gnulib/import/m4/getcwd.m4

   1 # getcwd.m4 - check for working getcwd that is compatible with glibc
   2
   3 # Copyright (C) 2001, 2003-2007, 2009-2021 Free Software Foundation, Inc.
   4 # This file is free software; the Free Software Foundation
   5 # gives unlimited permission to copy and/or distribute it,
   6 # with or without modifications, as long as this notice is preserved.
   7
   8 # Written by Paul Eggert.
   9 # serial 19
  10
  11 AC_DEFUN([gl_FUNC_GETCWD_NULL],
  12   [
  13    AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
  14    AC_CHECK_HEADERS_ONCE([unistd.h])
  15    AC_CACHE_CHECK([whether getcwd (NULL, 0) allocates memory for result],
  16      [gl_cv_func_getcwd_null],
  17      [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
  18 #        include <stdlib.h>
  19 #        if HAVE_UNISTD_H
  20 #         include <unistd.h>
  21 #        else /* on Windows with MSVC */
  22 #         include <direct.h>
  23 #        endif
  24          ]GL_MDA_DEFINES[
  25 #        ifndef getcwd
  26          char *getcwd ();
  27 #        endif
  28 ]], [[
  29 #if defined _WIN32 && ! defined __CYGWIN__
  30 /* mingw cwd does not start with '/', but _getcwd does allocate.
  31    However, mingw fails to honor non-zero size.  */
  32 #else
  33            if (chdir ("/") != 0)
  34              return 1;
  35            else
  36              {
  37                char *f = getcwd (NULL, 0);
  38                if (! f)
  39                  return 2;
  40                if (f[0] != '/')
  41                  { free (f); return 3; }
  42                if (f[1] != '\0')
  43                  { free (f); return 4; }
  44                free (f);
  45                return 0;
  46              }
  47 #endif
  48          ]])],
  49         [gl_cv_func_getcwd_null=yes],
  50         [gl_cv_func_getcwd_null=no],
  51         [[case "$host_os" in
  52                            # Guess yes on glibc systems.
  53             *-gnu* | gnu*) gl_cv_func_getcwd_null="guessing yes";;
  54                            # Guess yes on musl systems.
  55             *-musl*)       gl_cv_func_getcwd_null="guessing yes";;
  56                            # Guess yes on Cygwin.
  57             cygwin*)       gl_cv_func_getcwd_null="guessing yes";;
  58                            # If we don't know, obey --enable-cross-guesses.
  59             *)             gl_cv_func_getcwd_null="$gl_cross_guess_normal";;
  60           esac
  61         ]])])
  62 ])
  63
  64 AC_DEFUN([gl_FUNC_GETCWD_SIGNATURE],
  65 [
  66   AC_CACHE_CHECK([for getcwd with POSIX signature],
  67     [gl_cv_func_getcwd_posix_signature],
  68     [AC_COMPILE_IFELSE(
  69       [AC_LANG_PROGRAM(
  70          [[#include <unistd.h>
  71          ]GL_MDA_DEFINES],
  72          [[extern
  73            #ifdef __cplusplus
  74            "C"
  75            #endif
  76            char *getcwd (char *, size_t);
  77          ]])
  78       ],
  79       [gl_cv_func_getcwd_posix_signature=yes],
  80       [gl_cv_func_getcwd_posix_signature=no])
  81    ])
  82 ])
  83
  84 dnl Guarantee that getcwd will malloc with a NULL first argument.  Assumes
  85 dnl that either the system getcwd is robust, or that calling code is okay
  86 dnl with spurious failures when run from a directory with an absolute name
  87 dnl larger than 4k bytes.
  88 dnl
  89 dnl Assumes that getcwd exists; if you are worried about obsolete
  90 dnl platforms that lacked getcwd(), then you need to use the GPL module.
  91 AC_DEFUN([gl_FUNC_GETCWD_LGPL],
  92 [
  93   AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
  94   AC_REQUIRE([gl_FUNC_GETCWD_NULL])
  95   AC_REQUIRE([gl_FUNC_GETCWD_SIGNATURE])
  96
  97   case $gl_cv_func_getcwd_null,$gl_cv_func_getcwd_posix_signature in
  98   *yes,yes) ;;
  99   *)
 100     dnl Minimal replacement lib/getcwd-lgpl.c.
 101     REPLACE_GETCWD=1
 102     ;;
 103   esac
 104 ])
 105
 106 dnl Check for all known getcwd bugs; useful for a program likely to be
 107 dnl executed from an arbitrary location.
 108 AC_DEFUN([gl_FUNC_GETCWD],
 109 [
 110   AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
 111   AC_REQUIRE([gl_FUNC_GETCWD_NULL])
 112   AC_REQUIRE([gl_FUNC_GETCWD_SIGNATURE])
 113   AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
 114
 115   gl_abort_bug=no
 116   case "$host_os" in
 117     mingw*)
 118       gl_cv_func_getcwd_path_max=yes
 119       ;;
 120     *)
 121       gl_FUNC_GETCWD_PATH_MAX
 122       case "$gl_cv_func_getcwd_null" in
 123         *yes)
 124           gl_FUNC_GETCWD_ABORT_BUG([gl_abort_bug=yes])
 125           ;;
 126       esac
 127       ;;
 128   esac
 129   dnl Define HAVE_MINIMALLY_WORKING_GETCWD and HAVE_PARTLY_WORKING_GETCWD
 130   dnl if appropriate.
 131   case "$gl_cv_func_getcwd_path_max" in
 132     *"no" | *"no, it has the AIX bug") ;;
 133     *)
 134       AC_DEFINE([HAVE_MINIMALLY_WORKING_GETCWD], [1],
 135         [Define to 1 if getcwd minimally works, that is, its result can be
 136          trusted when it succeeds.])
 137       ;;
 138   esac
 139   case "$gl_cv_func_getcwd_path_max" in
 140     *"no, but it is partly working")
 141       AC_DEFINE([HAVE_PARTLY_WORKING_GETCWD], [1],
 142         [Define to 1 if getcwd works, except it sometimes fails when it
 143          shouldn't, setting errno to ERANGE, ENAMETOOLONG, or ENOENT.])
 144       ;;
 145     *"yes, but with shorter paths")
 146       AC_DEFINE([HAVE_GETCWD_SHORTER], [1],
 147         [Define to 1 if getcwd works, but with shorter paths
 148          than is generally tested with the replacement.])
 149       ;;
 150   esac
 151
 152   if { case "$gl_cv_func_getcwd_null" in *yes) false;; *) true;; esac; } \
 153      || test $gl_cv_func_getcwd_posix_signature != yes \
 154      || { case "$gl_cv_func_getcwd_path_max" in *yes*) false;; *) true;; esac; } \
 155      || test $gl_abort_bug = yes; then
 156     REPLACE_GETCWD=1
 157   fi
 158 ])
 159
 160 # Prerequisites of lib/getcwd.c, when full replacement is in effect.
 161 AC_DEFUN([gl_PREREQ_GETCWD],
 162 [
 163   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
 164   AC_REQUIRE([gl_CHECK_TYPE_STRUCT_DIRENT_D_INO])
 165   :
 166 ])