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/*
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright © 2019 Keith Packard
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* 3. Neither the name of the copyright holder nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "stdio_private.h"
#ifdef __STDIO_BUFIO_LOCKING
void
__bufio_lock_init(FILE *f)
{
struct __file_bufio *bf = (struct __file_bufio *)f;
__LIBC_LOCK();
if (!bf->lock)
__lock_init(bf->lock);
__LIBC_UNLOCK();
}
#endif
int
__bufio_flush_locked(FILE *f)
{
struct __file_bufio *bf = (struct __file_bufio *)f;
char *buf;
off_t backup;
switch (bf->dir) {
case __SWR:
/* Flush everything, drop contents if that doesn't work */
buf = bf->buf;
while (bf->len) {
ssize_t this = bufio_write(bf, buf, bf->len);
if (this <= 0) {
bf->len = 0;
return _FDEV_ERR;
break;
}
buf += this;
bf->pos += this;
bf->len -= this;
}
break;
case __SRD:
/* Move the FD back to the current read position */
backup = bf->len - bf->off;
if (backup) {
bf->pos -= backup;
(void)bufio_lseek(bf, bf->pos, SEEK_SET);
}
bf->len = 0;
bf->off = 0;
break;
default:
break;
}
return 0;
}
int
__bufio_fill_locked(FILE *f)
{
struct __file_bufio *bf = (struct __file_bufio *)f;
ssize_t len;
/* Reset read pointer, read some data */
bf->off = 0;
len = bufio_read(bf, bf->buf, bf->size);
if (len <= 0) {
bf->len = 0;
if (len < 0)
return _FDEV_ERR;
else
return _FDEV_EOF;
}
/* Update FD pos */
bf->len = len;
bf->pos += len;
return 0;
}
int
__bufio_flush(FILE *f)
{
int ret;
__bufio_lock(f);
ret = __bufio_flush_locked(f);
__bufio_unlock(f);
return ret;
}
/* Set I/O direction, flushing when it changes */
int
__bufio_setdir_locked(FILE *f, uint8_t dir)
{
struct __file_bufio *bf = (struct __file_bufio *)f;
int ret = 0;
if (bf->dir != dir) {
ret = __bufio_flush_locked(f);
bf->dir = dir;
}
return ret;
}
int
__bufio_put(char c, FILE *f)
{
struct __file_bufio *bf = (struct __file_bufio *)f;
int ret = (unsigned char)c;
__bufio_lock(f);
if (__bufio_setdir_locked(f, __SWR) < 0) {
ret = _FDEV_ERR;
goto bail;
}
bf->buf[bf->len++] = c;
/* flush if full, or if sending newline when linebuffered */
if (bf->len >= bf->size || (c == '\n' && (bf->bflags & __BLBF)))
if (__bufio_flush_locked(f) < 0)
ret = _FDEV_ERR;
bail:
__bufio_unlock(f);
return ret;
}
extern FILE * const stdin __weak;
extern FILE * const stdout __weak;
int
__bufio_get(FILE *f)
{
struct __file_bufio *bf = (struct __file_bufio *)f;
int ret;
bool flushed = false;
again:
__bufio_lock(f);
if (__bufio_setdir_locked(f, __SRD) < 0) {
ret = _FDEV_ERR;
goto bail;
}
if (bf->off >= bf->len) {
/*
* Flush stdout if reading from stdin.
*
* The odd-looking NULL address checks along with the
* weak attributes for stdin and stdout above avoids
* pulling in stdin/stdout definitions just for this
* check.
*/
if (!flushed) {
flushed = true;
if (&stdin != NULL && &stdout != NULL && f == stdin) {
__bufio_unlock(f);
fflush(stdout);
goto again;
}
}
ret = __bufio_fill_locked(f);
if (ret)
goto bail;
}
/*
* Cast to unsigned avoids sign-extending chars with high-bit
* set
*/
ret = (unsigned char)bf->buf[bf->off++];
bail:
__bufio_unlock(f);
return ret;
}
off_t
__bufio_seek(FILE *f, off_t offset, int whence)
{
struct __file_bufio *bf = (struct __file_bufio *)f;
off_t ret;
__bufio_lock(f);
if (__bufio_setdir_locked(f, __SRD) < 0) {
ret = _FDEV_ERR;
} else {
/* compute offset of the first char in the buffer */
__off_t buf_pos = bf->pos - bf->len;
switch (whence) {
case SEEK_CUR:
/* Map CUR -> SET, accounting for position within buffer */
whence = SEEK_SET;
offset += buf_pos + bf->off;
__fallthrough;
case SEEK_SET:
/* Optimize for seeks within buffer or just past buffer */
if (buf_pos <= offset && offset <= buf_pos + bf->len) {
bf->off = offset - buf_pos;
ret = offset;
break;
}
__fallthrough;
default:
ret = bufio_lseek(bf, offset, whence);
if (ret >= 0)
bf->pos = ret;
/* Flush any buffered data after a real seek */
bf->len = 0;
bf->off = 0;
break;
}
}
__bufio_unlock(f);
return ret;
}