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

From: Blaisorblade
Date: Tue Jan 23 2007 - 03:03:44 EST


On Monday 22 January 2007 21:13, Johannes Stezenbach wrote:
> Hi,
>
> 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.
>
> Johannes

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.

> 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 2007-01-22 20:53:23.000000000 +0100 @@
> -76,7 +76,17 @@ 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);
> +
> +/* gnu_dev_makedev from glibc's sys/sysmacros.h */
> +static inline unsigned long long makedev(unsigned int major, unsigned int
> minor) +{
> + return ((minor & 0xff) | ((major & 0xfff) << 8)
> + | (((unsigned long long int) (minor & ~0xff)) << 12)
> + | (((unsigned long long int) (major & ~0xfff)) << 32));
> +
> +}
> +
> +extern int do_mknod(const char *file, int mode, unsigned long long dev);
> 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 2007-01-22
> 20:57:58.000000000 +0100 @@ -740,6 +740,7 @@ int hostfs_mknod(struct inode
> *dir, stru
> struct inode *inode;
> char *name;
> int err = -ENOMEM;
> + unsigned long long udev;
>
> inode = iget(dir->i_sb, 0);
> if(inode == NULL)
> @@ -755,7 +756,9 @@ int hostfs_mknod(struct inode *dir, stru
> goto out_put;
>
> init_special_inode(inode, mode, dev);
> - err = do_mknod(name, mode, dev);
> + /* userspace has different dev_t encoding than kernel... */
> + udev = makedev(MAJOR(dev), MINOR(dev));
> + err = do_mknod(name, mode, udev);
> 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 2007-01-22
> 20:54:37.000000000 +0100 @@ -295,7 +295,7 @@ 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 long long dev)
> {
> int err;
>
>
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--
Inform me of my mistakes, so I can add them to my list!
Paolo Giarrusso, aka Blaisorblade
http://www.user-mode-linux.org/~blaisorblade
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