Robustify accesses to server config

lib/defines.h

@@ -126,6 +126,7 @@ static inline void show_stackframe(){}
 
 #define SHM_STREAM_INDEX "MstSTRM%s" //%s stream name
 #define SHM_STREAM_STATE "MstSTATE%s" //%s stream name
+#define SHM_STREAM_CONF "MstSCnf%s" //%s stream name
 #define STRMSTAT_OFF 0
 #define STRMSTAT_INIT 1
 #define STRMSTAT_BOOT 2
@@ -139,11 +140,10 @@ static inline void show_stackframe(){}
 #define SHM_TRACK_DATA "MstDATA%s@%lu_%lu" //%s stream name, %lu track ID, %lu page #
 #define SHM_STATISTICS "MstSTAT"
 #define SHM_USERS "MstUSER%s" //%s stream name
-#define SHM_TRIGGER "MstTRIG%s" //%s trigger name
 #define SEM_LIVE "/MstLIVE%s" //%s stream name
 #define SEM_INPUT "/MstInpt%s" //%s stream name
-#define SEM_CONF "/MstConfLock"
+#define SHM_CAPA "MstCapa"
-#define SHM_CONF "MstConf"
+#define SHM_PROTO "MstProt"
 #define SHM_STATE_LOGS "MstStateLogs"
 #define SHM_STATE_ACCS "MstStateAccs"
 #define SHM_STATE_STREAMS "MstStateStreams"

lib/stream.cpp

@@ -79,20 +79,17 @@ JSON::Value Util::getStreamConfig(const std::string & streamname){
     FAIL_MSG("Stream opening denied: %s is longer than 100 characters (%lu).", streamname.c_str(), streamname.size());
     return result;
   }
-  IPC::sharedPage mistConfOut(SHM_CONF, DEFAULT_CONF_PAGE_SIZE, false, false);
-  IPC::semaphore configLock(SEM_CONF, O_CREAT | O_RDWR, ACCESSPERMS, 1);
-  configLock.wait();
-  DTSC::Scan config = DTSC::Scan(mistConfOut.mapped, mistConfOut.len);
   std::string smp = streamname.substr(0, streamname.find_first_of("+ "));
-  //check if smp (everything before + or space) exists
+
-  DTSC::Scan stream_cfg = config.getMember("streams").getMember(smp);
+  char tmpBuf[NAME_BUFFER_SIZE];
+  snprintf(tmpBuf, NAME_BUFFER_SIZE, SHM_STREAM_CONF, smp.c_str());
+  Util::DTSCShmReader rStrmConf(tmpBuf);
+  DTSC::Scan stream_cfg = rStrmConf.getScan();
   if (!stream_cfg){
-    DEBUG_MSG(DLVL_MEDIUM, "Stream %s not configured", streamname.c_str());
+    WARN_MSG("Could not get stream '%s' config!", smp.c_str());
-  }else{
-    result = stream_cfg.asJSON();
-  }
-  configLock.post();//unlock the config semaphore
     return result;
+  }
+  return stream_cfg.asJSON();
 }
 
 DTSC::Meta Util::getStreamMeta(const std::string & streamname){
@@ -281,22 +278,17 @@ JSON::Value Util::getInputBySource(const std::string &filename, bool isProvider)
   JSON::Value ret;
 
   //Attempt to load up configuration and find this stream
-  IPC::sharedPage mistConfOut(SHM_CONF, DEFAULT_CONF_PAGE_SIZE);
+  Util::DTSCShmReader rCapa(SHM_CAPA);
-  IPC::semaphore configLock(SEM_CONF, O_CREAT | O_RDWR, ACCESSPERMS, 1);
+  DTSC::Scan inputs = rCapa.getMember("inputs");
-  //Lock the config to prevent race conditions and corruption issues while reading
+  //Abort if not available
-  configLock.wait();
+  if (!inputs){
-  DTSC::Scan config = DTSC::Scan(mistConfOut.mapped, mistConfOut.len);
+    FAIL_MSG("Capabilities not available, aborting! Is MistController running?");
-  //Abort if no config available
-  if (!config){
-    FAIL_MSG("Configuration not available, aborting! Is MistController running?");
-    configLock.post();//unlock the config semaphore
     return false;
   }
 
-  //check in curConf for capabilities-inputs-<naam>-priority/source_match
+  //check in curConf for <naam>-priority/source_match
   bool selected = false;
   long long int curPrio = -1;
-  DTSC::Scan inputs = config.getMember("capabilities").getMember("inputs");
   DTSC::Scan input;
   unsigned int input_size = inputs.getSize();
   bool noProviderNoPick = false;
@@ -350,7 +342,6 @@ JSON::Value Util::getInputBySource(const std::string &filename, bool isProvider)
   }else{
     ret = input.asJSON();
   }
-  configLock.post();//unlock the config semaphore
   return ret;
 }
 
@@ -362,3 +353,18 @@ uint8_t Util::getStreamStatus(const std::string & streamname){
   return streamStatus.mapped[0];
 }
 
+Util::DTSCShmReader::DTSCShmReader(const std::string &pageName){
+  rPage.init(pageName, 0);
+  if (rPage){
+    rAcc = Util::RelAccX(rPage.mapped);
+  }
+}
+
+DTSC::Scan Util::DTSCShmReader::getMember(const std::string &indice){
+  return DTSC::Scan(rAcc.getPointer("dtsc_data"), rAcc.getSize("dtsc_data")).getMember(indice.c_str());
+}
+
+DTSC::Scan Util::DTSCShmReader::getScan(){
+  return DTSC::Scan(rAcc.getPointer("dtsc_data"), rAcc.getSize("dtsc_data"));
+}
+

lib/stream.h

@@ -6,6 +6,8 @@
 #include "socket.h"
 #include "json.h"
 #include "dtsc.h"
+#include "shared_memory.h"
+#include "util.h"
 
 namespace Util {
   std::string getTmpFolder();
@@ -16,5 +18,16 @@ namespace Util {
   JSON::Value getInputBySource(const std::string & filename, bool isProvider = false);
   DTSC::Meta getStreamMeta(const std::string & streamname);
   uint8_t getStreamStatus(const std::string & streamname);
+
+  class DTSCShmReader{
+    public:
+      DTSCShmReader(const std::string &pageName);
+      DTSC::Scan getMember(const std::string &indice);
+      DTSC::Scan getScan();
+    private:
+      IPC::sharedPage rPage;
+      Util::RelAccX rAcc;
+  };
+
 }
 

lib/util.cpp

@@ -6,6 +6,7 @@
 #include "defines.h"
 #include "timing.h"
 #include "procs.h"
+#include "dtsc.h"
 #include <errno.h> // errno, ENOENT, EEXIST
 #include <iostream>
 #include <iomanip>
@@ -564,6 +565,13 @@ namespace Util{
             r << std::endl;
             break;
           }
+          case RAX_DTSC:{
+            char * ptr = getPointer(it->first, i);
+            size_t sz = getSize(it->first, i);
+            r << std::endl;
+            r << DTSC::Scan(ptr, sz).toPrettyString(indent+6) << std::endl;
+            break;
+          }
           default: r << "[UNIMPLEMENTED]" << std::endl; break;
         }
       }

lib/util.h

@@ -74,6 +74,7 @@ namespace Util{
   #define RAX_RAW 0x40
   #define RAX_256RAW 0x44
   #define RAX_512RAW 0x45
+  #define RAX_DTSC 0x50
 
   /// Reliable Access class.
   /// Provides reliable access to memory data structures, using dynamic static offsets and a status

src/controller/controller.cpp

@@ -61,43 +61,28 @@ void createAccount(std::string account){
 }
 
 /// Status monitoring thread.
-/// Will check outputs, inputs and converters every five seconds
+/// Will check outputs, inputs and converters every three seconds
 void statusMonitor(void *np){
-  IPC::semaphore configLock(SEM_CONF, O_CREAT | O_RDWR, ACCESSPERMS, 1);
   Controller::loadActiveConnectors();
   while (Controller::conf.is_active){
     // this scope prevents the configMutex from being locked constantly
     {
       tthread::lock_guard<tthread::mutex> guard(Controller::configMutex);
-      bool changed = false;
       // checks online protocols, reports changes to status
-      changed |= Controller::CheckProtocols(Controller::Storage["config"]["protocols"],
+      if (Controller::CheckProtocols(Controller::Storage["config"]["protocols"],
-                                            Controller::capabilities);
+                                            Controller::capabilities)){
+        Controller::writeProtocols();
+      }
       // checks stream statuses, reports changes to status
-      changed |= Controller::CheckAllStreams(Controller::Storage["streams"]);
+      Controller::CheckAllStreams(Controller::Storage["streams"]);
-
-      // check if the config semaphore is stuck, by trying to lock it for 5 attempts of 1 second...
-      if (!configLock.tryWaitOneSecond() && !configLock.tryWaitOneSecond() &&
-          !configLock.tryWaitOneSecond() && !configLock.tryWaitOneSecond()){
-        // that failed. We now unlock it, no matter what - and print a warning that it was stuck.
-        WARN_MSG("Configuration semaphore was stuck. Force-unlocking it and re-writing config.");
-        changed = true;
     }
-      configLock.unlink();
+    Util::sleep(3000); // wait at least 3 seconds
-      configLock.open(SEM_CONF, O_CREAT | O_RDWR, ACCESSPERMS, 1);
-      if (changed || Controller::configChanged){
-        Controller::writeConfig();
-        Controller::configChanged = false;
-      }
-    }
-    Util::sleep(5000); // wait at least 5 seconds
   }
   if (Controller::restarting){
     Controller::prepareActiveConnectorsForReload();
   }else{
     Controller::prepareActiveConnectorsForShutdown();
   }
-  configLock.unlink();
 }
 
 static unsigned long mix(unsigned long a, unsigned long b, unsigned long c){
@@ -254,12 +239,9 @@ int main_loop(int argc, char **argv){
     Controller::conf.getOption("username", true)[0u] =
         Controller::Storage["config"]["controller"]["username"];
   }
-  {
-    IPC::semaphore configLock(SEM_CONF, O_CREAT | O_RDWR, ACCESSPERMS, 1);
-    configLock.unlink();
-  }
   Controller::writeConfig();
   Controller::checkAvailProtocols();
+  Controller::writeCapabilities();
   createAccount(Controller::conf.getString("account"));
   Controller::conf.activate(); // activate early, so threads aren't killed.
 

src/controller/controller_statistics.cpp

@@ -122,10 +122,6 @@ void Controller::SharedMemStats(void * config){
       statServer.parseEach(parseStatistics);
       if (firstRun){
         firstRun = false;
-        servUpOtherBytes = 0;
-        servDownOtherBytes = 0;
-        servUpBytes = 0;
-        servDownBytes = 0;
         for (std::map<std::string, struct streamTotals>::iterator it = streamStats.begin(); it != streamStats.end(); ++it){
           it->second.upBytes = 0;
           it->second.downBytes = 0;

src/controller/controller_storage.cpp

@@ -211,43 +211,93 @@ namespace Controller {
     }
   }
 
-  /// Writes the current config to shared memory to be used in other processes
+
-  void writeConfig(){
+  void writeCapabilities(){
-    static JSON::Value writeConf;
+    std::string temp = capabilities.toPacked();
-    bool changed = false;
+    static IPC::sharedPage mistCapaOut(SHM_CAPA, temp.size()+100, true, false);
+    if (!mistCapaOut.mapped){
+      FAIL_MSG("Could not open capabilities config for writing! Is shared memory enabled on your system?");
+      return;
+    }
+    Util::RelAccX A(mistCapaOut.mapped, false);
+    A.addField("dtsc_data", RAX_DTSC, temp.size());
+    // write config
+    memcpy(A.getPointer("dtsc_data"), temp.data(), temp.size());
+    A.setRCount(1);
+    A.setEndPos(1);
+    A.setReady();
+  }
+
+  void writeProtocols(){
+    static JSON::Value proto_written;
     std::set<std::string> skip;
     skip.insert("online");
     skip.insert("error");
-    if (!writeConf["config"].compareExcept(Storage["config"], skip)){
+    if (Storage["config"]["protocols"].compareExcept(proto_written, skip)){return;}
-      writeConf["config"].assignFrom(Storage["config"], skip);
+    proto_written.assignFrom(Storage["config"]["protocols"], skip);
-      VERYHIGH_MSG("Saving new config because of edit in server config structure");
+    std::string temp = proto_written.toPacked();
-      changed = true;
+    static IPC::sharedPage mistProtoOut(SHM_PROTO, temp.size()+100, true, false);
-    }
+    mistProtoOut.close();
-    if (!writeConf["streams"].compareExcept(Storage["streams"], skip)){
+    mistProtoOut.init(SHM_PROTO, temp.size()+100, true, false);
-      writeConf["streams"].assignFrom(Storage["streams"], skip);
+    if (!mistProtoOut.mapped){
-      VERYHIGH_MSG("Saving new config because of edit in streams");
+      FAIL_MSG("Could not open protocol config for writing! Is shared memory enabled on your system?");
-      changed = true;
-    }
-    if (writeConf["capabilities"] != capabilities){
-      writeConf["capabilities"] = capabilities;
-      VERYHIGH_MSG("Saving new config because of edit in capabilities");
-      changed = true;
-    }
-    if (!changed){return;}//cancel further processing if no changes
-
-    static IPC::sharedPage mistConfOut(SHM_CONF, DEFAULT_CONF_PAGE_SIZE, true);
-    if (!mistConfOut.mapped){
-      FAIL_MSG("Could not open config shared memory storage for writing! Is shared memory enabled on your system?");
       return;
     }
-    IPC::semaphore configLock(SEM_CONF, O_CREAT | O_RDWR, ACCESSPERMS, 1);
+    // write config
-    //lock semaphore
+    {
-    configLock.wait();
+      Util::RelAccX A(mistProtoOut.mapped, false);
-    //write config
+      A.addField("dtsc_data", RAX_DTSC, temp.size());
-    std::string temp = writeConf.toPacked();
+      // write config
-    memcpy(mistConfOut.mapped, temp.data(), std::min(temp.size(), (size_t)mistConfOut.len));
+      memcpy(A.getPointer("dtsc_data"), temp.data(), temp.size());
-    //unlock semaphore
+      A.setRCount(1);
-    configLock.post();
+      A.setEndPos(1);
+      A.setReady();
+    }
+  }
+
+  void writeStream(const std::string & sName, const JSON::Value & sConf){
+    static std::map<std::string, JSON::Value> writtenStrms;
+    static std::map<std::string, IPC::sharedPage> pages;
+    static std::set<std::string> skip;
+    if (!skip.size()){
+      skip.insert("online");
+      skip.insert("error");
+      skip.insert("name");
+    }
+    if (sConf.isNull()){
+      writtenStrms.erase(sName);
+      pages.erase(sName);
+      return;
+    }
+    if (!writtenStrms.count(sName) || !writtenStrms[sName].compareExcept(sConf, skip)){
+      writtenStrms[sName].assignFrom(sConf, skip);
+      IPC::sharedPage & P = pages[sName];
+      std::string temp = writtenStrms[sName].toPacked();
+      P.close();
+      char tmpBuf[NAME_BUFFER_SIZE];
+      snprintf(tmpBuf, NAME_BUFFER_SIZE, SHM_STREAM_CONF, sName.c_str());
+      P.init(tmpBuf, temp.size()+100, true, false);
+      if (!P){
+        writtenStrms.erase(sName);
+        pages.erase(sName);
+        return;
+      }
+      Util::RelAccX A(P.mapped, false);
+      A.addField("dtsc_data", RAX_DTSC, temp.size());
+      // write config
+      memcpy(A.getPointer("dtsc_data"), temp.data(), temp.size());
+      A.setRCount(1);
+      A.setEndPos(1);
+      A.setReady();
+    }
+  }
+
+  /// Writes the current config to shared memory to be used in other processes
+  void writeConfig(){
+    writeProtocols();
+    jsonForEach(Storage["streams"], it){
+      writeStream(it.key(), *it);
+    }
   }
   
 }

src/controller/controller_storage.h

@@ -32,5 +32,8 @@ namespace Controller {
   void initState();
   void deinitState(bool leaveBehind);
   void writeConfig();
+  void writeStream(const std::string & sName, const JSON::Value & sConf);
+  void writeCapabilities();
+  void writeProtocols();
 
 }

src/controller/controller_streams.cpp

@@ -148,6 +148,7 @@ namespace Controller {
         out[jit.key()]["name"] = jit.key();
         Log("STRM", std::string("New stream ") + jit.key());
       }
+      Controller::writeStream(jit.key(), out[jit.key()]);
     }
   }
 
@@ -240,6 +241,7 @@ namespace Controller {
     }
     Log("STRM", std::string("Deleted stream ") + name);
     out.removeMember(name);
+    Controller::writeStream(name, JSON::Value());//Null JSON value = delete
   }
 
 } //Controller namespace

src/input/input.cpp

@@ -298,10 +298,11 @@ namespace Mist {
   bool Input::isAlwaysOn(){
     bool ret = true;
     std::string strName = streamName.substr(0, (streamName.find_first_of("+ ")));
-    IPC::sharedPage serverCfg(SHM_CONF, DEFAULT_CONF_PAGE_SIZE, false, false); ///< Contains server configuration and capabilities
+
-    IPC::semaphore configLock(SEM_CONF, O_CREAT | O_RDWR, ACCESSPERMS, 1);
+    char tmpBuf[NAME_BUFFER_SIZE];
-    configLock.wait();
+    snprintf(tmpBuf, NAME_BUFFER_SIZE, SHM_STREAM_CONF, strName.c_str());
-    DTSC::Scan streamCfg = DTSC::Scan(serverCfg.mapped, serverCfg.len).getMember("streams").getMember(strName);
+    Util::DTSCShmReader rStrmConf(tmpBuf);
+    DTSC::Scan streamCfg = rStrmConf.getScan();
     if (streamCfg){
       if (!streamCfg.getMember("always_on") || !streamCfg.getMember("always_on").asBool()){
         ret = false;
@@ -311,7 +312,6 @@ namespace Mist {
       ret = false;
 #endif
     }
-    configLock.post();
     return ret;
   }
 

src/input/input_buffer.cpp

@@ -739,13 +739,11 @@ namespace Mist {
     std::string strName = config->getString("streamname");
     Util::sanitizeName(strName);
     strName = strName.substr(0, (strName.find_first_of("+ ")));
-    IPC::sharedPage serverCfg(SHM_CONF, DEFAULT_CONF_PAGE_SIZE, false, false); ///< Contains server configuration and capabilities
+
-    IPC::semaphore configLock(SEM_CONF, O_CREAT | O_RDWR, ACCESSPERMS, 1);
+    char tmpBuf[NAME_BUFFER_SIZE];
-    if (!configLock.tryWaitOneSecond()){
+    snprintf(tmpBuf, NAME_BUFFER_SIZE, SHM_STREAM_CONF, strName.c_str());
-      INFO_MSG("Aborting stream config refresh: locking took longer than expected");
+    Util::DTSCShmReader rStrmConf(tmpBuf);
-      return false;
+    DTSC::Scan streamCfg = rStrmConf.getScan();
-    }
-    DTSC::Scan streamCfg = DTSC::Scan(serverCfg.mapped, serverCfg.len).getMember("streams").getMember(strName);
     long long tmpNum;
 
     //if stream is configured and setting is present, use it, always

src/output/output_http.cpp

@@ -123,10 +123,8 @@ namespace Mist {
     }
     
     //loop over the connectors
-    IPC::semaphore configLock(SEM_CONF, O_CREAT | O_RDWR, ACCESSPERMS, 1);
+    Util::DTSCShmReader rCapa(SHM_CAPA);
-    configLock.wait();
+    DTSC::Scan capa = rCapa.getMember("connectors");
-    IPC::sharedPage serverCfg(SHM_CONF, DEFAULT_CONF_PAGE_SIZE);
-    DTSC::Scan capa = DTSC::Scan(serverCfg.mapped, serverCfg.len).getMember("capabilities").getMember("connectors");
     unsigned int capa_ctr = capa.getSize();
     for (unsigned int i = 0; i < capa_ctr; ++i){
       DTSC::Scan c = capa.getIndice(i);
@@ -159,14 +157,10 @@ namespace Mist {
             Util::sanitizeName(streamname);
             H.SetVar("stream", streamname);
           }
-          configLock.post();
-          configLock.close();
           return capa.getIndiceName(i);
         }
       }
     }
-    configLock.post();
-    configLock.close();
     return "";
   }
   
@@ -323,14 +317,16 @@ namespace Mist {
     char * argarr[20];
     for (int i=0; i<20; i++){argarr[i] = 0;}
     int id = -1;
+    JSON::Value pipedCapa;
+    JSON::Value p;//properties of protocol
     
-    IPC::semaphore configLock(SEM_CONF, O_CREAT | O_RDWR, ACCESSPERMS, 1);
+
-    configLock.wait();
+    {
-    IPC::sharedPage serverCfg(SHM_CONF, DEFAULT_CONF_PAGE_SIZE);
+      Util::DTSCShmReader rProto(SHM_PROTO);
-    DTSC::Scan prots = DTSC::Scan(serverCfg.mapped, serverCfg.len).getMember("config").getMember("protocols");
+      DTSC::Scan prots = rProto.getScan();
       unsigned int prots_ctr = prots.getSize();
      
-    JSON::Value p;//properties of protocol
+      //find connector in config
       for (unsigned int i=0; i < prots_ctr; ++i){
         if (prots.getIndice(i).getMember("connector").asString() == connector) {
           id =  i;
@@ -347,25 +343,23 @@ namespace Mist {
         }
         if (id == -1) {
           connector = connector.substr(0, connector.size() - 4);
-        DEBUG_MSG(DLVL_ERROR, "No connector found for: %s", connector.c_str());
+          ERROR_MSG("No connector found for: %s", connector.c_str());
-        configLock.post();
-        configLock.close();
           return;
         }
       }
       //read options from found connector
       p = prots.getIndice(id).asJSON();
       
-    DEBUG_MSG(DLVL_HIGH, "Connector found: %s", connector.c_str());
+      HIGH_MSG("Connector found: %s", connector.c_str());
+      Util::DTSCShmReader rCapa(SHM_CAPA);
+      DTSC::Scan capa = rCapa.getMember("connectors");
+      pipedCapa = capa.getMember(connector).asJSON();
+    }
+
     //build arguments for starting output process
-    
     std::string tmparg = Util::getMyPath() + std::string("MistOut") + connector;
-    
     int argnum = 0;
     argarr[argnum++] = (char*)tmparg.c_str();
-    JSON::Value pipedCapa = DTSC::Scan(serverCfg.mapped, serverCfg.len).getMember("capabilities").getMember("connectors").getMember(connector).asJSON();
-    configLock.post();
-    configLock.close();
     std::string temphost=getConnectedHost();
     std::string debuglevel = JSON::Value((long long)Util::Config::printDebugLevel).asString();
     argarr[argnum++] = (char*)"--ip";

src/output/output_http_internal.cpp

@@ -11,13 +11,13 @@ namespace Mist {
   /// Helper function to find the protocol entry for a given port number
   std::string getProtocolForPort(uint16_t portNo){
     std::string ret;
-    IPC::semaphore configLock(SEM_CONF, O_CREAT | O_RDWR, ACCESSPERMS, 1);
+    Util::DTSCShmReader rCapa(SHM_CAPA);
-    configLock.wait();
+    DTSC::Scan conns = rCapa.getMember("connectors");
-    IPC::sharedPage serverCfg(SHM_CONF, DEFAULT_CONF_PAGE_SIZE);
+    Util::DTSCShmReader rProto(SHM_PROTO);
-    DTSC::Scan prtcls = DTSC::Scan(serverCfg.mapped, serverCfg.len).getMember("config").getMember("protocols");
+    DTSC::Scan prtcls = rProto.getScan();
     unsigned int pro_cnt = prtcls.getSize();
     for (unsigned int i = 0; i < pro_cnt; ++i){
-      DTSC::Scan capa = DTSC::Scan(serverCfg.mapped, serverCfg.len).getMember("capabilities").getMember("connectors").getMember(prtcls.getIndice(i).getMember("connector").asString());
+      DTSC::Scan capa = conns.getMember(prtcls.getIndice(i).getMember("connector").asString());
       uint16_t port = prtcls.getIndice(i).getMember("port").asInt();
       //get the default port if none is set
       if (!port){
@@ -28,7 +28,6 @@ namespace Mist {
         break;
       }
     }
-    configLock.post();
     if (ret.find(':') != std::string::npos){
       ret.erase(ret.find(':'));
     }
@@ -348,16 +347,6 @@ namespace Mist {
     if (!myConn){
       return json_resp;
     }
-    IPC::semaphore configLock(SEM_CONF, O_CREAT | O_RDWR, ACCESSPERMS, 1);
-    configLock.wait();
-    IPC::sharedPage serverCfg(SHM_CONF, DEFAULT_CONF_PAGE_SIZE);
-    DTSC::Scan prots = DTSC::Scan(serverCfg.mapped, serverCfg.len).getMember("config").getMember("protocols");
-    if (!prots){
-      json_resp["error"] = "The specified stream is not available on this server.";
-      configLock.post();
-      configLock.close();
-      return json_resp;
-    }
 
     bool hasVideo = false;
     for (std::map<unsigned int, DTSC::Track>::iterator trit = myMeta.tracks.begin(); trit != myMeta.tracks.end(); trit++){
@@ -396,6 +385,16 @@ namespace Mist {
     }
     json_resp["meta"].removeMember("source");
 
+    //Get sources/protocols information
+    Util::DTSCShmReader rCapa(SHM_CAPA);
+    DTSC::Scan connectors = rCapa.getMember("connectors");
+    Util::DTSCShmReader rProto(SHM_PROTO);
+    DTSC::Scan prots = rProto.getScan();
+    if (!prots || !connectors){
+      json_resp["error"] = "Server configuration unavailable at this time.";
+      return json_resp;
+    }
+ 
     //create a set for storing source information
     std::set<JSON::Value, sourceCompare> sources;
     
@@ -408,7 +407,7 @@ namespace Mist {
     //loop over the connectors.
     for (unsigned int i = 0; i < prots_ctr; ++i){
       std::string cName = prots.getIndice(i).getMember("connector").asString();
-      DTSC::Scan capa = DTSC::Scan(serverCfg.mapped, serverCfg.len).getMember("capabilities").getMember("connectors").getMember(cName);
+      DTSC::Scan capa = connectors.getMember(cName);
       //if the connector has a port,
       if (capa.getMember("optional").getMember("port")){
         HTTP::URL outURL(reqHost);
@@ -431,12 +430,11 @@ namespace Mist {
           std::string cProv = capa.getMember("provides").asString();
           //if this connector can be depended upon by other connectors, loop over the rest
           //check each enabled protocol separately to see if it depends on this connector
-          DTSC::Scan capa_lst = DTSC::Scan(serverCfg.mapped, serverCfg.len).getMember("capabilities").getMember("connectors");
+          unsigned int capa_lst_ctr = connectors.getSize();
-          unsigned int capa_lst_ctr = capa_lst.getSize();
           for (unsigned int j = 0; j < capa_lst_ctr; ++j){
             //if it depends on this connector and has a URL, list it
-            if (conns.count(capa_lst.getIndiceName(j)) && capa_lst.getIndice(j).getMember("deps").asString() == cProv && capa_lst.getIndice(j).getMember("methods")){
+            if (conns.count(connectors.getIndiceName(j)) && connectors.getIndice(j).getMember("deps").asString() == cProv && connectors.getIndice(j).getMember("methods")){
-              JSON::Value subcapa_json = capa_lst.getIndice(j).asJSON();
+              JSON::Value subcapa_json = connectors.getIndice(j).asJSON();
               addSources(streamName, sources, outURL, subcapa_json, json_resp["meta"], useragent);
             }
           }
@@ -450,8 +448,6 @@ namespace Mist {
         json_resp["source"].append(*it);
       }
     }
-    configLock.post();
-    configLock.close();
     return json_resp;
   }
 
@@ -522,14 +518,13 @@ namespace Mist {
     // send smil MBR index
     if (H.url.length() > 6 && H.url.substr(H.url.length() - 5, 5) == ".smil"){
       std::string reqHost = HTTP::URL(H.GetHeader("Host")).host;
-      
       std::string port, url_rel;
-      
+      std::string trackSources;//this string contains all track sources for MBR smil
-      IPC::semaphore configLock(SEM_CONF, O_CREAT | O_RDWR, ACCESSPERMS, 1);
+      {
-      configLock.wait();
+        Util::DTSCShmReader rProto(SHM_PROTO);
-      IPC::sharedPage serverCfg(SHM_CONF, DEFAULT_CONF_PAGE_SIZE);
+        DTSC::Scan prtcls = rProto.getScan();
-      DTSC::Scan prtcls = DTSC::Scan(serverCfg.mapped, serverCfg.len).getMember("config").getMember("protocols");
+        Util::DTSCShmReader rCapa(SHM_CAPA);
-      DTSC::Scan capa = DTSC::Scan(serverCfg.mapped, serverCfg.len).getMember("capabilities").getMember("connectors").getMember("RTMP");
+        DTSC::Scan capa = rCapa.getMember("connectors").getMember("RTMP");
         unsigned int pro_cnt = prtcls.getSize();
         for (unsigned int i = 0; i < pro_cnt; ++i){
           if (prtcls.getIndice(i).getMember("connector").asString() != "RTMP"){
@@ -547,7 +542,6 @@ namespace Mist {
           }
         }
         
-      std::string trackSources;//this string contains all track sources for MBR smil
         initialize();
         if (!myConn){return;}
         for (std::map<unsigned int, DTSC::Track>::iterator trit = myMeta.tracks.begin(); trit != myMeta.tracks.end(); trit++){
@@ -555,8 +549,7 @@ namespace Mist {
             trackSources += "      <video src='"+ streamName + "?track=" + JSON::Value((long long)trit->first).asString() + "' height='" + JSON::Value((long long)trit->second.height).asString() + "' system-bitrate='" + JSON::Value((long long)trit->second.bps).asString() + "' width='" + JSON::Value((long long)trit->second.width).asString() + "' />\n";
           }
         }
-      configLock.post();
+      }
-      configLock.close();
       
       H.Clean();
       H.SetHeader("Content-Type", "application/smil");