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scoutos / prex-0.9.0 / usr / lib / libc / stdio / findfp.c @ 03e9c04a

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/*-
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 * Copyright (c) 1990, 1993
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 *        The Regents of the University of California.  All rights reserved.
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 *
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 * This code is derived from software contributed to Berkeley by
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 * Chris Torek.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 * 1. Redistributions of source code must retain the above copyright
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 *    notice, this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    notice, this list of conditions and the following disclaimer in the
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 *    documentation and/or other materials provided with the distribution.
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 * 3. Neither the name of the University nor the names of its contributors
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 *    may be used to endorse or promote products derived from this software
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 *    without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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 * SUCH DAMAGE.
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 */
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#include <sys/param.h>
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#include <unistd.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <errno.h>
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#include <string.h>
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#include "local.h"
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int        __sdidinit;
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FILE __sF[3];
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static void
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std(FILE *fp, FILE *next, short flags, short fileno)
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{
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        memset(fp, 0, sizeof(FILE));
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        fp->next = next;
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        fp->_flags = flags;
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        fp->_file = fileno;
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}
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/*
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 * Find a free FILE for fopen et al.
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 */
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FILE *
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__sfp()
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{
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        FILE *fp, *tmp;
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        if (!__sdidinit)
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                __sinit();
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        for (fp = &__sF[0];; fp = fp->next) {
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                if (fp->_flags == 0)
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                        goto found;
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                if (fp->next == NULL) {
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                        if ((tmp = malloc(sizeof(FILE))) == NULL)
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                                break;
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                        fp->next = tmp;
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                        fp = tmp;
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                        goto found;
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                }
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        }
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        return (NULL);
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found:
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        std(fp, NULL, 1, -1);
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        return (fp);
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}
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/*
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 * exit() calls _cleanup() through *__cleanup, set whenever we
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 * open or buffer a file.  This chicanery is done so that programs
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 * that do not use stdio need not link it all in.
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 *
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 * The name `_cleanup' is, alas, fairly well known outside stdio.
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b */
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void
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_cleanup()
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{
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        /* (void) _fwalk(fclose); */
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        (void) _fwalk(__sflush);                /* `cheating' */
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}
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/*
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 * __sinit() is called whenever stdio's internal variables must be set up.
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 */
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void
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__sinit()
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{
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        std(&__sF[0], &__sF[1], __SRD, STDIN_FILENO);
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        std(&__sF[1], &__sF[2], __SWR, STDOUT_FILENO);
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        std(&__sF[2], NULL, __SWR|__SNBF, STDERR_FILENO);
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        /* make sure we clean up on exit */
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        __cleanup = _cleanup;                /* conservative */
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        __sdidinit = 1;
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}