2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
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.
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
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("$FreeBSD$");
39 #include <sys/param.h>
40 #include <machine/atomic.h>
48 #include "libc_private.h"
54 #define NDYNAMIC 10 /* add ten more whenever necessary */
56 #define std(flags, file) { \
59 ._cookie = __sF + (file), \
64 ._fl_mutex = PTHREAD_MUTEX_INITIALIZER, \
66 /* the usual - (stdin + stdout + stderr) */
67 static FILE usual[FOPEN_MAX - 3];
68 static struct glue uglue = { NULL, FOPEN_MAX - 3, usual };
70 static FILE __sF[3] = {
71 std(__SRD, STDIN_FILENO),
72 std(__SWR, STDOUT_FILENO),
73 std(__SWR|__SNBF, STDERR_FILENO)
76 FILE *__stdinp = &__sF[0];
77 FILE *__stdoutp = &__sF[1];
78 FILE *__stderrp = &__sF[2];
80 struct glue __sglue = { &uglue, 3, __sF };
81 static struct glue *lastglue = &uglue;
83 static struct glue * moreglue(int);
85 spinlock_t __stdio_thread_lock = _SPINLOCK_INITIALIZER;
88 #define SET_GLUE_PTR(ptr, val) atomic_set_rel_ptr(&(ptr), (uintptr_t)(val))
90 #define SET_GLUE_PTR(ptr, val) ptr = val
97 static FILE empty = { ._fl_mutex = PTHREAD_MUTEX_INITIALIZER };
100 g = (struct glue *)malloc(sizeof(*g) + ALIGNBYTES + n * sizeof(FILE));
103 p = (FILE *)ALIGN(g + 1);
113 * Find a free FILE for fopen et al.
125 * The list must be locked because a FILE may be updated.
128 for (g = &__sglue; g != NULL; g = g->next) {
129 for (fp = g->iobs, n = g->niobs; --n >= 0; fp++)
133 STDIO_THREAD_UNLOCK(); /* don't hold lock while malloc()ing. */
134 if ((g = moreglue(NDYNAMIC)) == NULL)
136 STDIO_THREAD_LOCK(); /* reacquire the lock */
137 SET_GLUE_PTR(lastglue->next, g); /* atomically append glue to list */
138 lastglue = g; /* not atomic; only accessed when locked */
141 fp->_flags = 1; /* reserve this slot; caller sets real flags */
142 STDIO_THREAD_UNLOCK();
143 fp->_p = NULL; /* no current pointer */
144 fp->_w = 0; /* nothing to read or write */
146 fp->_bf._base = NULL; /* no buffer */
148 fp->_lbfsize = 0; /* not line buffered */
149 fp->_file = -1; /* no file */
150 /* fp->_cookie = <any>; */ /* caller sets cookie, _read/_write etc */
151 fp->_ub._base = NULL; /* no ungetc buffer */
153 fp->_lb._base = NULL; /* no line buffer */
155 /* fp->_fl_mutex = NULL; */ /* once set always set (reused) */
156 fp->_orientation = 0;
157 memset(&fp->_mbstate, 0, sizeof(mbstate_t));
162 * XXX. Force immediate allocation of internal memory. Not used by stdio,
163 * but documented historically for certain applications. Bad applications.
165 __warn_references(f_prealloc,
166 "warning: this program uses f_prealloc(), which is not recommended.");
174 n = getdtablesize() - FOPEN_MAX + 20; /* 20 for slop. */
176 * It should be safe to walk the list without locking it;
177 * new nodes are only added to the end and none are ever
180 for (g = &__sglue; (n -= g->niobs) > 0 && g->next; g = g->next)
182 if ((n > 0) && ((g = moreglue(n)) != NULL)) {
184 SET_GLUE_PTR(lastglue->next, g);
186 STDIO_THREAD_UNLOCK();
191 * exit() calls _cleanup() through *__cleanup, set whenever we
192 * open or buffer a file. This chicanery is done so that programs
193 * that do not use stdio need not link it all in.
195 * The name `_cleanup' is, alas, fairly well known outside stdio.
200 /* (void) _fwalk(fclose); */
201 (void) _fwalk(__sflush); /* `cheating' */
205 * __sinit() is called whenever stdio's internal variables must be set up.
211 /* Make sure we clean up on exit. */
212 __cleanup = _cleanup; /* conservative */