ssn-installer/src/parseArguments.c

#include <getopt.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "decrypt.h"
#include "errorAndExit.h"
#include "parseArguments.h"
#include "rateLimiter.h"

//Uses GNU's getopt_long_only(), see https://www.gnu.org/software/libc/manual/html_node/Getopt-Long-Options.html

//For a description of these arguments, see errorAndExit.c
static struct option long_options[] = {
  {"disk", required_argument, 0, 'd'},
  {"offset", required_argument, 0, 'o'},
  {"size", required_argument, 0, 's'},
  {"keys", required_argument, 0, 'k'},
  {"previous", required_argument, 0, 'p'},
  {"target", required_argument, 0, 't'},
  {"limit", required_argument, 0, 'l'},
  {NULL, 0, 0, 0},
};


struct arguments parseArguments(int argc, char *argv[]) {
  //Stores current state from command line arguments, initialized to zero
  struct arguments state = {};

  bool hasDisk = false;
  bool hasOffset = false;
  bool hasSize = false;

  while (1) {
    //In this variable, getopt_long stores the current long option that was found. Unused since we don't use flags in our long options
    int optionIndex = 0;

    int curOption = getopt_long_only(argc, argv, "", long_options, &optionIndex);

    //end of command line arguments reached
    if (curOption == -1) {
      break;
    }

    switch (curOption) {
      case 'd': //disk name
        state.diskName = optarg;
        hasDisk = true;
        break;
      case 'o': //offset
        state.diskOffset = atol(optarg);
        hasOffset = true;
        break;
      case 's': //size
        state.fileSize = atol(optarg);
        hasSize = true;
        break;
      case 'k': { //decryption keys (12345,12345,12345)
        //Split argument by comma into three integers
        char* token = strtok(optarg, ",");
        uint32_t keys[3] = { 0UL, 0UL, 0UL };
        int index = 0;
        while (token != NULL) {
          if (index > 2) {
            fprintf(stderr, "Too many decryption keys specified with --keys; only 3 are allowed.\n");
            errorAndExit();
          }
          keys[index] = atoi(token);
          index += 1;
          token = strtok(NULL, ",");
        }
        if (index < 3) {
          fprintf(stderr, "Not enough decryption keys specified with --keys; 3 are required but only found %i.\n", index);
          errorAndExit();
        }
        //Initialize decryption (pass decryption keys)
        initDecryptor(keys[0], keys[1], keys[2]);
        state.isEncrypted = true;
        break;
      }
      case 'p': //previous file for xdelta3
        state.prevFile = optarg;
        break;
      case 't': //target file path where extracted file is saved to
        state.target = optarg;
        break;
      case 'l': //disk write limit
        setDiskSpeed(atol(optarg));
        break;
      case '?':
        errorAndExit();
        break;
      default:
        fprintf(stderr, "Unknown option '%c'.\n", (char)curOption);
        errorAndExit();
    }
  }

  if (!hasDisk) {
    fprintf(stderr, "Missing required argument --disk.\n");
    errorAndExit();
  }

  if (!hasOffset) {
    fprintf(stderr, "Missing required argument --offset.\n");
    errorAndExit();
  }

  if (!hasSize) {
    fprintf(stderr, "Missing required argument --size.\n");
    errorAndExit();
  }

  if (optind < argc) {
    fprintf(stderr, "Found %i argument(s) without an option. All arguments must be preceded by an option.\n", argc - optind);
    errorAndExit();
  }

  return state;
}