Re: [PATCH 04/14] btrfs-progs: don't leak fd in get_fs_info

[Eric Sandeen <sandeen@redhat.com>]

On 3/4/13 4:39 PM, Eric Sandeen wrote:
> If we discover that a passed-in fd is not a mountpoint,
> we determine whether it is a device, and issue another
> open() against the device's mount point if it is mounted.
> 
> If we do so, ensure this 2nd fd gets closed before we return
> so that it does not leak, by consolidating error returns.
> 
> Signed-off-by: Eric Sandeen <sandeen@redhat.com>

Gah, self-nak on this for now, I started trying to make a
regression test for scrub, and this makes it fail.

Don't know why yet.

-Eric

> ---
>  utils.c |   21 ++++++++++++++-------
>  1 files changed, 14 insertions(+), 7 deletions(-)
> 
> diff --git a/utils.c b/utils.c
> index 1813dda..54d577c 100644
> --- a/utils.c
> +++ b/utils.c
> @@ -1462,6 +1462,7 @@ int get_fs_info(int fd, char *path, struct btrfs_ioctl_fs_info_args *fi_args,
>  		struct btrfs_ioctl_dev_info_args **di_ret)
>  {
>  	int ret = 0;
> +	int fd2 = -1;
>  	int ndevs = 0;
>  	int i = 1;
>  	struct btrfs_fs_devices *fs_devices_mnt = NULL;
> @@ -1484,19 +1485,22 @@ int get_fs_info(int fd, char *path, struct btrfs_ioctl_fs_info_args *fi_args,
>  		i = fs_devices_mnt->latest_devid;
>  		memcpy(fi_args->fsid, fs_devices_mnt->fsid, BTRFS_FSID_SIZE);
>  		close(fd);
> -		fd = open_file_or_dir(mp);
> -		if (fd < 0)
> +		fd2 = open_file_or_dir(mp);
> +		if (fd2 < 0)
>  			return -errno;
> +		fd = fd2;
>  	} else if (ret) {
>  		return -errno;
>  	}
>  
>  	if (!fi_args->num_devices)
> -		return 0;
> +		goto out;
>  
>  	di_args = *di_ret = malloc(fi_args->num_devices * sizeof(*di_args));
> -	if (!di_args)
> -		return -errno;
> +	if (!di_args) {
> +		ret = -errno;
> +		goto out;
> +	}
>  
>  	for (; i <= fi_args->max_id; ++i) {
>  		BUG_ON(ndevs >= fi_args->num_devices);
> @@ -1504,13 +1508,16 @@ int get_fs_info(int fd, char *path, struct btrfs_ioctl_fs_info_args *fi_args,
>  		if (ret == -ENODEV)
>  			continue;
>  		if (ret)
> -			return ret;
> +			goto out;
>  		ndevs++;
>  	}
>  
>  	BUG_ON(ndevs == 0);
>  
> -	return 0;
> +out:
> +	if (fd2 != -1)
> +		close(fd2);
> +	return ret;
>  }
>  
>  #define isoctal(c)	(((c) & ~7) == '0')
>