1# getcwd.m4 - check for working getcwd that is compatible with glibc
2
3# Copyright (C) 2001, 2003-2007, 2009-2017 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 14
10
11AC_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#        ifndef getcwd
25         char *getcwd ();
26#        endif
27]], [[
28#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
29/* mingw cwd does not start with '/', but getcwd does allocate.
30   However, mingw fails to honor non-zero size.  */
31#else
32           if (chdir ("/") != 0)
33             return 1;
34           else
35             {
36               char *f = getcwd (NULL, 0);
37               if (! f)
38                 return 2;
39               if (f[0] != '/')
40                 { free (f); return 3; }
41               if (f[1] != '\0')
42                 { free (f); return 4; }
43               free (f);
44               return 0;
45             }
46#endif
47         ]])],
48        [gl_cv_func_getcwd_null=yes],
49        [gl_cv_func_getcwd_null=no],
50        [[case "$host_os" in
51                     # Guess yes on glibc systems.
52            *-gnu*)  gl_cv_func_getcwd_null="guessing yes";;
53                     # Guess yes on Cygwin.
54            cygwin*) gl_cv_func_getcwd_null="guessing yes";;
55                     # If we don't know, assume the worst.
56            *)       gl_cv_func_getcwd_null="guessing no";;
57          esac
58        ]])])
59])
60
61AC_DEFUN([gl_FUNC_GETCWD_SIGNATURE],
62[
63  AC_CACHE_CHECK([for getcwd with POSIX signature],
64    [gl_cv_func_getcwd_posix_signature],
65    [AC_COMPILE_IFELSE(
66      [AC_LANG_PROGRAM(
67         [[#include <unistd.h>]],
68         [[extern
69           #ifdef __cplusplus
70           "C"
71           #endif
72           char *getcwd (char *, size_t);
73         ]])
74      ],
75      [gl_cv_func_getcwd_posix_signature=yes],
76      [gl_cv_func_getcwd_posix_signature=no])
77   ])
78])
79
80dnl Guarantee that getcwd will malloc with a NULL first argument.  Assumes
81dnl that either the system getcwd is robust, or that calling code is okay
82dnl with spurious failures when run from a directory with an absolute name
83dnl larger than 4k bytes.
84dnl
85dnl Assumes that getcwd exists; if you are worried about obsolete
86dnl platforms that lacked getcwd(), then you need to use the GPL module.
87AC_DEFUN([gl_FUNC_GETCWD_LGPL],
88[
89  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
90  AC_REQUIRE([gl_FUNC_GETCWD_NULL])
91  AC_REQUIRE([gl_FUNC_GETCWD_SIGNATURE])
92
93  case $gl_cv_func_getcwd_null,$gl_cv_func_getcwd_posix_signature in
94  *yes,yes) ;;
95  *)
96    dnl Minimal replacement lib/getcwd-lgpl.c.
97    REPLACE_GETCWD=1
98    ;;
99  esac
100])
101
102dnl Check for all known getcwd bugs; useful for a program likely to be
103dnl executed from an arbitrary location.
104AC_DEFUN([gl_FUNC_GETCWD],
105[
106  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
107  AC_REQUIRE([gl_FUNC_GETCWD_NULL])
108  AC_REQUIRE([gl_FUNC_GETCWD_SIGNATURE])
109  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
110
111  gl_abort_bug=no
112  case "$host_os" in
113    mingw*)
114      gl_cv_func_getcwd_path_max=yes
115      ;;
116    *)
117      gl_FUNC_GETCWD_PATH_MAX
118      case "$gl_cv_func_getcwd_null" in
119        *yes)
120          gl_FUNC_GETCWD_ABORT_BUG([gl_abort_bug=yes])
121          ;;
122      esac
123      ;;
124  esac
125  dnl Define HAVE_MINIMALLY_WORKING_GETCWD and HAVE_PARTLY_WORKING_GETCWD
126  dnl if appropriate.
127  case "$gl_cv_func_getcwd_path_max" in
128    "no"|"no, it has the AIX bug") ;;
129    *)
130      AC_DEFINE([HAVE_MINIMALLY_WORKING_GETCWD], [1],
131        [Define to 1 if getcwd minimally works, that is, its result can be
132         trusted when it succeeds.])
133      ;;
134  esac
135  case "$gl_cv_func_getcwd_path_max" in
136    "no, but it is partly working")
137      AC_DEFINE([HAVE_PARTLY_WORKING_GETCWD], [1],
138        [Define to 1 if getcwd works, except it sometimes fails when it
139         shouldn't, setting errno to ERANGE, ENAMETOOLONG, or ENOENT.])
140      ;;
141    "yes, but with shorter paths")
142      AC_DEFINE([HAVE_GETCWD_SHORTER], [1],
143        [Define to 1 if getcwd works, but with shorter paths
144         than is generally tested with the replacement.])
145      ;;
146  esac
147
148  if { case "$gl_cv_func_getcwd_null" in *yes) false;; *) true;; esac; } \
149     || test $gl_cv_func_getcwd_posix_signature != yes \
150     || { case "$gl_cv_func_getcwd_path_max" in *yes*) false;; *) true;; esac; } \
151     || test $gl_abort_bug = yes; then
152    REPLACE_GETCWD=1
153  fi
154])
155
156# Prerequisites of lib/getcwd.c, when full replacement is in effect.
157AC_DEFUN([gl_PREREQ_GETCWD],
158[
159  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
160  AC_REQUIRE([gl_CHECK_TYPE_STRUCT_DIRENT_D_INO])
161  :
162])
163