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 #if !defined(_LIBMINC) && !defined(__kernel__) && defined(__minix)
60
61 #define std(flags, file) { \
62 ._p = NULL, \
63 ._r = 0, \
64 ._w = 0, \
65 ._flags = (flags), \
66 ._file = (file), \
67 ._bf = { ._base = NULL, ._size = 0 }, \
68 ._lbfsize = 0, \
69 ._cookie = __sF + (file), \
70 ._close = __sclose, \
71 ._read = __sread, \
72 ._seek = __sseek, \
73 ._write = __swrite, \
74 ._ext = { ._base = (void *)(__sFext + (file)), ._size = 0 }, \
75 ._up = NULL, \
76 ._ur = 0, \
77 ._ubuf = { [0] = '\0', [1] = '\0', [2] = '\0' }, \
78 ._nbuf = { [0] = '\0' }, \
79 ._flush = NULL, \
80 ._lb_unused = { '\0' }, \
81 ._blksize = 0, \
82 ._offset = (off_t)0, \
83 }
84
85 #else
86
87 #define std(flags, file) { \
88 ._p = NULL, \
89 ._r = 0, \
90 ._w = 0, \
91 ._flags = (flags), \
92 ._file = (file), \
93 ._bf = { ._base = NULL, ._size = 0 }, \
94 ._lbfsize = 0, \
95 ._cookie = __sF + (file), \
96 ._close = NULL, \
97 ._read = NULL, \
98 ._seek = NULL, \
99 ._write = NULL, \
100 ._ext = { ._base = (void *)(__sFext + (file)), ._size = 0 }, \
101 ._up = NULL, \
102 ._ur = 0, \
103 ._ubuf = { [0] = '\0', [1] = '\0', [2] = '\0' }, \
104 ._nbuf = { [0] = '\0' }, \
105 ._flush = NULL, \
106 ._lb_unused = { '\0' }, \
107 ._blksize = 0, \
108 ._offset = (off_t)0, \
109 }
110
111 #endif /* !defined(_LIBMINC) && !defined(__kernel__) */
112
113 #if !defined(__kernel__) && defined(__minix)
114 /* the usual - (stdin + stdout + stderr) */
115 static FILE usual[FOPEN_MAX - 3];
116 static struct __sfileext usualext[FOPEN_MAX - 3];
117 static struct glue uglue = { 0, FOPEN_MAX - 3, usual };
118 #endif /* !defined(__kernel__) && defined(__minix) */
119
120 #if defined(_REENTRANT) && !defined(__lint__) /* XXX lint is busted */
121 #define STDEXT { ._lock = MUTEX_INITIALIZER, ._lockcond = COND_INITIALIZER }
122 struct __sfileext __sFext[3] = { STDEXT,
123 STDEXT,
124 STDEXT};
125 #else
126 struct __sfileext __sFext[3];
127 #endif
128
129 FILE __sF[3] = {
130 std(__SRD, STDIN_FILENO), /* stdin */
131 std(__SWR, STDOUT_FILENO), /* stdout */
132 std(__SWR|__SNBF, STDERR_FILENO) /* stderr */
133 };
134
135 #if !defined(__kernel__) && defined(__minix)
136 struct glue __sglue = { &uglue, 3, __sF };
137
138 void f_prealloc(void);
139
140 #ifdef _REENTRANT
141 rwlock_t __sfp_lock = RWLOCK_INITIALIZER;
142 #endif
143
144 static struct glue *
moreglue(int n)145 moreglue(int n)
146 {
147 struct glue *g;
148 FILE *p;
149 struct __sfileext *pext;
150 static FILE empty;
151
152 g = malloc(sizeof(*g) + ALIGNBYTES + n * sizeof(FILE)
153 + n * sizeof(struct __sfileext));
154 if (g == NULL)
155 return NULL;
156 p = (FILE *)ALIGN((u_long)(g + 1));
157 g->next = NULL;
158 g->niobs = n;
159 g->iobs = p;
160 pext = (void *)(p + n);
161 while (--n >= 0) {
162 *p = empty;
163 _FILEEXT_SETUP(p, pext);
164 p++;
165 pext++;
166 }
167 return g;
168 }
169
170 void
__sfpinit(FILE * fp)171 __sfpinit(FILE *fp)
172 {
173 fp->_flags = 1; /* reserve this slot; caller sets real flags */
174 fp->_p = NULL; /* no current pointer */
175 fp->_w = 0; /* nothing to read or write */
176 fp->_r = 0;
177 fp->_bf._base = NULL; /* no buffer */
178 fp->_bf._size = 0;
179 fp->_lbfsize = 0; /* not line buffered */
180 fp->_file = -1; /* no file */
181 /* fp->_cookie = <any>; */ /* caller sets cookie, _read/_write etc */
182 fp->_flush = NULL; /* default flush */
183 _UB(fp)._base = NULL; /* no ungetc buffer */
184 _UB(fp)._size = 0;
185 memset(WCIO_GET(fp), 0, sizeof(struct wchar_io_data));
186 }
187
188 /*
189 * Find a free FILE for fopen et al.
190 */
191 FILE *
__sfp(void)192 __sfp(void)
193 {
194 FILE *fp;
195 int n;
196 struct glue *g;
197
198 if (!__sdidinit)
199 __sinit();
200
201 rwlock_wrlock(&__sfp_lock);
202 for (g = &__sglue;; g = g->next) {
203 for (fp = g->iobs, n = g->niobs; --n >= 0; fp++)
204 if (fp->_flags == 0)
205 goto found;
206 if (g->next == NULL && (g->next = moreglue(NDYNAMIC)) == NULL)
207 break;
208 }
209 rwlock_unlock(&__sfp_lock);
210 return NULL;
211 found:
212 __sfpinit(fp);
213 rwlock_unlock(&__sfp_lock);
214 return fp;
215 }
216
217 /*
218 * XXX. Force immediate allocation of internal memory. Not used by stdio,
219 * but documented historically for certain applications. Bad applications.
220 */
221 void
f_prealloc(void)222 f_prealloc(void)
223 {
224 #if !defined(_LIBMINC) && defined(__minix)
225 struct glue *g;
226 int n;
227
228 n = (int)sysconf(_SC_OPEN_MAX) - FOPEN_MAX + 20; /* 20 for slop. */
229 for (g = &__sglue; (n -= g->niobs) > 0 && g->next; g = g->next)
230 continue;
231 if (n > 0)
232 g->next = moreglue(n);
233 #endif /* !defined(_LIBMINC) && defined(__minix) */
234 }
235
236 /*
237 * exit() calls _cleanup() through *__cleanup, set whenever we
238 * open or buffer a file. This chicanery is done so that programs
239 * that do not use stdio need not link it all in.
240 *
241 * The name `_cleanup' is, alas, fairly well known outside stdio.
242 */
243 void
_cleanup(void)244 _cleanup(void)
245 {
246 #if !defined(_LIBMINC) && defined(__minix)
247 /* (void) _fwalk(fclose); */
248 (void) fflush(NULL); /* `cheating' */
249 #endif /* !defined(_LIBMINC) && defined(__minix) */
250 }
251
252 /*
253 * __sinit() is called whenever stdio's internal variables must be set up.
254 */
255 void
__sinit(void)256 __sinit(void)
257 {
258 int i;
259
260 for (i = 0; i < FOPEN_MAX - 3; i++)
261 _FILEEXT_SETUP(&usual[i], &usualext[i]);
262
263 /* make sure we clean up on exit */
264 __cleanup = _cleanup; /* conservative */
265 __sdidinit = 1;
266 }
267 #endif /* !defined(__kernel__) && defined(__minix) */
268