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
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         ]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
64AC_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
84dnl Guarantee that getcwd will malloc with a NULL first argument.  Assumes
85dnl that either the system getcwd is robust, or that calling code is okay
86dnl with spurious failures when run from a directory with an absolute name
87dnl larger than 4k bytes.
88dnl
89dnl Assumes that getcwd exists; if you are worried about obsolete
90dnl platforms that lacked getcwd(), then you need to use the GPL module.
91AC_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
106dnl Check for all known getcwd bugs; useful for a program likely to be
107dnl executed from an arbitrary location.
108AC_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.
161AC_DEFUN([gl_PREREQ_GETCWD],
162[
163  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
164  AC_REQUIRE([gl_CHECK_TYPE_STRUCT_DIRENT_D_INO])
165  :
166])
167