Linux 判断进程是否已经运行的程序

 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   }