1 /* $OpenBSD: findfp.c,v 1.9 2005/08/08 08:05:36 espie Exp $ */ 2 /*- 3 * Copyright (c) 1990, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * Chris Torek. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #include <sys/param.h> 35 #include <unistd.h> 36 #include <stdio.h> 37 #include <errno.h> 38 #include <stdlib.h> 39 #include <string.h> 40 #include "local.h" 41 #include "glue.h" 42 #include "thread_private.h" 43 44 int __sdidinit; 45 46 #define NDYNAMIC 10 /* add ten more whenever necessary */ 47 48 #define std(flags, file) \ 49 {0,0,0,flags,file,{0,0},0,__sF+file,__sclose,__sread,__sseek,__swrite, \ 50 {(unsigned char *)(__sFext+file), 0},NULL,0,{0,0,0},{0},{0,0},0,0} 51 /* p r w flags file _bf z cookie close read seek write 52 ext */ 53 54 /* the usual - (stdin + stdout + stderr) */ 55 static FILE usual[FOPEN_MAX - 3]; 56 static struct __sfileext usualext[FOPEN_MAX - 3]; 57 static struct glue uglue = { 0, FOPEN_MAX - 3, usual }; 58 static struct glue *lastglue = &uglue; 59 _THREAD_PRIVATE_MUTEX(__sfp_mutex); 60 61 static struct __sfileext __sFext[3] = { 62 _FILEEXT_INITIALIZER, 63 _FILEEXT_INITIALIZER, 64 _FILEEXT_INITIALIZER, 65 }; 66 67 FILE __sF[3] = { 68 std(__SRD, STDIN_FILENO), /* stdin */ 69 std(__SWR, STDOUT_FILENO), /* stdout */ 70 std(__SWR|__SNBF, STDERR_FILENO) /* stderr */ 71 }; 72 struct glue __sglue = { &uglue, 3, __sF }; 73 74 static struct glue * 75 moreglue(int n) 76 { 77 struct glue *g; 78 FILE *p; 79 struct __sfileext *pext; 80 static FILE empty; 81 char *data; 82 83 data = malloc(sizeof(*g) + ALIGNBYTES + n * sizeof(FILE) 84 + n * sizeof(struct __sfileext)); 85 if (data == NULL) 86 return (NULL); 87 g = (struct glue *)data; 88 p = (FILE *)ALIGN(data + sizeof(*g)); 89 pext = (struct __sfileext *) 90 (ALIGN(data + sizeof(*g)) + n * sizeof(FILE)); 91 g->next = NULL; 92 g->niobs = n; 93 g->iobs = p; 94 while (--n >= 0) { 95 *p = empty; 96 _FILEEXT_SETUP(p, pext); 97 p++; 98 pext++; 99 } 100 return (g); 101 } 102 103 /* 104 * Find a free FILE for fopen et al. 105 */ 106 FILE * 107 __sfp(void) 108 { 109 FILE *fp; 110 int n; 111 struct glue *g; 112 113 if (!__sdidinit) 114 __sinit(); 115 116 _THREAD_PRIVATE_MUTEX_LOCK(__sfp_mutex); 117 for (g = &__sglue; g != NULL; g = g->next) { 118 for (fp = g->iobs, n = g->niobs; --n >= 0; fp++) 119 if (fp->_flags == 0) 120 goto found; 121 } 122 123 /* release lock while mallocing */ 124 _THREAD_PRIVATE_MUTEX_UNLOCK(__sfp_mutex); 125 if ((g = moreglue(NDYNAMIC)) == NULL) 126 return (NULL); 127 _THREAD_PRIVATE_MUTEX_LOCK(__sfp_mutex); 128 lastglue->next = g; 129 lastglue = g; 130 fp = g->iobs; 131 found: 132 fp->_flags = 1; /* reserve this slot; caller sets real flags */ 133 _THREAD_PRIVATE_MUTEX_UNLOCK(__sfp_mutex); 134 fp->_p = NULL; /* no current pointer */ 135 fp->_w = 0; /* nothing to read or write */ 136 fp->_r = 0; 137 fp->_bf._base = NULL; /* no buffer */ 138 fp->_bf._size = 0; 139 fp->_lbfsize = 0; /* not line buffered */ 140 fp->_file = -1; /* no file */ 141 /* fp->_cookie = <any>; */ /* caller sets cookie, _read/_write etc */ 142 fp->_lb._base = NULL; /* no line buffer */ 143 fp->_lb._size = 0; 144 _FILEEXT_INIT(fp); 145 return (fp); 146 } 147 148 #if 0 149 #define getdtablesize() sysconf(_SC_OPEN_MAX) 150 151 /* 152 * XXX. Force immediate allocation of internal memory. Not used by stdio, 153 * but documented historically for certain applications. Bad applications. 154 */ 155 void 156 f_prealloc(void) 157 { 158 struct glue *g; 159 int n; 160 161 n = getdtablesize() - FOPEN_MAX + 20; /* 20 for slop. */ 162 for (g = &__sglue; (n -= g->niobs) > 0 && g->next; g = g->next) 163 /* void */; 164 if (n > 0 && ((g = moreglue(n)) != NULL)) { 165 _THREAD_PRIVATE_MUTEX_LOCK(__sfp_mutex); 166 lastglue->next = g; 167 lastglue = g; 168 _THREAD_PRIVATE_MUTEX_UNLOCK(__sfp_mutex); 169 } 170 } 171 #endif 172 173 /* 174 * exit() and abort() call _cleanup() through the callback registered 175 * with __atexit_register_cleanup(), set whenever we open or buffer a 176 * file. This chicanery is done so that programs that do not use stdio 177 * need not link it all in. 178 * 179 * The name `_cleanup' is, alas, fairly well known outside stdio. 180 */ 181 void 182 _cleanup(void) 183 { 184 /* (void) _fwalk(fclose); */ 185 (void) _fwalk(__sflush); /* `cheating' */ 186 } 187 188 /* 189 * __sinit() is called whenever stdio's internal variables must be set up. 190 */ 191 void 192 __sinit(void) 193 { 194 _THREAD_PRIVATE_MUTEX(__sinit_mutex); 195 int i; 196 197 _THREAD_PRIVATE_MUTEX_LOCK(__sinit_mutex); 198 if (__sdidinit) 199 goto out; /* bail out if caller lost the race */ 200 for (i = 0; i < FOPEN_MAX - 3; i++) { 201 _FILEEXT_SETUP(usual+i, usualext+i); 202 } 203 /* make sure we clean up on exit */ 204 __atexit_register_cleanup(_cleanup); /* conservative */ 205 __sdidinit = 1; 206 out: 207 _THREAD_PRIVATE_MUTEX_UNLOCK(__sinit_mutex); 208 } 209
