src/system/libroot/posix/stdio/findfp.c

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