gnulib/import/m4/lstat.m4

   1 # serial 33
   2
   3 # Copyright (C) 1997-2001, 2003-2019 Free Software Foundation, Inc.
   4 #
   5 # This file is free software; the Free Software Foundation
   6 # gives unlimited permission to copy and/or distribute it,
   7 # with or without modifications, as long as this notice is preserved.
   8
   9 dnl From Jim Meyering.
  10
  11 AC_DEFUN([gl_FUNC_LSTAT],
  12 [
  13   AC_REQUIRE([AC_CANONICAL_HOST])
  14   AC_REQUIRE([gl_SYS_STAT_H_DEFAULTS])
  15   dnl If lstat does not exist, the replacement <sys/stat.h> does
  16   dnl "#define lstat stat", and lstat.c is a no-op.
  17   AC_CHECK_FUNCS_ONCE([lstat])
  18   if test $ac_cv_func_lstat = yes; then
  19     AC_REQUIRE([gl_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK])
  20     case $host_os,$gl_cv_func_lstat_dereferences_slashed_symlink in
  21       solaris* | *no)
  22         REPLACE_LSTAT=1
  23         ;;
  24     esac
  25   else
  26     HAVE_LSTAT=0
  27   fi
  28 ])
  29
  30 # Prerequisites of lib/lstat.c.
  31 AC_DEFUN([gl_PREREQ_LSTAT], [:])
  32
  33 AC_DEFUN([gl_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK],
  34 [
  35   dnl We don't use AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK any more, because it
  36   dnl is no longer maintained in Autoconf and because it invokes AC_LIBOBJ.
  37   AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
  38   AC_CACHE_CHECK([whether lstat correctly handles trailing slash],
  39     [gl_cv_func_lstat_dereferences_slashed_symlink],
  40     [rm -f conftest.sym conftest.file
  41      echo >conftest.file
  42      AC_RUN_IFELSE(
  43        [AC_LANG_PROGRAM(
  44           [AC_INCLUDES_DEFAULT],
  45           [[struct stat sbuf;
  46             if (symlink ("conftest.file", "conftest.sym") != 0)
  47               return 1;
  48             /* Linux will dereference the symlink and fail, as required by
  49                POSIX.  That is better in the sense that it means we will not
  50                have to compile and use the lstat wrapper.  */
  51             return lstat ("conftest.sym/", &sbuf) == 0;
  52           ]])],
  53        [gl_cv_func_lstat_dereferences_slashed_symlink=yes],
  54        [gl_cv_func_lstat_dereferences_slashed_symlink=no],
  55        [case "$host_os" in
  56           linux-* | linux)
  57             # Guess yes on Linux systems.
  58             gl_cv_func_lstat_dereferences_slashed_symlink="guessing yes" ;;
  59           *-gnu* | gnu*)
  60             # Guess yes on glibc systems.
  61             gl_cv_func_lstat_dereferences_slashed_symlink="guessing yes" ;;
  62           mingw*)
  63             # Guess no on native Windows.
  64             gl_cv_func_lstat_dereferences_slashed_symlink="guessing no" ;;
  65           *)
  66             # If we don't know, obey --enable-cross-guesses.
  67             gl_cv_func_lstat_dereferences_slashed_symlink="$gl_cross_guess_normal" ;;
  68         esac
  69        ])
  70      rm -f conftest.sym conftest.file
  71     ])
  72   case "$gl_cv_func_lstat_dereferences_slashed_symlink" in
  73     *yes)
  74       AC_DEFINE_UNQUOTED([LSTAT_FOLLOWS_SLASHED_SYMLINK], [1],
  75         [Define to 1 if 'lstat' dereferences a symlink specified
  76          with a trailing slash.])
  77       ;;
  78   esac
  79 ])