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Segmentation fault (core dumped) on my application

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  • R Renn

    @jsulm The point? I do not understand. I have found a mistake, when I delete this code yes no notification Segmentation, but formnya appears twice, the first has entered the root through pkexec, the other is there anything in the gui.
    I mean the following code:
    ui->browse->setIcon(icon);
    ui->browse->setIconSize(pix.size());

    jsulmJ Offline
    jsulmJ Offline
    jsulm
    Lifetime Qt Champion
    wrote on last edited by
    #13

    @Renn Well, I think if you don't call ui->setupUi(this) then ui->browse will probably be null and you just dereference a null pointer which leads to the segmentation fault.
    ui->setupUi(this) initializes all the stuff in ui.

    if(getuid() > 0){
    // Here you do not call ui->setupUi(this);!
    pkexec.start("pkexec " + locate);
    pkexec.waitForFinished();
    }
    else{
    ui->setupUi(this);
    }
    

    https://forum.qt.io/topic/113070/qt-code-of-conduct

    R 1 Reply Last reply
    0
    • jsulmJ jsulm

      @Renn Well, I think if you don't call ui->setupUi(this) then ui->browse will probably be null and you just dereference a null pointer which leads to the segmentation fault.
      ui->setupUi(this) initializes all the stuff in ui.

      if(getuid() > 0){
      // Here you do not call ui->setupUi(this);!
      pkexec.start("pkexec " + locate);
      pkexec.waitForFinished();
      }
      else{
      ui->setupUi(this);
      }
      
      R Offline
      R Offline
      Renn
      wrote on last edited by
      #14

      @jsulm What should I do now? If I put ui-> setupUi (this); before and after, there are still some more than one, the other one did not go through pkexec root, while the other was entering through pkexec root.

      jsulmJ 1 Reply Last reply
      0
      • Hamed.MasafiH Hamed.Masafi

        @Renn No, they are not same. The a with qApp and QApplication::instance() is equal.
        Can you please paste full source (main.cpp, ui_class.cpp and ui_class.h) ?

        R Offline
        R Offline
        Renn
        wrote on last edited by
        #15

        @Hamed.Masafi Oh not the same, this is code that really complete the form ui is just testing me so that the application can go through pkexec root. under the code themselves:
        untitled.h
        #ifndef UNTITLED_H
        #define UNTITLED_H
        #include <QMainWindow>

        namespace Ui {
        class untitled;
        }

        class untitled : public QMainWindow
        {
        Q_OBJECT

        public:
        explicit untitled(QWidget *parent = 0);
        ~untitled();

        private slots:

        private:
        Ui::untitled *ui;
        };
        #endif // UNTITLED_H

        untitled.cpp
        #include "untitled.h"
        #include "ui_untitled.h"
        #include <QProcess>
        #include <QDebug>
        #include <QFileDialog>
        extern QString locate;
        untitled::untitled(QWidget *parent) :
        QMainWindow(parent),
        ui(new Ui::untitled)
        {
        //ui->setupUi(this);
        qDebug() << getuid();
        QProcess pkexec;
        if(getuid() > 0){
        //ui->setupUi(this);
        pkexec.start("pkexec " + locate);
        pkexec.waitForFinished();
        ui->setupUi(this);
        }
        // else{
        // ui->setupUi(this);
        // }
        //Change button to Icon Image

        QPixmap pix("/home/rnd/untitled/image/image.ico");
        QIcon icon(pix);
        //ui->browse->setIcon(icon);
        //ui->browse->setIconSize(pix.size());
        

        }

        untitled::~untitled()
        {
        delete ui;
        }

        main.cpp
        #include "untitled.h"
        #include <QApplication>
        QString locate;
        int main(int argc, char *argv[])
        {
        QApplication a(argc, argv);
        locate = a.arguments().at(0);
        untitled w;
        w.show();

        return a.exec();
        

        }

        1 Reply Last reply
        0
        • Hamed.MasafiH Offline
          Hamed.MasafiH Offline
          Hamed.Masafi
          wrote on last edited by
          #16
          #include "untitled.h"
          #include "ui_untitled.h"
          #include <QProcess>
          #include <QDebug>
          #include <QFileDialog>
          extern QString locate;
          
          untitled::untitled(QWidget *parent) : QMainWindow(parent), ui(new Ui::untitled)
          {
          	qDebug() << getuid();
          	QProcess pkexec;
          	if(getuid() > 0){
          		//ui->setupUi(this);
          		pkexec.start("pkexec " + locate);
          		pkexec.waitForFinished();
          	}
          	
          	ui->setupUi(this);
          
          	//Change button to Icon Image
          	QPixmap pix("/home/rnd/untitled/image/image.ico");
          	QIcon icon(pix);
          	//ui->browse->setIcon(icon);
          	//ui->browse->setIconSize(pix.size());
          }
          

          Remote object sharing (OO RPC)
          http://forum.qt.io/topic/60680/remote-object-sharing-oo-rpc-solved

          Advanced, Powerful and easy to use ORM for Qt5
          https://forum.qt.io/topic/67417/advanced-powerful-and-easy-to-use-orm-for-qt5

          R 1 Reply Last reply
          0
          • Hamed.MasafiH Hamed.Masafi
            #include "untitled.h"
            #include "ui_untitled.h"
            #include <QProcess>
            #include <QDebug>
            #include <QFileDialog>
            extern QString locate;
            
            untitled::untitled(QWidget *parent) : QMainWindow(parent), ui(new Ui::untitled)
            {
            	qDebug() << getuid();
            	QProcess pkexec;
            	if(getuid() > 0){
            		//ui->setupUi(this);
            		pkexec.start("pkexec " + locate);
            		pkexec.waitForFinished();
            	}
            	
            	ui->setupUi(this);
            
            	//Change button to Icon Image
            	QPixmap pix("/home/rnd/untitled/image/image.ico");
            	QIcon icon(pix);
            	//ui->browse->setIcon(icon);
            	//ui->browse->setIconSize(pix.size());
            }
            
            R Offline
            R Offline
            Renn
            wrote on last edited by
            #17

            @Hamed.Masafi That's the same mas, will appear 2 form as I mentioned earlier..

            1 Reply Last reply
            0
            • R Renn

              @jsulm What should I do now? If I put ui-> setupUi (this); before and after, there are still some more than one, the other one did not go through pkexec root, while the other was entering through pkexec root.

              jsulmJ Offline
              jsulmJ Offline
              jsulm
              Lifetime Qt Champion
              wrote on last edited by
              #18

              @Renn You should explain better what you actually want to do. Why do you call ui->setupUi(this) only if getuid()>0?

              if(getuid() > 0){
              // Do you want to have an UI in this case?
              pkexec.start("pkexec " + locate);
              pkexec.waitForFinished();
              }
              else{
              ui->setupUi(this);
              }
              

              https://forum.qt.io/topic/113070/qt-code-of-conduct

              R 1 Reply Last reply
              0
              • Hamed.MasafiH Offline
                Hamed.MasafiH Offline
                Hamed.Masafi
                wrote on last edited by
                #19

                Oh, you'r right, but what is getuid() ??

                Remote object sharing (OO RPC)
                http://forum.qt.io/topic/60680/remote-object-sharing-oo-rpc-solved

                Advanced, Powerful and easy to use ORM for Qt5
                https://forum.qt.io/topic/67417/advanced-powerful-and-easy-to-use-orm-for-qt5

                jsulmJ 1 Reply Last reply
                0
                • jsulmJ jsulm

                  @Renn You should explain better what you actually want to do. Why do you call ui->setupUi(this) only if getuid()>0?

                  if(getuid() > 0){
                  // Do you want to have an UI in this case?
                  pkexec.start("pkexec " + locate);
                  pkexec.waitForFinished();
                  }
                  else{
                  ui->setupUi(this);
                  }
                  
                  R Offline
                  R Offline
                  Renn
                  wrote on last edited by
                  #20

                  @jsulm Actually I outsmart gui so that I can enter the root through the framework polkit using pkexec in QProcess. When I write code
                  ui->setupUi (this);
                  pkexec.start("pkexec" + locate);
                  pkexec.waitForFinished();
                  form it appears 2, I outsmart menggunakai if else, in part if I enter the command QProcess and else that I enter ui->setupUi(this);
                  When I was running in qt no anything, but when I run through the terminal, at that time I realized that my application that I made it crashes with a notice "Segmentation fault (core dumped)"

                  1 Reply Last reply
                  0
                  • Hamed.MasafiH Hamed.Masafi

                    Oh, you'r right, but what is getuid() ??

                    jsulmJ Offline
                    jsulmJ Offline
                    jsulm
                    Lifetime Qt Champion
                    wrote on last edited by
                    #21

                    @Hamed.Masafi Get user ID (man getuid)

                    https://forum.qt.io/topic/113070/qt-code-of-conduct

                    R 1 Reply Last reply
                    0
                    • jsulmJ jsulm

                      @Hamed.Masafi Get user ID (man getuid)

                      R Offline
                      R Offline
                      Renn
                      wrote on last edited by
                      #22

                      @jsulm Now I have to do?

                      1 Reply Last reply
                      0

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