1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License"). You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22 /*
23 * Copyright 1987 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 /* Copyright (c) 1984 AT&T */
28 /* All Rights Reserved */
29
30 #pragma ident "%Z%%M% %I% %E% SMI"
31
32 /*LINTLIBRARY*/
33 #include <stdio.h>
34 #include <errno.h>
35 #include <malloc.h>
36 #include "iob.h"
37
38 #define active(iop) ((iop)->_flag & (_IOREAD|_IOWRT|_IORW))
39
40 static unsigned char sbuf[NSTATIC][_SBFSIZ];
41 unsigned char (*_smbuf)[_SBFSIZ] = sbuf;
42 static FILE **iobglue;
43 static FILE **endglue;
44
45 /*
46 * Find a free FILE for fopen et al.
47 * We have a fixed static array of entries, and in addition
48 * may allocate additional entries dynamically, up to the kernel
49 * limit on the number of open files.
50 * At first just check for a free slot in the fixed static array.
51 * If none are available, then we allocate a structure to glue together
52 * the old and new FILE entries, which are then no longer contiguous.
53 */
54 FILE *
_findiop(void)55 _findiop(void)
56 {
57 FILE **iov, *iop;
58 FILE *fp;
59
60 if(iobglue == NULL) {
61 for(iop = _iob; iop < _iob + NSTATIC; iop++)
62 if(!active(iop))
63 return(iop);
64
65 if(_f_morefiles() == 0) {
66 errno = ENOMEM;
67 return(NULL);
68 }
69 }
70
71 iov = iobglue;
72 while(*iov != NULL && active(*iov))
73 if (++iov >= endglue) {
74 errno = EMFILE;
75 return(NULL);
76 }
77
78 if(*iov == NULL)
79 *iov = (FILE *)calloc(1, sizeof **iov);
80
81 return(*iov);
82 }
83
84 int
_f_morefiles(void)85 _f_morefiles(void)
86 {
87 FILE **iov;
88 FILE *fp;
89 unsigned char *cp;
90 int nfiles;
91
92 nfiles = getdtablesize();
93
94 iobglue = (FILE **)calloc(nfiles, sizeof *iobglue);
95 if(iobglue == NULL)
96 return(0);
97
98 if((_smbuf = (unsigned char (*)[_SBFSIZ])malloc(nfiles * sizeof *_smbuf)) == NULL) {
99 free((char *)iobglue);
100 iobglue = NULL;
101 return(0);
102 }
103
104 endglue = iobglue + nfiles;
105
106 for(fp = _iob, iov = iobglue; fp < &_iob[NSTATIC]; /* void */)
107 *iov++ = fp++;
108
109 return(1);
110 }
111
112 void
f_prealloc(void)113 f_prealloc(void)
114 {
115 FILE **iov;
116 FILE *fp;
117
118 if(iobglue == NULL && _f_morefiles() == 0)
119 return;
120
121 for(iov = iobglue; iov < endglue; iov++)
122 if(*iov == NULL)
123 *iov = (FILE *)calloc(1, sizeof **iov);
124 }
125
126 void
_fwalk(int (* function)(FILE *))127 _fwalk(int (*function)(FILE *))
128 {
129 FILE **iov;
130 FILE *fp;
131
132 if(function == NULL)
133 return;
134
135 if(iobglue == NULL) {
136 for(fp = _iob; fp < &_iob[NSTATIC]; fp++)
137 if(active(fp))
138 (*function)(fp);
139 } else {
140 for(iov = iobglue; iov < endglue; iov++)
141 if(*iov && active(*iov))
142 (*function)(*iov);
143 }
144 }
145