1 /*- 2 * Copyright (c) 1990 The Regents of the University of California. 3 * 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 #if defined(LIBC_SCCS) && !defined(lint) 38 /*static char *sccsid = "from: @(#)findfp.c 5.10 (Berkeley) 2/24/91";*/ 39 static char *rcsid = "$Id: findfp.c,v 1.5 1994/12/08 22:58:47 cgd Exp $"; 40 #endif /* LIBC_SCCS and not lint */ 41 42 #include <sys/param.h> 43 #include <unistd.h> 44 #include <stdio.h> 45 #include <errno.h> 46 #include <stdlib.h> 47 #include <string.h> 48 #include "local.h" 49 #include "glue.h" 50 51 int __sdidinit; 52 53 #define NSTATIC 20 /* stdin + stdout + stderr + the usual */ 54 #define NDYNAMIC 10 /* add ten more whenever necessary */ 55 56 #define std(flags, file) \ 57 {0,0,0,flags,file,{0},0,__sF+file,__sclose,__sread,__sseek,__swrite} 58 /* p r w flags file _bf z cookie close read seek write */ 59 60 static FILE usual[NSTATIC - 3]; /* the usual */ 61 static struct glue uglue = { 0, NSTATIC - 3, usual }; 62 63 FILE __sF[3] = { 64 std(__SRD, STDIN_FILENO), /* stdin */ 65 std(__SWR, STDOUT_FILENO), /* stdout */ 66 std(__SWR|__SNBF, STDERR_FILENO) /* stderr */ 67 }; 68 struct glue __sglue = { &uglue, 3, __sF }; 69 70 static struct glue * 71 moreglue(n) 72 register int n; 73 { 74 register struct glue *g; 75 register FILE *p; 76 static FILE empty; 77 78 g = (struct glue *)malloc(sizeof(*g) + ALIGNBYTES + n * sizeof(FILE)); 79 if (g == NULL) 80 return (NULL); 81 p = (FILE *)ALIGN(g + 1); 82 g->next = NULL; 83 g->niobs = n; 84 g->iobs = p; 85 while (--n >= 0) 86 *p++ = empty; 87 return (g); 88 } 89 90 /* 91 * Find a free FILE for fopen et al. 92 */ 93 FILE * 94 __sfp() 95 { 96 register FILE *fp; 97 register int n; 98 register struct glue *g; 99 100 if (!__sdidinit) 101 __sinit(); 102 for (g = &__sglue;; g = g->next) { 103 for (fp = g->iobs, n = g->niobs; --n >= 0; fp++) 104 if (fp->_flags == 0) 105 goto found; 106 if (g->next == NULL && (g->next = moreglue(NDYNAMIC)) == NULL) 107 break; 108 } 109 return (NULL); 110 found: 111 fp->_flags = 1; /* reserve this slot; caller sets real flags */ 112 fp->_p = NULL; /* no current pointer */ 113 fp->_w = 0; /* nothing to read or write */ 114 fp->_r = 0; 115 fp->_bf._base = NULL; /* no buffer */ 116 fp->_bf._size = 0; 117 fp->_lbfsize = 0; /* not line buffered */ 118 fp->_file = -1; /* no file */ 119 /* fp->_cookie = <any>; */ /* caller sets cookie, _read/_write etc */ 120 fp->_ub._base = NULL; /* no ungetc buffer */ 121 fp->_ub._size = 0; 122 fp->_lb._base = NULL; /* no line buffer */ 123 fp->_lb._size = 0; 124 return (fp); 125 } 126 127 /* 128 * XXX. Force immediate allocation of internal memory. Not used by stdio, 129 * but documented historically for certain applications. Bad applications. 130 */ 131 void 132 f_prealloc() 133 { 134 int n = getdtablesize() - NSTATIC + 20; /* 20 for slop */ 135 register struct glue *g; 136 137 for (g = &__sglue; (n -= g->niobs) > 0 && g->next; g = g->next) 138 /* void */; 139 if (n > 0) 140 g->next = moreglue(n); 141 } 142 143 /* 144 * exit() calls _cleanup() through *__cleanup, set whenever we 145 * open or buffer a file. This chicanery is done so that programs 146 * that do not use stdio need not link it all in. 147 * 148 * The name `_cleanup' is, alas, fairly well known outside stdio. 149 */ 150 void 151 _cleanup() 152 { 153 /* (void) _fwalk(fclose); */ 154 (void) _fwalk(__sflush); /* `cheating' */ 155 } 156 157 /* 158 * __sinit() is called whenever stdio's internal variables must be set up. 159 */ 160 void 161 __sinit() 162 { 163 /* make sure we clean up on exit */ 164 __cleanup = _cleanup; /* conservative */ 165 __sdidinit = 1; 166 } 167