SQLite

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
******************************************************************************
**
** This file contains code that is specific to Unix systems.
**
** $Id: os_unix.c,v 1.220 2008/11/21 22:21:50 drh Exp $
*/
#include "sqliteInt.h"
#if SQLITE_OS_UNIX              /* This file is used on unix only */

/*
** If SQLITE_ENABLE_LOCKING_STYLE is defined and is non-zero, then several
** alternative locking implementations are provided:

  int oflags;                      /* The flags specified at open */
#endif
#if SQLITE_THREADSAFE
  pthread_t tid;                   /* The thread that "owns" this unixFile */
#endif
#if OS_VXWORKS
  int isDelete;                    /* Delete on close if true */
  struct vxworksFileId *pId;       /* Unique file ID */
#endif
#ifdef SQLITE_TEST
  /* In test mode, increase the size of this structure a bit so that 
  ** it is larger than the struct CrashFile defined in test6.c.
  */
  char aPadding[32];
#endif

*/
#if SQLITE_THREADSAFE
#define threadid pthread_self()
#else
#define threadid 0
#endif


/*
** Helper functions to obtain and relinquish the global mutex.
*/
static void unixEnterMutex(void){
  sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));
}
static void unixLeaveMutex(void){
  sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));
}

/************************************************************************
*********** Posix Advisory Locking And Thread Interaction ***************
*************************************************************************
**
** Here is the dirt on POSIX advisory locks:  ANSI STD 1003.1 (1996)
** section 6.5.2.2 lines 483 through 490 specify that when a process

/*
** An instance of the following structure serves as the key used
** to locate a particular unixOpenCnt structure given its inode.  This
** is the same as the unixLockKey except that the thread ID is omitted.
*/
struct unixFileId {
  dev_t dev;                  /* Device number */
#if OS_VXWORKS
  struct vxworksFileId *pId;  /* Unique file ID for vxworks. */
#else
  ino_t ino;                  /* Inode number */
#endif
};

/*
** An instance of the following structure serves as the key used
** to locate a particular unixLockInfo structure given its inode.
**

      return SQLITE_IOERR;
    }
  }

  memset(&lockKey, 0, sizeof(lockKey));
  lockKey.fid.dev = statbuf.st_dev;
#if OS_VXWORKS



  lockKey.fid.pId = pFile->pId;
#else
  lockKey.fid.ino = statbuf.st_ino;
#endif
#if SQLITE_THREADSAFE
  if( threadsOverrideEachOthersLocks<0 ){
    testThreadLockingBehavior(fd);
  }

exit_findlockinfo:
  return rc;
}
/**************************************************************************
******************** End of the posix lock work-around ********************
**************************************************************************/

/**************************************************************************
**************** Begin Unique File ID Utility Used By VxWorks *************
***************************************************************************
**
** The inode numbers of files are meaningless in VxWorks.  Inodes cannot
** be used to find a unique identifier for a file.   A unique file id
** must be based on the canonical filename.
**
** A pointer to an instance of the following structure can be used as a
** unique file ID in VxWorks.  Each instance of this structure contains
** a copy of the canonical filename.  There is also a reference count.  
** The structure is reclaimed when the number of pointers to it drops to
** zero.
**
** There are never very many files open at one time and lookups are not
** a performance-critical path, so it is sufficient to put these
** structures on a linked list.
*/
struct vxworksFileId {
  struct vxworksFileId *pNext;  /* Next in a list of them all */
  int nRef;                     /* Number of references to this one */
  int nName;                    /* Length of the zCanonicalName[] string */
  char *zCanonicalName;         /* Canonical filename */
};

#if OS_VXWORKS
/* 
** All unique filesname are held on a linked list headed by this
** variable:
*/
static struct vxworksFileId *vxworksFileList = 0;
#endif

#if OS_VXWORKS
/*
** Simplify a filename into its canonical form
** by making the following changes:


**
**  * removing any trailing and duplicate /
**  * removing /./
**  * removing /A/../
**
** Changes are made in-place.  Return the new name length.
**
** The original filename is in z[0..n-1].  Return the number of
** characters in the simplified name.
*/
static int vxworksSimplifyName(char *z, int n){
  int i, j;
  while( n>1 && z[n-1]=='/' ){ n--; }
  for(i=j=0; i<n; i++){
    if( z[i]=='/' ){
      if( z[i+1]=='/' ) continue;
      if( z[i+1]=='.' && i+2<n && z[i+2]=='/' ){
        i += 1;
        continue;
      }
      if( z[i+1]=='.' && i+3<n && z[i+2]=='.' && z[i+3]=='/' ){
        while( j>0 && z[j-1]!='/' ){ j--; }
        if( j>0 ){ j--; }
        i += 2;
        continue;
      }
    }
    z[j++] = z[i];
  }
  z[j] = 0;
  return j;
}
#endif /* OS_VXWORKS */

#if OS_VXWORKS
/*
** Find a unique file ID for the given absolute pathname.  Return
** a pointer to the vxworksFileId object.  This pointer is the unique
** file ID.
**
** The nRef field of the vxworksFileId object is incremented before
** the object is returned.  A new vxworksFileId object is created
** and added to the global list if necessary.
**
** If a memory allocation error occurs, return NULL.
*/

static struct vxworksFileId *vxworksFindFileId(const char *zAbsoluteName){

  struct vxworksFileId *pNew;         /* search key and new file ID */



  struct vxworksFileId *pCandidate;   /* For looping over existing file IDs */

  int n;                              /* Length of zAbsoluteName string */










  assert( zAbsoluteName[0]=='/' );
  n = strlen(zAbsoluteName);
  pNew = sqlite3_malloc( sizeof(*pNew) + (n+1) );
  if( pNew==0 ) return 0;


  pNew->zCanonicalName = (char*)&pNew[1];
  memcpy(pNew->zCanonicalName, zAbsoluteName, n+1);
  n = vxworksSimplifyName(pNew->zCanonicalName, n);

  /* Search for an existing entry that matching the canonical name.
  ** If found, increment the reference count and return a pointer to
  ** the existing file ID.
  */
  unixEnterMutex();
  for(pCandidate=vxworksFileList; pCandidate; pCandidate=pCandidate->pNext){
    if( pCandidate->nName==n 
     && memcmp(pCandidate->zCanonicalName, pNew->zCanonicalName, n)==0
    ){
       sqlite3_free(pNew);
       pCandidate->nRef++;

       unixLeaveMutex();
       return pCandidate;
    }



  }









  /* No match was found.  We will make a new file ID */
  pNew->nRef = 1;


  pNew->nName = n;



  pNew->pNext = vxworksFileList;

  vxworksFileList = pNew;

  unixLeaveMutex();
  return pNew;
}
#endif /* OS_VXWORKS */









#if OS_VXWORKS
/*
** Decrement the reference count on a vxworksFileId object.  Free
** the object when the reference count reaches zero.
*/
static void vxworksReleaseFileId(struct vxworksFileId *pId){
  unixEnterMutex();
  assert( pId->nRef>0 );
  pId->nRef--;
  if( pId->nRef==0 ){
    struct vxworksFileId **pp;


    for(pp=&vxworksFileList; *pp && *pp!=pId; pp = &((*pp)->pNext)){}
    assert( *pp==pId );
    *pp = pId->pNext;
    sqlite3_free(pId);

  }



  unixLeaveMutex();

}
#endif /* OS_VXWORKS */
/**************************************************************************
************** End of Unique File ID Utility Used By VxWorks **************
**************************************************************************/

#ifdef SQLITE_TEST
/* simulate multiple hosts by creating unique hostid file paths */
int sqlite3_hostid_num = 0;
#endif

/*

/*
** Only set the lastErrno if the error code is a real error and not 
** a normal expected return code of SQLITE_BUSY or SQLITE_OK
*/
#define IS_LOCK_ERROR(x)  ((x != SQLITE_OK) && (x != SQLITE_BUSY))











#ifdef SQLITE_LOCK_TRACE
/*
** Print out information about all locking operations.
**
** This routine is used for troubleshooting locks on multithreaded
** platforms.  Enable by compiling with the -DSQLITE_LOCK_TRACE
** command-line option on the compiler.  This code is normally

      int err = close(pFile->h);
      if( err ){
        pFile->lastErrno = errno;
        return SQLITE_IOERR_CLOSE;
      }
    }
#if OS_VXWORKS
    if( pFile->pId ){
      if( pFile->isDelete ){
         unlink(pFile->pId->zCanonicalName);
      }
      vxworksReleaseFileId(pFile->pId);

      pFile->pId = 0;










    }
#endif
    OSTRACE2("CLOSE   %-3d\n", pFile->h);
    OpenCounter(-1);
    memset(pFile, 0, sizeof(unixFile));
  }
  return SQLITE_OK;

  OSTRACE3("OPEN    %-3d %s\n", h, zFilename);    
  pNew->h = h;
  pNew->dirfd = dirfd;
  SET_THREADID(pNew);

#if OS_VXWORKS


  pNew->pId = vxworksFindFileId(zFilename);

  if( pNew->pId==0 ){

    noLock = 1;

















    rc = SQLITE_NOMEM;







  }
#endif

  if( noLock ){
    eLockingStyle = LOCKING_STYLE_NONE;
  }else{
    eLockingStyle = detectLockingStyle(pVfs, zFilename, h);

       ** included in the namedsemLockingContext
       */
      unixEnterMutex();
      rc = findLockInfo(pNew, &pNew->pLock, &pNew->pOpen);
      if( (rc==SQLITE_OK) && (pNew->pOpen->pSem==NULL) ){
        char *zSemName = pNew->pOpen->aSemName;
        int n;
        sqlite3_snprintf(MAX_PATHNAME, zSemName, "%s.sem",
                         pNew->pId->zCanonicalName);
        for( n=0; zSemName[n]; n++ )
          if( zSemName[n]=='/' ) zSemName[n] = '_';
        pNew->pOpen->pSem = sem_open(zSemName, O_CREAT, 0666, 1);
        if( pNew->pOpen->pSem == SEM_FAILED ){
          rc = SQLITE_NOMEM;
          pNew->pOpen->aSemName[0] = '\0';
        }

  ** current working directly has been unlinked.
  */
  SimulateIOError( return SQLITE_ERROR );

  assert( pVfs->mxPathname==MAX_PATHNAME );
  UNUSED_PARAMETER(pVfs);













  zOut[nOut-1] = '\0';
  if( zPath[0]=='/' ){
    sqlite3_snprintf(nOut, zOut, "%s", zPath);
  }else{
    int nCwd;
    if( getcwd(zOut, nOut-1)==0 ){
      return SQLITE_CANTOPEN;
    }
    nCwd = strlen(zOut);
    sqlite3_snprintf(nOut-nCwd, &zOut[nCwd], "/%s", zPath);
  }
  return SQLITE_OK;



























}


#ifndef SQLITE_OMIT_LOAD_EXTENSION
/*
** Interfaces for opening a shared library, finding entry points
** within the shared library, and closing the shared library.

    UNIXVFS("unix-namedsem",LOCKING_STYLE_NAMEDSEM),
    UNIXVFS("unix-proxy",   LOCKING_STYLE_PROXY)
  };
  for(i=0; i<(sizeof(aVfs)/sizeof(sqlite3_vfs)); i++){
    sqlite3_vfs_register(&aVfs[i], 0);
  }
#endif



  sqlite3_vfs_register(&unixVfs, 1);
  return SQLITE_OK; 
}

/*
** Shutdown the operating system interface. This is a no-op for unix.
*/
int sqlite3_os_end(void){ 
  return SQLITE_OK; 
}
 
#endif /* SQLITE_OS_UNIX */

#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this script testing the ability of SQLite to handle database
# files larger than 4GB.
#
# $Id: bigfile.test,v 1.11 2008/11/21 22:21:51 drh Exp $
#

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

# If SQLITE_DISABLE_LFS is defined, omit this file.
ifcapable !lfs {

} $::MAGIC_SUM

# Try to create a large file - a file that is larger than 2^32 bytes.
# If this fails, it means that the system being tested does not support
# large files.  So skip all of the remaining tests in this file.
#
db close
if {[catch {fake_big_file 4096 [pwd]/test.db} msg]} {
  puts "**** Unable to create a file larger than 4096 MB. *****"
  puts "$msg"
  finish_test
  return
}

do_test bigfile-1.2 {

do_test bigfile-1.5 {
  execsql {
    SELECT md5sum(x) FROM t2;
  }
} $::MAGIC_SUM

db close
if {[catch {fake_big_file 8192 [pwd]/test.db}]} {
  puts "**** Unable to create a file larger than 8192 MB. *****"
  finish_test
  return
}

do_test bigfile-1.6 {
  sqlite3 db test.db

do_test bigfile-1.10 {
  execsql {
    SELECT md5sum(x) FROM t3;
  }
} $::MAGIC_SUM

db close
if {[catch {fake_big_file 16384 [pwd]/test.db}]} {
  puts "**** Unable to create a file larger than 16384 MB. *****"
  finish_test
  return
}

do_test bigfile-1.11 {
  sqlite3 db test.db

# 2001 September 15
#
# 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 database locks.
#
# $Id: lock.test,v 1.34 2008/11/21 22:21:51 drh Exp $


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

# Create an alternative connection to the database
#
do_test lock-1.0 {
  # Give a complex pathnme to stress the path simplification logic in
  # the vxworks driver.
  file mkdir tempdir/t1/t2
  sqlite3 db2 ./tempdir/../tempdir/t1/.//t2/../../..//test.db
  set dummy {}
} {}
do_test lock-1.1 {
  execsql {SELECT name FROM sqlite_master WHERE type='table' ORDER BY name}
} {}
do_test lock-1.2 {
  execsql {SELECT name FROM sqlite_master WHERE type='table' ORDER BY name} db2

#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this script is database locks and the operation of the
# DEFERRED, IMMEDIATE, and EXCLUSIVE keywords as modifiers to the
# BEGIN command.
#
# $Id: lock3.test,v 1.2 2008/11/21 22:21:51 drh Exp $


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

# Establish two connections to the same database.  Put some
# sample data into the database.
#
do_test lock3-1.1 {
  file mkdir tempdir/t1/t2/t3
  sqlite3 db2 ./tempdir/t1//t2/./t3//./../..//./../../tempdir/..//test.db//
  execsql {
    CREATE TABLE t1(a);
    INSERT INTO t1 VALUES(1);
  }
  execsql {
    SELECT * FROM t1
  } db2