2 # Determine whether we need the chown wrapper.
4 dnl Copyright (C) 1997-2001, 2003-2005, 2007, 2009-2014 Free Software
7 dnl This file is free software; the Free Software Foundation
8 dnl gives unlimited permission to copy and/or distribute it,
9 dnl with or without modifications, as long as this notice is preserved.
11 # chown should accept arguments of -1 for uid and gid, and it should
12 # dereference symlinks. If it doesn't, arrange to use the replacement
17 m4_version_prereq([2.70], [] ,[
19 # This is taken from the following Autoconf patch:
20 # http://git.savannah.gnu.org/gitweb/?p=autoconf.git;a=commitdiff;h=7fbb553727ed7e0e689a17594b58559ecf3ea6e9
21 AC_DEFUN([AC_FUNC_CHOWN],
23 AC_REQUIRE([AC_TYPE_UID_T])dnl
24 AC_REQUIRE([AC_CANONICAL_HOST])dnl for cross-compiles
25 AC_CHECK_HEADERS([unistd.h])
26 AC_CACHE_CHECK([for working chown],
27 [ac_cv_func_chown_works],
34 char *f = "conftest.chown";
35 struct stat before, after;
37 if (creat (f, 0600) < 0)
39 if (stat (f, &before) < 0)
41 if (chown (f, (uid_t) -1, (gid_t) -1) == -1)
43 if (stat (f, &after) < 0)
45 return ! (before.st_uid == after.st_uid && before.st_gid == after.st_gid);
48 [ac_cv_func_chown_works=yes],
49 [ac_cv_func_chown_works=no],
50 [case "$host_os" in # ((
51 # Guess yes on glibc systems.
52 *-gnu*) ac_cv_func_chown_works=yes ;;
53 # If we don't know, assume the worst.
54 *) ac_cv_func_chown_works=no ;;
59 if test $ac_cv_func_chown_works = yes; then
60 AC_DEFINE([HAVE_CHOWN], [1],
61 [Define to 1 if your system has a working `chown' function.])
67 AC_DEFUN_ONCE([gl_FUNC_CHOWN],
69 AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
70 AC_REQUIRE([AC_TYPE_UID_T])
71 AC_REQUIRE([AC_FUNC_CHOWN])
72 AC_REQUIRE([gl_FUNC_CHOWN_FOLLOWS_SYMLINK])
73 AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
74 AC_CHECK_FUNCS_ONCE([chown fchown])
76 dnl mingw lacks chown altogether.
77 if test $ac_cv_func_chown = no; then
80 dnl Some old systems treated chown like lchown.
81 if test $gl_cv_func_chown_follows_symlink = no; then
85 dnl Some old systems tried to use uid/gid -1 literally.
86 if test $ac_cv_func_chown_works = no; then
87 AC_DEFINE([CHOWN_FAILS_TO_HONOR_ID_OF_NEGATIVE_ONE], [1],
88 [Define if chown is not POSIX compliant regarding IDs of -1.])
92 dnl Solaris 9 ignores trailing slash.
93 dnl FreeBSD 7.2 mishandles trailing slash on symlinks.
94 dnl Likewise for AIX 7.1.
95 AC_CACHE_CHECK([whether chown honors trailing slash],
96 [gl_cv_func_chown_slash_works],
97 [touch conftest.file && rm -f conftest.link
98 AC_RUN_IFELSE([AC_LANG_PROGRAM([[
102 ]], [[ if (symlink ("conftest.file", "conftest.link")) return 1;
103 if (chown ("conftest.link/", getuid (), getgid ()) == 0) return 2;
105 [gl_cv_func_chown_slash_works=yes],
106 [gl_cv_func_chown_slash_works=no],
108 # Guess yes on glibc systems.
109 *-gnu*) gl_cv_func_chown_slash_works="guessing yes" ;;
110 # If we don't know, assume the worst.
111 *) gl_cv_func_chown_slash_works="guessing no" ;;
114 rm -f conftest.link conftest.file])
115 case "$gl_cv_func_chown_slash_works" in
118 AC_DEFINE([CHOWN_TRAILING_SLASH_BUG], [1],
119 [Define to 1 if chown mishandles trailing slash.])
124 dnl OpenBSD fails to update ctime if ownership does not change.
125 AC_CACHE_CHECK([whether chown always updates ctime],
126 [gl_cv_func_chown_ctime_works],
127 [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
132 #include <sys/stat.h>
133 ]], [[ struct stat st1, st2;
134 if (close (creat ("conftest.file", 0600))) return 1;
135 if (stat ("conftest.file", &st1)) return 2;
137 if (chown ("conftest.file", st1.st_uid, st1.st_gid)) return 3;
138 if (stat ("conftest.file", &st2)) return 4;
139 if (st2.st_ctime <= st1.st_ctime) return 5;
141 [gl_cv_func_chown_ctime_works=yes],
142 [gl_cv_func_chown_ctime_works=no],
144 # Guess yes on glibc systems.
145 *-gnu*) gl_cv_func_chown_ctime_works="guessing yes" ;;
146 # If we don't know, assume the worst.
147 *) gl_cv_func_chown_ctime_works="guessing no" ;;
150 rm -f conftest.file])
151 case "$gl_cv_func_chown_ctime_works" in
154 AC_DEFINE([CHOWN_CHANGE_TIME_BUG], [1], [Define to 1 if chown fails
155 to change ctime when at least one argument was not -1.])
162 # Determine whether chown follows symlinks (it should).
163 AC_DEFUN_ONCE([gl_FUNC_CHOWN_FOLLOWS_SYMLINK],
166 [whether chown dereferences symlinks],
167 [gl_cv_func_chown_follows_symlink],
169 AC_RUN_IFELSE([AC_LANG_SOURCE([[
178 char const *dangling_symlink = "conftest.dangle";
180 unlink (dangling_symlink);
181 if (symlink ("conftest.no-such", dangling_symlink))
184 /* Exit successfully on a conforming system,
185 i.e., where chown must fail with ENOENT. */
186 if (chown (dangling_symlink, getuid (), getgid ()) == 0)
193 [gl_cv_func_chown_follows_symlink=yes],
194 [gl_cv_func_chown_follows_symlink=no],
195 [gl_cv_func_chown_follows_symlink=yes]
200 if test $gl_cv_func_chown_follows_symlink = no; then
201 AC_DEFINE([CHOWN_MODIFIES_SYMLINK], [1],
202 [Define if chown modifies symlinks.])