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. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #if defined(LIBC_SCCS) && !defined(lint) 34 static char rcsid[] = "$OpenBSD: findfp.c,v 1.5 2004/09/28 18:12:44 otto Exp $"; 35 #endif /* LIBC_SCCS and not lint */ 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 #include "local.h" 44 #include "glue.h" 45 46 int __sdidinit; 47 48 #define NDYNAMIC 10 /* add ten more whenever necessary */ 49 50 #define std(flags, file) \ 51 {0,0,0,flags,file,{0},0,__sF+file,__sclose,__sread,__sseek,__swrite} 52 /* p r w flags file _bf z cookie close read seek write */ 53 54 /* the usual - (stdin + stdout + stderr) */ 55 static FILE usual[FOPEN_MAX - 3]; 56 static struct glue uglue = { 0, FOPEN_MAX - 3, usual }; 57 58 FILE __sF[3] = { 59 std(__SRD, STDIN_FILENO), /* stdin */ 60 std(__SWR, STDOUT_FILENO), /* stdout */ 61 std(__SWR|__SNBF, STDERR_FILENO) /* stderr */ 62 }; 63 struct glue __sglue = { &uglue, 3, __sF }; 64 65 static struct glue * 66 moreglue(int n) 67 { 68 struct glue *g; 69 FILE *p; 70 static FILE empty; 71 72 g = (struct glue *)malloc(sizeof(*g) + ALIGNBYTES + n * sizeof(FILE)); 73 if (g == NULL) 74 return (NULL); 75 p = (FILE *)ALIGN(g + 1); 76 g->next = NULL; 77 g->niobs = n; 78 g->iobs = p; 79 while (--n >= 0) 80 *p++ = empty; 81 return (g); 82 } 83 84 /* 85 * Find a free FILE for fopen et al. 86 */ 87 FILE * 88 __sfp(void) 89 { 90 FILE *fp; 91 int n; 92 struct glue *g; 93 94 if (!__sdidinit) 95 __sinit(); 96 for (g = &__sglue;; g = g->next) { 97 for (fp = g->iobs, n = g->niobs; --n >= 0; fp++) 98 if (fp->_flags == 0) 99 goto found; 100 if (g->next == NULL && (g->next = moreglue(NDYNAMIC)) == NULL) 101 break; 102 } 103 return (NULL); 104 found: 105 fp->_flags = 1; /* reserve this slot; caller sets real flags */ 106 fp->_p = NULL; /* no current pointer */ 107 fp->_w = 0; /* nothing to read or write */ 108 fp->_r = 0; 109 fp->_bf._base = NULL; /* no buffer */ 110 fp->_bf._size = 0; 111 fp->_lbfsize = 0; /* not line buffered */ 112 fp->_file = -1; /* no file */ 113 /* fp->_cookie = <any>; */ /* caller sets cookie, _read/_write etc */ 114 fp->_ub._base = NULL; /* no ungetc buffer */ 115 fp->_ub._size = 0; 116 fp->_lb._base = NULL; /* no line buffer */ 117 fp->_lb._size = 0; 118 return (fp); 119 } 120 121 /* 122 * XXX. Force immediate allocation of internal memory. Not used by stdio, 123 * but documented historically for certain applications. Bad applications. 124 */ 125 void 126 f_prealloc(void) 127 { 128 struct glue *g; 129 int n; 130 131 n = getdtablesize() - FOPEN_MAX + 20; /* 20 for slop. */ 132 for (g = &__sglue; (n -= g->niobs) > 0 && g->next; g = g->next) 133 /* void */; 134 if (n > 0) 135 g->next = moreglue(n); 136 } 137 138 /* 139 * exit() and abort() call _cleanup() through the callback registered 140 * with __atexit_register_cleanup(), set whenever we open or buffer a 141 * file. This chicanery is done so that programs that do not use stdio 142 * need not link it all in. 143 * 144 * The name `_cleanup' is, alas, fairly well known outside stdio. 145 */ 146 void 147 _cleanup(void) 148 { 149 /* (void) _fwalk(fclose); */ 150 (void) _fwalk(__sflush); /* `cheating' */ 151 } 152 153 /* 154 * __sinit() is called whenever stdio's internal variables must be set up. 155 */ 156 void 157 __sinit(void) 158 { 159 /* make sure we clean up on exit */ 160 __atexit_register_cleanup(_cleanup); /* conservative */ 161 __sdidinit = 1; 162 } 163