1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
|
// version 20230126
// public domain
// djb
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <poll.h>
#include "devurandom_wrapper.h"
static void wait_for_random(void)
{
int random_fd;
struct pollfd p;
if (access("/var/run/urandom-ready",F_OK) == 0)
return;
for (;;) {
errno = 0;
random_fd = open("/dev/random",O_RDONLY);
if (random_fd >= 0) break;
if (errno == ENOENT) return;
sleep(1);
}
for (;;) {
p.fd = random_fd;
p.events = POLLIN;
p.revents = 0;
errno = 0;
if (poll(&p,1,0) == 1) break;
if (errno != EINTR) sleep(1); // e.g., ENOMEM
}
close(random_fd);
}
static int urandom_fd = -1;
int devurandom_wrapper_ready(void)
{
wait_for_random();
for (;;) {
errno = 0;
urandom_fd = open("/dev/urandom",O_RDONLY);
if (urandom_fd >= 0) break;
if (errno == ENOENT) return 0;
sleep(1);
}
fcntl(urandom_fd,F_SETFD,1);
// O_CLOEXEC is better but limits portability and is not necessary here:
// librandombytes runs *_ready only in static constructors
return 1;
}
void devurandom_wrapper(void *x,long long xbytes)
{
while (xbytes > 0) {
int todo = 1048576;
if (xbytes < 1048576) todo = xbytes;
todo = read(urandom_fd,x,todo);
if (todo < 1) {
sleep(1);
continue;
}
x += todo;
xbytes -= todo;
}
}
|
