3_vfs)); i++){
    sqlite3_vfs_register(&aVfs[i], i==0);
  }
  return SQLITE_OK; 
}

**
**   test_syscall exists SYSTEM-CALL
**     Return true if the named system call exists. Or false otherwise.
**
**   test_syscall list
**     Return a list of all system calls. The list is constructed using
**     the xNextSystemCall() VFS method.
**
**   test_syscall pagesize PGSZ
**     If PGSZ is a power of two greater than 256, install a wrapper around
**     OS function getpagesize() that reports the system page size as PGSZ.
**     Or, if PGSZ is less than zero, remove any wrapper already installed.
*/

#include "sqliteInt.h"
#include "sqlite3.h"
#include "tcl.h"
#include <stdlib.h>
#include <string.h>

#include <sys/types.h>
#include <errno.h>

static struct TestSyscallGlobal {
  int bPersist;                   /* 1 for persistent errors, 0 for transient */
  int nCount;                     /* Fail after this many more calls */
  int nFail;                      /* Number of failures that have occurred */
  int pgsz;
  sqlite3_syscall_ptr orig_getpagesize;
} gSyscall = { 0, 0, 0, 0, 0 };

static int ts_open(const char *, int, int);
static int ts_close(int fd);
static int ts_access(const char *zPath, int mode);
static char *ts_getcwd(char *zPath, size_t nPath);
static int ts_stat(const char *zPath, struct stat *p);
static int ts_fstat(int fd, struct stat *p);

    return TCL_ERROR;
  }

  pVfs = sqlite3_vfs_find(0);
  Tcl_SetObjResult(interp, Tcl_NewStringObj(pVfs->zName, -1));
  return TCL_OK;
}

static int ts_getpagesize(void){
  return gSyscall.pgsz;
}

static int test_syscall_pagesize(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  sqlite3_vfs *pVfs = sqlite3_vfs_find(0);
  int pgsz;
  if( objc!=3 ){
    Tcl_WrongNumArgs(interp, 2, objv, "PGSZ");
    return TCL_ERROR;
  }
  if( Tcl_GetIntFromObj(interp, objv[2], &pgsz) ){
    return TCL_ERROR;
  }

  if( pgsz<0 ){
    if( gSyscall.orig_getpagesize ){
      pVfs->xSetSystemCall(pVfs, "getpagesize", gSyscall.orig_getpagesize);
    }
  }else{
    if( pgsz<512 || (pgsz & (pgsz-1)) ){
      Tcl_AppendResult(interp, "pgsz out of range", 0);
      return TCL_ERROR;
    }
    gSyscall.orig_getpagesize = pVfs->xGetSystemCall(pVfs, "getpagesize");
    gSyscall.pgsz = pgsz;
    pVfs->xSetSystemCall(
        pVfs, "getpagesize", (sqlite3_syscall_ptr)ts_getpagesize
    );
  }

  return TCL_OK;
}

static int test_syscall(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  struct SyscallCmd {
    const char *zName;
    Tcl_ObjCmdProc *xCmd;
  } aCmd[] = {
    { "fault",      test_syscall_fault },
    { "install",    test_syscall_install },
    { "uninstall",  test_syscall_uninstall },
    { "reset",      test_syscall_reset },
    { "errno",      test_syscall_errno },
    { "exists",     test_syscall_exists },
    { "list",       test_syscall_list },
    { "defaultvfs", test_syscall_defaultvfs },
    { "pagesize",   test_syscall_pagesize },
    { 0, 0 }
  };
  int iCmd;
  int rc;

  if( objc<2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "SUB-COMMAND ...");

# Tests for the xNextSystemCall method.
#
foreach s {
    open close access getcwd stat fstat ftruncate
    fcntl read pread write pwrite fchmod fallocate
    pread64 pwrite64 unlink openDirectory mkdir rmdir 
    statvfs fchown umask mmap munmap mremap
    getpagesize
} {
  if {[test_syscall exists $s]} {lappend syscall_list $s}
}
do_test 3.1 { lsort [test_syscall list] } [lsort $syscall_list]

#-------------------------------------------------------------------------
# This test verifies that if a call to open() fails and errno is set to

# 2010 April 13
#
# 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 file is testing the operation of the library in
# "PRAGMA journal_mode=WAL" mode.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
set testprefix wal64k

ifcapable !wal {finish_test ; return }

db close
test_syscall pagesize 65536
sqlite3 db test.db

do_execsql_test 1.0 { 
  PRAGMA journal_mode = WAL;
  CREATE TABLE t1(x);
  CREATE INDEX i1 ON t1(x);
} {wal}
do_test 1.1 { file size test.db-shm } {65536}

do_test 1.2 {
  execsql BEGIN
  while {[file size test.db-shm]==65536} {
    execsql { INSERT INTO t1 VALUES( randstr(900,1100) ) }
  }
  execsql COMMIT
  file size test.db-shm
} {131072}

integrity_check 1.3

db close
test_syscall pagesize -1
finish_test