Checks on backup GPT data structures added to GPTData::DestroyGPT().

1 files changed, 24 insertions, 18 deletions

diff --git a/gpt.cc b/gpt.cc
index fa7b661..d584397 100644
--- a/gpt.cc
+++ b/gpt.cc
@@ -1327,8 +1327,8 @@ int GPTData::DestroyGPT(void) {
       tableSize = numParts * mainHeader.sizeOfPartitionEntries;
       emptyTable = new uint8_t[tableSize];
       if (emptyTable == NULL) {
-         cerr << "Could not allocate memory in GPTData::DestroyGPT()! Terminating!\n";
-         exit(1);
+         cerr << "Could not allocate memory in GPTData::DestroyGPT()! Aborting operation!\n";
+         return(0);
       } // if
       memset(emptyTable, 0, tableSize);
       if (allOK) {
@@ -1337,25 +1337,31 @@ int GPTData::DestroyGPT(void) {
             cerr << "Warning! GPT main partition table not overwritten! Error is " << errno << "\n";
             allOK = 0;
          } // if write failed
-      } // if 
-      if (!myDisk.Seek(secondHeader.partitionEntriesLBA))
-         allOK = 0;
-      if (allOK) {
-         sum = myDisk.Write(emptyTable, tableSize);
-         if (sum != tableSize) {
-            cerr << "Warning! GPT backup partition table not overwritten! Error is "
-                 << errno << "\n";
-            allOK = 0;
-         } // if wrong size written
       } // if
-      if (!myDisk.Seek(secondHeader.currentLBA))
-         allOK = 0;
-      if (allOK) {
-         if (myDisk.Write(blankSector, 512) != 512) { // blank it out
-            cerr << "Warning! GPT backup header not overwritten! Error is " << errno << "\n";
+
+      if (secondHeader.currentLBA == (diskSize - UINT64_C(1))) {
+         if (!myDisk.Seek(secondHeader.partitionEntriesLBA))
             allOK = 0;
+         if (allOK) {
+            sum = myDisk.Write(emptyTable, tableSize);
+            if (sum != tableSize) {
+               cerr << "Warning! GPT backup partition table not overwritten! Error is "
+                    << errno << "\n";
+               allOK = 0;
+            } // if wrong size written
          } // if
-      } // if
+         if (!myDisk.Seek(secondHeader.currentLBA))
+            allOK = 0;
+         if (allOK) {
+            if (myDisk.Write(blankSector, 512) != 512) { // blank it out
+               cerr << "Warning! GPT backup header not overwritten! Error is " << errno << "\n";
+               allOK = 0;
+            } // if
+         } // if
+      } else {
+         cout << "Note: The GPT second header is not at the end of the disk end; therefore,\n"
+              << "it's not being erased.\n";
+      }
       myDisk.DiskSync();
       myDisk.Close();
       cout << "GPT data structures destroyed! You may now partition the disk using fdisk or\n"