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.
94 lines
4.1 KiB
C
94 lines
4.1 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/calls.h"
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#include "libc/calls/internal.h"
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#include "libc/dce.h"
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#include "libc/errno.h"
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#include "libc/nt/enum/accessmask.h"
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#include "libc/nt/enum/fileflagandattributes.h"
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#include "libc/nt/enum/filesharemode.h"
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#include "libc/nt/files.h"
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#include "libc/nt/runtime.h"
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#include "libc/stdio/stdio.h"
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#include "libc/sysv/consts/f.h"
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#include "libc/sysv/consts/fd.h"
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#include "libc/sysv/consts/fileno.h"
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#include "libc/sysv/consts/o.h"
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/**
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* Overwrites existing stream.
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*
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* This function can be used in two ways. The first is sort of a
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* mutating assignment. The second behavior, if pathname is NULL, is
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* just changing the mode of an already open file descriptor.
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*
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* @param pathname is the file to open or NULL
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* @param mode is the mode string flags, see fopenflags()
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* @param stream is the existing allocated stream memory, which is
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* flushed and closed if already open
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* @return stream object if successful, or NULL w/ errno
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*/
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FILE *freopen(const char *pathname, const char *mode, FILE *stream) {
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int fd;
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unsigned flags;
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flags = fopenflags(mode);
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fflush(stream);
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if (pathname) {
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/* open new stream, overwriting existing alloc */
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if ((fd = open(pathname, flags, 0666)) != -1) {
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if (!IsWindows()) {
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dup3(fd, stream->fd, (flags & O_CLOEXEC));
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close(fd);
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} else {
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g_fds.p[stream->fd].handle = g_fds.p[fd].handle;
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g_fds.p[fd].kind = kFdEmpty;
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}
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stream->iomode = flags;
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return stream;
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} else {
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return NULL;
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}
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} else {
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/* change mode of open file */
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if (!IsWindows()) {
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if (flags & O_CLOEXEC) {
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if (fcntl$sysv(stream->fd, F_SETFD, FD_CLOEXEC) == -1) return NULL;
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flags &= ~O_CLOEXEC;
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}
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if (flags) {
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if (fcntl$sysv(stream->fd, F_SETFL, flags) == -1) return NULL;
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}
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return stream;
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} else {
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if (ReOpenFile(
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stream->fd,
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(flags & O_RDWR) == O_RDWR ? kNtGenericWrite : kNtGenericRead,
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(flags & O_EXCL) == O_EXCL
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? kNtFileShareExclusive
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: kNtFileShareRead | kNtFileShareWrite | kNtFileShareDelete,
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kNtFileAttributeNormal)) {
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return stream;
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} else {
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__winerr();
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return NULL;
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}
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}
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}
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}
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