Date: Fri, 29 Jul 2016 15:11:25 +0200 From: Adam Starak <starak.adam@gmail.com> To: freebsd-hackers@freebsd.org Subject: Modify user space from kernel. Message-ID: <CAAz%2B7vqLgd5GSBfFMdD-xsAsEoujgPh8ZdKY4xZ1LO0h30OmSQ@mail.gmail.com>
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Hello! My name is Adam. I participate in Google Summer of Code this year. I came up with a big problem, which doesn't allow me to go further in my project. I made a new syscall, which is going to retrieve sysctl data and put it inside the nvlist. And here my problem is. I need to move somehow this data (packed nvlist) into the user space. Is there any chance to pass data from kernel to user space without knowing the size of it? Right now, the implementation of __sysctl() function requests void pointer and size in order to get data. If allocated memory is too low, it returns ENOMEM and you need to realloc the data. I wanted to avoid this situation. Best regards, Adam Starak
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