// support.cc
// Non-class support functions for gdisk program.
// Primarily by Rod Smith, February 2009, but with a few functions
// copied from other sources (see attributions below).
/* This program is copyright (c) 2009-2013 by Roderick W. Smith. It is distributed
under the terms of the GNU GPL version 2, as detailed in the COPYING file. */
#define __STDC_LIMIT_MACROS
#ifndef __STDC_CONSTANT_MACROS
#define __STDC_CONSTANT_MACROS
#endif
#include <stdio.h>
#include <stdint.h>
#include <errno.h>
#include <fcntl.h>
#include <string.h>
#include <sys/stat.h>
#include <string>
#include <iostream>
#include <sstream>
#include "support.h"
#include <sys/types.h>
// As of 1/2010, BLKPBSZGET is very new, so I'm explicitly defining it if
// it's not already defined. This should become unnecessary in the future.
// Note that this is a Linux-only ioctl....
#ifndef BLKPBSZGET
#define BLKPBSZGET _IO(0x12,123)
#endif
using namespace std;
// Reads a string from stdin, returning it as a C++-style string.
// Note that the returned string will NOT include the carriage return
// entered by the user.
string ReadString(void) {
string inString;
getline(cin, inString);
if (!cin.good())
exit(5);
return inString;
} // ReadString()
// Get a numeric value from the user, between low and high (inclusive).
// Keeps looping until the user enters a value within that range.
// If user provides no input, def (default value) is returned.
// (If def is outside of the low-high range, an explicit response
// is required.)
int GetNumber(int low, int high, int def, const string & prompt) {
int response, num;
char line[255];
if (low != high) { // bother only if low and high differ...
do {
cout << prompt;
cin.getline(line, 255);
if (!cin.good())
exit(5);
num = sscanf(line, "%d", &response);
if (num == 1) { // user provided a response
if ((response < low) || (response > high))
cout << "Value out of range\n";
} else { // user hit enter; return default
response = def;
} // if/else
} while ((response < low) || (response > high));
} else { // low == high, so return this value
cout << "Using " << low << "\n";
response = low;
} // else
return (response);
} // GetNumber()
// Gets a Y/N response (and converts lowercase to uppercase)
char GetYN(void) {
char response;
string line;
bool again = 0 ;
do {
if ( again ) { cout << "Your option? " ; }
again = 1 ;
cout << "(Y/N): ";
line = ReadString();
response = toupper(line[0]);
} while ((response != 'Y') && (response != 'N'));
return response;
} // GetYN(void)
// Obtains a sector number, between low and high, from the
// user, accepting values prefixed by "+" to add sectors to low,
// or the same with "K", "M", "G", "T", or "P" as suffixes to add
// kilobytes, megabytes, gigabytes, terabytes, or petabytes,
// respectively. If a "-" prefix is used, use the high value minus
// the user-specified number of sectors (or KiB, MiB, etc.). Use the
// def value as the default if the user just hits Enter. The sSize is
// the sector size of the device.
uint64_t GetSectorNum(uint64_t low, uint64_t high, uint64_t def, uint64_t sSize,
const string & prompt) {
uint64_t response;
char line[255];
do {
cout << prompt;
cin.getline(line, 255);
if (!cin.good())
exit(5);
response = IeeeToInt(line, sSize, low, high, def);
} while ((response < low) || (response > high));
return response;
} // GetSectorNum()
// Convert an IEEE-1541-2002 value (K, M, G, T, P, or E) to its equivalent in
// number of sectors. If no units are appended, interprets as the number
// of sectors; otherwise, interprets as number of specified units and
// converts to sectors. For instance, with 512-byte sectors, "1K" converts
// to 2. If value includes a "+", adds low and subtracts 1; if SIValue
// inclues a "-", subtracts from high. If IeeeValue is empty, returns def.
// Returns final sector value. In case inValue is invalid, returns 0 (a
// sector value that's always in use on GPT and therefore invalid); and if
// inValue works out to something outside the range low-high, returns the
// computed value; the calling function is responsible for checking the
// validity of this value.
// NOTE: There's a difference in how GCC and VC++ treat oversized values
// (say, "999999999999999999999") read via the ">>" operator; GCC turns
// them into the maximum value for the type, whereas VC++ turns them into
// 0 values. The result is that IeeeToInt() returns UINT64_MAX when
// compiled with GCC (and so the value is rejected), whereas when VC++
// is used, the default value is returned.
uint64_t IeeeToInt(string inValue, uint64_t sSize, uint64_t low, uint64_t high, uint64_t def) {
uint64_t response = def, bytesPerUnit = 1, mult = 1, divide = 1;
size_t foundAt = 0;
char suffix, plusFlag = ' ';
string suffixes = "KMGTPE";
int badInput = 0; // flag bad input; once this goes to 1, other values are irrelevant
if (sSize == 0) {
sSize = SECTOR_SIZE;
cerr << "Bug: Sector size invalid in IeeeToInt()!\n";
} // if
// Remove leading spaces, if present
while (inValue[0] == ' ')
inValue.erase(0, 1);
// If present, flag and remove leading plus or minus sign
if ((inValue[0] == '+') || (inValue[0] == '-')) {
plusFlag = inValue[0];
inValue.erase(0, 1);
} // if
// Extract numeric response and, if present, suffix
istringstream inString(inValue);
if (((inString.peek() < '0') || (inString.peek() > '9')) && (inString.peek() != -1))
badInput = 1;
inString >> response >> suffix;
suffix = toupper(suffix);
// If no response, or if response == 0, use default (def)
if ((inValue.length() == 0) || (response == 0)) {
response = def;
suffix = ' ';
plusFlag = ' ';
} // if
// Find multiplication and division factors for the suffix
foundAt = suffixes.find(suffix);
if (foundAt != string::npos) {
bytesPerUnit = UINT64_C(1) << (10 * (foundAt + 1));
mult = bytesPerUnit / sSize;
divide = sSize / bytesPerUnit;
} // if
// Adjust response based on multiplier and plus flag, if present
if (mult > 1) {
if (response > (UINT64_MAX / mult))
badInput = 1;
else
response *= mult;
} else if (divide > 1) {
response /= divide;
} // if/elseif
if (plusFlag == '+') {
// Recompute response based on low part of range (if default == high
// value, which should be the case when prompting for the end of a
// range) or the defaut value (if default != high, which should be
// the case for the first sector of a partition).
if (def == high) {
if (response > 0)
response--;
if (response > (UINT64_MAX - low))
badInput = 1;
else
response = response + low;
} else {
if (response > (UINT64_MAX - def))
badInput = 1;
else
response = response + def;
} // if/else
} else if (plusFlag == '-') {
if (response > high)
badInput = 1;
else
response = high - response;
} // if
if (badInput)
response = UINT64_C(0);
return response;
} // IeeeToInt()
// Takes a size and converts this to a size in IEEE-1541-2002 units (KiB, MiB,
// GiB, TiB, PiB, or EiB), returned in C++ string form. The size is either in
// units of the sector size or, if that parameter is omitted, in bytes.
// (sectorSize defaults to 1). Note that this function uses peculiar
// manual computation of decimal value rather than simply setting
// theValue.precision() because this isn't possible using the available
// EFI library.
string BytesToIeee(uint64_t size, uint32_t sectorSize) {
uint64_t sizeInIeee;
uint64_t previousIeee;
float decimalIeee;
uint index = 0;
string units, prefixes = " KMGTPEZ";
ostringstream theValue;
sizeInIeee = previousIeee = size * (uint64_t) sectorSize;
while ((sizeInIeee > 1024) && (index < (prefixes.length() - 1))) {
index++;
previousIeee = sizeInIeee;
sizeInIeee /= 1024;
} // while
if (prefixes[index] == ' ') {
theValue << sizeInIeee << " bytes";
} else {
units = " iB";
units[1] = prefixes[index];
decimalIeee = ((float) previousIeee -
((float) sizeInIeee * 1024.0) + 51.2) / 102.4;
if (decimalIeee >= 10.0) {
decimalIeee = 0.0;
sizeInIeee++;
}
theValue << sizeInIeee << "." << (uint32_t) decimalIeee << units;
} // if/else
return theValue.str();
} // BytesToIeee()
// Converts two consecutive characters in the input string into a
// number, interpreting the string as a hexadecimal number, starting
// at the specified position.
unsigned char StrToHex(const string & input, unsigned int position) {
unsigned char retval = 0x00;
unsigned int temp;
if (input.length() > position) {
sscanf(input.substr(position, 2).c_str(), "%x", &temp);
retval = (unsigned char) temp;
} // if
return retval;
} // StrToHex()
// Returns 1 if input can be interpreted as a hexadecimal number --
// all characters must be spaces, digits, or letters A-F (upper- or
// lower-case), with at least one valid hexadecimal digit; with the
// exception of the first two characters, which may be "0x"; otherwise
// returns 0.
int IsHex(string input) {
int isHex = 1, foundHex = 0, i;
if (input.substr(0, 2) == "0x")
input.erase(0, 2);
for (i = 0; i < (int) input.length(); i++) {
if ((input[i] < '0') || (input[i] > '9')) {
if ((input[i] < 'A') || (input[i] > 'F')) {
if ((input[i] < 'a') || (input[i] > 'f')) {
if ((input[i] != ' ') && (input[i] != '\n')) {
isHex = 0;
}
} else foundHex = 1;
} else foundHex = 1;
} else foundHex = 1;
} // for
if (!foundHex)
isHex = 0;
return isHex;
} // IsHex()
// Return 1 if the CPU architecture is little endian, 0 if it's big endian....
int IsLittleEndian(void) {
int littleE = 1; // assume little-endian (Intel-style)
union {
uint32_t num;
unsigned char uc[sizeof(uint32_t)];
} endian;
endian.num = 1;
if (endian.uc[0] != (unsigned char) 1) {
littleE = 0;
} // if
return (littleE);
} // IsLittleEndian()
// Reverse the byte order of theValue; numBytes is number of bytes
void ReverseBytes(void* theValue, int numBytes) {
char* tempValue = NULL;
int i;
tempValue = new char [numBytes];
if (tempValue != NULL) {
memcpy(tempValue, theValue, numBytes);
for (i = 0; i < numBytes; i++)
((char*) theValue)[i] = tempValue[numBytes - i - 1];
delete[] tempValue;
} else {
cerr << "Could not allocate memory in ReverseBytes()! Terminating\n";
exit(1);
} // if/else
} // ReverseBytes()
// On Windows, display a warning and ask whether to continue. If the user elects
// not to continue, exit immediately.
void WinWarning(void) {
#ifdef _WIN32
cout << "\a************************************************************************\n"
<< "Most versions of Windows cannot boot from a GPT disk except on a UEFI-based\n"
<< "computer, and most varieties prior to Vista cannot read GPT disks. Therefore,\n"
<< "you should exit now unless you understand the implications of converting MBR\n"
<< "to GPT or creating a new GPT disk layout!\n"
<< "************************************************************************\n\n";
cout << "Are you SURE you want to continue? ";
if (GetYN() != 'Y')
exit(0);
#endif
} // WinWarning()