- add method to open (maybe) clearsigned files transparently

* ftparchive/writer.cc:
  - use OpenMaybeClearSignedFile to be free from detecting and
    skipping clearsigning metadata in dsc files

2 files changed, 76 insertions, 1 deletions

diff --git a/apt-pkg/contrib/gpgv.cc b/apt-pkg/contrib/gpgv.cc
index 5921d7c67..fc16dd32c 100644
--- a/apt-pkg/contrib/gpgv.cc
+++ b/apt-pkg/contrib/gpgv.cc
@@ -19,7 +19,7 @@
 
 #include <apti18n.h>
 									/*}}}*/
-char * GenerateTemporaryFileTemplate(const char *basename)		/*{{{*/
+static char * GenerateTemporaryFileTemplate(const char *basename)	/*{{{*/
 {
    const char *tmpdir = getenv("TMPDIR");
 #ifdef P_tmpdir
@@ -376,5 +376,58 @@ bool SplitClearSignedFile(std::string const &InFile, int const ContentFile,
       fclose(out_signature);
    fclose(in);
 
+   if (found_signature == true)
+      return _error->Error("Signature in file %s wasn't closed", InFile.c_str());
+
+   // if we haven't found any of them, this an unsigned file,
+   // so don't generate an error, but splitting was unsuccessful none-the-less
+   if (found_message_start == false && found_message_end == false)
+      return false;
+   // otherwise one missing indicates a syntax error
+   else if (found_message_start == false || found_message_end == false)
+      return _error->Error("Splitting of file %s failed as it doesn't contain all expected parts", InFile.c_str());
+
    return true;
 }
+									/*}}}*/
+bool OpenMaybeClearSignedFile(std::string const &ClearSignedFileName, FileFd &MessageFile) /*{{{*/
+{
+   char * const message = GenerateTemporaryFileTemplate("fileutl.message");
+   int const messageFd = mkstemp(message);
+   if (messageFd == -1)
+   {
+      free(message);
+      return _error->Errno("mkstemp", "Couldn't create temporary file to work with %s", ClearSignedFileName.c_str());
+   }
+   // we have the fd, thats enough for us
+   unlink(message);
+   free(message);
+
+   int const duppedMsg = dup(messageFd);
+   if (duppedMsg == -1)
+      return _error->Errno("dup", "Couldn't duplicate FD to work with %s", ClearSignedFileName.c_str());
+
+   _error->PushToStack();
+   bool const splitDone = SplitClearSignedFile(ClearSignedFileName.c_str(), messageFd, NULL, -1);
+   bool const errorDone = _error->PendingError();
+   _error->MergeWithStack();
+   if (splitDone == false)
+   {
+      close(duppedMsg);
+
+      if (errorDone == true)
+	 return false;
+
+      // we deal with an unsigned file
+      MessageFile.Open(ClearSignedFileName, FileFd::ReadOnly);
+   }
+   else // clear-signed
+   {
+      if (lseek(duppedMsg, 0, SEEK_SET) < 0)
+	 return _error->Errno("lseek", "Unable to seek back in message fd for file %s", ClearSignedFileName.c_str());
+      MessageFile.OpenDescriptor(duppedMsg, FileFd::ReadOnly, true);
+   }
+
+   return MessageFile.Failed() == false;
+}
+									/*}}}*/
diff --git a/apt-pkg/contrib/gpgv.h b/apt-pkg/contrib/gpgv.h
index 8e04855e4..ab7d35ab1 100644
--- a/apt-pkg/contrib/gpgv.h
+++ b/apt-pkg/contrib/gpgv.h
@@ -12,6 +12,8 @@
 #include <string>
 #include <vector>
 
+#include <apt-pkg/fileutl.h>
+
 #if __GNUC__ >= 4
 	#define APT_noreturn	__attribute__ ((noreturn))
 #else
@@ -52,10 +54,17 @@ inline void ExecGPGV(std::string const &File, std::string const &FileSig,
  *  The code doesn't support dash-encoded lines as these are not
  *  expected to be present in files we have to deal with.
  *
+ *  The content of the split files is undefined if the splitting was
+ *  unsuccessful.
+ *
+ *  Note that trying to split an unsigned file will fail, but
+ *  not generate an error message.
+ *
  *  @param InFile is the clear-signed file
  *  @param ContentFile is the Fd the message will be written to
  *  @param ContentHeader is a list of all required Amored Headers for the message
  *  @param SignatureFile is the Fd all signatures will be written to
+ *  @return true if the splitting was successful, false otherwise
  */
 bool SplitClearSignedFile(std::string const &InFile, int const ContentFile,
       std::vector<std::string> * const ContentHeader, int const SignatureFile);
@@ -74,4 +83,17 @@ bool SplitClearSignedFile(std::string const &InFile, int const ContentFile,
 bool RecombineToClearSignedFile(std::string const &OutFile, int const ContentFile,
       std::vector<std::string> const &ContentHeader, int const SignatureFile);
 
+/** \brief open a file which might be clear-signed
+ *
+ * This method tries to extract the (signed) message of a file.
+ * If the file isn't signed it will just open the given filename.
+ * Otherwise the message is extracted to a temporary file which
+ * will be opened instead.
+ *
+ * @param ClearSignedFileName is the name of the file to open
+ * @param[out] MessageFile is the FileFd in which the file will be opened
+ * @return true if opening was successful, otherwise false
+ */
+bool OpenMaybeClearSignedFile(std::string const &ClearSignedFileName, FileFd &MessageFile);
+
 #endif