Kea 2.7.0
pid_file.cc
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1// Copyright (C) 2015 Internet Systems Consortium, Inc. ("ISC")
2//
3// This Source Code Form is subject to the terms of the Mozilla Public
4// License, v. 2.0. If a copy of the MPL was not distributed with this
5// file, You can obtain one at http://mozilla.org/MPL/2.0/.
6
7#include <config.h>
8
9#include <util/pid_file.h>
10#include <cstdio>
11#include <signal.h>
12#include <unistd.h>
13#include <cerrno>
14
15namespace isc {
16namespace util {
17
18PIDFile::PIDFile(const std::string& filename)
19 : filename_(filename) {
20}
21
24
25int
27 std::ifstream fs(filename_.c_str());
28 int pid;
29 bool good;
30
31 // If we weren't able to open the file treat
32 // it as if the process wasn't running
33 if (!fs.is_open()) {
34 return (false);
35 }
36
37 // Try to get the pid, get the status and get rid of the file
38 fs >> pid;
39 good = fs.good();
40 fs.close();
41
42 // If we weren't able to read a pid send back an exception
43 if (!good) {
44 isc_throw(PIDCantReadPID, "Unable to read PID from file '"
45 << filename_ << "'");
46 }
47
48 // If the process is still running return its pid.
49 if (kill(pid, 0) == 0) {
50 return (pid);
51 }
52
53 // No process
54 return (0);
55}
56
57void
59 write(getpid());
60}
61
62void
63PIDFile::write(int pid) const {
64 std::ofstream fs(filename_.c_str(), std::ofstream::trunc);
65
66 if (!fs.is_open()) {
67 isc_throw(PIDFileError, "Unable to open PID file '"
68 << filename_ << "' for write");
69 }
70
71 // File is open, write the pid.
72 fs << pid << std::endl;
73
74 bool good = fs.good();
75 fs.close();
76
77 if (!good) {
78 isc_throw(PIDFileError, "Unable to write to PID file '"
79 << filename_ << "'");
80 }
81}
82
83void
85 if ((remove(filename_.c_str()) != 0) &&
86 (errno != ENOENT)) {
87 isc_throw(PIDFileError, "Unable to delete PID file '"
88 << filename_ << "'");
89 }
90}
91
92} // namespace isc::util
93} // namespace isc
Exception thrown when an error occurs trying to read a PID from an opened file.
Definition pid_file.h:28
Exception thrown when an error occurs during PID file processing.
Definition pid_file.h:20
PIDFile(const std::string &filename)
Constructor.
Definition pid_file.cc:18
~PIDFile()
Destructor.
Definition pid_file.cc:22
void write() const
Get PID of the current process and write it to the file.
Definition pid_file.cc:58
void deleteFile() const
Delete the PID file.
Definition pid_file.cc:84
int check() const
Read the PID in from the file and check it.
Definition pid_file.cc:26
#define isc_throw(type, stream)
A shortcut macro to insert known values into exception arguments.
Defines the logger used by the top-level component of kea-lfc.