gnulib/import/m4/lstat.m4

   1 # serial 27
   2
   3 # Copyright (C) 1997-2001, 2003-2016 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([gl_SYS_STAT_H_DEFAULTS])
  14   dnl If lstat does not exist, the replacement <sys/stat.h> does
  15   dnl "#define lstat stat", and lstat.c is a no-op.
  16   AC_CHECK_FUNCS_ONCE([lstat])
  17   if test $ac_cv_func_lstat = yes; then
  18     AC_REQUIRE([gl_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK])
  19     case "$gl_cv_func_lstat_dereferences_slashed_symlink" in
  20       *no)
  21         REPLACE_LSTAT=1
  22         ;;
  23     esac
  24   else
  25     HAVE_LSTAT=0
  26   fi
  27 ])
  28
  29 # Prerequisites of lib/lstat.c.
  30 AC_DEFUN([gl_PREREQ_LSTAT], [:])
  31
  32 AC_DEFUN([gl_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK],
  33 [
  34   dnl We don't use AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK any more, because it
  35   dnl is no longer maintained in Autoconf and because it invokes AC_LIBOBJ.
  36   AC_CACHE_CHECK([whether lstat correctly handles trailing slash],
  37     [gl_cv_func_lstat_dereferences_slashed_symlink],
  38     [rm -f conftest.sym conftest.file
  39      echo >conftest.file
  40      AC_RUN_IFELSE(
  41        [AC_LANG_PROGRAM(
  42           [AC_INCLUDES_DEFAULT],
  43           [[struct stat sbuf;
  44             if (symlink ("conftest.file", "conftest.sym") != 0)
  45               return 1;
  46             /* Linux will dereference the symlink and fail, as required by
  47                POSIX.  That is better in the sense that it means we will not
  48                have to compile and use the lstat wrapper.  */
  49             return lstat ("conftest.sym/", &sbuf) == 0;
  50           ]])],
  51        [gl_cv_func_lstat_dereferences_slashed_symlink=yes],
  52        [gl_cv_func_lstat_dereferences_slashed_symlink=no],
  53        [case "$host_os" in
  54           *-gnu*)
  55             # Guess yes on glibc systems.
  56             gl_cv_func_lstat_dereferences_slashed_symlink="guessing yes" ;;
  57           *)
  58             # If we don't know, assume the worst.
  59             gl_cv_func_lstat_dereferences_slashed_symlink="guessing no" ;;
  60         esac
  61        ])
  62      rm -f conftest.sym conftest.file
  63     ])
  64   case "$gl_cv_func_lstat_dereferences_slashed_symlink" in
  65     *yes)
  66       AC_DEFINE_UNQUOTED([LSTAT_FOLLOWS_SLASHED_SYMLINK], [1],
  67         [Define to 1 if 'lstat' dereferences a symlink specified
  68          with a trailing slash.])
  69       ;;
  70   esac
  71 ])