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. 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 <stdint.h> 45 #include <string.h> 46 47 #include <spinlock.h> 48 49 #include "libc_private.h" 50 #include "local.h" 51 #include "glue.h" 52 53 int __sdidinit; 54 55 #define NDYNAMIC 10 /* add ten more whenever necessary */ 56 57 #define std(flags, file) { \ 58 ._flags = (flags), \ 59 ._file = (file), \ 60 ._cookie = __sF + (file), \ 61 ._close = __sclose, \ 62 ._read = __sread, \ 63 ._seek = __sseek, \ 64 ._write = __swrite, \ 65 ._fl_mutex = PTHREAD_MUTEX_INITIALIZER, \ 66 } 67 /* the usual - (stdin + stdout + stderr) */ 68 static FILE usual[FOPEN_MAX - 3]; 69 static struct glue uglue = { NULL, FOPEN_MAX - 3, usual }; 70 71 static FILE __sF[3] = { 72 std(__SRD, STDIN_FILENO), 73 std(__SWR, STDOUT_FILENO), 74 std(__SWR|__SNBF, STDERR_FILENO) 75 }; 76 77 FILE *__stdinp = &__sF[0]; 78 FILE *__stdoutp = &__sF[1]; 79 FILE *__stderrp = &__sF[2]; 80 81 struct glue __sglue = { &uglue, 3, __sF }; 82 static struct glue *lastglue = &uglue; 83 84 static struct glue * moreglue(int); 85 86 spinlock_t __stdio_thread_lock = _SPINLOCK_INITIALIZER; 87 88 #if NOT_YET 89 #define SET_GLUE_PTR(ptr, val) atomic_set_rel_ptr(&(ptr), (uintptr_t)(val)) 90 #else 91 #define SET_GLUE_PTR(ptr, val) ptr = val 92 #endif 93 94 static struct glue * 95 moreglue(int n) 96 { 97 struct glue *g; 98 static FILE empty = { ._fl_mutex = PTHREAD_MUTEX_INITIALIZER }; 99 FILE *p; 100 size_t align; 101 102 /* 103 * FILE has a mbstate_t variable. This variable tries to be int64_t 104 * aligned through its definition. int64_t may be larger than void *, 105 * which is the size traditionally used for ALIGNBYTES. So, use our own 106 * rounding instead of the MI ALIGN macros. If for some reason 107 * ALIGNBYTES is larger than int64_t, respect that too. There appears to 108 * be no portable way to ask for FILE's alignment requirements other 109 * than just knowing here. 110 */ 111 align = MAX(ALIGNBYTES, sizeof(int64_t)); 112 g = (struct glue *)malloc(sizeof(*g) + align + n * sizeof(FILE)); 113 if (g == NULL) 114 return (NULL); 115 p = (FILE *)roundup((uintptr_t)(g + 1), align); 116 g->next = NULL; 117 g->niobs = n; 118 g->iobs = p; 119 while (--n >= 0) 120 *p++ = empty; 121 return (g); 122 } 123 124 /* 125 * Find a free FILE for fopen et al. 126 */ 127 FILE * 128 __sfp(void) 129 { 130 FILE *fp; 131 int n; 132 struct glue *g; 133 134 if (!__sdidinit) 135 __sinit(); 136 /* 137 * The list must be locked because a FILE may be updated. 138 */ 139 STDIO_THREAD_LOCK(); 140 for (g = &__sglue; g != NULL; g = g->next) { 141 for (fp = g->iobs, n = g->niobs; --n >= 0; fp++) 142 if (fp->_flags == 0) 143 goto found; 144 } 145 STDIO_THREAD_UNLOCK(); /* don't hold lock while malloc()ing. */ 146 if ((g = moreglue(NDYNAMIC)) == NULL) 147 return (NULL); 148 STDIO_THREAD_LOCK(); /* reacquire the lock */ 149 SET_GLUE_PTR(lastglue->next, g); /* atomically append glue to list */ 150 lastglue = g; /* not atomic; only accessed when locked */ 151 fp = g->iobs; 152 found: 153 fp->_flags = 1; /* reserve this slot; caller sets real flags */ 154 STDIO_THREAD_UNLOCK(); 155 fp->_p = NULL; /* no current pointer */ 156 fp->_w = 0; /* nothing to read or write */ 157 fp->_r = 0; 158 fp->_bf._base = NULL; /* no buffer */ 159 fp->_bf._size = 0; 160 fp->_lbfsize = 0; /* not line buffered */ 161 fp->_file = -1; /* no file */ 162 /* fp->_cookie = <any>; */ /* caller sets cookie, _read/_write etc */ 163 fp->_ub._base = NULL; /* no ungetc buffer */ 164 fp->_ub._size = 0; 165 fp->_lb._base = NULL; /* no line buffer */ 166 fp->_lb._size = 0; 167 /* fp->_fl_mutex = NULL; */ /* once set always set (reused) */ 168 fp->_orientation = 0; 169 memset(&fp->_mbstate, 0, sizeof(mbstate_t)); 170 fp->_flags2 = 0; 171 return (fp); 172 } 173 174 /* 175 * XXX. Force immediate allocation of internal memory. Not used by stdio, 176 * but documented historically for certain applications. Bad applications. 177 */ 178 __warn_references(f_prealloc, 179 "warning: this program uses f_prealloc(), which is not recommended."); 180 void f_prealloc(void); 181 182 void 183 f_prealloc(void) 184 { 185 struct glue *g; 186 int n; 187 188 n = getdtablesize() - FOPEN_MAX + 20; /* 20 for slop. */ 189 /* 190 * It should be safe to walk the list without locking it; 191 * new nodes are only added to the end and none are ever 192 * removed. 193 */ 194 for (g = &__sglue; (n -= g->niobs) > 0 && g->next; g = g->next) 195 /* void */; 196 if ((n > 0) && ((g = moreglue(n)) != NULL)) { 197 STDIO_THREAD_LOCK(); 198 SET_GLUE_PTR(lastglue->next, g); 199 lastglue = g; 200 STDIO_THREAD_UNLOCK(); 201 } 202 } 203 204 /* 205 * exit() calls _cleanup() through *__cleanup, set whenever we 206 * open or buffer a file. This chicanery is done so that programs 207 * that do not use stdio need not link it all in. 208 * 209 * The name `_cleanup' is, alas, fairly well known outside stdio. 210 */ 211 void 212 _cleanup(void) 213 { 214 /* (void) _fwalk(fclose); */ 215 (void) _fwalk(__sflush); /* `cheating' */ 216 } 217 218 /* 219 * __sinit() is called whenever stdio's internal variables must be set up. 220 */ 221 void 222 __sinit(void) 223 { 224 225 /* Make sure we clean up on exit. */ 226 __cleanup = _cleanup; /* conservative */ 227 __sdidinit = 1; 228 } 229