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
|
#include "config.h"
#include <assert.h>
#include <errno.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "logerr.h"
#include "random.h"
/// A temporary buffer is used to avoid writing to `addr` while having an error
/// when calling `fclose(3)`;
int
urandom_bytes(const size_t n, uint8_t (*const addr)[]) {
int rc = -1;
uint8_t *temp = NULL;
FILE *f = NULL;
temp = malloc(n);
if (temp == NULL) {
logerr("malloc(...): %s\n", strerror(errno));
goto out;
}
f = fopen("/dev/urandom", "r");
if (f == NULL) {
logerr("fopen(...): %s\n", strerror(errno));
goto out;
}
const size_t read_count = fread(temp, 1, n, f);
if (ferror(f)) {
logerr("fread(...), n, f): %s\n", strerror(errno));
goto out;
}
assert(read_count == n);
if (fclose(f)) {
logerr("fclose(...): %s\n", strerror(errno));
goto out;
}
f = NULL;
memcpy(addr, temp, n);
rc = 0;
out:
if (f != NULL) {
if (fclose(f)) {
logerr("fclose(...): %s\n", strerror(errno));
rc = -1;
}
}
if (temp != NULL) {
free(temp);
}
return rc;
}
|
