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1/*2 * Copyright © 2018 Alexey Dobriyan <adobriyan@gmail.com>3 *4 * Permission to use, copy, modify, and distribute this software for any5 * purpose with or without fee is hereby granted, provided that the above6 * copyright notice and this permission notice appear in all copies.7 *8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF14 * 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 25static inline ssize_t sys_read(int fd, void *buf, size_t len)26{27 return syscall(SYS_read, fd, buf, len);28}29 30int 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