clamd/fts.c
9a1b6ef5
 /* File tree traversal functions.
    Copyright (C) 1994-2015 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.
 
    The GNU C Library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.
 
    You should have received a copy of the GNU Lesser General Public
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
 /*-
  * Copyright (c) 1990, 1993, 1994
  *	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.
  * 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)
 static char sccsid[] = "@(#)fts.c	8.6 (Berkeley) 8/14/94";
 #endif /* LIBC_SCCS and not lint */
 
21ef08e3
 #if HAVE_CONFIG_H
 #include "clamav-config.h"
 #endif
 
 #if defined(FANOTIFY) && defined(C_LINUX)
 
9a1b6ef5
 #include <sys/param.h>
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <dirent.h>
 #include <errno.h>
 #include "priv_fts.h"
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 
 #define FTS_OPEN _priv_fts_open
 #define FTS_CLOSE _priv_fts_close
 #define FTS_READ _priv_fts_read
 #define FTS_SET _priv_fts_set
 #define FTS_CHILDREN _priv_fts_children
 #define FTSOBJ FTS
 #define FTSENTRY FTSENT
 #define INO_T ino_t
 #define STAT stat
 #define LSTAT lstat
 
 #define internal_function
 # define __set_errno(val) (errno = (val))
 
 /* Largest alignment size needed, minus one.
    Usually long double is the worst case.  */
 #ifndef ALIGNBYTES
 #define ALIGNBYTES	(__alignof__ (long double) - 1)
 #endif
 /* Align P to that size.  */
 #ifndef ALIGN
 #define	ALIGN(p)	(((unsigned long int) (p) + ALIGNBYTES) & ~ALIGNBYTES)
 #endif
 
 /* Support for the LFS API version.  */
 #ifndef FTS_OPEN
 #define FTS_OPEN fts_open
 #define FTS_CLOSE fts_close
 #define FTS_READ fts_read
 #define FTS_SET fts_set
 #define FTS_CHILDREN fts_children
 # define FTSOBJ FTS
 # define FTSENTRY FTSENT
 # define INO_T ino_t
 # define STAT stat
 # define LSTAT lstat
 #endif
 
 static FTSENTRY	*fts_alloc (FTSOBJ *, const char *, size_t) internal_function;
 static FTSENTRY	*fts_build (FTSOBJ *, int) internal_function;
 static void	 fts_lfree (FTSENTRY *) internal_function;
 static void	 fts_load (FTSOBJ *, FTSENTRY *) internal_function;
 static size_t	 fts_maxarglen (char * const *) internal_function;
 static void	 fts_padjust (FTSOBJ *, FTSENTRY *) internal_function;
 static int	 fts_palloc (FTSOBJ *, size_t) internal_function;
 static FTSENTRY	*fts_sort (FTSOBJ *, FTSENTRY *, int) internal_function;
 static u_short	 fts_stat (FTSOBJ *, FTSENTRY *, int) internal_function;
 static int      fts_safe_changedir (FTSOBJ *, FTSENTRY *, int, const char *)
      internal_function;
 
 #ifndef MAX
 #define MAX(a, b)	({ __typeof__ (a) _a = (a); \
 			   __typeof__ (b) _b = (b); \
 			   _a > _b ? _a : _b; })
 #endif
 
 #define	ISDOT(a)	(a[0] == '.' && (!a[1] || (a[1] == '.' && !a[2])))
 
 #define CLR(opt)	(sp->fts_options &= ~(opt))
 #define	ISSET(opt)	(sp->fts_options & (opt))
 #define	SET(opt)	(sp->fts_options |= (opt))
 
 #define	FCHDIR(sp, fd)	(!ISSET(FTS_NOCHDIR) && fchdir(fd))
 
 /* fts_build flags */
 #define	BCHILD		1		/* fts_children */
 #define	BNAMES		2		/* fts_children, names only */
 #define	BREAD		3		/* fts_read */
 
 FTSOBJ *
 FTS_OPEN (char * const *argv, int options,
 	  int (*compar) (const FTSENTRY **, const FTSENTRY **))
 {
 	FTSOBJ *sp;
 	FTSENTRY *p, *root;
 	int nitems;
 	FTSENTRY *parent = NULL;
 	FTSENTRY *tmp;
 
 	/* Options check. */
 	if (options & ~FTS_OPTIONMASK) {
 		__set_errno (EINVAL);
 		return (NULL);
 	}
 
 	/* Allocate/initialize the stream */
 	if ((sp = malloc((u_int)sizeof(FTSOBJ))) == NULL)
 		return (NULL);
 	memset(sp, 0, sizeof(FTSOBJ));
 	sp->fts_compar = (int (*) (const void *, const void *)) compar;
 	sp->fts_options = options;
 
 	/* Logical walks turn on NOCHDIR; symbolic links are too hard. */
 	if (ISSET(FTS_LOGICAL))
 		SET(FTS_NOCHDIR);
 
 	/*
 	 * Start out with 1K of path space, and enough, in any case,
 	 * to hold the user's paths.
 	 */
 #ifndef MAXPATHLEN
 #define MAXPATHLEN 1024
 #endif
 	size_t maxarglen = fts_maxarglen(argv);
 	if (fts_palloc(sp, MAX(maxarglen, MAXPATHLEN)))
 		goto mem1;
 
 	/* Allocate/initialize root's parent. */
 	if (*argv != NULL) {
 		if ((parent = fts_alloc(sp, "", 0)) == NULL)
 			goto mem2;
 		parent->fts_level = FTS_ROOTPARENTLEVEL;
 	  }
 
 	/* Allocate/initialize root(s). */
 	for (root = NULL, nitems = 0; *argv != NULL; ++argv, ++nitems) {
 		/* Don't allow zero-length paths. */
 		size_t len = strlen(*argv);
 		if (len == 0) {
 			__set_errno (ENOENT);
 			goto mem3;
 		}
 
 		p = fts_alloc(sp, *argv, len);
 		p->fts_level = FTS_ROOTLEVEL;
 		p->fts_parent = parent;
 		p->fts_accpath = p->fts_name;
 		p->fts_info = fts_stat(sp, p, ISSET(FTS_COMFOLLOW));
 
 		/* Command-line "." and ".." are real directories. */
 		if (p->fts_info == FTS_DOT)
 			p->fts_info = FTS_D;
 
 		/*
 		 * If comparison routine supplied, traverse in sorted
 		 * order; otherwise traverse in the order specified.
 		 */
 		if (compar) {
 			p->fts_link = root;
 			root = p;
 		} else {
 			p->fts_link = NULL;
 			if (root == NULL)
 				tmp = root = p;
 			else {
 				tmp->fts_link = p;
 				tmp = p;
 			}
 		}
 	}
 	if (compar && nitems > 1)
 		root = fts_sort(sp, root, nitems);
 
 	/*
 	 * Allocate a dummy pointer and make fts_read think that we've just
 	 * finished the node before the root(s); set p->fts_info to FTS_INIT
 	 * so that everything about the "current" node is ignored.
 	 */
 	if ((sp->fts_cur = fts_alloc(sp, "", 0)) == NULL)
 		goto mem3;
 	sp->fts_cur->fts_link = root;
 	sp->fts_cur->fts_info = FTS_INIT;
 
 	/*
 	 * If using chdir(2), grab a file descriptor pointing to dot to ensure
 	 * that we can get back here; this could be avoided for some paths,
 	 * but almost certainly not worth the effort.  Slashes, symbolic links,
 	 * and ".." are all fairly nasty problems.  Note, if we can't get the
 	 * descriptor we run anyway, just more slowly.
 	 */
 	if (!ISSET(FTS_NOCHDIR)
 	    && (sp->fts_rfd = open(".", O_RDONLY, 0)) < 0)
 		SET(FTS_NOCHDIR);
 
 	return (sp);
 
 mem3:	fts_lfree(root);
 	free(parent);
 mem2:	free(sp->fts_path);
 mem1:	free(sp);
 	return (NULL);
 }
 
 static void
 internal_function
 fts_load (FTSOBJ *sp, FTSENTRY *p)
 {
 	int len;
 	char *cp;
 
 	/*
 	 * Load the stream structure for the next traversal.  Since we don't
 	 * actually enter the directory until after the preorder visit, set
 	 * the fts_accpath field specially so the chdir gets done to the right
 	 * place and the user can access the first node.  From fts_open it's
 	 * known that the path will fit.
 	 */
 	len = p->fts_pathlen = p->fts_namelen;
 	memmove(sp->fts_path, p->fts_name, len + 1);
 	if ((cp = strrchr(p->fts_name, '/')) && (cp != p->fts_name || cp[1])) {
 		len = strlen(++cp);
 		memmove(p->fts_name, cp, len + 1);
 		p->fts_namelen = len;
 	}
 	p->fts_accpath = p->fts_path = sp->fts_path;
 	sp->fts_dev = p->fts_dev;
 }
 
 int
 FTS_CLOSE (FTSOBJ *sp)
 {
 	FTSENTRY *freep, *p;
 	int saved_errno;
 
 	/*
 	 * This still works if we haven't read anything -- the dummy structure
 	 * points to the root list, so we step through to the end of the root
 	 * list which has a valid parent pointer.
 	 */
 	if (sp->fts_cur) {
 		for (p = sp->fts_cur; p->fts_level >= FTS_ROOTLEVEL;) {
 			freep = p;
 			p = p->fts_link != NULL ? p->fts_link : p->fts_parent;
 			free(freep);
 		}
 		free(p);
 	}
 
 	/* Free up child linked list, sort array, path buffer. */
 	if (sp->fts_child)
 		fts_lfree(sp->fts_child);
 	free(sp->fts_array);
 	free(sp->fts_path);
 
 	/* Return to original directory, save errno if necessary. */
 	if (!ISSET(FTS_NOCHDIR)) {
 		saved_errno = fchdir(sp->fts_rfd) ? errno : 0;
 		(void)close(sp->fts_rfd);
 
 		/* Set errno and return. */
 		if (saved_errno != 0) {
 			/* Free up the stream pointer. */
 			free(sp);
 			__set_errno (saved_errno);
 			return (-1);
 		}
 	}
 
 	/* Free up the stream pointer. */
 	free(sp);
 	return (0);
 }
 
 /*
  * Special case of "/" at the end of the path so that slashes aren't
  * appended which would cause paths to be written as "....//foo".
  */
 #define	NAPPEND(p)							\
 	(p->fts_path[p->fts_pathlen - 1] == '/'				\
 	    ? p->fts_pathlen - 1 : p->fts_pathlen)
 
 FTSENTRY *
 FTS_READ (FTSOBJ *sp)
 {
 	FTSENTRY *p, *tmp;
 	int instr;
 	char *t;
 	int saved_errno;
 
 	/* If finished or unrecoverable error, return NULL. */
 	if (sp->fts_cur == NULL || ISSET(FTS_STOP))
 		return (NULL);
 
 	/* Set current node pointer. */
 	p = sp->fts_cur;
 
 	/* Save and zero out user instructions. */
 	instr = p->fts_instr;
 	p->fts_instr = FTS_NOINSTR;
 
 	/* Any type of file may be re-visited; re-stat and re-turn. */
 	if (instr == FTS_AGAIN) {
 		p->fts_info = fts_stat(sp, p, 0);
 		return (p);
 	}
 
 	/*
 	 * Following a symlink -- SLNONE test allows application to see
 	 * SLNONE and recover.  If indirecting through a symlink, have
 	 * keep a pointer to current location.  If unable to get that
 	 * pointer, follow fails.
 	 */
 	if (instr == FTS_FOLLOW &&
 	    (p->fts_info == FTS_SL || p->fts_info == FTS_SLNONE)) {
 		p->fts_info = fts_stat(sp, p, 1);
 		if (p->fts_info == FTS_D && !ISSET(FTS_NOCHDIR)) {
 			if ((p->fts_symfd = open(".", O_RDONLY, 0)) < 0) {
 				p->fts_errno = errno;
 				p->fts_info = FTS_ERR;
 			} else
 				p->fts_flags |= FTS_SYMFOLLOW;
 		}
 		return (p);
 	}
 
 	/* Directory in pre-order. */
 	if (p->fts_info == FTS_D) {
 		/* If skipped or crossed mount point, do post-order visit. */
 		if (instr == FTS_SKIP ||
 		    (ISSET(FTS_XDEV) && p->fts_dev != sp->fts_dev)) {
 			if (p->fts_flags & FTS_SYMFOLLOW)
 				(void)close(p->fts_symfd);
 			if (sp->fts_child) {
 				fts_lfree(sp->fts_child);
 				sp->fts_child = NULL;
 			}
 			p->fts_info = FTS_DP;
 			return (p);
 		}
 
 		/* Rebuild if only read the names and now traversing. */
 		if (sp->fts_child != NULL && ISSET(FTS_NAMEONLY)) {
 			CLR(FTS_NAMEONLY);
 			fts_lfree(sp->fts_child);
 			sp->fts_child = NULL;
 		}
 
 		/*
 		 * Cd to the subdirectory.
 		 *
 		 * If have already read and now fail to chdir, whack the list
 		 * to make the names come out right, and set the parent errno
 		 * so the application will eventually get an error condition.
 		 * Set the FTS_DONTCHDIR flag so that when we logically change
 		 * directories back to the parent we don't do a chdir.
 		 *
 		 * If haven't read do so.  If the read fails, fts_build sets
 		 * FTS_STOP or the fts_info field of the node.
 		 */
 		if (sp->fts_child != NULL) {
 			if (fts_safe_changedir(sp, p, -1, p->fts_accpath)) {
 				p->fts_errno = errno;
 				p->fts_flags |= FTS_DONTCHDIR;
 				for (p = sp->fts_child; p != NULL;
 				     p = p->fts_link)
 					p->fts_accpath =
 					    p->fts_parent->fts_accpath;
 			}
 		} else if ((sp->fts_child = fts_build(sp, BREAD)) == NULL) {
 			if (ISSET(FTS_STOP))
 				return (NULL);
 			return (p);
 		}
 		p = sp->fts_child;
 		sp->fts_child = NULL;
 		sp->fts_cur = p;
 		goto name;
 	}
 
 	/* Move to the next node on this level. */
 next:	tmp = p;
 	if ((p = p->fts_link) != NULL) {
 		sp->fts_cur = p;
 		free(tmp);
 
 		/*
 		 * If reached the top, return to the original directory (or
 		 * the root of the tree), and load the paths for the next root.
 		 */
 		if (p->fts_level == FTS_ROOTLEVEL) {
 			if (FCHDIR(sp, sp->fts_rfd)) {
 				SET(FTS_STOP);
 				return (NULL);
 			}
 			fts_load(sp, p);
 			return p;
 		}
 
 		/*
 		 * User may have called fts_set on the node.  If skipped,
 		 * ignore.  If followed, get a file descriptor so we can
 		 * get back if necessary.
 		 */
 		if (p->fts_instr == FTS_SKIP)
 			goto next;
 		if (p->fts_instr == FTS_FOLLOW) {
 			p->fts_info = fts_stat(sp, p, 1);
 			if (p->fts_info == FTS_D && !ISSET(FTS_NOCHDIR)) {
 				if ((p->fts_symfd =
 				    open(".", O_RDONLY, 0)) < 0) {
 					p->fts_errno = errno;
 					p->fts_info = FTS_ERR;
 				} else
 					p->fts_flags |= FTS_SYMFOLLOW;
 			}
 			p->fts_instr = FTS_NOINSTR;
 		}
 
 name:		t = sp->fts_path + NAPPEND(p->fts_parent);
 		*t++ = '/';
 		memmove(t, p->fts_name, p->fts_namelen + 1);
 		return p;
 	}
 
 	/* Move up to the parent node. */
 	p = tmp->fts_parent;
 	sp->fts_cur = p;
 	free(tmp);
 
 	if (p->fts_level == FTS_ROOTPARENTLEVEL) {
 		/*
 		 * Done; free everything up and set errno to 0 so the user
 		 * can distinguish between error and EOF.
 		 */
 		free(p);
 		__set_errno (0);
 		return (sp->fts_cur = NULL);
 	}
 
 	/* NUL terminate the pathname. */
 	sp->fts_path[p->fts_pathlen] = '\0';
 
 	/*
 	 * Return to the parent directory.  If at a root node or came through
 	 * a symlink, go back through the file descriptor.  Otherwise, cd up
 	 * one directory.
 	 */
 	if (p->fts_level == FTS_ROOTLEVEL) {
 		if (FCHDIR(sp, sp->fts_rfd)) {
 			SET(FTS_STOP);
 			return (NULL);
 		}
 	} else if (p->fts_flags & FTS_SYMFOLLOW) {
 		if (FCHDIR(sp, p->fts_symfd)) {
 			saved_errno = errno;
 			(void)close(p->fts_symfd);
 			__set_errno (saved_errno);
 			SET(FTS_STOP);
 			return (NULL);
 		}
 		(void)close(p->fts_symfd);
 	} else if (!(p->fts_flags & FTS_DONTCHDIR) &&
 		   fts_safe_changedir(sp, p->fts_parent, -1, "..")) {
 		SET(FTS_STOP);
 		return (NULL);
 	}
 	p->fts_info = p->fts_errno ? FTS_ERR : FTS_DP;
 	return p;
 }
 
 /*
  * Fts_set takes the stream as an argument although it's not used in this
  * implementation; it would be necessary if anyone wanted to add global
  * semantics to fts using fts_set.  An error return is allowed for similar
  * reasons.
  */
 /* ARGSUSED */
 int
 FTS_SET (FTSOBJ *sp, FTSENTRY *p, int instr)
 {
 	if (instr != 0 && instr != FTS_AGAIN && instr != FTS_FOLLOW &&
 	    instr != FTS_NOINSTR && instr != FTS_SKIP) {
 		__set_errno (EINVAL);
 		return (1);
 	}
 	p->fts_instr = instr;
 	return (0);
 }
 
 FTSENTRY *
 FTS_CHILDREN(FTSOBJ *sp, int instr)
 {
 	FTSENTRY *p;
 	int fd;
 
 	if (instr != 0 && instr != FTS_NAMEONLY) {
 		__set_errno (EINVAL);
 		return (NULL);
 	}
 
 	/* Set current node pointer. */
 	p = sp->fts_cur;
 
 	/*
 	 * Errno set to 0 so user can distinguish empty directory from
 	 * an error.
 	 */
 	__set_errno (0);
 
 	/* Fatal errors stop here. */
 	if (ISSET(FTS_STOP))
 		return (NULL);
 
 	/* Return logical hierarchy of user's arguments. */
 	if (p->fts_info == FTS_INIT)
 		return (p->fts_link);
 
 	/*
 	 * If not a directory being visited in pre-order, stop here.  Could
 	 * allow FTS_DNR, assuming the user has fixed the problem, but the
 	 * same effect is available with FTS_AGAIN.
 	 */
 	if (p->fts_info != FTS_D /* && p->fts_info != FTS_DNR */)
 		return (NULL);
 
 	/* Free up any previous child list. */
 	if (sp->fts_child != NULL)
 		fts_lfree(sp->fts_child);
 
 	if (instr == FTS_NAMEONLY) {
 		SET(FTS_NAMEONLY);
 		instr = BNAMES;
 	} else
 		instr = BCHILD;
 
 	/*
 	 * If using chdir on a relative path and called BEFORE fts_read does
 	 * its chdir to the root of a traversal, we can lose -- we need to
 	 * chdir into the subdirectory, and we don't know where the current
 	 * directory is, so we can't get back so that the upcoming chdir by
 	 * fts_read will work.
 	 */
 	if (p->fts_level != FTS_ROOTLEVEL || p->fts_accpath[0] == '/' ||
 	    ISSET(FTS_NOCHDIR))
 		return (sp->fts_child = fts_build(sp, instr));
 
 	if ((fd = open(".", O_RDONLY, 0)) < 0)
 		return (NULL);
 	sp->fts_child = fts_build(sp, instr);
 	if (fchdir(fd))
 		return (NULL);
 	(void)close(fd);
 	return (sp->fts_child);
 }
 
 static inline int
 dirent_not_directory(const struct dirent *dp)
 {
 #if defined DT_DIR && defined _DIRENT_HAVE_D_TYPE
         return dp->d_type != DT_DIR && dp->d_type != DT_UNKNOWN;
 #else
         return 0;
 #endif
 }
 
 /*
  * This is the tricky part -- do not casually change *anything* in here.  The
  * idea is to build the linked list of entries that are used by fts_children
  * and fts_read.  There are lots of special cases.
  *
  * The real slowdown in walking the tree is the stat calls.  If FTS_NOSTAT is
  * set and it's a physical walk (so that symbolic links can't be directories),
  * we can do things quickly.  First, if it's a 4.4BSD file system, the type
  * of the file is in the directory entry.  Otherwise, we assume that the number
  * of subdirectories in a node is equal to the number of links to the parent.
  * The former skips all stat calls.  The latter skips stat calls in any leaf
  * directories and for any files after the subdirectories in the directory have
  * been found, cutting the stat calls by about 2/3.
  */
 static FTSENTRY *
 internal_function
 fts_build (FTSOBJ *sp, int type)
 {
 	struct dirent *dp;
 	FTSENTRY *p, *head;
 	int nitems;
 	FTSENTRY *cur, *tail;
 	DIR *dirp;
 	void *oldaddr;
 	int cderrno, descend, len, level, nlinks, saved_errno,
 	    nostat, doadjust;
 	size_t maxlen;
 	char *cp;
 
 	/* Set current node pointer. */
 	cur = sp->fts_cur;
 
 	/*
 	 * Open the directory for reading.  If this fails, we're done.
 	 * If being called from fts_read, set the fts_info field.
 	 */
 #if defined FTS_WHITEOUT && 0
 	if (ISSET(FTS_WHITEOUT))
 		oflag = DTF_NODUP|DTF_REWIND;
 	else
 		oflag = DTF_HIDEW|DTF_NODUP|DTF_REWIND;
 #else
 # define __opendir2(path, flag) opendir(path)
 #endif
        if ((dirp = __opendir2(cur->fts_accpath, oflag)) == NULL) {
 		if (type == BREAD) {
 			cur->fts_info = FTS_DNR;
 			cur->fts_errno = errno;
 		}
 		return (NULL);
 	}
 
 	/*
 	 * Nlinks is the number of possible entries of type directory in the
 	 * directory if we're cheating on stat calls, 0 if we're not doing
 	 * any stat calls at all, -1 if we're doing stats on everything.
 	 */
 	if (type == BNAMES) {
 		nlinks = 0;
 		/* Be quiet about nostat, GCC. */
 		nostat = 0;
 	} else if (ISSET(FTS_NOSTAT) && ISSET(FTS_PHYSICAL)) {
 		nlinks = cur->fts_nlink - (ISSET(FTS_SEEDOT) ? 0 : 2);
 		nostat = 1;
 	} else {
 		nlinks = -1;
 		nostat = 0;
 	}
 
 #ifdef notdef
 	(void)printf("nlinks == %d (cur: %d)\n", nlinks, cur->fts_nlink);
 	(void)printf("NOSTAT %d PHYSICAL %d SEEDOT %d\n",
 	    ISSET(FTS_NOSTAT), ISSET(FTS_PHYSICAL), ISSET(FTS_SEEDOT));
 #endif
 	/*
 	 * If we're going to need to stat anything or we want to descend
 	 * and stay in the directory, chdir.  If this fails we keep going,
 	 * but set a flag so we don't chdir after the post-order visit.
 	 * We won't be able to stat anything, but we can still return the
 	 * names themselves.  Note, that since fts_read won't be able to
 	 * chdir into the directory, it will have to return different path
 	 * names than before, i.e. "a/b" instead of "b".  Since the node
 	 * has already been visited in pre-order, have to wait until the
 	 * post-order visit to return the error.  There is a special case
 	 * here, if there was nothing to stat then it's not an error to
 	 * not be able to stat.  This is all fairly nasty.  If a program
 	 * needed sorted entries or stat information, they had better be
 	 * checking FTS_NS on the returned nodes.
 	 */
 	cderrno = 0;
 	if (nlinks || type == BREAD) {
 		if (fts_safe_changedir(sp, cur, dirfd(dirp), NULL)) {
 			if (nlinks && type == BREAD)
 				cur->fts_errno = errno;
 			cur->fts_flags |= FTS_DONTCHDIR;
 			descend = 0;
 			cderrno = errno;
 			(void)closedir(dirp);
 			dirp = NULL;
 		} else
 			descend = 1;
 	} else
 		descend = 0;
 
 	/*
 	 * Figure out the max file name length that can be stored in the
 	 * current path -- the inner loop allocates more path as necessary.
 	 * We really wouldn't have to do the maxlen calculations here, we
 	 * could do them in fts_read before returning the path, but it's a
 	 * lot easier here since the length is part of the dirent structure.
 	 *
 	 * If not changing directories set a pointer so that can just append
 	 * each new name into the path.
 	 */
 	len = NAPPEND(cur);
 	if (ISSET(FTS_NOCHDIR)) {
 		cp = sp->fts_path + len;
 		*cp++ = '/';
 	} else {
 		/* GCC, you're too verbose. */
 		cp = NULL;
 	}
 	len++;
 	maxlen = sp->fts_pathlen - len;
 
 	level = cur->fts_level + 1;
 
 	/* Read the directory, attaching each entry to the `link' pointer. */
 	doadjust = 0;
 	for (head = tail = NULL, nitems = 0; dirp && (dp = readdir(dirp));) {
 		if (!ISSET(FTS_SEEDOT) && ISDOT(dp->d_name))
 			continue;
 
 		if ((p = fts_alloc(sp, dp->d_name, _D_EXACT_NAMLEN (dp))) == NULL)
 			goto mem1;
 		if (_D_EXACT_NAMLEN (dp) >= maxlen) {/* include space for NUL */
 			oldaddr = sp->fts_path;
 			if (fts_palloc(sp, _D_EXACT_NAMLEN (dp) + len + 1)) {
 				/*
 				 * No more memory for path or structures.  Save
 				 * errno, free up the current structure and the
 				 * structures already allocated.
 				 */
 mem1:				saved_errno = errno;
 				free(p);
 				fts_lfree(head);
 				(void)closedir(dirp);
 				cur->fts_info = FTS_ERR;
 				SET(FTS_STOP);
 				__set_errno (saved_errno);
 				return (NULL);
 			}
 			/* Did realloc() change the pointer? */
 			if (oldaddr != sp->fts_path) {
 				doadjust = 1;
 				if (ISSET(FTS_NOCHDIR))
 					cp = sp->fts_path + len;
 			}
 			maxlen = sp->fts_pathlen - len;
 		}
 
 		if (len + _D_EXACT_NAMLEN (dp) >= USHRT_MAX) {
 			/*
 			 * In an FTSENT, fts_pathlen is a u_short so it is
 			 * possible to wraparound here.  If we do, free up
 			 * the current structure and the structures already
 			 * allocated, then error out with ENAMETOOLONG.
 			 */
 			free(p);
 			fts_lfree(head);
 			(void)closedir(dirp);
 			cur->fts_info = FTS_ERR;
 			SET(FTS_STOP);
 			__set_errno (ENAMETOOLONG);
 			return (NULL);
 		}
 		p->fts_level = level;
 		p->fts_parent = sp->fts_cur;
 		p->fts_pathlen = len + _D_EXACT_NAMLEN (dp);
 
 #if defined FTS_WHITEOUT && 0
 		if (dp->d_type == DT_WHT)
 			p->fts_flags |= FTS_ISW;
 #endif
 
 		/* Unreachable code.  cderrno is only ever set to a nonnull
 		   value if dirp is closed at the same time.  But then we
 		   cannot enter this loop.  */
 		if (0 && cderrno) {
 			if (nlinks) {
 				p->fts_info = FTS_NS;
 				p->fts_errno = cderrno;
 			} else
 				p->fts_info = FTS_NSOK;
 			p->fts_accpath = cur->fts_accpath;
 		} else if (nlinks == 0
                            || (nostat && dirent_not_directory(dp))) {
 			p->fts_accpath =
 			    ISSET(FTS_NOCHDIR) ? p->fts_path : p->fts_name;
 			p->fts_info = FTS_NSOK;
 		} else {
 			/* Build a file name for fts_stat to stat. */
 			if (ISSET(FTS_NOCHDIR)) {
 				p->fts_accpath = p->fts_path;
 				memmove(cp, p->fts_name, p->fts_namelen + 1);
 			} else
 				p->fts_accpath = p->fts_name;
 			/* Stat it. */
 			p->fts_info = fts_stat(sp, p, 0);
 
 			/* Decrement link count if applicable. */
 			if (nlinks > 0 && (p->fts_info == FTS_D ||
 			    p->fts_info == FTS_DC || p->fts_info == FTS_DOT))
 				--nlinks;
 		}
 
 		/* We walk in directory order so "ls -f" doesn't get upset. */
 		p->fts_link = NULL;
 		if (head == NULL)
 			head = tail = p;
 		else {
 			tail->fts_link = p;
 			tail = p;
 		}
 		++nitems;
 	}
 	if (dirp)
 		(void)closedir(dirp);
 
 	/*
 	 * If realloc() changed the address of the path, adjust the
 	 * addresses for the rest of the tree and the dir list.
 	 */
 	if (doadjust)
 		fts_padjust(sp, head);
 
 	/*
 	 * If not changing directories, reset the path back to original
 	 * state.
 	 */
 	if (ISSET(FTS_NOCHDIR)) {
 		if (len == sp->fts_pathlen || nitems == 0)
 			--cp;
 		*cp = '\0';
 	}
 
 	/*
 	 * If descended after called from fts_children or after called from
 	 * fts_read and nothing found, get back.  At the root level we use
 	 * the saved fd; if one of fts_open()'s arguments is a relative path
 	 * to an empty directory, we wind up here with no other way back.  If
 	 * can't get back, we're done.
 	 */
 	if (descend && (type == BCHILD || !nitems) &&
 	    (cur->fts_level == FTS_ROOTLEVEL ?
 	     FCHDIR(sp, sp->fts_rfd) :
 	     fts_safe_changedir(sp, cur->fts_parent, -1, ".."))) {
 		cur->fts_info = FTS_ERR;
 		SET(FTS_STOP);
 		fts_lfree(head);
 		return (NULL);
 	}
 
 	/* If didn't find anything, return NULL. */
 	if (!nitems) {
 		if (type == BREAD)
 			cur->fts_info = FTS_DP;
 		fts_lfree(head);
 		return (NULL);
 	}
 
 	/* Sort the entries. */
 	if (sp->fts_compar && nitems > 1)
 		head = fts_sort(sp, head, nitems);
 	return (head);
 }
 
 static u_short
 internal_function
 fts_stat (FTSOBJ *sp, FTSENTRY *p, int follow)
 {
 	FTSENTRY *t;
 	dev_t dev;
 	INO_T ino;
 	struct STAT *sbp, sb;
 	int saved_errno;
 
 	/* If user needs stat info, stat buffer already allocated. */
 	sbp = ISSET(FTS_NOSTAT) ? &sb : p->fts_statp;
 
 #if defined FTS_WHITEOUT && 0
 	/* check for whiteout */
 	if (p->fts_flags & FTS_ISW) {
 		if (sbp != &sb) {
 			memset(sbp, '\0', sizeof (*sbp));
 			sbp->st_mode = S_IFWHT;
 		}
 		return (FTS_W);
        }
 #endif
 
 	/*
 	 * If doing a logical walk, or application requested FTS_FOLLOW, do
 	 * a stat(2).  If that fails, check for a non-existent symlink.  If
 	 * fail, set the errno from the stat call.
 	 */
 	if (ISSET(FTS_LOGICAL) || follow) {
 		if (STAT(p->fts_accpath, sbp)) {
 			saved_errno = errno;
 			if (!LSTAT(p->fts_accpath, sbp)) {
 				__set_errno (0);
 				return (FTS_SLNONE);
 			}
 			p->fts_errno = saved_errno;
 			goto err;
 		}
 	} else if (LSTAT(p->fts_accpath, sbp)) {
 		p->fts_errno = errno;
 err:		memset(sbp, 0, sizeof(struct STAT));
 		return (FTS_NS);
 	}
 
 	if (S_ISDIR(sbp->st_mode)) {
 		/*
 		 * Set the device/inode.  Used to find cycles and check for
 		 * crossing mount points.  Also remember the link count, used
 		 * in fts_build to limit the number of stat calls.  It is
 		 * understood that these fields are only referenced if fts_info
 		 * is set to FTS_D.
 		 */
 		dev = p->fts_dev = sbp->st_dev;
 		ino = p->fts_ino = sbp->st_ino;
 		p->fts_nlink = sbp->st_nlink;
 
 		if (ISDOT(p->fts_name))
 			return (FTS_DOT);
 
 		/*
 		 * Cycle detection is done by brute force when the directory
 		 * is first encountered.  If the tree gets deep enough or the
 		 * number of symbolic links to directories is high enough,
 		 * something faster might be worthwhile.
 		 */
 		for (t = p->fts_parent;
 		    t->fts_level >= FTS_ROOTLEVEL; t = t->fts_parent)
 			if (ino == t->fts_ino && dev == t->fts_dev) {
 				p->fts_cycle = t;
 				return (FTS_DC);
 			}
 		return (FTS_D);
 	}
 	if (S_ISLNK(sbp->st_mode))
 		return (FTS_SL);
 	if (S_ISREG(sbp->st_mode))
 		return (FTS_F);
 	return (FTS_DEFAULT);
 }
 
 static FTSENTRY *
 internal_function
 fts_sort (FTSOBJ *sp, FTSENTRY *head, int nitems)
 {
 	FTSENTRY **ap, *p;
 
 	/*
 	 * Construct an array of pointers to the structures and call qsort(3).
 	 * Reassemble the array in the order returned by qsort.  If unable to
 	 * sort for memory reasons, return the directory entries in their
 	 * current order.  Allocate enough space for the current needs plus
 	 * 40 so don't realloc one entry at a time.
 	 */
 	if (nitems > sp->fts_nitems) {
 		FTSENTRY **a;
 
 		sp->fts_nitems = nitems + 40;
 		if ((a = realloc(sp->fts_array,
 		    (size_t)(sp->fts_nitems * sizeof(FTSENTRY *)))) == NULL) {
 			free(sp->fts_array);
 			sp->fts_array = NULL;
 			sp->fts_nitems = 0;
 			return (head);
 		}
 		sp->fts_array = a;
 	}
 	for (ap = sp->fts_array, p = head; p; p = p->fts_link)
 		*ap++ = p;
 	qsort((void *)sp->fts_array, nitems, sizeof(FTSENTRY *), sp->fts_compar);
 	for (head = *(ap = sp->fts_array); --nitems; ++ap)
 		ap[0]->fts_link = ap[1];
 	ap[0]->fts_link = NULL;
 	return (head);
 }
 
 static FTSENTRY *
 internal_function
 fts_alloc (FTSOBJ *sp, const char *name, size_t namelen)
 {
 	FTSENTRY *p;
 	size_t len;
 
 	/*
 	 * The file name is a variable length array and no stat structure is
 	 * necessary if the user has set the nostat bit.  Allocate the FTSENT
 	 * structure, the file name and the stat structure in one chunk, but
 	 * be careful that the stat structure is reasonably aligned.  Since the
 	 * fts_name field is declared to be of size 1, the fts_name pointer is
 	 * namelen + 2 before the first possible address of the stat structure.
 	 */
 	len = sizeof(FTSENTRY) + namelen;
 	if (!ISSET(FTS_NOSTAT))
 		len += sizeof(struct STAT) + ALIGNBYTES;
 	if ((p = malloc(len)) == NULL)
 		return (NULL);
 
 	/* Copy the name and guarantee NUL termination. */
 	memmove(p->fts_name, name, namelen);
 	p->fts_name[namelen] = '\0';
 
 	if (!ISSET(FTS_NOSTAT))
 		p->fts_statp = (struct STAT *)ALIGN(p->fts_name + namelen + 2);
 	p->fts_namelen = namelen;
 	p->fts_path = sp->fts_path;
 	p->fts_errno = 0;
 	p->fts_flags = 0;
 	p->fts_instr = FTS_NOINSTR;
 	p->fts_number = 0;
 	p->fts_pointer = NULL;
 	return (p);
 }
 
 static void
 internal_function
 fts_lfree (FTSENTRY *head)
 {
 	FTSENTRY *p;
 
 	/* Free a linked list of structures. */
 	while ((p = head)) {
 		head = head->fts_link;
 		free(p);
 	}
 }
 
 /*
  * Allow essentially unlimited paths; find, rm, ls should all work on any tree.
  * Most systems will allow creation of paths much longer than MAXPATHLEN, even
  * though the kernel won't resolve them.  Add the size (not just what's needed)
  * plus 256 bytes so don't realloc the path 2 bytes at a time.
  */
 static int
 internal_function
 fts_palloc (FTSOBJ *sp, size_t more)
 {
 	char *p;
 
 	sp->fts_pathlen += more + 256;
 	/*
 	 * Check for possible wraparound.  In an FTS, fts_pathlen is
 	 * a signed int but in an FTSENT it is an unsigned short.
 	 * We limit fts_pathlen to USHRT_MAX to be safe in both cases.
 	 */
 	if (sp->fts_pathlen < 0 || sp->fts_pathlen >= USHRT_MAX) {
 		free(sp->fts_path);
 		sp->fts_path = NULL;
 		__set_errno (ENAMETOOLONG);
 		return (1);
 	}
 	p = realloc(sp->fts_path, sp->fts_pathlen);
 	if (p == NULL) {
 		free(sp->fts_path);
 		sp->fts_path = NULL;
 		return 1;
 	}
 	sp->fts_path = p;
 	return 0;
 }
 
 /*
  * When the path is realloc'd, have to fix all of the pointers in structures
  * already returned.
  */
 static void
 internal_function
 fts_padjust (FTSOBJ *sp, FTSENTRY *head)
 {
 	FTSENTRY *p;
 	char *addr = sp->fts_path;
 
 #define	ADJUST(p) do {							\
 	if ((p)->fts_accpath != (p)->fts_name) {			\
 		(p)->fts_accpath =					\
 		    (char *)addr + ((p)->fts_accpath - (p)->fts_path);	\
 	}								\
 	(p)->fts_path = addr;						\
 } while (0)
 	/* Adjust the current set of children. */
 	for (p = sp->fts_child; p; p = p->fts_link)
 		ADJUST(p);
 
 	/* Adjust the rest of the tree, including the current level. */
 	for (p = head; p->fts_level >= FTS_ROOTLEVEL;) {
 		ADJUST(p);
 		p = p->fts_link ? p->fts_link : p->fts_parent;
 	}
 }
 
 static size_t
 internal_function
 fts_maxarglen (char * const *argv)
 {
 	size_t len, max;
 
 	for (max = 0; *argv; ++argv)
 		if ((len = strlen(*argv)) > max)
 			max = len;
 	return (max + 1);
 }
 
 /*
  * Change to dir specified by fd or p->fts_accpath without getting
  * tricked by someone changing the world out from underneath us.
  * Assumes p->fts_dev and p->fts_ino are filled in.
  */
 static int
 internal_function
 fts_safe_changedir (FTSOBJ *sp, FTSENTRY *p, int fd, const char *path)
 {
 	int ret, oerrno, newfd;
 	struct stat sb;
 
 	newfd = fd;
 	if (ISSET(FTS_NOCHDIR))
 		return (0);
 	if (fd < 0 && (newfd = open(path, O_RDONLY, 0)) < 0)
 		return (-1);
 	if (fstat(newfd, &sb)) {
 		ret = -1;
 		goto bail;
 	}
 	if (p->fts_dev != sb.st_dev || p->fts_ino != sb.st_ino) {
 		__set_errno (ENOENT);		/* disinformation */
 		ret = -1;
 		goto bail;
 	}
 	ret = fchdir(newfd);
 bail:
 	oerrno = errno;
 	if (fd < 0)
 		(void)close(newfd);
 	__set_errno (oerrno);
 	return (ret);
 }
21ef08e3
 #endif