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 * @(#)findfp.c 8.2 (Berkeley) 1/4/94 37 * $FreeBSD: src/lib/libc/stdio/findfp.c,v 1.7.2.3 2001/08/17 02:56:31 peter Exp $ 38 * $DragonFly: src/lib/libc/stdio/findfp.c,v 1.5 2004/06/07 20:35:41 hmp Exp $ 39 */ 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 48 #include <libc_private.h> 49 #include <spinlock.h> 50 51 #include "local.h" 52 #include "glue.h" 53 54 int __sdidinit; 55 56 #define NDYNAMIC 10 /* add ten more whenever necessary */ 57 58 #define std(flags, file) \ 59 {0,0,0,flags,file,{0},0,__sF+file,__sclose,__sread,__sseek,__swrite} 60 /* p r w flags file _bf z cookie close read seek write */ 61 62 /* the usual - (stdin + stdout + stderr) */ 63 static FILE usual[FOPEN_MAX - 3]; 64 static struct glue uglue = { 0, FOPEN_MAX - 3, usual }; 65 66 FILE __sF[3] = { 67 std(__SRD, STDIN_FILENO), /* stdin */ 68 std(__SWR, STDOUT_FILENO), /* stdout */ 69 std(__SWR|__SNBF, STDERR_FILENO) /* stderr */ 70 }; 71 struct glue __sglue = { &uglue, 3, __sF }; 72 73 /* 74 * The following kludge is done to ensure enough binary compatibility 75 * with future versions of libc. Or rather it allows us to work with 76 * libraries that have been built with a newer libc that defines these 77 * symbols and expects libc to provide them. We only have need to support 78 * i386 and alpha because they are the only "old" systems we have deployed. 79 */ 80 FILE *__stdinp = &__sF[0]; 81 FILE *__stdoutp = &__sF[1]; 82 FILE *__stderrp = &__sF[2]; 83 84 static struct glue * moreglue (int); 85 86 static spinlock_t thread_lock = _SPINLOCK_INITIALIZER; 87 #define THREAD_LOCK() if (__isthreaded) _SPINLOCK(&thread_lock) 88 #define THREAD_UNLOCK() if (__isthreaded) _SPINUNLOCK(&thread_lock) 89 90 static 91 struct glue * 92 moreglue(int n) 93 { 94 struct glue *g; 95 FILE *p; 96 static FILE empty; 97 98 g = (struct glue *)malloc(sizeof(*g) + ALIGNBYTES + n * sizeof(FILE)); 99 if (g == NULL) 100 return (NULL); 101 p = (FILE *)ALIGN(g + 1); 102 g->next = NULL; 103 g->niobs = n; 104 g->iobs = p; 105 while (--n >= 0) 106 *p++ = empty; 107 return (g); 108 } 109 110 /* 111 * Find a free FILE for fopen et al. 112 */ 113 FILE * 114 __sfp(void) 115 { 116 FILE *fp; 117 int n; 118 struct glue *g; 119 120 if (!__sdidinit) 121 __sinit(); 122 THREAD_LOCK(); 123 for (g = &__sglue;; g = g->next) { 124 for (fp = g->iobs, n = g->niobs; --n >= 0; fp++) 125 if (fp->_flags == 0) 126 goto found; 127 if (g->next == NULL && (g->next = moreglue(NDYNAMIC)) == NULL) 128 break; 129 } 130 THREAD_UNLOCK(); 131 return (NULL); 132 found: 133 fp->_flags = 1; /* reserve this slot; caller sets real flags */ 134 THREAD_UNLOCK(); 135 fp->_p = NULL; /* no current pointer */ 136 fp->_w = 0; /* nothing to read or write */ 137 fp->_r = 0; 138 fp->_bf._base = NULL; /* no buffer */ 139 fp->_bf._size = 0; 140 fp->_lbfsize = 0; /* not line buffered */ 141 fp->_file = -1; /* no file */ 142 /* fp->_cookie = <any>; */ /* caller sets cookie, _read/_write etc */ 143 fp->_ub._base = NULL; /* no ungetc buffer */ 144 fp->_ub._size = 0; 145 fp->_lb._base = NULL; /* no line buffer */ 146 fp->_lb._size = 0; 147 return (fp); 148 } 149 150 /* 151 * XXX. Force immediate allocation of internal memory. Not used by stdio, 152 * but documented historically for certain applications. Bad applications. 153 */ 154 __warn_references(f_prealloc, 155 "warning: this program uses f_prealloc(), which is not recommended."); 156 157 void 158 f_prealloc(void) 159 { 160 struct glue *g; 161 int n; 162 163 n = getdtablesize() - FOPEN_MAX + 20; /* 20 for slop. */ 164 for (g = &__sglue; (n -= g->niobs) > 0 && g->next; g = g->next) 165 /* void */; 166 if (n > 0) 167 g->next = moreglue(n); 168 } 169 170 /* 171 * exit() calls _cleanup() through *__cleanup, set whenever we 172 * open or buffer a file. This chicanery is done so that programs 173 * that do not use stdio need not link it all in. 174 * 175 * The name `_cleanup' is, alas, fairly well known outside stdio. 176 */ 177 void 178 _cleanup(void) 179 { 180 /* (void) _fwalk(fclose); */ 181 (void) _fwalk(__sflush); /* `cheating' */ 182 } 183 184 /* 185 * __sinit() is called whenever stdio's internal variables must be set up. 186 */ 187 void 188 __sinit(void) 189 { 190 /* make sure we clean up on exit */ 191 __cleanup = _cleanup; /* conservative */ 192 __sdidinit = 1; 193 } 194