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Fold LIBC_RAND into LIBC_STDIO/TINYMATH/INTRIN
This commit is contained in:
Justine Tunney
parent
05b8f82371
commit
8a0a2c0c36
183 changed files with 149 additions and 322 deletions
146
libc/stdio/getrandom.c
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146
libc/stdio/getrandom.c
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/*-*- 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/calls/calls.h"
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#include "libc/calls/strace.internal.h"
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#include "libc/calls/struct/sigaction.h"
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#include "libc/calls/struct/sigset.h"
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#include "libc/calls/syscall-sysv.internal.h"
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#include "libc/calls/syscall_support-nt.internal.h"
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#include "libc/dce.h"
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#include "libc/errno.h"
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#include "libc/intrin/bits.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/runtime/runtime.h"
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#include "libc/stdio/rand.h"
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#include "libc/stdio/xorshift.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/consts/sig.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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struct sigaction sa, oldsa;
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if (IsBsd()) {
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sa.sa_flags = 0;
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sa.sa_handler = SIG_IGN;
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sigemptyset(&sa.sa_mask);
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sigaction(SIGSYS, &sa, &oldsa);
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}
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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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STRACE("sys_getrandom(0,0,0) → %d% m", rc);
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if (IsBsd()) {
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sigaction(SIGSYS, &oldsa, 0);
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}
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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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