128 KiB DSC files ought to be enough for everyone

Your mileage may vary, but don't worry: There is more than one way to
do it, but our one size fits all is not a bigger hammer, but an entire
roundhouse kick! So brace yourself for the tl;dr: The limit is gone.*

Beware: This fixes also the problem that a double newline is
unconditionally added 'later' which is an overcommitment in case
the dsc filesize is limit-2 <= x <= limit.

* limited to numbers fitting into an unsigned long long.

Closes: 774893

4 files changed, 41 insertions, 44 deletions

diff --git a/ftparchive/cachedb.cc b/ftparchive/cachedb.cc
index 0901492f7..c73a64fb7 100644
--- a/ftparchive/cachedb.cc
+++ b/ftparchive/cachedb.cc
@@ -328,12 +328,12 @@ bool CacheDB::LoadSource()
    if (Dsc.Read(FileName) == false)
       return false;
 
-   if (Dsc.Data == 0)
+   if (Dsc.Length == 0)
       return _error->Error(_("Failed to read .dsc"));
-   
+
    // Write back the control information
    InitQuerySource();
-   if (Put(Dsc.Data, Dsc.Length) == true)
+   if (Put(Dsc.Data.c_str(), Dsc.Length) == true)
       CurStat.Flags |= FlSource;
 
    return true;
diff --git a/ftparchive/sources.cc b/ftparchive/sources.cc
index d0878a70a..ab976b490 100644
--- a/ftparchive/sources.cc
+++ b/ftparchive/sources.cc
@@ -1,5 +1,5 @@
 #include <string>
-#include <iostream>
+#include <sstream>
 
 // for memcpy
 #include <cstring>
@@ -9,17 +9,19 @@
 
 #include "sources.h"
 
-bool DscExtract::TakeDsc(const void *newData, unsigned long newSize)
+bool DscExtract::TakeDsc(const void *newData, unsigned long long newSize)
 {
-   if(newSize > maxSize)
-     return _error->Error("DSC data is too large %lu!", newSize);
-
    if (newSize == 0)
    {
+      // adding two newlines 'off record' for pkgTagSection.Scan() calls
+      Data = "\n\n";
       Length = 0;
       return true;
    }
-   memcpy(Data, newData, newSize);
+
+   Data = std::string((const char*)newData, newSize);
+   // adding two newlines 'off record' for pkgTagSection.Scan() calls
+   Data.append("\n\n");
    Length = newSize;
 
    return true;
@@ -27,20 +29,31 @@ bool DscExtract::TakeDsc(const void *newData, unsigned long newSize)
 
 bool DscExtract::Read(std::string FileName)
 {
+   Data.clear();
+   Length = 0;
+
    FileFd F;
    if (OpenMaybeClearSignedFile(FileName, F) == false)
       return false;
-   
-   unsigned long long const FSize = F.FileSize();
-   if(FSize > maxSize)
-     return _error->Error("DSC file '%s' is too large!",FileName.c_str());
-
-   if (F.Read(Data, FSize) == false)
-      return false;
-   Length = FSize;
 
    IsClearSigned = (FileName != F.Name());
 
+   std::ostringstream data;
+   char buffer[1024];
+   do {
+      unsigned long long actual = 0;
+      if (F.Read(buffer, sizeof(buffer)-1, &actual) == false)
+	 return _error->Errno("read", "Failed to read dsc file %s", FileName.c_str());
+      if (actual == 0)
+	 break;
+      Length += actual;
+      buffer[actual] = '\0';
+      data << buffer;
+   } while(true);
+
+   // adding two newlines 'off record' for pkgTagSection.Scan() calls
+   data << "\n\n";
+   Data = data.str();
    return true;
 }
 
diff --git a/ftparchive/sources.h b/ftparchive/sources.h
index 91e0b1376..a125ec6a4 100644
--- a/ftparchive/sources.h
+++ b/ftparchive/sources.h
@@ -3,29 +3,21 @@
 
 #include <apt-pkg/tagfile.h>
 
-class DscExtract 
+#include <string>
+
+class DscExtract
 {
  public:
-   //FIXME: do we really need to enforce a maximum size of the dsc file?
-   static const int maxSize = 128*1024;
-
-   char *Data;
+   std::string Data;
    pkgTagSection Section;
-   unsigned long Length;
+   unsigned long long Length;
    bool IsClearSigned;
 
-   bool TakeDsc(const void *Data, unsigned long Size);
+   bool TakeDsc(const void *Data, unsigned long long Size);
    bool Read(std::string FileName);
-   
-   DscExtract() : Data(0), Length(0) {
-     Data = new char[maxSize];
-   };
-   ~DscExtract() { 
-      if(Data != NULL) {
-         delete [] Data;
-         Data = NULL;
-      } 
-   };
+
+   DscExtract() : Length(0), IsClearSigned(false) {};
+   ~DscExtract() {};
 };
 
 
diff --git a/ftparchive/writer.cc b/ftparchive/writer.cc
index 7c1c9cc03..0f6cc177b 100644
--- a/ftparchive/writer.cc
+++ b/ftparchive/writer.cc
@@ -634,18 +634,10 @@ bool SourcesWriter::DoPackage(string FileName)
    // the "db cursor"
    Db.Finish();
 
-   // read stuff
-   char *Start = Db.Dsc.Data;
-   char *BlkEnd = Db.Dsc.Data + Db.Dsc.Length;
-
-   // Add extra \n to the end, just in case (as in clearsigned they are missing)
-   *BlkEnd++ = '\n';
-   *BlkEnd++ = '\n';
-
    pkgTagSection Tags;
-   if (Tags.Scan(Start,BlkEnd - Start) == false)
+   if (Tags.Scan(Db.Dsc.Data.c_str(), Db.Dsc.Data.length()) == false)
       return _error->Error("Could not find a record in the DSC '%s'",FileName.c_str());
-   
+
    if (Tags.Exists("Source") == false)
       return _error->Error("Could not find a Source entry in the DSC '%s'",FileName.c_str());
    Tags.Trim();