[sql] Import SQLite 3.17.0.

third_party/sqlite/src/src/os_unix.c

Index: third_party/sqlite/src/src/os_unix.c
diff --git a/third_party/sqlite/src/src/os_unix.c b/third_party/sqlite/src/src/os_unix.c
index e1228e3e5590d5b39b012209a72e2a8488f0e39b..60981af7e738e70bc6d827683c4ef0ae41e2e091 100644
--- a/third_party/sqlite/src/src/os_unix.c
+++ b/third_party/sqlite/src/src/os_unix.c
@@ -71,6 +71,19 @@
 #  endif
 #endif
 
+/* Use pread() and pwrite() if they are available */
+#if defined(__APPLE__)
+# define HAVE_PREAD 1
+# define HAVE_PWRITE 1
+#endif
+#if defined(HAVE_PREAD64) && defined(HAVE_PWRITE64)
+# undef USE_PREAD
+# define USE_PREAD64 1
+#elif defined(HAVE_PREAD) && defined(HAVE_PWRITE)
+# undef USE_PREAD64
+# define USE_PREAD 1
+#endif
+
 /*
 ** standard include files.
 */
@@ -149,6 +162,11 @@
 */
 #define MAX_PATHNAME 512
 
+/*
+** Maximum supported symbolic links
+*/
+#define SQLITE_MAX_SYMLINKS 100
+
 /* Always cast the getpid() return type for compatibility with
 ** kernel modules in VxWorks. */
 #define osGetpid(X) (pid_t)getpid()
@@ -387,7 +405,7 @@ static struct unix_syscall {
 #else
   { "pread64",      (sqlite3_syscall_ptr)0,          0  },
 #endif
-#define osPread64   ((ssize_t(*)(int,void*,size_t,off_t))aSyscall[10].pCurrent)
+#define osPread64 ((ssize_t(*)(int,void*,size_t,off64_t))aSyscall[10].pCurrent)
 
   { "write",        (sqlite3_syscall_ptr)write,      0  },
 #define osWrite     ((ssize_t(*)(int,const void*,size_t))aSyscall[11].pCurrent)
@@ -405,7 +423,7 @@ static struct unix_syscall {
 #else
   { "pwrite64",     (sqlite3_syscall_ptr)0,          0  },
 #endif
-#define osPwrite64  ((ssize_t(*)(int,const void*,size_t,off_t))\
+#define osPwrite64  ((ssize_t(*)(int,const void*,size_t,off64_t))\
                     aSyscall[13].pCurrent)
 
   { "fchmod",       (sqlite3_syscall_ptr)fchmod,          0  },
@@ -430,33 +448,57 @@ static struct unix_syscall {
   { "rmdir",        (sqlite3_syscall_ptr)rmdir,           0 },
 #define osRmdir     ((int(*)(const char*))aSyscall[19].pCurrent)
 
+#if defined(HAVE_FCHOWN)
   { "fchown",       (sqlite3_syscall_ptr)fchown,          0 },
+#else
+  { "fchown",       (sqlite3_syscall_ptr)0,               0 },
+#endif
 #define osFchown    ((int(*)(int,uid_t,gid_t))aSyscall[20].pCurrent)
 
   { "geteuid",      (sqlite3_syscall_ptr)geteuid,         0 },
 #define osGeteuid   ((uid_t(*)(void))aSyscall[21].pCurrent)
 
 #if !defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0
-  { "mmap",       (sqlite3_syscall_ptr)mmap,     0 },
+  { "mmap",         (sqlite3_syscall_ptr)mmap,            0 },
+#else
+  { "mmap",         (sqlite3_syscall_ptr)0,               0 },
+#endif
 #define osMmap ((void*(*)(void*,size_t,int,int,int,off_t))aSyscall[22].pCurrent)
 
+#if !defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0
   { "munmap",       (sqlite3_syscall_ptr)munmap,          0 },
+#else
+  { "munmap",       (sqlite3_syscall_ptr)0,               0 },
+#endif
 #define osMunmap ((void*(*)(void*,size_t))aSyscall[23].pCurrent)
 
-#if HAVE_MREMAP
+#if HAVE_MREMAP && (!defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0)
   { "mremap",       (sqlite3_syscall_ptr)mremap,          0 },
 #else
   { "mremap",       (sqlite3_syscall_ptr)0,               0 },
 #endif
 #define osMremap ((void*(*)(void*,size_t,size_t,int,...))aSyscall[24].pCurrent)
 
+#if !defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0
   { "getpagesize",  (sqlite3_syscall_ptr)unixGetpagesize, 0 },
+#else
+  { "getpagesize",  (sqlite3_syscall_ptr)0,               0 },
+#endif
 #define osGetpagesize ((int(*)(void))aSyscall[25].pCurrent)
 
+#if defined(HAVE_READLINK)
   { "readlink",     (sqlite3_syscall_ptr)readlink,        0 },
+#else
+  { "readlink",     (sqlite3_syscall_ptr)0,               0 },
+#endif
 #define osReadlink ((ssize_t(*)(const char*,char*,size_t))aSyscall[26].pCurrent)
 
+#if defined(HAVE_LSTAT)
+  { "lstat",         (sqlite3_syscall_ptr)lstat,          0 },
+#else
+  { "lstat",         (sqlite3_syscall_ptr)0,              0 },
 #endif
+#define osLstat      ((int(*)(const char*,struct stat*))aSyscall[27].pCurrent)
 
 }; /* End of the overrideable system calls */
 
@@ -467,10 +509,10 @@ static struct unix_syscall {
 ** we are not running as root.
 */
 static int robustFchown(int fd, uid_t uid, gid_t gid){
-#if OS_VXWORKS
-  return 0;
-#else
+#if defined(HAVE_FCHOWN)
   return osGeteuid() ? 0 : osFchown(fd,uid,gid);
+#else
+  return 0;
 #endif
 }
 
@@ -1019,7 +1061,14 @@ struct unixFileId {
 #if OS_VXWORKS
   struct vxworksFileId *pId;  /* Unique file ID for vxworks. */
 #else
-  ino_t ino;                  /* Inode number */
+  /* We are told that some versions of Android contain a bug that
+  ** sizes ino_t at only 32-bits instead of 64-bits. (See
+  ** https://android-review.googlesource.com/#/c/115351/3/dist/sqlite3.c)
+  ** To work around this, always allocate 64-bits for the inode number.  
+  ** On small machines that only have 32-bit inodes, this wastes 4 bytes,
+  ** but that should not be a big deal. */
+  /* WAS:  ino_t ino;   */
+  u64 ino;                   /* Inode number */
 #endif
 };
 
@@ -1264,7 +1313,7 @@ static int findInodeInfo(
 #if OS_VXWORKS
   fileId.pId = pFile->pId;
 #else
-  fileId.ino = statbuf.st_ino;
+  fileId.ino = (u64)statbuf.st_ino;
 #endif
   pInode = inodeList;
   while( pInode && memcmp(&fileId, &pInode->fileId, sizeof(fileId)) ){
@@ -1273,7 +1322,7 @@ static int findInodeInfo(
   if( pInode==0 ){
     pInode = sqlite3_malloc64( sizeof(*pInode) );
     if( pInode==0 ){
-      return SQLITE_NOMEM;
+      return SQLITE_NOMEM_BKPT;
     }
     memset(pInode, 0, sizeof(*pInode));
     memcpy(&pInode->fileId, &fileId, sizeof(fileId));
@@ -1304,7 +1353,8 @@ static int fileHasMoved(unixFile *pFile){
   return 0;
 
   return pFile->pInode!=0 &&
-      (osStat(pFile->zPath, &buf)!=0 || buf.st_ino!=pFile->pInode->fileId.ino);
+      (osStat(pFile->zPath, &buf)!=0 
+         || (u64)buf.st_ino!=pFile->pInode->fileId.ino);
 #endif
 }
 
@@ -1321,12 +1371,16 @@ static int fileHasMoved(unixFile *pFile){
 static void verifyDbFile(unixFile *pFile){
   struct stat buf;
   int rc;
+
+  /* These verifications occurs for the main database only */
+  if( pFile->ctrlFlags & UNIXFILE_NOLOCK ) return;
+
   rc = osFstat(pFile->h, &buf);
   if( rc!=0 ){
     sqlite3_log(SQLITE_WARNING, "cannot fstat db file %s", pFile->zPath);
     return;
   }
-  if( buf.st_nlink==0 && (pFile->ctrlFlags & UNIXFILE_DELETE)==0 ){
+  if( buf.st_nlink==0 ){
     sqlite3_log(SQLITE_WARNING, "file unlinked while open: %s", pFile->zPath);
     return;
   }
@@ -1462,7 +1516,7 @@ static int unixLock(sqlite3_file *id, int eFileLock){
   ** lock transitions in terms of the POSIX advisory shared and exclusive
   ** lock primitives (called read-locks and write-locks below, to avoid
   ** confusion with SQLite lock names). The algorithms are complicated
-  ** slightly in order to be compatible with windows systems simultaneously
+  ** slightly in order to be compatible with Windows95 systems simultaneously
   ** accessing the same database file, in case that is ever required.
   **
   ** Symbols defined in os.h indentify the 'pending byte' and the 'reserved
@@ -1470,8 +1524,14 @@ static int unixLock(sqlite3_file *id, int eFileLock){
   ** range', a range of 510 bytes at a well known offset.
   **
   ** To obtain a SHARED lock, a read-lock is obtained on the 'pending
-  ** byte'.  If this is successful, a random byte from the 'shared byte
-  ** range' is read-locked and the lock on the 'pending byte' released.
+  ** byte'.  If this is successful, 'shared byte range' is read-locked
+  ** and the lock on the 'pending byte' released.  (Legacy note:  When
+  ** SQLite was first developed, Windows95 systems were still very common,
+  ** and Widnows95 lacks a shared-lock capability.  So on Windows95, a
+  ** single randomly selected by from the 'shared byte range' is locked.
+  ** Windows95 is now pretty much extinct, but this work-around for the
+  ** lack of shared-locks on Windows95 lives on, for backwards
+  ** compatibility.)
   **
   ** A process may only obtain a RESERVED lock after it has a SHARED lock.
   ** A RESERVED lock is implemented by grabbing a write-lock on the
@@ -1490,11 +1550,6 @@ static int unixLock(sqlite3_file *id, int eFileLock){
   ** range'. Since all other locks require a read-lock on one of the bytes
   ** within this range, this ensures that no other locks are held on the
   ** database. 
-  **
-  ** The reason a single byte cannot be used instead of the 'shared byte
-  ** range' is that some versions of windows do not support read-locks. By
-  ** locking a random byte from a range, concurrent SHARED locks may exist
-  ** even if the locking primitive used is always a write-lock.
   */
   int rc = SQLITE_OK;
   unixFile *pFile = (unixFile*)id;
@@ -3141,7 +3196,7 @@ static int unixRead(
   );
 #endif
 
-#if defined(SQLITE_MMAP_READWRITE) && SQLITE_MAX_MMAP_SIZE>0
+#if SQLITE_MAX_MMAP_SIZE>0
   /* Deal with as much of this read request as possible by transfering
   ** data from the memory mapping using memcpy().  */
   if( offset<pFile->mmapSize ){
@@ -4199,7 +4254,7 @@ static int unixOpenSharedMemory(unixFile *pDbFd){
 
   /* Allocate space for the new unixShm object. */
   p = sqlite3_malloc64( sizeof(*p) );
-  if( p==0 ) return SQLITE_NOMEM;
+  if( p==0 ) return SQLITE_NOMEM_BKPT;
   memset(p, 0, sizeof(*p));
   assert( pDbFd->pShm==0 );
 
@@ -4231,7 +4286,7 @@ static int unixOpenSharedMemory(unixFile *pDbFd){
 #endif
     pShmNode = sqlite3_malloc64( sizeof(*pShmNode) + nShmFilename );
     if( pShmNode==0 ){
-      rc = SQLITE_NOMEM;
+      rc = SQLITE_NOMEM_BKPT;
       goto shm_open_err;
     }
     memset(pShmNode, 0, sizeof(*pShmNode)+nShmFilename);
@@ -4247,10 +4302,12 @@ static int unixOpenSharedMemory(unixFile *pDbFd){
     pShmNode->h = -1;
     pDbFd->pInode->pShmNode = pShmNode;
     pShmNode->pInode = pDbFd->pInode;
-    pShmNode->mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
-    if( pShmNode->mutex==0 ){
-      rc = SQLITE_NOMEM;
-      goto shm_open_err;
+    if( sqlite3GlobalConfig.bCoreMutex ){
+      pShmNode->mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
+      if( pShmNode->mutex==0 ){
+        rc = SQLITE_NOMEM_BKPT;
+        goto shm_open_err;
+      }
     }
 
     if( pInode->bProcessLock==0 ){
@@ -4422,7 +4479,7 @@ static int unixShmMap(
         pShmNode->apRegion, nReqRegion*sizeof(char *)
     );
     if( !apNew ){
-      rc = SQLITE_IOERR_NOMEM;
+      rc = SQLITE_IOERR_NOMEM_BKPT;
       goto shmpage_out;
     }
     pShmNode->apRegion = apNew;
@@ -4442,7 +4499,7 @@ static int unixShmMap(
       }else{
         pMem = sqlite3_malloc64(szRegion);
         if( pMem==0 ){
-          rc = SQLITE_NOMEM;
+          rc = SQLITE_NOMEM_BKPT;
           goto shmpage_out;
         }
         memset(pMem, 0, szRegion);
@@ -5220,7 +5277,7 @@ static int fillInUnixFile(
   pNew->pId = vxworksFindFileId(zFilename);
   if( pNew->pId==0 ){
     ctrlFlags |= UNIXFILE_NOLOCK;
-    rc = SQLITE_NOMEM;
+    rc = SQLITE_NOMEM_BKPT;
   }
 #endif
 
@@ -5276,7 +5333,7 @@ static int fillInUnixFile(
     afpLockingContext *pCtx;
     pNew->lockingContext = pCtx = sqlite3_malloc64( sizeof(*pCtx) );
     if( pCtx==0 ){
-      rc = SQLITE_NOMEM;
+      rc = SQLITE_NOMEM_BKPT;
     }else{
       /* NB: zFilename exists and remains valid until the file is closed
       ** according to requirement F11141.  So we do not need to make a
@@ -5306,7 +5363,7 @@ static int fillInUnixFile(
     nFilename = (int)strlen(zFilename) + 6;
     zLockFile = (char *)sqlite3_malloc64(nFilename);
     if( zLockFile==0 ){
-      rc = SQLITE_NOMEM;
+      rc = SQLITE_NOMEM_BKPT;
     }else{
       sqlite3_snprintf(nFilename, zLockFile, "%s" DOTLOCK_SUFFIX, zFilename);
     }
@@ -5329,7 +5386,7 @@ static int fillInUnixFile(
         if( zSemName[n]=='/' ) zSemName[n] = '_';
       pNew->pInode->pSem = sem_open(zSemName, O_CREAT, 0666, 1);
       if( pNew->pInode->pSem == SEM_FAILED ){
-        rc = SQLITE_NOMEM;
+        rc = SQLITE_NOMEM_BKPT;
         pNew->pInode->aSemName[0] = '\0';
       }
     }
@@ -5369,20 +5426,24 @@ static const char *unixTempFileDir(void){
      "/tmp",
      "."
   };
-  unsigned int i;
+  unsigned int i = 0;
   struct stat buf;
   const char *zDir = sqlite3_temp_directory;
 
   if( !azDirs[0] ) azDirs[0] = getenv("SQLITE_TMPDIR");
   if( !azDirs[1] ) azDirs[1] = getenv("TMPDIR");
-  for(i=0; i<sizeof(azDirs)/sizeof(azDirs[0]); zDir=azDirs[i++]){
-    if( zDir==0 ) continue;
-    if( osStat(zDir, &buf) ) continue;
-    if( !S_ISDIR(buf.st_mode) ) continue;
-    if( osAccess(zDir, 07) ) continue;
-    break;
-  }
-  return zDir;
+  while(1){
+    if( zDir!=0
+     && osStat(zDir, &buf)==0
+     && S_ISDIR(buf.st_mode)
+     && osAccess(zDir, 03)==0
+    ){
+      return zDir;
+    }
+    if( i>=sizeof(azDirs)/sizeof(azDirs[0]) ) break;
+    zDir = azDirs[i++];
+  }
+  return 0;
 }
 
 /*
@@ -5398,9 +5459,11 @@ static int unixGetTempname(int nBuf, char *zBuf){
   ** using the io-error infrastructure to test that SQLite handles this
   ** function failing. 
   */
+  zBuf[0] = 0;
   SimulateIOError( return SQLITE_IOERR );
 
   zDir = unixTempFileDir();
+  if( zDir==0 ) return SQLITE_IOERR_GETTEMPPATH;
   do{
     u64 r;
     sqlite3_randomness(sizeof(r), &r);
@@ -5463,7 +5526,7 @@ static UnixUnusedFd *findReusableFd(const char *zPath, int flags){
     unixEnterMutex();
     pInode = inodeList;
     while( pInode && (pInode->fileId.dev!=sStat.st_dev
-                     || pInode->fileId.ino!=sStat.st_ino) ){
+                     || pInode->fileId.ino!=(u64)sStat.st_ino) ){
        pInode = pInode->pNext;
     }
     if( pInode ){
@@ -5481,6 +5544,27 @@ static UnixUnusedFd *findReusableFd(const char *zPath, int flags){
 }
 
 /*
+** Find the mode, uid and gid of file zFile. 
+*/
+static int getFileMode(
+  const char *zFile,              /* File name */
+  mode_t *pMode,                  /* OUT: Permissions of zFile */
+  uid_t *pUid,                    /* OUT: uid of zFile. */
+  gid_t *pGid                     /* OUT: gid of zFile. */
+){
+  struct stat sStat;              /* Output of stat() on database file */
+  int rc = SQLITE_OK;
+  if( 0==osStat(zFile, &sStat) ){
+    *pMode = sStat.st_mode & 0777;
+    *pUid = sStat.st_uid;
+    *pGid = sStat.st_gid;
+  }else{
+    rc = SQLITE_IOERR_FSTAT;
+  }
+  return rc;
+}
+
+/*
 ** This function is called by unixOpen() to determine the unix permissions
 ** to create new files with. If no error occurs, then SQLITE_OK is returned
 ** and a value suitable for passing as the third argument to open(2) is
@@ -5515,7 +5599,6 @@ static int findCreateFileMode(
   if( flags & (SQLITE_OPEN_WAL|SQLITE_OPEN_MAIN_JOURNAL) ){
     char zDb[MAX_PATHNAME+1];     /* Database file path */
     int nDb;                      /* Number of valid bytes in zDb */
-    struct stat sStat;            /* Output of stat() on database file */
 
     /* zPath is a path to a WAL or journal file. The following block derives
     ** the path to the associated database file from zPath. This block handles
@@ -5546,15 +5629,18 @@ static int findCreateFileMode(
     memcpy(zDb, zPath, nDb);
     zDb[nDb] = '\0';
 
-    if( 0==osStat(zDb, &sStat) ){
-      *pMode = sStat.st_mode & 0777;
-      *pUid = sStat.st_uid;
-      *pGid = sStat.st_gid;
-    }else{
-      rc = SQLITE_IOERR_FSTAT;
-    }
+    rc = getFileMode(zDb, pMode, pUid, pGid);
   }else if( flags & SQLITE_OPEN_DELETEONCLOSE ){
     *pMode = 0600;
+  }else if( flags & SQLITE_OPEN_URI ){
+    /* If this is a main database file and the file was opened using a URI
+    ** filename, check for the "modeof" parameter. If present, interpret
+    ** its value as a filename and try to copy the mode, uid and gid from
+    ** that file.  */
+    const char *z = sqlite3_uri_parameter(zPath, "modeof");
+    if( z ){
+      rc = getFileMode(z, pMode, pUid, pGid);
+    }
   }
   return rc;
 }
@@ -5584,7 +5670,7 @@ int chromium_sqlite3_fill_in_unix_sqlite3_file(sqlite3_vfs* pVfs,
   if( eType==SQLITE_OPEN_MAIN_DB ){
     p->pUnused = sqlite3_malloc(sizeof(*p->pUnused));
     if (!p->pUnused) {
-      return SQLITE_NOMEM;
+      return SQLITE_NOMEM_BKPT;
     }
     p->pUnused->fd = fd;
     p->pUnused->flags = flags;
@@ -5710,7 +5796,7 @@ static int unixOpen(
       /* Duplicated in chromium_sqlite3_fill_in_unix_sqlite3_file(). */
       pUnused = sqlite3_malloc64(sizeof(*pUnused));
       if( !pUnused ){
-        return SQLITE_NOMEM;
+        return SQLITE_NOMEM_BKPT;
       }
     }
     p->pUnused = pUnused;
@@ -5797,7 +5883,7 @@ static int unixOpen(
     zPath = sqlite3_mprintf("%s", zName);
     if( zPath==0 ){
       robust_close(p, fd, __LINE__);
-      return SQLITE_NOMEM;
+      return SQLITE_NOMEM_BKPT;
     }
 #else
     osUnlink(zName);
@@ -5808,9 +5894,6 @@ static int unixOpen(
     p->openFlags = openFlags;
   }
 #endif
-
-  noLock = eType!=SQLITE_OPEN_MAIN_DB;
-
   
 #if defined(__APPLE__) || SQLITE_ENABLE_LOCKING_STYLE
   if( fstatfs(fd, &fsInfo) == -1 ){
@@ -5829,6 +5912,7 @@ static int unixOpen(
   /* Set up appropriate ctrlFlags */
   if( isDelete )                ctrlFlags |= UNIXFILE_DELETE;
   if( isReadonly )              ctrlFlags |= UNIXFILE_RDONLY;
+  noLock = eType!=SQLITE_OPEN_MAIN_DB;
   if( noLock )                  ctrlFlags |= UNIXFILE_NOLOCK;
   if( syncDir )                 ctrlFlags |= UNIXFILE_DIRSYNC;
   if( flags & SQLITE_OPEN_URI ) ctrlFlags |= UNIXFILE_URI;
@@ -5907,12 +5991,7 @@ static int unixDelete(
     int fd;
     rc = osOpenDirectory(zPath, &fd);
     if( rc==SQLITE_OK ){
-#if OS_VXWORKS
-      if( fsync(fd)==-1 )
-#else
-      if( fsync(fd) )
-#endif
-      {
+      if( full_fsync(fd,0,0) ){
         rc = unixLogError(SQLITE_IOERR_DIR_FSYNC, "fsync", zPath);
       }
       robust_close(0, fd, __LINE__);
@@ -5958,6 +6037,32 @@ static int unixAccess(
   return SQLITE_OK;
 }
 
+/*
+**
+*/
+static int mkFullPathname(
+  const char *zPath,              /* Input path */
+  char *zOut,                     /* Output buffer */
+  int nOut                        /* Allocated size of buffer zOut */
+){
+  int nPath = sqlite3Strlen30(zPath);
+  int iOff = 0;
+  if( zPath[0]!='/' ){
+    if( osGetcwd(zOut, nOut-2)==0 ){
+      return unixLogError(SQLITE_CANTOPEN_BKPT, "getcwd", zPath);
+    }
+    iOff = sqlite3Strlen30(zOut);
+    zOut[iOff++] = '/';
+  }
+  if( (iOff+nPath+1)>nOut ){
+    /* SQLite assumes that xFullPathname() nul-terminates the output buffer
+    ** even if it returns an error.  */
+    zOut[iOff] = '\0';
+    return SQLITE_CANTOPEN_BKPT;
+  }
+  sqlite3_snprintf(nOut-iOff, &zOut[iOff], "%s", zPath);
+  return SQLITE_OK;
+}
 
 /*
 ** Turn a relative pathname into a full pathname. The relative path
@@ -5974,7 +6079,17 @@ static int unixFullPathname(
   int nOut,                     /* Size of output buffer in bytes */
   char *zOut                    /* Output buffer */
 ){
+#if !defined(HAVE_READLINK) || !defined(HAVE_LSTAT)
+  return mkFullPathname(zPath, zOut, nOut);
+#else
+  int rc = SQLITE_OK;
   int nByte;
+  int nLink = 1;                /* Number of symbolic links followed so far */
+  const char *zIn = zPath;      /* Input path for each iteration of loop */
+  char *zDel = 0;
+
+  assert( pVfs->mxPathname==MAX_PATHNAME );
+  UNUSED_PARAMETER(pVfs);
 
   /* It's odd to simulate an io-error here, but really this is just
   ** using the io-error infrastructure to test that SQLite handles this
@@ -5983,58 +6098,62 @@ static int unixFullPathname(
   */
   SimulateIOError( return SQLITE_ERROR );
 
-  assert( pVfs->mxPathname==MAX_PATHNAME );
-  UNUSED_PARAMETER(pVfs);
+  do {
 
-  /* Attempt to resolve the path as if it were a symbolic link. If it is
-  ** a symbolic link, the resolved path is stored in buffer zOut[]. Or, if
-  ** the identified file is not a symbolic link or does not exist, then
-  ** zPath is copied directly into zOut. Either way, nByte is left set to
-  ** the size of the string copied into zOut[] in bytes.  */
-  nByte = osReadlink(zPath, zOut, nOut-1);
-  if( nByte<0 ){
-    if( errno!=EINVAL && errno!=ENOENT ){
-      return unixLogError(SQLITE_CANTOPEN_BKPT, "readlink", zPath);
-    }
-    sqlite3_snprintf(nOut, zOut, "%s", zPath);
-    nByte = sqlite3Strlen30(zOut);
-  }else{
-    zOut[nByte] = '\0';
-  }
+    /* Call stat() on path zIn. Set bLink to true if the path is a symbolic
+    ** link, or false otherwise.  */
+    int bLink = 0;
+    struct stat buf;
+    if( osLstat(zIn, &buf)!=0 ){
+      if( errno!=ENOENT ){
+        rc = unixLogError(SQLITE_CANTOPEN_BKPT, "lstat", zIn);
+      }
+    }else{
+      bLink = S_ISLNK(buf.st_mode);
+    }
 
-  /* If buffer zOut[] now contains an absolute path there is nothing more
-  ** to do. If it contains a relative path, do the following:
-  **
-  **   * move the relative path string so that it is at the end of th
-  **     zOut[] buffer.
-  **   * Call getcwd() to read the path of the current working directory 
-  **     into the start of the zOut[] buffer.
-  **   * Append a '/' character to the cwd string and move the 
-  **     relative path back within the buffer so that it immediately 
-  **     follows the '/'.
-  **
-  ** This code is written so that if the combination of the CWD and relative
-  ** path are larger than the allocated size of zOut[] the CWD is silently
-  ** truncated to make it fit. This is Ok, as SQLite refuses to open any
-  ** file for which this function returns a full path larger than (nOut-8)
-  ** bytes in size.  */
-  testcase( nByte==nOut-5 );
-  testcase( nByte==nOut-4 );
-  if( zOut[0]!='/' && nByte<nOut-4 ){
-    int nCwd;
-    int nRem = nOut-nByte-1;
-    memmove(&zOut[nRem], zOut, nByte+1);
-    zOut[nRem-1] = '\0';
-    if( osGetcwd(zOut, nRem-1)==0 ){
-      return unixLogError(SQLITE_CANTOPEN_BKPT, "getcwd", zPath);
+    if( bLink ){
+      if( zDel==0 ){
+        zDel = sqlite3_malloc(nOut);
+        if( zDel==0 ) rc = SQLITE_NOMEM_BKPT;
+      }else if( ++nLink>SQLITE_MAX_SYMLINKS ){
+        rc = SQLITE_CANTOPEN_BKPT;
+      }
+
+      if( rc==SQLITE_OK ){
+        nByte = osReadlink(zIn, zDel, nOut-1);
+        if( nByte<0 ){
+          rc = unixLogError(SQLITE_CANTOPEN_BKPT, "readlink", zIn);
+        }else{
+          if( zDel[0]!='/' ){
+            int n;
+            for(n = sqlite3Strlen30(zIn); n>0 && zIn[n-1]!='/'; n--);
+            if( nByte+n+1>nOut ){
+              rc = SQLITE_CANTOPEN_BKPT;
+            }else{
+              memmove(&zDel[n], zDel, nByte+1);
+              memcpy(zDel, zIn, n);
+              nByte += n;
+            }
+          }
+          zDel[nByte] = '\0';
+        }
+      }
+
+      zIn = zDel;
     }
-    nCwd = sqlite3Strlen30(zOut);
-    assert( nCwd<=nRem-1 );
-    zOut[nCwd] = '/';
-    memmove(&zOut[nCwd+1], &zOut[nRem], nByte+1);
-  }
 
-  return SQLITE_OK;
+    assert( rc!=SQLITE_OK || zIn!=zOut || zIn[0]=='/' );
+    if( rc==SQLITE_OK && zIn!=zOut ){
+      rc = mkFullPathname(zIn, zOut, nOut);
+    }
+    if( bLink==0 ) break;
+    zIn = zOut;
+  }while( rc==SQLITE_OK );
+
+  sqlite3_free(zDel);
+  return rc;
+#endif   /* HAVE_READLINK && HAVE_LSTAT */
 }
 
 
@@ -6234,23 +6353,18 @@ static int unixCurrentTime(sqlite3_vfs *NotUsed, double *prNow){
 # define unixCurrentTime 0
 #endif
 
-#ifndef SQLITE_OMIT_DEPRECATED
 /*
-** We added the xGetLastError() method with the intention of providing
-** better low-level error messages when operating-system problems come up
-** during SQLite operation.  But so far, none of that has been implemented
-** in the core.  So this routine is never called.  For now, it is merely
-** a place-holder.
+** The xGetLastError() method is designed to return a better
+** low-level error message when operating-system problems come up
+** during SQLite operation.  Only the integer return code is currently
+** used.
 */
 static int unixGetLastError(sqlite3_vfs *NotUsed, int NotUsed2, char *NotUsed3){
   UNUSED_PARAMETER(NotUsed);
   UNUSED_PARAMETER(NotUsed2);
   UNUSED_PARAMETER(NotUsed3);
-  return 0;
+  return errno;
 }
-#else
-# define unixGetLastError 0
-#endif
 
 
 /*
@@ -6540,7 +6654,7 @@ static int proxyCreateUnixFile(
   }else{
     pUnused = sqlite3_malloc64(sizeof(*pUnused));
     if( !pUnused ){
-      return SQLITE_NOMEM;
+      return SQLITE_NOMEM_BKPT;
     }
   }
   if( fd<0 ){
@@ -6573,7 +6687,7 @@ static int proxyCreateUnixFile(
   
   pNew = (unixFile *)sqlite3_malloc64(sizeof(*pNew));
   if( pNew==NULL ){
-    rc = SQLITE_NOMEM;
+    rc = SQLITE_NOMEM_BKPT;
     goto end_create_proxy;
   }
   memset(pNew, 0, sizeof(unixFile));
@@ -6916,7 +7030,7 @@ static int proxyTakeConch(unixFile *pFile){
         writeSize = PROXY_PATHINDEX + strlen(&writeBuffer[PROXY_PATHINDEX]);
         robust_ftruncate(conchFile->h, writeSize);
         rc = unixWrite((sqlite3_file *)conchFile, writeBuffer, writeSize, 0);
-        fsync(conchFile->h);
+        full_fsync(conchFile->h,0,0);
         /* If we created a new conch file (not just updated the contents of a 
          ** valid conch file), try to match the permissions of the database 
          */
@@ -6986,7 +7100,7 @@ static int proxyTakeConch(unixFile *pFile){
         if( tempLockPath ){
           pCtx->lockProxyPath = sqlite3DbStrDup(0, tempLockPath);
           if( !pCtx->lockProxyPath ){
-            rc = SQLITE_NOMEM;
+            rc = SQLITE_NOMEM_BKPT;
           }
         }
       }
@@ -7051,7 +7165,7 @@ static int proxyCreateConchPathname(char *dbPath, char **pConchPath){
   ** the name of the original database file. */  
   *pConchPath = conchPath = (char *)sqlite3_malloc64(len + 8);
   if( conchPath==0 ){
-    return SQLITE_NOMEM;
+    return SQLITE_NOMEM_BKPT;
   }
   memcpy(conchPath, dbPath, len+1);
   
@@ -7167,7 +7281,7 @@ static int proxyTransformUnixFile(unixFile *pFile, const char *path) {
 
   pCtx = sqlite3_malloc64( sizeof(*pCtx) );
   if( pCtx==0 ){
-    return SQLITE_NOMEM;
+    return SQLITE_NOMEM_BKPT;
   }
   memset(pCtx, 0, sizeof(*pCtx));
 
@@ -7203,7 +7317,7 @@ static int proxyTransformUnixFile(unixFile *pFile, const char *path) {
   if( rc==SQLITE_OK ){
     pCtx->dbPath = sqlite3DbStrDup(0, dbPath);
     if( pCtx->dbPath==NULL ){
-      rc = SQLITE_NOMEM;
+      rc = SQLITE_NOMEM_BKPT;
     }
   }
   if( rc==SQLITE_OK ){
@@ -7533,7 +7647,7 @@ int sqlite3_os_init(void){
 
   /* Double-check that the aSyscall[] array has been constructed
   ** correctly.  See ticket [bb3a86e890c8e96ab] */
-  assert( ArraySize(aSyscall)==27 );
+  assert( ArraySize(aSyscall)==28 );
 
   /* Register all VFSes defined in the aVfs[] array */
   for(i=0; i<(sizeof(aVfs)/sizeof(sqlite3_vfs)); i++){