mirror of
https://github.com/jart/cosmopolitan.git
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6e6fc38935
Commit bc6c183 introduced a bunch of discrepancies between what files
look like in the repo and what clang-format says they should look like.
However, there were already a few discrepancies prior to that. Most of
these discrepancies seemed to be unintentional, but a few of them were
load-bearing (e.g., a #include that violated header ordering needing
something to have been #defined by a 'later' #include.)
I opted to take what I hope is a relatively smooth-brained approach: I
reverted the .clang-format change, ran clang-format on the whole repo,
reapplied the .clang-format change, reran clang-format again, and then
reverted the commit that contained the first run. Thus the full effect
of this PR should only be to apply the changed formatting rules to the
repo, and from skimming the results, this seems to be the case.
My work can be checked by applying the short, manual commits, and then
rerunning the command listed in the autogenerated commits (those whose
messages I have prefixed auto:) and seeing if your results agree.
It might be that the other diffs should be fixed at some point but I'm
leaving that aside for now.
fd '\.c(c|pp)?$' --print0| xargs -0 clang-format -i
83 lines
3.5 KiB
C
83 lines
3.5 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 2020 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/errno.h"
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#include "libc/intrin/asmflag.h"
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#include "libc/nexgen32e/x86feature.h"
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#include "libc/stdio/rand.h"
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#include "libc/sysv/consts/grnd.h"
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__static_yoink("rdrand_init");
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static dontinline uint64_t rdrand_failover(void) {
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int f;
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size_t i;
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ssize_t r;
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volatile uint64_t b;
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register uint64_t x;
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for (f = GRND_RANDOM | GRND_NONBLOCK, i = 0; i < 8; i += r) {
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if ((r = getrandom((char *)&b + i, 8 - i, f)) <= 0) {
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if (r == -1 && errno == EINTR) {
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r = 0;
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} else if (r == -1 && errno == EAGAIN) {
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r = 0;
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f = 0;
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} else {
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return _rand64();
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}
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}
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}
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x = b;
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b = 0;
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return x;
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}
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/**
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* Retrieves 64-bits of hardware random data from RDRAND instruction.
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*
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* If RDRAND isn't available (we check CPUID and we also disable it
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* automatically for microarchitectures where it's slow or buggy) then
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* we try getrandom(), ProcessPrng(), or sysctl(KERN_ARND). If those
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* aren't available then we try /dev/urandom and if that fails, we try
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* getauxval(AT_RANDOM), and if not we finally use RDTSC and getpid().
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*
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* @note this function could block a nontrivial time on old computers
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* @note this function is indeed intended for cryptography
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* @note this function takes around 300 cycles
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* @see rngset(), rdseed(), _rand64()
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* @asyncsignalsafe
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* @vforksafe
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*/
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uint64_t rdrand(void) {
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int i;
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char cf;
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uint64_t x;
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if (X86_HAVE(RDRND)) {
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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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return x;
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asm volatile("pause");
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}
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}
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return rdrand_failover();
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}
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