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 #if defined(LIBC_SCCS) && !defined(lint) 38 static char sccsid[] = "@(#)findfp.c 8.2 (Berkeley) 1/4/94"; 39 #endif /* LIBC_SCCS and not lint */ 40 41 #include <sys/param.h> 42 #include <unistd.h> 43 #include <stdio.h> 44 #include <errno.h> 45 #include <stdlib.h> 46 #include <string.h> 47 #include "local.h" 48 #include "glue.h" 49 50 int __sdidinit; 51 52 #define NDYNAMIC 10 /* add ten more whenever necessary */ 53 54 #define std(flags, file) \ 55 {0,0,0,flags,file,{0},0,__sF+file,__sclose,__sread,__sseek,__swrite} 56 /* p r w flags file _bf z cookie close read seek write */ 57 58 /* the usual - (stdin + stdout + stderr) */ 59 static FILE usual[FOPEN_MAX - 3]; 60 static struct glue uglue = { 0, FOPEN_MAX - 3, usual }; 61 62 FILE __sF[3] = { 63 std(__SRD, STDIN_FILENO), /* stdin */ 64 std(__SWR, STDOUT_FILENO), /* stdout */ 65 std(__SWR|__SNBF, STDERR_FILENO) /* stderr */ 66 }; 67 struct glue __sglue = { &uglue, 3, __sF }; 68 69 static struct glue * 70 moreglue(n) 71 register int n; 72 { 73 register struct glue *g; 74 register FILE *p; 75 static FILE empty; 76 77 g = (struct glue *)malloc(sizeof(*g) + ALIGNBYTES + n * sizeof(FILE)); 78 if (g == NULL) 79 return (NULL); 80 p = (FILE *)ALIGN(g + 1); 81 g->next = NULL; 82 g->niobs = n; 83 g->iobs = p; 84 while (--n >= 0) 85 *p++ = empty; 86 return (g); 87 } 88 89 /* 90 * Find a free FILE for fopen et al. 91 */ 92 FILE * 93 __sfp() 94 { 95 register FILE *fp; 96 register int n; 97 register struct glue *g; 98 99 if (!__sdidinit) 100 __sinit(); 101 for (g = &__sglue;; g = g->next) { 102 for (fp = g->iobs, n = g->niobs; --n >= 0; fp++) 103 if (fp->_flags == 0) 104 goto found; 105 if (g->next == NULL && (g->next = moreglue(NDYNAMIC)) == NULL) 106 break; 107 } 108 return (NULL); 109 found: 110 fp->_flags = 1; /* reserve this slot; caller sets real flags */ 111 fp->_p = NULL; /* no current pointer */ 112 fp->_w = 0; /* nothing to read or write */ 113 fp->_r = 0; 114 fp->_bf._base = NULL; /* no buffer */ 115 fp->_bf._size = 0; 116 fp->_lbfsize = 0; /* not line buffered */ 117 fp->_file = -1; /* no file */ 118 /* fp->_cookie = <any>; */ /* caller sets cookie, _read/_write etc */ 119 fp->_ub._base = NULL; /* no ungetc buffer */ 120 fp->_ub._size = 0; 121 fp->_lb._base = NULL; /* no line buffer */ 122 fp->_lb._size = 0; 123 return (fp); 124 } 125 126 /* 127 * XXX. Force immediate allocation of internal memory. Not used by stdio, 128 * but documented historically for certain applications. Bad applications. 129 */ 130 f_prealloc() 131 { 132 register struct glue *g; 133 int n; 134 135 n = getdtablesize() - FOPEN_MAX + 20; /* 20 for slop. */ 136 for (g = &__sglue; (n -= g->niobs) > 0 && g->next; g = g->next) 137 /* void */; 138 if (n > 0) 139 g->next = moreglue(n); 140 } 141 142 /* 143 * exit() calls _cleanup() through *__cleanup, set whenever we 144 * open or buffer a file. This chicanery is done so that programs 145 * that do not use stdio need not link it all in. 146 * 147 * The name `_cleanup' is, alas, fairly well known outside stdio. 148 */ 149 void 150 _cleanup() 151 { 152 /* (void) _fwalk(fclose); */ 153 (void) _fwalk(__sflush); /* `cheating' */ 154 } 155 156 /* 157 * __sinit() is called whenever stdio's internal variables must be set up. 158 */ 159 void 160 __sinit() 161 { 162 /* make sure we clean up on exit */ 163 __cleanup = _cleanup; /* conservative */ 164 __sdidinit = 1; 165 } 166