mirror of
https://github.com/jart/cosmopolitan.git
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dc0ea6640e
This change makes further effort towards improving our poll() implementation on the New Technology. The stdin worker didn't work out so well for Python so it's not being used for now. System call tracing with the --strace flag should now be less noisy now on Windows unless you modify the strace.internal.h defines to turn on some optional ones that are most useful for debugging the system call wrappers.
132 lines
5 KiB
C
132 lines
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 net 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/bits/bits.h"
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#include "libc/calls/calls.h"
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#include "libc/calls/internal.h"
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#include "libc/calls/strace.internal.h"
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#include "libc/dce.h"
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#include "libc/errno.h"
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#include "libc/nexgen32e/kcpuids.h"
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#include "libc/nexgen32e/rdtsc.h"
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#include "libc/nexgen32e/vendor.internal.h"
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#include "libc/nexgen32e/x86feature.h"
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#include "libc/nexgen32e/x86info.h"
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#include "libc/nt/runtime.h"
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#include "libc/rand/rand.h"
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#include "libc/rand/xorshift.h"
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#include "libc/runtime/runtime.h"
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#include "libc/str/str.h"
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#include "libc/sysv/consts/at.h"
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#include "libc/sysv/consts/auxv.h"
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#include "libc/sysv/consts/grnd.h"
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#include "libc/sysv/consts/o.h"
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#include "libc/sysv/errfuns.h"
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static bool have_getrandom;
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/**
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* Returns cryptographic random data.
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*
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* This random number seed generator obtains information from:
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*
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* - getrandom() on Linux
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* - RtlGenRandom() on Windows
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* - getentropy() on XNU and OpenBSD
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* - sysctl(KERN_ARND) on FreeBSD and NetBSD
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*
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* The following flags may be specified:
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*
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* - GRND_RANDOM: Halt the entire system while I tap an entropy pool
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* so small that it's hard to use statistics to test if it's random
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* - GRND_NONBLOCK: Do not wait for i/o events or me to jiggle my
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* mouse, and instead return immediately the moment data isn't
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* available, even if the result needs to be -1 w/ EAGAIN
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*
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* This function is safe to use with fork() and vfork(). It will also
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* close any file descriptor it ends up needing before it returns.
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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 900 cycles
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* @asyncsignalsafe
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* @restartable
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* @vforksafe
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*/
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ssize_t getrandom(void *p, size_t n, unsigned f) {
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char cf;
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ssize_t rc;
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uint64_t x;
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int fd, cmd[2];
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size_t i, j, m;
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const char *via;
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sigset_t neu, old;
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if (n > 256) n = 256;
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if ((f & ~(GRND_RANDOM | GRND_NONBLOCK))) return einval();
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if (IsWindows()) {
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via = "RtlGenRandom";
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if (RtlGenRandom(p, n)) {
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rc = n;
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} else {
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rc = __winerr();
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}
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} else if (IsFreebsd() || IsNetbsd()) {
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via = "KERN_ARND";
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if (IsFreebsd()) {
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cmd[0] = 1; /* CTL_KERN */
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cmd[1] = 37; /* KERN_ARND */
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} else {
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cmd[0] = 1; /* CTL_KERN */
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cmd[1] = 81; /* KERN_ARND */
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}
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m = n;
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if ((rc = sysctl(cmd, 2, p, &m, 0, 0)) != -1) {
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rc = m;
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}
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} else if (have_getrandom) {
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via = "getrandom";
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if ((rc = sys_getrandom(p, n, f & (GRND_RANDOM | GRND_NONBLOCK))) != -1) {
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if (!rc && (IsXnu() || IsOpenbsd())) {
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rc = n;
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}
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}
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} else if ((fd = __sys_openat(
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AT_FDCWD,
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(via = (f & GRND_RANDOM) ? "/dev/random" : "/dev/urandom"),
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O_RDONLY | ((f & GRND_NONBLOCK) ? O_NONBLOCK : 0), 0)) !=
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-1) {
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rc = sys_read(fd, p, n);
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sys_close(fd);
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} else {
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rc = enosys();
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}
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STRACE("getrandom(%p, %'zu, %#x) via %s → %'ld% m", p, n, f, via, rc);
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return rc;
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}
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static textstartup void getrandom_init(void) {
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int e, rc;
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e = errno;
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if (!(rc = sys_getrandom(0, 0, 0))) {
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have_getrandom = true;
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}
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KERNTRACE("sys_getrandom(0,0,0) → %d% m");
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errno = e;
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}
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const void *const g_getrandom_init[] initarray = {getrandom_init};
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