ignore newlines in dpkg-deb control output for installing debs

Leading or trailing newlines can be confusing for our parser as it
expects two newlines to start/stop a new stanza. To solve this the lines
we wanna add are printed first, ignore any leading newlines and then add
the stanza as provided by dpkg-deb with or without trailing newlines as
the parser will look at the first stanza only anyway and removing
trailing newlines is considerably harder to do.

Closes: 802553

1 files changed, 13 insertions, 4 deletions

diff --git a/apt-pkg/deb/debindexfile.cc b/apt-pkg/deb/debindexfile.cc
index 793882e67..708b40a96 100644
--- a/apt-pkg/deb/debindexfile.cc
+++ b/apt-pkg/deb/debindexfile.cc
@@ -181,6 +181,9 @@ bool debDebPkgFileIndex::GetContent(std::ostream &content, std::string const &de
    if(Popen((const char**)&Args[0], PipeFd, Child, FileFd::ReadOnly) == false)
       return _error->Error("Popen failed");
 
+   content << "Filename: " << debfile << "\n";
+   content << "Size: " << Buf.st_size << "\n";
+   bool first_line_seen = false;
    char buffer[1024];
    do {
       unsigned long long actual = 0;
@@ -189,13 +192,19 @@ bool debDebPkgFileIndex::GetContent(std::ostream &content, std::string const &de
       if (actual == 0)
 	 break;
       buffer[actual] = '\0';
-      content << buffer;
+      char const * b = buffer;
+      if (first_line_seen == false)
+      {
+	 for (; *b != '\0' && (*b == '\n' || *b == '\r'); ++b)
+	    /* skip over leading newlines */;
+	 if (*b == '\0')
+	    continue;
+	 first_line_seen = true;
+      }
+      content << b;
    } while(true);
    ExecWait(Child, "Popen");
 
-   content << "Filename: " << debfile << "\n";
-   content << "Size: " << Buf.st_size << "\n";
-
    return true;
 }
 bool debDebPkgFileIndex::OpenListFile(FileFd &Pkg, std::string const &FileName)