how to redirect from stdin to dev driver

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I am writing a device driver and have implemented file_operations write method. I would also like to be able to just redirect to the device driver, e.g.:



echo "this text is sent to driver" > /dev/driver_name


I originally assumed this would magically work with the user space message being sent to the .write and the other parameters set accordingly. LDD3 chapter 3 has some code which is pretty similar to mine, and the authors refer to testing/playing around both by invoking the write method directly and by redirecting to the driver (as I desire to do), making me think that I am on the right track. However, when I tried redirecting to the driver, I received a "Permission denied" error and it did nothing.



Any direction/links/suggestions would be greatly appreciated.




kernel drivers kernel-modules devices




share|improve this question






















  • Do you have permissions to write to the device file?
    – Ignacio Vazquez-Abrams
    Apr 3 at 1:23










  • I sudo'd the above echo line. the permissions are crw------- with root as owner.
    – Jebus
    Apr 3 at 1:56










  • You ran the echo with superuser privileges, not the shell.
    – Ignacio Vazquez-Abrams
    Apr 3 at 1:57










  • ty. How to make a driver install with different permissions?
    – Jebus
    Apr 3 at 2:08














up vote
0
down vote

favorite












I am writing a device driver and have implemented file_operations write method. I would also like to be able to just redirect to the device driver, e.g.:



echo "this text is sent to driver" > /dev/driver_name


I originally assumed this would magically work with the user space message being sent to the .write and the other parameters set accordingly. LDD3 chapter 3 has some code which is pretty similar to mine, and the authors refer to testing/playing around both by invoking the write method directly and by redirecting to the driver (as I desire to do), making me think that I am on the right track. However, when I tried redirecting to the driver, I received a "Permission denied" error and it did nothing.



Any direction/links/suggestions would be greatly appreciated.




kernel drivers kernel-modules devices




share|improve this question






















  • Do you have permissions to write to the device file?
    – Ignacio Vazquez-Abrams
    Apr 3 at 1:23










  • I sudo'd the above echo line. the permissions are crw------- with root as owner.
    – Jebus
    Apr 3 at 1:56










  • You ran the echo with superuser privileges, not the shell.
    – Ignacio Vazquez-Abrams
    Apr 3 at 1:57










  • ty. How to make a driver install with different permissions?
    – Jebus
    Apr 3 at 2:08












up vote
0
down vote

favorite









up vote
0
down vote

favorite











I am writing a device driver and have implemented file_operations write method. I would also like to be able to just redirect to the device driver, e.g.:



echo "this text is sent to driver" > /dev/driver_name


I originally assumed this would magically work with the user space message being sent to the .write and the other parameters set accordingly. LDD3 chapter 3 has some code which is pretty similar to mine, and the authors refer to testing/playing around both by invoking the write method directly and by redirecting to the driver (as I desire to do), making me think that I am on the right track. However, when I tried redirecting to the driver, I received a "Permission denied" error and it did nothing.



Any direction/links/suggestions would be greatly appreciated.




kernel drivers kernel-modules devices




share|improve this question














I am writing a device driver and have implemented file_operations write method. I would also like to be able to just redirect to the device driver, e.g.:



echo "this text is sent to driver" > /dev/driver_name


I originally assumed this would magically work with the user space message being sent to the .write and the other parameters set accordingly. LDD3 chapter 3 has some code which is pretty similar to mine, and the authors refer to testing/playing around both by invoking the write method directly and by redirecting to the driver (as I desire to do), making me think that I am on the right track. However, when I tried redirecting to the driver, I received a "Permission denied" error and it did nothing.



Any direction/links/suggestions would be greatly appreciated.





kernel drivers kernel-modules devices





share|improve this question













share|improve this question




share|improve this question








edited Apr 3 at 0:59

























asked Apr 3 at 0:47









Jebus

114




114











  • Do you have permissions to write to the device file?
    – Ignacio Vazquez-Abrams
    Apr 3 at 1:23










  • I sudo'd the above echo line. the permissions are crw------- with root as owner.
    – Jebus
    Apr 3 at 1:56










  • You ran the echo with superuser privileges, not the shell.
    – Ignacio Vazquez-Abrams
    Apr 3 at 1:57










  • ty. How to make a driver install with different permissions?
    – Jebus
    Apr 3 at 2:08
















  • Do you have permissions to write to the device file?
    – Ignacio Vazquez-Abrams
    Apr 3 at 1:23










  • I sudo'd the above echo line. the permissions are crw------- with root as owner.
    – Jebus
    Apr 3 at 1:56










  • You ran the echo with superuser privileges, not the shell.
    – Ignacio Vazquez-Abrams
    Apr 3 at 1:57










  • ty. How to make a driver install with different permissions?
    – Jebus
    Apr 3 at 2:08















Do you have permissions to write to the device file?
– Ignacio Vazquez-Abrams
Apr 3 at 1:23




Do you have permissions to write to the device file?
– Ignacio Vazquez-Abrams
Apr 3 at 1:23












I sudo'd the above echo line. the permissions are crw------- with root as owner.
– Jebus
Apr 3 at 1:56




I sudo'd the above echo line. the permissions are crw------- with root as owner.
– Jebus
Apr 3 at 1:56












You ran the echo with superuser privileges, not the shell.
– Ignacio Vazquez-Abrams
Apr 3 at 1:57




You ran the echo with superuser privileges, not the shell.
– Ignacio Vazquez-Abrams
Apr 3 at 1:57












ty. How to make a driver install with different permissions?
– Jebus
Apr 3 at 2:08




ty. How to make a driver install with different permissions?
– Jebus
Apr 3 at 2:08















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