[PATCH] remove_file: don't call rmdir if remove_file return failure

[Denys Vlasenko]

Applied, thanks!
On Tue, Sep 4, 2018 at 9:11 AM Yu Chen <yu.chen3 at zte.com.cn> wrote:
>
> From: Chen Yu <yu.chen3 at zte.com.cn>
>
> When deleting a directory, the directory should not be removed if the
> file in the subdirectory fails to be deleted.
>
> Background information:
>
> When I tested the kernel using LTP (linux-test-project).I found the
> mv command have some issue. The LTP test case use the mv command to
> move the directory t1 in the cgroup file system to the /tmp directory.
> becase files in the cgroup file system are not allowed to be removed.
> so the mv reported "Permission denied", but I used the ls command to
> view the results and found that the directory t1 had been removed
> from the cgroup file system. For the same test case, I used the mv
> tool in the GNU coreutils, and the directory t1 will not be removed.
>
> the following testcase use busybox mv:
>
> / # mount -t cgroup -o cpu cgroup /cpu
> / # cd /cpu
> /cpu # mkdir -p t1
> /cpu # ls
> cgroup.clone_children  cpu.cfs_period_us  cpu.stat  t1
> cgroup.procs           cpu.cfs_quota_us   notify_on_release  tasks
> cgroup.sane_behavior   cpu.shares         release_agent
> /cpu # mv t1 /tmp
> mv: can't remove 't1/cgroup.procs': Operation not permitted
> mv: can't remove 't1/cpu.cfs_period_us': Operation not permitted
> mv: can't remove 't1/cpu.stat': Operation not permitted
> mv: can't remove 't1/cpu.shares': Operation not permitted
> mv: can't remove 't1/cpu.cfs_quota_us': Operation not permitted
> mv: can't remove 't1/tasks': Operation not permitted
> mv: can't remove 't1/notify_on_release': Operation not permitted
> mv: can't remove 't1/cgroup.clone_children': Operation not permitted
> /cpu # ls
> cgroup.clone_children  cpu.cfs_period_us  cpu.stat  cgroup.procs
> cpu.cfs_quota_us       notify_on_release  tasks   cgroup.sane_behavior
> cpu.shares             release_agent
> /cpu #
>
> This patch fixed it, don't call rmdir if remove_file return failure,
> and under certain file systems, the mv could work normally.
>
> Signed-off-by: Chen Yu <yu.chen3 at zte.com.cn>
> ---
>  libbb/remove_file.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/libbb/remove_file.c b/libbb/remove_file.c
> index 86c9a5c..a5c1da7 100644
> --- a/libbb/remove_file.c
> +++ b/libbb/remove_file.c
> @@ -73,7 +73,7 @@ int FAST_FUNC remove_file(const char *path, int flags)
>                                 return status;
>                 }
>
> -               if (rmdir(path) < 0) {
> +               if (!status && rmdir(path) < 0) {
>                         bb_perror_msg("can't remove '%s'", path);
>                         return -1;
>                 }
> --
> 1.8.3.1
>