nftw(): POSIX says directories causing loops should be silently skipped.

Formerly, loops caused nftw() to abort the traversal with ELOOP.

lib/libc/gen/nftw.c

@@ -65,6 +65,8 @@ nftw(const char *path, int (*fn)(const char *, const struct stat *, int,
 				continue;
 			fnflag = FTW_D;
 			break;
+		case FTS_DC:
+			continue;
 		case FTS_DNR:
 			fnflag = FTW_DNR;
 			break;
@@ -87,9 +89,6 @@ nftw(const char *path, int (*fn)(const char *, const struct stat *, int,
 		case FTS_SLNONE:
 			fnflag = FTW_SLN;
 			break;
-		case FTS_DC:
-			errno = ELOOP;
-			/* FALLTHROUGH */
 		default:
 			error = -1;
 			goto done;

tools/regression/lib/libc/gen/Makefile

@@ -1,7 +1,7 @@
 # $FreeBSD$
 
 TESTS=	test-arc4random test-fmtcheck test-fmtmsg test-fnmatch \
-	test-fpclassify test-posix_spawn test-wordexp
+	test-fpclassify test-ftw test-posix_spawn test-wordexp
 
 .PHONY: tests
 tests: ${TESTS}

tools/regression/lib/libc/gen/test-ftw.c

@@ -0,0 +1,141 @@
+/*-
+ * Copyright (c) 2012 Jilles Tjoelker
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
+ */
+
+/*
+ * Limited test program for nftw() as specified by IEEE Std. 1003.1-2008.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/wait.h>
+
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <ftw.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <spawn.h>
+
+extern char **environ;
+
+static char dir[] = "/tmp/testftw.XXXXXXXXXX";
+static int failures;
+static int ftwflags;
+
+static void
+cleanup(int ustatus __unused)
+{
+	int error, status;
+	pid_t pid, waitres;
+	const char *myargs[5];
+
+	err_set_exit(NULL);
+	myargs[0] = "rm";
+	myargs[1] = "-rf";
+	myargs[2] = "--";
+	myargs[3] = dir;
+	myargs[4] = NULL;
+	error = posix_spawnp(&pid, myargs[0], NULL, NULL,
+	    __DECONST(char **, myargs), environ);
+	if (error != 0)
+		warn("posix_spawnp rm");
+	else {
+		waitres = waitpid(pid, &status, 0);
+		if (waitres != pid)
+			warnx("waitpid rm failed");
+		else if (status != 0)
+			warnx("rm failed");
+	}
+}
+
+static int
+cb(const char *path, const struct stat *st, int type, struct FTW *f)
+{
+
+	switch (type) {
+	case FTW_D:
+		if ((ftwflags & FTW_DEPTH) == 0)
+			return (0);
+		break;
+	case FTW_DP:
+		if ((ftwflags & FTW_DEPTH) != 0)
+			return (0);
+		break;
+	case FTW_SL:
+		if ((ftwflags & FTW_PHYS) != 0)
+			return (0);
+		break;
+	}
+	warnx("unexpected path=%s type=%d f.level=%d\n",
+	    path, type, f->level);
+	failures++;
+	return (0);
+}
+
+int
+main(int argc, char *argv[])
+{
+	int fd;
+
+	if (!mkdtemp(dir))
+		err(2, "mkdtemp");
+
+	err_set_exit(cleanup);
+
+	fd = open(dir, O_DIRECTORY | O_RDONLY);
+	if (fd == -1)
+		err(2, "open %s", dir);
+
+	if (mkdirat(fd, "d1", 0777) == -1)
+		err(2, "mkdirat d1");
+
+	if (symlinkat(dir, fd, "d1/looper") == -1)
+		err(2, "symlinkat looper");
+
+	ftwflags = FTW_PHYS;
+	if (nftw(dir, cb, 10, ftwflags) == -1)
+		err(2, "nftw FTW_PHYS");
+	ftwflags = FTW_PHYS | FTW_DEPTH;
+	if (nftw(dir, cb, 10, ftwflags) == -1)
+		err(2, "nftw FTW_PHYS | FTW_DEPTH");
+	ftwflags = 0;
+	if (nftw(dir, cb, 10, ftwflags) == -1)
+		err(2, "nftw 0");
+	ftwflags = FTW_DEPTH;
+	if (nftw(dir, cb, 10, ftwflags) == -1)
+		err(2, "nftw FTW_DEPTH");
+
+	close(fd);
+
+	printf("PASS nftw()\n");
+
+	cleanup(failures != 0);
+
+	return (failures != 0);
+}