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
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9 * modification, are permitted provided that the following conditions
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12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
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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
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24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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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("$FreeBSD$");
43 #include <sys/param.h>
44 #include <machine/atomic.h>
52 #include "libc_private.h"
58 #define NDYNAMIC 10 /* add ten more whenever necessary */
60 #define std(flags, file) \
61 {0,0,0,flags,file,{0},0,__sF+file,__sclose,__sread,__sseek,__swrite, \
63 /* p r w flags file _bf z cookie close read seek write */
65 /* the usual - (stdin + stdout + stderr) */
66 static FILE usual[FOPEN_MAX - 3];
67 static struct __sFILEX usual_extra[FOPEN_MAX - 3];
68 static struct glue uglue = { NULL, FOPEN_MAX - 3, usual };
70 static struct __sFILEX __sFX[3];
73 * We can't make this 'static' until 6.0-current due to binary
74 * compatibility concerns. This also means we cannot change the
75 * sizeof(FILE) until that time either and must continue to use the
76 * __sFILEX stuff to add to FILE.
79 std(__SRD, STDIN_FILENO),
80 std(__SWR, STDOUT_FILENO),
81 std(__SWR|__SNBF, STDERR_FILENO)
85 * The following kludge is done to ensure enough binary compatibility
86 * with future versions of libc. Or rather it allows us to work with
87 * libraries that have been built with a newer libc that defines these
88 * symbols and expects libc to provide them. We only have need to support
89 * i386 and alpha because they are the only "old" systems we have deployed.
91 FILE *__stdinp = &__sF[0];
92 FILE *__stdoutp = &__sF[1];
93 FILE *__stderrp = &__sF[2];
95 struct glue __sglue = { &uglue, 3, __sF };
96 static struct glue *lastglue = &uglue;
98 static struct glue * moreglue(int);
100 static spinlock_t thread_lock = _SPINLOCK_INITIALIZER;
101 #define THREAD_LOCK() if (__isthreaded) _SPINLOCK(&thread_lock)
102 #define THREAD_UNLOCK() if (__isthreaded) _SPINUNLOCK(&thread_lock)
105 #define SET_GLUE_PTR(ptr, val) atomic_set_rel_ptr(&(ptr), (uintptr_t)(val))
107 #define SET_GLUE_PTR(ptr, val) ptr = val
116 static struct __sFILEX emptyx;
120 g = (struct glue *)malloc(sizeof(*g) + ALIGNBYTES + n * sizeof(FILE) +
121 n * sizeof(struct __sFILEX));
124 p = (FILE *)ALIGN(g + 1);
125 fx = (struct __sFILEX *)&p[n];
139 * Find a free FILE for fopen et al.
151 * The list must be locked because a FILE may be updated.
154 for (g = &__sglue; g != NULL; g = g->next) {
155 for (fp = g->iobs, n = g->niobs; --n >= 0; fp++)
159 THREAD_UNLOCK(); /* don't hold lock while malloc()ing. */
160 if ((g = moreglue(NDYNAMIC)) == NULL)
162 THREAD_LOCK(); /* reacquire the lock */
163 SET_GLUE_PTR(lastglue->next, g); /* atomically append glue to list */
164 lastglue = g; /* not atomic; only accessed when locked */
167 fp->_flags = 1; /* reserve this slot; caller sets real flags */
169 fp->_p = NULL; /* no current pointer */
170 fp->_w = 0; /* nothing to read or write */
172 fp->_bf._base = NULL; /* no buffer */
174 fp->_lbfsize = 0; /* not line buffered */
175 fp->_file = -1; /* no file */
176 /* fp->_cookie = <any>; */ /* caller sets cookie, _read/_write etc */
177 fp->_ub._base = NULL; /* no ungetc buffer */
179 fp->_lb._base = NULL; /* no line buffer */
181 /* fp->_lock = NULL; */ /* once set always set (reused) */
182 fp->_extra->orientation = 0;
183 memset(&fp->_extra->mbstate, 0, sizeof(mbstate_t));
188 * XXX. Force immediate allocation of internal memory. Not used by stdio,
189 * but documented historically for certain applications. Bad applications.
191 __warn_references(f_prealloc,
192 "warning: this program uses f_prealloc(), which is not recommended.");
200 n = getdtablesize() - FOPEN_MAX + 20; /* 20 for slop. */
202 * It should be safe to walk the list without locking it;
203 * new nodes are only added to the end and none are ever
206 for (g = &__sglue; (n -= g->niobs) > 0 && g->next; g = g->next)
208 if ((n > 0) && ((g = moreglue(n)) != NULL)) {
210 SET_GLUE_PTR(lastglue->next, g);
217 * exit() calls _cleanup() through *__cleanup, set whenever we
218 * open or buffer a file. This chicanery is done so that programs
219 * that do not use stdio need not link it all in.
221 * The name `_cleanup' is, alas, fairly well known outside stdio.
226 /* (void) _fwalk(fclose); */
227 (void) _fwalk(__sflush); /* `cheating' */
231 * __sinit() is called whenever stdio's internal variables must be set up.
239 if (__sdidinit == 0) {
240 /* Set _extra for the usual suspects. */
241 for (i = 0; i < FOPEN_MAX - 3; i++)
242 usual[i]._extra = &usual_extra[i];
244 /* Make sure we clean up on exit. */
245 __cleanup = _cleanup; /* conservative */