| 1 | |
| 2 | * Copyright © 2018 Alexey Dobriyan <[email protected]>
|
| 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 |
|
| 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 | }
|