Reading Hard Disk Sectors in C++ on Linux

Question

How do you read hard disk sectors in C++ with gcc/linux? Is there a standard library that I can use or must something be downloaded? In Windows I can use CreateFile(...) to acce

Answer 1

As others have correctly pointed out, disk access on Linux (and other Unix-like operating systems) is via a device special file. On my Ubuntu laptop, my hard drive is named "/dev/sda".

Since you specifically ask how to do it in C++ (not merely how to do it in Linux), here is how to read one sector using std::ifstream.

#include 
#include 
#include 
#include 
#include 

int main() {
  // Which disk?
  char diskName[] = "/dev/sda";
  std::string diskError = std::string() + diskName + ": ";

  // Open device file
  std::ifstream disk(diskName, std::ios_base::binary);

  if(!disk)
    throw(std::runtime_error(diskError + std::strerror(errno)));

  // Seek to 54321'th sector
  disk.seekg(512 * 54321);
  if(!disk)
    throw(std::runtime_error(diskError + std::strerror(errno)));

  // Read in one sector
  std::vector buffer(512);
  disk.read(&buffer[0], 512);
  if(!disk)
    throw(std::runtime_error(diskError + std::strerror(errno)));
}