Merge in the safe chdir changes from Todd Miller's mods to the OpenBSD

tree.  Also merge in fix to NetBSD PR #1495.  These represent 1.3-1.9 in
the OpenBSD tree.  Make minor KNF changes to new code (which is in the
OpenBSD as 1.10).  This avoids the symlink race problems.

These patches should go into 2.2.5 before the ship if they don't
break anything in -current.
Reviewed by:	Bruce Evans
Obtained from:	OpenBSD

1 files changed, 64 insertions, 20 deletions

diff --git a/lib/libc/gen/fts-compat.c b/lib/libc/gen/fts-compat.c
index e532707..938dcb5 100644
--- a/lib/libc/gen/fts-compat.c
+++ b/lib/libc/gen/fts-compat.c
@@ -1,3 +1,5 @@
+/*	$OpenBSD: fts.c,v 1.9 1997/08/02 00:13:49 millert Exp $	*/
+
 /*-
  * Copyright (c) 1990, 1993, 1994
  *	The Regents of the University of California.  All rights reserved.
@@ -55,11 +57,13 @@ static void	 fts_padjust __P((FTS *, void *));
 static int	 fts_palloc __P((FTS *, size_t));
 static FTSENT	*fts_sort __P((FTS *, FTSENT *, int));
 static u_short	 fts_stat __P((FTS *, FTSENT *, int));
+static int	 fts_safe_changedir __P((FTS *, FTSENT *, int));
 
-#define	ISDOT(a)	(a[0] == '.' && (!a[1] || (a[1] == '.' && !a[2])) )
+#define	ISDOT(a)	(a[0] == '.' && (!a[1] || (a[1] == '.' && !a[2])))
 
-#define	ISSET(opt)	(sp->fts_options & opt)
-#define	SET(opt)	(sp->fts_options |= opt)
+#define	CLR(opt)	(sp->fts_options &= ~(opt))
+#define	ISSET(opt)	(sp->fts_options & (opt))
+#define	SET(opt)	(sp->fts_options |= (opt))
 
 #define	CHDIR(sp, path)	(!ISSET(FTS_NOCHDIR) && chdir(path))
 #define	FCHDIR(sp, fd)	(!ISSET(FTS_NOCHDIR) && fchdir(fd))
@@ -73,7 +77,7 @@ FTS *
 fts_open(argv, options, compar)
 	char * const *argv;
 	register int options;
-	int (*compar)();
+	int (*compar) __P((const FTSENT **, const FTSENT **));
 {
 	register FTS *sp;
 	register FTSENT *p, *root;
@@ -249,12 +253,12 @@ fts_close(sp)
 }
 
 /*
- * Special case a root of "/" so that slashes aren't appended which would
- * cause paths to be written as "//foo".
+ * 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_level == FTS_ROOTLEVEL && p->fts_pathlen == 1 &&	\
-	    p->fts_path[0] == '/' ? 0 : p->fts_pathlen)
+	(p->fts_path[p->fts_pathlen - 1] == '/'				\
+	    ? p->fts_pathlen - 1 : p->fts_pathlen)
 
 FTSENT *
 fts_read(sp)
@@ -304,7 +308,7 @@ fts_read(sp)
 	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) ) {
+		    (ISSET(FTS_XDEV) && p->fts_dev != sp->fts_dev)) {
 			if (p->fts_flags & FTS_SYMFOLLOW)
 				(void)close(p->fts_symfd);
 			if (sp->fts_child) {
@@ -316,8 +320,8 @@ fts_read(sp)
 		}
 
 		/* Rebuild if only read the names and now traversing. */
-		if (sp->fts_child && sp->fts_options & FTS_NAMEONLY) {
-			sp->fts_options &= ~FTS_NAMEONLY;
+		if (sp->fts_child && ISSET(FTS_NAMEONLY)) {
+			CLR(FTS_NAMEONLY);
 			fts_lfree(sp->fts_child);
 			sp->fts_child = NULL;
 		}
@@ -335,7 +339,7 @@ fts_read(sp)
 		 * FTS_STOP or the fts_info field of the node.
 		 */
 		if (sp->fts_child) {
-			if (CHDIR(sp, p->fts_accpath)) {
+			if (fts_safe_changedir(sp, p, -1)) {
 				p->fts_errno = errno;
 				p->fts_flags |= FTS_DONTCHDIR;
 				for (p = sp->fts_child; p; p = p->fts_link)
@@ -354,7 +358,7 @@ fts_read(sp)
 
 	/* Move to the next node on this level. */
 next:	tmp = p;
-	if ( (p = p->fts_link) ) {
+	if ((p = p->fts_link)) {
 		free(tmp);
 
 		/*
@@ -362,7 +366,7 @@ next:	tmp = p;
 		 * load the paths for the next root.
 		 */
 		if (p->fts_level == FTS_ROOTLEVEL) {
-			if (!ISSET(FTS_NOCHDIR) && FCHDIR(sp, sp->fts_rfd)) {
+			if (FCHDIR(sp, sp->fts_rfd)) {
 				SET(FTS_STOP);
 				return (NULL);
 			}
@@ -418,7 +422,7 @@ name:		t = sp->fts_path + NAPPEND(p->fts_parent);
 	 * one directory.
 	 */
 	if (p->fts_level == FTS_ROOTLEVEL) {
-		if (!ISSET(FTS_NOCHDIR) && FCHDIR(sp, sp->fts_rfd)) {
+		if (FCHDIR(sp, sp->fts_rfd)) {
 			SET(FTS_STOP);
 			return (NULL);
 		}
@@ -506,7 +510,7 @@ fts_children(sp, instr)
 		fts_lfree(sp->fts_child);
 
 	if (instr == FTS_NAMEONLY) {
-		sp->fts_options |= FTS_NAMEONLY;
+		SET(FTS_NAMEONLY);
 		instr = BNAMES;
 	} else
 		instr = BCHILD;
@@ -616,12 +620,14 @@ fts_build(sp, type)
 	 */
 	cderrno = 0;
 	if (nlinks || type == BREAD)
-		if (FCHDIR(sp, dirfd(dirp))) {
+		if (fts_safe_changedir(sp, cur, dirfd(dirp))) {
 			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
@@ -648,7 +654,7 @@ fts_build(sp, type)
 
 	/* Read the directory, attaching each entry to the `link' pointer. */
 	adjaddr = NULL;
-	for (head = tail = NULL, nitems = 0; (dp = readdir(dirp)); ) {
+	for (head = tail = NULL, nitems = 0; dirp && (dp = readdir(dirp));) {
 		if (!ISSET(FTS_SEEDOT) && ISDOT(dp->d_name))
 			continue;
 
@@ -726,7 +732,8 @@ mem1:				saved_errno = errno;
 		}
 		++nitems;
 	}
-	(void)closedir(dirp);
+	if (dirp)
+		(void)closedir(dirp);
 
 	/*
 	 * If had to realloc the path, adjust the addresses for the rest
@@ -933,7 +940,7 @@ fts_lfree(head)
 	register FTSENT *p;
 
 	/* Free a linked list of structures. */
-	while ( (p = head) ) {
+	while ((p = head)) {
 		head = head->fts_link;
 		free(p);
 	}
@@ -993,3 +1000,40 @@ fts_maxarglen(argv)
 			max = len;
 	return (max);
 }
+
+/*
+ * 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
+fts_safe_changedir(sp, p, fd)
+	FTS *sp;
+	FTSENT *p;
+	int fd;
+{
+	int ret, oerrno, newfd;
+	struct stat sb;
+
+	newfd = fd;
+	if (ISSET(FTS_NOCHDIR))
+		return (0);
+	if (fd < 0 && (newfd = open(p->fts_accpath, 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) {
+		errno = ENOENT;		/* disinformation */
+		ret = -1;
+		goto bail;
+	}
+	ret = fchdir(newfd);
+bail:
+	oerrno = errno;
+	if (fd < 0)
+		(void)close(newfd);
+	errno = oerrno;
+	return (ret);
+}