Hi Paul,
> I installed the attached patch to Gnulib in preparation for the upcoming
> glibc fix. The patch causes fchmodat with AT_SYMLINK_NOFOLLOW to work on
> non-symlinks, and similarly for lchmod on non-symlinks. The idea is to
> avoid this sort of problem in the future, and to let Coreutils etc. work
> on older platforms as if glibc 2.32 (or whatever) is already in place.
Some improvements:
1) Improve the cross-compilation guesses. The result of the
"fchmodat+AT_SYMLINK_NOFOLLOW works on non-symlinks" test is:
- yes on kFreeBSD/glibc, Hurd/glibc, FreeBSD 12, AIX 7.2, Solaris 11, Haiku,
- no on Linux/glibc, Cygwin 2.9.
2) On Cygwin, the functions fchmodat and lchown crash. The cause is an endless
recursion, because some of the #includes in fchmodat.c includes the full
<sys/stat.h>, including the '#define fchmodat rpl_fchmodat'.
3) Strengthen the unit test, and make sure that it does not write files that
other unit tests could possibly write as well.
This test is a bit tricky, because on native Windows, we cannot do arbitrary
chmods:
- chmod of 700 is equivalent to 600 (since it does not have an execute bit
on the file system),
- chmod of 600 sets the mode to 666 - since there is no distinction between
users, group, and world with this API.
- After a chmod of 400 (= read-only), unlink() fails.
2020-02-08 Bruno Haible <br...@clisp.org>
fchmodat: Strengthen tests.
* tests/test-fchmodat.c (BASE): New macro.
(main): Use it, to avoid conflicts with other unit tests. Verify that
fchmodat changed the file permission bits.
2020-02-08 Bruno Haible <br...@clisp.org>
fchmodat: Fix endless recursion on Cygwin (regression from 2020-02-07).
* lib/fchmodat.c (orig_fchmodat): Move definition to immediately after
'#undef __need_system_sys_stat_h'.
2020-02-08 Bruno Haible <br...@clisp.org>
fchmodat: Improve cross-compilation guesses.
* m4/fchmodat.m4 (gl_FUNC_FCHMODAT): Require AC_CANONICAL_HOST. When
cross-compiling, guess depending on the platform.
* doc/posix-functions/fchmodat.texi: Clarify.
>From a680228fe4d39f749cb819e45202c6fec6ca9d29 Mon Sep 17 00:00:00 2001
From: Bruno Haible <br...@clisp.org>
Date: Sat, 8 Feb 2020 20:38:01 +0100
Subject: [PATCH 1/3] fchmodat: Improve cross-compilation guesses.
* m4/fchmodat.m4 (gl_FUNC_FCHMODAT): Require AC_CANONICAL_HOST. When
cross-compiling, guess depending on the platform.
* doc/posix-functions/fchmodat.texi: Clarify.
---
ChangeLog | 7 +++++++
doc/posix-functions/fchmodat.texi | 10 +++++-----
m4/fchmodat.m4 | 14 +++++++++++---
3 files changed, 23 insertions(+), 8 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index df48e88..32d9a00 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,12 @@
2020-02-08 Bruno Haible <br...@clisp.org>
+ fchmodat: Improve cross-compilation guesses.
+ * m4/fchmodat.m4 (gl_FUNC_FCHMODAT): Require AC_CANONICAL_HOST. When
+ cross-compiling, guess depending on the platform.
+ * doc/posix-functions/fchmodat.texi: Clarify.
+
+2020-02-08 Bruno Haible <br...@clisp.org>
+
Fix compilation errors in a testdir created with --with-c++-tests.
* lib/c++defs.h (_GL_CXXALIASWARN1_2): Do not use __typeof__ (func),
since it does not work any more with g++ >= 4.4.
diff --git a/doc/posix-functions/fchmodat.texi b/doc/posix-functions/fchmodat.texi
index 4d19031..a295f83 100644
--- a/doc/posix-functions/fchmodat.texi
+++ b/doc/posix-functions/fchmodat.texi
@@ -9,15 +9,15 @@ Gnulib module: fchmodat
Portability problems fixed by Gnulib:
@itemize
@item
-When given the @code{AT_SYMLINK_NOFOLLOW} flag,
-this function fails with @code{errno} set to @code{ENOTSUP},
-even when the file is not a symbolic link:
-GNU/Linux and Cygwin with glibc 2.31.
-@item
This function is missing on some platforms:
glibc 2.3.6, Mac OS X 10.5, FreeBSD 6.0, NetBSD 5.0, OpenBSD 3.8, Minix 3.1.8,
AIX 5.1, HP-UX 11, IRIX 6.5, Solaris 10, Cygwin 1.5.x, mingw, MSVC 14.
But the replacement function is not safe to be used in libraries and is not multithread-safe.
+@item
+When given the @code{AT_SYMLINK_NOFOLLOW} flag,
+this function fails with @code{errno} set to @code{ENOTSUP},
+even when the file is not a symbolic link:
+GNU/Linux with glibc 2.31, Cygwin 2.9.
@end itemize
Portability problems not fixed by Gnulib:
diff --git a/m4/fchmodat.m4 b/m4/fchmodat.m4
index 8195ef6..f284485 100644
--- a/m4/fchmodat.m4
+++ b/m4/fchmodat.m4
@@ -1,4 +1,4 @@
-# fchmodat.m4 serial 2
+# fchmodat.m4 serial 3
dnl Copyright (C) 2004-2020 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
@@ -10,6 +10,7 @@ AC_DEFUN([gl_FUNC_FCHMODAT],
[
AC_REQUIRE([gl_SYS_STAT_H_DEFAULTS])
AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+ AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
AC_CHECK_FUNCS_ONCE([fchmodat lchmod])
if test $ac_cv_func_fchmodat != yes; then
HAVE_FCHMODAT=0
@@ -17,7 +18,9 @@ AC_DEFUN([gl_FUNC_FCHMODAT],
AC_CACHE_CHECK(
[whether fchmodat+AT_SYMLINK_NOFOLLOW works on non-symlinks],
[gl_cv_func_fchmodat_works],
- [AC_RUN_IFELSE(
+ [dnl This test fails on GNU/Linux with glibc 2.31 (but not on
+ dnl GNU/kFreeBSD nor GNU/Hurd) and Cygwin 2.9.
+ AC_RUN_IFELSE(
[AC_LANG_PROGRAM(
[
AC_INCLUDES_DEFAULT[
@@ -53,7 +56,12 @@ AC_DEFUN([gl_FUNC_FCHMODAT],
]])],
[gl_cv_func_fchmodat_works=yes],
[gl_cv_func_fchmodat_works=no],
- [gl_cv_func_fchmodat_works=$gl_cross_guess_normal])
+ [case "$host_os" in
+ dnl Guess no on Linux with glibc and Cygwin, yes otherwise.
+ linux-gnu* | cygwin*) gl_cv_func_fchmodat_works="guessing no" ;;
+ *) gl_cv_func_fchmodat_works="$gl_cross_guess_normal" ;;
+ esac
+ ])
rm -f conftest.fchmodat])
case $gl_cv_func_fchmodat_works in
*yes) ;;
--
2.7.4
>From 1bbbce29dc592833e79ab6d21472528a01ab67b2 Mon Sep 17 00:00:00 2001
From: Bruno Haible <br...@clisp.org>
Date: Sat, 8 Feb 2020 20:41:20 +0100
Subject: [PATCH 2/3] fchmodat: Fix endless recursion on Cygwin (regression
from 2020-02-07).
* lib/fchmodat.c (orig_fchmodat): Move definition to immediately after
'#undef __need_system_sys_stat_h'.
---
ChangeLog | 6 ++++++
lib/fchmodat.c | 12 ++++++------
2 files changed, 12 insertions(+), 6 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 32d9a00..a5ca210 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
2020-02-08 Bruno Haible <br...@clisp.org>
+ fchmodat: Fix endless recursion on Cygwin (regression from 2020-02-07).
+ * lib/fchmodat.c (orig_fchmodat): Move definition to immediately after
+ '#undef __need_system_sys_stat_h'.
+
+2020-02-08 Bruno Haible <br...@clisp.org>
+
fchmodat: Improve cross-compilation guesses.
* m4/fchmodat.m4 (gl_FUNC_FCHMODAT): Require AC_CANONICAL_HOST. When
cross-compiling, guess depending on the platform.
diff --git a/lib/fchmodat.c b/lib/fchmodat.c
index c6b8ef7..87aa0d1 100644
--- a/lib/fchmodat.c
+++ b/lib/fchmodat.c
@@ -26,12 +26,6 @@
#include <sys/stat.h>
#undef __need_system_sys_stat_h
-#include <errno.h>
-#include <fcntl.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
-
#if HAVE_FCHMODAT
static int
orig_fchmodat (int dir, char const *file, mode_t mode, int flags)
@@ -40,6 +34,12 @@ orig_fchmodat (int dir, char const *file, mode_t mode, int flags)
}
#endif
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
#ifdef __osf__
/* Write "sys/stat.h" here, not <sys/stat.h>, otherwise OSF/1 5.1 DTK cc
eliminates this include because of the preliminary #include <sys/stat.h>
--
2.7.4
>From c2d184186846851f173bec9e60781a05001837c6 Mon Sep 17 00:00:00 2001
From: Bruno Haible <br...@clisp.org>
Date: Sat, 8 Feb 2020 20:47:58 +0100
Subject: [PATCH 3/3] fchmodat: Strengthen tests.
* tests/test-fchmodat.c (BASE): New macro.
(main): Use it, to avoid conflicts with other unit tests. Verify that
fchmodat changed the file permission bits.
---
ChangeLog | 7 +++++++
tests/test-fchmodat.c | 14 +++++++++++---
2 files changed, 18 insertions(+), 3 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index a5ca210..fc07914 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,12 @@
2020-02-08 Bruno Haible <br...@clisp.org>
+ fchmodat: Strengthen tests.
+ * tests/test-fchmodat.c (BASE): New macro.
+ (main): Use it, to avoid conflicts with other unit tests. Verify that
+ fchmodat changed the file permission bits.
+
+2020-02-08 Bruno Haible <br...@clisp.org>
+
fchmodat: Fix endless recursion on Cygwin (regression from 2020-02-07).
* lib/fchmodat.c (orig_fchmodat): Move definition to immediately after
'#undef __need_system_sys_stat_h'.
diff --git a/tests/test-fchmodat.c b/tests/test-fchmodat.c
index df0f604..f6b695b 100644
--- a/tests/test-fchmodat.c
+++ b/tests/test-fchmodat.c
@@ -28,6 +28,8 @@ SIGNATURE_CHECK (fchmodat, int, (int, const char *, mode_t, int));
#include "macros.h"
+#define BASE "test-fchmodat."
+
int
main (void)
{
@@ -47,9 +49,15 @@ main (void)
/* Test that fchmodat works on non-symlinks, when given
the AT_SYMLINK_NOFOLLOW flag. */
{
- ASSERT (close (creat ("file", 0600)) == 0);
- ASSERT (fchmodat (AT_FDCWD, "file", 0700, AT_SYMLINK_NOFOLLOW) == 0);
- ASSERT (unlink ("file") == 0);
+ struct stat statbuf;
+ unlink (BASE "file");
+ ASSERT (close (creat (BASE "file", 0600)) == 0);
+ ASSERT (fchmodat (AT_FDCWD, BASE "file", 0400, AT_SYMLINK_NOFOLLOW) == 0);
+ ASSERT (stat (BASE "file", &statbuf) >= 0);
+ ASSERT ((statbuf.st_mode & 0700) == 0400);
+ /* Clean up. */
+ ASSERT (chmod (BASE "file", 0600) == 0);
+ ASSERT (unlink (BASE "file") == 0);
}
return 0;
--
2.7.4
