cosmopolitan/libc/calls/fadvise-nt.c

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2020-06-15 14:18:57 +00:00
/*-*- 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 2020 Justine Alexandra Roberts Tunney
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA
*/
#include "libc/calls/internal.h"
#include "libc/nt/enum/fileflagandattributes.h"
#include "libc/nt/enum/filesharemode.h"
#include "libc/nt/enum/status.h"
#include "libc/nt/files.h"
#include "libc/nt/nt/file.h"
#include "libc/nt/ntdll.h"
#include "libc/nt/runtime.h"
#include "libc/nt/struct/fileaccessinformation.h"
#include "libc/nt/struct/filebasicinformation.h"
#include "libc/nt/struct/iostatusblock.h"
#include "libc/runtime/runtime.h"
#include "libc/sysv/errfuns.h"
textwindows int fadvise$nt(int fd, uint64_t offset, uint64_t len, int advice) {
int64_t h2;
NtStatus status;
uint32_t sharemode;
struct NtIoStatusBlock iostatus;
struct NtFileBasicInformation basicinfo;
struct NtFileAccessInformation accessinfo;
if (!isfdkind(fd, kFdFile)) return ebadf();
sharemode = /* xxx: no clue how to query this */
kNtFileShareRead | kNtFileShareWrite | kNtFileShareDelete;
/* TODO(jart): can we do it in one call w/ NtQueryObject? */
if (!NtError(status = NtQueryInformationFile(g_fds.p[fd].handle, &iostatus,
&basicinfo, sizeof(basicinfo),
kNtFileBasicInformation)) &&
!NtError(status = NtQueryInformationFile(g_fds.p[fd].handle, &iostatus,
&accessinfo, sizeof(accessinfo),
kNtFileAccessInformation))) {
if ((h2 = ReOpenFile(g_fds.p[fd].handle, accessinfo.AccessFlags, sharemode,
advice | basicinfo.FileAttributes)) != -1) {
if (h2 != g_fds.p[fd].handle) {
CloseHandle(g_fds.p[fd].handle);
g_fds.p[fd].handle = h2;
}
return 0;
}
return winerr();
} else if (status == kNtStatusDllNotFound) {
return enosys();
} else {
return ntreturn(status);
}
}