stdio/findfp.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * Copyright (c) 1990, 1993
  24  *      The Regents of the University of California.  All rights reserved.
  25  *
  26  * This code is derived from software contributed to Berkeley by
  27  * Chris Torek.
  28  *
  29  * Redistribution and use in source and binary forms, with or without
  30  * modification, are permitted provided that the following conditions
  31  * are met:
  32  * 1. Redistributions of source code must retain the above copyright
  33  *    notice, this list of conditions and the following disclaimer.
  34  * 2. Redistributions in binary form must reproduce the above copyright
  35  *    notice, this list of conditions and the following disclaimer in the
  36  *    documentation and/or other materials provided with the distribution.
  37  * 3. All advertising materials mentioning features or use of this software
  38  *    must display the following acknowledgement:
  39  *      This product includes software developed by the University of
  40  *      California, Berkeley and its contributors.
  41  * 4. Neither the name of the University nor the names of its contributors
  42  *    may be used to endorse or promote products derived from this software
  43  *    without specific prior written permission.
  44  *
  45  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  46  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  47  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  48  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  49  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  50  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  51  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  52  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  53  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  54  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  55  * SUCH DAMAGE.
  56  */
  57
  58
  59 #include <sys/param.h>
  60 #include <unistd.h>
  61 #include <stdio.h>
  62 #include <errno.h>
  63 #include <stdlib.h>
  64 #include <string.h>
  65 #include "local.h"
  66 #include "glue.h"
  67
  68 int     __sdidinit = 0;
  69
  70 #define NDYNAMIC 10             /* add ten more whenever necessary */
  71
  72 #define std(flags, file) \
  73         {0,0,0,flags,file,{0},0,__sF+file,__sclose,__sread,__sseek,__swrite}
  74 /*       p r w flags file _bf z  cookie      close    read    seek    write */
  75
  76                                 /* the usual - (stdin + stdout + stderr) */
  77 static FILE usual[FOPEN_MAX - 3];
  78 static struct glue uglue = { 0, FOPEN_MAX - 3, usual };
  79
  80 FILE __sF[3] = {
  81         std(__SRD, STDIN_FILENO),               /* stdin */
  82         std(__SWR, STDOUT_FILENO),              /* stdout */
  83         std(__SWR|__SNBF, STDERR_FILENO)        /* stderr */
  84 };
  85 struct glue __sglue = { &uglue, 3, __sF };
  86
  87 static struct glue *
  88 moreglue(n)
  89         register int n;
  90 {
  91         register struct glue *g;
  92         register FILE *p;
  93         static FILE empty;
  94
  95         g = (struct glue *)malloc(sizeof(*g) + ALIGNBYTES + n * sizeof(FILE));
  96         if (g == NULL)
  97                 return (NULL);
  98         p = (FILE *)ALIGN(g + 1);
  99         g->next = NULL;
 100         g->niobs = n;
 101         g->iobs = p;
 102         while (--n >= 0)
 103                 *p++ = empty;
 104         return (g);
 105 }
 106
 107 /*
 108  * Find a free FILE for fopen et al.
 109  */
 110 FILE *
 111 __sfp()
 112 {
 113         register FILE *fp;
 114         register int n;
 115         register struct glue *g;
 116
 117         if (!__sdidinit)
 118                 __sinit();
 119         for (g = &__sglue;; g = g->next) {
 120                 for (fp = g->iobs, n = g->niobs; --n >= 0; fp++)
 121                         if (fp->_flags == 0)
 122                                 goto found;
 123                 if (g->next == NULL && (g->next = moreglue(NDYNAMIC)) == NULL)
 124                         break;
 125         }
 126         return (NULL);
 127 found:
 128         fp->_flags = 1;         /* reserve this slot; caller sets real flags */
 129         fp->_p = NULL;          /* no current pointer */
 130         fp->_w = 0;             /* nothing to read or write */
 131         fp->_r = 0;
 132         fp->_bf._base = NULL;   /* no buffer */
 133         fp->_bf._size = 0;
 134         fp->_lbfsize = 0;       /* not line buffered */
 135         fp->_file = -1;         /* no file */
 136 /*      fp->_cookie = <any>; */ /* caller sets cookie, _read/_write etc */
 137         fp->_ub._base = NULL;   /* no ungetc buffer */
 138         fp->_ub._size = 0;
 139         fp->_lb._base = NULL;   /* no line buffer */
 140         fp->_lb._size = 0;
 141         return (fp);
 142 }
 143
 144 /*
 145  * XXX.  Force immediate allocation of internal memory.  Not used by stdio,
 146  * but documented historically for certain applications.  Bad applications.
 147  */
 148 void
 149 f_prealloc()
 150 {
 151         register struct glue *g;
 152         int n;
 153
 154         n = getdtablesize() - FOPEN_MAX + 20;           /* 20 for slop. */
 155         for (g = &__sglue; (n -= g->niobs) > 0 && g->next; g = g->next)
 156                 /* void */;
 157         if (n > 0)
 158                 g->next = moreglue(n);
 159 }
 160
 161 /*
 162  * exit() calls _cleanup() through *__cleanup, set whenever we
 163  * open or buffer a file.  This chicanery is done so that programs
 164  * that do not use stdio need not link it all in.
 165  *
 166  * The name `_cleanup' is, alas, fairly well known outside stdio.
 167  */
 168 void
 169 _cleanup()
 170 {
 171         /* (void) _fwalk(fclose); */
 172         (void) _fwalk(__sflush);                /* `cheating' */
 173 }
 174
 175 /*
 176  * __sinit() is called whenever stdio's internal variables must be set up.
 177  */
 178 void
 179 __sinit()
 180 {
 181         /* make sure we clean up on exit */
 182         __cleanup = _cleanup;           /* conservative */
 183         __sdidinit = 1;
 184 }