/*
* Common routine for opendir(3), __opendir2(3) and fdopendir(3).
*/
static DIR *
__opendir_common(int fd, int flags, bool use_current_pos)
{
DIR *dirp;
int incr;
int saved_errno;
int unionstack;
if ((dirp = malloc(sizeof(DIR) + sizeof(struct _telldir))) == NULL)
return (NULL);
dirp->dd_buf = NULL;
dirp->dd_fd = fd;
dirp->dd_flags = flags;
dirp->dd_loc = 0;
dirp->dd_lock = NULL;
dirp->dd_td = (struct _telldir *)((char *)dirp + sizeof(DIR));
LIST_INIT(&dirp->dd_td->td_locq);
dirp->dd_td->td_loccnt = 0;
/*
* Use the system page size if that is a multiple of DIRBLKSIZ.
* Hopefully this can be a big win someday by allowing page
* trades to user space to be done by _getdirentries().
*/
incr = getpagesize();
if ((incr % DIRBLKSIZ) != 0)
incr = DIRBLKSIZ;
/*
* Determine whether this directory is the top of a union stack.
*/
if (flags & DTF_NODUP) {
struct statfs sfb;
if (_fstatfs(fd, &sfb) < 0)
goto fail;
unionstack = !strcmp(sfb.f_fstypename, "unionfs")
|| (sfb.f_flags & MNT_UNION);
} else {
unionstack = 0;
}
if (unionstack) {
if (!_filldir(dirp, use_current_pos))
goto fail;
dirp->dd_flags |= __DTF_READALL;
} else {
dirp->dd_len = incr;
dirp->dd_buf = malloc(dirp->dd_len);
if (dirp->dd_buf == NULL)
goto fail;
if (use_current_pos) {
/*
* Read the first batch of directory entries
* to prime dd_seek. This also checks if the
* fd passed to fdopendir() is a directory.
*/
dirp->dd_size = _getdirentries(dirp->dd_fd,
dirp->dd_buf, dirp->dd_len, &dirp->dd_seek);
if (dirp->dd_size < 0) {
if (errno == EINVAL)
errno = ENOTDIR;
goto fail;
}
dirp->dd_flags |= __DTF_SKIPREAD;
} else {
dirp->dd_size = 0;
dirp->dd_seek = 0;
}
}
return (dirp);
fail:
saved_errno = errno;
free(dirp->dd_buf);
free(dirp);
errno = saved_errno;
return (NULL);
}
/*
* Common routine for opendir(3), __opendir2(3) and fdopendir(3).
*/
static DIR *
__opendir_common(int fd, const char *name, int flags)
{
DIR *dirp;
int incr;
int saved_errno;
int unionstack;
struct stat statb;
dirp = NULL;
/* _fstat() the open handler because the file may have changed. */
if (_fstat(fd, &statb) != 0)
goto fail;
if (!S_ISDIR(statb.st_mode)) {
errno = ENOTDIR;
goto fail;
}
if (_fcntl(fd, F_SETFD, FD_CLOEXEC) == -1 ||
(dirp = malloc(sizeof(DIR) + sizeof(struct _telldir))) == NULL)
goto fail;
dirp->dd_td = (struct _telldir *)((char *)dirp + sizeof(DIR));
LIST_INIT(&dirp->dd_td->td_locq);
dirp->dd_td->td_loccnt = 0;
/*
* Use the system page size if that is a multiple of DIRBLKSIZ.
* Hopefully this can be a big win someday by allowing page
* trades to user space to be done by _getdirentries().
*/
incr = getpagesize();
if ((incr % DIRBLKSIZ) != 0)
incr = DIRBLKSIZ;
/*
* Determine whether this directory is the top of a union stack.
*/
if (flags & DTF_NODUP) {
struct statfs sfb;
if (_fstatfs(fd, &sfb) < 0)
goto fail;
unionstack = !strcmp(sfb.f_fstypename, "unionfs")
|| (sfb.f_flags & MNT_UNION);
} else {
unionstack = 0;
}
if (unionstack) {
int len = 0;
int space = 0;
char *buf = 0;
char *ddptr = 0;
char *ddeptr;
int n;
struct dirent **dpv;
/*
* The strategy here is to read all the directory
* entries into a buffer, sort the buffer, and
* remove duplicate entries by setting the inode
* number to zero.
*/
do {
/*
* Always make at least DIRBLKSIZ bytes
* available to _getdirentries
*/
if (space < DIRBLKSIZ) {
space += incr;
len += incr;
buf = reallocf(buf, len);
if (buf == NULL)
goto fail;
ddptr = buf + (len - space);
}
n = _getdirentries(fd, ddptr, space, &dirp->dd_seek);
if (n > 0) {
ddptr += n;
space -= n;
}
} while (n > 0);
ddeptr = ddptr;
flags |= __DTF_READALL;
/*
* Re-open the directory.
* This has the effect of rewinding back to the
* top of the union stack and is needed by
* programs which plan to fchdir to a descriptor
* which has also been read -- see fts.c.
*/
if (flags & DTF_REWIND) {
(void)_close(fd);
if ((fd = _open(name, O_RDONLY | O_DIRECTORY)) == -1) {
saved_errno = errno;
free(buf);
free(dirp);
errno = saved_errno;
return (NULL);
}
}
/*
* There is now a buffer full of (possibly) duplicate
* names.
*/
dirp->dd_buf = buf;
/*
* Go round this loop twice...
*
* Scan through the buffer, counting entries.
* On the second pass, save pointers to each one.
* Then sort the pointers and remove duplicate names.
*/
for (dpv = 0;;) {
n = 0;
ddptr = buf;
while (ddptr < ddeptr) {
struct dirent *dp;
dp = (struct dirent *) ddptr;
if ((long)dp & 03L)
break;
if ((dp->d_reclen <= 0) ||
(dp->d_reclen > (ddeptr + 1 - ddptr)))
break;
ddptr += dp->d_reclen;
if (dp->d_fileno) {
if (dpv)
dpv[n] = dp;
n++;
}
}
if (dpv) {
struct dirent *xp;
/*
* This sort must be stable.
*/
mergesort(dpv, n, sizeof(*dpv),
opendir_compar);
dpv[n] = NULL;
xp = NULL;
/*
* Scan through the buffer in sort order,
* zapping the inode number of any
* duplicate names.
*/
for (n = 0; dpv[n]; n++) {
struct dirent *dp = dpv[n];
if ((xp == NULL) ||
strcmp(dp->d_name, xp->d_name)) {
xp = dp;
} else {
dp->d_fileno = 0;
}
if (dp->d_type == DT_WHT &&
(flags & DTF_HIDEW))
dp->d_fileno = 0;
}
free(dpv);
break;
} else {
dpv = malloc((n+1) * sizeof(struct dirent *));
if (dpv == NULL)
break;
}
}
dirp->dd_len = len;
dirp->dd_size = ddptr - dirp->dd_buf;
} else {
dirp->dd_len = incr;
dirp->dd_size = 0;
dirp->dd_buf = malloc(dirp->dd_len);
if (dirp->dd_buf == NULL)
goto fail;
dirp->dd_seek = 0;
flags &= ~DTF_REWIND;
}
dirp->dd_loc = 0;
dirp->dd_fd = fd;
dirp->dd_flags = flags;
dirp->dd_lock = NULL;
/*
* Set up seek point for rewinddir.
*/
dirp->dd_rewind = telldir(dirp);
return (dirp);
fail:
saved_errno = errno;
free(dirp);
(void)_close(fd);
errno = saved_errno;
return (NULL);
}
/*
* For a directory at the top of a unionfs stack, the entire directory's
* contents are read and cached locally until the next call to rewinddir().
* For the fdopendir() case, the initial seek position must be preserved.
* For rewinddir(), the full directory should always be re-read from the
* beginning.
*
* If an error occurs, the existing buffer and state of 'dirp' is left
* unchanged.
*/
bool
_filldir(DIR *dirp, bool use_current_pos)
{
struct dirent **dpv;
char *buf, *ddptr, *ddeptr;
off_t pos;
int fd2, incr, len, n, saved_errno, space;
len = 0;
space = 0;
buf = NULL;
ddptr = NULL;
/*
* Use the system page size if that is a multiple of DIRBLKSIZ.
* Hopefully this can be a big win someday by allowing page
* trades to user space to be done by _getdirentries().
*/
incr = getpagesize();
if ((incr % DIRBLKSIZ) != 0)
incr = DIRBLKSIZ;
/*
* The strategy here is to read all the directory
* entries into a buffer, sort the buffer, and
* remove duplicate entries by setting the inode
* number to zero.
*
* We reopen the directory because _getdirentries()
* on a MNT_UNION mount modifies the open directory,
* making it refer to the lower directory after the
* upper directory's entries are exhausted.
* This would otherwise break software that uses
* the directory descriptor for fchdir or *at
* functions, such as fts.c.
*/
if ((fd2 = _openat(dirp->dd_fd, ".", O_RDONLY | O_CLOEXEC)) == -1)
return (false);
if (use_current_pos) {
pos = lseek(dirp->dd_fd, 0, SEEK_CUR);
if (pos == -1 || lseek(fd2, pos, SEEK_SET) == -1) {
saved_errno = errno;
_close(fd2);
errno = saved_errno;
return (false);
}
}
do {
/*
* Always make at least DIRBLKSIZ bytes
* available to _getdirentries
*/
if (space < DIRBLKSIZ) {
space += incr;
len += incr;
buf = reallocf(buf, len);
if (buf == NULL) {
saved_errno = errno;
_close(fd2);
errno = saved_errno;
return (false);
}
ddptr = buf + (len - space);
}
n = _getdirentries(fd2, ddptr, space, &dirp->dd_seek);
if (n > 0) {
ddptr += n;
space -= n;
}
if (n < 0) {
saved_errno = errno;
_close(fd2);
errno = saved_errno;
return (false);
}
} while (n > 0);
_close(fd2);
ddeptr = ddptr;
/*
* There is now a buffer full of (possibly) duplicate
* names.
*/
dirp->dd_buf = buf;
/*
* Go round this loop twice...
*
* Scan through the buffer, counting entries.
* On the second pass, save pointers to each one.
* Then sort the pointers and remove duplicate names.
*/
for (dpv = 0;;) {
n = 0;
ddptr = buf;
while (ddptr < ddeptr) {
struct dirent *dp;
dp = (struct dirent *) ddptr;
if ((long)dp & 03L)
break;
if ((dp->d_reclen <= 0) ||
(dp->d_reclen > (ddeptr + 1 - ddptr)))
break;
ddptr += dp->d_reclen;
if (dp->d_fileno) {
if (dpv)
dpv[n] = dp;
n++;
}
}
if (dpv) {
struct dirent *xp;
/*
* This sort must be stable.
*/
mergesort(dpv, n, sizeof(*dpv), opendir_compar);
dpv[n] = NULL;
xp = NULL;
/*
* Scan through the buffer in sort order,
* zapping the inode number of any
* duplicate names.
*/
for (n = 0; dpv[n]; n++) {
struct dirent *dp = dpv[n];
if ((xp == NULL) ||
strcmp(dp->d_name, xp->d_name)) {
xp = dp;
} else {
dp->d_fileno = 0;
}
if (dp->d_type == DT_WHT &&
(dirp->dd_flags & DTF_HIDEW))
dp->d_fileno = 0;
}
free(dpv);
break;
} else {
dpv = malloc((n+1) * sizeof(struct dirent *));
if (dpv == NULL)
break;
}
}
dirp->dd_len = len;
dirp->dd_size = ddptr - dirp->dd_buf;
return (true);
}
