1 // SPDX-License-Identifier: GPL-2.0-or-later
2
3 /*
4 * Copyright (c) International Business Machines Corp., 2003
5 * Author: by Paul Larson
6 * Copyright (C) 2024 SUSE LLC Andrea Manzini <[email protected]>
7 */
8
9 /*\
10 * [Description]
11 *
12 * Verify that truncating a mmaped file works correctly.
13 *
14 * Use ftruncate to:
15 *
16 * 1. shrink the file while it is mapped
17 * 2. grow the file while it is mapped
18 * 3. zero the size of the file while it is mapped
19 */
20
21 #include "tst_test.h"
22
23 /* size of the test file = 64 KB */
24 #define MAPSIZE (64 * 1024)
25
26 static int fd;
27 static char *maddr;
28
29 static struct test_case
30 {
31 off_t newsize;
32 char *desc;
33 } tcases[] = {
34 {MAPSIZE - 8192, "ftruncate mmaped file to a smaller size"},
35 {MAPSIZE + 1024, "ftruncate mmaped file to a larger size"},
36 {0, "ftruncate mmaped file to 0 size"},
37 };
38
verify_mmap(unsigned int nr)39 static void verify_mmap(unsigned int nr)
40 {
41 struct test_case *tc = &tcases[nr];
42
43 TST_EXP_PASS(ftruncate(fd, tc->newsize), "%s", tc->desc);
44 }
45
setup(void)46 static void setup(void)
47 {
48 fd = SAFE_OPEN("/tmp/mmaptest", O_RDWR | O_CREAT, 0666);
49
50 /* set the file to initial size */
51 SAFE_FTRUNCATE(fd, MAPSIZE);
52 maddr = SAFE_MMAP(0, MAPSIZE, PROT_READ | PROT_WRITE, MAP_FILE | MAP_SHARED, fd, 0);
53
54 /* fill up the file with A's */
55 memset(maddr, 'A', MAPSIZE);
56 }
57
cleanup(void)58 static void cleanup(void)
59 {
60 if (maddr)
61 SAFE_MUNMAP(maddr, MAPSIZE);
62
63 if (fd)
64 SAFE_CLOSE(fd);
65 }
66
67 static struct tst_test test = {
68 .setup = setup,
69 .cleanup = cleanup,
70 .test = verify_mmap,
71 .tcnt = ARRAY_SIZE(tcases),
72 .needs_tmpdir = 1,
73 };
74