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1 | /**************************************************************************** |
2 | ** | |
3 | ** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies). | |
4 | ** All rights reserved. | |
5 | ** | |
6 | ** Contact: Nokia Corporation (qt-info@nokia.com) | |
7 | ** | |
8 | ** This file is part of a Qt Solutions component. | |
9 | ** | |
10 | ** You may use this file under the terms of the BSD license as follows: | |
11 | ** | |
12 | ** "Redistribution and use in source and binary forms, with or without | |
13 | ** modification, are permitted provided that the following conditions are | |
14 | ** met: | |
15 | ** * Redistributions of source code must retain the above copyright | |
16 | ** notice, this list of conditions and the following disclaimer. | |
17 | ** * Redistributions in binary form must reproduce the above copyright | |
18 | ** notice, this list of conditions and the following disclaimer in | |
19 | ** the documentation and/or other materials provided with the | |
20 | ** distribution. | |
21 | ** * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor | |
22 | ** the names of its contributors may be used to endorse or promote | |
23 | ** products derived from this software without specific prior written | |
24 | ** permission. | |
25 | ** | |
26 | ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
27 | ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
28 | ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR | |
29 | ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT | |
30 | ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | |
31 | ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT | |
32 | ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
33 | ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
34 | ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
35 | ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | |
36 | ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE." | |
37 | ** | |
38 | ****************************************************************************/ | |
39 | ||
40 | #include <string.h> | |
41 | #include <errno.h> | |
42 | #include <unistd.h> | |
43 | #include <fcntl.h> | |
44 | ||
45 | #include "qtlockedfile.h" | |
46 | ||
47 | bool QtLockedFile::lock(LockMode mode, bool block) | |
48 | { | |
49 | if (!isOpen()) { | |
50 | qWarning("QtLockedFile::lock(): file is not opened"); | |
51 | return false; | |
52 | } | |
53 | ||
54 | if (mode == NoLock) | |
55 | return unlock(); | |
56 | ||
57 | if (mode == m_lock_mode) | |
58 | return true; | |
59 | ||
60 | if (m_lock_mode != NoLock) | |
61 | unlock(); | |
62 | ||
63 | struct flock fl; | |
64 | fl.l_whence = SEEK_SET; | |
65 | fl.l_start = 0; | |
66 | fl.l_len = 0; | |
67 | fl.l_type = (mode == ReadLock) ? F_RDLCK : F_WRLCK; | |
68 | int cmd = block ? F_SETLKW : F_SETLK; | |
69 | int ret = fcntl(handle(), cmd, &fl); | |
70 | ||
71 | if (ret == -1) { | |
72 | if (errno != EINTR && errno != EAGAIN) | |
73 | qWarning("QtLockedFile::lock(): fcntl: %s", strerror(errno)); | |
74 | return false; | |
75 | } | |
76 | ||
77 | ||
78 | m_lock_mode = mode; | |
79 | return true; | |
80 | } | |
81 | ||
82 | ||
83 | bool QtLockedFile::unlock() | |
84 | { | |
85 | if (!isOpen()) { | |
86 | qWarning("QtLockedFile::unlock(): file is not opened"); | |
87 | return false; | |
88 | } | |
89 | ||
90 | if (!isLocked()) | |
91 | return true; | |
92 | ||
93 | struct flock fl; | |
94 | fl.l_whence = SEEK_SET; | |
95 | fl.l_start = 0; | |
96 | fl.l_len = 0; | |
97 | fl.l_type = F_UNLCK; | |
98 | int ret = fcntl(handle(), F_SETLKW, &fl); | |
99 | ||
100 | if (ret == -1) { | |
101 | qWarning("QtLockedFile::lock(): fcntl: %s", strerror(errno)); | |
102 | return false; | |
103 | } | |
104 | ||
105 | m_lock_mode = NoLock; | |
106 | return true; | |
107 | } | |
108 | ||
109 | QtLockedFile::~QtLockedFile() | |
110 | { | |
111 | if (isOpen()) | |
112 | unlock(); | |
113 | } | |
114 |