/*      $NetBSD: findfp.c,v 1.28 2012/03/27 15:05:42 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 1.28 2012/03/27 15:05:42 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 = NULL, \
        ._r = 0, \
        ._w = 0, \
        ._flags = (flags), \
        ._file = (file),  \
        ._bf = { ._base = NULL, ._size = 0 }, \
        ._lbfsize = 0,  \
        ._cookie = __sF + (file), \
        ._close = __sclose, \
        ._read = __sread, \
        ._seek = __sseek, \
        ._write = __swrite, \
        ._ext = { ._base = (void *)(__sFext + (file)), ._size = 0 }, \
        ._up = NULL, \
        ._ur = 0, \
        ._ubuf = { [0] = '\0', [1] = '\0', [2] = '\0' }, \
        ._nbuf = { [0] = '\0' }, \
        ._flush = NULL, \
        ._lb_unused = { '\0' }, \
        ._blksize = 0, \
        ._offset = (off_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 };

void f_prealloc(void);

#ifdef _REENTRANT
rwlock_t __sfp_lock = RWLOCK_INITIALIZER;
#endif

static struct glue *
moreglue(int n)
{
        struct glue *g;
        FILE *p;
        struct __sfileext *pext;
        static FILE empty;

        g = 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 */
        fp->_flush = NULL;      /* default flush */
        _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(void)
{
        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(void)
{
        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)
                continue;
        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)
{
        /* (void) _fwalk(fclose); */
        (void) fflush(NULL);                    /* `cheating' */
}

/*
 * __sinit() is called whenever stdio's internal variables must be set up.
 */
void
__sinit(void)
{
        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;
}