/*- * Copyright (c) 1983, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #if defined(LIBC_SCCS) && !defined(lint) static char sccsid[] = "@(#)opendir.c 8.8 (Berkeley) 5/1/95"; #endif /* LIBC_SCCS and not lint */ #include __FBSDID("$FreeBSD$"); #include "namespace.h" #include #include #include #include #include #include #include #include #include #include "un-namespace.h" #include "gen-private.h" #include "telldir.h" static DIR * __opendir_common(int, int, bool); /* * Open a directory. */ DIR * opendir(const char *name) { return (__opendir2(name, DTF_HIDEW|DTF_NODUP)); } /* * Open a directory with existing file descriptor. */ DIR * fdopendir(int fd) { if (_fcntl(fd, F_SETFD, FD_CLOEXEC) == -1) return (NULL); return (__opendir_common(fd, DTF_HIDEW|DTF_NODUP, true)); } DIR * __opendir2(const char *name, int flags) { int fd; DIR *dir; int saved_errno; if ((flags & (__DTF_READALL | __DTF_SKIPREAD)) != 0) return (NULL); if ((fd = _open(name, O_RDONLY | O_NONBLOCK | O_DIRECTORY | O_CLOEXEC)) == -1) return (NULL); dir = __opendir_common(fd, flags, false); if (dir == NULL) { saved_errno = errno; _close(fd); errno = saved_errno; } return (dir); } static int opendir_compar(const void *p1, const void *p2) { return (strcmp((*(const struct dirent **)p1)->d_name, (*(const struct dirent **)p2)->d_name)); } /* * 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 = NULL;;) { 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); } /* * 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); }