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/*-*- 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/dce.h"
#include "libc/nt/enum/fsctl.h"
#include "libc/nt/files.h"
#include "libc/nt/struct/filezerodatainformation.h"
#include "libc/sysv/consts/falloc.h"
#include "libc/sysv/errfuns.h"
/**
* Manipulates underlying physical medium of file.
*
* This system call generalizes to many powerful use cases on Linux,
* such as creating gigantic sparse files that take up little space.
* This API can polyfill a certain subset of parameters safely, e.g.
* ones identical to ftruncate(), but errs on the side of caution.
*
* @param fd must be open for writing
* @param mode can be 0, FALLOC_xxx
* @param length is how much physical space to reserve / commit
* @return 0 on success, or -1 w/ errno
* @see ftruncate()
* @syscall
*/
int fallocate(int fd, int32_t mode, int64_t offset, int64_t length) {
int rc;
uint32_t br;
if (mode == -1 /* our sysvconsts definition */) return eopnotsupp();
if (!mode && !length) return ftruncate(fd, offset);
if (IsLinux()) {
rc = fallocate$sysv(fd, mode, offset, length);
if (rc == 0x011d) rc = enosys(); /*RHEL5:CVE-2010-3301*/
return rc;
} else if (!IsWindows()) {
return posix_fallocate$sysv(fd, offset, length);
} else if (IsWindows()) {
if (!__isfdkind(fd, kFdFile)) return ebadf();
if (mode == FALLOC_FL_ZERO_RANGE) {
if (DeviceIoControl(
g_fds.p[fd].handle, kNtFsctlSetZeroData,
&(struct NtFileZeroDataInformation){offset, offset + length},
sizeof(struct NtFileZeroDataInformation), NULL, 0, &br, NULL)) {
return 0;
} else {
return __winerr();
}
} else if (!mode && !offset) {
/*
* this should commit physical space
* but not guaranteed zero'd like linux
*/
return ftruncate$nt(fd, length);
} else {
return eopnotsupp();
}
} else {
return enosys();
}
}