copying large files in c/c++ under FreeBSD freezes system - c++

Question

this code seems to work under Windows (with unexpected results) and Ubuntu. But when I run it under FreeBSD 9.0 AMD 64 it causes the system to freeze. I get error messages like this:
ahcich0: Timeout on slot 28 port 0
Does anybody know what the problem could be?
Thanks.
#include <cmath>
#include <cstdlib>
#include <sys/time.h>
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
int main(int argc, char *argv[])
{
const string FILENAME = "testfile";
const string COPYNAME = "copy";
const int FILES = 5;
const int SIZE_MULTIPLIER = 6;
const int BUFFER_SIZE = pow(2.0, 16);
time_t times[2][FILES];
srand (time(NULL));
// create test files
for (int i = 1; i < FILES + 1; i++){
ofstream os;
string filename(FILENAME);
filename += (char)i + 48;
os.open(filename.c_str(), ios::binary);
if (os.is_open()){
cout << "Writing file " << i << " of " << FILES;
long filesize =pow(2.0, i * SIZE_MULTIPLIER);
cout << " (" << filesize << " bytes)" << endl;
while(filesize--){
os << (char)(rand() % 256);
}
cout << os.tellp() << " bytes written.\n";
os.close();
}else{
cerr << "Could not create file " << filename;
cerr << endl;
}
}
// copy the files
timeval tv;
time_t start;
char buffer[BUFFER_SIZE];
char ci;
for (int i = 0; i < FILES; i++){
ci = (char)i + 49;
string filename(FILENAME);
filename += ci;
string copyname("c");
copyname += COPYNAME;
copyname += ci;
cout << "Copying file " << filename.c_str() << endl;
cout << "the c way: ";
cout.flush();
start = time(NULL);
FILE *pFile = fopen(filename.c_str(), "rb");
FILE *pCopy = fopen(copyname.c_str(), "wb");
if (!(pFile == NULL || pCopy == NULL)){
do{
int bytesRead = fread(
buffer, 1, BUFFER_SIZE, pFile);
fwrite(buffer, 1, bytesRead, pCopy);
}while(!feof(pFile));
fclose(pFile);
fclose(pCopy);
cout << " Done.\n";
}else{
cerr << "Could not open either " << filename;
cerr << " or " << copyname << endl;
}
times[0][i] = time(NULL) - start;
remove(copyname.c_str());
copyname = "cpp";
copyname += COPYNAME;
copyname += ci;
cout << "the c++ way: ";
cout.flush();
start = time(NULL);
ifstream in;
in.open(filename.c_str(), ios::binary);
in.rdbuf()->pubsetbuf(buffer, BUFFER_SIZE);
ofstream out;
out.open(copyname.c_str(), ios::binary);
char copyBuffer[BUFFER_SIZE];
out.rdbuf()->pubsetbuf(copyBuffer, BUFFER_SIZE);
if (in.is_open() && out.is_open()){
out << in.rdbuf();
in.close();
out.close();
cout << " Done.\n";
}else{
cerr << "Could not open either " << filename;
cerr << " or " << copyname << endl;
}
times[1][i] = time(NULL) - start ;
remove(copyname.c_str());
}
cout << "Summary:\n";
cout << "\tc\tc++\n";
for (int i = 0; i < FILES; i++){
ci = (char)i + 49;
cout << "copy" << ci << "\t" << times[0][i];
cout << "\t" << times[1][i] << endl;
}
return 0;
}

Answer 1

After changing FILES to 4 (because it takes very long otherwise), your program ran just fine here:
Writing file 1 of 4 (64 bytes)
64 bytes written.
Writing file 2 of 4 (4096 bytes)
4096 bytes written.
Writing file 3 of 4 (262144 bytes)
262144 bytes written.
Writing file 4 of 4 (16777216 bytes)
16777216 bytes written.
Copying file testfile1
the c way: Done.
the c++ way: Done.
Copying file testfile2
the c way: Done.
the c++ way: Done.
Copying file testfile3
the c way: Done.
the c++ way: Done.
Copying file testfile4
the c way: Done.
the c++ way: Done.
Summary:
c c++
copy1 0 0
copy2 0 0
copy3 0 0
copy4 0 0
(FreeBSD 9.0-RELEASE-p3 amd64, compiled with clang++)

Answer 2

There could've been a bug in the achi-driver in 9.0, that showed up under heavy load. Or, it could've been a buggy controller, that was failing under the same load -- and not failing under other OSes, because they weren't taxing it as much.
Is this still a problem with FreeBSD 9.2?
As for your program, you ought to check not just for feof(), but also for ferror() in your read/write loop. Further, in my opinion, such read/write loops are a thing from the past. These days, when size_t and offset_t are of the same width (64-bit platforms), you ought to simply mmap() your source file and fwrite it into destination in one go. Look, ma, no loop!