1# getcwd.m4 - check for working getcwd that is compatible with glibc
2
3# Copyright (C) 2001, 2003-2007, 2009-2020 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 18
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 __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 "$host_os" in
51                           # Guess yes on glibc systems.
52            *-gnu* | gnu*) gl_cv_func_getcwd_null="guessing yes";;
53                           # Guess yes on musl systems.
54            *-musl*)       gl_cv_func_getcwd_null="guessing yes";;
55                           # Guess yes on Cygwin.
56            cygwin*)       gl_cv_func_getcwd_null="guessing yes";;
57                           # If we don't know, obey --enable-cross-guesses.
58            *)             gl_cv_func_getcwd_null="$gl_cross_guess_normal";;
59          esac
60        ]])])
61])
62
63AC_DEFUN([gl_FUNC_GETCWD_SIGNATURE],
64[
65  AC_CACHE_CHECK([for getcwd with POSIX signature],
66    [gl_cv_func_getcwd_posix_signature],
67    [AC_COMPILE_IFELSE(
68      [AC_LANG_PROGRAM(
69         [[#include <unistd.h>]],
70         [[extern
71           #ifdef __cplusplus
72           "C"
73           #endif
74           char *getcwd (char *, size_t);
75         ]])
76      ],
77      [gl_cv_func_getcwd_posix_signature=yes],
78      [gl_cv_func_getcwd_posix_signature=no])
79   ])
80])
81
82dnl Guarantee that getcwd will malloc with a NULL first argument.  Assumes
83dnl that either the system getcwd is robust, or that calling code is okay
84dnl with spurious failures when run from a directory with an absolute name
85dnl larger than 4k bytes.
86dnl
87dnl Assumes that getcwd exists; if you are worried about obsolete
88dnl platforms that lacked getcwd(), then you need to use the GPL module.
89AC_DEFUN([gl_FUNC_GETCWD_LGPL],
90[
91  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
92  AC_REQUIRE([gl_FUNC_GETCWD_NULL])
93  AC_REQUIRE([gl_FUNC_GETCWD_SIGNATURE])
94
95  case $gl_cv_func_getcwd_null,$gl_cv_func_getcwd_posix_signature in
96  *yes,yes) ;;
97  *)
98    dnl Minimal replacement lib/getcwd-lgpl.c.
99    REPLACE_GETCWD=1
100    ;;
101  esac
102])
103
104dnl Check for all known getcwd bugs; useful for a program likely to be
105dnl executed from an arbitrary location.
106AC_DEFUN([gl_FUNC_GETCWD],
107[
108  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
109  AC_REQUIRE([gl_FUNC_GETCWD_NULL])
110  AC_REQUIRE([gl_FUNC_GETCWD_SIGNATURE])
111  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
112
113  gl_abort_bug=no
114  case "$host_os" in
115    mingw*)
116      gl_cv_func_getcwd_path_max=yes
117      ;;
118    *)
119      gl_FUNC_GETCWD_PATH_MAX
120      case "$gl_cv_func_getcwd_null" in
121        *yes)
122          gl_FUNC_GETCWD_ABORT_BUG([gl_abort_bug=yes])
123          ;;
124      esac
125      ;;
126  esac
127  dnl Define HAVE_MINIMALLY_WORKING_GETCWD and HAVE_PARTLY_WORKING_GETCWD
128  dnl if appropriate.
129  case "$gl_cv_func_getcwd_path_max" in
130    *"no" | *"no, it has the AIX bug") ;;
131    *)
132      AC_DEFINE([HAVE_MINIMALLY_WORKING_GETCWD], [1],
133        [Define to 1 if getcwd minimally works, that is, its result can be
134         trusted when it succeeds.])
135      ;;
136  esac
137  case "$gl_cv_func_getcwd_path_max" in
138    *"no, but it is partly working")
139      AC_DEFINE([HAVE_PARTLY_WORKING_GETCWD], [1],
140        [Define to 1 if getcwd works, except it sometimes fails when it
141         shouldn't, setting errno to ERANGE, ENAMETOOLONG, or ENOENT.])
142      ;;
143    *"yes, but with shorter paths")
144      AC_DEFINE([HAVE_GETCWD_SHORTER], [1],
145        [Define to 1 if getcwd works, but with shorter paths
146         than is generally tested with the replacement.])
147      ;;
148  esac
149
150  if { case "$gl_cv_func_getcwd_null" in *yes) false;; *) true;; esac; } \
151     || test $gl_cv_func_getcwd_posix_signature != yes \
152     || { case "$gl_cv_func_getcwd_path_max" in *yes*) false;; *) true;; esac; } \
153     || test $gl_abort_bug = yes; then
154    REPLACE_GETCWD=1
155  fi
156])
157
158# Prerequisites of lib/getcwd.c, when full replacement is in effect.
159AC_DEFUN([gl_PREREQ_GETCWD],
160[
161  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
162  AC_REQUIRE([gl_CHECK_TYPE_STRUCT_DIRENT_D_INO])
163  :
164])
165