Rev 108 | Details | Compare with Previous | Last modification | View Log | RSS feed
| 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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| 108 | luk | 6 | * Copyright (C) 2007, 2008, 2012 Lukas Jelinek, <lukas@aiken.cz> |
| 69 | luk | 7 | * |
| 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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| 108 | luk | 18 | * Credits: |
| 19 | * Christian Ruppert (new include to build with GCC 4.4+) |
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| 20 | * |
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| 69 | luk | 21 | */ |
| 22 | |||
| 23 | |||
| 24 | #include <fcntl.h> |
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| 25 | #include <unistd.h> |
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| 26 | #include <errno.h> |
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| 27 | #include <signal.h> |
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| 108 | luk | 28 | #include <cstdio> |
| 69 | luk | 29 | |
| 30 | #include "appinst.h" |
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| 31 | |||
| 73 | luk | 32 | /// Lockfile permissions (currently 0644) |
| 33 | #define APPLOCK_PERM (S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH) |
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| 69 | luk | 34 | |
| 35 | |||
| 71 | luk | 36 | AppInstance::AppInstance(const std::string& rName, const std::string& rBase) |
| 37 | : m_fLocked(false) |
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| 69 | luk | 38 | { |
| 71 | luk | 39 | std::string base(rBase); |
| 40 | if (base.empty()) |
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| 41 | base = APPLOCK_BASEDIR; |
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| 69 | luk | 42 | |
| 71 | luk | 43 | if (base[base.length()-1] == '/') |
| 44 | m_path = base + rName + ".pid"; |
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| 45 | else |
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| 46 | m_path = base + "/" + rName + ".pid"; |
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| 69 | luk | 47 | } |
| 48 | |||
| 49 | AppInstance::~AppInstance() |
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| 50 | { |
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| 51 | try { |
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| 52 | Unlock(); |
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| 53 | } catch (AppInstException e) {} |
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| 54 | } |
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| 55 | |||
| 71 | luk | 56 | bool AppInstance::DoLock() |
| 69 | luk | 57 | { |
| 73 | luk | 58 | int fd = open(m_path.c_str(), O_WRONLY | O_CREAT | O_EXCL, APPLOCK_PERM); |
| 69 | luk | 59 | if (fd != -1) { |
| 60 | FILE* f = fdopen(fd, "w"); |
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| 61 | if (f == NULL) { |
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| 62 | AppInstException e(errno); |
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| 63 | close(fd); |
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| 64 | throw e; |
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| 65 | } |
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| 66 | |||
| 67 | if (fprintf(f, "%u", (unsigned) getpid()) <= 0) { |
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| 68 | AppInstException e(errno); |
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| 69 | fclose(f); |
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| 70 | throw e; |
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| 71 | } |
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| 72 | |||
| 73 | if (fclose(f) != 0) |
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| 74 | throw AppInstException(errno); |
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| 75 | |||
| 76 | m_fLocked = true; |
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| 77 | return true; |
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| 78 | } |
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| 79 | |||
| 80 | if (errno != EEXIST) |
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| 81 | throw AppInstException(errno); |
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| 82 | |||
| 83 | return false; |
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| 84 | } |
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| 85 | |||
| 86 | bool AppInstance::Lock() |
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| 87 | { |
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| 88 | for (int i=0; i<100; i++) { |
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| 71 | luk | 89 | if (DoLock()) |
| 69 | luk | 90 | return true; |
| 91 | |||
| 71 | luk | 92 | FILE* f = fopen(m_path.c_str(), "r"); |
| 69 | luk | 93 | if (f == NULL) { |
| 94 | if (errno != ENOENT) |
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| 95 | throw AppInstException(errno); |
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| 96 | } |
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| 97 | else { |
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| 98 | unsigned pid; |
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| 99 | ssize_t len = fscanf(f, "%u", &pid); |
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| 100 | if (len == -1) { |
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| 101 | AppInstException e(errno); |
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| 102 | fclose(f); |
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| 103 | throw e; |
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| 104 | } |
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| 105 | else if (len == 0) { |
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| 106 | AppInstException e(EIO); |
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| 107 | fclose(f); |
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| 108 | throw e; |
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| 109 | } |
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| 110 | |||
| 111 | fclose(f); |
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| 112 | |||
| 113 | int res = kill((pid_t) pid, 0); |
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| 114 | if (res == 0) |
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| 115 | return false; |
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| 116 | |||
| 117 | if (errno != ESRCH) |
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| 118 | throw AppInstException(errno); |
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| 119 | |||
| 71 | luk | 120 | res = unlink(m_path.c_str()); |
| 69 | luk | 121 | if (res != 0 && errno != ENOENT) |
| 122 | throw AppInstException(errno); |
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| 123 | } |
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| 124 | } |
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| 125 | |||
| 126 | return false; |
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| 127 | } |
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| 128 | |||
| 129 | void AppInstance::Unlock() |
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| 130 | { |
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| 131 | if (!m_fLocked) |
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| 132 | return; |
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| 133 | |||
| 71 | luk | 134 | if (unlink(m_path.c_str()) != 0 && errno != ENOENT) |
| 69 | luk | 135 | throw AppInstException(errno); |
| 136 | |||
| 137 | m_fLocked = false; |
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| 138 | } |
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| 139 | |||
| 140 | bool AppInstance::Exists() const |
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| 141 | { |
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| 142 | if (m_fLocked) |
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| 143 | return true; |
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| 144 | |||
| 71 | luk | 145 | FILE* f = fopen(m_path.c_str(), "r"); |
| 69 | luk | 146 | if (f == NULL) { |
| 147 | if (errno == ENOENT) |
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| 148 | return false; |
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| 149 | else |
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| 150 | throw AppInstException(errno); |
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| 151 | } |
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| 152 | |||
| 153 | bool ok = false; |
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| 154 | |||
| 155 | unsigned pid; |
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| 156 | if (fscanf(f, "%u", &pid) == 1) { |
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| 157 | if (kill((pid_t) pid, 0) == 0) |
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| 158 | ok = true; |
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| 159 | else if (errno != ESRCH) { |
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| 160 | AppInstException e(errno); |
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| 161 | fclose(f); |
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| 162 | throw e; |
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| 163 | } |
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| 164 | } |
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| 165 | |||
| 166 | fclose(f); |
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| 167 | |||
| 168 | return ok; |
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| 169 | } |
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| 170 | |||
| 171 | bool AppInstance::SendSignal(int iSigNo) const |
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| 172 | { |
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| 71 | luk | 173 | FILE* f = fopen(m_path.c_str(), "r"); |
| 69 | luk | 174 | if (f == NULL) { |
| 175 | if (errno == ENOENT) |
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| 176 | return false; |
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| 177 | else |
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| 178 | throw AppInstException(errno); |
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| 179 | } |
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| 180 | |||
| 181 | bool ok = false; |
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| 182 | |||
| 183 | unsigned pid; |
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| 184 | if (fscanf(f, "%u", &pid) == 1) { |
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| 185 | if (pid != (unsigned) getpid()) { |
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| 186 | if (kill((pid_t) pid, iSigNo) == 0) { |
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| 187 | ok = true; |
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| 188 | } |
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| 189 | else if (errno != ESRCH) { |
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| 190 | AppInstException e(errno); |
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| 191 | fclose(f); |
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| 192 | throw e; |
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| 193 | } |
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| 194 | } |
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| 195 | } |
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| 196 | |||
| 197 | fclose(f); |
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| 198 | |||
| 199 | return ok; |
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| 200 | } |
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| 201 |