1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (c) International Business Machines  Corp., 2012
4 * Copyright (c) Linux Test Project, 2012
5 * Copyright (C) 2021 SUSE LLC Andrea Cervesato <andrea.cervesato@suse.com>
6 */
7
8/*\
9 * [Description]
10 *
11 * Fork two children, the first one allocates a chunk of memory and the
12 * other one call process_vm_writev to write known data into the first
13 * child. Then first child verifies that the data is as expected.
14 */
15
16#include <stdlib.h>
17#include <sys/types.h>
18#include <sys/uio.h>
19#include "tst_test.h"
20#include "lapi/syscalls.h"
21
22static uintptr_t *data_ptr;
23static char *str_buffsize;
24static int bufsize = 100000;
25
26static void child_alloc_and_verify(int buffsize)
27{
28	char foo[buffsize];
29	int i;
30	int err;
31
32	tst_res(TINFO, "child 0: allocate memory");
33
34	memset(foo, 'a', buffsize);
35	*data_ptr = (uintptr_t)foo;
36
37	TST_CHECKPOINT_WAKE_AND_WAIT(0);
38
39	err = 0;
40	for (i = 0; i < buffsize; i++)
41		if (foo[i] != 'w')
42			err++;
43
44	if (err)
45		tst_res(TFAIL, "child 0: found %d differences from expected data", err);
46	else
47		tst_res(TPASS, "child 0: read back expected data");
48}
49
50static void child_write(int buffsize, pid_t pid_alloc)
51{
52	char lp[buffsize];
53	struct iovec local, remote;
54
55	tst_res(TINFO, "child 1: write to the same memory location");
56
57	memset(lp, 'w', buffsize);
58
59	local.iov_base = lp;
60	local.iov_len = buffsize;
61	remote.iov_base = (void *)*data_ptr;
62	remote.iov_len = buffsize;
63
64	TST_EXP_POSITIVE(tst_syscall(__NR_process_vm_writev, pid_alloc, &local,
65				     1UL, &remote, 1UL, 0UL));
66
67	if (TST_RET != buffsize) {
68		tst_brk(TBROK, "process_vm_writev: expected %d bytes but got %ld",
69			buffsize, TST_RET);
70	}
71}
72
73static void setup(void)
74{
75	tst_syscall(__NR_process_vm_writev, getpid(), NULL, 0UL, NULL, 0UL, 0UL);
76
77	if (tst_parse_int(str_buffsize, &bufsize, 1, INT_MAX))
78		tst_brk(TBROK, "Invalid buffer size '%s'", str_buffsize);
79
80	data_ptr = SAFE_MMAP(NULL, sizeof(uintptr_t), PROT_READ | PROT_WRITE,
81			     MAP_SHARED | MAP_ANONYMOUS, -1, 0);
82}
83
84static void cleanup(void)
85{
86	if (data_ptr)
87		SAFE_MUNMAP(data_ptr, sizeof(uintptr_t));
88}
89
90static void run(void)
91{
92	pid_t pid_alloc;
93	pid_t pid_write;
94	int status;
95
96	pid_alloc = SAFE_FORK();
97	if (!pid_alloc) {
98		child_alloc_and_verify(bufsize);
99		return;
100	}
101
102	TST_CHECKPOINT_WAIT(0);
103
104	pid_write = SAFE_FORK();
105	if (!pid_write) {
106		child_write(bufsize, pid_alloc);
107		return;
108	}
109
110	SAFE_WAITPID(pid_write, &status, 0);
111	if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
112		tst_res(TFAIL, "write child: %s", tst_strstatus(status));
113
114	TST_CHECKPOINT_WAKE(0);
115}
116
117static struct tst_test test = {
118	.test_all = run,
119	.setup = setup,
120	.cleanup = cleanup,
121	.forks_child = 1,
122	.needs_checkpoints = 1,
123	.options =
124		(struct tst_option[]){
125			{ "s:", &str_buffsize, "Total buffer size (default 100000)" },
126			{},
127		},
128};
129