[PATCH v10 1/2] erofs-utils: lib: expose erofs_xattr_prefix_matches()

[PATCH v10 1/2] erofs-utils: lib: expose erofs_xattr_prefix_matches()

[Hongzhen Luo]

Prepare for the feature of exporting extended attributes for
`fsck.erofs`.

Signed-off-by: Hongzhen Luo <hongzhen@linux.alibaba.com>
---
v5: No changes.
v4: https://lore.kernel.org/all/20240913064913.537850-1-hongzhen@linux.alibaba.com/
v3: https://lore.kernel.org/all/20240912131108.3742683-1-hongzhen@linux.alibaba.com/
v2: https://lore.kernel.org/all/20240906095853.3167228-1-hongzhen@linux.alibaba.com/
v1: https://lore.kernel.org/all/20240906083849.3090392-1-hongzhen@linux.alibaba.com/
---
 include/erofs/xattr.h |  3 +++
 lib/xattr.c           | 12 +++++++-----
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/include/erofs/xattr.h b/include/erofs/xattr.h
index 7643611..804f565 100644
--- a/include/erofs/xattr.h
+++ b/include/erofs/xattr.h
@@ -61,6 +61,9 @@ void erofs_clear_opaque_xattr(struct erofs_inode *inode);
 int erofs_set_origin_xattr(struct erofs_inode *inode);
 int erofs_read_xattrs_from_disk(struct erofs_inode *inode);
 
+bool erofs_xattr_prefix_matches(const char *key, unsigned int *index,
+				unsigned int *len);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/xattr.c b/lib/xattr.c
index 9f31f2d..63c7fce 100644
--- a/lib/xattr.c
+++ b/lib/xattr.c
@@ -138,8 +138,8 @@ struct ea_type_node {
 static LIST_HEAD(ea_name_prefixes);
 static unsigned int ea_prefix_count;
 
-static bool match_prefix(const char *key, unsigned int *index,
-			 unsigned int *len)
+bool erofs_xattr_prefix_matches(const char *key, unsigned int *index,
+				unsigned int *len)
 {
 	struct xattr_prefix *p;
 
@@ -196,7 +196,8 @@ static struct xattr_item *get_xattritem(char *kvbuf, unsigned int len[2])
 	if (!item)
 		return ERR_PTR(-ENOMEM);
 
-	if (!match_prefix(kvbuf, &item->base_index, &item->prefix_len)) {
+	if (!erofs_xattr_prefix_matches(kvbuf, &item->base_index,
+					&item->prefix_len)) {
 		free(item);
 		return ERR_PTR(-ENODATA);
 	}
@@ -1425,7 +1426,7 @@ int erofs_getxattr(struct erofs_inode *vi, const char *name, char *buffer,
 	if (ret)
 		return ret;
 
-	if (!match_prefix(name, &prefix, &prefixlen))
+	if (!erofs_xattr_prefix_matches(name, &prefix, &prefixlen))
 		return -ENODATA;
 
 	it.it.sbi = vi->sbi;
@@ -1600,7 +1601,8 @@ int erofs_xattr_insert_name_prefix(const char *prefix)
 	if (!tnode)
 		return -ENOMEM;
 
-	if (!match_prefix(prefix, &tnode->base_index, &tnode->base_len)) {
+	if (!erofs_xattr_prefix_matches(prefix, &tnode->base_index,
+					&tnode->base_len)) {
 		free(tnode);
 		return -ENODATA;
 	}
-- 
2.43.5

[PATCH v10 2/2] erofs-utils: fsck: introduce exporting xattrs

[Hongzhen Luo]

Currently `fsck --extract` does not support exporting
extended attributes. This patch adds the `--xattrs` option
to dump extended attributes and the `--no-xattrs` option to
omit them (the default behavior).

Signed-off-by: Hongzhen Luo <hongzhen@linux.alibaba.com>
---
v10: Added error message when erofs_getxattr() returns <= 0.
v9: https://lore.kernel.org/all/20240913064913.537850-2-hongzhen@linux.alibaba.com/
v8: https://lore.kernel.org/all/20240912131108.3742683-2-hongzhen@linux.alibaba.com/
v7: https://lore.kernel.org/all/20240906095853.3167228-2-hongzhen@linux.alibaba.com/
v6: https://lore.kernel.org/all/20240906083849.3090392-2-hongzhen@linux.alibaba.com/
v5: https://lore.kernel.org/all/20240906022206.2725584-1-hongzhen@linux.alibaba.com/
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      | 111 +++++++++++++++++++++++++++++++++++++++++++++--
 man/fsck.erofs.1 |   3 ++
 2 files changed, 110 insertions(+), 4 deletions(-)

diff --git a/fsck/main.c b/fsck/main.c
index 28f1e7e..392318c 100644
--- a/fsck/main.c
+++ b/fsck/main.c
@@ -9,10 +9,12 @@
 #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"
 #include "erofs/dir.h"
+#include "erofs/xattr.h"
 #include "../lib/compressor.h"
 
 static int erofsfsck_check_inode(erofs_nid_t pnid, erofs_nid_t nid);
@@ -31,6 +33,7 @@ struct erofsfsck_cfg {
 	bool overwrite;
 	bool preserve_owner;
 	bool preserve_perms;
+	bool dump_xattrs;
 };
 static struct erofsfsck_cfg fsckcfg;
 
@@ -48,6 +51,8 @@ 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 +103,7 @@ 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 off)\n"
 		"\n"
 		" -a, -A, -y             no-op, for compatibility with fsck of other filesystems\n"
 		"\n"
@@ -225,6 +231,12 @@ 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 +423,88 @@ out:
 	return ret;
 }
 
+static int erofsfsck_dump_xattrs(struct erofs_inode *inode)
+{
+	static bool ignore_xattrs = false;
+	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 != kllen) {
+		erofs_err("failed to list xattrs @ nid %llu",
+			  inode->nid | 0ULL);
+		ret = -EINVAL;
+		goto out;
+	}
+	ret = 0;
+	for (key = keylst; key < keylst + kllen; key += strlen(key) + 1) {
+		unsigned int index, len;
+		void *value = NULL;
+		size_t size = 0;
+
+		ret = erofs_getxattr(inode, key, NULL, 0);
+		if (ret <= 0) {
+			DBG_BUGON(1);
+			erofs_err("failed to get xattr value size of `%s` @ nid %llu",
+				  key, inode->nid | 0ULL);
+			break;
+		}
+		size = ret;
+		value = malloc(size);
+		if (!value) {
+			ret = -ENOMEM;
+			break;
+		}
+		ret = erofs_getxattr(inode, key, value, size);
+		if (ret < 0) {
+			erofs_err("failed to get xattr `%s` @ nid %llu, because of `%s`", key,
+				  inode->nid | 0ULL, erofs_strerror(ret));
+			free(value);
+			break;
+		}
+		if (fsckcfg.extract_path)
+			ret = lsetxattr(fsckcfg.extract_path, key, value, size,
+					0);
+		else
+			ret = 0;
+		free(value);
+		if (ret == -EPERM && !fsckcfg.superuser) {
+			if (__erofs_unlikely(!erofs_xattr_prefix_matches(key,
+					&index, &len))) {
+				erofs_err("failed to match the prefix of `%s` @ nid %llu",
+					  key, inode->nid | 0ULL);
+				ret = -EINVAL;
+				break;
+			}
+			if (index != EROFS_XATTR_INDEX_USER) {
+				if (!ignore_xattrs) {
+					erofs_warn("ignored xattr `%s` @ nid %llu, due to non-superuser",
+						   key, inode->nid | 0ULL);
+					ignore_xattrs = true;
+				}
+				ret = 0;
+				continue;
+			}
+
+		}
+		if (ret) {
+			erofs_err("failed to set xattr `%s` @ nid %llu because of `%s`",
+				  key, inode->nid | 0ULL, erofs_strerror(ret));
+			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 +994,23 @@ 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 && fsckcfg.dump_xattrs)) {
+		/* 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 +1057,7 @@ int main(int argc, char *argv[])
 	fsckcfg.overwrite = false;
 	fsckcfg.preserve_owner = fsckcfg.superuser;
 	fsckcfg.preserve_perms = fsckcfg.superuser;
+	fsckcfg.dump_xattrs = false;
 
 	err = erofsfsck_parse_options_cfg(argc, argv);
 	if (err) {
diff --git a/man/fsck.erofs.1 b/man/fsck.erofs.1
index 393ae9e..af0e6ab 100644
--- a/man/fsck.erofs.1
+++ b/man/fsck.erofs.1
@@ -34,6 +34,9 @@ take a long time depending on the image size.
 
 Optionally extract contents of the \fIIMAGE\fR to \fIdirectory\fR.
 .TP
+.BI "--[no-]xattrs"
+Whether to dump extended attributes during extraction (default off).
+.TP
 \fB\-h\fR, \fB\-\-help\fR
 Display help string and exit.
 .TP
-- 
2.43.5

Re: [PATCH v10 2/2] erofs-utils: fsck: introduce exporting xattrs

[Gao Xiang]

On 2024/9/13 15:21, Hongzhen Luo wrote:
> Currently `fsck --extract` does not support exporting
> extended attributes. This patch adds the `--xattrs` option
> to dump extended attributes and the `--no-xattrs` option to
> omit them (the default behavior).
> 
> Signed-off-by: Hongzhen Luo <hongzhen@linux.alibaba.com>
> ---

It fails to build on MacOS, I've applied the following fix manually:

diff --git a/configure.ac b/configure.ac
index 945e254..9c1657b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -260,6 +260,7 @@ AC_CHECK_FUNCS(m4_flatten([
  	gettimeofday
  	lgetxattr
  	llistxattr
+	lsetxattr
  	memset
  	realpath
  	lseek64
diff --git a/fsck/main.c b/fsck/main.c
index b514a63..f20b767 100644
--- a/fsck/main.c
+++ b/fsck/main.c
@@ -470,8 +470,15 @@ static int erofsfsck_dump_xattrs(struct erofs_inode *inode)
  			break;
  		}
  		if (fsckcfg.extract_path)
+#ifdef HAVE_LSETXATTR
  			ret = lsetxattr(fsckcfg.extract_path, key, value, size,
  					0);
+#elif defined(__APPLE__)
+			ret = setxattr(fsckcfg.extract_path, key, value, size,
+				       0, XATTR_NOFOLLOW);
+#else
+			ret = -EOPNOTSUPP;
+#endif
  		else
  			ret = 0;
  		free(value);

Thanks,
Gao Xiang