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# serial 18
# Determine whether we need the chown wrapper.
dnl Copyright (C) 1997-2001, 2003-2005, 2007, 2009
dnl Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
# chown should accept arguments of -1 for uid and gid, and it should
# dereference symlinks. If it doesn't, arrange to use the replacement
# function.
# From Jim Meyering.
AC_DEFUN([gl_FUNC_CHOWN],
[
AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
AC_REQUIRE([AC_TYPE_UID_T])
AC_REQUIRE([AC_FUNC_CHOWN])
AC_REQUIRE([gl_FUNC_CHOWN_FOLLOWS_SYMLINK])
if test $ac_cv_func_chown_works = no; then
AC_DEFINE([CHOWN_FAILS_TO_HONOR_ID_OF_NEGATIVE_ONE], [1],
[Define if chown is not POSIX compliant regarding IDs of -1.])
fi
# If chown has either of the above problems, then we need the wrapper.
if test $ac_cv_func_chown_works$gl_cv_func_chown_follows_symlink = yesyes; then
: # no wrapper needed
else
REPLACE_CHOWN=1
AC_LIBOBJ([chown])
gl_PREREQ_CHOWN
fi
])
# Determine whether chown follows symlinks (it should).
AC_DEFUN([gl_FUNC_CHOWN_FOLLOWS_SYMLINK],
[
AC_CACHE_CHECK(
[whether chown(2) dereferences symlinks],
gl_cv_func_chown_follows_symlink,
[
AC_RUN_IFELSE([AC_LANG_SOURCE([[
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
int
main ()
{
char const *dangling_symlink = "conftest.dangle";
unlink (dangling_symlink);
if (symlink ("conftest.no-such", dangling_symlink))
abort ();
/* Exit successfully on a conforming system,
i.e., where chown must fail with ENOENT. */
exit ( ! (chown (dangling_symlink, getuid (), getgid ()) != 0
&& errno == ENOENT));
}
]])],
[gl_cv_func_chown_follows_symlink=yes],
[gl_cv_func_chown_follows_symlink=no],
[gl_cv_func_chown_follows_symlink=yes]
)
]
)
if test $gl_cv_func_chown_follows_symlink = no; then
AC_DEFINE([CHOWN_MODIFIES_SYMLINK], [1],
[Define if chown modifies symlinks.])
fi
])
# Prerequisites of lib/chown.c.
AC_DEFUN([gl_PREREQ_CHOWN],
[
AC_CHECK_FUNC([fchown], , [AC_LIBOBJ([fchown-stub])])
])
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