b.liu | e958203 | 2025-04-17 19:18:16 +0800 | [diff] [blame^] | 1 | #include <stdio.h> |
| 2 | #include <unistd.h> |
| 3 | #include <sys/types.h> |
| 4 | #include <sys/stat.h> |
| 5 | #include <fcntl.h> |
| 6 | #include <stdlib.h> |
| 7 | |
| 8 | #define BUF_SIZE 256 |
| 9 | |
| 10 | static __attribute__((noinline)) |
| 11 | void urandom_read(int fd, int count) |
| 12 | { |
| 13 | char buf[BUF_SIZE]; |
| 14 | int i; |
| 15 | |
| 16 | for (i = 0; i < count; ++i) |
| 17 | read(fd, buf, BUF_SIZE); |
| 18 | } |
| 19 | |
| 20 | int main(int argc, char *argv[]) |
| 21 | { |
| 22 | int fd = open("/dev/urandom", O_RDONLY); |
| 23 | int count = 4; |
| 24 | |
| 25 | if (fd < 0) |
| 26 | return 1; |
| 27 | |
| 28 | if (argc == 2) |
| 29 | count = atoi(argv[1]); |
| 30 | |
| 31 | urandom_read(fd, count); |
| 32 | |
| 33 | close(fd); |
| 34 | return 0; |
| 35 | } |