stdio/findfp.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*
  26  * Copyright (c) 1990, 1993
  27  *      The Regents of the University of California.  All rights reserved.
  28  *
  29  * This code is derived from software contributed to Berkeley by
  30  * Chris Torek.
  31  *
  32  * Redistribution and use in source and binary forms, with or without
  33  * modification, are permitted provided that the following conditions
  34  * are met:
  35  * 1. Redistributions of source code must retain the above copyright
  36  *    notice, this list of conditions and the following disclaimer.
  37  * 2. Redistributions in binary form must reproduce the above copyright
  38  *    notice, this list of conditions and the following disclaimer in the
  39  *    documentation and/or other materials provided with the distribution.
  40  * 3. All advertising materials mentioning features or use of this software
  41  *    must display the following acknowledgement:
  42  *      This product includes software developed by the University of
  43  *      California, Berkeley and its contributors.
  44  * 4. Neither the name of the University nor the names of its contributors
  45  *    may be used to endorse or promote products derived from this software
  46  *    without specific prior written permission.
  47  *
  48  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  49  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  50  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  51  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  52  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  53  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  54  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  55  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  56  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  57  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  58  * SUCH DAMAGE.
  59  */
  60
  61
  62 #include <sys/param.h>
  63 #include <unistd.h>
  64 #include <stdio.h>
  65 #include <errno.h>
  66 #include <stdlib.h>
  67 #include <string.h>
  68 #include "local.h"
  69 #include "glue.h"
  70
  71 int     __sdidinit = 0;
  72
  73 #define NDYNAMIC 10             /* add ten more whenever necessary */
  74
  75 #define std(flags, file) \
  76         {0,0,0,flags,file,{0},0,__sF+file,__sclose,__sread,__sseek,__swrite}
  77 /*       p r w flags file _bf z  cookie      close    read    seek    write */
  78
  79                                 /* the usual - (stdin + stdout + stderr) */
  80 static FILE usual[FOPEN_MAX - 3];
  81 static struct glue uglue = { 0, FOPEN_MAX - 3, usual };
  82
  83 FILE __sF[3] = {
  84         std(__SRD, STDIN_FILENO),               /* stdin */
  85         std(__SWR, STDOUT_FILENO),              /* stdout */
  86         std(__SWR|__SNBF, STDERR_FILENO)        /* stderr */
  87 };
  88 struct glue __sglue = { &uglue, 3, __sF };
  89
  90 static struct glue *
  91 moreglue(n)
  92         register int n;
  93 {
  94         register struct glue *g;
  95         register FILE *p;
  96         static FILE empty;
  97
  98         g = (struct glue *)malloc(sizeof(*g) + ALIGNBYTES + n * sizeof(FILE));
  99         if (g == NULL)
 100                 return (NULL);
 101         p = (FILE *)ALIGN(g + 1);
 102         g->next = NULL;
 103         g->niobs = n;
 104         g->iobs = p;
 105         while (--n >= 0)
 106                 *p++ = empty;
 107         return (g);
 108 }
 109
 110 /*
 111  * Find a free FILE for fopen et al.
 112  */
 113 FILE *
 114 __sfp()
 115 {
 116         register FILE *fp;
 117         register int n;
 118         register struct glue *g;
 119
 120         if (!__sdidinit)
 121                 __sinit();
 122         for (g = &__sglue;; g = g->next) {
 123                 for (fp = g->iobs, n = g->niobs; --n >= 0; fp++)
 124                         if (fp->_flags == 0)
 125                                 goto found;
 126                 if (g->next == NULL && (g->next = moreglue(NDYNAMIC)) == NULL)
 127                         break;
 128         }
 129         return (NULL);
 130 found:
 131         fp->_flags = 1;         /* reserve this slot; caller sets real flags */
 132         fp->_p = NULL;          /* no current pointer */
 133         fp->_w = 0;             /* nothing to read or write */
 134         fp->_r = 0;
 135         fp->_bf._base = NULL;   /* no buffer */
 136         fp->_bf._size = 0;
 137         fp->_lbfsize = 0;       /* not line buffered */
 138         fp->_file = -1;         /* no file */
 139 /*      fp->_cookie = <any>; */ /* caller sets cookie, _read/_write etc */
 140         fp->_ub._base = NULL;   /* no ungetc buffer */
 141         fp->_ub._size = 0;
 142         fp->_lb._base = NULL;   /* no line buffer */
 143         fp->_lb._size = 0;
 144         return (fp);
 145 }
 146
 147 /*
 148  * XXX.  Force immediate allocation of internal memory.  Not used by stdio,
 149  * but documented historically for certain applications.  Bad applications.
 150  */
 151 void
 152 f_prealloc()
 153 {
 154         register struct glue *g;
 155         int n;
 156
 157         n = getdtablesize() - FOPEN_MAX + 20;           /* 20 for slop. */
 158         for (g = &__sglue; (n -= g->niobs) > 0 && g->next; g = g->next)
 159                 /* void */;
 160         if (n > 0)
 161                 g->next = moreglue(n);
 162 }
 163
 164 /*
 165  * exit() calls _cleanup() through *__cleanup, set whenever we
 166  * open or buffer a file.  This chicanery is done so that programs
 167  * that do not use stdio need not link it all in.
 168  *
 169  * The name `_cleanup' is, alas, fairly well known outside stdio.
 170  */
 171 void
 172 _cleanup()
 173 {
 174         /* (void) _fwalk(fclose); */
 175         (void) _fwalk(__sflush);                /* `cheating' */
 176 }
 177
 178 /*
 179  * __sinit() is called whenever stdio's internal variables must be set up.
 180  */
 181 void
 182 __sinit()
 183 {
 184         /* make sure we clean up on exit */
 185         __cleanup = _cleanup;           /* conservative */
 186         __sdidinit = 1;
 187 }