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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 69 | luk | 1 | |
| 2 | /// Application instance class implementation |
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| 3 | /** |
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| 4 | * \file appinst.cpp |
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| 5 | * |
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| 6 | * Copyright (C) 2007 Lukas Jelinek, <lukas@aiken.cz> |
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| 7 | * |
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| 8 | * This program is free software; you can redistribute it and/or |
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| 9 | * modify it under the terms of one of the following licenses: |
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| 10 | * |
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| 11 | * \li 1. X11-style license (see LICENSE-X11) |
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| 12 | * \li 2. GNU Lesser General Public License, version 2.1 (see LICENSE-LGPL) |
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| 13 | * \li 3. GNU General Public License, version 2 (see LICENSE-GPL) |
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| 14 | * |
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| 15 | * If you want to help with choosing the best license for you, |
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| 16 | * please visit http://www.gnu.org/licenses/license-list.html. |
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| 17 | * |
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| 18 | */ |
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| 19 | |||
| 20 | |||
| 21 | #include <fcntl.h> |
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| 22 | #include <unistd.h> |
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| 23 | #include <stdio.h> |
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| 24 | #include <errno.h> |
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| 25 | #include <signal.h> |
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| 26 | |||
| 27 | #include "appinst.h" |
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| 28 | |||
| 29 | #ifdef APPINST_LOCK_DIRECTORY |
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| 30 | #define LOCKDIR APPINST_LOCK_DIRECTORY |
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| 31 | #else |
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| 32 | #define LOCKDIR "/tmp" |
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| 33 | #endif // APPINST_LOCK_DIRECTORY |
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| 34 | |||
| 35 | |||
| 36 | |||
| 37 | AppInstance::AppInstance(const std::string& rName) |
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| 38 | : m_name(rName), |
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| 39 | m_fLocked(false) |
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| 40 | { |
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| 41 | |||
| 42 | } |
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| 43 | |||
| 44 | AppInstance::~AppInstance() |
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| 45 | { |
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| 46 | try { |
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| 47 | Unlock(); |
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| 48 | } catch (AppInstException e) {} |
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| 49 | } |
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| 50 | |||
| 51 | bool AppInstance::DoLock(const char* path) |
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| 52 | { |
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| 53 | int fd = open(path, O_WRONLY | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR); |
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| 54 | if (fd != -1) { |
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| 55 | FILE* f = fdopen(fd, "w"); |
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| 56 | if (f == NULL) { |
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| 57 | AppInstException e(errno); |
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| 58 | close(fd); |
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| 59 | throw e; |
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| 60 | } |
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| 61 | |||
| 62 | if (fprintf(f, "%u", (unsigned) getpid()) <= 0) { |
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| 63 | AppInstException e(errno); |
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| 64 | fclose(f); |
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| 65 | throw e; |
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| 66 | } |
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| 67 | |||
| 68 | if (fclose(f) != 0) |
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| 69 | throw AppInstException(errno); |
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| 70 | |||
| 71 | m_fLocked = true; |
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| 72 | return true; |
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| 73 | } |
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| 74 | |||
| 75 | if (errno != EEXIST) |
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| 76 | throw AppInstException(errno); |
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| 77 | |||
| 78 | return false; |
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| 79 | } |
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| 80 | |||
| 81 | bool AppInstance::Lock() |
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| 82 | { |
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| 83 | std::string fn = GetLockfile(); |
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| 84 | |||
| 85 | for (int i=0; i<100; i++) { |
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| 86 | if (DoLock(fn.c_str())) |
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| 87 | return true; |
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| 88 | |||
| 89 | FILE* f = fopen(fn.c_str(), "r"); |
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| 90 | if (f == NULL) { |
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| 91 | if (errno != ENOENT) |
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| 92 | throw AppInstException(errno); |
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| 93 | } |
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| 94 | else { |
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| 95 | unsigned pid; |
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| 96 | ssize_t len = fscanf(f, "%u", &pid); |
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| 97 | if (len == -1) { |
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| 98 | AppInstException e(errno); |
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| 99 | fclose(f); |
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| 100 | throw e; |
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| 101 | } |
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| 102 | else if (len == 0) { |
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| 103 | AppInstException e(EIO); |
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| 104 | fclose(f); |
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| 105 | throw e; |
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| 106 | } |
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| 107 | |||
| 108 | fclose(f); |
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| 109 | |||
| 110 | int res = kill((pid_t) pid, 0); |
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| 111 | if (res == 0) |
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| 112 | return false; |
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| 113 | |||
| 114 | if (errno != ESRCH) |
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| 115 | throw AppInstException(errno); |
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| 116 | |||
| 117 | res = unlink(fn.c_str()); |
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| 118 | if (res != 0 && errno != ENOENT) |
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| 119 | throw AppInstException(errno); |
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| 120 | } |
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| 121 | } |
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| 122 | |||
| 123 | return false; |
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| 124 | } |
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| 125 | |||
| 126 | void AppInstance::Unlock() |
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| 127 | { |
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| 128 | if (!m_fLocked) |
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| 129 | return; |
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| 130 | |||
| 131 | if (unlink(GetLockfile().c_str()) != 0 && errno != ENOENT) |
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| 132 | throw AppInstException(errno); |
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| 133 | |||
| 134 | m_fLocked = false; |
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| 135 | } |
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| 136 | |||
| 137 | bool AppInstance::Exists() const |
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| 138 | { |
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| 139 | if (m_fLocked) |
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| 140 | return true; |
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| 141 | |||
| 142 | FILE* f = fopen(GetLockfile().c_str(), "r"); |
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| 143 | if (f == NULL) { |
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| 144 | if (errno == ENOENT) |
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| 145 | return false; |
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| 146 | else |
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| 147 | throw AppInstException(errno); |
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| 148 | } |
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| 149 | |||
| 150 | bool ok = false; |
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| 151 | |||
| 152 | unsigned pid; |
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| 153 | if (fscanf(f, "%u", &pid) == 1) { |
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| 154 | if (kill((pid_t) pid, 0) == 0) |
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| 155 | ok = true; |
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| 156 | else if (errno != ESRCH) { |
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| 157 | AppInstException e(errno); |
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| 158 | fclose(f); |
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| 159 | throw e; |
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| 160 | } |
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| 161 | } |
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| 162 | |||
| 163 | fclose(f); |
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| 164 | |||
| 165 | return ok; |
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| 166 | } |
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| 167 | |||
| 168 | bool AppInstance::SendSignal(int iSigNo) const |
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| 169 | { |
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| 170 | FILE* f = fopen(GetLockfile().c_str(), "r"); |
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| 171 | if (f == NULL) { |
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| 172 | if (errno == ENOENT) |
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| 173 | return false; |
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| 174 | else |
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| 175 | throw AppInstException(errno); |
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| 176 | } |
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| 177 | |||
| 178 | bool ok = false; |
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| 179 | |||
| 180 | unsigned pid; |
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| 181 | if (fscanf(f, "%u", &pid) == 1) { |
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| 182 | if (pid != (unsigned) getpid()) { |
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| 183 | if (kill((pid_t) pid, iSigNo) == 0) { |
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| 184 | ok = true; |
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| 185 | } |
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| 186 | else if (errno != ESRCH) { |
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| 187 | AppInstException e(errno); |
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| 188 | fclose(f); |
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| 189 | throw e; |
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| 190 | } |
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| 191 | } |
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| 192 | } |
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| 193 | |||
| 194 | fclose(f); |
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| 195 | |||
| 196 | return ok; |
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| 197 | } |
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| 198 | |||
| 199 | std::string AppInstance::GetLockfile() const |
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| 200 | { |
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| 201 | return std::string(LOCKDIR) + "/" + m_name + ".pid"; |
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| 202 | } |