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. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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37 #if defined(LIBC_SCCS) && !defined(lint)
39 static char sccsid[] = "@(#)findfp.c 8.2 (Berkeley) 1/4/94";
41 static const char rcsid[] =
42 "$FreeBSD: src/lib/libc/stdio/findfp.c,v 1.7.2.3 2001/08/17 02:56:31 peter Exp $";
43 #endif /* LIBC_SCCS and not lint */
45 #include <sys/param.h>
52 #include <libc_private.h>
60 #define NDYNAMIC 10 /* add ten more whenever necessary */
62 #define std(flags, file) \
63 {0,0,0,flags,file,{0},0,__sF+file,__sclose,__sread,__sseek,__swrite}
64 /* p r w flags file _bf z cookie close read seek write */
66 /* the usual - (stdin + stdout + stderr) */
67 static FILE usual[FOPEN_MAX - 3];
68 static struct glue uglue = { 0, FOPEN_MAX - 3, usual };
71 std(__SRD, STDIN_FILENO), /* stdin */
72 std(__SWR, STDOUT_FILENO), /* stdout */
73 std(__SWR|__SNBF, STDERR_FILENO) /* stderr */
75 struct glue __sglue = { &uglue, 3, __sF };
78 * The following kludge is done to ensure enough binary compatibility
79 * with future versions of libc. Or rather it allows us to work with
80 * libraries that have been built with a newer libc that defines these
81 * symbols and expects libc to provide them. We only have need to support
82 * i386 and alpha because they are the only "old" systems we have deployed.
84 FILE *__stdinp = &__sF[0];
85 FILE *__stdoutp = &__sF[1];
86 FILE *__stderrp = &__sF[2];
88 static struct glue * moreglue __P((int));
90 static spinlock_t thread_lock = _SPINLOCK_INITIALIZER;
91 #define THREAD_LOCK() if (__isthreaded) _SPINLOCK(&thread_lock)
92 #define THREAD_UNLOCK() if (__isthreaded) _SPINUNLOCK(&thread_lock)
98 register struct glue *g;
102 g = (struct glue *)malloc(sizeof(*g) + ALIGNBYTES + n * sizeof(FILE));
105 p = (FILE *)ALIGN(g + 1);
115 * Find a free FILE for fopen et al.
122 register struct glue *g;
127 for (g = &__sglue;; g = g->next) {
128 for (fp = g->iobs, n = g->niobs; --n >= 0; fp++)
131 if (g->next == NULL && (g->next = moreglue(NDYNAMIC)) == NULL)
137 fp->_flags = 1; /* reserve this slot; caller sets real flags */
139 fp->_p = NULL; /* no current pointer */
140 fp->_w = 0; /* nothing to read or write */
142 fp->_bf._base = NULL; /* no buffer */
144 fp->_lbfsize = 0; /* not line buffered */
145 fp->_file = -1; /* no file */
146 /* fp->_cookie = <any>; */ /* caller sets cookie, _read/_write etc */
147 fp->_ub._base = NULL; /* no ungetc buffer */
149 fp->_lb._base = NULL; /* no line buffer */
155 * XXX. Force immediate allocation of internal memory. Not used by stdio,
156 * but documented historically for certain applications. Bad applications.
158 __warn_references(f_prealloc,
159 "warning: this program uses f_prealloc(), which is not recommended.");
164 register struct glue *g;
167 n = getdtablesize() - FOPEN_MAX + 20; /* 20 for slop. */
168 for (g = &__sglue; (n -= g->niobs) > 0 && g->next; g = g->next)
171 g->next = moreglue(n);
175 * exit() calls _cleanup() through *__cleanup, set whenever we
176 * open or buffer a file. This chicanery is done so that programs
177 * that do not use stdio need not link it all in.
179 * The name `_cleanup' is, alas, fairly well known outside stdio.
184 /* (void) _fwalk(fclose); */
185 (void) _fwalk(__sflush); /* `cheating' */
189 * __sinit() is called whenever stdio's internal variables must be set up.
194 /* make sure we clean up on exit */
195 __cleanup = _cleanup; /* conservative */