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random-util: allow RDRAND to be used in 32-bit x86 binaries

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Rename rdrand64 to rdrand, and switch from uint64_t to unsigned long.
This produces code that will compile/assemble on both x86-64 and x86-32.

This could be useful when running a 32-bit copy of systemd on a modern
Intel processor.

RDRAND is inherently arch-specific, so relying on the compiler-defined
'long' type seems reasonable.
This commit is contained in:
Mike Gilbert 2018-11-08 09:47:16 -05:00 committed by Lennart Poettering
parent e29a9fcb29
commit 33dbab6fde
3 changed files with 13 additions and 13 deletions
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14
src/basic/random-util.c
View File

@ -1,6 +1,6 @@
/* SPDX-License-Identifier: LGPL-2.1+ */
#ifdef __x86_64__
#if defined(__i386__) || defined(__x86_64__)
#include <cpuid.h>
#endif
@ -34,9 +34,9 @@
#include <sanitizer/msan_interface.h>
#endif
int rdrand64(uint64_t *ret) {
int rdrand(unsigned long *ret) {
#ifdef __x86_64__
#if defined(__i386__) || defined(__x86_64__)
static int have_rdrand = -1;
unsigned char err;
@ -95,10 +95,10 @@ int genuine_random_bytes(void *p, size_t n, RandomFlags flags) {
* allows us too, since this way we won't drain the kernel randomness pool if we don't need it, as the
* pool's entropy is scarce. */
for (;;) {
uint64_t u;
unsigned long u;
size_t m;
if (rdrand64(&u) < 0) {
if (rdrand(&u) < 0) {
if (got_some && FLAGS_SET(flags, RANDOM_EXTEND_WITH_PSEUDO)) {
/* Fill in the remaining bytes using pseudo-random values */
pseudo_random_bytes(p, n);
@ -198,7 +198,7 @@ void initialize_srand(void) {
#if HAVE_SYS_AUXV_H
const void *auxv;
#endif
uint64_t k;
unsigned long k;
if (srand_called)
return;
@ -219,7 +219,7 @@ void initialize_srand(void) {
x ^= (unsigned) now(CLOCK_REALTIME);
x ^= (unsigned) gettid();
if (rdrand64(&k) >= 0)
if (rdrand(&k) >= 0)
x ^= (unsigned) k;
srand(x);

2
src/basic/random-util.h
View File

@ -30,4 +30,4 @@ static inline uint32_t random_u32(void) {
return u;
}
int rdrand64(uint64_t *ret);
int rdrand(unsigned long *ret);

10
src/test/test-random-util.c
View File

@ -35,19 +35,19 @@ static void test_pseudo_random_bytes(void) {
}
}
static void test_rdrand64(void) {
static void test_rdrand(void) {
int r, i;
for (i = 0; i < 10; i++) {
uint64_t x = 0;
unsigned long x = 0;
r = rdrand64(&x);
r = rdrand(&x);
if (r < 0) {
log_error_errno(r, "RDRAND failed: %m");
return;
}
printf("%" PRIx64 "\n", x);
printf("%lx\n", x);
}
}
@ -61,7 +61,7 @@ int main(int argc, char **argv) {
test_pseudo_random_bytes();
test_rdrand64();
test_rdrand();
return 0;
}