Problem - Kevin Tafuro

f[c + 2] = '>';
} else
snprintf(bf, sizeof(bf), "\r%d%%", (int)(entropy * 100.0 / target));
while (write(ttyfd, bf, strlen(bf)) = = -1)
if (errno != EAGAIN) abort( );
}
static void spc_end_progress_bar(int target, int ttyfd) {
int bsz, i;
if (!(bsz = spc_get_barsize(ttyfd))) {
printf("100%%\r\n");
return;
}
printf("\r[");
for (i = 0; i < bsz; i++) putchar('=');
printf("] 100%%\r\n");
}
void spc_gather_keyboard_entropy(int l, char *output) {
int fd, n;
char lastc = 0;
double entropy = 0.0;
SHA_CTX pool;
volatile char dgst[HASH_OUT_SZ];
struct termios opts;
struct {
char c;
long long timestamp;
} data;
if (l > HASH_OUT_SZ) abort( );
if ((fd = open("/dev/tty", O_RDWR)) = = -1) abort( );
spc_raw(fd, &opts);
SHA1_Init(&pool);
do {
spc_show_progress_bar(entropy, l * 8, fd);
if ((n = read(fd, &(data.c), 1)) < 1) {
if (errno = = EAGAIN) continue;
abort( );
}
current_stamp(&(data.timestamp));
SHA1_Update(&pool, &data, sizeof(data));
if (lastc != data.c) entropy += ENTROPY_PER_SAMPLE;
lastc = data.c;
} while (entropy < (l * 8));
spc_end_progress_bar(l * 8, fd);
/* Try to reset the terminal. */
tcsetattr(fd, TCSAFLUSH, &opts);
close(fd);
SHA1_Final((unsigned char *)dgst, &pool);
spc_memcpy(output, (char *)dgst, l);
spc_memset(dgst, 0, sizeof(dgst));
}
Gathering Entropy from the Keyboard | 633
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