Re: [patch] replacing "/dev/root" in /proc/mounts

Erik Andersen (andersen@xmission.com)
Fri, 8 Oct 1999 08:30:00 -0600

On Fri Oct 08, 1999 at 09:44:05AM +0200, Andreas Schwab wrote:
> Erik Andersen <andersen@xmission.com> writes:
>
> |> #include <stdio.h>
> |> #include <sys/stat.h>
> |> #include <unistd.h>
> |> int main(int argc, char **argv)
> |> {
> |> struct stat statBuf;
> |> unsigned int major, minor;
> |> stat("/", &statBuf);
> |> major=minor=statBuf.st_dev;
> |> printf("/ is on device major %d, minor %d\n",
> |> major>>8, minor&0xff);
>
> This is bad, you should be using the major and minor macros.

Right.

I was guessing how Wakko might have written a stat based app, and then I
go on to say this violates the interface by peeking under the kernel's
skirt. I had already checked, and the MAJOR and MINOR macros in kdev_t.h
are wrapped up an inside #ifdef __KERNEL__, and so are not available to
user space. User space simply has no way of knowing what a dev_t might
be.

-Erik

--
Erik B. Andersen   Web:    http://www.xmission.com/~andersen/ 
                   email:  andersee@debian.org
--This message was written using 73% post-consumer electrons--


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