findfp.c revision 1.19
1 /* $NetBSD: findfp.c,v 1.19 2003/07/18 21:46:41 nathanw 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. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #include <sys/cdefs.h> 40 #if defined(LIBC_SCCS) && !defined(lint) 41 #if 0 42 static char sccsid[] = "@(#)findfp.c 8.2 (Berkeley) 1/4/94"; 43 #else 44 __RCSID("$NetBSD: findfp.c,v 1.19 2003/07/18 21:46:41 nathanw Exp $"); 45 #endif 46 #endif /* LIBC_SCCS and not lint */ 47 48 #include "namespace.h" 49 #include <sys/param.h> 50 #include <unistd.h> 51 #include <stdio.h> 52 #include <errno.h> 53 #include <stdlib.h> 54 #include <string.h> 55 #include "reentrant.h" 56 #include "local.h" 57 #include "glue.h" 58 59 int __sdidinit; 60 61 #define NDYNAMIC 10 /* add ten more whenever necessary */ 62 63 #define std(flags, file) \ 64 /* p r w flags file bf lfbsize cookie close */ \ 65 { NULL, 0, 0, flags, file, { NULL, 0 }, 0, __sF + file, __sclose, \ 66 /* read seek write ext up */ \ 67 __sread, __sseek, __swrite, { (void *)(__sFext + file), 0 }, NULL, \ 68 /* ur ubuf, nbuf lb blksize offset */ \ 69 0, { '\0', '\0', '\0' }, { '\0' }, { NULL, 0 }, 0, (fpos_t)0 } 70 71 /* the usual - (stdin + stdout + stderr) */ 72 static FILE usual[FOPEN_MAX - 3]; 73 static struct __sfileext usualext[FOPEN_MAX - 3]; 74 static struct glue uglue = { 0, FOPEN_MAX - 3, usual }; 75 76 #ifdef _REENTRANT 77 #define STDEXT { {0}, {{{0}}}, MUTEX_INITIALIZER, COND_INITIALIZER, NULL, 0, 0} 78 struct __sfileext __sFext[3] = { STDEXT, 79 STDEXT, 80 STDEXT}; 81 #else 82 struct __sfileext __sFext[3]; 83 #endif 84 85 FILE __sF[3] = { 86 std(__SRD, STDIN_FILENO), /* stdin */ 87 std(__SWR, STDOUT_FILENO), /* stdout */ 88 std(__SWR|__SNBF, STDERR_FILENO) /* stderr */ 89 }; 90 struct glue __sglue = { &uglue, 3, __sF }; 91 92 static struct glue *moreglue __P((int)); 93 void f_prealloc __P((void)); 94 95 #ifdef _REENTRANT 96 rwlock_t __sfp_lock = RWLOCK_INITIALIZER; 97 #endif 98 99 static struct glue * 100 moreglue(n) 101 int n; 102 { 103 struct glue *g; 104 FILE *p; 105 struct __sfileext *pext; 106 static FILE empty; 107 108 g = (struct glue *)malloc(sizeof(*g) + ALIGNBYTES + n * sizeof(FILE) 109 + n * sizeof(struct __sfileext)); 110 if (g == NULL) 111 return (NULL); 112 p = (FILE *)ALIGN((u_long)(g + 1)); 113 g->next = NULL; 114 g->niobs = n; 115 g->iobs = p; 116 pext = (void *)(p + n); 117 while (--n >= 0) { 118 *p = empty; 119 _FILEEXT_SETUP(p, pext); 120 p++; 121 pext++; 122 } 123 return (g); 124 } 125 126 /* 127 * Find a free FILE for fopen et al. 128 */ 129 FILE * 130 __sfp() 131 { 132 FILE *fp; 133 int n; 134 struct glue *g; 135 136 if (!__sdidinit) 137 __sinit(); 138 139 rwlock_wrlock(&__sfp_lock); 140 for (g = &__sglue;; g = g->next) { 141 for (fp = g->iobs, n = g->niobs; --n >= 0; fp++) 142 if (fp->_flags == 0) 143 goto found; 144 if (g->next == NULL && (g->next = moreglue(NDYNAMIC)) == NULL) 145 break; 146 } 147 rwlock_unlock(&__sfp_lock); 148 return (NULL); 149 found: 150 fp->_flags = 1; /* reserve this slot; caller sets real flags */ 151 fp->_p = NULL; /* no current pointer */ 152 fp->_w = 0; /* nothing to read or write */ 153 fp->_r = 0; 154 fp->_bf._base = NULL; /* no buffer */ 155 fp->_bf._size = 0; 156 fp->_lbfsize = 0; /* not line buffered */ 157 fp->_file = -1; /* no file */ 158 /* fp->_cookie = <any>; */ /* caller sets cookie, _read/_write etc */ 159 _UB(fp)._base = NULL; /* no ungetc buffer */ 160 _UB(fp)._size = 0; 161 fp->_lb._base = NULL; /* no line buffer */ 162 fp->_lb._size = 0; 163 memset(WCIO_GET(fp), 0, sizeof(struct wchar_io_data)); 164 rwlock_unlock(&__sfp_lock); 165 return (fp); 166 } 167 168 /* 169 * XXX. Force immediate allocation of internal memory. Not used by stdio, 170 * but documented historically for certain applications. Bad applications. 171 */ 172 void 173 f_prealloc() 174 { 175 struct glue *g; 176 int n; 177 178 n = (int)sysconf(_SC_OPEN_MAX) - FOPEN_MAX + 20; /* 20 for slop. */ 179 for (g = &__sglue; (n -= g->niobs) > 0 && g->next; g = g->next) 180 /* void */; 181 if (n > 0) 182 g->next = moreglue(n); 183 } 184 185 /* 186 * exit() calls _cleanup() through *__cleanup, set whenever we 187 * open or buffer a file. This chicanery is done so that programs 188 * that do not use stdio need not link it all in. 189 * 190 * The name `_cleanup' is, alas, fairly well known outside stdio. 191 */ 192 void 193 _cleanup() 194 { 195 /* (void) _fwalk(fclose); */ 196 (void) fflush(NULL); /* `cheating' */ 197 } 198 199 /* 200 * __sinit() is called whenever stdio's internal variables must be set up. 201 */ 202 void 203 __sinit() 204 { 205 int i; 206 207 for (i = 0; i < FOPEN_MAX - 3; i++) 208 _FILEEXT_SETUP(&usual[i], &usualext[i]); 209 210 /* make sure we clean up on exit */ 211 __cleanup = _cleanup; /* conservative */ 212 __sdidinit = 1; 213 } 214
Indexes created Mon Sep 22 10:09:38 GMT 2025