Add APT::Acquire::$(host)::By-Hash=1 knob, add Acquire-By-Hash to Release file

The by-hash can be configured on a per-hostname basis and a Release
file can indicate that it has by-hash support via a new flag.

The location of the hash now matches the AptByHash spec

apt-pkg/acquire-item.cc

@@ -1018,31 +1018,31 @@ void pkgAcqIndex::Init(string const &URI, string const &URIDesc, string const &S
       indexRecords::checkSum *Record = MetaIndexParser->Lookup(MetaKey);
       if(Record)
          FileSize = Record->Size;
-   }
 
-   // do the request by-hash
-   // TODO:
-   //  - add Support-By-Hash hashtype into Release time so that we
-   //    know we can use it
-   //  - (maybe?) add support for by-hash into the sources.list as flag
-   //  - make apt-ftparchive generate the hashes (and expire?)
-   if(_config->FindB("APT::Acquire::By-Hash", false) == true &&
-      MetaIndexParser)
-   {
-      indexRecords::checkSum *Record = MetaIndexParser->Lookup(MetaKey);
-      if(Record)
+      // TODO:
+      //  - (maybe?) add support for by-hash into the sources.list as flag
+      //  - make apt-ftparchive generate the hashes (and expire?)
+      // do the request by-hash
+      std::string HostKnob = "APT::Acquire::" + ::URI(URI).Host + "::By-Hash";
+      if(_config->FindB("APT::Acquire::By-Hash", false) == true ||
+         _config->FindB(HostKnob, false) == true ||
+         MetaIndexParser->GetSupportsAcquireByHash())
       {
-         // FIXME: make the hash used a config option or read from release file
-         const HashString *TargetHash = Record->Hashes.find("SHA256");
-         std::string ByHash = "/by-hash/" + TargetHash->HashValue();
-         size_t trailing_slash = Desc.URI.find_last_of("/");
-         Desc.URI = Desc.URI.replace(trailing_slash,
-                                     Desc.URI.substr(trailing_slash+1).size()+1,
-                                     ByHash);
-         std::cerr << Desc.URI << std::endl;
-      } else {
-         _error->Warning("By-Hash requested but can not find record for %s",
-                         MetaKey.c_str());
+         indexRecords::checkSum *Record = MetaIndexParser->Lookup(MetaKey);
+         if(Record)
+         {
+            // FIXME: should we really use the best hash here? or a fixed one?
+            const HashString *TargetHash = Record->Hashes.find("");
+            std::string ByHash = "/by-hash/" + TargetHash->HashType() + "/" + TargetHash->HashValue();
+            size_t trailing_slash = Desc.URI.find_last_of("/");
+            Desc.URI = Desc.URI.replace(
+               trailing_slash,
+               Desc.URI.substr(trailing_slash+1).size()+1,
+               ByHash);
+         } else {
+            _error->Warning("By-Hash requested but can not find record for %s",
+                            MetaKey.c_str());
+         }
       }
    }
 

apt-pkg/indexrecords.cc

@@ -37,6 +37,11 @@ APT_PURE string indexRecords::GetSuite() const
    return this->Suite;
 }
 
+APT_PURE bool indexRecords::GetSupportsAcquireByHash() const
+{
+   return this->SupportsAcquireByHash;
+}
+
 APT_PURE bool indexRecords::CheckDist(const string MaybeDist) const
 {
    return (this->Dist == MaybeDist
@@ -86,6 +91,8 @@ bool indexRecords::Load(const string Filename)				/*{{{*/
       strprintf(ErrorText, _("No sections in Release file %s"), Filename.c_str());
       return false;
    }
+   // FIXME: find better tag name
+   SupportsAcquireByHash = Section.FindB("Acquire-By-Hash", false);
 
    Suite = Section.FindS("Suite");
    Dist = Section.FindS("Codename");
@@ -243,6 +250,6 @@ indexRecords::indexRecords()
 }
 
 indexRecords::indexRecords(const string ExpectedDist) :
-   ExpectedDist(ExpectedDist), ValidUntil(0)
+   ExpectedDist(ExpectedDist), ValidUntil(0), SupportsAcquireByHash(false)
 {
 }

apt-pkg/indexrecords.h

@@ -26,12 +26,15 @@ class indexRecords
    public:
    struct checkSum;
    std::string ErrorText;
+   // dpointer (for later9
+   void * d;
    
    protected:
    std::string Dist;
    std::string Suite;
    std::string ExpectedDist;
    time_t ValidUntil;
+   bool SupportsAcquireByHash;
 
    std::map<std::string,checkSum *> Entries;
 
@@ -49,6 +52,7 @@ class indexRecords
    virtual bool Load(std::string Filename);
    std::string GetDist() const;
    std::string GetSuite() const;
+   bool GetSupportsAcquireByHash() const;
    time_t GetValidUntil() const;
    virtual bool CheckDist(const std::string MaybeDist) const;
    std::string GetExpectedDist() const;

apt-pkg/tagfile.cc

@@ -518,6 +518,17 @@ unsigned long long pkgTagSection::FindULL(const char *Tag, unsigned long long co
    return Result;
 }
 									/*}}}*/
+// TagSection::FindB - Find boolean value                		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgTagSection::FindB(const char *Tag, bool const &Default) const
+{
+   const char *Start, *Stop;
+   if (Find(Tag, Start, Stop) == false)
+      return Default;
+   return StringToBool(string(Start, Stop));
+}
+									/*}}}*/
 // TagSection::FindFlag - Locate a yes/no type flag			/*{{{*/
 // ---------------------------------------------------------------------
 /* The bits marked in Flag are masked on/off in Flags */

apt-pkg/tagfile.h

@@ -62,7 +62,8 @@ class pkgTagSection
    bool Find(const char *Tag,const char *&Start, const char *&End) const;
    bool Find(const char *Tag,unsigned int &Pos) const;
    std::string FindS(const char *Tag) const;
-   signed int FindI(const char *Tag,signed long Default = 0) const ;
+   signed int FindI(const char *Tag,signed long Default = 0) const;
+   bool FindB(const char *Tag, bool const &Default = false) const;
    unsigned long long FindULL(const char *Tag, unsigned long long const &Default = 0) const;
    bool FindFlag(const char *Tag,unsigned long &Flags,
 		 unsigned long Flag) const;

test/integration/test-apt-by-hash-update

@@ -14,17 +14,19 @@ setupaptarchive --no-update
 APTARCHIVE=$(readlink -f ./aptarchive)
 
 # make Packages *only* accessable by-hash for this test
-mkdir -p aptarchive/dists/unstable/main/binary-i386/by-hash
-(cd  aptarchive/dists/unstable/main/binary-i386/by-hash && 
-     mv ../Packages* . &&
-     ln -s Packages.gz  $(sha256sum Packages.gz|cut -f1 -d' ') )
+mkdir -p aptarchive/dists/unstable/main/binary-i386/by-hash/SHA512
+(cd  aptarchive/dists/unstable/main/binary-i386/by-hash/SHA512 && 
+     mv ../../Packages* . &&
+     ln -s Packages.gz  $(sha512sum Packages.gz|cut -f1 -d' ') )
 
 # add sources
-mkdir -p aptarchive/dists/unstable/main/source/by-hash
-(cd  aptarchive/dists/unstable/main/source/by-hash && 
-     ln -s ../Sources.gz  $(sha256sum ../Sources.gz|cut -f1 -d' ') 
+mkdir -p aptarchive/dists/unstable/main/source/by-hash/SHA512
+(cd  aptarchive/dists/unstable/main/source/by-hash/SHA512 && 
+     ln -s ../../Sources.gz  $(sha512sum ../../Sources.gz|cut -f1 -d' ') 
 )
 
+# we moved the Packages file away, normal update won't work
+testfailure aptget upate
 
 # ensure we do not know about "foo"
 testequal "Reading package lists...
@@ -34,6 +36,14 @@ E: Unable to locate package foo" aptget install -q -s foo
 # ensure we can apt-get update by hash
 testsuccess aptget update -o APT::Acquire::By-Hash=1
 
-# ensure it keeps working
+# ensure it works
 testequal "Inst foo (1.0 unstable [all])
-Conf foo (1.0 unstable [all])" aptget install -qq -s foo
+Conf foo (1.0 unstable [all])" aptget install -qq -s foo
+
+# add magic string to Release file ...
+MAGIC="Acquire-By-Hash: true"
+sed -i "s#Suite: unstable#Suite: unstable\n$MAGIC#" aptarchive/dists/unstable/Release
+signreleasefiles
+# ... and verify that it fetches by hash now
+testsuccess aptget update
+