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/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 1997, 2012 Oracle and/or its affiliates. All rights reserved.
*
* $Id$
*/
#include "db_config.h"
#include "db_int.h"
/*
* __os_open --
* Open a file descriptor (including page size and log size information).
*/
int
__os_open(env, name, page_size, flags, mode, fhpp)
ENV *env;
const char *name;
u_int32_t page_size, flags;
int mode;
DB_FH **fhpp;
{
DB_ENV *dbenv;
DB_FH *fhp;
#ifndef DB_WINCE
DWORD cluster_size, sector_size, free_clusters, total_clusters;
_TCHAR *drive, dbuf[4]; /* <letter><colon><slash><nul> */
#endif
int access, attr, createflag, nrepeat, ret, share;
_TCHAR *tname;
dbenv = env == NULL ? NULL : env->dbenv;
*fhpp = NULL;
tname = NULL;
if (dbenv != NULL &&
FLD_ISSET(dbenv->verbose, DB_VERB_FILEOPS | DB_VERB_FILEOPS_ALL))
__db_msg(env, DB_STR_A("0025", "fileops: open %s",
"%s"), name);
#undef OKFLAGS
#define OKFLAGS \
(DB_OSO_ABSMODE | DB_OSO_CREATE | DB_OSO_DIRECT | DB_OSO_DSYNC |\
DB_OSO_EXCL | DB_OSO_RDONLY | DB_OSO_REGION | DB_OSO_SEQ | \
DB_OSO_TEMP | DB_OSO_TRUNC)
if ((ret = __db_fchk(env, "__os_open", flags, OKFLAGS)) != 0)
return (ret);
TO_TSTRING(env, name, tname, ret);
if (ret != 0)
goto err;
/*
* Allocate the file handle and copy the file name. We generally only
* use the name for verbose or error messages, but on systems where we
* can't unlink temporary files immediately, we use the name to unlink
* the temporary file when the file handle is closed.
*
* Lock the ENV handle and insert the new file handle on the list.
*/
if ((ret = __os_calloc(env, 1, sizeof(DB_FH), &fhp)) != 0)
return (ret);
if ((ret = __os_strdup(env, name, &fhp->name)) != 0)
goto err;
if (env != NULL) {
MUTEX_LOCK(env, env->mtx_env);
TAILQ_INSERT_TAIL(&env->fdlist, fhp, q);
MUTEX_UNLOCK(env, env->mtx_env);
F_SET(fhp, DB_FH_ENVLINK);
}
/*
* Otherwise, use the Windows/32 CreateFile interface so that we can
* play magic games with files to get data flush effects similar to
* the POSIX O_DSYNC flag.
*
* !!!
* We currently ignore the 'mode' argument. It would be possible
* to construct a set of security attributes that we could pass to
* CreateFile that would accurately represents the mode. In worst
* case, this would require looking up user and all group names and
* creating an entry for each. Alternatively, we could call the
* _chmod (partial emulation) function after file creation, although
* this leaves us with an obvious race. However, these efforts are
* largely meaningless on FAT, the most common file system, which
* only has a "readable" and "writable" flag, applying to all users.
*/
access = GENERIC_READ;
if (!LF_ISSET(DB_OSO_RDONLY))
access |= GENERIC_WRITE;
#ifdef DB_WINCE
/*
* WinCE translates these flags into share flags for
* CreateFileForMapping.
* Also WinCE does not support the FILE_SHARE_DELETE flag.
*/
if (LF_ISSET(DB_OSO_REGION))
share = GENERIC_READ | GENERIC_WRITE;
else
share = FILE_SHARE_READ | FILE_SHARE_WRITE;
#else
share = FILE_SHARE_READ | FILE_SHARE_WRITE;
if (__os_is_winnt())
share |= FILE_SHARE_DELETE;
#endif
attr = FILE_ATTRIBUTE_NORMAL;
/*
* Reproduce POSIX 1003.1 semantics: if O_CREATE and O_EXCL are both
* specified, fail, returning EEXIST, unless we create the file.
*/
if (LF_ISSET(DB_OSO_CREATE) && LF_ISSET(DB_OSO_EXCL))
createflag = CREATE_NEW; /* create only if !exist*/
else if (!LF_ISSET(DB_OSO_CREATE) && LF_ISSET(DB_OSO_TRUNC))
createflag = TRUNCATE_EXISTING; /* truncate, fail if !exist */
else if (LF_ISSET(DB_OSO_TRUNC))
createflag = CREATE_ALWAYS; /* create and truncate */
else if (LF_ISSET(DB_OSO_CREATE))
createflag = OPEN_ALWAYS; /* open or create */
else
createflag = OPEN_EXISTING; /* open only if existing */
if (LF_ISSET(DB_OSO_DSYNC)) {
F_SET(fhp, DB_FH_NOSYNC);
attr |= FILE_FLAG_WRITE_THROUGH;
}
#ifndef DB_WINCE
if (LF_ISSET(DB_OSO_SEQ))
attr |= FILE_FLAG_SEQUENTIAL_SCAN;
else
attr |= FILE_FLAG_RANDOM_ACCESS;
#endif
if (LF_ISSET(DB_OSO_TEMP))
attr |= FILE_FLAG_DELETE_ON_CLOSE;
/*
* We can turn filesystem buffering off if the page size is a
* multiple of the disk's sector size. To find the sector size,
* we call GetDiskFreeSpace, which expects a drive name like "d:\\"
* or NULL for the current disk (i.e., a relative path).
*
* WinCE only has GetDiskFreeSpaceEx which does not
* return the sector size.
*/
#ifndef DB_WINCE
if (LF_ISSET(DB_OSO_DIRECT) && page_size != 0 && name[0] != '\0') {
if (name[1] == ':') {
drive = dbuf;
_sntprintf(dbuf, sizeof(dbuf), _T("%c:\\"), tname[0]);
} else
drive = NULL;
/*
* We ignore all results except sectorsize, but some versions
* of Windows require that the parameters are non-NULL.
*/
if (GetDiskFreeSpace(drive, &cluster_size,
§or_size, &free_clusters, &total_clusters) &&
page_size % sector_size == 0)
attr |= FILE_FLAG_NO_BUFFERING;
}
#endif
fhp->handle = fhp->trunc_handle = INVALID_HANDLE_VALUE;
for (nrepeat = 1;; ++nrepeat) {
if (fhp->handle == INVALID_HANDLE_VALUE) {
#ifdef DB_WINCE
if (LF_ISSET(DB_OSO_REGION))
fhp->handle = CreateFileForMapping(tname,
access, share, NULL, createflag, attr, 0);
else
#endif
fhp->handle = CreateFile(tname,
access, share, NULL, createflag, attr, 0);
}
#ifdef HAVE_FTRUNCATE
/*
* Older versions of WinCE may not support truncate, if so, the
* HAVE_FTRUNCATE macro should be #undef'ed, and we
* don't need to open this second handle.
*
* WinCE dose not support opening a second handle on the same
* file via CreateFileForMapping, but this dose not matter
* since we are not truncating region files but database files.
*
* But some older versions of WinCE even
* dose not allow a second handle opened via CreateFile. If
* this is the case, users will need to #undef the
* HAVE_FTRUNCATE macro in build_wince/db_config.h.
*/
/*
* Windows does not provide truncate directly. There is no
* safe way to use a handle for truncate concurrently with
* reads or writes. To deal with this, we open a second handle
* used just for truncating.
*/
if (fhp->handle != INVALID_HANDLE_VALUE &&
!LF_ISSET(DB_OSO_RDONLY | DB_OSO_TEMP) &&
fhp->trunc_handle == INVALID_HANDLE_VALUE
#ifdef DB_WINCE
/* Do not open trunc handle for region files. */
&& (!LF_ISSET(DB_OSO_REGION))
#endif
)
fhp->trunc_handle = CreateFile(
tname, access, share, NULL, OPEN_EXISTING, attr, 0);
#endif
#ifndef HAVE_FTRUNCATE
if (fhp->handle == INVALID_HANDLE_VALUE)
#else
if (fhp->handle == INVALID_HANDLE_VALUE ||
(!LF_ISSET(DB_OSO_RDONLY | DB_OSO_TEMP) &&
fhp->trunc_handle == INVALID_HANDLE_VALUE
#ifdef DB_WINCE
/* Do not open trunc handle for region files. */
&& (!LF_ISSET(DB_OSO_REGION))
#endif
))
#endif
{
/*
* If it's a "temporary" error, we retry up to 3 times,
* waiting up to 12 seconds. While it's not a problem
* if we can't open a database, an inability to open a
* log file is cause for serious dismay.
*/
ret = __os_posix_err(__os_get_syserr());
if ((ret != ENFILE && ret != EMFILE && ret != ENOSPC) ||
nrepeat > 3)
goto err;
__os_yield(env, nrepeat * 2, 0);
} else
break;
}
FREE_STRING(env, tname);
if (LF_ISSET(DB_OSO_REGION))
F_SET(fhp, DB_FH_REGION);
F_SET(fhp, DB_FH_OPENED);
*fhpp = fhp;
return (0);
err: FREE_STRING(env, tname);
if (fhp != NULL)
(void)__os_closehandle(env, fhp);
return (ret);
}
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