1# serial 6
2# See if we need to provide futimens replacement.
3
4dnl Copyright (C) 2009-2014 Free Software Foundation, Inc.
5dnl This file is free software; the Free Software Foundation
6dnl gives unlimited permission to copy and/or distribute it,
7dnl with or without modifications, as long as this notice is preserved.
8
9# Written by Eric Blake.
10
11AC_DEFUN([gl_FUNC_FUTIMENS],
12[
13  AC_REQUIRE([gl_SYS_STAT_H_DEFAULTS])
14  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
15  AC_CHECK_FUNCS_ONCE([futimens])
16  if test $ac_cv_func_futimens = no; then
17    HAVE_FUTIMENS=0
18  else
19    AC_CACHE_CHECK([whether futimens works],
20      [gl_cv_func_futimens_works],
21      [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
22#include <fcntl.h>
23#include <sys/stat.h>
24#include <unistd.h>
25#include <errno.h>
26]], [[struct timespec ts[2] = { { 1, UTIME_OMIT }, { 1, UTIME_NOW } };
27      int fd = creat ("conftest.file", 0600);
28      struct stat st;
29      if (fd < 0) return 1;
30      errno = 0;
31      if (futimens (AT_FDCWD, NULL) == 0) return 2;
32      if (errno != EBADF) return 3;
33      if (futimens (fd, ts)) return 4;
34      sleep (1);
35      ts[0].tv_nsec = UTIME_NOW;
36      ts[1].tv_nsec = UTIME_OMIT;
37      if (futimens (fd, ts)) return 5;
38      if (fstat (fd, &st)) return 6;
39      if (st.st_ctime < st.st_atime) return 7;
40      ]])],
41dnl FIXME: simplify this in 2012, when file system bugs are no longer common
42         [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
43#ifdef __linux__
44/* The Linux kernel added futimens in 2.6.22, but has bugs with UTIME_OMIT
45   in several file systems as recently as 2.6.32.  Always replace futimens
46   to support older kernels.  */
47choke me
48#endif
49      ]])],
50           [gl_cv_func_futimens_works=yes],
51           [gl_cv_func_futimens_works="needs runtime check"])],
52         [gl_cv_func_futimens_works=no],
53         [gl_cv_func_futimens_works="guessing no"])
54      rm -f conftest.file])
55    if test "$gl_cv_func_futimens_works" != yes; then
56      REPLACE_FUTIMENS=1
57    fi
58  fi
59])
60