1 /* $NetBSD: findfp.c,v 1.28 2012/03/27 15:05:42 christos Exp $ */
2
3 /*-
4 * Copyright (c) 1990, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Chris Torek.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
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.
21 *
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
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35 #include <sys/cdefs.h>
36 #if defined(LIBC_SCCS) && !defined(lint)
37 #if 0
38 static char sccsid[] = "@(#)findfp.c 8.2 (Berkeley) 1/4/94";
39 #else
40 __RCSID("$NetBSD: findfp.c,v 1.28 2012/03/27 15:05:42 christos Exp $");
41 #endif
42 #endif /* LIBC_SCCS and not lint */
43
44 #include "namespace.h"
45 #include <sys/param.h>
46 #include <unistd.h>
47 #include <stdio.h>
48 #include <errno.h>
49 #include <stdlib.h>
50 #include <string.h>
51 #include "reentrant.h"
52 #include "local.h"
53 #include "glue.h"
54
55 int __sdidinit;
56
57 #define NDYNAMIC 10 /* add ten more whenever necessary */
58
59 #define std(flags, file) { \
60 ._p = NULL, \
61 ._r = 0, \
62 ._w = 0, \
63 ._flags = (flags), \
64 ._file = (file), \
65 ._bf = { ._base = NULL, ._size = 0 }, \
66 ._lbfsize = 0, \
67 ._cookie = __sF + (file), \
68 ._close = __sclose, \
69 ._read = __sread, \
70 ._seek = __sseek, \
71 ._write = __swrite, \
72 ._ext = { ._base = (void *)(__sFext + (file)), ._size = 0 }, \
73 ._up = NULL, \
74 ._ur = 0, \
75 ._ubuf = { [0] = '\0', [1] = '\0', [2] = '\0' }, \
76 ._nbuf = { [0] = '\0' }, \
77 ._flush = NULL, \
78 ._lb_unused = { '\0' }, \
79 ._blksize = 0, \
80 ._offset = (off_t)0, \
81 }
82
83 /* the usual - (stdin + stdout + stderr) */
84 static FILE usual[FOPEN_MAX - 3];
85 static struct __sfileext usualext[FOPEN_MAX - 3];
86 static struct glue uglue = { 0, FOPEN_MAX - 3, usual };
87
88 #if defined(_REENTRANT) && !defined(__lint__) /* XXX lint is busted */
89 #define STDEXT { ._lock = MUTEX_INITIALIZER, ._lockcond = COND_INITIALIZER }
90 struct __sfileext __sFext[3] = { STDEXT,
91 STDEXT,
92 STDEXT};
93 #else
94 struct __sfileext __sFext[3];
95 #endif
96
97 FILE __sF[3] = {
98 std(__SRD, STDIN_FILENO), /* stdin */
99 std(__SWR, STDOUT_FILENO), /* stdout */
100 std(__SWR|__SNBF, STDERR_FILENO) /* stderr */
101 };
102 struct glue __sglue = { &uglue, 3, __sF };
103
104 void f_prealloc(void);
105
106 #ifdef _REENTRANT
107 rwlock_t __sfp_lock = RWLOCK_INITIALIZER;
108 #endif
109
110 static struct glue *
moreglue(int n)111 moreglue(int n)
112 {
113 struct glue *g;
114 FILE *p;
115 struct __sfileext *pext;
116 static FILE empty;
117
118 g = malloc(sizeof(*g) + ALIGNBYTES + n * sizeof(FILE)
119 + n * sizeof(struct __sfileext));
120 if (g == NULL)
121 return NULL;
122 p = (FILE *)ALIGN((u_long)(g + 1));
123 g->next = NULL;
124 g->niobs = n;
125 g->iobs = p;
126 pext = (void *)(p + n);
127 while (--n >= 0) {
128 *p = empty;
129 _FILEEXT_SETUP(p, pext);
130 p++;
131 pext++;
132 }
133 return g;
134 }
135
136 void
__sfpinit(FILE * fp)137 __sfpinit(FILE *fp)
138 {
139 fp->_flags = 1; /* reserve this slot; caller sets real flags */
140 fp->_p = NULL; /* no current pointer */
141 fp->_w = 0; /* nothing to read or write */
142 fp->_r = 0;
143 fp->_bf._base = NULL; /* no buffer */
144 fp->_bf._size = 0;
145 fp->_lbfsize = 0; /* not line buffered */
146 fp->_file = -1; /* no file */
147 /* fp->_cookie = <any>; */ /* caller sets cookie, _read/_write etc */
148 fp->_flush = NULL; /* default flush */
149 _UB(fp)._base = NULL; /* no ungetc buffer */
150 _UB(fp)._size = 0;
151 memset(WCIO_GET(fp), 0, sizeof(struct wchar_io_data));
152 }
153
154 /*
155 * Find a free FILE for fopen et al.
156 */
157 FILE *
__sfp(void)158 __sfp(void)
159 {
160 FILE *fp;
161 int n;
162 struct glue *g;
163
164 if (!__sdidinit)
165 __sinit();
166
167 rwlock_wrlock(&__sfp_lock);
168 for (g = &__sglue;; g = g->next) {
169 for (fp = g->iobs, n = g->niobs; --n >= 0; fp++)
170 if (fp->_flags == 0)
171 goto found;
172 if (g->next == NULL && (g->next = moreglue(NDYNAMIC)) == NULL)
173 break;
174 }
175 rwlock_unlock(&__sfp_lock);
176 return NULL;
177 found:
178 __sfpinit(fp);
179 rwlock_unlock(&__sfp_lock);
180 return fp;
181 }
182
183 /*
184 * XXX. Force immediate allocation of internal memory. Not used by stdio,
185 * but documented historically for certain applications. Bad applications.
186 */
187 void
f_prealloc(void)188 f_prealloc(void)
189 {
190 struct glue *g;
191 int n;
192
193 n = (int)sysconf(_SC_OPEN_MAX) - FOPEN_MAX + 20; /* 20 for slop. */
194 for (g = &__sglue; (n -= g->niobs) > 0 && g->next; g = g->next)
195 continue;
196 if (n > 0)
197 g->next = moreglue(n);
198 }
199
200 /*
201 * exit() calls _cleanup() through *__cleanup, set whenever we
202 * open or buffer a file. This chicanery is done so that programs
203 * that do not use stdio need not link it all in.
204 *
205 * The name `_cleanup' is, alas, fairly well known outside stdio.
206 */
207 void
_cleanup(void)208 _cleanup(void)
209 {
210 /* (void) _fwalk(fclose); */
211 (void) fflush(NULL); /* `cheating' */
212 }
213
214 /*
215 * __sinit() is called whenever stdio's internal variables must be set up.
216 */
217 void
__sinit(void)218 __sinit(void)
219 {
220 int i;
221
222 for (i = 0; i < FOPEN_MAX - 3; i++)
223 _FILEEXT_SETUP(&usual[i], &usualext[i]);
224
225 /* make sure we clean up on exit */
226 __cleanup = _cleanup; /* conservative */
227 __sdidinit = 1;
228 }
229