Messages in this thread | | | Date | Mon, 21 Jan 2008 09:44:07 -0300 | From | "Rafael Sisto" <> | Subject | Re: create a file in kernel mode. help please! |
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Thanks Joe for the answer! I will find another work around for my problem, then!
greetings, Rafael Sisto.
On Jan 21, 2008 5:21 AM, Joe <zentrale.at.work@gmail.com> wrote: > 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@vger.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@gmail.com > > watch out for: > www.rocksociety.de >
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