2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (c) 1990, 1993
5 * The Regents of the University of California. All rights reserved.
7 * This code is derived from software contributed to Berkeley by
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
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.
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
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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
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31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 #if defined(LIBC_SCCS) && !defined(lint)
36 static char sccsid[] = "@(#)findfp.c 8.2 (Berkeley) 1/4/94";
37 #endif /* LIBC_SCCS and not lint */
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
41 #include <sys/param.h>
42 #include <machine/atomic.h>
51 #include "libc_private.h"
57 #define NDYNAMIC 10 /* add ten more whenever necessary */
59 #define std(flags, file) { \
62 ._cookie = __sF + (file), \
67 ._fl_mutex = PTHREAD_MUTEX_INITIALIZER, \
69 /* the usual - (stdin + stdout + stderr) */
70 static FILE usual[FOPEN_MAX - 3];
71 static struct glue uglue = { NULL, FOPEN_MAX - 3, usual };
73 static FILE __sF[3] = {
74 std(__SRD, STDIN_FILENO),
75 std(__SWR, STDOUT_FILENO),
76 std(__SWR|__SNBF, STDERR_FILENO)
79 FILE *__stdinp = &__sF[0];
80 FILE *__stdoutp = &__sF[1];
81 FILE *__stderrp = &__sF[2];
83 struct glue __sglue = { &uglue, 3, __sF };
84 static struct glue *lastglue = &uglue;
86 static struct glue * moreglue(int);
88 spinlock_t __stdio_thread_lock = _SPINLOCK_INITIALIZER;
91 #define SET_GLUE_PTR(ptr, val) atomic_set_rel_ptr(&(ptr), (uintptr_t)(val))
93 #define SET_GLUE_PTR(ptr, val) ptr = val
100 static FILE empty = { ._fl_mutex = PTHREAD_MUTEX_INITIALIZER };
104 align = __alignof__(FILE);
105 g = (struct glue *)malloc(sizeof(*g) + align + n * sizeof(FILE));
108 p = (FILE *)roundup((uintptr_t)(g + 1), align);
118 * Find a free FILE for fopen et al.
130 * The list must be locked because a FILE may be updated.
133 for (g = &__sglue; g != NULL; g = g->next) {
134 for (fp = g->iobs, n = g->niobs; --n >= 0; fp++)
138 STDIO_THREAD_UNLOCK(); /* don't hold lock while malloc()ing. */
139 if ((g = moreglue(NDYNAMIC)) == NULL)
141 STDIO_THREAD_LOCK(); /* reacquire the lock */
142 SET_GLUE_PTR(lastglue->next, g); /* atomically append glue to list */
143 lastglue = g; /* not atomic; only accessed when locked */
146 fp->_flags = 1; /* reserve this slot; caller sets real flags */
147 STDIO_THREAD_UNLOCK();
148 fp->_p = NULL; /* no current pointer */
149 fp->_w = 0; /* nothing to read or write */
151 fp->_bf._base = NULL; /* no buffer */
153 fp->_lbfsize = 0; /* not line buffered */
154 fp->_file = -1; /* no file */
155 /* fp->_cookie = <any>; */ /* caller sets cookie, _read/_write etc */
156 fp->_ub._base = NULL; /* no ungetc buffer */
158 fp->_lb._base = NULL; /* no line buffer */
160 /* fp->_fl_mutex = NULL; */ /* once set always set (reused) */
161 fp->_orientation = 0;
162 memset(&fp->_mbstate, 0, sizeof(mbstate_t));
168 * XXX. Force immediate allocation of internal memory. Not used by stdio,
169 * but documented historically for certain applications. Bad applications.
171 __warn_references(f_prealloc,
172 "warning: this program uses f_prealloc(), which is not recommended.");
173 void f_prealloc(void);
181 n = getdtablesize() - FOPEN_MAX + 20; /* 20 for slop. */
183 * It should be safe to walk the list without locking it;
184 * new nodes are only added to the end and none are ever
187 for (g = &__sglue; (n -= g->niobs) > 0 && g->next; g = g->next)
189 if ((n > 0) && ((g = moreglue(n)) != NULL)) {
191 SET_GLUE_PTR(lastglue->next, g);
193 STDIO_THREAD_UNLOCK();
198 * exit() calls _cleanup() through *__cleanup, set whenever we
199 * open or buffer a file. This chicanery is done so that programs
200 * that do not use stdio need not link it all in.
202 * The name `_cleanup' is, alas, fairly well known outside stdio.
207 /* (void) _fwalk(fclose); */
208 (void) _fwalk(__sflush); /* `cheating' */
212 * __sinit() is called whenever stdio's internal variables must be set up.
218 /* Make sure we clean up on exit. */
219 __cleanup = _cleanup; /* conservative */