1 /* $NetBSD: findfp.c,v 1.20 2003/08/07 16:43:23 agc Exp $ */ 2 3 /*- 4 * Copyright (c) 1990, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Chris Torek. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #include <sys/cdefs.h> 36 #if defined(LIBC_SCCS) && !defined(lint) 37 #if 0 38 static char sccsid[] = "@(#)findfp.c 8.2 (Berkeley) 1/4/94"; 39 #else 40 __RCSID("$NetBSD: findfp.c,v 1.20 2003/08/07 16:43:23 agc Exp $"); 41 #endif 42 #endif /* LIBC_SCCS and not lint */ 43 44 #include "namespace.h" 45 #include <sys/param.h> 46 #include <unistd.h> 47 #include <stdio.h> 48 #include <errno.h> 49 #include <stdlib.h> 50 #include <string.h> 51 #include "reentrant.h" 52 #include "local.h" 53 #include "glue.h" 54 55 int __sdidinit; 56 57 #define NDYNAMIC 10 /* add ten more whenever necessary */ 58 59 #define std(flags, file) \ 60 /* p r w flags file bf lfbsize cookie close */ \ 61 { NULL, 0, 0, flags, file, { NULL, 0 }, 0, __sF + file, __sclose, \ 62 /* read seek write ext up */ \ 63 __sread, __sseek, __swrite, { (void *)(__sFext + file), 0 }, NULL, \ 64 /* ur ubuf, nbuf lb blksize offset */ \ 65 0, { '\0', '\0', '\0' }, { '\0' }, { NULL, 0 }, 0, (fpos_t)0 } 66 67 /* the usual - (stdin + stdout + stderr) */ 68 static FILE usual[FOPEN_MAX - 3]; 69 static struct __sfileext usualext[FOPEN_MAX - 3]; 70 static struct glue uglue = { 0, FOPEN_MAX - 3, usual }; 71 72 #ifdef _REENTRANT 73 #define STDEXT { {0}, {{{0}}}, MUTEX_INITIALIZER, COND_INITIALIZER, NULL, 0, 0} 74 struct __sfileext __sFext[3] = { STDEXT, 75 STDEXT, 76 STDEXT}; 77 #else 78 struct __sfileext __sFext[3]; 79 #endif 80 81 FILE __sF[3] = { 82 std(__SRD, STDIN_FILENO), /* stdin */ 83 std(__SWR, STDOUT_FILENO), /* stdout */ 84 std(__SWR|__SNBF, STDERR_FILENO) /* stderr */ 85 }; 86 struct glue __sglue = { &uglue, 3, __sF }; 87 88 static struct glue *moreglue __P((int)); 89 void f_prealloc __P((void)); 90 91 #ifdef _REENTRANT 92 rwlock_t __sfp_lock = RWLOCK_INITIALIZER; 93 #endif 94 95 static struct glue * 96 moreglue(n) 97 int n; 98 { 99 struct glue *g; 100 FILE *p; 101 struct __sfileext *pext; 102 static FILE empty; 103 104 g = (struct glue *)malloc(sizeof(*g) + ALIGNBYTES + n * sizeof(FILE) 105 + n * sizeof(struct __sfileext)); 106 if (g == NULL) 107 return (NULL); 108 p = (FILE *)ALIGN((u_long)(g + 1)); 109 g->next = NULL; 110 g->niobs = n; 111 g->iobs = p; 112 pext = (void *)(p + n); 113 while (--n >= 0) { 114 *p = empty; 115 _FILEEXT_SETUP(p, pext); 116 p++; 117 pext++; 118 } 119 return (g); 120 } 121 122 /* 123 * Find a free FILE for fopen et al. 124 */ 125 FILE * 126 __sfp() 127 { 128 FILE *fp; 129 int n; 130 struct glue *g; 131 132 if (!__sdidinit) 133 __sinit(); 134 135 rwlock_wrlock(&__sfp_lock); 136 for (g = &__sglue;; g = g->next) { 137 for (fp = g->iobs, n = g->niobs; --n >= 0; fp++) 138 if (fp->_flags == 0) 139 goto found; 140 if (g->next == NULL && (g->next = moreglue(NDYNAMIC)) == NULL) 141 break; 142 } 143 rwlock_unlock(&__sfp_lock); 144 return (NULL); 145 found: 146 fp->_flags = 1; /* reserve this slot; caller sets real flags */ 147 fp->_p = NULL; /* no current pointer */ 148 fp->_w = 0; /* nothing to read or write */ 149 fp->_r = 0; 150 fp->_bf._base = NULL; /* no buffer */ 151 fp->_bf._size = 0; 152 fp->_lbfsize = 0; /* not line buffered */ 153 fp->_file = -1; /* no file */ 154 /* fp->_cookie = <any>; */ /* caller sets cookie, _read/_write etc */ 155 _UB(fp)._base = NULL; /* no ungetc buffer */ 156 _UB(fp)._size = 0; 157 fp->_lb._base = NULL; /* no line buffer */ 158 fp->_lb._size = 0; 159 memset(WCIO_GET(fp), 0, sizeof(struct wchar_io_data)); 160 rwlock_unlock(&__sfp_lock); 161 return (fp); 162 } 163 164 /* 165 * XXX. Force immediate allocation of internal memory. Not used by stdio, 166 * but documented historically for certain applications. Bad applications. 167 */ 168 void 169 f_prealloc() 170 { 171 struct glue *g; 172 int n; 173 174 n = (int)sysconf(_SC_OPEN_MAX) - FOPEN_MAX + 20; /* 20 for slop. */ 175 for (g = &__sglue; (n -= g->niobs) > 0 && g->next; g = g->next) 176 /* void */; 177 if (n > 0) 178 g->next = moreglue(n); 179 } 180 181 /* 182 * exit() calls _cleanup() through *__cleanup, set whenever we 183 * open or buffer a file. This chicanery is done so that programs 184 * that do not use stdio need not link it all in. 185 * 186 * The name `_cleanup' is, alas, fairly well known outside stdio. 187 */ 188 void 189 _cleanup() 190 { 191 /* (void) _fwalk(fclose); */ 192 (void) fflush(NULL); /* `cheating' */ 193 } 194 195 /* 196 * __sinit() is called whenever stdio's internal variables must be set up. 197 */ 198 void 199 __sinit() 200 { 201 int i; 202 203 for (i = 0; i < FOPEN_MAX - 3; i++) 204 _FILEEXT_SETUP(&usual[i], &usualext[i]); 205 206 /* make sure we clean up on exit */ 207 __cleanup = _cleanup; /* conservative */ 208 __sdidinit = 1; 209 } 210