2 # Determine whether we need the chown wrapper.
4 dnl Copyright (C) 1997-2001, 2003-2005, 2007, 2009-2011 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 AC_DEFUN_ONCE([gl_FUNC_CHOWN],
19 AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
20 AC_REQUIRE([AC_TYPE_UID_T])
21 AC_REQUIRE([AC_FUNC_CHOWN])
22 AC_REQUIRE([gl_FUNC_CHOWN_FOLLOWS_SYMLINK])
23 AC_CHECK_FUNCS_ONCE([chown fchown])
25 dnl mingw lacks chown altogether.
26 if test $ac_cv_func_chown = no; then
29 dnl Some old systems treated chown like lchown.
30 if test $gl_cv_func_chown_follows_symlink = no; then
34 dnl Some old systems tried to use uid/gid -1 literally.
35 if test $ac_cv_func_chown_works = no; then
36 AC_DEFINE([CHOWN_FAILS_TO_HONOR_ID_OF_NEGATIVE_ONE], [1],
37 [Define if chown is not POSIX compliant regarding IDs of -1.])
41 dnl Solaris 9 ignores trailing slash.
42 dnl FreeBSD 7.2 mishandles trailing slash on symlinks.
43 dnl Likewise for AIX 7.1.
44 AC_CACHE_CHECK([whether chown honors trailing slash],
45 [gl_cv_func_chown_slash_works],
46 [touch conftest.file && rm -f conftest.link
47 AC_RUN_IFELSE([AC_LANG_PROGRAM([[
51 ]], [[ if (symlink ("conftest.file", "conftest.link")) return 1;
52 if (chown ("conftest.link/", getuid (), getgid ()) == 0) return 2;
54 [gl_cv_func_chown_slash_works=yes],
55 [gl_cv_func_chown_slash_works=no],
56 [gl_cv_func_chown_slash_works="guessing no"])
57 rm -f conftest.link conftest.file])
58 if test "$gl_cv_func_chown_slash_works" != yes; then
59 AC_DEFINE([CHOWN_TRAILING_SLASH_BUG], [1],
60 [Define to 1 if chown mishandles trailing slash.])
64 dnl OpenBSD fails to update ctime if ownership does not change.
65 AC_CACHE_CHECK([whether chown always updates ctime],
66 [gl_cv_func_chown_ctime_works],
67 [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
73 ]], [[ struct stat st1, st2;
74 if (close (creat ("conftest.file", 0600))) return 1;
75 if (stat ("conftest.file", &st1)) return 2;
77 if (chown ("conftest.file", st1.st_uid, st1.st_gid)) return 3;
78 if (stat ("conftest.file", &st2)) return 4;
79 if (st2.st_ctime <= st1.st_ctime) return 5;
81 [gl_cv_func_chown_ctime_works=yes],
82 [gl_cv_func_chown_ctime_works=no],
83 [gl_cv_func_chown_ctime_works="guessing no"])
85 if test "$gl_cv_func_chown_ctime_works" != yes; then
86 AC_DEFINE([CHOWN_CHANGE_TIME_BUG], [1], [Define to 1 if chown fails
87 to change ctime when at least one argument was not -1.])
93 # Determine whether chown follows symlinks (it should).
94 AC_DEFUN_ONCE([gl_FUNC_CHOWN_FOLLOWS_SYMLINK],
97 [whether chown dereferences symlinks],
98 [gl_cv_func_chown_follows_symlink],
100 AC_RUN_IFELSE([AC_LANG_SOURCE([[
109 char const *dangling_symlink = "conftest.dangle";
111 unlink (dangling_symlink);
112 if (symlink ("conftest.no-such", dangling_symlink))
115 /* Exit successfully on a conforming system,
116 i.e., where chown must fail with ENOENT. */
117 if (chown (dangling_symlink, getuid (), getgid ()) == 0)
124 [gl_cv_func_chown_follows_symlink=yes],
125 [gl_cv_func_chown_follows_symlink=no],
126 [gl_cv_func_chown_follows_symlink=yes]
131 if test $gl_cv_func_chown_follows_symlink = no; then
132 AC_DEFINE([CHOWN_MODIFIES_SYMLINK], [1],
133 [Define if chown modifies symlinks.])