newlib-cygwin/winsup/mingw/mingwex/dirent.c

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/*
* dirent.c
*
* This file has no copyright assigned and is placed in the Public Domain.
* This file is a part of the mingw-runtime package.
* No warranty is given; refer to the file DISCLAIMER within the package.
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*
* Derived from DIRLIB.C by Matt J. Weinstein
* This note appears in the DIRLIB.H
* DIRLIB.H by M. J. Weinstein Released to public domain 1-Jan-89
*
* Updated by Jeremy Bettis <jeremy@hksys.com>
* Significantly revised and rewinddir, seekdir and telldir added
* by Colin Peters <colin@fu.is.saga-u.ac.jp>
*
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*/
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <io.h>
#include <direct.h>
#include <dirent.h>
#define WIN32_LEAN_AND_MEAN
#include <windows.h> /* for GetFileAttributes */
#include <tchar.h>
#define SUFFIX _T("*")
#define SLASH _T("\\")
#define DIRENT_RETURN_NOTHING
#define DIRENT_REJECT( chk, err, rtn ) \
do { if( chk ){ errno = (err); return rtn; }} while(0)
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union __dirstream_t
{
/* Actual (private) declaration for opaque data type "DIR". */
/* dirent struct to return from dir (NOTE: this makes this thread
* safe as long as only one thread uses a particular DIR struct at
* a time) */
struct dirent dd_dir;
struct __dirstream_private_t
{
/* Three padding fields, matching the head of dd_dir...
*/
long dd_ino; /* Always zero. */
unsigned short dd_reclen; /* Always zero. */
unsigned short dd_namlen; /* Length of name in d_name. */
/* ...to keep the start of this disk transfer area for this dir
* aligned at the offset of the dd_dir.d_type field
*/
struct _finddata_t dd_dta;
/* _findnext handle */
intptr_t dd_handle;
/* Status of search:
* (type is now int -- was short in older versions).
* 0 = not started yet (next entry to read is first entry)
* -1 = off the end
* positive = 0 based index of next entry
*/
int dd_stat;
/* given path for dir with search pattern (struct is extended) */
char dd_name[1];
} dd_private;
};
union __wdirstream_t
{
/* Actual (private) declaration for opaque data type "_WDIR". */
/* dirent struct to return from dir (NOTE: this makes this thread
* safe as long as only one thread uses a particular DIR struct at
* a time) */
struct _wdirent dd_dir;
struct __wdirstream_private_t
{
/* Three padding fields, matching the head of dd_dir...
*/
long dd_ino; /* Always zero. */
unsigned short dd_reclen; /* Always zero. */
unsigned short dd_namlen; /* Length of name in d_name. */
/* ...to keep the start of this disk transfer area for this dir
* aligned at the offset of the dd_dir.d_type field
*/
struct _wfinddata_t dd_dta;
/* _findnext handle */
intptr_t dd_handle;
/* Status of search:
* 0 = not started yet (next entry to read is first entry)
* -1 = off the end
* positive = 0 based index of next entry
*/
int dd_stat;
/* given path for dir with search pattern (struct is extended) */
wchar_t dd_name[1];
} dd_private;
};
/* We map the BSD d_type field in the returned dirent structure
* from the Microsoft _finddata_t dd_dta.attrib bits, which are:
*
* _A_NORMAL (0x0000) normal file: best fit for DT_REG
* _A_RDONLY (0x0001) read-only: no BSD d_type equivalent
* _A_HIDDEN (0x0002) hidden entity: no BSD equivalent
* _A_SYSTEM (0x0004) system entity: no BSD equivalent
* _A_VOLID (0x0008) volume label: no BSD equivalent
* _A_SUBDIR (0x0010) directory: best fit for DT_DIR
* _A_ARCH (0x0020) "dirty": no BSD equivalent
*
* Of these, _A_RDONLY, _A_HIDDEN, _A_SYSTEM, and _A_ARCH are
* modifier bits, rather than true entity type specifiers; we
* will ignore them in the mapping, by applying this mask:
*/
#define DT_IGNORED (_A_RDONLY | _A_HIDDEN | _A_SYSTEM | _A_ARCH)
/* Helper for opendir(). */
static inline unsigned _tGetFileAttributes (const _TCHAR * tPath)
{
#ifdef _UNICODE
/* GetFileAttributesW does not work on W9x, so convert to ANSI */
if (_osver & 0x8000)
{
char aPath [MAX_PATH];
WideCharToMultiByte (CP_ACP, 0, tPath, -1, aPath, MAX_PATH, NULL,
NULL);
return GetFileAttributesA (aPath);
}
return GetFileAttributesW (tPath);
#else
return GetFileAttributesA (tPath);
#endif
}
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/*
* opendir
*
* Returns a pointer to a DIR structure appropriately filled in to begin
* searching a directory.
*/
_TDIR *
_topendir (const _TCHAR *szPath)
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{
_TDIR *nd;
unsigned int rc;
_TCHAR szFullPath[MAX_PATH];
/* Reject any request which passes a NULL or an empty path name;
* note that POSIX doesn't specify the handling for the NULL case,
* and some implementations may simply fail with a segmentation
* fault. We will fail more gracefully; however, the choice of
* EFAULT is not specified by POSIX, for any opendir failure.
*/
DIRENT_REJECT( (!szPath), EFAULT, (_TDIR *)(0) );
/*
* Conversely, POSIX *does* specify ENOENT for the empty path
* name case, where we previously had ENOTDIR; here, we correct
* this previous anomaly.
*/
DIRENT_REJECT( (*szPath == _T('\0')), ENOENT, (_TDIR *)(0) );
/* Attempt to determine if the given path really is a directory.
* On error, user may call GetLastError() for more error info
*/
DIRENT_REJECT( ((rc = _tGetFileAttributes (szPath)) == (unsigned int)(-1)),
ENOENT, (_TDIR *)(0)
);
/* Error, entry exists but not a directory.
*/
DIRENT_REJECT( (!(rc & FILE_ATTRIBUTE_DIRECTORY)), ENOTDIR, (_TDIR *)(0) );
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/* Make an absolute pathname. */
_tfullpath (szFullPath, szPath, MAX_PATH);
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/* Allocate enough space to store DIR structure and the complete
* directory path given. */
nd = (_TDIR *)(malloc( sizeof( _TDIR )
+ (_tcslen( szFullPath ) + _tcslen( SLASH ) + _tcslen( SUFFIX ) + 1)
* sizeof( _TCHAR )
));
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/* Error, out of memory.
*/
DIRENT_REJECT( (!nd), ENOMEM, (_TDIR *)(0) );
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/* Create the search expression. */
_tcscpy (nd->dd_private.dd_name, szFullPath);
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/* Add on a slash if the path does not end with one. */
if (nd->dd_private.dd_name[0] != _T('\0')
&& _tcsrchr (nd->dd_private.dd_name, _T('/')) != nd->dd_private.dd_name
+ _tcslen (nd->dd_private.dd_name) - 1
&& _tcsrchr (nd->dd_private.dd_name, _T('\\')) != nd->dd_private.dd_name
+ _tcslen (nd->dd_private.dd_name) - 1)
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{
_tcscat (nd->dd_private.dd_name, SLASH);
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}
/* Add on the search pattern */
_tcscat (nd->dd_private.dd_name, SUFFIX);
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/* Initialize handle to -1 so that a premature closedir doesn't try
* to call _findclose on it. */
nd->dd_private.dd_handle = -1;
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/* Initialize the status. */
nd->dd_private.dd_stat = 0;
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/* Initialize the dirent structure. ino and reclen are invalid under
* Win32, and name simply points at the appropriate part of the
* findfirst_t structure. */
nd->dd_dir.d_ino = 0;
nd->dd_dir.d_reclen = 0;
nd->dd_dir.d_namlen = 0;
memset (nd->dd_dir.d_name, 0, FILENAME_MAX);
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return nd;
}
/*
* readdir
*
* Return a pointer to a dirent structure filled with the information on the
* next entry in the directory.
*/
struct _tdirent *
_treaddir (_TDIR *dirp)
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{
/* Check for a valid DIR stream reference; (we can't really
* be certain until we try to read from it, except in the case
* of a NULL pointer reference). Where we lack a valid reference,
* POSIX mandates reporting EBADF; we previously had EFAULT, so
* this version corrects the former anomaly.
*/
DIRENT_REJECT( (!dirp), EBADF, (struct _tdirent *)(0) );
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if (dirp->dd_private.dd_stat < 0)
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{
/* We have already returned all files in the directory
* (or the structure has an invalid dd_stat). */
return (struct _tdirent *) 0;
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}
else if (dirp->dd_private.dd_stat == 0)
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{
/* We haven't started the search yet. */
/* Start the search */
dirp->dd_private.dd_handle = _tfindfirst (dirp->dd_private.dd_name, &(dirp->dd_private.dd_dta));
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if (dirp->dd_private.dd_handle == -1)
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{
/* Oops! Seems there are no files in that
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* directory. */
dirp->dd_private.dd_stat = -1;
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}
else
{
dirp->dd_private.dd_stat = 1;
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}
}
else
{
/* Get the next search entry. POSIX mandates that this must
* return NULL after the last entry has been read, but that it
* MUST NOT change errno in this case. MS-Windows _findnext()
* DOES change errno (to ENOENT) after the last entry has been
* read, so we must be prepared to restore it to its previous
* value, when no actual error has occurred.
*/
int prev_errno = errno;
if (_tfindnext (dirp->dd_private.dd_handle, &(dirp->dd_private.dd_dta)))
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{
/* May be an error, or just the case described above...
*/
if( GetLastError() == ERROR_NO_MORE_FILES )
/*
* ...which requires us to reset errno.
*/
errno = prev_errno;
/* FIXME: this is just wrong: we should NOT close the DIR
* handle here; it is the responsibility of closedir().
*/
_findclose (dirp->dd_private.dd_handle);
dirp->dd_private.dd_handle = -1;
dirp->dd_private.dd_stat = -1;
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}
else
{
/* Update the status to indicate the correct
* number. */
dirp->dd_private.dd_stat++;
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}
}
if (dirp->dd_private.dd_stat > 0)
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{
/* Successfully got an entry. Everything about the file is
* already appropriately filled in except the length of the
* file name...
*/
dirp->dd_dir.d_namlen = _tcslen (dirp->dd_dir.d_name);
/*
* ...and the attributes returned in the dd_dta.attrib field;
* these require adjustment to their BSD equivalents, which are
* returned via the union with the dd_dir.d_type field:
*/
switch( dirp->dd_dir.d_type &= ~DT_IGNORED )
{
case DT_REG:
case DT_DIR:
/* After stripping out the modifier bits in DT_IGNORED,
* (which we ALWAYS ignore), this pair require no further
* adjustment...
*/
break;
default:
/* ...while nothing else has an appropriate equivalent
* in the BSD d_type identification model.
*/
dirp->dd_dir.d_type = DT_UNKNOWN;
}
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return &dirp->dd_dir;
}
return (struct _tdirent *) 0;
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}
/*
* closedir
*
* Frees up resources allocated by opendir.
*/
int
_tclosedir (_TDIR * dirp)
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{
int rc = 0;
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/* Attempting to reference a directory stream via a NULL pointer
* would cause a segmentation fault; evade this. Since NULL can
* never represent an open directory stream, set the EBADF errno
* status, as mandated by POSIX, once again correcting previous
* anomalous use of EFAULT in this context.
*/
DIRENT_REJECT( (!dirp), EBADF, -1 );
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if (dirp->dd_private.dd_handle != -1)
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{
rc = _findclose (dirp->dd_private.dd_handle);
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}
/* Delete the dir structure. */
free (dirp);
return rc;
}
/*
* rewinddir
*
* Return to the beginning of the directory "stream". We simply call findclose
* and then reset things like an opendir.
*/
void
_trewinddir (_TDIR * dirp)
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{
/* Once again, evade a potential segmentation fault on passing
* a NULL reference pointer, and again correct previous anomalous
* use of EFAULT, where POSIX mandates EBADF for errno reporting.
*/
DIRENT_REJECT( (!dirp), EBADF, DIRENT_RETURN_NOTHING );
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if (dirp->dd_private.dd_handle != -1)
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{
_findclose (dirp->dd_private.dd_handle);
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}
dirp->dd_private.dd_handle = -1;
dirp->dd_private.dd_stat = 0;
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}
/*
* telldir
*
* Returns the "position" in the "directory stream" which can be used with
* seekdir to go back to an old entry. We simply return the value in stat.
*/
long
_ttelldir (_TDIR * dirp)
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{
/* Once again, evade a potential segmentation fault on passing
* a NULL reference pointer, and again correct previous anomalous
* use of EFAULT, where POSIX mandates EBADF for errno reporting.
*/
DIRENT_REJECT( (!dirp), EBADF, -1 );
return dirp->dd_private.dd_stat;
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}
/*
* seekdir
*
* Seek to an entry previously returned by telldir. We rewind the directory
* and call readdir repeatedly until either dd_stat is the position number
* or -1 (off the end). This is not perfect, in that the directory may
* have changed while we weren't looking. But that is probably the case with
* any such system.
*/
void
_tseekdir (_TDIR * dirp, long lPos)
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{
/* Once again, evade a potential segmentation fault on passing
* a NULL reference pointer, and again correct previous anomalous
* use of EFAULT, where POSIX mandates EBADF for errno reporting.
*/
DIRENT_REJECT( (!dirp), EBADF, DIRENT_RETURN_NOTHING );
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/* Seeking to an invalid position.
*/
DIRENT_REJECT( (lPos < -1), EINVAL, DIRENT_RETURN_NOTHING );
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if (lPos == -1)
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{
/* Seek past end. */
if (dirp->dd_private.dd_handle != -1)
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{
_findclose (dirp->dd_private.dd_handle);
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}
dirp->dd_private.dd_handle = -1;
dirp->dd_private.dd_stat = -1;
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}
else
{
/* Rewind and read forward to the appropriate index. */
_trewinddir (dirp);
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while ((dirp->dd_private.dd_stat < lPos) && _treaddir (dirp))
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;
}
}