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/*
* Copyright © 2018 Alexey Dobriyan <adobriyan@gmail.com>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#define _GNU_SOURCE
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <stdio.h>
static inline ssize_t sys_read(int fd, void *buf, size_t len)
{
return syscall(SYS_read, fd, buf, len);
}
int main(void)
{
char buf1[64];
char buf2[64];
int fd;
ssize_t rv;
fd = open("/proc/self/syscall", O_RDONLY);
if (fd == -1) {
if (errno == ENOENT)
return 4;
return 1;
}
/* Do direct system call as libc can wrap anything. */
snprintf(buf1, sizeof(buf1), "%ld 0x%lx 0x%lx 0x%lx",
(long)SYS_read, (long)fd, (long)buf2, (long)sizeof(buf2));
memset(buf2, 0, sizeof(buf2));
rv = sys_read(fd, buf2, sizeof(buf2));
if (rv < 0)
return 1;
if (rv < strlen(buf1))
return 1;
if (strncmp(buf1, buf2, strlen(buf1)) != 0)
return 1;
return 0;
}
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