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
40int 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
96puke:
97    close(fd);
98    return -1;
99}
100