Branch data Line data Source code
1 : : /*
2 : : * Copyright (c) 2016, Citrix Systems, Inc.
3 : : *
4 : : * All rights reserved.
5 : : *
6 : : * Redistribution and use in source and binary forms, with or without
7 : : * modification, are permitted provided that the following conditions are met:
8 : : *
9 : : * 1. Redistributions of source code must retain the above copyright
10 : : * notice, this list of conditions and the following disclaimer.
11 : : * 2. Redistributions in binary form must reproduce the above copyright
12 : : * notice, this list of conditions and the following disclaimer in the
13 : : * documentation and/or other materials provided with the distribution.
14 : : * 3. Neither the name of the copyright holder nor the names of its
15 : : * contributors may be used to endorse or promote products derived from
16 : : * this software without specific prior written permission.
17 : : *
18 : : * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 : : * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 : : * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 : : * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
22 : : * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
23 : : * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
24 : : * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
25 : : * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
26 : : * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
27 : : * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
28 : : * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 : : */
30 : :
31 : : #ifdef HAVE_CONFIG_H
32 : : #include "config.h"
33 : : #endif
34 : :
35 : : #include <stdio.h>
36 : : #include <errno.h>
37 : :
38 : : #include "tap-ctl.h"
39 : :
40 : : int
41 : 0 : tap_ctl_blk_major(void)
42 : : {
43 : : FILE *devices;
44 : : int rv, major;
45 : :
46 : 0 : devices = fopen("/proc/devices", "r");
47 : 0 : if (!devices) {
48 : 0 : rv = -errno;
49 : 0 : goto out;
50 : : }
51 : :
52 : : do {
53 : : char buf[32], *s;
54 : : int n, offset;
55 : :
56 : 0 : s = fgets(buf, sizeof(buf), devices);
57 : 0 : if (!s)
58 : : break;
59 : :
60 : 0 : major = -ENODEV;
61 : 0 : offset = 0;
62 : :
63 : 0 : n = sscanf(buf, "%d tapdev%n", &major, &offset);
64 : 0 : if (n == 1 && offset)
65 : : break;
66 : 0 : } while (1);
67 : :
68 : 0 : rv = major;
69 : :
70 : : out:
71 : 0 : if (devices)
72 : 0 : fclose(devices);
73 : :
74 : 0 : return rv;
75 : : }
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