210 lines
6.0 KiB
C
210 lines
6.0 KiB
C
/*-
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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. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. 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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#if defined(LIBC_SCCS) && !defined(lint)
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#if 0
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static char sccsid[] = "@(#)findfp.c 8.2 (Berkeley) 1/4/94";
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#endif
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static const char rcsid[] =
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"$FreeBSD$";
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#endif /* LIBC_SCCS and not lint */
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#include <sys/param.h>
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#include <machine/atomic.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 <string.h>
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#include <spinlock.h>
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#include "libc_private.h"
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#include "local.h"
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#include "glue.h"
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int __sdidinit;
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#define NDYNAMIC 10 /* add ten more whenever necessary */
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#define std(flags, file) \
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{0,0,0,flags,file,{0},0,__sF+file,__sclose,__sread,__sseek,__swrite}
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/* p r w flags file _bf z cookie close read seek write */
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/* the usual - (stdin + stdout + stderr) */
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static FILE usual[FOPEN_MAX - 3];
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static struct glue uglue = { NULL, FOPEN_MAX - 3, usual };
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FILE __sF[3] = {
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std(__SRD, STDIN_FILENO), /* stdin */
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std(__SWR, STDOUT_FILENO), /* stdout */
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std(__SWR|__SNBF, STDERR_FILENO) /* stderr */
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};
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struct glue __sglue = { &uglue, 3, __sF };
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static struct glue *lastglue = &uglue;
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static struct glue * moreglue __P((int));
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static spinlock_t thread_lock = _SPINLOCK_INITIALIZER;
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#define THREAD_LOCK() if (__isthreaded) _SPINLOCK(&thread_lock)
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#define THREAD_UNLOCK() if (__isthreaded) _SPINUNLOCK(&thread_lock)
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#if NOT_YET
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#define SET_GLUE_PTR(ptr, val) atomic_set_ptr(&(ptr), (uintptr_t)(val))
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#else
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#define SET_GLUE_PTR(ptr, val) ptr = val
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#endif
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static struct glue *
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moreglue(n)
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int n;
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{
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struct glue *g;
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FILE *p;
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static FILE empty;
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g = (struct glue *)malloc(sizeof(*g) + ALIGNBYTES + n * sizeof(FILE));
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if (g == NULL)
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return (NULL);
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p = (FILE *)ALIGN(g + 1);
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g->next = NULL;
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g->niobs = n;
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g->iobs = p;
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while (--n >= 0)
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*p++ = empty;
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return (g);
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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;
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int n;
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struct glue *g;
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if (!__sdidinit)
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__sinit();
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/*
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* The list must be locked because a FILE may be updated.
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*/
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THREAD_LOCK();
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for (g = &__sglue; g != NULL; g = g->next) {
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for (fp = g->iobs, n = g->niobs; --n >= 0; fp++)
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if (fp->_flags == 0)
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goto found;
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}
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THREAD_UNLOCK(); /* don't hold lock while malloc()ing. */
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if ((g = moreglue(NDYNAMIC)) == NULL)
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return (NULL);
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THREAD_LOCK(); /* reacquire the lock */
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SET_GLUE_PTR(lastglue->next, g); /* atomically append glue to list */
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lastglue = g; /* not atomic; only accessed when locked */
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fp = g->iobs;
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found:
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fp->_flags = 1; /* reserve this slot; caller sets real flags */
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THREAD_UNLOCK();
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fp->_p = NULL; /* no current pointer */
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fp->_w = 0; /* nothing to read or write */
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fp->_r = 0;
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fp->_bf._base = NULL; /* no buffer */
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fp->_bf._size = 0;
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fp->_lbfsize = 0; /* not line buffered */
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fp->_file = -1; /* no file */
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/* fp->_cookie = <any>; */ /* caller sets cookie, _read/_write etc */
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fp->_ub._base = NULL; /* no ungetc buffer */
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fp->_ub._size = 0;
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fp->_lb._base = NULL; /* no line buffer */
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fp->_lb._size = 0;
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/* fp->_lock = NULL; */
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return (fp);
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}
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/*
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* XXX. Force immediate allocation of internal memory. Not used by stdio,
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* but documented historically for certain applications. Bad applications.
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*/
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__warn_references(f_prealloc,
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"warning: this program uses f_prealloc(), which is stupid.");
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void
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f_prealloc()
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{
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struct glue *g;
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int n;
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n = getdtablesize() - FOPEN_MAX + 20; /* 20 for slop. */
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/*
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* It should be safe to walk the list without locking it;
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* new nodes are only added to the end and none are ever
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* removed.
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*/
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for (g = &__sglue; (n -= g->niobs) > 0 && g->next; g = g->next)
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/* void */;
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if ((n > 0) && ((g = moreglue(n)) != NULL)) {
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THREAD_LOCK();
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SET_GLUE_PTR(lastglue->next, g);
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lastglue = g;
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THREAD_UNLOCK();
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}
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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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*/
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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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/* make sure we clean up on exit */
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__cleanup = _cleanup; /* conservative */
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__sdidinit = 1;
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}
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