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ProcStats.cpp

Go to the documentation of this file.

// Class: ProcStats
// Purpose:  To keep statistics on memory use
// Warning:  Only Linux implementation at the present time...

#include "ProcStats.h"

#ifdef linux
#include <unistd.h>
#include <iostream>
//#include <sstream>
#include <strstream>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/signal.h>
#include <sys/syscall.h>
#include <sys/procfs.h>
#include <cstdio>

using std::cerr;
using std::cout;
using std::endl;

struct linux_proc {
        int pid; // %d
        char comm[400]; // %s
        char state; // %c
        int ppid; // %d
        int pgrp; // %d
        int session; // %d
        int tty; // %d
        int tpgid; // %d
        unsigned int flags; // %u
        unsigned int minflt; // %u
        unsigned int cminflt; // %u
        unsigned int majflt; // %u
        unsigned int cmajflt; // %u
        int utime; // %d
        int stime; // %d
        int cutime; // %d
        int cstime; // %d
        int counter; // %d
        int priority; // %d
        unsigned int timeout; // %u
        unsigned int itrealvalue; // %u
        int starttime; // %d
        unsigned int vsize; // %u
        unsigned int rss; // %u
        unsigned int rlim; // %u
        unsigned int startcode; // %u
        unsigned int endcode; // %u
        unsigned int startstack; // %u
        unsigned int kstkesp; // %u
        unsigned int kstkeip; // %u
        int signal; // %d
        int blocked; // %d
        int sigignore; // %d
        int sigcatch; // %d
        unsigned int wchan; // %u
};
#endif // linux

ProcStats::cleanup::~cleanup()
        {
                if(ProcStats::inst!=0)
                {
                        delete ProcStats::inst;
                        ProcStats::inst=0;
                }
        }

ProcStats* ProcStats::instance()
{
        static cleanup c;
        if(inst==0)
                inst = new ProcStats;
        return inst;
}

ProcStats* ProcStats::inst = 0;

ProcStats::ProcStats():valid(false)
{
#ifdef linux
        pg_size = sysconf(_SC_PAGESIZE); // getpagesize();

  // The following 3 lines are needed because no ostrinstream exists in gcc
  const int stbuffer_size = 1024;  
  char stbuffer[ stbuffer_size ] = { 0 , 0 }; 
  std::ostrstream ost(stbuffer, stbuffer_size); 

  ost << "/proc/" << getpid() << "/stat";
  fname = ost.str();
  if((fd=open(fname.c_str(),O_RDONLY))<0)
  {
    cerr << "Failed to open " << ost.str() << endl;
    return;
  }
#endif
        valid=true;
}

ProcStats::~ProcStats()
{
#ifdef linux
  close(fd);
#endif
}

bool ProcStats::fetch(procInfo& f)
{
        if(valid==false) return false;

#ifdef linux
        double pr_size, pr_rssize;
        linux_proc pinfo;
        int cnt;

  lseek(fd,0,SEEK_SET);

        if((cnt=read(fd,buf,sizeof(buf)))<0)
        {
          cout << "LINUX Read of Proc file failed:" << endl;
          return false;
        }

        if(cnt>0)
        {
                buf[cnt]='\0';

                sscanf(buf,
                        "%d %s %c %d %d %d %d %d %u %u %u %u %u %d %d %d %d %d %d %u %u %d %u %u %u %u %u %u %u %u %d %d %d %d %u",
                        &pinfo.pid, // %d
                        pinfo.comm, // %s
                        &pinfo.state, // %c
                        &pinfo.ppid, // %d
                        &pinfo.pgrp, // %d
                        &pinfo.session, // %d
                        &pinfo.tty, // %d
                        &pinfo.tpgid, // %d
                        &pinfo.flags, // %u
                        &pinfo.minflt, // %u
                        &pinfo.cminflt, // %u
                        &pinfo.majflt, // %u
                        &pinfo.cmajflt, // %u
                        &pinfo.utime, // %d
                        &pinfo.stime, // %d
                        &pinfo.cutime, // %d
                        &pinfo.cstime, // %d
                        &pinfo.counter, // %d
                        &pinfo.priority, // %d
                        &pinfo.timeout, // %u
                        &pinfo.itrealvalue, // %u
                        &pinfo.starttime, // %d
                        &pinfo.vsize, // %u
                        &pinfo.rss, // %u
                        &pinfo.rlim, // %u
                        &pinfo.startcode, // %u
                        &pinfo.endcode, // %u
                        &pinfo.startstack, // %u
                        &pinfo.kstkesp, // %u
                        &pinfo.kstkeip, // %u
                        &pinfo.signal, // %d
                        &pinfo.blocked, // %d
                        &pinfo.sigignore, // %d
                        &pinfo.sigcatch, // %d
                        &pinfo.wchan // %u
                        );

        // resident set size in pages
                pr_size = (double)pinfo.vsize;
                pr_rssize = (double)pinfo.rss;

                f.vsize = pr_size   / 1000000.0;
                f.rss   = pr_rssize * pg_size / 1000000.0;
  }

#else
  f.vsize = 0;
  f.rss   = 0;
#endif

        bool rc = (curr==f)?false:true;

        curr.rss=f.rss;
        curr.vsize=f.vsize;

        return rc;
}

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