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 : : #include <fcntl.h>
38 : : #include <stdlib.h>
39 : : #include <unistd.h>
40 : : #include <sys/file.h>
41 : :
42 : : #include "tap-ctl.h"
43 : : #include "blktap.h"
44 : :
45 : : int
46 : 3 : tap_ctl_free(const int minor)
47 : : {
48 : 3 : char *path = NULL;
49 : 3 : int mfd = -1, fd, err;
50 : :
51 : 3 : fd = open(BLKTAP2_NP_RUN_DIR, O_RDONLY);
52 [ + + ]: 3 : if (fd == -1) {
53 : 1 : err = -errno;
54 : 1 : EPRINTF("Failed to open runtime directory %d\n", errno);
55 : 3 : return err;
56 : : }
57 : :
58 : : /* The only way this can fail is with an EINTR or ENOLCK*/
59 : 2 : err = flock(fd, LOCK_EX);
60 [ - + ]: 2 : if (err == -1) {
61 : 0 : err = -errno;
62 : 0 : EPRINTF("Failed to lock runtime directory %d\n", errno);
63 : : return err;
64 : : }
65 : :
66 : 2 : err = asprintf(&path, "%s/tapdisk-%d", BLKTAP2_NP_RUN_DIR, minor);
67 [ - + ]: 2 : if (err == -1) {
68 : 0 : err = -errno;
69 : 0 : goto out;
70 : : }
71 : 2 : err = 0;
72 : :
73 : : /* Non-Blocking lock to check it's not in use */
74 : 4 : mfd = open(path, O_RDONLY);
75 [ - + ]: 2 : if (mfd == -1) {
76 : 0 : err = -errno;
77 : 0 : EPRINTF("Failed to open marker file %s, %d, err=%d\n",
78 : : path, minor, errno);
79 : : goto out;
80 : : }
81 : :
82 : 2 : err = flock(mfd, LOCK_EX | LOCK_NB);
83 [ + + ]: 2 : if (err == -1) {
84 : 1 : err = -errno;
85 : 1 : EPRINTF("Unable to lock marker file %s, err = %d\n",
86 : : path, errno);
87 : : goto out;
88 : : }
89 : :
90 : 1 : unlink(path);
91 : :
92 : : out:
93 [ + - ]: 2 : if (path)
94 : 2 : free(path);
95 : :
96 [ + - ]: 2 : if (mfd != -1) {
97 : 2 : flock(mfd, LOCK_UN);
98 : 2 : close(mfd);
99 : : }
100 : :
101 : 2 : flock(fd, LOCK_UN);
102 : 2 : close(fd);
103 : : return err;
104 : : }
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