/* $NetBSD: opendir.c,v 1.12 1997/02/25 13:16:39 fvdl Exp $ */ /* * 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. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. 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) #if 0 static char sccsid[] = "@(#)opendir.c 8.7 (Berkeley) 12/10/94"; #else static char rcsid[] = "$NetBSD: opendir.c,v 1.12 1997/02/25 13:16:39 fvdl Exp $"; #endif #endif /* LIBC_SCCS and not lint */ #include #include #include #include #include #include #include #include #include /* * Open a directory. */ DIR * opendir(name) const char *name; { return (__opendir2(name, DTF_HIDEW|DTF_NODUP)); } DIR * __opendir2(name, flags) const char *name; int flags; { DIR *dirp; int fd; struct stat sb; int pagesz; int incr; int unionstack; if ((fd = open(name, O_RDONLY | O_NONBLOCK)) == -1) return (NULL); if (fstat(fd, &sb) || !S_ISDIR(sb.st_mode)) { errno = ENOTDIR; close(fd); return (NULL); } if (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1 || (dirp = (DIR *)malloc(sizeof(DIR))) == NULL) { close(fd); return (NULL); } /* * If the machine's page size is an exact multiple of DIRBLKSIZ, * use a buffer that is cluster boundary aligned. * Hopefully this can be a big win someday by allowing page trades * to user space to be done by getdirentries() */ if (((pagesz = getpagesize()) % DIRBLKSIZ) == 0) incr = pagesz; else 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) { free(dirp); close(fd); return (NULL); } unionstack = !(strncmp(sfb.f_fstypename, MOUNT_UNION, MFSNAMELEN)) || (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 = realloc(buf, len); if (buf == NULL) { free(dirp); close(fd); return (NULL); } 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)) == -1) { free(buf); free(dirp); 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;;) { for (n = 0, ddptr = buf; ddptr < ddeptr;) { struct dirent *dp; dp = (struct dirent *) ddptr; if ((long)dp & 03) 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), alphasort); 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_buf = malloc(dirp->dd_len); if (dirp->dd_buf == NULL) { free(dirp); close (fd); return (NULL); } dirp->dd_seek = 0; flags &= ~DTF_REWIND; } dirp->dd_loc = 0; dirp->dd_fd = fd; dirp->dd_flags = flags; /* * Set up seek point for rewinddir. */ dirp->dd_rewind = telldir(dirp); return (dirp); }