[PATCH v5] erofs-utils: fsck: introduce exporting xattrs

[Gao Xiang]

Hi Jianan,

On 2024/9/6 10:22, Hongzhen Luo wrote:
> The current `fsck --extract` does not support exporting the extended
> attributes of files. This patch adds `--xattrs` option to dump the
> extended attributes, as well as the `--no-xattrs` option to not dump
> the extended attributes.
> 
> Signed-off-by: Hongzhen Luo <hongzhen at linux.alibaba.com>

Could you confirm this version?

Thanks,
Gao Xiang

> ---
> v5: Adjust the help information.
> v4: https://lore.kernel.org/all/20240905113723.1937634-1-hongzhen@linux.alibaba.com/
> v3: https://lore.kernel.org/all/20240903113729.3539578-1-hongzhen@linux.alibaba.com/
> v2: https://lore.kernel.org/all/20240903085643.3393012-1-hongzhen@linux.alibaba.com/
> v1: https://lore.kernel.org/all/20240903073517.3311407-1-hongzhen@linux.alibaba.com/
> ---
>   fsck/main.c | 82 ++++++++++++++++++++++++++++++++++++++++++++++++++---
>   1 file changed, 78 insertions(+), 4 deletions(-)
> 
> diff --git a/fsck/main.c b/fsck/main.c
> index 28f1e7e..d110cdb 100644
> --- a/fsck/main.c
> +++ b/fsck/main.c
> @@ -9,6 +9,7 @@
>   #include <utime.h>
>   #include <unistd.h>
>   #include <sys/stat.h>
> +#include <sys/xattr.h>
>   #include "erofs/print.h"
>   #include "erofs/compress.h"
>   #include "erofs/decompress.h"
> @@ -31,6 +32,7 @@ struct erofsfsck_cfg {
>   	bool overwrite;
>   	bool preserve_owner;
>   	bool preserve_perms;
> +	bool dump_xattrs;
>   };
>   static struct erofsfsck_cfg fsckcfg;
>   
> @@ -48,6 +50,8 @@ static struct option long_options[] = {
>   	{"no-preserve-owner", no_argument, 0, 10},
>   	{"no-preserve-perms", no_argument, 0, 11},
>   	{"offset", required_argument, 0, 12},
> +	{"xattrs", no_argument, 0, 13},
> +	{"no-xattrs", no_argument, 0, 14},
>   	{0, 0, 0, 0},
>   };
>   
> @@ -98,6 +102,7 @@ static void usage(int argc, char **argv)
>   		" --extract[=X]          check if all files are well encoded, optionally\n"
>   		"                        extract to X\n"
>   		" --offset=#             skip # bytes at the beginning of IMAGE\n"
> +		" --[no-]xattrs          whether to dump extended attributes (default on)\n"
>   		"\n"
>   		" -a, -A, -y             no-op, for compatibility with fsck of other filesystems\n"
>   		"\n"
> @@ -225,6 +230,12 @@ static int erofsfsck_parse_options_cfg(int argc, char **argv)
>   				return -EINVAL;
>   			}
>   			break;
> +		case 13:
> +			fsckcfg.dump_xattrs = true;
> +			break;
> +		case 14:
> +			fsckcfg.dump_xattrs = false;
> +			break;
>   		default:
>   			return -EINVAL;
>   		}
> @@ -411,6 +422,60 @@ out:
>   	return ret;
>   }
>   
> +static int erofsfsck_dump_xattrs(struct erofs_inode *inode)
> +{
> +	char *keylst, *key;
> +	ssize_t kllen;
> +	int ret;
> +
> +	kllen = erofs_listxattr(inode, NULL, 0);
> +	if (kllen <= 0)
> +		return kllen;
> +	keylst = malloc(kllen);
> +	if (!keylst)
> +		return -ENOMEM;
> +	ret = erofs_listxattr(inode, keylst, kllen);
> +	if (ret < 0)
> +		goto out;
> +	for (key = keylst; key < keylst + kllen; key += strlen(key) + 1) {
> +		void *value = NULL;
> +		size_t size = 0;
> +
> +		ret = erofs_getxattr(inode, key, NULL, 0);
> +		if (ret < 0)
> +			break;
> +		if (ret) {
> +			size = ret;
> +			value = malloc(size);
> +			if (!value) {
> +				ret = -ENOMEM;
> +				break;
> +			}
> +			ret = erofs_getxattr(inode, key, value, size);
> +			if (ret < 0) {
> +				erofs_err("fail to get xattr %s @ nid %llu",
> +					  key, inode->nid | 0ULL);
> +				free(value);
> +				break;
> +			}
> +			if (fsckcfg.extract_path)
> +				ret = setxattr(fsckcfg.extract_path, key, value,
> +					       size, 0);
> +			else
> +				ret = 0;
> +			free(value);
> +			if (ret) {
> +				erofs_err("fail to set xattr %s @ nid %llu",
> +					  key, inode->nid | 0ULL);
> +				break;
> +			}
> +		}
> +	}
> +out:
> +	free(keylst);
> +	return ret;
> +}
> +
>   static int erofs_verify_inode_data(struct erofs_inode *inode, int outfd)
>   {
>   	struct erofs_map_blocks map = {
> @@ -900,15 +965,23 @@ static int erofsfsck_check_inode(erofs_nid_t pnid, erofs_nid_t nid)
>   		goto out;
>   	}
>   
> -	/* verify xattr field */
> -	ret = erofs_verify_xattr(&inode);
> -	if (ret)
> -		goto out;
> +	if (!fsckcfg.check_decomp) {
> +		/* verify xattr field */
> +		ret = erofs_verify_xattr(&inode);
> +		if (ret)
> +			goto out;
> +	}
>   
>   	ret = erofsfsck_extract_inode(&inode);
>   	if (ret && ret != -ECANCELED)
>   		goto out;
>   
> +	if (fsckcfg.check_decomp && fsckcfg.dump_xattrs) {
> +		ret = erofsfsck_dump_xattrs(&inode);
> +		if (ret)
> +			return ret;
> +	}
> +
>   	/* XXXX: the dir depth should be restricted in order to avoid loops */
>   	if (S_ISDIR(inode.i_mode)) {
>   		struct erofs_dir_context ctx = {
> @@ -955,6 +1028,7 @@ int main(int argc, char *argv[])
>   	fsckcfg.overwrite = false;
>   	fsckcfg.preserve_owner = fsckcfg.superuser;
>   	fsckcfg.preserve_perms = fsckcfg.superuser;
> +	fsckcfg.dump_xattrs = true;
>   
>   	err = erofsfsck_parse_options_cfg(argc, argv);
>   	if (err) {