#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <sys/stat.h>
int main(int argc, char *argv[]) {
    if (argc != 2) {
        fprintf(stderr, "Usage: %s <path>\n", argv[0]);
        return 1;
    }
    const char *path = argv[1];
    
    if (faccessat(AT_FDCWD, path, F_OK, AT_SYMLINK_NOFOLLOW) == 0) {
        printf("[faccessat][without AT_EACCESS]\tFile exists: %s\n", path);
    } else {
        perror("[faccessat][without AT_EACCESS]");
    }
    
    if (faccessat(AT_FDCWD, path, F_OK, AT_SYMLINK_NOFOLLOW|AT_EACCESS) == 0) {
        printf("[faccessat][with AT_EACCESS]\tFile exists: %s\n", path);
    } else {
        perror("[faccessat][with AT_EACCESS]");
    }
    return 0;
}

sudo mkdir -p /foo/a
sudo chmod -R 700 /foo/
sudo chown -R root:root /foo/
sudo setcap "cap_dac_override=eip" faccessat_test
./faccessat_test /foo/a