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
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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37 #if defined(LIBC_SCCS) && !defined(lint)
38 static char sccsid
[] = "@(#)findfp.c 8.2 (Berkeley) 1/4/94";
39 #endif /* LIBC_SCCS and not lint */
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD: src/lib/libc/stdio/findfp.c,v 1.29 2004/05/22 15:19:41 tjr Exp $");
43 #include <sys/param.h>
44 #include <machine/atomic.h>
53 #include "libc_private.h"
59 #define NDYNAMIC 10 /* add ten more whenever necessary */
61 #define std(flags, file) \
62 {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 #define __sFXInit {0, PTHREAD_MUTEX_INITIALIZER}
67 /* the usual - (stdin + stdout + stderr) */
68 static FILE usual
[FOPEN_MAX
- 3];
69 static struct __sFILEX usual_extra
[FOPEN_MAX
- 3];
70 static struct glue uglue
= { NULL
, FOPEN_MAX
- 3, usual
};
72 static struct __sFILEX __sFX
[3] = {__sFXInit
, __sFXInit
, __sFXInit
};
75 * We can't make this 'static' until 6.0-current due to binary
76 * compatibility concerns. This also means we cannot change the
77 * sizeof(FILE) until that time either and must continue to use the
78 * __sFILEX stuff to add to FILE.
81 std(__SRD
, STDIN_FILENO
),
82 std(__SWR
, STDOUT_FILENO
),
83 std(__SWR
|__SNBF
, STDERR_FILENO
)
87 * The following kludge is done to ensure enough binary compatibility
88 * with future versions of libc. Or rather it allows us to work with
89 * libraries that have been built with a newer libc that defines these
90 * symbols and expects libc to provide them. We only have need to support
91 * i386 and alpha because they are the only "old" systems we have deployed.
93 FILE *__stdinp
= &__sF
[0];
94 FILE *__stdoutp
= &__sF
[1];
95 FILE *__stderrp
= &__sF
[2];
97 struct glue __sglue
= { &uglue
, 3, __sF
};
98 static struct glue
*lastglue
= &uglue
;
100 static struct glue
* moreglue(int);
102 static spinlock_t thread_lock
= _SPINLOCK_INITIALIZER
;
103 #define THREAD_LOCK() if (__isthreaded) _SPINLOCK(&thread_lock)
104 #define THREAD_UNLOCK() if (__isthreaded) _SPINUNLOCK(&thread_lock)
107 #define SET_GLUE_PTR(ptr, val) atomic_set_rel_ptr(&(ptr), (uintptr_t)(val))
109 #define SET_GLUE_PTR(ptr, val) ptr = val
118 static struct __sFILEX emptyx
= __sFXInit
;
122 g
= (struct glue
*)malloc(sizeof(*g
) + ALIGNBYTES
+ n
* sizeof(FILE) +
123 n
* sizeof(struct __sFILEX
));
126 p
= (FILE *)ALIGN(g
+ 1);
127 fx
= (struct __sFILEX
*)&p
[n
];
141 * Find a free FILE for fopen et al.
153 * The list must be locked because a FILE may be updated.
156 for (g
= &__sglue
; g
!= NULL
; g
= g
->next
) {
157 for (fp
= g
->iobs
, n
= g
->niobs
; --n
>= 0; fp
++)
161 THREAD_UNLOCK(); /* don't hold lock while malloc()ing. */
162 if ((g
= moreglue(NDYNAMIC
)) == NULL
)
164 THREAD_LOCK(); /* reacquire the lock */
165 SET_GLUE_PTR(lastglue
->next
, g
); /* atomically append glue to list */
166 lastglue
= g
; /* not atomic; only accessed when locked */
169 fp
->_flags
= 1; /* reserve this slot; caller sets real flags */
171 fp
->_p
= NULL
; /* no current pointer */
172 fp
->_w
= 0; /* nothing to read or write */
174 fp
->_bf
._base
= NULL
; /* no buffer */
176 fp
->_lbfsize
= 0; /* not line buffered */
177 fp
->_file
= -1; /* no file */
178 /* fp->_cookie = <any>; */ /* caller sets cookie, _read/_write etc */
179 fp
->_ub
._base
= NULL
; /* no ungetc buffer */
181 fp
->_lb
._base
= NULL
; /* no line buffer */
183 /* fp->_lock = NULL; */ /* once set always set (reused) */
184 fp
->_extra
->fl_mutex
= (pthread_mutex_t
)PTHREAD_MUTEX_INITIALIZER
;
185 fp
->_extra
->orientation
= 0;
186 memset(&fp
->_extra
->mbstate
, 0, sizeof(mbstate_t));
191 * XXX. Force immediate allocation of internal memory. Not used by stdio,
192 * but documented historically for certain applications. Bad applications.
194 __warn_references(f_prealloc
,
195 "warning: this program uses f_prealloc(), which is not recommended.");
203 n
= getdtablesize() - FOPEN_MAX
+ 20; /* 20 for slop. */
205 * It should be safe to walk the list without locking it;
206 * new nodes are only added to the end and none are ever
209 for (g
= &__sglue
; (n
-= g
->niobs
) > 0 && g
->next
; g
= g
->next
)
211 if ((n
> 0) && ((g
= moreglue(n
)) != NULL
)) {
213 SET_GLUE_PTR(lastglue
->next
, g
);
220 * exit() calls _cleanup() through *__cleanup, set whenever we
221 * open or buffer a file. This chicanery is done so that programs
222 * that do not use stdio need not link it all in.
224 * The name `_cleanup' is, alas, fairly well known outside stdio.
229 /* (void) _fwalk(fclose); */
230 (void) _fwalk(__sflush
); /* `cheating' */
234 * __sinit() is called whenever stdio's internal variables must be set up.
242 if (__sdidinit
== 0) {
243 /* Set _extra for the usual suspects. */
244 for (i
= 0; i
< FOPEN_MAX
- 3; i
++)
245 usual
[i
]._extra
= &usual_extra
[i
];
247 /* Make sure we clean up on exit. */
248 __cleanup
= _cleanup
; /* conservative */