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 1.4 2003/06/02 20:18:37 millert 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(n) 67 register int n; 68 { 69 register struct glue *g; 70 register FILE *p; 71 static FILE empty; 72 73 g = (struct glue *)malloc(sizeof(*g) + ALIGNBYTES + n * sizeof(FILE)); 74 if (g == NULL) 75 return (NULL); 76 p = (FILE *)ALIGN(g + 1); 77 g->next = NULL; 78 g->niobs = n; 79 g->iobs = p; 80 while (--n >= 0) 81 *p++ = empty; 82 return (g); 83 } 84 85 /* 86 * Find a free FILE for fopen et al. 87 */ 88 FILE * 89 __sfp() 90 { 91 register FILE *fp; 92 register int n; 93 register struct glue *g; 94 95 if (!__sdidinit) 96 __sinit(); 97 for (g = &__sglue;; g = g->next) { 98 for (fp = g->iobs, n = g->niobs; --n >= 0; fp++) 99 if (fp->_flags == 0) 100 goto found; 101 if (g->next == NULL && (g->next = moreglue(NDYNAMIC)) == NULL) 102 break; 103 } 104 return (NULL); 105 found: 106 fp->_flags = 1; /* reserve this slot; caller sets real flags */ 107 fp->_p = NULL; /* no current pointer */ 108 fp->_w = 0; /* nothing to read or write */ 109 fp->_r = 0; 110 fp->_bf._base = NULL; /* no buffer */ 111 fp->_bf._size = 0; 112 fp->_lbfsize = 0; /* not line buffered */ 113 fp->_file = -1; /* no file */ 114 /* fp->_cookie = <any>; */ /* caller sets cookie, _read/_write etc */ 115 fp->_ub._base = NULL; /* no ungetc buffer */ 116 fp->_ub._size = 0; 117 fp->_lb._base = NULL; /* no line buffer */ 118 fp->_lb._size = 0; 119 return (fp); 120 } 121 122 /* 123 * XXX. Force immediate allocation of internal memory. Not used by stdio, 124 * but documented historically for certain applications. Bad applications. 125 */ 126 void 127 f_prealloc() 128 { 129 register struct glue *g; 130 int n; 131 132 n = getdtablesize() - FOPEN_MAX + 20; /* 20 for slop. */ 133 for (g = &__sglue; (n -= g->niobs) > 0 && g->next; g = g->next) 134 /* void */; 135 if (n > 0) 136 g->next = moreglue(n); 137 } 138 139 /* 140 * exit() and abort() call _cleanup() through the callback registered 141 * with __atexit_register_cleanup(), set whenever we open or buffer a 142 * file. This chicanery is done so that programs that do not use stdio 143 * need not link it all in. 144 * 145 * The name `_cleanup' is, alas, fairly well known outside stdio. 146 */ 147 void 148 _cleanup() 149 { 150 /* (void) _fwalk(fclose); */ 151 (void) _fwalk(__sflush); /* `cheating' */ 152 } 153 154 /* 155 * __sinit() is called whenever stdio's internal variables must be set up. 156 */ 157 void 158 __sinit() 159 { 160 /* make sure we clean up on exit */ 161 __atexit_register_cleanup(_cleanup); /* conservative */ 162 __sdidinit = 1; 163 } 164