summaryrefslogtreecommitdiff
path: root/mit-pthreads/stdio/findfp.c
blob: 35817eb6a5f3e3927bf1cf5dca16a09d84b26496 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
/*-
 * Copyright (c) 1990 The Regents of the University of California.
 * Copyright (c) 1993, 1994 Chris Provenzano. 
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Chris Torek.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#if defined(LIBC_SCCS) && !defined(lint)
/*static char *sccsid = "from: @(#)findfp.c	5.10 (Berkeley) 2/24/91";*/
static char *rcsid = "$Id$";
#endif /* LIBC_SCCS and not lint */

#include <pthread.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include "local.h"
#include "glue.h"


#define NSTATIC	20	/* stdin + stdout + stderr + the usual */
#define	NDYNAMIC 10	/* add ten more whenever necessary */

#define	std(flags, file) \
	{0,0,0,flags,file,{0},0 }
/*	 p r w flags file _bf z  */

static FILE usual[NSTATIC - 3];	/* the usual */
static struct glue uglue = { 0, NSTATIC - 3, usual };

FILE __sF[3] = {
	std(__SRD, 0),		/* stdin */
	std(__SWR, 1),		/* stdout */
	std(__SWR|__SNBF, 2)	/* stderr */
};
struct glue __sglue = { &uglue, 3, __sF };
FILE *__iob = __sF;
FILE *_iob = __sF;

pthread_mutex_t __sfp_mutex = PTHREAD_MUTEX_INITIALIZER;
pthread_cond_t 	__sfp_cond	= PTHREAD_COND_INITIALIZER;
/*
 * __sfp_state = 0, when free, > 0 when in _fwalk 
 * This allows multiple readers in _fwalk, but only one writer __sfp,
 * or freopen() at a time.
 */
int	__sfp_state = 0;

static struct glue *moreglue(register int n)
{
	register struct glue *g;
	register FILE *p;
	static FILE empty;

	g = (struct glue *)malloc(sizeof(struct glue) + n * sizeof(FILE));
	if (g == NULL)
		return (NULL);
	p = (FILE *)(g + 1);
	g->next = NULL;
	g->niobs = n;
	g->iobs = p;
	while (--n >= 0)
		*p++ = empty;
	return (g);
}

/*
 * Find a free FILE for fopen et al.
 */
FILE *__sfp()
{
	register FILE *fp;
	register int n;
	register struct glue *g;

	for (g = &__sglue;; g = g->next) {
		for (fp = g->iobs, n = g->niobs; --n >= 0; fp++)
			if (fp->_flags == 0) {
				fp->_flags = 1;		/* reserve this slot; caller sets real flags */
				fp->_p = NULL;		/* no current pointer */
				fp->_w = 0;		/* nothing to read or write */
				fp->_r = 0;
				fp->_bf._base = NULL;	/* no buffer */
				fp->_bf._size = 0;
				fp->_lbfsize = 0;	/* not line buffered */
				fp->_file = -1;		/* no file */
				fp->_ub._base = NULL;	/* no ungetc buffer */
				fp->_ub._size = 0;
				fp->_lb._base = NULL;	/* no line buffer */
				fp->_lb._size = 0;
				goto __sfp_done;
			}
		if (g->next == NULL && (g->next = moreglue(NDYNAMIC)) == NULL) {
			fp = NULL;
			break;
		}
	}
__sfp_done:;
	return (fp);
}

/*
 * exit() calls _cleanup() through *__cleanup, set whenever we
 * open or buffer a file.  This chicanery is done so that programs
 * that do not use stdio need not link it all in.
 *
 * The name `_cleanup' is, alas, fairly well known outside stdio.
 */
void _cleanup()
{
	(void) __swalk_sflush();
}

/*
 * __sinit() is called whenever stdio's internal variables must be set up.
 * Do the pthread_once stuff here to keep pthread_once_t out of the
 * header files.  No reason sprintf.c &c should need to include pthread.h...
 */
static void __s_real_init ()
{
    /* make sure we clean up on exit */
    __cleanup = _cleanup;
}

static pthread_once_t sdidinit = PTHREAD_ONCE_INIT;

void __sinit ()
{
    pthread_once (&sdidinit, __s_real_init);
}