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/* $OpenBSD: findfp.c,v 1.15 2013/12/17 16:33:27 deraadt Exp $ */
/*-
* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Chris Torek.
*
* 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 University 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 REGENTS 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 REGENTS 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 <sys/param.h>
#include <unistd.h>
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include "local.h"
#include "glue.h"
#include "private/thread_private.h"
#define ALIGNBYTES (sizeof(uintptr_t) - 1)
#define ALIGN(p) (((uintptr_t)(p) + ALIGNBYTES) &~ ALIGNBYTES)
int __sdidinit;
#define NDYNAMIC 10 /* add ten more whenever necessary */
#define std(flags, file) \
{0,0,0,flags,file,{0,0},0,__sF+file,__sclose,__sread,__sseek,__swrite, \
{(unsigned char *)(__sFext+file), 0},NULL,0,{0},{0},{0,0},0,0}
/* the usual - (stdin + stdout + stderr) */
static FILE usual[FOPEN_MAX - 3];
static struct __sfileext usualext[FOPEN_MAX - 3];
static struct glue uglue = { 0, FOPEN_MAX - 3, usual };
static struct glue *lastglue = &uglue;
_THREAD_PRIVATE_MUTEX(__sfp_mutex);
static struct __sfileext __sFext[3];
FILE __sF[3] = {
std(__SRD, STDIN_FILENO), /* stdin */
std(__SWR, STDOUT_FILENO), /* stdout */
std(__SWR|__SNBF, STDERR_FILENO) /* stderr */
};
FILE* stdin = &__sF[0];
FILE* stdout = &__sF[1];
FILE* stderr = &__sF[2];
struct glue __sglue = { &uglue, 3, __sF };
static struct glue *
moreglue(int n)
{
struct glue *g;
FILE *p;
struct __sfileext *pext;
static FILE empty;
char *data;
data = malloc(sizeof(*g) + ALIGNBYTES + n * sizeof(FILE)
+ n * sizeof(struct __sfileext));
if (data == NULL)
return (NULL);
g = (struct glue *)data;
p = (FILE *)ALIGN(data + sizeof(*g));
pext = (struct __sfileext *)
(ALIGN(data + sizeof(*g)) + n * sizeof(FILE));
g->next = NULL;
g->niobs = n;
g->iobs = p;
while (--n >= 0) {
*p = empty;
_FILEEXT_SETUP(p, pext);
p++;
pext++;
}
return (g);
}
/*
* Find a free FILE for fopen et al.
*/
FILE *
__sfp(void)
{
FILE *fp;
int n;
struct glue *g;
if (!__sdidinit)
__sinit();
_THREAD_PRIVATE_MUTEX_LOCK(__sfp_mutex);
for (g = &__sglue; g != NULL; g = g->next) {
for (fp = g->iobs, n = g->niobs; --n >= 0; fp++)
if (fp->_flags == 0)
goto found;
}
/* release lock while mallocing */
_THREAD_PRIVATE_MUTEX_UNLOCK(__sfp_mutex);
if ((g = moreglue(NDYNAMIC)) == NULL)
return (NULL);
_THREAD_PRIVATE_MUTEX_LOCK(__sfp_mutex);
lastglue->next = g;
lastglue = g;
fp = g->iobs;
found:
fp->_flags = 1; /* reserve this slot; caller sets real flags */
_THREAD_PRIVATE_MUTEX_UNLOCK(__sfp_mutex);
fp->_p = NULL; /* no current pointer */
fp->_w = 0; /* nothing to read or write */
fp->_r = 0;
fp->_bf._base = NULL; /* no buffer */
fp->_bf._size = 0;
fp->_lbfsize = 0; /* not line buffered */
fp->_file = -1; /* no file */
/* fp->_cookie = <any>; */ /* caller sets cookie, _read/_write etc */
fp->_lb._base = NULL; /* no line buffer */
fp->_lb._size = 0;
_FILEEXT_INIT(fp);
return (fp);
}
/*
* exit() and abort() call _cleanup() through the callback registered
* with __atexit_register_cleanup(), set whenever we open or buffer a
* file. This chicanery is done so that programs that do not use stdio
* need not link it all in.
*
* The name `_cleanup' is, alas, fairly well known outside stdio.
*/
void
_cleanup(void)
{
/* (void) _fwalk(fclose); */
(void) _fwalk(__sflush); /* `cheating' */
}
/*
* __sinit() is called whenever stdio's internal variables must be set up.
*/
void
__sinit(void)
{
_THREAD_PRIVATE_MUTEX(__sinit_mutex);
_THREAD_PRIVATE_MUTEX_LOCK(__sinit_mutex);
if (__sdidinit) {
/* bail out if caller lost the race */
_THREAD_PRIVATE_MUTEX_UNLOCK(__sinit_mutex);
return;
}
/* Initialize stdin/stdout/stderr (for the recursive mutex). http://b/18208568. */
for (size_t i = 0; i < 3; ++i) {
_FILEEXT_SETUP(__sF+i, __sFext+i);
}
/* Initialize the pre-allocated (but initially unused) streams. */
for (size_t i = 0; i < FOPEN_MAX - 3; ++i) {
_FILEEXT_SETUP(usual+i, usualext+i);
}
/* make sure we clean up on exit */
__atexit_register_cleanup(_cleanup); /* conservative */
__sdidinit = 1;
_THREAD_PRIVATE_MUTEX_UNLOCK(__sinit_mutex);
}
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