lib/libc/stdio/findfp.c

   1 /*      $NetBSD: findfp.c,v 1.28 2012/03/27 15:05:42 christos Exp $     */
   2
   3 /*-
   4  * Copyright (c) 1990, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * This code is derived from software contributed to Berkeley by
   8  * Chris Torek.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #include <sys/cdefs.h>
  36 #if defined(LIBC_SCCS) && !defined(lint)
  37 #if 0
  38 static char sccsid[] = "@(#)findfp.c    8.2 (Berkeley) 1/4/94";
  39 #else
  40 __RCSID("$NetBSD: findfp.c,v 1.28 2012/03/27 15:05:42 christos Exp $");
  41 #endif
  42 #endif /* LIBC_SCCS and not lint */
  43
  44 #include "namespace.h"
  45 #include <sys/param.h>
  46 #include <unistd.h>
  47 #include <stdio.h>
  48 #include <errno.h>
  49 #include <stdlib.h>
  50 #include <string.h>
  51 #include "reentrant.h"
  52 #include "local.h"
  53 #include "glue.h"
  54
  55 int     __sdidinit;
  56
  57 #define NDYNAMIC 10             /* add ten more whenever necessary */
  58
  59 #if !defined(_LIBMINC) && !defined(__kernel__)
  60
  61 #define std(flags, file) { \
  62         ._p = NULL, \
  63         ._r = 0, \
  64         ._w = 0, \
  65         ._flags = (flags), \
  66         ._file = (file),  \
  67         ._bf = { ._base = NULL, ._size = 0 }, \
  68         ._lbfsize = 0,  \
  69         ._cookie = __sF + (file), \
  70         ._close = __sclose, \
  71         ._read = __sread, \
  72         ._seek = __sseek, \
  73         ._write = __swrite, \
  74         ._ext = { ._base = (void *)(__sFext + (file)), ._size = 0 }, \
  75         ._up = NULL, \
  76         ._ur = 0, \
  77         ._ubuf = { [0] = '\0', [1] = '\0', [2] = '\0' }, \
  78         ._nbuf = { [0] = '\0' }, \
  79         ._flush = NULL, \
  80         ._lb_unused = { '\0' }, \
  81         ._blksize = 0, \
  82         ._offset = (off_t)0, \
  83 }
  84
  85 #else
  86
  87 #define std(flags, file) { \
  88         ._p = NULL, \
  89         ._r = 0, \
  90         ._w = 0, \
  91         ._flags = (flags), \
  92         ._file = (file),  \
  93         ._bf = { ._base = NULL, ._size = 0 }, \
  94         ._lbfsize = 0,  \
  95         ._cookie = __sF + (file), \
  96         ._close = NULL, \
  97         ._read = NULL, \
  98         ._seek = NULL, \
  99         ._write = NULL, \
 100         ._ext = { ._base = (void *)(__sFext + (file)), ._size = 0 }, \
 101         ._up = NULL, \
 102         ._ur = 0, \
 103         ._ubuf = { [0] = '\0', [1] = '\0', [2] = '\0' }, \
 104         ._nbuf = { [0] = '\0' }, \
 105         ._flush = NULL, \
 106         ._lb_unused = { '\0' }, \
 107         ._blksize = 0, \
 108         ._offset = (off_t)0, \
 109 }
 110
 111 #endif /* !defined(_LIBMINC) && !defined(__kernel__) */
 112
 113 #if !defined(__kernel__)
 114                                 /* the usual - (stdin + stdout + stderr) */
 115 static FILE usual[FOPEN_MAX - 3];
 116 static struct __sfileext usualext[FOPEN_MAX - 3];
 117 static struct glue uglue = { 0, FOPEN_MAX - 3, usual };
 118 #endif /* !defined(__kernel__) */
 119
 120 #if defined(_REENTRANT) && !defined(__lint__) /* XXX lint is busted */
 121 #define STDEXT { ._lock = MUTEX_INITIALIZER, ._lockcond = COND_INITIALIZER }
 122 struct __sfileext __sFext[3] = { STDEXT,
 123                                  STDEXT,
 124                                  STDEXT};
 125 #else
 126 struct __sfileext __sFext[3];
 127 #endif
 128
 129 FILE __sF[3] = {
 130         std(__SRD, STDIN_FILENO),               /* stdin */
 131         std(__SWR, STDOUT_FILENO),              /* stdout */
 132         std(__SWR|__SNBF, STDERR_FILENO)        /* stderr */
 133 };
 134
 135 #if !defined(__kernel__)
 136 struct glue __sglue = { &uglue, 3, __sF };
 137
 138 void f_prealloc(void);
 139
 140 #ifdef _REENTRANT
 141 rwlock_t __sfp_lock = RWLOCK_INITIALIZER;
 142 #endif
 143
 144 static struct glue *
 145 moreglue(int n)
 146 {
 147         struct glue *g;
 148         FILE *p;
 149         struct __sfileext *pext;
 150         static FILE empty;
 151
 152         g = malloc(sizeof(*g) + ALIGNBYTES + n * sizeof(FILE)
 153             + n * sizeof(struct __sfileext));
 154         if (g == NULL)
 155                 return NULL;
 156         p = (FILE *)ALIGN((u_long)(g + 1));
 157         g->next = NULL;
 158         g->niobs = n;
 159         g->iobs = p;
 160         pext = (void *)(p + n);
 161         while (--n >= 0) {
 162                 *p = empty;
 163                 _FILEEXT_SETUP(p, pext);
 164                 p++;
 165                 pext++;
 166         }
 167         return g;
 168 }
 169
 170 void
 171 __sfpinit(FILE *fp)
 172 {
 173         fp->_flags = 1;         /* reserve this slot; caller sets real flags */
 174         fp->_p = NULL;          /* no current pointer */
 175         fp->_w = 0;             /* nothing to read or write */
 176         fp->_r = 0;
 177         fp->_bf._base = NULL;   /* no buffer */
 178         fp->_bf._size = 0;
 179         fp->_lbfsize = 0;       /* not line buffered */
 180         fp->_file = -1;         /* no file */
 181 /*      fp->_cookie = <any>; */ /* caller sets cookie, _read/_write etc */
 182         fp->_flush = NULL;      /* default flush */
 183         _UB(fp)._base = NULL;   /* no ungetc buffer */
 184         _UB(fp)._size = 0;
 185         memset(WCIO_GET(fp), 0, sizeof(struct wchar_io_data));
 186 }
 187
 188 /*
 189  * Find a free FILE for fopen et al.
 190  */
 191 FILE *
 192 __sfp(void)
 193 {
 194         FILE *fp;
 195         int n;
 196         struct glue *g;
 197
 198         if (!__sdidinit)
 199                 __sinit();
 200
 201         rwlock_wrlock(&__sfp_lock);
 202         for (g = &__sglue;; g = g->next) {
 203                 for (fp = g->iobs, n = g->niobs; --n >= 0; fp++)
 204                         if (fp->_flags == 0)
 205                                 goto found;
 206                 if (g->next == NULL && (g->next = moreglue(NDYNAMIC)) == NULL)
 207                         break;
 208         }
 209         rwlock_unlock(&__sfp_lock);
 210         return NULL;
 211 found:
 212         __sfpinit(fp);
 213         rwlock_unlock(&__sfp_lock);
 214         return fp;
 215 }
 216
 217 /*
 218  * XXX.  Force immediate allocation of internal memory.  Not used by stdio,
 219  * but documented historically for certain applications.  Bad applications.
 220  */
 221 void
 222 f_prealloc(void)
 223 {
 224 #if !defined(_LIBMINC)
 225         struct glue *g;
 226         int n;
 227
 228         n = (int)sysconf(_SC_OPEN_MAX) - FOPEN_MAX + 20; /* 20 for slop. */
 229         for (g = &__sglue; (n -= g->niobs) > 0 && g->next; g = g->next)
 230                 continue;
 231         if (n > 0)
 232                 g->next = moreglue(n);
 233 #endif /* !defined(_LIBMINC) */
 234 }
 235
 236 /*
 237  * exit() calls _cleanup() through *__cleanup, set whenever we
 238  * open or buffer a file.  This chicanery is done so that programs
 239  * that do not use stdio need not link it all in.
 240  *
 241  * The name `_cleanup' is, alas, fairly well known outside stdio.
 242  */
 243 void
 244 _cleanup(void)
 245 {
 246 #if !defined(_LIBMINC)
 247         /* (void) _fwalk(fclose); */
 248         (void) fflush(NULL);                    /* `cheating' */
 249 #endif /* !defined(_LIBMINC) */
 250 }
 251
 252 /*
 253  * __sinit() is called whenever stdio's internal variables must be set up.
 254  */
 255 void
 256 __sinit(void)
 257 {
 258         int i;
 259
 260         for (i = 0; i < FOPEN_MAX - 3; i++)
 261                 _FILEEXT_SETUP(&usual[i], &usualext[i]);
 262
 263         /* make sure we clean up on exit */
 264         __cleanup = _cleanup;           /* conservative */
 265         __sdidinit = 1;
 266 }
 267 #endif /* !defined(__kernel__) */