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emacs/m4/futimens.m4
Paul Eggert 5d4cf1fef8 Add ‘nofollow’ flag to set-file-times
This is a companion to the recent set-file-modes patch.
It adds support for a ‘nofollow’ flag to set-file-times (Bug#39773).
Like the set-file-modes patch, it needs work in the w32 port.
* admin/merge-gnulib (GNULIB_MODULES): Add futimens, utimensat.
Remove utimens.
* doc/lispref/files.texi (Changing Files):
* etc/NEWS: Mention the change.
* lib/gnulib.mk.in, m4/gnulib-comp.m4: Regenerate.
* lisp/files.el (copy-directory):
* lisp/gnus/gnus-cloud.el (gnus-cloud-replace-file):
* lisp/net/tramp-adb.el (tramp-adb-handle-copy-file):
* lisp/net/tramp-smb.el (tramp-smb-handle-copy-file):
* lisp/tar-mode.el (tar-copy):
* test/lisp/filenotify-tests.el (file-notify-test03-events):
* test/lisp/files-tests.el:
(files-tests-file-name-non-special-set-file-times):
* test/lisp/net/tramp-tests.el (tramp-test22-file-times):
When setting file times, avoid following symbolic links
when the file is not supposed to be a symbolic link.
* lib/futimens.c, lib/utimensat.c, m4/futimens.m4, m4/utimensat.m4:
New files, copied from Gnulib.
* lisp/gnus/gnus-cloud.el (gnus-cloud-replace-file):
When creating a file that is not supposed to exist already,
use the excl flag to check this.
* lisp/net/tramp-adb.el (tramp-adb-handle-set-file-times):
* lisp/net/tramp-sh.el (tramp-sh-handle-set-file-times):
* lisp/net/tramp-sudoedit.el (tramp-sudoedit-handle-set-file-times):
Accept an optional FLAG arg that is currently ignored,
and add a FIXME comment for it.
* lisp/net/tramp-gvfs.el (tramp-gvfs-handle-set-file-times):
* src/fileio.c (Fset_file_times):
Support an optional FLAG arg.
* src/fileio.c (Fcopy_file): Use futimens instead of set_file_times,
as it’s simpler and is a POSIX API.
* src/sysdep.c (set_file_times): Move from here ...
* src/w32.c (set_file_times): ... to here, and make it static,
since it is now used only in w32.c.  Presumably w32.c should also
add support for futimens and utimensat (the POSIX APIs, which
Emacs now uses) and it can remove fdutimens (the Gnulib API,
which Emacs no longer uses).
2020-03-07 12:15:43 -08:00

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# serial 8
# See if we need to provide futimens replacement.
dnl Copyright (C) 2009-2020 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
# Written by Eric Blake.
AC_DEFUN([gl_FUNC_FUTIMENS],
[
AC_REQUIRE([gl_SYS_STAT_H_DEFAULTS])
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
AC_CHECK_FUNCS_ONCE([futimens])
if test $ac_cv_func_futimens = no; then
HAVE_FUTIMENS=0
else
AC_CACHE_CHECK([whether futimens works],
[gl_cv_func_futimens_works],
[AC_RUN_IFELSE([AC_LANG_PROGRAM([[
#include <fcntl.h>
#include <sys/stat.h>
#include <unistd.h>
#include <errno.h>
]], [[struct timespec ts[2];
int fd = creat ("conftest.file", 0600);
struct stat st;
if (fd < 0) return 1;
ts[0].tv_sec = 1;
ts[0].tv_nsec = UTIME_OMIT;
ts[1].tv_sec = 1;
ts[1].tv_nsec = UTIME_NOW;
errno = 0;
if (futimens (AT_FDCWD, NULL) == 0) return 2;
if (errno != EBADF) return 3;
if (futimens (fd, ts)) return 4;
sleep (1);
ts[0].tv_nsec = UTIME_NOW;
ts[1].tv_nsec = UTIME_OMIT;
if (futimens (fd, ts)) return 5;
if (fstat (fd, &st)) return 6;
if (st.st_ctime < st.st_atime) return 7;
]])],
[gl_cv_func_futimens_works=yes],
[gl_cv_func_futimens_works=no],
[case "$host_os" in
# Guess no on glibc systems.
*-gnu* | gnu*) gl_cv_func_futimens_works="guessing no" ;;
# Guess no on musl systems.
*-musl*) gl_cv_func_futimens_works="guessing no" ;;
# Guess yes otherwise.
*) gl_cv_func_futimens_works="guessing yes" ;;
esac
])
rm -f conftest.file])
case "$gl_cv_func_futimens_works" in
*yes) ;;
*)
REPLACE_FUTIMENS=1
;;
esac
fi
])