sgdisk.cc

// sgdisk.cc
// Command-line-based version of gdisk. This program is named after sfdisk,
// and it can serve a similar role (easily scripted, etc.), but it's used
// strictly via command-line arguments, and it doesn't bear much resemblance
// to sfdisk in actual use.
//
// by Rod Smith, project began February 2009; sgdisk begun January 2010.

/* This program is copyright (c) 2009-2011 by Roderick W. Smith. It is distributed
  under the terms of the GNU GPL version 2, as detailed in the COPYING file. */

#include <iostream>
#include <fstream>
#include <string.h>
#include <string>
#include <iostream>
#include <sstream>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>

#include "sgdisk.h"
#include "gptcl.h"

using namespace std;

#define MAX_OPTIONS 50

int sgdisk_read(const char* device, sgdisk_partition_table& ptbl,
                vector<sgdisk_partition>& partitions) {
    BasicMBRData mbrData;
    GPTData gptData;
    GPTPart partData;
    int numParts = 0;

    /* Silence noisy underlying library */
    int stdout_fd = dup(STDOUT_FILENO);
    int stderr_fd = dup(STDERR_FILENO);
    int silence = open("/dev/null", 0);
    dup2(silence, STDOUT_FILENO);
    dup2(silence, STDERR_FILENO);

    if (!mbrData.ReadMBRData((string) device)) {
        cerr << "Failed to read MBR" << endl;
        return 8;
    }

    switch (mbrData.GetValidity()) {
    case mbr:
        ptbl.type = MBR;
        ptbl.guid.clear();
        for (size_t i = 0; i < MAX_MBR_PARTS; i++) {
            if (mbrData.GetLength(i) > 0) {
                char typebuf[2+8+1];
                sprintf(typebuf, "%x", (unsigned int)mbrData.GetType(i));
                sgdisk_partition part;
                part.num = i + 1;
                part.type = typebuf;
                partitions.push_back(part);
            }
        }
        break;
    case hybrid:
    case gpt:
        gptData.JustLooking();
        if (!gptData.LoadPartitions((string) device)) {
            cerr << "Failed to read GPT" << endl;
            return 9;
        }

        ptbl.type = GPT;
        ptbl.guid = gptData.GetDiskGUID().AsString();
        for (size_t i = 0; i < gptData.GetNumParts(); i++) {
            partData = gptData[i];
            if (partData.GetFirstLBA() > 0) {
                sgdisk_partition part;
                part.num = i + 1;
                part.type = partData.GetType().AsString();
                part.guid = partData.GetUniqueGUID().AsString();
                part.name = partData.GetDescription();
                partitions.push_back(part);
            }
        }
        break;
    default:
        cerr << "Unknown partition table" << endl;
        return 10;
    }

    fflush(stdout);
    fflush(stderr);
    dup2(stdout_fd, STDOUT_FILENO);
    dup2(stderr_fd, STDERR_FILENO);
    close(silence);

    return 0;
}

/*
 * Dump partition details in a machine readable format:
 *
 * DISK [mbr|gpt] [guid]
 * PART [n] [type] [guid]
 */
static int android_dump(const char* device) {
    sgdisk_partition_table ptbl;
    vector<sgdisk_partition> partitions;
    int rc = sgdisk_read(device, ptbl, partitions);
    if (rc == 0) {
        stringstream res;
        switch (ptbl.type) {
        case MBR:
            res << "DISK mbr" << endl;
            for (auto& part : partitions) {
                res << "PART " << part.num << " " << part.type << endl;
            }
            break;
        case GPT:
            res << "DISK gpt " << ptbl.guid << endl;
            for (auto& part : partitions) {
                res << "PART " << part.num << " " << part.type << " "
                    << part.guid << " " << part.name << endl;
            }
            break;
        default:
            return 10;
        }
        string partStr = res.str();
        write(STDOUT_FILENO, partStr.c_str(), partStr.length());
    }
    return rc;
}

extern "C" int main(int argc, char *argv[]) {
    for (int i = 0; i < argc; i++) {
        if (!strcmp("--android-dump", argv[i])) {
            return android_dump(argv[i + 1]);
        }
    }

    GPTDataCL theGPT;
    return theGPT.DoOptions(argc, argv);
}