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Date: Mon, 21 Jan 2008 09:21:32 +0100 From: Joe <zentrale.at.work@...il.com> To: Rafael Sisto <rafael.sisto@...il.com> CC: Linux kernel <linux-kernel@...r.kernel.org> Subject: Re: create a file in kernel mode. help please! Hi Rafael. Probably you haven't got any answers yet because you should NEVER EVER (i repeat: NEVER EVER, not even in college projects) go for file I/O in the kernel. You might want to think the whole thing over one or two times, i think. If it comes to you that it is absolutely necessary (i repeat again: ABSOLUTELY NECESSARY, like a solution to feed the world) then you might google for some ancient FAQ of Greg (K-H) (i think he was) where he tries to give a little more details about this kind of problem, and also gives a possible solution, IIRC. Sorry that i don't remember the exact page/adress anymore, for i intend never to look at it again. Greetz Joe Rafael Sisto schrieb: > Hi there, > obviously this is a newbie question, but I couldn't find any > documentation on how to do it.. I tried several ways but couldnt do > it. > I designed a system call, so a user will call it, and a new file will > be created ('/tmp/filexx'). After that, I have another system call, > that will map the file into the maps of the user process. The idea is > the same as IPC... > > I managed to create the file with this function (in the first system call): > fd = filp_open(path, O_CREAT | O_RDWR , 777); > > After that, the user will call another system call, and it will map > this file to the process maps. > something like this: > filp_open(route, O_RDWR,0 ); > do_mmap(fp, 0, tamano, PROT_READ | PROT_WRITE | PROT_EXEC, > MAP_SHARED, 0); > > After I call the second system call, the user tries to access the > memory, but gets the message "Bus Error". > I tried to manually create a file with vi, and then use the second > system call, and worked perfectly. I could use the shared memory > without problems. > > The problems seems to be in the first system call (with filp_open), > when I try to create a new file... Can somebody suggest me something, > on how I could fix this issue?? It is very important because it is for > a college projects. > > Greetings, and thanks in advance for the answers. > Rafael Sisto - Uruguay.- > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@...r.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > -- Sepp "ZaP" Holzmayr please reply to: zentrale.at.work@...il.com watch out for: www.rocksociety.de -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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