1 bool
2 ServerProcess::isAlreadyRunning()
3 {
4 #ifndef __linux__
5 WarningLog(<<"can't check if process already running on this platform (not implemented yet)");
6 return false;
7 #else
8 if(mPidFile.size() == 0)
9 {
10 // if no PID file specified, we do not make any check
11 return false;
12 }
13
14 pid_t running_pid;
15 std::ifstream _pid(mPidFile.c_str(), std::ios_base::in);
16 if(!_pid.good())
17 {
18 // if the file doesn't exist or can't be opened, just ignore
19 return false;
20 }
21 _pid >> running_pid;
22 _pid.close();
23
24 StackLog(<< mPidFile << " contains PID " << running_pid);
25
26 Data ourProc = Data("/proc/self/exe");
27 Data otherProc = Data("/proc/") + Data(running_pid) + Data("/exe");
28 char our_exe[513], other_exe[513];
29 int buf_size;
30
31 buf_size = readlink(ourProc.c_str(), our_exe, 512);
32 if(buf_size < 0 || buf_size == 512)
33 {
34 // if readlink fails, just ignore
35 return false;
36 }
37 our_exe[buf_size] = 0;
38
39 buf_size = readlink(otherProc.c_str(), other_exe, 512);
40 if(buf_size < 0 || buf_size == 512)
41 {
42 // if readlink fails, just ignore
43 return false;
44 }
45 other_exe[buf_size] = 0;
46
47 if(strcmp(our_exe, other_exe) == 0)
48 {
49 ErrLog(<<"already running PID: " << running_pid);
50 return true;
51 }
52 return false;
53 #endif
54 }
