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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 │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/calls.h"
#include "libc/stdio/stdio.h"
#include "libc/sysv/consts/f.h"
#include "libc/sysv/consts/fd.h"
#include "libc/sysv/consts/o.h"
/**
* Overwrites existing stream.
*
* This function can be used in two ways. The first is sort of a
* mutating assignment. The second behavior, if pathname is NULL, is
* just changing the mode of an already open file descriptor.
*
* @param pathname is the file to open or NULL
* @param mode is the mode string flags, see fopenflags()
* @param stream is the existing allocated stream memory, which is
* flushed and closed if already open
* @return stream object if successful, or NULL w/ errno
*/
FILE *freopen(const char *pathname, const char *mode, FILE *stream) {
int fd;
unsigned flags;
flags = fopenflags(mode);
fflush(stream);
if (pathname) {
/* open new stream, overwriting existing alloc */
if ((fd = open(pathname, flags, 0666)) != -1) {
dup3(fd, stream->fd, flags & O_CLOEXEC);
close(fd);
stream->iomode = flags;
stream->beg = 0;
stream->end = 0;
return stream;
} else {
return NULL;
}
} else {
fcntl(stream->fd, F_SETFD, !!(flags & O_CLOEXEC));
fcntl(stream->fd, F_SETFL, flags & ~O_CLOEXEC);
return stream;
}
}
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