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Serial Port configuration in RHEL

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  • K Offline
    K Offline
    kuzulis
    Qt Champions 2020
    wrote on last edited by
    #15

    QIODevice::OpenMode mode = QIODevice::ReadOnly | QIODevice::Unbuffered;

    Did you read documentation? QIODevice::Unbuffered it is unsupported mode.

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    • K kuzulis

      QIODevice::OpenMode mode = QIODevice::ReadOnly | QIODevice::Unbuffered;

      Did you read documentation? QIODevice::Unbuffered it is unsupported mode.

      N Offline
      N Offline
      Nimika
      wrote on last edited by
      #16

      @kuzulis Yeah I made it as comment.

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      • N Nimika

        Thankyou both of you.
        Please tell me how to add my normal user to the dialout group?
        What is dialout group?

        mrjjM Offline
        mrjjM Offline
        mrjj
        Lifetime Qt Champion
        wrote on last edited by mrjj
        #17

        @Nimika

        • Please tell me how to add my normal user to the dialout group?
          sudo usermod -a -G dialout theuser

        • What is dialout group?
          Its a predefined group found in many distros.
          From old times it was used to allowed modems
          to make connection etc. ( ie allow the user to connect to the internet :)

        So often the system has this group and any user in it, have access to /dev/ttySX

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        • N Nimika

          Thankyou both of you.
          Please tell me how to add my normal user to the dialout group?
          What is dialout group?

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

          @Nimika You really should learn how user/groups and access rights management is working on UNIX/Linux.

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

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          • N Offline
            N Offline
            Nimika
            wrote on last edited by
            #19

            @jsulm Actually my system is Red Hat Enterprise Linux based so it is different to use its commands.

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            • mrjjM mrjj

              @Nimika

              • Please tell me how to add my normal user to the dialout group?
                sudo usermod -a -G dialout theuser

              • What is dialout group?
                Its a predefined group found in many distros.
                From old times it was used to allowed modems
                to make connection etc. ( ie allow the user to connect to the internet :)

              So often the system has this group and any user in it, have access to /dev/ttySX

              N Offline
              N Offline
              Nimika
              wrote on last edited by
              #20

              @mrjj Thank you !! let me add it now and search whether it will work or not.....

              mrjjM 1 Reply Last reply
              0
              • N Nimika

                @mrjj Thank you !! let me add it now and search whether it will work or not.....

                mrjjM Offline
                mrjjM Offline
                mrjj
                Lifetime Qt Champion
                wrote on last edited by mrjj
                #21

                @Nimika
                Np. as far as I can see it's the same for Red Hat with ttySX access, so there is
                tons on google on the topic on allowing user X to read and write to /dev/ttSxxx
                stuff.
                http://ithelpblog.com/os/linux/bashandscripts/howto-add-user-to-group-on-linux-redhat-rhel-centos-fedora/

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                • SGaistS SGaist

                  NEVER EVER use root like that. All the more when developing. It's bad practice and doing so you're opening a gaping security hole.

                  Add your normal user to the dialout group and be done with it.

                  N Offline
                  N Offline
                  Nimika
                  wrote on last edited by
                  #22

                  @SGaist Can I use serial ports to any user other than root?

                  mrjjM 1 Reply Last reply
                  0
                  • N Nimika

                    @SGaist Can I use serial ports to any user other than root?

                    mrjjM Offline
                    mrjjM Offline
                    mrjj
                    Lifetime Qt Champion
                    wrote on last edited by mrjj
                    #23

                    @Nimika
                    Hi
                    Any user can be granted access to /dev/X devices.
                    Often it is done via the dialout group as its already assigned to serial devices such as ttyS0 and
                    any user that is member of that group can use it.
                    so often
                    sudo adduser TheUserName dialout
                    and and reboot is all that is needed.
                    Adding user to group might have slightly different syntax on RH but concept and rights are 100% the same.:)
                    http://websistent.com/fix-serial-port-permission-denied-errors-linux/

                    N jsulmJ 2 Replies Last reply
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                    • mrjjM mrjj

                      @Nimika
                      Hi
                      Any user can be granted access to /dev/X devices.
                      Often it is done via the dialout group as its already assigned to serial devices such as ttyS0 and
                      any user that is member of that group can use it.
                      so often
                      sudo adduser TheUserName dialout
                      and and reboot is all that is needed.
                      Adding user to group might have slightly different syntax on RH but concept and rights are 100% the same.:)
                      http://websistent.com/fix-serial-port-permission-denied-errors-linux/

                      N Offline
                      N Offline
                      Nimika
                      wrote on last edited by
                      #24

                      @mrjj Thanks let me try it.

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                      • mrjjM mrjj

                        @Nimika
                        Hi
                        Any user can be granted access to /dev/X devices.
                        Often it is done via the dialout group as its already assigned to serial devices such as ttyS0 and
                        any user that is member of that group can use it.
                        so often
                        sudo adduser TheUserName dialout
                        and and reboot is all that is needed.
                        Adding user to group might have slightly different syntax on RH but concept and rights are 100% the same.:)
                        http://websistent.com/fix-serial-port-permission-denied-errors-linux/

                        jsulmJ Offline
                        jsulmJ Offline
                        jsulm
                        Lifetime Qt Champion
                        wrote on last edited by
                        #25

                        @mrjj @Nimika Just a note: after adding currently logged on user to a group you do not have to reboot (its not Windows :-)) - just log out and log in again.

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

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                        • jsulmJ jsulm

                          @mrjj @Nimika Just a note: after adding currently logged on user to a group you do not have to reboot (its not Windows :-)) - just log out and log in again.

                          N Offline
                          N Offline
                          Nimika
                          wrote on last edited by
                          #26

                          @jsulm Thank you!!
                          But still in my case maybe RHEL is not allowing any other user to add in dialout group.

                          mrjjM jsulmJ 2 Replies Last reply
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                          • N Nimika

                            @jsulm Thank you!!
                            But still in my case maybe RHEL is not allowing any other user to add in dialout group.

                            mrjjM Offline
                            mrjjM Offline
                            mrjj
                            Lifetime Qt Champion
                            wrote on last edited by
                            #27

                            @Nimika said in Serial Port configuration in RHEL:

                            RHEL is not allowing any other user to add in dialout group.

                            cant you just use sudo in front?

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                            • N Nimika

                              @jsulm Thank you!!
                              But still in my case maybe RHEL is not allowing any other user to add in dialout group.

                              jsulmJ Offline
                              jsulmJ Offline
                              jsulm
                              Lifetime Qt Champion
                              wrote on last edited by
                              #28

                              @Nimika RHEL works like any other Linux distribution. To add a user to a group you need to be root. You can either login as root, or just enter su in a terminal window enter your root password and then add the user to the group. su is used to become root in a shell (you need root password).
                              @mrjj I think on RHEL sudo is usually not used, so sudo will probably not work (as far as I know, I could be wrong as I use Ubuntu).

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

                              N mrjjM 2 Replies Last reply
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                              • jsulmJ jsulm

                                @Nimika RHEL works like any other Linux distribution. To add a user to a group you need to be root. You can either login as root, or just enter su in a terminal window enter your root password and then add the user to the group. su is used to become root in a shell (you need root password).
                                @mrjj I think on RHEL sudo is usually not used, so sudo will probably not work (as far as I know, I could be wrong as I use Ubuntu).

                                N Offline
                                N Offline
                                Nimika
                                wrote on last edited by
                                #29

                                @jsulm
                                Yeah I did all possibilities which I think can be done on RHEL.
                                By the way Thanks a lot for your all kind replies. :)

                                jsulmJ 1 Reply Last reply
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                                • N Nimika

                                  @jsulm
                                  Yeah I did all possibilities which I think can be done on RHEL.
                                  By the way Thanks a lot for your all kind replies. :)

                                  jsulmJ Offline
                                  jsulmJ Offline
                                  jsulm
                                  Lifetime Qt Champion
                                  wrote on last edited by
                                  #30

                                  @Nimika So, is your user now member of dialout group? You can check this executing "groups" command in a terminal (not as root but as the user who needs the access rights!). You can add a user to a group manually: open /etc/group file in an editor (as root), look for a line like "dialout:x:115:" and append user name at the end of that line.

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

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                                  • SGaistS Offline
                                    SGaistS Offline
                                    SGaist
                                    Lifetime Qt Champion
                                    wrote on last edited by
                                    #31

                                    In addition to what my fellows already wrote, if you're not too found of manipulating your user setting with the command line, most of desktop environment (KDE, Gnome, etc.) provide user management software so you'll likely be able to add your user to the dialout group with them. They should ask for an admin password when required.

                                    Interested in AI ? www.idiap.ch
                                    Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                                    1 Reply Last reply
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                                    • jsulmJ jsulm

                                      @Nimika RHEL works like any other Linux distribution. To add a user to a group you need to be root. You can either login as root, or just enter su in a terminal window enter your root password and then add the user to the group. su is used to become root in a shell (you need root password).
                                      @mrjj I think on RHEL sudo is usually not used, so sudo will probably not work (as far as I know, I could be wrong as I use Ubuntu).

                                      mrjjM Offline
                                      mrjjM Offline
                                      mrjj
                                      Lifetime Qt Champion
                                      wrote on last edited by
                                      #32

                                      @jsulm
                                      Oh, you are right. it might not be set up at all
                                      https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_OpenStack_Platform/2/html/Getting_Started_Guide/ch02s03.html
                                      so su is the way to go.

                                      1 Reply Last reply
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                                      • jsulmJ jsulm

                                        @Nimika So, is your user now member of dialout group? You can check this executing "groups" command in a terminal (not as root but as the user who needs the access rights!). You can add a user to a group manually: open /etc/group file in an editor (as root), look for a line like "dialout:x:115:" and append user name at the end of that line.

                                        N Offline
                                        N Offline
                                        Nimika
                                        wrote on last edited by
                                        #33

                                        @jsulm
                                        No my user is not the member because its not working in the dialout group.
                                        I did by editing to the group file as well. Whenever I am in my root and adding the user to the group it is showing that this user is already have the group.

                                        @SGaist
                                        which management software you are talking about??

                                        mrjjM jsulmJ 2 Replies Last reply
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                                        • N Nimika

                                          @jsulm
                                          No my user is not the member because its not working in the dialout group.
                                          I did by editing to the group file as well. Whenever I am in my root and adding the user to the group it is showing that this user is already have the group.

                                          @SGaist
                                          which management software you are talking about??

                                          mrjjM Offline
                                          mrjjM Offline
                                          mrjj
                                          Lifetime Qt Champion
                                          wrote on last edited by
                                          #34

                                          @Nimika
                                          HI
                                          I think the champion means that many newer distros have also a GUI version
                                          to change user / groups versus using the command line. :)

                                          N 1 Reply Last reply
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