projects/linux·blob master · refs

125 lines · 2.8 KiB

1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (c) 2018 Dmitry Safonov, Arista Networks
4 *
5 * MAP_POPULATE | MAP_PRIVATE should COW VMA pages.
6 */
7
8#define _GNU_SOURCE
9#include <errno.h>
10#include <fcntl.h>
11#include <sys/mman.h>
12#include <sys/socket.h>
13#include <sys/types.h>
14#include <sys/wait.h>
15#include <stdio.h>
16#include <stdlib.h>
17#include <string.h>
18#include <unistd.h>
19#include "kselftest.h"
20
21#include "vm_util.h"
22
23#define MMAP_SZ 4096
24
25#define BUG_ON(condition, description) \
26 do { \
27 if (condition) \
28 ksft_exit_fail_msg("[FAIL]\t%s:%d\t%s:%s\n", \
29 __func__, __LINE__, (description), \
30 strerror(errno)); \
31 } while (0)
32
33#define TESTS_IN_CHILD 2
34
35static void parent_f(int sock, unsigned long *smap, int child)
36{
37 int status, ret;
38
39 ret = read(sock, &status, sizeof(int));
40 BUG_ON(ret <= 0, "read(sock)");
41
42 *smap = 0x22222BAD;
43 ret = msync(smap, MMAP_SZ, MS_SYNC);
44 BUG_ON(ret, "msync()");
45
46 ret = write(sock, &status, sizeof(int));
47 BUG_ON(ret <= 0, "write(sock)");
48
49 waitpid(child, &status, 0);
50
51 /* The ksft macros don't keep counters between processes */
52 ksft_cnt.ksft_pass = WEXITSTATUS(status);
53 ksft_cnt.ksft_fail = TESTS_IN_CHILD - WEXITSTATUS(status);
54}
55
56static int child_f(int sock, unsigned long *smap, int fd)
57{
58 int ret, buf = 0;
59
60 smap = mmap(0, MMAP_SZ, PROT_READ | PROT_WRITE,
61 MAP_PRIVATE | MAP_POPULATE, fd, 0);
62 BUG_ON(smap == MAP_FAILED, "mmap()");
63
64 BUG_ON(*smap != 0xdeadbabe, "MAP_PRIVATE | MAP_POPULATE changed file");
65
66 ret = write(sock, &buf, sizeof(int));
67 BUG_ON(ret <= 0, "write(sock)");
68
69 ret = read(sock, &buf, sizeof(int));
70 BUG_ON(ret <= 0, "read(sock)");
71
72 ksft_test_result(*smap != 0x22222BAD, "MAP_POPULATE COW private page\n");
73 ksft_test_result(*smap == 0xdeadbabe, "The mapping state\n");
74
75 /* The ksft macros don't keep counters between processes */
76 return ksft_cnt.ksft_pass;
77}
78
79int main(int argc, char **argv)
80{
81 int sock[2], child, ret;
82 FILE *ftmp;
83 unsigned long *smap;
84
85 ksft_print_header();
86 ksft_set_plan(TESTS_IN_CHILD);
87
88 ftmp = tmpfile();
89 BUG_ON(!ftmp, "tmpfile()");
90
91 ret = ftruncate(fileno(ftmp), MMAP_SZ);
92 if (ret < 0 && errno == ENOENT) {
93 skip_test_dodgy_fs("ftruncate()");
94 }
95 BUG_ON(ret, "ftruncate()");
96
97 smap = mmap(0, MMAP_SZ, PROT_READ | PROT_WRITE,
98 MAP_SHARED, fileno(ftmp), 0);
99 BUG_ON(smap == MAP_FAILED, "mmap()");
100
101 *smap = 0xdeadbabe;
102 /* Probably unnecessary, but let it be. */
103 ret = msync(smap, MMAP_SZ, MS_SYNC);
104 BUG_ON(ret, "msync()");
105
106 ret = socketpair(PF_LOCAL, SOCK_SEQPACKET, 0, sock);
107 BUG_ON(ret, "socketpair()");
108
109 child = fork();
110 BUG_ON(child == -1, "fork()");
111
112 if (child) {
113 ret = close(sock[0]);
114 BUG_ON(ret, "close()");
115
116 parent_f(sock[1], smap, child);
117
118 ksft_finished();
119 }
120
121 ret = close(sock[1]);
122 BUG_ON(ret, "close()");
123
124 return child_f(sock[0], smap, fileno(ftmp));
125}