1#!/bin/sh
2# Running cp S D on an NFS client while another client has just removed D
3# would lead (w/coreutils-8.16 and earlier) to cp's initial stat call
4# seeing (via stale NFS cache) that D exists, so that cp would then call
5# open without the O_CREAT flag.  Yet, the open must actually consult
6# the server, which confesses that D has been deleted, thus causing the
7# open call to fail with ENOENT.
8#
9# This test simulates that situation by intercepting stat for a nonexistent
10# destination, D, and making the stat fill in the result struct for another
11# file and return 0.
12#
13# This test is skipped on systems that lack LD_PRELOAD support; that's fine.
14# Similarly, on a system that lacks <dlfcn.h> or __xstat, skipping it is fine.
15
16# Copyright (C) 2012-2023 Free Software Foundation, Inc.
17
18# This program is free software: you can redistribute it and/or modify
19# it under the terms of the GNU General Public License as published by
20# the Free Software Foundation, either version 3 of the License, or
21# (at your option) any later version.
22
23# This program is distributed in the hope that it will be useful,
24# but WITHOUT ANY WARRANTY; without even the implied warranty of
25# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
26# GNU General Public License for more details.
27
28# You should have received a copy of the GNU General Public License
29# along with this program.  If not, see <https://www.gnu.org/licenses/>.
30
31. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
32print_ver_ cp
33require_gcc_shared_
34
35# Replace each stat call with a call to this wrapper.
36cat > k.c <<'EOF' || framework_failure_
37#define _GNU_SOURCE
38#include <stdio.h>
39#include <sys/types.h>
40#include <dlfcn.h>
41
42#define __xstat __xstat_orig
43
44#include <sys/stat.h>
45#include <stddef.h>
46
47#undef __xstat
48
49int
50__xstat (int ver, const char *path, struct stat *st)
51{
52  static int (*real_stat)(int ver, const char *path, struct stat *st) = NULL;
53  fclose(fopen("preloaded", "w"));
54  if (!real_stat)
55    real_stat = dlsym (RTLD_NEXT, "__xstat");
56  /* When asked to stat nonexistent "d",
57     return results suggesting it exists. */
58  return real_stat (ver, *path == 'd' && path[1] == 0 ? "d2" : path, st);
59}
60EOF
61
62# Then compile/link it:
63gcc_shared_ k.c k.so \
64  || framework_failure_ 'failed to build shared library'
65
66touch d2 || framework_failure_
67echo xyz > src || framework_failure_
68
69# Finally, run the test:
70LD_PRELOAD=$LD_PRELOAD:./k.so cp src d || fail=1
71
72test -f preloaded || skip_ 'LD_PRELOAD was ineffective?'
73
74compare src d || fail=1
75Exit $fail
76