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 * 4. 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) 34static char sccsid[] = "@(#)findfp.c 8.2 (Berkeley) 1/4/94"; 35#endif /* LIBC_SCCS and not lint */ 36#include <sys/cdefs.h> 37__FBSDID("$FreeBSD: src/lib/libc/stdio/findfp.c,v 1.34 2009/12/05 19:31:38 ed Exp $"); 38 39#include <TargetConditionals.h> 40 41#include <sys/param.h> 42#include <machine/atomic.h> 43#include <unistd.h> 44#include <stdio.h> 45#include <stdlib.h> 46#include <string.h> 47#include <libkern/OSAtomic.h> 48#include <errno.h> 49 50#include <pthread.h> 51#include <spinlock.h> 52 53#include "libc_private.h" 54#include "local.h" 55#include "glue.h" 56 57int __sdidinit; 58 59#if !TARGET_OS_EMBEDDED 60#define NDYNAMIC 10 /* add ten more whenever necessary */ 61#else 62#define NDYNAMIC 1 /* add one at a time on embedded */ 63#endif 64 65#define std(flags, file) { \ 66 ._flags = (flags), \ 67 ._file = (file), \ 68 ._cookie = __sF + (file), \ 69 ._close = __sclose, \ 70 ._read = __sread, \ 71 ._seek = __sseek, \ 72 ._write = __swrite, \ 73 ._extra = __sFX + file, \ 74} 75#define __sFXInit {.fl_mutex = PTHREAD_MUTEX_INITIALIZER} 76 /* set counted */ 77#define __sFXInit3 {.fl_mutex = PTHREAD_MUTEX_INITIALIZER, .counted = 1} 78 79static int __scounted; /* streams counted against STREAM_MAX */ 80static int __stream_max; 81 82#if !TARGET_OS_EMBEDDED 83/* usual and usual_extra are data pigs. See 7929728. For embedded we should 84 * always allocate dynamically, and probably should for desktop too. */ 85 /* the usual - (stdin + stdout + stderr) */ 86static FILE usual[FOPEN_MAX - 3]; 87static struct __sFILEX usual_extra[FOPEN_MAX - 3]; 88static struct glue uglue = { NULL, FOPEN_MAX - 3, usual }; 89#endif /* !TARGET_OS_EMBEDDED */ 90 91static struct __sFILEX __sFX[3] = {__sFXInit3, __sFXInit3, __sFXInit3}; 92 93/* 94 * We can't make this 'static' due to binary compatibility concerns. 95 * This also means we cannot change the sizeof(FILE) and must continue to 96 * use the __sFILEX stuff to add to FILE. 97 */ 98FILE __sF[3] = { 99 std(__SRD, STDIN_FILENO), 100 std(__SWR, STDOUT_FILENO), 101 std(__SWR|__SNBF, STDERR_FILENO) 102}; 103 104FILE *__stdinp = &__sF[0]; 105FILE *__stdoutp = &__sF[1]; 106FILE *__stderrp = &__sF[2]; 107 108#if !TARGET_OS_EMBEDDED 109struct glue __sglue = { &uglue, 3, __sF }; 110static struct glue *lastglue = &uglue; 111#else 112struct glue __sglue = { NULL, 3, __sF }; 113static struct glue *lastglue = &__sglue; 114#endif 115 116static struct glue * moreglue(int); 117 118static spinlock_t thread_lock = _SPINLOCK_INITIALIZER; 119#define THREAD_LOCK() if (__isthreaded) _SPINLOCK(&thread_lock) 120#define THREAD_UNLOCK() if (__isthreaded) _SPINUNLOCK(&thread_lock) 121 122#if NOT_YET 123#define SET_GLUE_PTR(ptr, val) atomic_set_rel_ptr(&(ptr), (uintptr_t)(val)) 124#else 125#define SET_GLUE_PTR(ptr, val) ptr = val 126#endif 127 128static struct glue * 129moreglue(n) 130 int n; 131{ 132 struct glue *g; 133 static const FILE empty; 134 FILE *p; 135 static const struct __sFILEX emptyx = __sFXInit; 136 struct __sFILEX *fx; 137 138 g = (struct glue *)malloc(sizeof(*g) + ALIGNBYTES + n * sizeof(FILE) + 139 n * sizeof(struct __sFILEX)); 140 if (g == NULL) 141 return (NULL); 142 p = (FILE *)ALIGN(g + 1); 143 fx = (struct __sFILEX *)&p[n]; 144 g->next = NULL; 145 g->niobs = n; 146 g->iobs = p; 147 148 while (--n >= 0) { 149 *p = empty; 150 p->_extra = fx; 151 *p->_extra = emptyx; 152 p++, fx++; 153 } 154 return (g); 155} 156 157/* 158 * Find a free FILE for fopen et al. 159 */ 160FILE * 161__sfp(int count) 162{ 163 FILE *fp; 164 int n; 165 struct glue *g; 166 167 if (!__sdidinit) 168 __sinit(); 169 170 if (count) { 171 if (__scounted >= __stream_max) { 172 THREAD_UNLOCK(); 173 errno = EMFILE; 174 return NULL; 175 } 176 OSAtomicIncrement32(&__scounted); 177 } 178 /* 179 * The list must be locked because a FILE may be updated. 180 */ 181 THREAD_LOCK(); 182 for (g = &__sglue; g != NULL; g = g->next) { 183 for (fp = g->iobs, n = g->niobs; --n >= 0; fp++) 184 if (fp->_flags == 0) 185 goto found; 186 } 187 THREAD_UNLOCK(); /* don't hold lock while malloc()ing. */ 188 if ((g = moreglue(NDYNAMIC)) == NULL) 189 return (NULL); 190 THREAD_LOCK(); /* reacquire the lock */ 191 SET_GLUE_PTR(lastglue->next, g); /* atomically append glue to list */ 192 lastglue = g; /* not atomic; only accessed when locked */ 193 fp = g->iobs; 194found: 195 fp->_flags = 1; /* reserve this slot; caller sets real flags */ 196 THREAD_UNLOCK(); 197 fp->_p = NULL; /* no current pointer */ 198 fp->_w = 0; /* nothing to read or write */ 199 fp->_r = 0; 200 fp->_bf._base = NULL; /* no buffer */ 201 fp->_bf._size = 0; 202 fp->_lbfsize = 0; /* not line buffered */ 203 fp->_file = -1; /* no file */ 204/* fp->_cookie = <any>; */ /* caller sets cookie, _read/_write etc */ 205 fp->_ub._base = NULL; /* no ungetc buffer */ 206 fp->_ub._size = 0; 207 fp->_lb._base = NULL; /* no line buffer */ 208 fp->_lb._size = 0; 209/* fp->_lock = NULL; */ /* once set always set (reused) */ 210 INITEXTRA(fp); 211 fp->_extra->counted = count ? 1 : 0; 212 return (fp); 213} 214 215/* 216 * Mark as free and update count as needed 217 */ 218__private_extern__ void 219__sfprelease(FILE *fp) 220{ 221 if (fp->_counted) { 222 OSAtomicDecrement32(&__scounted); 223 fp->_counted = 0; 224 } 225 fp->_flags = 0; 226} 227 228/* 229 * XXX. Force immediate allocation of internal memory. Not used by stdio, 230 * but documented historically for certain applications. Bad applications. 231 */ 232__warn_references(f_prealloc, 233 "warning: this program uses f_prealloc(), which is not recommended."); 234 235void 236f_prealloc(void) 237{ 238 struct glue *g; 239 int n; 240 241 n = getdtablesize() - FOPEN_MAX + 20; /* 20 for slop. */ 242 /* 243 * It should be safe to walk the list without locking it; 244 * new nodes are only added to the end and none are ever 245 * removed. 246 */ 247 for (g = &__sglue; (n -= g->niobs) > 0 && g->next; g = g->next) 248 /* void */; 249 if ((n > 0) && ((g = moreglue(n)) != NULL)) { 250 THREAD_LOCK(); 251 SET_GLUE_PTR(lastglue->next, g); 252 lastglue = g; 253 THREAD_UNLOCK(); 254 } 255} 256 257/* 258 * exit() calls _cleanup() through *__cleanup, set whenever we 259 * open or buffer a file. This chicanery is done so that programs 260 * that do not use stdio need not link it all in. 261 * 262 * The name `_cleanup' is, alas, fairly well known outside stdio. 263 */ 264void 265_cleanup() 266{ 267 /* (void) _fwalk(fclose); */ 268 (void) _fwalk(__sflush); /* `cheating' */ 269} 270 271/* 272 * __sinit() is called whenever stdio's internal variables must be set up. 273 */ 274void 275__sinit() 276{ 277 THREAD_LOCK(); 278 if (__sdidinit == 0) { 279#if !TARGET_OS_EMBEDDED 280 int i; 281#endif 282 /* Make sure we clean up on exit. */ 283 __cleanup = _cleanup; /* conservative */ 284 __stream_max = sysconf(_SC_STREAM_MAX); 285 __scounted = 3; /* std{in,out,err} already exists */ 286 287#if !TARGET_OS_EMBEDDED 288 /* Set _extra for the usual suspects. */ 289 for (i = 0; i < FOPEN_MAX - 3; i++) { 290 usual[i]._extra = &usual_extra[i]; 291 INITEXTRA(&usual[i]); 292 } 293#endif 294 295 __sdidinit = 1; 296 } 297 THREAD_UNLOCK(); 298} 299