/*
* 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.
* 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>
+ * Significantly revised and rewinddir, seekdir and telldir added
+ * by Colin Peters <colin@fu.is.saga-u.ac.jp>
*
*/
#include <tchar.h>
#define SUFFIX _T("*")
-#define SLASH _T("\\")
+#define SLASH _T("\\")
+
+#define DIRENT_RETURN_NOTHING
+#define DIRENT_REJECT( chk, err, rtn ) \
+ do { if( chk ){ errno = (err); return rtn; }} while(0)
union __dirstream_t
{
unsigned int rc;
_TCHAR szFullPath[MAX_PATH];
- errno = 0;
-
- if (!szPath)
- {
- errno = EFAULT;
- return (_TDIR *) 0;
- }
-
- if (szPath[0] == _T('\0'))
- {
- errno = ENOTDIR;
- return (_TDIR *) 0;
- }
-
- /* Attempt to determine if the given path really is a directory. */
- rc = _tGetFileAttributes (szPath);
- if (rc == (unsigned int)-1)
- {
- /* call GetLastError for more error info */
- errno = ENOENT;
- return (_TDIR *) 0;
- }
- if (!(rc & FILE_ATTRIBUTE_DIRECTORY))
- {
- /* Error, entry exists but not a directory. */
- errno = ENOTDIR;
- return (_TDIR *) 0;
- }
+ /* 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) );
/* Make an absolute pathname. */
_tfullpath (szFullPath, szPath, MAX_PATH);
/* 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));
+ nd = (_TDIR *)(malloc( sizeof( _TDIR )
+ + (_tcslen( szFullPath ) + _tcslen( SLASH ) + _tcslen( SUFFIX ) + 1)
+ * sizeof( _TCHAR )
+ ));
- if (!nd)
- {
- /* Error, out of memory. */
- errno = ENOMEM;
- return (_TDIR *) 0;
- }
+ /* Error, out of memory.
+ */
+ DIRENT_REJECT( (!nd), ENOMEM, (_TDIR *)(0) );
/* Create the search expression. */
_tcscpy (nd->dd_private.dd_name, szFullPath);
* next entry in the directory.
*/
struct _tdirent *
-_treaddir (_TDIR * dirp)
+_treaddir (_TDIR *dirp)
{
- errno = 0;
-
- /* Check for valid DIR struct. */
- if (!dirp)
- {
- errno = EFAULT;
- return (struct _tdirent *) 0;
- }
+ /* 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) );
if (dirp->dd_private.dd_stat < 0)
{
if (dirp->dd_private.dd_handle == -1)
{
- /* Whoops! Seems there are no files in that
+ /* Oops! Seems there are no files in that
* directory. */
dirp->dd_private.dd_stat = -1;
}
}
else
{
- /* Get the next search entry. */
+ /* 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)))
{
- /* We are off the end or otherwise error.
- _findnext sets errno to ENOENT if no more file
- Undo this. */
- DWORD winerr = GetLastError ();
- if (winerr == ERROR_NO_MORE_FILES)
- errno = 0;
+ /* 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;
int
_tclosedir (_TDIR * dirp)
{
- int rc;
+ int rc = 0;
- errno = 0;
- rc = 0;
-
- if (!dirp)
- {
- errno = EFAULT;
- return -1;
- }
+ /* 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 );
if (dirp->dd_private.dd_handle != -1)
{
void
_trewinddir (_TDIR * dirp)
{
- errno = 0;
-
- if (!dirp)
- {
- errno = EFAULT;
- return;
- }
+ /* 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 );
if (dirp->dd_private.dd_handle != -1)
{
long
_ttelldir (_TDIR * dirp)
{
- errno = 0;
-
- if (!dirp)
- {
- errno = EFAULT;
- return -1;
- }
+ /* 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;
}
void
_tseekdir (_TDIR * dirp, long lPos)
{
- errno = 0;
+ /* 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 );
- if (!dirp)
- {
- errno = EFAULT;
- return;
- }
+ /* Seeking to an invalid position.
+ */
+ DIRENT_REJECT( (lPos < -1), EINVAL, DIRENT_RETURN_NOTHING );
- if (lPos < -1)
- {
- /* Seeking to an invalid position. */
- errno = EINVAL;
- return;
- }
- else if (lPos == -1)
+ if (lPos == -1)
{
/* Seek past end. */
if (dirp->dd_private.dd_handle != -1)
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