1 | /* |
2 | * Copyright © 2018 Alexey Dobriyan <adobriyan@gmail.com> |
3 | * |
4 | * Permission to use, copy, modify, and distribute this software for any |
5 | * purpose with or without fee is hereby granted, provided that the above |
6 | * copyright notice and this permission notice appear in all copies. |
7 | * |
8 | * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES |
9 | * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
10 | * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR |
11 | * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
12 | * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
13 | * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF |
14 | * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
15 | */ |
16 | #include <unistd.h> |
17 | #include <sys/syscall.h> |
18 | #include <sys/types.h> |
19 | #include <sys/stat.h> |
20 | #include <fcntl.h> |
21 | #include <errno.h> |
22 | #include <string.h> |
23 | #include <stdio.h> |
24 | |
25 | static inline ssize_t sys_read(int fd, void *buf, size_t len) |
26 | { |
27 | return syscall(SYS_read, fd, buf, len); |
28 | } |
29 | |
30 | int main(void) |
31 | { |
32 | char buf1[64]; |
33 | char buf2[64]; |
34 | int fd; |
35 | ssize_t rv; |
36 | |
37 | fd = open("/proc/self/syscall" , O_RDONLY); |
38 | if (fd == -1) { |
39 | if (errno == ENOENT) |
40 | return 4; |
41 | return 1; |
42 | } |
43 | |
44 | /* Do direct system call as libc can wrap anything. */ |
45 | snprintf(buf1, sizeof(buf1), "%ld 0x%lx 0x%lx 0x%lx" , |
46 | (long)SYS_read, (long)fd, (long)buf2, (long)sizeof(buf2)); |
47 | |
48 | memset(buf2, 0, sizeof(buf2)); |
49 | rv = sys_read(fd, buf2, sizeof(buf2)); |
50 | if (rv < 0) |
51 | return 1; |
52 | if (rv < strlen(buf1)) |
53 | return 1; |
54 | if (strncmp(buf1, buf2, strlen(buf1)) != 0) |
55 | return 1; |
56 | |
57 | return 0; |
58 | } |
59 | |