mirror of
https://github.com/jart/cosmopolitan.git
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85 lines
3.5 KiB
C
85 lines
3.5 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│ vi: set et 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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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/calls/calls.h"
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#include "libc/calls/internal.h"
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#include "libc/calls/syscall_support-nt.internal.h"
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#include "libc/nt/enum/filetype.h"
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#include "libc/nt/files.h"
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#include "libc/nt/struct/byhandlefileinformation.h"
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#include "libc/stdckdint.h"
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#include "libc/sysv/errfuns.h"
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#include "libc/thread/thread.h"
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static textwindows int64_t GetPosition(struct Fd *f, int whence) {
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switch (whence) {
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case SEEK_SET:
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return 0;
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case SEEK_CUR:
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return f->pointer;
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case SEEK_END: {
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struct NtByHandleFileInformation wst;
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if (!GetFileInformationByHandle(f->handle, &wst)) {
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return __winerr();
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}
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return (wst.nFileSizeHigh + 0ull) << 32 | wst.nFileSizeLow;
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}
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default:
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return einval();
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}
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}
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static textwindows int64_t Seek(struct Fd *f, int64_t offset, int whence) {
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int64_t pos;
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if ((pos = GetPosition(f, whence)) != -1) {
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if (!ckd_add(&pos, pos, offset)) {
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if (pos >= 0) {
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return pos;
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} else {
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return einval();
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}
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} else {
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return eoverflow();
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}
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} else {
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return -1;
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}
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}
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textwindows int64_t sys_lseek_nt(int fd, int64_t offset, int whence) {
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if (__isfdkind(fd, kFdDevNull) || __isfdkind(fd, kFdDevRandom)) {
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return offset;
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} else if (__isfdkind(fd, kFdFile)) {
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struct Fd *f = g_fds.p + fd;
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int filetype = GetFileType(f->handle);
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if (filetype != kNtFileTypePipe && filetype != kNtFileTypeChar) {
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int64_t res;
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if ((res = Seek(f, offset, whence)) != -1) {
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f->pointer = res;
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}
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return res;
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} else {
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return espipe();
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}
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} else if (__isfdkind(fd, kFdSocket)) {
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return espipe();
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} else {
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return ebadf();
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}
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}
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