diff options
Diffstat (limited to 'qpid/cpp/src/qpid/sys/posix/LockFile.cpp')
-rwxr-xr-x | qpid/cpp/src/qpid/sys/posix/LockFile.cpp | 108 |
1 files changed, 108 insertions, 0 deletions
diff --git a/qpid/cpp/src/qpid/sys/posix/LockFile.cpp b/qpid/cpp/src/qpid/sys/posix/LockFile.cpp new file mode 100755 index 0000000000..1862ff6ac9 --- /dev/null +++ b/qpid/cpp/src/qpid/sys/posix/LockFile.cpp @@ -0,0 +1,108 @@ +/* + * + * Copyright (c) 2008 The Apache Software Foundation + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + * + */ + +#include "qpid/sys/LockFile.h" +#include "qpid/sys/posix/PidFile.h" + +#include <string> +#include <unistd.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> + +#include "qpid/sys/posix/check.h" + +namespace qpid { +namespace sys { + +class LockFilePrivate { + friend class LockFile; + friend class PidFile; + + int fd; + +public: + LockFilePrivate(int f) : fd(f) {} +}; + +LockFile::LockFile(const std::string& path_, bool create) + : path(path_), created(create) { + + errno = 0; + int flags=create ? O_WRONLY|O_CREAT|O_NOFOLLOW : O_RDWR; + int fd = ::open(path.c_str(), flags, 0644); + if (fd < 0) throw ErrnoException("Cannot open " + path, errno); + if (::lockf(fd, F_TLOCK, 0) < 0) { + ::close(fd); + throw ErrnoException("Cannot lock " + path, errno); + } + impl.reset(new LockFilePrivate(fd)); +} + +LockFile::~LockFile() { + if (impl) { + int f = impl->fd; + if (f >= 0) { + int unused_ret; + unused_ret = ::lockf(f, F_ULOCK, 0); // Suppress warnings about ignoring return value. + ::close(f); + impl->fd = -1; + } + } +} + +int LockFile::read(void* bytes, size_t len) const { + if (!impl) + throw Exception("Lock file not open: " + path); + + ssize_t rc = ::read(impl->fd, bytes, len); + if ((ssize_t)len > rc) { + throw Exception("Cannot read lock file: " + path); + } + return rc; +} + +int LockFile::write(void* bytes, size_t len) const { + if (!impl) + throw Exception("Lock file not open: " + path); + + ssize_t rc = ::write(impl->fd, bytes, len); + if ((ssize_t)len > rc) { + throw Exception("Cannot write lock file: " + path); + } + return rc; +} + +PidFile::PidFile(const std::string& path_, bool create): + LockFile(path_, create) +{} + +pid_t PidFile::readPid(void) const { + pid_t pid; + int desired_read = sizeof(pid_t); + read(&pid, desired_read); + return pid; +} + +void PidFile::writePid(void) { + pid_t pid = getpid(); + int desired_write = sizeof(pid_t); + write(&pid, desired_write); +} + +}} /* namespace qpid::sys */ |