cosmopolitan/libc/intrin/iswsl.c
2023-05-10 04:20:48 -07:00

50 lines
2.6 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 2022 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/assert.h"
#include "libc/calls/calls.h"
#include "libc/calls/syscall-sysv.internal.h"
#include "libc/dce.h"
#include "libc/errno.h"
#include "libc/intrin/likely.h"
#include "libc/sysv/consts/map.h"
#include "libc/sysv/consts/prot.h"
#ifdef __x86_64__
#define GROWSDOWN 0x00000100
#define ANONYMOUS 0x00000020
/**
* Returns true if host platform is WSL 1.0.
*/
bool IsWsl1(void) {
static char res;
if (res) return res & 1;
if (!IsLinux()) return res = 2, false;
int e = errno;
_unassert(__sys_mmap((void *)1, 4096, PROT_READ | PROT_WRITE,
MAP_FIXED | MAP_PRIVATE | ANONYMOUS | GROWSDOWN, -1, 0,
0) == MAP_FAILED);
bool tmp = errno == ENOTSUP;
errno = e;
res = 2 | tmp;
return tmp;
}
#endif /* __x86_64__ */