drop privileges in copy:// method as we do for file://

Continueing on the track of dropping privileges in all methods, lets
drop it in copy, too, as the reasoning for it is very similar to file
and the interaction between the too quiet interesting as copy kinda
surfed as a fallback for file not being able to read the file. Both now
show a better error message as well as it was previously claiming to
have a hashsum mismatch, given that it couldn't read the file.

Git-Dch: Ignore

3 files changed, 54 insertions, 38 deletions

diff --git a/methods/aptmethod.h b/methods/aptmethod.h
new file mode 100644
index 000000000..61d7b78f1
--- /dev/null
+++ b/methods/aptmethod.h
@@ -0,0 +1,37 @@
+#ifndef APT_APTMETHOD_H
+#define APT_APTMETHOD_H
+
+#include <apt-pkg/acquire-method.h>
+
+#include <string>
+
+class aptMethod : public pkgAcqMethod
+{
+   char const * const Binary;
+   public:
+   virtual bool Configuration(std::string Message) APT_OVERRIDE;
+
+   bool CalculateHashes(FetchItem const * const Itm, FetchResult &Res) const;
+
+   aptMethod(char const * const Binary, char const * const Ver, unsigned long const Flags) : pkgAcqMethod(Ver, Flags), Binary(Binary) {};
+};
+bool aptMethod::Configuration(std::string Message)
+{
+   if (pkgAcqMethod::Configuration(Message) == false)
+      return false;
+
+   DropPrivsOrDie();
+
+   return true;
+}
+bool aptMethod::CalculateHashes(FetchItem const * const Itm, FetchResult &Res) const
+{
+   Hashes Hash(Itm->ExpectedHashes);
+   FileFd Fd;
+   if (Fd.Open(Res.Filename, FileFd::ReadOnly) == false || Hash.AddFD(Fd) == false)
+      return false;
+   Res.TakeHashes(Hash);
+   return true;
+}
+
+#endif
diff --git a/methods/copy.cc b/methods/copy.cc
index 373ad3604..e515b2def 100644
--- a/methods/copy.cc
+++ b/methods/copy.cc
@@ -17,6 +17,7 @@
 #include <apt-pkg/error.h>
 #include <apt-pkg/hashes.h>
 #include <apt-pkg/configuration.h>
+#include "aptmethod.h"
 
 #include <string>
 #include <sys/stat.h>
@@ -25,23 +26,14 @@
 #include <apti18n.h>
 									/*}}}*/
 
-class CopyMethod : public pkgAcqMethod
+class CopyMethod : public aptMethod
 {
    virtual bool Fetch(FetchItem *Itm) APT_OVERRIDE;
-   void CalculateHashes(FetchItem const * const Itm, FetchResult &Res);
-   
+
    public:
-   
-   CopyMethod() : pkgAcqMethod("1.0",SingleInstance | SendConfig) {};
-};
 
-void CopyMethod::CalculateHashes(FetchItem const * const Itm, FetchResult &Res)
-{
-   Hashes Hash(Itm->ExpectedHashes);
-   FileFd Fd(Res.Filename, FileFd::ReadOnly);
-   Hash.AddFD(Fd);
-   Res.TakeHashes(Hash);
-}
+   CopyMethod() : aptMethod("copy", "1.0",SingleInstance | SendConfig) {};
+};
 
 // CopyMethod::Fetch - Fetch a file					/*{{{*/
 // ---------------------------------------------------------------------
@@ -76,12 +68,7 @@ bool CopyMethod::Fetch(FetchItem *Itm)
    FileFd From(File,FileFd::ReadOnly);
    FileFd To(Itm->DestFile,FileFd::WriteAtomic);
    To.EraseOnFailure();
-   if (_error->PendingError() == true)
-   {
-      To.OpFail();
-      return false;
-   }
-   
+
    // Copy the file
    if (CopyFile(From,To) == false)
    {
@@ -101,7 +88,6 @@ bool CopyMethod::Fetch(FetchItem *Itm)
       return _error->Errno("utimes",_("Failed to set modification time"));
 
    CalculateHashes(Itm, Res);
-
    URIDone(Res);
    return true;
 }
diff --git a/methods/file.cc b/methods/file.cc
index 8a087c36d..4e3410078 100644
--- a/methods/file.cc
+++ b/methods/file.cc
@@ -21,6 +21,7 @@
 #include <apt-pkg/hashes.h>
 #include <apt-pkg/fileutl.h>
 #include <apt-pkg/strutl.h>
+#include "aptmethod.h"
 
 #include <string>
 #include <sys/stat.h>
@@ -28,24 +29,13 @@
 #include <apti18n.h>
 									/*}}}*/
 
-class FileMethod : public pkgAcqMethod
+class FileMethod : public aptMethod
 {
    virtual bool Fetch(FetchItem *Itm) APT_OVERRIDE;
-   virtual bool Configuration(std::string Message) APT_OVERRIDE;
 
    public:
-
-   FileMethod() : pkgAcqMethod("1.0",SingleInstance | SendConfig | LocalOnly) {};
+   FileMethod() : aptMethod("file", "1.0", SingleInstance | SendConfig | LocalOnly) {};
 };
-bool FileMethod::Configuration(std::string Message)
-{
-   if (pkgAcqMethod::Configuration(Message) == false)
-      return false;
-
-   DropPrivsOrDie();
-
-   return true;
-}
 
 // FileMethod::Fetch - Fetch a file					/*{{{*/
 // ---------------------------------------------------------------------
@@ -78,6 +68,7 @@ bool FileMethod::Fetch(FetchItem *Itm)
    if (Res.IMSHit != true)
       RemoveFile("file", Itm->DestFile);
 
+   int olderrno = 0;
    // See if the file exists
    if (stat(File.c_str(),&Buf) == 0)
    {
@@ -92,11 +83,10 @@ bool FileMethod::Fetch(FetchItem *Itm)
 	    Res.IMSHit = true;
       }
 
-      Hashes Hash(Itm->ExpectedHashes);
-      FileFd Fd(File, FileFd::ReadOnly);
-      Hash.AddFD(Fd);
-      Res.TakeHashes(Hash);
+      CalculateHashes(Itm, Res);
    }
+   else
+      olderrno = errno;
    if (Res.IMSHit == false)
       URIStart(Res);
 
@@ -128,7 +118,10 @@ bool FileMethod::Fetch(FetchItem *Itm)
    else if (Res.Filename.empty() == false)
       URIDone(Res);
    else
-      return _error->Error(_("File not found"));
+   {
+      errno = olderrno;
+      return _error->Errno(File.c_str(), _("File not found"));
+   }
 
    return true;
 }