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1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2012 Red Hat, Inc.
4  */
5 
6 /*\
7  * [Description]
8  *
9  * Bug in the splice code has caused the file position on the write side
10  * of the sendfile system call to be incorrectly set to the read side file
11  * position. This can result in the data being written to an incorrect offset.
12  *
13  * This is a regression test for kernel commit 2cb4b05e76478.
14  */
15 
16 #include <stdio.h>
17 #include <string.h>
18 #include <sys/sendfile.h>
19 
20 #include "tst_test.h"
21 
22 #define IN_FILE		"in_file"
23 #define OUT_FILE	"out_file"
24 
25 #define TEST_MSG_IN	"world"
26 #define TEST_MSG_OUT	"hello"
27 #define TEST_MSG_ALL	(TEST_MSG_OUT TEST_MSG_IN)
28 
29 static int in_fd;
30 static int out_fd;
31 
run(void)32 static void run(void)
33 {
34 	TEST(sendfile(out_fd, in_fd, NULL, strlen(TEST_MSG_IN)));
35 	if (TST_RET == -1)
36 		tst_brk(TBROK | TTERRNO, "sendfile() failed");
37 
38 	char buf[BUFSIZ];
39 
40 	SAFE_LSEEK(out_fd, 0, SEEK_SET);
41 	SAFE_READ(0, out_fd, buf, BUFSIZ);
42 
43 	if (!strncmp(buf, TEST_MSG_ALL, strlen(TEST_MSG_ALL))) {
44 		tst_res(TPASS, "sendfile() copies data correctly");
45 		return;
46 	}
47 
48 	tst_res(TFAIL, "sendfile() copies data incorrectly: '%s' expected: '%s%s'",
49 			buf, TEST_MSG_OUT, TEST_MSG_IN);
50 }
51 
setup(void)52 static void setup(void)
53 {
54 	in_fd = SAFE_CREAT(IN_FILE, 0700);
55 	SAFE_WRITE(SAFE_WRITE_ALL, in_fd, TEST_MSG_IN, strlen(TEST_MSG_IN));
56 	SAFE_CLOSE(in_fd);
57 	in_fd = SAFE_OPEN(IN_FILE, O_RDONLY);
58 
59 	out_fd = SAFE_OPEN(OUT_FILE, O_TRUNC | O_CREAT | O_RDWR, 0777);
60 	SAFE_WRITE(SAFE_WRITE_ALL, out_fd, TEST_MSG_OUT, strlen(TEST_MSG_OUT));
61 }
62 
cleanup(void)63 static void cleanup(void)
64 {
65 	SAFE_CLOSE(in_fd);
66 	SAFE_CLOSE(out_fd);
67 }
68 
69 static struct tst_test test = {
70 	.needs_tmpdir = 1,
71 	.setup = setup,
72 	.cleanup = cleanup,
73 	.test_all = run,
74 	.tags = (const struct tst_tag[]) {
75 		{"linux-git", "2cb4b05e76478"},
76 		{}
77 	}
78 };
79