Re: [PATCH] AOSP: erofs-utils: fix sub directory prefix path in canned fs_config

[Yue Hu <zbestahu@gmail.com>]

On Tue, 22 Dec 2020 15:04:58 +0800
Gao Xiang <hsiangkao@redhat.com> wrote:

> Hi Yue,
> 
> On Tue, Dec 22, 2020 at 02:31:12PM +0800, Gao Xiang wrote:
> 
> ...
> 
> > 
> > Ok, I will try to find some clue to verify later.
> >   
> > >   
> > > >   
> > > > > Moreover, we should not add the mount point to fspath on root inode for
> > > > > fs_config() branch.    
> > > > 
> > > > Is there some descriptive words or reference for this? To be honest,
> > > > I'm quite unsure about this kind of Android-specific things... :(  
> > > 
> > > Refer to change: mksquashfs: Run android_fs_config() on the root inode
> > > 
> > > I think erofs of AOSP has this issue also. Am i right?  
> > 
> > Not quite sure if it effects non-canned fs_config after
> > reading the commit message...
> > https://android.googlesource.com/platform/external/squashfs-tools/+/85a6bc1e52bb911f195c5dc0890717913938c2d1%5E%21/#F0
> > 
> > And no permission to access Bug 72745016, so...
> > maybe we need to limit this to non-canned fs_config only?
> > (at least confirming the original case would be better)
> > 
> > BTW, Also, from its testcase command line in the commit message:
> > "mksquashfs path system.raw.img -fs-config-file fs_config -android-fs-config"
> > 
> > I'm not sure if "--mount-point" is passed in so I think for
> > such case no need to use such "goto" as well? 
> > 
> > Thanks,
> > Gao Xiang  
> 
> Could you verify the following patch if possible? (without compilation,
> I don't have test environment now since AOSP code is on my PC)
> 
> From: Yue Hu <huyue2@yulong.com>
> Date: Tue, 22 Dec 2020 14:52:22 +0800
> Subject: [PATCH] AOSP: erofs-utils: fix sub-directory prefix for canned
>  fs_config
> 
> "failed to find [%s] in canned fs_config" is observed by using
> "--fs-config-file" option under Android 10.
> 
> Notice that canned fs_config has a prefix to sub-directory if
> "--mount-point" presents. However, such prefix cannot be added by
> just using erofs_fspath().
> 
> Fixes: 8a9e8046f170 ("AOSP: erofs-utils: add fs_config support")
> Signed-off-by: Yue Hu <huyue2@yulong.com>
> Signed-off-by: Gao Xiang <hsiangkao@aol.com>
> ---
>  lib/inode.c | 18 +++++++++++-------
>  1 file changed, 11 insertions(+), 7 deletions(-)
> 
> diff --git a/lib/inode.c b/lib/inode.c
> index 3d634fc..9469074 100644
> --- a/lib/inode.c
> +++ b/lib/inode.c
> @@ -701,21 +701,25 @@ int erofs_droid_inode_fsconfig(struct erofs_inode *inode,
>  	char *fspath;
>  
>  	inode->capabilities = 0;
> +	if (!cfg.mount_point)
> +		fspath = erofs_fspath(path);

lib/inode.c:688:10: error: assigning to 'char *' from 'const char *' discards...
                fspath = erofs_fspath(path);
                       ^ ~~~~~~~~~~~~~~~~~~

-           fspath = erofs_fspath(path);
+         fspath = (char *)erofs_fspath(path);


> +	else if (asprintf(&fspath, "%s/%s", cfg.mount_point,
> +			  erofs_fspath(path)) <= 0)

The argument of path will be root directory. And canned fs_config for root directory as
below:

0 0 755 selabel=u:object_r:rootfs:s0 capabilities=0x0

So, cannot add mount point to root directory for canned fs_config. And what about non-canned
fs_config?

Thx.


> +		return -ENOMEM;
> +
> +
>  	if (cfg.fs_config_file)
> -		canned_fs_config(erofs_fspath(path),
> +		canned_fs_config(fspath,
>  				 S_ISDIR(st->st_mode),
>  				 cfg.target_out_path,
>  				 &uid, &gid, &mode, &inode->capabilities);
> -	else if (cfg.mount_point) {
> -		if (asprintf(&fspath, "%s/%s", cfg.mount_point,
> -			     erofs_fspath(path)) <= 0)
> -			return -ENOMEM;
> -
> +	else
>  		fs_config(fspath, S_ISDIR(st->st_mode),
>  			  cfg.target_out_path,
>  			  &uid, &gid, &mode, &inode->capabilities);
> +
> +	if (cfg.mount_point)
>  		free(fspath);
> -	}
>  	st->st_uid = uid;
>  	st->st_gid = gid;
>  	st->st_mode = mode | stat_file_type_mask;