mirror of
https://github.com/jart/cosmopolitan.git
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3e4fd4b0ad
This change also pays off some of the remaining technical debt with stdio, file descriptors, and memory managemnt polyfills.
76 lines
3.7 KiB
C
76 lines
3.7 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ This program is free software; you can redistribute it and/or modify │
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│ it under the terms of the GNU General Public License as published by │
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│ the Free Software Foundation; version 2 of the License. │
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│ │
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│ This program is distributed in the hope that it will be useful, but │
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│ WITHOUT ANY WARRANTY; without even the implied warranty of │
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│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
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│ General Public License for more details. │
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│ │
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│ You should have received a copy of the GNU General Public License │
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│ along with this program; if not, write to the Free Software │
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│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
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│ 02110-1301 USA │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/calls/internal.h"
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#include "libc/dce.h"
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#include "libc/nt/enum/fsctl.h"
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#include "libc/nt/files.h"
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#include "libc/nt/struct/filezerodatainformation.h"
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#include "libc/sysv/consts/falloc.h"
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#include "libc/sysv/errfuns.h"
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/**
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* Manipulates underlying physical medium of file.
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*
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* This system call generalizes to many powerful use cases on Linux,
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* such as creating gigantic sparse files that take up little space.
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* This API can polyfill a certain subset of parameters safely, e.g.
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* ones identical to ftruncate(), but errs on the side of caution.
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*
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* @param fd must be open for writing
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* @param mode can be 0, FALLOC_xxx
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* @param length is how much physical space to reserve / commit
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* @return 0 on success, or -1 w/ errno
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* @see ftruncate()
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*/
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int fallocate(int fd, int32_t mode, int64_t offset, int64_t length) {
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int rc;
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uint32_t br;
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if (mode == -1 /* our sysvconsts definition */) return eopnotsupp();
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if (!mode && !length) return ftruncate(fd, offset);
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if (IsLinux()) {
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rc = fallocate$sysv(fd, mode, offset, length);
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if (rc == 0x011d) rc = enosys(); /*RHEL5:CVE-2010-3301*/
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return rc;
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} else if (!IsWindows()) {
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return posix_fallocate$sysv(fd, offset, length);
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} else if (IsWindows()) {
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if (!__isfdkind(fd, kFdFile)) return ebadf();
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if (mode == FALLOC_FL_ZERO_RANGE) {
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if (DeviceIoControl(
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g_fds.p[fd].handle, kNtFsctlSetZeroData,
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&(struct NtFileZeroDataInformation){offset, offset + length},
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sizeof(struct NtFileZeroDataInformation), NULL, 0, &br, NULL)) {
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return 0;
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} else {
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return __winerr();
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}
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} else if (!mode && !offset) {
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/*
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* this should commit physical space
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* but not guaranteed zero'd like linux
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*/
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return ftruncate$nt(fd, length);
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} else {
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return eopnotsupp();
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}
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} else {
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return enosys();
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}
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}
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