TarWriter: Set "00" to Ustar version field.

Most (maybe all?) tar commands can handle tar archives with blank
version fields, but POSIX requires "00" to be set to the field, so
doing it is good for compliance.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291479 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Support/TarWriter.cpp b/lib/Support/TarWriter.cpp
index f79b364..58abffc 100644 (file)
--- a/lib/Support/TarWriter.cpp
+++ b/lib/Support/TarWriter.cpp
@@ -54,6 +54,13 @@ struct UstarHeader {
 };
 static_assert(sizeof(UstarHeader) == BlockSize, "invalid Ustar header");
 
+static UstarHeader makeUstarHeader() {
+  UstarHeader Hdr = {};
+  memcpy(Hdr.Magic, "ustar", 5); // Ustar magic
+  memcpy(Hdr.Version, "00", 2);  // Ustar version
+  return Hdr;
+}
+
 // A PAX attribute is in the form of "<length> <key>=<value>\n"
 // where <length> is the length of the entire string including
 // the length field itself. An example string is this.
@@ -98,10 +105,9 @@ static void writePaxHeader(raw_fd_ostream &OS, StringRef Path) {
   std::string PaxAttr = formatPax("path", Path);
 
   // Create a 512-byte header.
-  UstarHeader Hdr = {};
+  UstarHeader Hdr = makeUstarHeader();
   snprintf(Hdr.Size, sizeof(Hdr.Size), "%011zo", PaxAttr.size());
-  Hdr.TypeFlag = 'x';            // PAX magic
-  memcpy(Hdr.Magic, "ustar", 6); // Ustar magic
+  Hdr.TypeFlag = 'x'; // PAX magic
   computeChecksum(Hdr);
 
   // Write them down.
@@ -138,11 +144,10 @@ static void writeUstarHeader(raw_fd_ostream &OS, StringRef Path, size_t Size) {
   StringRef Name;
   std::tie(Prefix, Name) = splitPath(Path);
 
-  UstarHeader Hdr = {};
+  UstarHeader Hdr = makeUstarHeader();
   memcpy(Hdr.Name, Name.data(), Name.size());
   memcpy(Hdr.Mode, "0000664", 8);
   snprintf(Hdr.Size, sizeof(Hdr.Size), "%011zo", Size);
-  memcpy(Hdr.Magic, "ustar", 6);
   memcpy(Hdr.Prefix, Prefix.data(), Prefix.size());
   computeChecksum(Hdr);
   OS << StringRef(reinterpret_cast<char *>(&Hdr), sizeof(Hdr));