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// Copyright (c) 2012-2013 The Cryptonote developers
// Distributed under the MIT/X11 software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#include <assert.h>
#include <stddef.h>
#include <string.h>
#include "hash-ops.h"
#include "initializer.h"
#include "random.h"
static void generate_system_random_bytes(size_t n, void *result);
#if defined(_WIN32)
#include <windows.h>
#include <wincrypt.h>
static void generate_system_random_bytes(size_t n, void *result) {
HCRYPTPROV prov;
#define must_succeed(x) do if (!(x)) assert(0); while (0)
must_succeed(CryptAcquireContext(&prov, NULL, NULL, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT | CRYPT_SILENT));
must_succeed(CryptGenRandom(prov, (DWORD)n, result));
must_succeed(CryptReleaseContext(prov, 0));
#undef must_succeed
}
#else
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
static void generate_system_random_bytes(size_t n, void *result) {
int fd;
if ((fd = open("/dev/urandom", O_RDONLY | O_NOCTTY | O_CLOEXEC)) < 0) {
err(EXIT_FAILURE, "open /dev/urandom");
}
for (;;) {
ssize_t res = read(fd, result, n);
if ((size_t) res == n) {
break;
}
if (res < 0) {
if (errno != EINTR) {
err(EXIT_FAILURE, "read /dev/urandom");
}
} else if (res == 0) {
errx(EXIT_FAILURE, "read /dev/urandom: end of file");
} else {
result = padd(result, (size_t) res);
n -= (size_t) res;
}
}
if (close(fd) < 0) {
err(EXIT_FAILURE, "close /dev/urandom");
}
}
#endif
static union hash_state state;
#if !defined(NDEBUG)
static volatile int curstate; /* To catch thread safety problems. */
#endif
FINALIZER(deinit_random) {
#if !defined(NDEBUG)
assert(curstate == 1);
curstate = 0;
#endif
memset(&state, 0, sizeof(union hash_state));
}
INITIALIZER(init_random) {
generate_system_random_bytes(32, &state);
REGISTER_FINALIZER(deinit_random);
#if !defined(NDEBUG)
assert(curstate == 0);
curstate = 1;
#endif
}
void generate_random_bytes(size_t n, void *result) {
#if !defined(NDEBUG)
assert(curstate == 1);
curstate = 2;
#endif
if (n == 0) {
#if !defined(NDEBUG)
assert(curstate == 2);
curstate = 1;
#endif
return;
}
for (;;) {
hash_permutation(&state);
if (n <= HASH_DATA_AREA) {
memcpy(result, &state, n);
#if !defined(NDEBUG)
assert(curstate == 2);
curstate = 1;
#endif
return;
} else {
memcpy(result, &state, HASH_DATA_AREA);
result = padd(result, HASH_DATA_AREA);
n -= HASH_DATA_AREA;
}
}
}
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