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 37 #if defined(LIBC_SCCS) && !defined(lint) 38 static char sccsid[] = "@(#)findfp.c 8.2 (Berkeley) 1/4/94"; 39 #endif /* LIBC_SCCS and not lint */ 40 #include <sys/cdefs.h> 41 __FBSDID("$FreeBSD$"); 42 43 #include <sys/param.h> 44 #include <machine/atomic.h> 45 #include <unistd.h> 46 #include <stdio.h> 47 #include <stdlib.h> 48 #include <string.h> 49 50 #include <spinlock.h> 51 52 #include "libc_private.h" 53 #include "local.h" 54 #include "glue.h" 55 56 int __sdidinit; 57 58 #define NDYNAMIC 10 /* add ten more whenever necessary */ 59 60 #define std(flags, file) \ 61 {0,0,0,flags,file,{0},0,__sF+file,__sclose,__sread,__sseek,__swrite, \ 62 {0}, __sFX + file} 63 /* p r w flags file _bf z cookie close read seek write */ 64 /* _ub _extra */ 65 /* the usual - (stdin + stdout + stderr) */ 66 static FILE usual[FOPEN_MAX - 3]; 67 static struct __sFILEX usual_extra[FOPEN_MAX - 3]; 68 static struct glue uglue = { NULL, FOPEN_MAX - 3, usual }; 69 70 static struct __sFILEX __sFX[3]; 71 72 /* 73 * We can't make this 'static' until 6.0-current due to binary 74 * compatibility concerns. This also means we cannot change the 75 * sizeof(FILE) until that time either and must continue to use the 76 * __sFILEX stuff to add to FILE. 77 */ 78 FILE __sF[3] = { 79 std(__SRD, STDIN_FILENO), 80 std(__SWR, STDOUT_FILENO), 81 std(__SWR|__SNBF, STDERR_FILENO) 82 }; 83 84 /* 85 * The following kludge is done to ensure enough binary compatibility 86 * with future versions of libc. Or rather it allows us to work with 87 * libraries that have been built with a newer libc that defines these 88 * symbols and expects libc to provide them. We only have need to support 89 * i386 and alpha because they are the only "old" systems we have deployed. 90 */ 91 FILE *__stdinp = &__sF[0]; 92 FILE *__stdoutp = &__sF[1]; 93 FILE *__stderrp = &__sF[2]; 94 95 struct glue __sglue = { &uglue, 3, __sF }; 96 static struct glue *lastglue = &uglue; 97 98 static struct glue * moreglue(int); 99 100 static spinlock_t thread_lock = _SPINLOCK_INITIALIZER; 101 #define THREAD_LOCK() if (__isthreaded) _SPINLOCK(&thread_lock) 102 #define THREAD_UNLOCK() if (__isthreaded) _SPINUNLOCK(&thread_lock) 103 104 #if NOT_YET 105 #define SET_GLUE_PTR(ptr, val) atomic_set_rel_ptr(&(ptr), (uintptr_t)(val)) 106 #else 107 #define SET_GLUE_PTR(ptr, val) ptr = val 108 #endif 109 110 static struct glue * 111 moreglue(n) 112 int n; 113 { 114 struct glue *g; 115 static FILE empty; 116 static struct __sFILEX emptyx; 117 FILE *p; 118 struct __sFILEX *fx; 119 120 g = (struct glue *)malloc(sizeof(*g) + ALIGNBYTES + n * sizeof(FILE) + 121 n * sizeof(struct __sFILEX)); 122 if (g == NULL) 123 return (NULL); 124 p = (FILE *)ALIGN(g + 1); 125 fx = (struct __sFILEX *)&p[n]; 126 g->next = NULL; 127 g->niobs = n; 128 g->iobs = p; 129 while (--n >= 0) { 130 *p = empty; 131 p->_extra = fx; 132 *p->_extra = emptyx; 133 p++, fx++; 134 } 135 return (g); 136 } 137 138 /* 139 * Find a free FILE for fopen et al. 140 */ 141 FILE * 142 __sfp() 143 { 144 FILE *fp; 145 int n; 146 struct glue *g; 147 148 if (!__sdidinit) 149 __sinit(); 150 /* 151 * The list must be locked because a FILE may be updated. 152 */ 153 THREAD_LOCK(); 154 for (g = &__sglue; g != NULL; g = g->next) { 155 for (fp = g->iobs, n = g->niobs; --n >= 0; fp++) 156 if (fp->_flags == 0) 157 goto found; 158 } 159 THREAD_UNLOCK(); /* don't hold lock while malloc()ing. */ 160 if ((g = moreglue(NDYNAMIC)) == NULL) 161 return (NULL); 162 THREAD_LOCK(); /* reacquire the lock */ 163 SET_GLUE_PTR(lastglue->next, g); /* atomically append glue to list */ 164 lastglue = g; /* not atomic; only accessed when locked */ 165 fp = g->iobs; 166 found: 167 fp->_flags = 1; /* reserve this slot; caller sets real flags */ 168 THREAD_UNLOCK(); 169 fp->_p = NULL; /* no current pointer */ 170 fp->_w = 0; /* nothing to read or write */ 171 fp->_r = 0; 172 fp->_bf._base = NULL; /* no buffer */ 173 fp->_bf._size = 0; 174 fp->_lbfsize = 0; /* not line buffered */ 175 fp->_file = -1; /* no file */ 176 /* fp->_cookie = <any>; */ /* caller sets cookie, _read/_write etc */ 177 fp->_ub._base = NULL; /* no ungetc buffer */ 178 fp->_ub._size = 0; 179 fp->_lb._base = NULL; /* no line buffer */ 180 fp->_lb._size = 0; 181 /* fp->_lock = NULL; */ /* once set always set (reused) */ 182 fp->_extra->orientation = 0; 183 #ifdef notdef 184 /* Stateful encoding/decoding is not yet supported. */ 185 memset(&fp->_extra->wstate, 0, sizeof(mbstate_t)); 186 memset(&fp->_extra->rstate, 0, sizeof(mbstate_t)); 187 #endif 188 return (fp); 189 } 190 191 /* 192 * XXX. Force immediate allocation of internal memory. Not used by stdio, 193 * but documented historically for certain applications. Bad applications. 194 */ 195 __warn_references(f_prealloc, 196 "warning: this program uses f_prealloc(), which is not recommended."); 197 198 void 199 f_prealloc() 200 { 201 struct glue *g; 202 int n; 203 204 n = getdtablesize() - FOPEN_MAX + 20; /* 20 for slop. */ 205 /* 206 * It should be safe to walk the list without locking it; 207 * new nodes are only added to the end and none are ever 208 * removed. 209 */ 210 for (g = &__sglue; (n -= g->niobs) > 0 && g->next; g = g->next) 211 /* void */; 212 if ((n > 0) && ((g = moreglue(n)) != NULL)) { 213 THREAD_LOCK(); 214 SET_GLUE_PTR(lastglue->next, g); 215 lastglue = g; 216 THREAD_UNLOCK(); 217 } 218 } 219 220 /* 221 * exit() calls _cleanup() through *__cleanup, set whenever we 222 * open or buffer a file. This chicanery is done so that programs 223 * that do not use stdio need not link it all in. 224 * 225 * The name `_cleanup' is, alas, fairly well known outside stdio. 226 */ 227 void 228 _cleanup() 229 { 230 /* (void) _fwalk(fclose); */ 231 (void) _fwalk(__sflush); /* `cheating' */ 232 } 233 234 /* 235 * __sinit() is called whenever stdio's internal variables must be set up. 236 */ 237 void 238 __sinit() 239 { 240 int i; 241 242 THREAD_LOCK(); 243 if (__sdidinit == 0) { 244 /* Set _extra for the usual suspects. */ 245 for (i = 0; i < FOPEN_MAX - 3; i++) 246 usual[i]._extra = &usual_extra[i]; 247 248 /* Make sure we clean up on exit. */ 249 __cleanup = _cleanup; /* conservative */ 250 __sdidinit = 1; 251 } 252 THREAD_UNLOCK(); 253 } 254