Seg Fault - Signal received, SIGABORT - c++

Question

So my code compiles well, but whenever I try running the program, it seg faults. I ran it through gdb and got this set of error:
terminate called after throwing an instance of 'std::logic_error'
what(): basic_string::_S_construct null not valid
Program received signal SIGABRT, Aborted.
0x00007ffff722bcc9 in __GI_raise (sig=sig#entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
56 ../nptl/sysdeps/unix/sysv/linux/raise.c: No such file or directory.
Here is my code if it helps:
using namespace std;
#include <iostream>
#include <vector>
#include <cmath>
#include<fstream>
#include <cstdlib>
#include <utility>
#include <string>
class Page
{
public:
int TimeStamp;
int ProgramOwner;
int LocalPageNumber;
};
//Pair: first entry is local page, second entry is global page
//Second entry: 1 if in main memory, 0 if not
class Program
{
public:
vector< pair<int,int> > MemoryMap;
};
class Memory
{
public:
vector<Program> Programs;
vector<Page> Pages;
};
void checkArguments(int argc, char *argv[]);
bool checkPageAlgorithm(char *argv[]);
bool checkPageSize(int pagesize);
bool checkPageStyle(char *argv[]);
bool checkPTrace(string ProgramTraceFile);
bool checkPList(string ProgramListFile);
int main(int argc, char *argv[])
{
//checkArguments(argc, argv);
const int MemSize = 512;
int pageSize = atoi(argv[3]);
string programListFile = argv[1];
string ProgramTraceFile = argv[2];
string pageAlgorithm = argv[4];
string pageStyle = argv[5];
int programNumber;
int programSize;
int PagesNeeded;
Memory MainMemory;
int numberFrames;
int pageFaults = 0;
int numPrograms = 0;
int PagesPerProgram;
int LocalPage;
int activeProgram;
int requestedLocation;
int newPageLocation;
bool foundInMemory;
ifstream fileIn;
fileIn.open(programListFile.c_str());
if(fileIn.fail())
{
cerr << "List file not found." << endl;
fileIn.close();
exit(1);
}
else
{
while(!fileIn.eof())
{
cout << "hey0";
fileIn >> programNumber;
fileIn >> programSize;
numPrograms++;
}
}
numberFrames = ceil(MemSize/pageSize);
PagesPerProgram = ceil(numberFrames/numPrograms);
MainMemory.Pages.resize(numberFrames);
cout << "hey1";
while(!fileIn.eof())
{
cout << "hey2";
fileIn >> programNumber;
fileIn >> programSize;
cout << "hey3";
PagesNeeded = ceil(programSize/pageSize);
for(int i = 0; i < PagesNeeded; i++)
{
LocalPage = i;
MainMemory.Pages[i].ProgramOwner = programNumber;
MainMemory.Pages[i].LocalPageNumber = LocalPage;
}
cout << "hey3";
if(PagesNeeded > PagesPerProgram)
PagesNeeded = PagesPerProgram;
for(int i = 0; i < PagesNeeded; i++)
{
MainMemory.Programs[programNumber].MemoryMap[i].first = MainMemory.Pages[i].LocalPageNumber;
MainMemory.Programs[programNumber].MemoryMap[i].second = 1;
if(pageAlgorithm == "clock")
MainMemory.Pages[i].TimeStamp = 1;
else
MainMemory.Pages[i].TimeStamp = 0;
}
}
fileIn.close();
//LRU Algorithm Implementation
if(pageAlgorithm == "lru")
{
cout << "here1";
fileIn.open(ProgramTraceFile.c_str());
if(fileIn.fail())
{
cerr << "That file does not exist." << endl;
fileIn.close();
exit(1);
}
else
{
fileIn >> activeProgram;
fileIn >> requestedLocation;
newPageLocation = ceil(requestedLocation/pageSize);
while(!fileIn.eof())
{
foundInMemory = false;
for(int i = 0; i < static_cast<int>(MainMemory.Programs[activeProgram].MemoryMap.size()); i++)
{
if((MainMemory.Programs[activeProgram].MemoryMap[i].second == 1) &&
(MainMemory.Programs[activeProgram].MemoryMap[i].first == newPageLocation))
foundInMemory = true;
if(foundInMemory)
break;
}
if(!foundInMemory)
{
pageFaults++;
if(static_cast<int>(MainMemory.Programs[activeProgram].MemoryMap.size()) < PagesPerProgram)
{
pair<int, int> temp;
temp.first = newPageLocation;
temp.second = 1;
MainMemory.Programs[activeProgram].MemoryMap.push_back(temp);
}
else
{
for(int i = 0; i < (static_cast<int>(MainMemory.Programs[activeProgram].MemoryMap.size()) - 1); i++)
{
if(MainMemory.Pages[i].TimeStamp >= MainMemory.Pages[i+1].TimeStamp)
{
MainMemory.Programs[activeProgram].MemoryMap[i].first = newPageLocation;
}
if(pageStyle == "1")
{
if(MainMemory.Pages[i].TimeStamp >= MainMemory.Pages[i+1].TimeStamp)
{
MainMemory.Programs[activeProgram].MemoryMap[i].first = MainMemory.Pages[i].LocalPageNumber;
}
}
MainMemory.Pages[i].TimeStamp++;
}
}
}
fileIn >> activeProgram;
fileIn >> requestedLocation;
newPageLocation = ceil(requestedLocation/pageSize);
}
}
}
cout << "------------------------------------" << endl;
cout << "Page Size: " << pageSize << endl;
cout << "Page Replacement Algorithm: " << pageAlgorithm << endl;
cout << "Paging Style: ";
if(pageStyle == "0")
cout << "Demand" << endl;
else
cout << "Prepaging" << endl;
cout << "Number of Page Faults: " << pageFaults << endl;
cout << "------------------------------------" << endl;
return 0;
}
bool checkPList(string programlistfile)
{
ifstream ListFile(programlistfile.c_str());
if(ListFile.fail())
{
cerr << "Cannot find file " << programlistfile << endl;
ListFile.close();
return false;
}
else
{
ListFile.close();
return true;
}
}
bool checkPTrace(string programTraceFile)
{
ifstream TraceFile;
TraceFile.open(programTraceFile.c_str());
if(TraceFile.fail())
{
cerr << "Cannot find file " << programTraceFile << endl;
TraceFile.close();
return false;
}
else
{
TraceFile.close();
return true;
}
}
bool checkPageStyle(string pageStyle)
{
if(pageStyle == "0")
return true;
else if(pageStyle == "1")
return true;
else
{
cerr << "Page Style can be: 0 or 1." << endl;
return false;
}
}
bool checkPageSize(int pagesize)
{
bool isValid = false;
switch(pagesize)
{
case 1:
isValid = true;
break;
case 2:
isValid = true;
break;
case 4:
isValid = true;
break;
case 8:
isValid = true;
break;
case 16:
isValid = true;
break;
default:
cerr << "Page Size can be: 1, 2, 4, 8, or 16." << endl;
isValid = false;
}
return isValid;
}
bool checkPageAlgorithm(string pageAlgorithm)
{
if(pageAlgorithm == "lru")
return true;
else if(pageAlgorithm == "fifo")
return true;
else if(pageAlgorithm == "clock")
return true;
else
{
cerr << "Valid Page Algorithms are: lru, fifo, or clock" << endl;
return false;
}
}
void checkArguments(int argc, char *argv[])
{
if(argc < 6)
{
cerr << "Invalid number of arguments. Should be: programlist programtrace pagesize pagealgorithm pagingstyle" << endl;
exit(1);
}
else if(argc > 6)
{
cerr << "Invalid number of arguments. Should be: programlist programtrace pagesize pagealgorithm pagingstyle" << endl;
exit(1);
}
else if(!checkPageAlgorithm(argv[4]))
exit(1);
else if(!checkPageSize(atoi(argv[3])))
exit(1);
else if(!checkPageStyle(argv[5]))
exit(1);
else if(!checkPTrace(argv[2]))
exit(1);
else if(!checkPList(argv[1]))
exit(1);
return;
}
The output 'heys' are just to see if they get triggered within gdb, which they don't.

Answer 1

You forgot to actually ask any question.
Presumably, your question is "why does my program die with SIGABRT?"
The answer was provided by the program itself: you've tried to construct std::string from a NULL character pointer, which throws std::logic_error exception (because it's not a valid thing to do).
You may have a follow-up quesiton: "where in my program does this happen?".
You could find the answer by using GDB where command. As a first guess, you didn't invoke your program with sufficient number of arguments. For example, if you did this:
gdb ./a.out
(gdb) run
then argv[1] is NULL, and this statement:
string programListFile = argv[1];
would throw the exception you are getting.
The common solution to this problem is to insist that you do have correct number of arguments, e.g. put this:
if (argc < 6) {
std::cerr << "Not enough arguments" << std::endl;
return 1;
}
at the start of main. Or just comment the call to checkArguments() back in.