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1 /*
2     Implementation of GPTData class derivative with popt-based command
3     line processing
4     Copyright (C) 2010-2024 Roderick W. Smith
5 
6     This program is free software; you can redistribute it and/or modify
7     it under the terms of the GNU General Public License as published by
8     the Free Software Foundation; either version 2 of the License, or
9     (at your option) any later version.
10 
11     This program is distributed in the hope that it will be useful,
12     but WITHOUT ANY WARRANTY; without even the implied warranty of
13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14     GNU General Public License for more details.
15 
16     You should have received a copy of the GNU General Public License along
17     with this program; if not, write to the Free Software Foundation, Inc.,
18     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
19 */
20 
21 #include <string.h>
22 #include <string>
23 #include <iostream>
24 #include <sstream>
25 #include <errno.h>
26 #include <popt.h>
27 #include "gptcl.h"
28 
29 using namespace std;
30 
GPTDataCL(void)31 GPTDataCL::GPTDataCL(void) {
32    attributeOperation = backupFile = partName = hybrids = newPartInfo = NULL;
33    mbrParts = twoParts = outDevice = typeCode = partGUID = diskGUID = NULL;
34    alignment = DEFAULT_ALIGNMENT;
35    alignEnd = false;
36    deletePartNum = infoPartNum = largestPartNum = bsdPartNum = 0;
37    tableSize = GPT_SIZE;
38 } // GPTDataCL constructor
39 
GPTDataCL(string filename)40 GPTDataCL::GPTDataCL(string filename) {
41 } // GPTDataCL constructor with filename
42 
~GPTDataCL(void)43 GPTDataCL::~GPTDataCL(void) {
44 } // GPTDataCL destructor
45 
LoadBackupFile(string backupFile,int & saveData,int & neverSaveData)46 void GPTDataCL::LoadBackupFile(string backupFile, int &saveData, int &neverSaveData) {
47    if (LoadGPTBackup(backupFile) == 1) {
48       JustLooking(0);
49       saveData = 1;
50    } else {
51       saveData = 0;
52       neverSaveData = 1;
53       cerr << "Error loading backup file!\n";
54    } // else
55 } // GPTDataCL::LoadBackupFile()
56 
57 // Perform the actions specified on the command line. This is necessarily one
58 // monster of a function!
59 // Returns values:
60 // 0 = success
61 // 1 = too few arguments
62 // 2 = error when reading partition table
63 // 3 = non-GPT disk and no -g option
64 // 4 = unable to save changes
65 // 8 = disk replication operation (-R) failed
DoOptions(int argc,char * argv[])66 int GPTDataCL::DoOptions(int argc, char* argv[]) {
67    GPTData secondDevice;
68    int opt, numOptions = 0, saveData = 0, neverSaveData = 0;
69    int partNum = 0, newPartNum = -1, saveNonGPT = 1, retval = 0, pretend = 0;
70    int byteSwapPartNum = 0;
71    uint64_t low, high, startSector, endSector, sSize, mainTableLBA, secondTableLBA;
72    uint64_t temp; // temporary variable; free to use in any case
73    char *device;
74    string cmd, typeGUID, name;
75    PartType typeHelper;
76 
77    struct poptOption theOptions[] =
78    {
79       {"attributes", 'A', POPT_ARG_STRING, &attributeOperation, 'A', "operate on partition attributes",
80           "list|[partnum:show|or|nand|xor|=|set|clear|toggle|get[:bitnum|hexbitmask]]"},
81       {"set-alignment", 'a', POPT_ARG_INT, &alignment, 'a', "set sector alignment", "value"},
82       {"backup", 'b', POPT_ARG_STRING, &backupFile, 'b', "backup GPT to file", "file"},
83       {"byte-swap-name", 'B',  POPT_ARG_INT, &byteSwapPartNum, 'B', "byte-swap partition's name", "partnum"},
84       {"change-name", 'c', POPT_ARG_STRING, &partName, 'c', "change partition's name", "partnum:name"},
85       {"recompute-chs", 'C', POPT_ARG_NONE, NULL, 'C', "recompute CHS values in protective/hybrid MBR", ""},
86       {"delete", 'd', POPT_ARG_INT, &deletePartNum, 'd', "delete a partition", "partnum"},
87       {"display-alignment", 'D', POPT_ARG_NONE, NULL, 'D', "show number of sectors per allocation block", ""},
88       {"move-second-header", 'e', POPT_ARG_NONE, NULL, 'e', "move second/backup header to end of disk", ""},
89       {"end-of-largest", 'E', POPT_ARG_NONE, NULL, 'E', "show end of largest free block", ""},
90       {"first-in-largest", 'f', POPT_ARG_NONE, NULL, 'f', "show start of the largest free block", ""},
91       {"first-aligned-in-largest", 'F', POPT_ARG_NONE, NULL, 'F', "show start of the largest free block, aligned", ""},
92       {"mbrtogpt", 'g', POPT_ARG_NONE, NULL, 'g', "convert MBR to GPT", ""},
93       {"randomize-guids", 'G', POPT_ARG_NONE, NULL, 'G', "randomize disk and partition GUIDs", ""},
94       {"hybrid", 'h', POPT_ARG_STRING, &hybrids, 'h', "create hybrid MBR", "partnum[:partnum...][:EE]"},
95       {"info", 'i', POPT_ARG_INT, &infoPartNum, 'i', "show detailed information on partition", "partnum"},
96       {"align-end", 'I', POPT_ARG_NONE, NULL, 'I', "align partition end points", ""},
97       {"move-main-table", 'j', POPT_ARG_INT, &mainTableLBA, 'j', "change the start sector of the main partition table", "sector"},
98       {"move-backup-table", 'k', POPT_ARG_INT, &secondTableLBA, 'k', "change the start sector of the second/backup partition table", "sector"},
99       {"load-backup", 'l', POPT_ARG_STRING, &backupFile, 'l', "load GPT backup from file", "file"},
100       {"list-types", 'L', POPT_ARG_NONE, NULL, 'L', "list known partition types", ""},
101       {"gpttombr", 'm', POPT_ARG_STRING, &mbrParts, 'm', "convert GPT to MBR", "partnum[:partnum...]"},
102       {"new", 'n', POPT_ARG_STRING, &newPartInfo, 'n', "create new partition", "partnum:start:end"},
103       {"largest-new", 'N', POPT_ARG_INT, &largestPartNum, 'N', "create largest possible new partition", "partnum"},
104       {"clear", 'o', POPT_ARG_NONE, NULL, 'o', "clear partition table", ""},
105       {"print-mbr", 'O', POPT_ARG_NONE, NULL, 'O', "print MBR partition table", ""},
106       {"print", 'p', POPT_ARG_NONE, NULL, 'p', "print partition table", ""},
107       {"pretend", 'P', POPT_ARG_NONE, NULL, 'P', "make changes in memory, but don't write them", ""},
108       {"transpose", 'r', POPT_ARG_STRING, &twoParts, 'r', "transpose two partitions", "partnum:partnum"},
109       {"replicate", 'R', POPT_ARG_STRING, &outDevice, 'R', "replicate partition table", "device_filename"},
110       {"sort", 's', POPT_ARG_NONE, NULL, 's', "sort partition table entries", ""},
111       {"resize-table", 'S', POPT_ARG_INT, &tableSize, 'S', "resize partition table", "numparts"},
112       {"typecode", 't', POPT_ARG_STRING, &typeCode, 't', "change partition type code", "partnum:{hexcode|GUID}"},
113       {"transform-bsd", 'T', POPT_ARG_INT, &bsdPartNum, 'T', "transform BSD disklabel partition to GPT", "partnum"},
114       {"partition-guid", 'u', POPT_ARG_STRING, &partGUID, 'u', "set partition GUID", "partnum:guid"},
115       {"disk-guid", 'U', POPT_ARG_STRING, &diskGUID, 'U', "set disk GUID", "guid"},
116       {"verify", 'v', POPT_ARG_NONE, NULL, 'v', "check partition table integrity", ""},
117       {"version", 'V', POPT_ARG_NONE, NULL, 'V', "display version information", ""},
118       {"zap", 'z', POPT_ARG_NONE, NULL, 'z', "zap (destroy) GPT (but not MBR) data structures", ""},
119       {"zap-all", 'Z', POPT_ARG_NONE, NULL, 'Z', "zap (destroy) GPT and MBR data structures", ""},
120       POPT_AUTOHELP { NULL, 0, 0, NULL, 0 }
121    };
122 
123    // Create popt context...
124    poptCon = poptGetContext(NULL, argc, (const char**) argv, theOptions, 0);
125 
126    poptSetOtherOptionHelp(poptCon, " [OPTION...] <device>");
127 
128    if (argc < 2) {
129       poptPrintUsage(poptCon, stderr, 0);
130       return 1;
131    }
132 
133    // Do one loop through the options to find the device filename and deal
134    // with options that don't require a device filename, to flag destructive
135    // (o, z, or Z) options, and to flag presence of a --pretend/-P option
136    while ((opt = poptGetNextOpt(poptCon)) > 0) {
137       switch (opt) {
138          case 'A':
139             cmd = GetString(attributeOperation, 1);
140             if (cmd == "list")
141                Attributes::ListAttributes();
142             break;
143          case 'L':
144             typeHelper.ShowAllTypes(0);
145             break;
146          case 'P':
147             pretend = 1;
148             break;
149          case 'V':
150             cout << "GPT fdisk (sgdisk) version " << GPTFDISK_VERSION << "\n\n";
151             break;
152          default:
153             break;
154       } // switch
155       numOptions++;
156    } // while
157 
158    // Assume first non-option argument is the device filename....
159    device = (char*) poptGetArg(poptCon);
160 
161    if (device != NULL) {
162       device = strdup(device);
163       poptResetContext(poptCon);
164       JustLooking(); // reset as necessary
165       BeQuiet(); // Tell called functions to be less verbose & interactive
166       if (LoadPartitions((string) device)) {
167          if ((WhichWasUsed() == use_mbr) || (WhichWasUsed() == use_bsd))
168             saveNonGPT = 0; // flag so we don't overwrite unless directed to do so
169          sSize = GetBlockSize();
170          while ((opt = poptGetNextOpt(poptCon)) > 0) {
171             switch (opt) {
172                case 'A': {
173                   if (cmd != "list") {
174                      partNum = (int) GetInt(attributeOperation, 1) - 1;
175                      if (partNum < 0)
176                         partNum = newPartNum;
177                      if ((partNum >= 0) && (partNum < (int) GetNumParts())) {
178                         switch (ManageAttributes(partNum, GetString(attributeOperation, 2),
179                            GetString(attributeOperation, 3))) {
180                            case -1:
181                               saveData = 0;
182                               neverSaveData = 1;
183                               break;
184                            case 1:
185                               JustLooking(0);
186                               saveData = 1;
187                               break;
188                            default:
189                               break;
190                         } // switch
191                      } else {
192                         cerr << "Error: Invalid partition number " << partNum + 1 << "\n";
193                         saveData = 0;
194                         neverSaveData = 1;
195                      } // if/else reasonable partition #
196                   } // if (cmd != "list")
197                   break;
198                } // case 'A':
199                case 'a':
200                   SetAlignment(alignment);
201                   break;
202                case 'B':
203                   if (IsUsedPartNum(byteSwapPartNum - 1)) {
204                      partitions[byteSwapPartNum - 1].ReverseNameBytes();
205                      cout << "Changed partition " << byteSwapPartNum << "'s name to "
206                           << partitions[byteSwapPartNum - 1].GetDescription() << "\n";
207                      JustLooking(0);
208                      saveData = 1;
209                   }
210                   break;
211                case 'b':
212                   SaveGPTBackup(backupFile);
213                   free(backupFile);
214                   break;
215                case 'c':
216                   JustLooking(0);
217                   partNum = (int) GetInt(partName, 1) - 1;
218                   if (partNum < 0)
219                      partNum = newPartNum;
220                   if ((partNum >= 0) && (partNum < (int) GetNumParts())) {
221                      name = GetString(partName, 2);
222                      if (SetName(partNum, (UnicodeString) name.c_str())) {
223                         saveData = 1;
224                      } else {
225                         cerr << "Unable to set partition " << partNum + 1
226                              << "'s name to '" << GetString(partName, 2) << "'!\n";
227                         neverSaveData = 1;
228                      } // if/else
229                      free(partName);
230                   }
231                   break;
232                case 'C':
233                   JustLooking(0);
234                   RecomputeCHS();
235                   saveData = 1;
236                   break;
237                case 'd':
238                   JustLooking(0);
239                   if (DeletePartition(deletePartNum - 1) == 0) {
240                      cerr << "Error " << errno << " deleting partition!\n";
241                      neverSaveData = 1;
242                   } else saveData = 1;
243                                                       break;
244                case 'D':
245                   cout << GetAlignment() << "\n";
246                   break;
247                case 'e':
248                   JustLooking(0);
249                   MoveSecondHeaderToEnd();
250                   saveData = 1;
251                   break;
252                case 'E':
253                   cout << FindLastInFree(FindFirstInLargest()) << "\n";
254                   break;
255                case 'f':
256                   cout << FindFirstInLargest() << "\n";
257                   break;
258                case 'F':
259                   temp = FindFirstInLargest();
260                   Align(&temp);
261                   cout << temp << "\n";
262                   break;
263                case 'g':
264                   JustLooking(0);
265                   saveData = 1;
266                   saveNonGPT = 1;
267                   break;
268                case 'G':
269                   JustLooking(0);
270                   saveData = 1;
271                   RandomizeGUIDs();
272                   break;
273                case 'h':
274                   JustLooking(0);
275                   if (BuildMBR(hybrids, 1) == 1)
276                      saveData = 1;
277                   break;
278                case 'i':
279                   ShowPartDetails(infoPartNum - 1);
280                   break;
281                case 'I':
282                   alignEnd = true;
283                   break;
284                case 'j':
285                    if (MoveMainTable(mainTableLBA)) {
286                        JustLooking(0);
287                        saveData = 1;
288                    } else {
289                        neverSaveData = 1;
290                    } // if/else
291                    break;
292                case 'k':
293                    if (MoveSecondTable(secondTableLBA)) {
294                        JustLooking(0);
295                        saveData = 1;
296                    } else {
297                        neverSaveData = 1;
298                    } // if/else
299                     break;
300                case 'l':
301                   LoadBackupFile(backupFile, saveData, neverSaveData);
302                   free(backupFile);
303                   break;
304                case 'L':
305                   break;
306                case 'm':
307                   JustLooking(0);
308                   if (BuildMBR(mbrParts, 0) == 1) {
309                      if (!pretend) {
310                         if (SaveMBR()) {
311                            DestroyGPT();
312                         } else
313                            cerr << "Problem saving MBR!\n";
314                      } // if
315                      saveNonGPT = 0;
316                      pretend = 1; // Not really, but works around problem if -g is used with this...
317                      saveData = 0;
318                   } // if
319                   break;
320                case 'n':
321                   JustLooking(0);
322                   newPartNum = (int) GetInt(newPartInfo, 1) - 1;
323                   if (newPartNum < 0)
324                      newPartNum = FindFirstFreePart();
325                   low = FindFirstInLargest();
326                   Align(&low);
327                   high = FindLastInFree(low, alignEnd);
328                   startSector = IeeeToInt(GetString(newPartInfo, 2), sSize, low, high, sectorAlignment, low);
329                   endSector = IeeeToInt(GetString(newPartInfo, 3), sSize, startSector, high, sectorAlignment, high);
330                   if (CreatePartition(newPartNum, startSector, endSector)) {
331                      saveData = 1;
332                   } else {
333                      cerr << "Could not create partition " << newPartNum + 1 << " from "
334                           << startSector << " to " << endSector << "\n";
335                      neverSaveData = 1;
336                   } // if/else
337                   free(newPartInfo);
338                   break;
339                case 'N':
340                   JustLooking(0);
341                   startSector = FindFirstInLargest();
342                   Align(&startSector);
343                   endSector = FindLastInFree(startSector, alignEnd);
344                   if (largestPartNum <= 0) {
345                      largestPartNum = FindFirstFreePart() + 1;
346                      newPartNum = largestPartNum - 1;
347                   }
348                   if (CreatePartition(largestPartNum - 1, startSector, endSector)) {
349                      saveData = 1;
350                   } else {
351                      cerr << "Could not create partition " << largestPartNum << " from "
352                      << startSector << " to " << endSector << "\n";
353                      neverSaveData = 1;
354                   } // if/else
355                   break;
356                case 'o':
357                   JustLooking(0);
358                   ClearGPTData();
359                   saveData = 1;
360                   break;
361                case 'O':
362                    DisplayMBRData();
363                    break;
364                case 'p':
365                   DisplayGPTData();
366                   break;
367                case 'P':
368                   pretend = 1;
369                   break;
370                case 'r':
371                   JustLooking(0);
372                   uint64_t p1, p2;
373                   p1 = GetInt(twoParts, 1) - 1;
374                   p2 = GetInt(twoParts, 2) - 1;
375                   if (SwapPartitions((uint32_t) p1, (uint32_t) p2) == 0) {
376                      neverSaveData = 1;
377                      cerr << "Cannot swap partitions " << p1 + 1 << " and " << p2 + 1 << "\n";
378                   } else saveData = 1;
379                                                       break;
380                case 'R':
381                   secondDevice = *this;
382                   secondDevice.SetDisk(outDevice);
383                   secondDevice.JustLooking(0);
384                   if (!secondDevice.SaveGPTData(1))
385                      retval = 8;
386                   break;
387                case 's':
388                   JustLooking(0);
389                   SortGPT();
390                   saveData = 1;
391                   break;
392                case 'S':
393                   JustLooking(0);
394                   if (SetGPTSize(tableSize) == 0)
395                      neverSaveData = 1;
396                   else
397                      saveData = 1;
398                   break;
399                case 't':
400                   JustLooking(0);
401                   partNum = (int) GetInt(typeCode, 1) - 1;
402                   if (partNum < 0)
403                      partNum = newPartNum;
404                   if ((partNum >= 0) && (partNum < (int) GetNumParts())) {
405                      typeHelper = GetString(typeCode, 2);
406                      if ((typeHelper != PartType::unusedPartType) &&
407                          (ChangePartType(partNum, typeHelper))) {
408                         saveData = 1;
409                         } else {
410                            cerr << "Could not change partition " << partNum + 1
411                            << "'s type code to " << GetString(typeCode, 2) << "!\n";
412                            neverSaveData = 1;
413                         } // if/else
414                      free(typeCode);
415                   }
416                   break;
417                case 'T':
418                   JustLooking(0);
419                   XFormDisklabel(bsdPartNum - 1);
420                   saveData = 1;
421                   break;
422                case 'u':
423                   JustLooking(0);
424                   saveData = 1;
425                   partNum = (int) GetInt(partGUID, 1) - 1;
426                   if (partNum < 0)
427                      partNum = newPartNum;
428                   if ((partNum >= 0) && (partNum < (int) GetNumParts())) {
429                      SetPartitionGUID(partNum, GetString(partGUID, 2).c_str());
430                   }
431                   break;
432                case 'U':
433                   JustLooking(0);
434                   saveData = 1;
435                   SetDiskGUID(diskGUID);
436                   break;
437                case 'v':
438                   Verify();
439                   break;
440                case 'z':
441                   if (!pretend) {
442                      DestroyGPT();
443                   } // if
444                   saveNonGPT = 1;
445                   saveData = 0;
446                   break;
447                case 'Z':
448                   if (!pretend) {
449                      DestroyGPT();
450                      DestroyMBR();
451                   } // if
452                   saveNonGPT = 1;
453                   saveData = 0;
454                   break;
455                default:
456                   cerr << "Unknown option (-" << opt << ")!\n";
457                   break;
458                } // switch
459          } // while
460       } else { // if loaded OK
461          poptResetContext(poptCon);
462          // Do a few types of operations even if there are problems....
463          while ((opt = poptGetNextOpt(poptCon)) > 0) {
464             switch (opt) {
465                case 'l':
466                   LoadBackupFile(backupFile, saveData, neverSaveData);
467                   cout << "Information: Loading backup partition table; will override earlier problems!\n";
468                   free(backupFile);
469                   retval = 0;
470                   break;
471                case 'o':
472                   JustLooking(0);
473                   ClearGPTData();
474                   saveData = 1;
475                   cout << "Information: Creating fresh partition table; will override earlier problems!\n";
476                   retval = 0;
477                   break;
478                case 'v':
479                   cout << "Verification may miss some problems or report too many!\n";
480                   Verify();
481                   break;
482                case 'z':
483                   if (!pretend) {
484                      DestroyGPT();
485                   } // if
486                   saveNonGPT = 1;
487                   saveData = 0;
488                   break;
489                case 'Z':
490                   if (!pretend) {
491                      DestroyGPT();
492                      DestroyMBR();
493                   } // if
494                   saveNonGPT = 1;
495                   saveData = 0;
496                   break;
497             } // switch
498          } // while
499          retval = 2;
500       } // if/else loaded OK
501       if ((saveData) && (!neverSaveData) && (saveNonGPT) && (!pretend)) {
502          if (!SaveGPTData(1))
503             retval = 4;
504       }
505       if (saveData && (!saveNonGPT)) {
506          cout << "Non-GPT disk; not saving changes. Use -g to override.\n";
507          retval = 3;
508       } // if
509       if (neverSaveData) {
510          cerr << "Error encountered; not saving changes.\n";
511          retval = 4;
512       } // if
513       free(device);
514    } // if (device != NULL)
515    poptFreeContext(poptCon);
516    return retval;
517 } // GPTDataCL::DoOptions()
518 
519 // Create a hybrid or regular MBR from GPT data structures
BuildMBR(char * argument,int isHybrid)520 int GPTDataCL::BuildMBR(char* argument, int isHybrid) {
521    int numParts, allOK = 1, i, origPartNum;
522    int eeLast = 0, mbrNum = 0;
523    MBRPart newPart;
524    BasicMBRData newMBR;
525 
526    if (argument != NULL) {
527       numParts = CountColons(argument) + 1;
528       if (isHybrid) {
529          eeLast = GetString(argument, numParts) == "EE";
530          if (eeLast) {
531             numParts--;
532          }
533       }
534 
535       if (numParts <= (4 - isHybrid)) {
536          newMBR.SetDisk(GetDisk());
537          for (i = 0; i < numParts; i++) {
538             origPartNum = GetInt(argument, i + 1) - 1;
539             if (IsUsedPartNum(origPartNum) && (partitions[origPartNum].IsSizedForMBR() == MBR_SIZED_GOOD)) {
540                mbrNum = i + (isHybrid && ! eeLast);
541                newPart.SetInclusion(PRIMARY);
542                newPart.SetLocation(operator[](origPartNum).GetFirstLBA(),
543                                    operator[](origPartNum).GetLengthLBA());
544                newPart.SetStatus(0);
545                newPart.SetType((uint8_t)(operator[](origPartNum).GetHexType() / 0x0100));
546                newMBR.AddPart(mbrNum, newPart);
547             } else {
548                cerr << "Original partition " << origPartNum + 1 << " does not exist or is too big! Aborting operation!\n";
549                allOK = 0;
550             } // if/else
551          } // for
552          if (isHybrid) {
553             if (eeLast) {
554                mbrNum = i;
555             } else {
556                mbrNum = 0;
557             }
558             newPart.SetInclusion(PRIMARY);
559             newPart.SetLocation(1, newMBR.FindLastInFree(1));
560             newPart.SetStatus(0);
561             newPart.SetType(0xEE);
562             newMBR.AddPart(mbrNum, newPart);
563          } // if
564          if (allOK)
565             SetProtectiveMBR(newMBR);
566       } else allOK = 0;
567    } else allOK = 0;
568    if (!allOK)
569       cerr << "Problem creating MBR!\n";
570    return allOK;
571 } // GPTDataCL::BuildMBR()
572 
573 // Returns the number of colons in argument string, ignoring the
574 // first character (thus, a leading colon is ignored, as GetString()
575 // does).
CountColons(char * argument)576 int CountColons(char* argument) {
577    int num = 0;
578 
579    while ((argument[0] != '\0') && (argument = strchr(&argument[1], ':')))
580       num++;
581 
582    return num;
583 } // GPTDataCL::CountColons()
584 
585 // Extract integer data from argument string, which should be colon-delimited
GetInt(const string & argument,int itemNum)586 uint64_t GetInt(const string & argument, int itemNum) {
587    uint64_t retval;
588 
589    istringstream inString(GetString(argument, itemNum));
590    inString >> retval;
591    return retval;
592 } // GPTDataCL::GetInt()
593 
594 // Extract string data from argument string, which should be colon-delimited
595 // If string begins with a colon, that colon is skipped in the counting. If an
596 // invalid itemNum is specified, returns an empty string.
GetString(string argument,int itemNum)597 string GetString(string argument, int itemNum) {
598    size_t startPos = 0, endPos = 0;
599    string retVal = "";
600    int foundLast = 0;
601    int numFound = 0;
602 
603    if (argument[0] == ':')
604       argument.erase(0, 1);
605    while ((numFound < itemNum) && (!foundLast)) {
606       endPos = argument.find(':', startPos);
607       numFound++;
608       if (endPos == string::npos) {
609          foundLast = 1;
610          endPos = argument.length();
611       } else if (numFound < itemNum) {
612          startPos = endPos + 1;
613       } // if/elseif
614    } // while
615    if ((numFound == itemNum) && (numFound > 0))
616       retVal = argument.substr(startPos, endPos - startPos);
617 
618    return retVal;
619 } // GetString()
620