2 # Determine whether we need the chown wrapper.
4 dnl Copyright (C) 1997-2001, 2003-2005, 2007, 2009-2012 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_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
24 AC_CHECK_FUNCS_ONCE([chown fchown])
26 dnl mingw lacks chown altogether.
27 if test $ac_cv_func_chown = no; then
30 dnl Some old systems treated chown like lchown.
31 if test $gl_cv_func_chown_follows_symlink = no; then
35 dnl Some old systems tried to use uid/gid -1 literally.
36 if test $ac_cv_func_chown_works = no; then
37 AC_DEFINE([CHOWN_FAILS_TO_HONOR_ID_OF_NEGATIVE_ONE], [1],
38 [Define if chown is not POSIX compliant regarding IDs of -1.])
42 dnl Solaris 9 ignores trailing slash.
43 dnl FreeBSD 7.2 mishandles trailing slash on symlinks.
44 dnl Likewise for AIX 7.1.
45 AC_CACHE_CHECK([whether chown honors trailing slash],
46 [gl_cv_func_chown_slash_works],
47 [touch conftest.file && rm -f conftest.link
48 AC_RUN_IFELSE([AC_LANG_PROGRAM([[
52 ]], [[ if (symlink ("conftest.file", "conftest.link")) return 1;
53 if (chown ("conftest.link/", getuid (), getgid ()) == 0) return 2;
55 [gl_cv_func_chown_slash_works=yes],
56 [gl_cv_func_chown_slash_works=no],
58 # Guess yes on glibc systems.
59 *-gnu*) gl_cv_func_chown_slash_works="guessing yes" ;;
60 # If we don't know, assume the worst.
61 *) gl_cv_func_chown_slash_works="guessing no" ;;
64 rm -f conftest.link conftest.file])
65 case "$gl_cv_func_chown_slash_works" in
68 AC_DEFINE([CHOWN_TRAILING_SLASH_BUG], [1],
69 [Define to 1 if chown mishandles trailing slash.])
74 dnl OpenBSD fails to update ctime if ownership does not change.
75 AC_CACHE_CHECK([whether chown always updates ctime],
76 [gl_cv_func_chown_ctime_works],
77 [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
83 ]], [[ struct stat st1, st2;
84 if (close (creat ("conftest.file", 0600))) return 1;
85 if (stat ("conftest.file", &st1)) return 2;
87 if (chown ("conftest.file", st1.st_uid, st1.st_gid)) return 3;
88 if (stat ("conftest.file", &st2)) return 4;
89 if (st2.st_ctime <= st1.st_ctime) return 5;
91 [gl_cv_func_chown_ctime_works=yes],
92 [gl_cv_func_chown_ctime_works=no],
94 # Guess yes on glibc systems.
95 *-gnu*) gl_cv_func_chown_ctime_works="guessing yes" ;;
96 # If we don't know, assume the worst.
97 *) gl_cv_func_chown_ctime_works="guessing no" ;;
100 rm -f conftest.file])
101 case "$gl_cv_func_chown_ctime_works" in
104 AC_DEFINE([CHOWN_CHANGE_TIME_BUG], [1], [Define to 1 if chown fails
105 to change ctime when at least one argument was not -1.])
112 # Determine whether chown follows symlinks (it should).
113 AC_DEFUN_ONCE([gl_FUNC_CHOWN_FOLLOWS_SYMLINK],
116 [whether chown dereferences symlinks],
117 [gl_cv_func_chown_follows_symlink],
119 AC_RUN_IFELSE([AC_LANG_SOURCE([[
128 char const *dangling_symlink = "conftest.dangle";
130 unlink (dangling_symlink);
131 if (symlink ("conftest.no-such", dangling_symlink))
134 /* Exit successfully on a conforming system,
135 i.e., where chown must fail with ENOENT. */
136 if (chown (dangling_symlink, getuid (), getgid ()) == 0)
143 [gl_cv_func_chown_follows_symlink=yes],
144 [gl_cv_func_chown_follows_symlink=no],
145 [gl_cv_func_chown_follows_symlink=yes]
150 if test $gl_cv_func_chown_follows_symlink = no; then
151 AC_DEFINE([CHOWN_MODIFIES_SYMLINK], [1],
152 [Define if chown modifies symlinks.])