[llvm] r291479 - TarWriter: Set "00" to Ustar version field.

[Rui Ueyama via llvm-commits]

Author: ruiu
Date: Mon Jan  9 15:20:42 2017
New Revision: 291479

URL: http://llvm.org/viewvc/llvm-project?rev=291479&view=rev
Log:
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.

Modified:
    llvm/trunk/lib/Support/TarWriter.cpp

Modified: llvm/trunk/lib/Support/TarWriter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/TarWriter.cpp?rev=291479&r1=291478&r2=291479&view=diff
==============================================================================
--- llvm/trunk/lib/Support/TarWriter.cpp (original)
+++ llvm/trunk/lib/Support/TarWriter.cpp Mon Jan  9 15:20:42 2017
@@ -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_ostrea
   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_ostr
   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));