Fixes: NB#273378 - Boosters should restore original signal handlers modified by applauncherd

RevBy: Dmitry Rozenshtein, Pertti Kellomaki

debian/changelog

@@ -2,6 +2,7 @@ applauncherd (1.1.0) unstable; urgency=low
 
   * Fixes: NB#262604 - applauncherd not buildable with eglibc 2.12
   * Fixes: NB#248543 - [SSU]:Error seen at 'invoker: error: Can't send signal to application: No such process '
+  * Fixes: NB#273378 - Boosters should restore original signal handlers modified by applauncherd
 
  -- Juha Lintula <juha.lintula@nokia.com>  Tue, 14 Jun 2011 14:55:06 +0300
 

src/launcherlib/daemon.cpp

@@ -405,12 +405,8 @@ void Daemon::forkBooster(char type, int sleepTime)
 
     if (newPid == 0) /* Child process */
     {
-        // Reset used signal handlers
-        signal(SIGCHLD, SIG_DFL);
-        signal(SIGTERM, SIG_DFL);
-        signal(SIGUSR1, SIG_DFL);
-        signal(SIGUSR2, SIG_DFL);
-        signal(SIGPIPE, SIG_DFL);
+        // Restore used signal handlers
+        restoreUnixSignalHandlers();
 
         // Will get this signal if applauncherd dies
         prctl(PR_SET_PDEATHSIG, SIGHUP);
@@ -767,6 +763,33 @@ void Daemon::killBoosters()
     // in order to automatically start new boosters.
 }
 
+void Daemon::setUnixSignalHandler(int signum, sighandler_t handler)
+{
+    struct sigaction *oldAct = new struct sigaction();
+    struct sigaction newAct;
+
+    newAct.sa_handler = handler;
+    sigemptyset(&newAct.sa_mask);
+    newAct.sa_flags |= SA_RESTART;
+    if (sigaction(signum, &newAct, oldAct) == 0)
+    {
+        m_originalSigHandlers[signum] = oldAct;
+    } else {
+        throw std::runtime_error("Daemon: Failed to set signal handler");
+    }
+}
+
+void Daemon::restoreUnixSignalHandlers()
+{
+    for (SigHandlerMap::iterator it = m_originalSigHandlers.begin(); it != m_originalSigHandlers.end(); it++ )
+    {
+        sigaction(it->first, it->second, NULL);
+    }
+
+    m_originalSigHandlers.clear();
+}
+
+
 Daemon::~Daemon()
 {
     delete m_socketManager;

src/launcherlib/daemon.h

@@ -97,6 +97,16 @@ public:
      */
     int sigPipeFd() const;
 
+    /*!
+     * Set unix signal handler and save its original value.
+     */
+    void setUnixSignalHandler(int signum, sighandler_t handler);
+
+    /*!
+     * Restore unix signal handlers to their saved values.
+     */
+    void restoreUnixSignalHandlers();
+
 private:
 
     //! Disable copy-constructor
@@ -221,6 +231,10 @@ private:
     //! Single instance plugin handle
     SingleInstance * m_singleInstance;
 
+    //! Original unix signal handlers are saved here
+    typedef map<int, struct sigaction*> SigHandlerMap;
+    SigHandlerMap m_originalSigHandlers;
+
 #ifdef UNIT_TEST
     friend class Ut_Daemon;
 #endif

src/launcherlib/main.cpp

@@ -93,12 +93,13 @@ DECL_EXPORT int main(int argc, char * argv[])
         // Get fd for signal pipe.
         g_sigPipeFd = myDaemon.sigPipeFd();
 
-        // Install signal handlers
-        signal(SIGCHLD, sigChldHandler); // reap zombies
-        signal(SIGTERM, sigTermHandler); // exit launcher
-        signal(SIGUSR1, sigUsr1Handler); // enter normal mode from boot mode
-        signal(SIGUSR2, sigUsr2Handler); // enter boot mode (same as --boot-mode)
-        signal(SIGPIPE, sigPipeHandler); // broken invoker's pipe
+        // Install signal handlers. The original handlers are saved
+        // in the daemon instance so that they can be restored in boosters.
+        myDaemon.setUnixSignalHandler(SIGCHLD, sigChldHandler); // reap zombies
+        myDaemon.setUnixSignalHandler(SIGTERM, sigTermHandler); // exit launcher
+        myDaemon.setUnixSignalHandler(SIGUSR1, sigUsr1Handler); // enter normal mode from boot mode
+        myDaemon.setUnixSignalHandler(SIGUSR2, sigUsr2Handler); // enter boot mode (same as --boot-mode)
+        myDaemon.setUnixSignalHandler(SIGPIPE, sigPipeHandler); // broken invoker's pipe
 
         // Run the main loop
         myDaemon.run();