Fix spurious warnings of problems on MBR disks

3 files changed, 21 insertions, 6 deletions

diff --git a/NEWS b/NEWS
index f74bad0..a7131aa 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,10 @@
+1.0.7 (?/??/2021):
+------------------
+
+- Fixed bug that caused spurious warnings about the partition table
+  header claiming an invalid size of partition entries when reading
+  some MBR disks.
+
 1.0.6 (1/13/2021):
 ------------------
 
diff --git a/gpt.cc b/gpt.cc
index 1b4e10f..842dfb1 100644
--- a/gpt.cc
+++ b/gpt.cc
@@ -1042,11 +1042,19 @@ int GPTData::LoadHeader(struct GPTHeader *header, DiskIO & disk, uint64_t sector
    *crcOk = CheckHeaderCRC(&tempHeader);
 
    if (tempHeader.sizeOfPartitionEntries != sizeof(GPTPart)) {
-       cerr << "Warning: Partition table header claims that the size of partition table\n";
-       cerr << "entries is " << tempHeader.sizeOfPartitionEntries << " bytes, but this program ";
-       cerr << " supports only " << sizeof(GPTPart) << "-byte entries.\n";
-       cerr << "Adjusting accordingly, but partition table may be garbage.\n";
-       tempHeader.sizeOfPartitionEntries = sizeof(GPTPart);
+      // Print the below warning only if the CRC is OK -- but correct the
+      // problem either way. The warning is printed only on a valid CRC
+      // because otherwise this warning will display inappropriately when
+      // reading MBR disks. If the CRC is invalid, then a warning about
+      // that will be shown later, so the user will still know that
+      // something is wrong.
+      if (*crcOk) {
+         cerr << "Warning: Partition table header claims that the size of partition table\n";
+         cerr << "entries is " << tempHeader.sizeOfPartitionEntries << " bytes, but this program ";
+         cerr << " supports only " << sizeof(GPTPart) << "-byte entries.\n";
+         cerr << "Adjusting accordingly, but partition table may be garbage.\n";
+      }
+      tempHeader.sizeOfPartitionEntries = sizeof(GPTPart);
    }
 
    if (allOK && (numParts != tempHeader.numParts) && *crcOk) {
diff --git a/support.h b/support.h
index d87fe9a..e3e1e12 100644
--- a/support.h
+++ b/support.h
@@ -8,7 +8,7 @@
 #include <stdlib.h>
 #include <string>
 
-#define GPTFDISK_VERSION "1.0.6"
+#define GPTFDISK_VERSION "1.0.6.1"
 
 #if defined (__FreeBSD__) || defined (__FreeBSD_kernel__) || defined (__APPLE__)
 // Darwin (Mac OS) & FreeBSD: disk IOCTLs are different, and there is no lseek64