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) 34 static char sccsid[] = "@(#)findfp.c 8.2 (Berkeley) 1/4/94"; 35 #endif /* LIBC_SCCS and not lint */ 36 #include <sys/cdefs.h> 37 __FBSDID("$FreeBSD$"); 38 39 #include <sys/param.h> 40 #include <machine/atomic.h> 41 #include <unistd.h> 42 #include <stdio.h> 43 #include <stdlib.h> 44 #include <string.h> 45 46 #include <spinlock.h> 47 48 #include "libc_private.h" 49 #include "local.h" 50 #include "glue.h" 51 52 int __sdidinit; 53 54 #define NDYNAMIC 10 /* add ten more whenever necessary */ 55 56 #define std(flags, file) \ 57 {0,0,0,flags,file,{0},0,__sF+file,__sclose,__sread,__sseek,__swrite} 58 /* p r w flags file _bf z cookie close read seek write */ 59 60 /* the usual - (stdin + stdout + stderr) */ 61 static FILE usual[FOPEN_MAX - 3]; 62 static struct glue uglue = { NULL, FOPEN_MAX - 3, usual }; 63 64 static FILE __sF[3] = { 65 std(__SRD, STDIN_FILENO), 66 std(__SWR, STDOUT_FILENO), 67 std(__SWR|__SNBF, STDERR_FILENO) 68 }; 69 70 FILE *__stdinp = &__sF[0]; 71 FILE *__stdoutp = &__sF[1]; 72 FILE *__stderrp = &__sF[2]; 73 74 struct glue __sglue = { &uglue, 3, __sF }; 75 static struct glue *lastglue = &uglue; 76 77 static struct glue * moreglue(int); 78 79 static spinlock_t thread_lock = _SPINLOCK_INITIALIZER; 80 #define THREAD_LOCK() if (__isthreaded) _SPINLOCK(&thread_lock) 81 #define THREAD_UNLOCK() if (__isthreaded) _SPINUNLOCK(&thread_lock) 82 83 #if NOT_YET 84 #define SET_GLUE_PTR(ptr, val) atomic_set_rel_ptr(&(ptr), (uintptr_t)(val)) 85 #else 86 #define SET_GLUE_PTR(ptr, val) ptr = val 87 #endif 88 89 static struct glue * 90 moreglue(n) 91 int n; 92 { 93 struct glue *g; 94 static FILE empty; 95 FILE *p; 96 97 g = (struct glue *)malloc(sizeof(*g) + ALIGNBYTES + n * sizeof(FILE)); 98 if (g == NULL) 99 return (NULL); 100 p = (FILE *)ALIGN(g + 1); 101 g->next = NULL; 102 g->niobs = n; 103 g->iobs = p; 104 while (--n >= 0) 105 *p++ = empty; 106 return (g); 107 } 108 109 /* 110 * Find a free FILE for fopen et al. 111 */ 112 FILE * 113 __sfp() 114 { 115 FILE *fp; 116 int n; 117 struct glue *g; 118 119 if (!__sdidinit) 120 __sinit(); 121 /* 122 * The list must be locked because a FILE may be updated. 123 */ 124 THREAD_LOCK(); 125 for (g = &__sglue; g != NULL; g = g->next) { 126 for (fp = g->iobs, n = g->niobs; --n >= 0; fp++) 127 if (fp->_flags == 0) 128 goto found; 129 } 130 THREAD_UNLOCK(); /* don't hold lock while malloc()ing. */ 131 if ((g = moreglue(NDYNAMIC)) == NULL) 132 return (NULL); 133 THREAD_LOCK(); /* reacquire the lock */ 134 SET_GLUE_PTR(lastglue->next, g); /* atomically append glue to list */ 135 lastglue = g; /* not atomic; only accessed when locked */ 136 fp = g->iobs; 137 found: 138 fp->_flags = 1; /* reserve this slot; caller sets real flags */ 139 THREAD_UNLOCK(); 140 fp->_p = NULL; /* no current pointer */ 141 fp->_w = 0; /* nothing to read or write */ 142 fp->_r = 0; 143 fp->_bf._base = NULL; /* no buffer */ 144 fp->_bf._size = 0; 145 fp->_lbfsize = 0; /* not line buffered */ 146 fp->_file = -1; /* no file */ 147 /* fp->_cookie = <any>; */ /* caller sets cookie, _read/_write etc */ 148 fp->_ub._base = NULL; /* no ungetc buffer */ 149 fp->_ub._size = 0; 150 fp->_lb._base = NULL; /* no line buffer */ 151 fp->_lb._size = 0; 152 /* fp->_lock = NULL; */ /* once set always set (reused) */ 153 fp->_orientation = 0; 154 memset(&fp->_mbstate, 0, sizeof(mbstate_t)); 155 return (fp); 156 } 157 158 /* 159 * XXX. Force immediate allocation of internal memory. Not used by stdio, 160 * but documented historically for certain applications. Bad applications. 161 */ 162 __warn_references(f_prealloc, 163 "warning: this program uses f_prealloc(), which is not recommended."); 164 165 void 166 f_prealloc() 167 { 168 struct glue *g; 169 int n; 170 171 n = getdtablesize() - FOPEN_MAX + 20; /* 20 for slop. */ 172 /* 173 * It should be safe to walk the list without locking it; 174 * new nodes are only added to the end and none are ever 175 * removed. 176 */ 177 for (g = &__sglue; (n -= g->niobs) > 0 && g->next; g = g->next) 178 /* void */; 179 if ((n > 0) && ((g = moreglue(n)) != NULL)) { 180 THREAD_LOCK(); 181 SET_GLUE_PTR(lastglue->next, g); 182 lastglue = g; 183 THREAD_UNLOCK(); 184 } 185 } 186 187 /* 188 * exit() calls _cleanup() through *__cleanup, set whenever we 189 * open or buffer a file. This chicanery is done so that programs 190 * that do not use stdio need not link it all in. 191 * 192 * The name `_cleanup' is, alas, fairly well known outside stdio. 193 */ 194 void 195 _cleanup() 196 { 197 /* (void) _fwalk(fclose); */ 198 (void) _fwalk(__sflush); /* `cheating' */ 199 } 200 201 /* 202 * __sinit() is called whenever stdio's internal variables must be set up. 203 */ 204 void 205 __sinit() 206 { 207 208 /* Make sure we clean up on exit. */ 209 __cleanup = _cleanup; /* conservative */ 210 __sdidinit = 1; 211 } 212