1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Author: SeongJae Park <sj@kernel.org>
4 */
5
6 #include <fcntl.h>
7 #include <stdlib.h>
8 #include <unistd.h>
9 #include <stdio.h>
10
11 #pragma GCC diagnostic push
12 #if __GNUC__ >= 11 && __GNUC_MINOR__ >= 1
13 /* Ignore read(2) overflow and write(2) overread compile warnings */
14 #pragma GCC diagnostic ignored "-Wstringop-overread"
15 #pragma GCC diagnostic ignored "-Wstringop-overflow"
16 #endif
17
18 void write_read_with_huge_count(char *file)
19 {
20 int filedesc = open(file, O_RDWR);
21 char buf[25];
22 int ret;
23
24 printf("%s %s\n", __func__, file);
25 if (filedesc < 0) {
26 fprintf(stderr, "failed opening %s\n", file);
27 exit(1);
28 }
29
30 write(filedesc, "", 0xfffffffful);
31 perror("after write: ");
32 ret = read(filedesc, buf, 0xfffffffful);
33 perror("after read: ");
34 close(filedesc);
35 }
36
37 #pragma GCC diagnostic pop
38
39 int main(int argc, char *argv[])
40 {
41 if (argc != 2) {
42 fprintf(stderr, "Usage: %s <file>\n", argv[0]);
43 exit(1);
44 }
45 write_read_with_huge_count(argv[1]);
46
47 return 0;
48 }
49
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