1 /* ----------------------------------------------------------------------- *
2 *
3 * Copyright 2003-2008 H. Peter Anvin - All Rights Reserved
4 *
5 * Permission is hereby granted, free of charge, to any person
6 * obtaining a copy of this software and associated documentation
7 * files (the "Software"), to deal in the Software without
8 * restriction, including without limitation the rights to use,
9 * copy, modify, merge, publish, distribute, sublicense, and/or
10 * sell copies of the Software, and to permit persons to whom
11 * the Software is furnished to do so, subject to the following
12 * conditions:
13 *
14 * The above copyright notice and this permission notice shall
15 * be included in all copies or substantial portions of the Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
18 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
19 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
20 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
21 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
22 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
23 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
24 * OTHER DEALINGS IN THE SOFTWARE.
25 *
26 * ----------------------------------------------------------------------- */
27
28 #include <errno.h>
29 #include <com32.h>
30 #include <string.h>
31 #include <unistd.h>
32 #include "file.h"
33
34 /*
35 * opendev.c
36 *
37 * Open a special device
38 */
39
opendev(const struct input_dev * idev,const struct output_dev * odev,int flags)40 int opendev(const struct input_dev *idev,
41 const struct output_dev *odev, int flags)
42 {
43 int fd;
44 struct file_info *fp;
45 int okflags;
46 int e;
47
48 okflags = (idev ? idev->fileflags : 0) | (odev ? odev->fileflags : 0);
49
50 if (!(flags & 3) || (flags & ~okflags)) {
51 errno = EINVAL;
52 return -1;
53 }
54
55 for (fd = 0, fp = __file_info; fd < NFILES; fd++, fp++)
56 if (!fp->iop && !fp->oop)
57 break;
58
59 if (fd >= NFILES) {
60 errno = EMFILE;
61 return -1;
62 }
63
64 /* The file structure is already zeroed */
65 fp->iop = &dev_error_r;
66 fp->oop = &dev_error_w;
67 fp->i.datap = fp->i.buf;
68
69 if (idev) {
70 if (idev->open && (e = idev->open(fp))) {
71 errno = e;
72 goto puke;
73 }
74 fp->iop = idev;
75 }
76
77 while (odev) {
78 if (odev->open && (e = odev->open(fp))) {
79 if (e == EAGAIN) {
80 if (odev->fallback) {
81 odev = odev->fallback;
82 continue;
83 } else {
84 e = EIO;
85 }
86 }
87 errno = e;
88 goto puke;
89 }
90 fp->oop = odev;
91 break;
92 }
93
94 return fd;
95
96 puke:
97 close(fd);
98 return -1;
99 }
100