Add ability to SCR component to operate on different root

Before, the `scr` component was common agent server component. There is also scr
server program located at `/usr/share/YaST2/servers/scr`, that allows to call
scr as external program in chroot via ProgramCompnent.
Now to remove the need for `chroot(2)`, scr component can be instantiated with
target root, which is propagated to whole scr agent tree. It require API changes
because common SCRAgent template doesn't fit there.

agent-ini/testsuite/runag_ini.cc

@@ -27,7 +27,7 @@ main (int argc, char *argv[])
 	scrconf.replace (p, 4, ".scr");
     }
 
-    SCRAgent *agent = new ScriptingAgent (scrconf);
+    SCRAgent *agent = new ScriptingAgent ("/", scrconf);
     if (!agent)
     {
 	fprintf (stderr, "Failed to create Agent\n");

libscr/src/include/scr/Y2AgentComponent.h

@@ -36,26 +36,26 @@ template <class Agent> class Y2AgentComp : public Y2Component
     /**
      * Clean up.
      */
-    ~Y2AgentComp ();
+    virtual ~Y2AgentComp ();
 
     /**
      * Returns the name of the component.
      */
-    string name () const { return my_name; }
+    virtual string name () const { return my_name; }
 
     /**
      * Evaluates a command to the agent.
      */
-    YCPValue evaluate (const YCPValue &command);
+    virtual YCPValue evaluate (const YCPValue &command);
 
     /**
      * Returns the SCRAgent of the Y2Component.
      */
-    SCRAgent* getSCRAgent ();
+    virtual SCRAgent* getSCRAgent ();
 
-    YCPValue Read (const YCPPath &path);
-    
-private:
+    virtual YCPValue Read (const YCPPath &path);
+
+protected:
 
     /**
      * Name of my agent.

scr/src/Makefile.am

@@ -9,7 +9,8 @@ serversdir = $(execcompdir)/servers
 plugin_LTLIBRARIES = libpy2scr.la
 
 libpy2scr_la_SOURCES =				\
-	Y2CCSCR.cc				\
+	Y2CCSCR.cc Y2CCSCR.h				\
+	Y2SCRComponent.cc Y2SCRComponent.h	\
 	ScriptingAgent.cc ScriptingAgent.h	\
 	StdioSCRAgent.cc StdioSCRAgent.h	\
 	SCRSubAgent.cc SCRSubAgent.h

scr/src/ScriptingAgent.cc

@@ -25,8 +25,9 @@
 #include "ScriptingAgent.h"
 
 
-ScriptingAgent::ScriptingAgent ()
-    : done_sweep (false)
+ScriptingAgent::ScriptingAgent (const string &root_)
+    : done_sweep (false),
+      root_path(root_)
 {
     InitRegDirs ();
     // to test the old behavior
@@ -35,8 +36,9 @@ ScriptingAgent::ScriptingAgent ()
 }
 
 
-ScriptingAgent::ScriptingAgent (const string& file)
-    : done_sweep (false)
+ScriptingAgent::ScriptingAgent (const string &root_, const string& file)
+    : done_sweep (false),
+      root_path(root_)
 {
     InitRegDirs ();
     y2debug( "Scripting agent using only SCR %s", file.c_str () );
@@ -74,6 +76,11 @@ ScriptingAgent::~ScriptingAgent ()
     UnregisterAllAgents ();
 }
 
+const char* ScriptingAgent::root() const
+{
+    return root_path.c_str();
+}
+
 bool less_than_inodes (const pair<ino_t, string>& a,
 		       const pair<ino_t, string>& b)
 {

scr/src/ScriptingAgent.h

@@ -27,7 +27,7 @@ class ScriptingAgent : public SCRAgent
     /**
      * Constructor.
      */
-    ScriptingAgent ();
+    ScriptingAgent (const string& root = "/");
 
     // used only in agent-ini/testsuite...?
     // TODO try to eliminate it
@@ -36,13 +36,19 @@ class ScriptingAgent : public SCRAgent
      * 
      * @param file	SCR configuration file to be registered.
      */
-    ScriptingAgent (const string& file);
+    ScriptingAgent (const string& root, const string& file);
 
     /**
      * Destructor. Also deletes subagents.
      */
     ~ScriptingAgent ();
 
+    /**
+     * Overrides root getter to provide root from constructor
+     * \see SCRAgent#root
+     */
+    virtual const char* root() const;
+
     /**
      * Reads data.
      * @param path Specifies what part of the subtree should
@@ -123,6 +129,8 @@ class ScriptingAgent : public SCRAgent
     // that we do not unnecessarily sweep again
     bool done_sweep;
 
+    string root_path;
+
     // FIXME rethink the caching
     struct RegistrationDir {
 	string name;

scr/src/Y2CCSCR.cc

@@ -5,15 +5,56 @@
  */
 
 
-#include <scr/Y2AgentComponent.h>
-#include <scr/Y2CCAgentComponent.h>
+#include "Y2CCSCR.h"
+#include "Y2SCRComponent.h"
 
-#include "ScriptingAgent.h"
+using namespace std;
 
+Y2CCSCR::Y2CCSCR () :
+  Y2ComponentCreator (Y2ComponentBroker::BUILTIN)
+{ 
+}
 
-// create Agent called Y2SCRComp out of ScriptingAgent
-typedef Y2AgentComp <ScriptingAgent> Y2SCRComp;
+Y2CCSCR::~Y2CCSCR () { 
+    for (map<string, Y2SCRComponent*>::iterator i = scr_instances.begin();
+        i != scr_instances.end(); ++i)
+      delete i->second;
+}
 
-// create Component Creator for Y2SCRComp
-Y2CCAgentComp <Y2SCRComp> g_y2ccscr ("scr");
+/* local helper for CC#create */
+static void split_name( const char *name, string &root, string &real_name)
+{
+    real_name = name;
+    root = "/";
+
+    if (strncmp (name, "chroot=", 7) == 0)
+    {
+      const char *p = index (name, ':');
+
+      if (p) {
+        root = string (name, 7, p - name - 7);
+        real_name = string (p + 1);
+      }
+    }
+}
+
+Y2Component *Y2CCSCR::create( const char* name) const
+{
+    string root, real_name;
+
+    split_name(name, root, real_name);
 
+    if (real_name != "scr")
+        return NULL;
+
+    map<string, Y2SCRComponent*>::iterator i = scr_instances.find(root);
+    if (i != scr_instances.end())
+        return i->second;
+
+    scr_instances[root] = new Y2SCRComponent(root.c_str());
+	  return scr_instances[root];
+}
+
+
+// create Component Creator for Y2SCRComp
+Y2CCSCR g_y2ccscr;

scr/src/Y2CCSCR.h

@@ -0,0 +1,50 @@
+#ifndef Y2CCSCR_H
+#define Y2CCSCR_H
+
+#include <y2/Y2ComponentCreator.h>
+#include <map>
+#include <string>
+
+#include "ScriptingAgent.h"
+#include "Y2SCRComponent.h"
+
+class Y2CCSCR : public Y2ComponentCreator
+{
+public:
+
+    /**
+     * Constructor of a SCR component creator.
+     */
+    Y2CCSCR ();
+
+
+    /**
+     * Destructor of a SCR component creator.
+     */
+    ~Y2CCSCR ();
+
+
+    /**
+     * Returns true since all agents are server components.
+     */
+    bool isServerCreator () const { return true; }
+
+    /**
+     * Creates a new @ref Y2Component if the name matches the one
+     * provided in the constructor.
+     */
+    Y2Component* create (const char*) const;
+
+    /**
+     * Agent components do not provide any namespaces.
+     */
+    Y2Component* provideNamespace (const char*) { return NULL; }
+
+private:
+
+    /* SCR instances, owned by this class, keyed by target root.
+     * Target root must be valid absolute path like "/" or "/mnt".*/
+    mutable std::map<std::string, Y2SCRComponent*> scr_instances;
+};
+
+#endif

scr/src/Y2SCRComponent.cc

@@ -0,0 +1,14 @@
+#include "Y2SCRComponent.h"
+#include "ScriptingAgent.h"
+
+
+Y2SCRComponent::Y2SCRComponent(const char *root) :
+  Y2AgentComp<ScriptingAgent>("scr")
+{
+  agent = new ScriptingAgent(root);
+}
+
+Y2SCRComponent::~Y2SCRComponent()
+{
+  //agent is destructed in parent
+}

scr/src/Y2SCRComponent.h

@@ -0,0 +1,15 @@
+#ifndef Y2SCRCOMPONENT_H
+#define Y2SCRCOMPONENT_H
+
+#include <scr/Y2AgentComponent.h>
+#include "ScriptingAgent.h"
+
+class Y2SCRComponent : public Y2AgentComp<ScriptingAgent>
+{
+public:
+  Y2SCRComponent(const char* root);
+
+  ~Y2SCRComponent();
+};
+
+#endif