]> git.saurik.com Git - apple/libc.git/blob - stdio/findfp-fbsd.c
Libc-763.11.tar.gz
[apple/libc.git] / stdio / findfp-fbsd.c
1 /*-
2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Chris Torek.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
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 * 4. 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.
19 *
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
30 * SUCH DAMAGE.
31 */
32
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: src/lib/libc/stdio/findfp.c,v 1.34 2009/12/05 19:31:38 ed Exp $");
38
39 #include <TargetConditionals.h>
40
41 #include <sys/param.h>
42 #include <machine/atomic.h>
43 #include <unistd.h>
44 #include <stdio.h>
45 #include <stdlib.h>
46 #include <string.h>
47 #include <libkern/OSAtomic.h>
48 #include <errno.h>
49
50 #include <pthread.h>
51 #include <spinlock.h>
52
53 #include "libc_private.h"
54 #include "local.h"
55 #include "glue.h"
56
57 int __sdidinit;
58
59 #if !TARGET_OS_EMBEDDED
60 #define NDYNAMIC 10 /* add ten more whenever necessary */
61 #else
62 #define NDYNAMIC 1 /* add one at a time on embedded */
63 #endif
64
65 #define std(flags, file) { \
66 ._flags = (flags), \
67 ._file = (file), \
68 ._cookie = __sF + (file), \
69 ._close = __sclose, \
70 ._read = __sread, \
71 ._seek = __sseek, \
72 ._write = __swrite, \
73 ._extra = __sFX + file, \
74 }
75 #define __sFXInit {.fl_mutex = PTHREAD_MUTEX_INITIALIZER}
76 /* set counted */
77 #define __sFXInit3 {.fl_mutex = PTHREAD_MUTEX_INITIALIZER, .counted = 1}
78
79 static int __scounted; /* streams counted against STREAM_MAX */
80 static int __stream_max;
81
82 #if !TARGET_OS_EMBEDDED
83 /* usual and usual_extra are data pigs. See 7929728. For embedded we should
84 * always allocate dynamically, and probably should for desktop too. */
85 /* the usual - (stdin + stdout + stderr) */
86 static FILE usual[FOPEN_MAX - 3];
87 static struct __sFILEX usual_extra[FOPEN_MAX - 3];
88 static struct glue uglue = { NULL, FOPEN_MAX - 3, usual };
89 #endif /* !TARGET_OS_EMBEDDED */
90
91 static struct __sFILEX __sFX[3] = {__sFXInit3, __sFXInit3, __sFXInit3};
92
93 /*
94 * We can't make this 'static' due to binary compatibility concerns.
95 * This also means we cannot change the sizeof(FILE) and must continue to
96 * use the __sFILEX stuff to add to FILE.
97 */
98 FILE __sF[3] = {
99 std(__SRD, STDIN_FILENO),
100 std(__SWR, STDOUT_FILENO),
101 std(__SWR|__SNBF, STDERR_FILENO)
102 };
103
104 FILE *__stdinp = &__sF[0];
105 FILE *__stdoutp = &__sF[1];
106 FILE *__stderrp = &__sF[2];
107
108 #if !TARGET_OS_EMBEDDED
109 struct glue __sglue = { &uglue, 3, __sF };
110 static struct glue *lastglue = &uglue;
111 #else
112 struct glue __sglue = { NULL, 3, __sF };
113 static struct glue *lastglue = &__sglue;
114 #endif
115
116 static struct glue * moreglue(int);
117
118 static spinlock_t thread_lock = _SPINLOCK_INITIALIZER;
119 #define THREAD_LOCK() if (__isthreaded) _SPINLOCK(&thread_lock)
120 #define THREAD_UNLOCK() if (__isthreaded) _SPINUNLOCK(&thread_lock)
121
122 #if NOT_YET
123 #define SET_GLUE_PTR(ptr, val) atomic_set_rel_ptr(&(ptr), (uintptr_t)(val))
124 #else
125 #define SET_GLUE_PTR(ptr, val) ptr = val
126 #endif
127
128 static struct glue *
129 moreglue(n)
130 int n;
131 {
132 struct glue *g;
133 static FILE empty;
134 FILE *p;
135 static struct __sFILEX emptyx = __sFXInit;
136 struct __sFILEX *fx;
137
138 g = (struct glue *)malloc(sizeof(*g) + ALIGNBYTES + n * sizeof(FILE) +
139 n * sizeof(struct __sFILEX));
140 if (g == NULL)
141 return (NULL);
142 p = (FILE *)ALIGN(g + 1);
143 fx = (struct __sFILEX *)&p[n];
144 g->next = NULL;
145 g->niobs = n;
146 g->iobs = p;
147
148 while (--n >= 0) {
149 *p = empty;
150 p->_extra = fx;
151 *p->_extra = emptyx;
152 p++, fx++;
153 }
154 return (g);
155 }
156
157 /*
158 * Find a free FILE for fopen et al.
159 */
160 FILE *
161 __sfp(int count)
162 {
163 FILE *fp;
164 int n;
165 struct glue *g;
166
167 if (!__sdidinit)
168 __sinit();
169
170 if (count) {
171 if (__scounted >= __stream_max) {
172 THREAD_UNLOCK();
173 errno = EMFILE;
174 return NULL;
175 }
176 OSAtomicIncrement32(&__scounted);
177 }
178 /*
179 * The list must be locked because a FILE may be updated.
180 */
181 THREAD_LOCK();
182 for (g = &__sglue; g != NULL; g = g->next) {
183 for (fp = g->iobs, n = g->niobs; --n >= 0; fp++)
184 if (fp->_flags == 0)
185 goto found;
186 }
187 THREAD_UNLOCK(); /* don't hold lock while malloc()ing. */
188 if ((g = moreglue(NDYNAMIC)) == NULL)
189 return (NULL);
190 THREAD_LOCK(); /* reacquire the lock */
191 SET_GLUE_PTR(lastglue->next, g); /* atomically append glue to list */
192 lastglue = g; /* not atomic; only accessed when locked */
193 fp = g->iobs;
194 found:
195 fp->_flags = 1; /* reserve this slot; caller sets real flags */
196 THREAD_UNLOCK();
197 fp->_p = NULL; /* no current pointer */
198 fp->_w = 0; /* nothing to read or write */
199 fp->_r = 0;
200 fp->_bf._base = NULL; /* no buffer */
201 fp->_bf._size = 0;
202 fp->_lbfsize = 0; /* not line buffered */
203 fp->_file = -1; /* no file */
204 /* fp->_cookie = <any>; */ /* caller sets cookie, _read/_write etc */
205 fp->_ub._base = NULL; /* no ungetc buffer */
206 fp->_ub._size = 0;
207 fp->_lb._base = NULL; /* no line buffer */
208 fp->_lb._size = 0;
209 /* fp->_lock = NULL; */ /* once set always set (reused) */
210 INITEXTRA(fp);
211 fp->_extra->counted = count ? 1 : 0;
212 return (fp);
213 }
214
215 /*
216 * Mark as free and update count as needed
217 */
218 __private_extern__ void
219 __sfprelease(FILE *fp)
220 {
221 if (fp->_counted) {
222 OSAtomicDecrement32(&__scounted);
223 fp->_counted = 0;
224 }
225 fp->_flags = 0;
226 }
227
228 /*
229 * XXX. Force immediate allocation of internal memory. Not used by stdio,
230 * but documented historically for certain applications. Bad applications.
231 */
232 __warn_references(f_prealloc,
233 "warning: this program uses f_prealloc(), which is not recommended.");
234
235 void
236 f_prealloc(void)
237 {
238 struct glue *g;
239 int n;
240
241 n = getdtablesize() - FOPEN_MAX + 20; /* 20 for slop. */
242 /*
243 * It should be safe to walk the list without locking it;
244 * new nodes are only added to the end and none are ever
245 * removed.
246 */
247 for (g = &__sglue; (n -= g->niobs) > 0 && g->next; g = g->next)
248 /* void */;
249 if ((n > 0) && ((g = moreglue(n)) != NULL)) {
250 THREAD_LOCK();
251 SET_GLUE_PTR(lastglue->next, g);
252 lastglue = g;
253 THREAD_UNLOCK();
254 }
255 }
256
257 /*
258 * exit() calls _cleanup() through *__cleanup, set whenever we
259 * open or buffer a file. This chicanery is done so that programs
260 * that do not use stdio need not link it all in.
261 *
262 * The name `_cleanup' is, alas, fairly well known outside stdio.
263 */
264 void
265 _cleanup()
266 {
267 /* (void) _fwalk(fclose); */
268 (void) _fwalk(__sflush); /* `cheating' */
269 }
270
271 /*
272 * __sinit() is called whenever stdio's internal variables must be set up.
273 */
274 void
275 __sinit()
276 {
277 THREAD_LOCK();
278 if (__sdidinit == 0) {
279 #if !TARGET_OS_EMBEDDED
280 int i;
281 #endif
282 /* Make sure we clean up on exit. */
283 __cleanup = _cleanup; /* conservative */
284 __stream_max = sysconf(_SC_STREAM_MAX);
285 __scounted = 3; /* std{in,out,err} already exists */
286
287 #if !TARGET_OS_EMBEDDED
288 /* Set _extra for the usual suspects. */
289 for (i = 0; i < FOPEN_MAX - 3; i++) {
290 usual[i]._extra = &usual_extra[i];
291 INITEXTRA(&usual[i]);
292 }
293 #endif
294
295 __sdidinit = 1;
296 }
297 THREAD_UNLOCK();
298 }