minix/lib/libc/stdio/findfp.c

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/* $NetBSD: findfp.c,v 1.25 2010/09/06 14:52:55 christos 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/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char sccsid[] = "@(#)findfp.c 8.2 (Berkeley) 1/4/94";
#else
__RCSID("$NetBSD: findfp.c,v 1.25 2010/09/06 14:52:55 christos Exp $");
#endif
#endif /* LIBC_SCCS and not lint */
#include "namespace.h"
#include <sys/param.h>
#include <unistd.h>
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include "reentrant.h"
#include "local.h"
#include "glue.h"
int __sdidinit;
#define NDYNAMIC 10 /* add ten more whenever necessary */
#define std(flags, file) \
/* p r w flags file bf lfbsize cookie close */ \
{ NULL, 0, 0, flags, file, { NULL, 0 }, 0, __sF + file, __sclose, \
/* read seek write ext up */ \
__sread, __sseek, __swrite, { (void *)(__sFext + file), 0 }, NULL, \
/* ur ubuf, nbuf lb blksize offset */ \
0, { '\0', '\0', '\0' }, { '\0' }, { NULL, 0 }, 0, (fpos_t)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 };
#if defined(_REENTRANT) && !defined(__lint__) /* XXX lint is busted */
#define STDEXT { ._lock = MUTEX_INITIALIZER, ._lockcond = COND_INITIALIZER }
struct __sfileext __sFext[3] = { STDEXT,
STDEXT,
STDEXT};
#else
struct __sfileext __sFext[3];
#endif
FILE __sF[3] = {
std(__SRD, STDIN_FILENO), /* stdin */
std(__SWR, STDOUT_FILENO), /* stdout */
std(__SWR|__SNBF, STDERR_FILENO) /* stderr */
};
struct glue __sglue = { &uglue, 3, __sF };
static struct glue *moreglue __P((int));
void f_prealloc __P((void));
#ifdef _REENTRANT
rwlock_t __sfp_lock = RWLOCK_INITIALIZER;
#endif
static struct glue *
moreglue(n)
int n;
{
struct glue *g;
FILE *p;
struct __sfileext *pext;
static FILE empty;
g = (struct glue *)malloc(sizeof(*g) + ALIGNBYTES + n * sizeof(FILE)
+ n * sizeof(struct __sfileext));
if (g == NULL)
return (NULL);
p = (FILE *)ALIGN((u_long)(g + 1));
g->next = NULL;
g->niobs = n;
g->iobs = p;
pext = (void *)(p + n);
while (--n >= 0) {
*p = empty;
_FILEEXT_SETUP(p, pext);
p++;
pext++;
}
return (g);
}
void
__sfpinit(FILE *fp)
{
fp->_flags = 1; /* reserve this slot; caller sets real flags */
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 */
_UB(fp)._base = NULL; /* no ungetc buffer */
_UB(fp)._size = 0;
memset(WCIO_GET(fp), 0, sizeof(struct wchar_io_data));
}
/*
* Find a free FILE for fopen et al.
*/
FILE *
__sfp()
{
FILE *fp;
int n;
struct glue *g;
if (!__sdidinit)
__sinit();
rwlock_wrlock(&__sfp_lock);
for (g = &__sglue;; g = g->next) {
for (fp = g->iobs, n = g->niobs; --n >= 0; fp++)
if (fp->_flags == 0)
goto found;
if (g->next == NULL && (g->next = moreglue(NDYNAMIC)) == NULL)
break;
}
rwlock_unlock(&__sfp_lock);
return (NULL);
found:
__sfpinit(fp);
rwlock_unlock(&__sfp_lock);
return (fp);
}
/*
* XXX. Force immediate allocation of internal memory. Not used by stdio,
* but documented historically for certain applications. Bad applications.
*/
void
f_prealloc()
{
struct glue *g;
int n;
n = (int)sysconf(_SC_OPEN_MAX) - FOPEN_MAX + 20; /* 20 for slop. */
for (g = &__sglue; (n -= g->niobs) > 0 && g->next; g = g->next)
/* void */;
if (n > 0)
g->next = moreglue(n);
}
/*
* exit() calls _cleanup() through *__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) _fwalk(fclose); */
(void) fflush(NULL); /* `cheating' */
}
/*
* __sinit() is called whenever stdio's internal variables must be set up.
*/
void
__sinit()
{
int i;
for (i = 0; i < FOPEN_MAX - 3; i++)
_FILEEXT_SETUP(&usual[i], &usualext[i]);
/* make sure we clean up on exit */
__cleanup = _cleanup; /* conservative */
__sdidinit = 1;
}