Date: Fri, 17 Jun 2005 16:17:57 +0200 From: Hannes Mayer <debiandude@gmail.com> To: freebsd-stable@freebsd.org, Daniel O'Connor <doconnor@gsoft.com.au> Subject: Re: Kernel module/IPC with userland: create and write to FIFO Message-ID: <bedc2e380506170717b6acef6@mail.gmail.com> In-Reply-To: <200506172159.34920.doconnor@gsoft.com.au> References: <bedc2e38050617050624a7ff2e@mail.gmail.com> <200506172159.34920.doconnor@gsoft.com.au>
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G'Day Daniel! On 6/17/05, Daniel O'Connor <doconnor@gsoft.com.au> wrote: > On Fri, 17 Jun 2005 21:36, Hannes Mayer wrote: > > To cut a long story short, how can I open a FIFO in kernel space and > > write to it, so I can open and read from it in userspace ? >=20 > Why don't you create a device node? >=20 > If you read and write to it, it acts like a FIFO. Thanks for your reply! :-) Well, the reason why I want to use a true FIFO is, that data is sampled i.e. every second and I want to write it to disk in userspace only every minute or so. So if I add a ".d_ioctl" to "struct cdevsw" for the device node, I have to make a function in the kernel module for handling the userspace read request and I have to cache the sampled data in the kernel module. I want the module to be flexible, so if I don't sample at a fixed frequency (i.e. event counting) I don't know how much data is coming in in a certain time interval and with a FIFO I don't have to care about the data-cache size. Thanks again & best regards, Hannes.
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