1/* BZ #18877, BZ #21270, and BZ #24699 mmap offset test.
2
3 Copyright (C) 2015-2022 Free Software Foundation, Inc.
4 This file is part of the GNU C Library.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <https://www.gnu.org/licenses/>. */
19
20#include <stdint.h>
21#include <stdio.h>
22#include <stdlib.h>
23#include <string.h>
24#include <unistd.h>
25#include <errno.h>
26#include <sys/mman.h>
27#include <mmap_info.h>
28
29#include <support/check.h>
30
31static int fd;
32static long int page_shift;
33static char fname[] = "/tmp/tst-mmap-offset-XXXXXX";
34
35static void
36do_prepare (int argc, char **argv)
37{
38 fd = mkstemp64 (template: fname);
39 if (fd < 0)
40 FAIL_EXIT1 ("mkstemp failed");
41
42 if (unlink (name: fname))
43 FAIL_EXIT1 ("unlink failed");
44
45 long sz = sysconf(_SC_PAGESIZE);
46 if (sz == -1)
47 sz = 4096L;
48 page_shift = ffs (sz) - 1;
49}
50
51#define PREPARE do_prepare
52
53
54/* Check if negative offsets are handled correctly by mmap. */
55static int
56do_test_bz18877 (void)
57{
58 const int prot = PROT_READ | PROT_WRITE;
59 const int flags = MAP_SHARED;
60 const unsigned long length = 0x10000;
61 const unsigned long offset = 0xace00000;
62 const unsigned long size = offset + length;
63 void *addr;
64
65 if (ftruncate64 (fd: fd, length: size))
66 FAIL_RET ("ftruncate64 failed");
67
68 addr = mmap (NULL, len: length, prot: prot, flags: flags, fd: fd, offset: offset);
69 if (MAP_FAILED == addr)
70 FAIL_RET ("mmap failed");
71
72 /* This memcpy is likely to SIGBUS if mmap has messed up with offset. */
73 memcpy (addr, fname, sizeof (fname));
74
75 return 0;
76}
77
78/* Check if invalid offset are handled correctly by mmap. */
79static int
80do_test_large_offset (void)
81{
82 /* For architectures with sizeof (off_t) < sizeof (off64_t) mmap is
83 implemented with __SYS_mmap2 syscall and the offset is represented in
84 multiples of page size. For offset larger than
85 '1 << (page_shift + 8 * sizeof (off_t))' (that is, 1<<44 on system with
86 page size of 4096 bytes) the system call silently truncates the offset.
87 For this case glibc mmap implementation returns EINVAL. */
88 const int prot = PROT_READ | PROT_WRITE;
89 const int flags = MAP_SHARED;
90 const int64_t offset = 1ULL << (page_shift + 8 * sizeof (uint32_t));
91 const size_t length = 4096;
92
93 void *addr = mmap64 (NULL, len: length, prot: prot, flags: flags, fd: fd, offset: offset);
94 if (mmap64_maximum_offset (page_shift) < UINT64_MAX)
95 {
96 if ((addr != MAP_FAILED) && (errno != EINVAL))
97 FAIL_RET ("mmap succeed");
98 }
99 else
100 {
101 if (addr == MAP_FAILED)
102 FAIL_RET ("mmap failed");
103 }
104
105 return 0;
106}
107
108int
109do_test (void)
110{
111 int ret = 0;
112
113 ret += do_test_bz18877 ();
114 ret += do_test_large_offset ();
115
116 return ret;
117}
118
119#include <support/test-driver.c>
120

source code of glibc/posix/tst-mmap-offset.c