Jim Meyering wrote:
> if you see ways to improve things without impacting performance
> or maintainability, I'm all for it.
Maintainability wouldn't be impacted, because the fix would be to use
lib/rename.c, with
#define RENAME_DEST_EXISTS_BUG 1
#define RENAME_HARD_LINK_BUG 1
But performance would be impacted, since 2 lstat() calls would happen
before every rename().
The bug may not have a big impact, since coreutils 'mv' handles a move of a
directory to a directory differently anyway, and few other programs use
rename() on directories.
So, assuming Eric also agrees with approach (a), here's a proposal for
fixing the testsuite:
2010-11-13 Bruno Haible <br...@clisp.org>
rename, renameat: Avoid test failures at NFS mounted locations.
* tests/test-rename.h (dentry_exists, assert_nonexistent): New
functions.
(test_rename): Use assert_nonexistent.
* tests/test-rename.c: Include <dirent.h>.
* tests/test-renameat.c: Likewise.
Reported by Gary V. Vaughan <g...@gnu.org>.
--- tests/test-rename.h.orig Sat Nov 13 14:35:50 2010
+++ tests/test-rename.h Sat Nov 13 14:35:23 2010
@@ -20,6 +20,49 @@
appropriate headers are already included. If PRINT, warn before
skipping symlink tests with status 77. */
+/* Tests whether a file, given by a file name without slashes, exists in
+ the current directory, by scanning the directory entries. */
+static bool
+dentry_exists (const char *filename)
+{
+ bool exists = false;
+ DIR *dir = opendir (".");
+
+ ASSERT (dir != NULL);
+ for (;;)
+ {
+ struct dirent *d = readdir (dir);
+ if (d == NULL)
+ break;
+ if (strcmp (d->d_name, filename) == 0)
+ {
+ exists = true;
+ break;
+ }
+ }
+ ASSERT (closedir (dir) == 0);
+ return exists;
+}
+
+/* Asserts that a specific file, given by a file name without slashes, does
+ not exist in the current directory. */
+static void
+assert_nonexistent (const char *filename)
+{
+ struct stat st;
+
+ /* The usual way to test the presence of a file is via stat() or lstat(). */
+ errno = 0;
+ if (stat (filename, &st) == -1)
+ ASSERT (errno == ENOENT);
+ else
+ /* But after renaming a directory over an empty directory on an NFS-mounted
+ file system, on Linux 2.6.18, for a period of 30 seconds the old
+ directory name is "present" according to stat() but "nonexistent"
+ according to dentry_exists(). */
+ ASSERT (!dentry_exists (filename));
+}
+
static int
test_rename (int (*func) (char const *, char const *), bool print)
{
@@ -226,9 +269,7 @@
}
{ /* Full onto empty. */
ASSERT (func (BASE "dir", BASE "dir2") == 0);
- errno = 0;
- ASSERT (stat (BASE "dir", &st) == -1);
- ASSERT (errno == ENOENT);
+ assert_nonexistent (BASE "dir");
ASSERT (stat (BASE "dir2/file", &st) == 0);
/* Files present here:
{BASE}file
@@ -263,9 +304,7 @@
*/
{
ASSERT (func (BASE "dir", BASE "dir2/") == 0);
- errno = 0;
- ASSERT (stat (BASE "dir", &st) == -1);
- ASSERT (errno == ENOENT);
+ assert_nonexistent (BASE "dir");
ASSERT (stat (BASE "dir2/file", &st) == 0);
}
/* Files present here:
--- tests/test-rename.c.orig Sat Nov 13 14:35:50 2010
+++ tests/test-rename.c Sat Nov 13 14:15:34 2010
@@ -21,6 +21,7 @@
#include "signature.h"
SIGNATURE_CHECK (rename, int, (char const *, char const *));
+#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
--- tests/test-renameat.c.orig Sat Nov 13 14:35:50 2010
+++ tests/test-renameat.c Sat Nov 13 14:15:30 2010
@@ -23,6 +23,7 @@
#include "signature.h"
SIGNATURE_CHECK (renameat, int, (int, char const *, int, char const *));
+#include <dirent.h>
#include <fcntl.h>
#include <errno.h>
#include <stdbool.h>
