cosmopolitan/libc/intrin/msync-nt.c

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8                               :vi │
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 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/calls/syscall-nt.internal.h"
#include "libc/intrin/maps.h"
#include "libc/nt/memory.h"
#include "libc/nt/runtime.h"
#include "libc/runtime/runtime.h"
#include "libc/stdio/sysparam.h"
#include "libc/sysv/consts/auxv.h"
#include "libc/sysv/consts/map.h"
#include "libc/sysv/errfuns.h"

textwindows int sys_msync_nt(char *addr, size_t size, int flags) {
  size = (size + __pagesize - 1) & -__pagesize;

  if ((uintptr_t)addr & (__pagesize - 1))
    return einval();
  if (__maps_reentrant())
    return edeadlk();

  int rc = 0;
  __maps_lock();
  struct Map *next, *map;
  if (!(map = __maps_floor(addr)))
    map = __maps_first();
  for (; map && map->addr <= addr + size; map = next) {
    next = __maps_next(map);
    if (!__maps_isalloc(map))
      continue;
    if (map->flags & MAP_ANONYMOUS)
      continue;
    if (MAX(addr, map->addr) >= MIN(addr + size, map->addr + map->size))
      continue;  // didn't overlap mapping

    // get true size of win32 allocation
    size_t allocsize = map->size;
    while (next && !__maps_isalloc(next) &&
           next->addr + allocsize == next->addr) {
      allocsize += next->size;
      next = __maps_next(next);
    }

    // perform the flush
    if (!FlushViewOfFile(map->addr, allocsize))
      rc = -1;
    // TODO(jart): FlushFileBuffers too on g_fds handle if MS_SYNC?
  }
  __maps_unlock();

  return rc;
}