Re: [uml-devel] [PATCH] [UML] fix mknod

From: Johannes Stezenbach
Date: Tue Jan 23 2007 - 08:18:12 EST


On Tue, Jan 23, 2007 at 09:02:30AM +0100, Blaisorblade wrote:
> On Monday 22 January 2007 21:13, Johannes Stezenbach wrote:
> >
> > I was playing with user-mode Linux and found that mknod creates
> > devices node in hostfs with wrong major/minor numbers.
> > The patch below fixes it for me.
>
> Hmpf. Still having this bug on hostfs is quite bad. Thanks for reporting.
>
> It should be hostfs_user.c to take major and minor and to combine them
> correctly - it can use libc's macros.

Right, below is a better patch.


Thanks,
Johannes

---
Fix UML hostfs mknod(): userspace has differernt
dev_t size and encoding than kernel, so extract major/minor
and reencode using glibc makedev() macro.

Signed-off-by: Johannes Stezenbach <js@xxxxxxxxxxx>

diff -rup linux-2.6.19.orig/fs/hostfs/hostfs.h linux-2.6.19/fs/hostfs/hostfs.h
--- linux-2.6.19.orig/fs/hostfs/hostfs.h 2006-11-29 22:57:37.000000000 +0100
+++ linux-2.6.19/fs/hostfs/hostfs.h 2007-01-23 14:11:03.000000000 +0100
@@ -76,7 +76,7 @@ extern int make_symlink(const char *from
extern int unlink_file(const char *file);
extern int do_mkdir(const char *file, int mode);
extern int do_rmdir(const char *file);
-extern int do_mknod(const char *file, int mode, int dev);
+extern int do_mknod(const char *file, int mode, unsigned int major, unsigned int minor);
extern int link_file(const char *from, const char *to);
extern int do_readlink(char *file, char *buf, int size);
extern int rename_file(char *from, char *to);
diff -rup linux-2.6.19.orig/fs/hostfs/hostfs_kern.c linux-2.6.19/fs/hostfs/hostfs_kern.c
--- linux-2.6.19.orig/fs/hostfs/hostfs_kern.c 2006-11-29 22:57:37.000000000 +0100
+++ linux-2.6.19/fs/hostfs/hostfs_kern.c 2007-01-23 14:11:20.000000000 +0100
@@ -755,7 +755,7 @@ int hostfs_mknod(struct inode *dir, stru
goto out_put;

init_special_inode(inode, mode, dev);
- err = do_mknod(name, mode, dev);
+ err = do_mknod(name, mode, MAJOR(dev), MINOR(dev));
if(err)
goto out_free;

diff -rup linux-2.6.19.orig/fs/hostfs/hostfs_user.c linux-2.6.19/fs/hostfs/hostfs_user.c
--- linux-2.6.19.orig/fs/hostfs/hostfs_user.c 2006-11-29 22:57:37.000000000 +0100
+++ linux-2.6.19/fs/hostfs/hostfs_user.c 2007-01-23 14:11:39.000000000 +0100
@@ -295,11 +295,11 @@ int do_rmdir(const char *file)
return(0);
}

-int do_mknod(const char *file, int mode, int dev)
+int do_mknod(const char *file, int mode, unsigned int major, unsigned int minor)
{
int err;

- err = mknod(file, mode, dev);
+ err = mknod(file, mode, makedev(major, minor));
if(err) return(-errno);
return(0);
}
-
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