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e16a7d8f3b
`et` means `expandtab`. ```sh rg 'vi: .* :vi' -l -0 | \ xargs -0 sed -i '' 's/vi: \(.*\) et\(.*\) :vi/vi: \1 xoet\2:vi/' rg 'vi: .* :vi' -l -0 | \ xargs -0 sed -i '' 's/vi: \(.*\)noet\(.*\):vi/vi: \1et\2 :vi/' rg 'vi: .* :vi' -l -0 | \ xargs -0 sed -i '' 's/vi: \(.*\)xoet\(.*\):vi/vi: \1noet\2:vi/' ```
94 lines
3.3 KiB
C
94 lines
3.3 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2023 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/intrin/asmflag.h"
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#include "libc/nexgen32e/x86feature.h"
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#include "libc/sysv/consts/grnd.h"
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#include "libc/sysv/errfuns.h"
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#ifdef __x86_64__
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static bool GetRandomRdseed(uint64_t *out) {
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int i;
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char cf;
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uint64_t x;
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for (i = 0; i < 10; ++i) {
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asm volatile(CFLAG_ASM("rdseed\t%1")
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: CFLAG_CONSTRAINT(cf), "=r"(x)
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: /* no inputs */
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: "cc");
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if (cf) {
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*out = x;
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return true;
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}
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asm volatile("pause");
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}
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return false;
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}
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static bool GetRandomRdrand(uint64_t *out) {
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int i;
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char cf;
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uint64_t x;
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for (i = 0; i < 10; ++i) {
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asm volatile(CFLAG_ASM("rdrand\t%1")
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: CFLAG_CONSTRAINT(cf), "=r"(x)
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: /* no inputs */
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: "cc");
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if (cf) {
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*out = x;
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return true;
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}
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asm volatile("pause");
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}
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return false;
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}
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static ssize_t GetRandomCpu(char *p, size_t n, int f, bool impl(uint64_t *)) {
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uint64_t x;
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size_t i, j;
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for (i = 0; i < n; i += j) {
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TryAgain:
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if (!impl(&x)) {
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if (f || i >= 256) break;
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goto TryAgain;
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}
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for (j = 0; j < 8 && i + j < n; ++j) {
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p[i + j] = x;
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x >>= 8;
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}
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}
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return n;
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}
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ssize_t sys_getrandom_metal(char *p, size_t n, int f) {
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if (f & GRND_RANDOM) {
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if (X86_HAVE(RDSEED)) {
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return GetRandomCpu(p, n, f, GetRandomRdseed);
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} else {
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return enosys();
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}
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} else {
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if (X86_HAVE(RDRND)) {
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return GetRandomCpu(p, n, f, GetRandomRdrand);
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} else {
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return enosys();
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}
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}
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}
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#endif /* __x86_64__ */
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