cosmopolitan/libc/calls/getrandom-metal.c
Justine Tunney c9fecf3a55
Make improvements
- You can now run `make -j8 toolchain` on Windows
- You can now run `make -j` on MacOS ARM64 and BSD OSes
- You can now use our Emacs dev environment on MacOS/Windows
- Fix bug where the x16 register was being corrupted by --ftrace
- The programs under build/bootstrap/ are updated as fat binaries
- The Makefile now explains how to download cosmocc-0.0.12 toolchain
- The build scripts under bin/ now support "cosmo" branded toolchains
- stat() now goes faster on Windows (shaves 100ms off `make` latency)
- Code cleanup and added review on the Windows signal checking code
- posix_spawnattr_setrlimit() now works around MacOS ARM64 bugs
- Landlock Make now favors posix_spawn() on non-Linux/OpenBSD
- posix_spawn() now has better --strace logging on Windows
- fstatat() can now avoid EACCES in more cases on Windows
- fchmod() can now change the readonly bit on Windows
2023-10-15 16:45:00 -07:00

94 lines
3.3 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2023 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/intrin/asmflag.h"
#include "libc/nexgen32e/x86feature.h"
#include "libc/sysv/consts/grnd.h"
#include "libc/sysv/errfuns.h"
#ifdef __x86_64__
static bool GetRandomRdseed(uint64_t *out) {
int i;
char cf;
uint64_t x;
for (i = 0; i < 10; ++i) {
asm volatile(CFLAG_ASM("rdseed\t%1")
: CFLAG_CONSTRAINT(cf), "=r"(x)
: /* no inputs */
: "cc");
if (cf) {
*out = x;
return true;
}
asm volatile("pause");
}
return false;
}
static bool GetRandomRdrand(uint64_t *out) {
int i;
char cf;
uint64_t x;
for (i = 0; i < 10; ++i) {
asm volatile(CFLAG_ASM("rdrand\t%1")
: CFLAG_CONSTRAINT(cf), "=r"(x)
: /* no inputs */
: "cc");
if (cf) {
*out = x;
return true;
}
asm volatile("pause");
}
return false;
}
static ssize_t GetRandomCpu(char *p, size_t n, int f, bool impl(uint64_t *)) {
uint64_t x;
size_t i, j;
for (i = 0; i < n; i += j) {
TryAgain:
if (!impl(&x)) {
if (f || i >= 256) break;
goto TryAgain;
}
for (j = 0; j < 8 && i + j < n; ++j) {
p[i + j] = x;
x >>= 8;
}
}
return n;
}
ssize_t sys_getrandom_metal(char *p, size_t n, int f) {
if (f & GRND_RANDOM) {
if (X86_HAVE(RDSEED)) {
return GetRandomCpu(p, n, f, GetRandomRdseed);
} else {
return enosys();
}
} else {
if (X86_HAVE(RDRND)) {
return GetRandomCpu(p, n, f, GetRandomRdrand);
} else {
return enosys();
}
}
}
#endif /* __x86_64__ */