lib/xattr.c - platform/external/erofs-utils - Git at Google

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * erofs_utils/lib/xattr.c
  *
  * Originally contributed by an anonymous person,
  * heavily changed by Li Guifu <blucerlee@gmail.com>
  *                and Gao Xiang <hsiangkao@aol.com>
  */
 #include <stdlib.h>
 #include <sys/xattr.h>
 #ifdef HAVE_LINUX_XATTR_H
 #include <linux/xattr.h>
 #endif
 #include "erofs/print.h"
 #include "erofs/hashtable.h"
 #include "erofs/xattr.h"

 #define EA_HASHTABLE_BITS 16

 struct xattr_item {
 	const char *kvbuf;
 	unsigned int hash[2], len[2], count;
 	u8 prefix;
 	struct hlist_node node;
 };

 struct inode_xattr_node {
 	struct list_head list;
 	struct xattr_item *item;
 };

 static DECLARE_HASHTABLE(ea_hashtable, EA_HASHTABLE_BITS);

 static struct xattr_prefix {
 	const char *prefix;
 	u16 prefix_len;
 } xattr_types[] = {
 	[EROFS_XATTR_INDEX_USER] = {
 		XATTR_USER_PREFIX,
 		XATTR_USER_PREFIX_LEN
 	}, [EROFS_XATTR_INDEX_POSIX_ACL_ACCESS] = {
 		XATTR_NAME_POSIX_ACL_ACCESS,
 		sizeof(XATTR_NAME_POSIX_ACL_ACCESS) - 1
 	}, [EROFS_XATTR_INDEX_POSIX_ACL_DEFAULT] = {
 		XATTR_NAME_POSIX_ACL_DEFAULT,
 		sizeof(XATTR_NAME_POSIX_ACL_DEFAULT) - 1
 	}, [EROFS_XATTR_INDEX_TRUSTED] = {
 		XATTR_TRUSTED_PREFIX,
 		XATTR_TRUSTED_PREFIX_LEN
 	}, [EROFS_XATTR_INDEX_SECURITY] = {
 		XATTR_SECURITY_PREFIX,
 		XATTR_SECURITY_PREFIX_LEN
 	}
 };

 static unsigned int BKDRHash(char *str, unsigned int len)
 {
 	const unsigned int seed = 131313;
 	unsigned int hash = 0;

 	while (len) {
 		hash = hash * seed + (*str++);
 		--len;
 	}
 	return hash;
 }

 static unsigned int xattr_item_hash(u8 prefix, char *buf,
 				    unsigned int len[2], unsigned int hash[2])
 {
 	hash[0] = BKDRHash(buf, len[0]);	/* key */
 	hash[1] = BKDRHash(buf + len[0], len[1]);	/* value */

 	return prefix ^ hash[0] ^ hash[1];
 }

 static unsigned int put_xattritem(struct xattr_item *item)
 {
 	if (item->count > 1)
 		return --item->count;
 	free(item);
 	return 0;
 }

 static struct xattr_item *get_xattritem(u8 prefix, char *kvbuf,
 					unsigned int len[2])
 {
 	struct xattr_item *item;
 	unsigned int hash[2], hkey;

 	hkey = xattr_item_hash(prefix, kvbuf, len, hash);

 	hash_for_each_possible(ea_hashtable, item, node, hkey) {
 		if (prefix == item->prefix &&
 		    item->len[0] == len[0] && item->len[1] == len[1] &&
 		    item->hash[0] == hash[0] && item->hash[1] == hash[1] &&
 		    !memcmp(kvbuf, item->kvbuf, len[0] + len[1])) {
 			free(kvbuf);
 			++item->count;
 			return item;
 		}
 	}

 	item = malloc(sizeof(*item));
 	if (!item) {
 		free(kvbuf);
 		return ERR_PTR(-ENOMEM);
 	}
 	INIT_HLIST_NODE(&item->node);
 	item->count = 1;
 	item->kvbuf = kvbuf;
 	item->len[0] = len[0];
 	item->len[1] = len[1];
 	item->hash[0] = hash[0];
 	item->hash[1] = hash[1];
 	item->prefix = prefix;
 	hash_add(ea_hashtable, &item->node, hkey);
 	return item;
 }

 static bool match_prefix(const char *key, u8 *index, u16 *len)
 {
 	struct xattr_prefix *p;

 	for (p = xattr_types; p < xattr_types + ARRAY_SIZE(xattr_types); ++p) {
 		if (p->prefix && !strncmp(p->prefix, key, p->prefix_len)) {
 			*len = p->prefix_len;
 			*index = p - xattr_types;
 			return true;
 		}
 	}
 	return false;
 }

 static struct xattr_item *parse_one_xattr(const char *path, const char *key,
 					  unsigned int keylen)
 {
 	ssize_t ret;
 	u8 prefix;
 	u16 prefixlen;
 	unsigned int len[2];
 	char *kvbuf;

 	erofs_dbg("parse xattr [%s] of %s", path, key);

 	if (!match_prefix(key, &prefix, &prefixlen))
 		return ERR_PTR(-ENODATA);

 	DBG_BUGON(keylen < prefixlen);

 	/* determine length of the value */
 	ret = lgetxattr(path, key, NULL, 0);
 	if (ret < 0)
 		return ERR_PTR(-errno);
 	len[1] = ret;

 	/* allocate key-value buffer */
 	len[0] = keylen - prefixlen;

 	kvbuf = malloc(len[0] + len[1]);
 	if (!kvbuf)
 		return ERR_PTR(-ENOMEM);

 	memcpy(kvbuf, key + prefixlen, len[0]);
 	if (len[1]) {
 		/* copy value to buffer */
 		ret = lgetxattr(path, key, kvbuf + len[0], len[1]);
 		if (ret < 0) {
 			free(kvbuf);
 			return ERR_PTR(-errno);
 		}
 		if (len[1] != ret) {
 			erofs_err("size of xattr value got changed just now (%u-> %ld)",
 				  len[1], (long)ret);
 			len[1] = ret;
 		}
 	}
 	return get_xattritem(prefix, kvbuf, len);
 }

 static int inode_xattr_add(struct list_head *hlist, struct xattr_item *item)
 {
 	struct inode_xattr_node *node = malloc(sizeof(*node));

 	if (!node)
 		return -ENOMEM;
 	init_list_head(&node->list);
 	node->item = item;
 	list_add(&node->list, hlist);
 	return 0;
 }

 static int read_xattrs_from_file(const char *path, struct list_head *ixattrs)
 {
 	int ret = 0;
 	char *keylst, *key;
 	ssize_t kllen = llistxattr(path, NULL, 0);

 	if (kllen < 0 && errno != ENODATA) {
 		erofs_err("llistxattr to get the size of names for %s failed",
 			  path);
 		return -errno;
 	}
 	if (kllen <= 1)
 		return 0;

 	keylst = malloc(kllen);
 	if (!keylst)
 		return -ENOMEM;

 	/* copy the list of attribute keys to the buffer.*/
 	kllen = llistxattr(path, keylst, kllen);
 	if (kllen < 0) {
 		erofs_err("llistxattr to get names for %s failed", path);
 		ret = -errno;
 		goto err;
 	}

 	/*
 	 * loop over the list of zero terminated strings with the
 	 * attribute keys. Use the remaining buffer length to determine
 	 * the end of the list.
 	 */
 	key = keylst;
 	while (kllen > 0) {
 		unsigned int keylen = strlen(key);
 		struct xattr_item *item = parse_one_xattr(path, key, keylen);

 		if (IS_ERR(item)) {
 			ret = PTR_ERR(item);
 			goto err;
 		}

 		if (ixattrs) {
 			ret = inode_xattr_add(ixattrs, item);
 			if (ret < 0)
 				goto err;
 		}
 		kllen -= keylen + 1;
 		key += keylen + 1;
 	}
 err:
 	free(keylst);
 	return ret;

 }

 int erofs_prepare_xattr_ibody(const char *path, struct list_head *ixattrs)
 {
 	int ret;
 	struct inode_xattr_node *node;

 	/* check if xattr is disabled */
 	if (cfg.c_inline_xattr_tolerance < 0)
 		return 0;

 	ret = read_xattrs_from_file(path, ixattrs);
 	if (ret < 0)
 		return ret;

 	if (list_empty(ixattrs))
 		return 0;

 	/* get xattr ibody size */
 	ret = sizeof(struct erofs_xattr_ibody_header);
 	list_for_each_entry(node, ixattrs, list) {
 		const struct xattr_item *item = node->item;

 		ret += sizeof(struct erofs_xattr_entry);
 		ret = EROFS_XATTR_ALIGN(ret + item->len[0] + item->len[1]);
 	}
 	return ret;
 }

 char *erofs_export_xattr_ibody(struct list_head *ixattrs, unsigned int size)
 {
 	struct inode_xattr_node *node, *n;
 	struct erofs_xattr_ibody_header *header;
 	unsigned int p;
 	char *buf = calloc(1, size);

 	if (!buf)
 		return ERR_PTR(-ENOMEM);

 	header = (struct erofs_xattr_ibody_header *)buf;
 	header->h_shared_count = 0;

 	p = sizeof(struct erofs_xattr_ibody_header);
 	list_for_each_entry_safe(node, n, ixattrs, list) {
 		struct xattr_item *const item = node->item;
 		const struct erofs_xattr_entry entry = {
 			.e_name_index = item->prefix,
 			.e_name_len = item->len[0],
 			.e_value_size = cpu_to_le16(item->len[1])
 		};

 		memcpy(buf + p, &entry, sizeof(entry));
 		p += sizeof(struct erofs_xattr_entry);
 		memcpy(buf + p, item->kvbuf, item->len[0] + item->len[1]);
 		p = EROFS_XATTR_ALIGN(p + item->len[0] + item->len[1]);

 		list_del(&node->list);
 		free(node);
 		put_xattritem(item);
 	}
 	DBG_BUGON(p > size);
 	return buf;
 }
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* erofs_utils/lib/xattr.c
	*
	* Originally contributed by an anonymous person,
	* heavily changed by Li Guifu <blucerlee@gmail.com>
	* and Gao Xiang <hsiangkao@aol.com>
	*/
	#include <stdlib.h>
	#include <sys/xattr.h>
	#ifdef HAVE_LINUX_XATTR_H
	#include <linux/xattr.h>
	#endif
	#include "erofs/print.h"
	#include "erofs/hashtable.h"
	#include "erofs/xattr.h"

	#define EA_HASHTABLE_BITS 16

	struct xattr_item {
	const char *kvbuf;
	unsigned int hash[2], len[2], count;
	u8 prefix;
	struct hlist_node node;
	};

	struct inode_xattr_node {
	struct list_head list;
	struct xattr_item *item;
	};

	static DECLARE_HASHTABLE(ea_hashtable, EA_HASHTABLE_BITS);

	static struct xattr_prefix {
	const char *prefix;
	u16 prefix_len;
	} xattr_types[] = {
	[EROFS_XATTR_INDEX_USER] = {
	XATTR_USER_PREFIX,
	XATTR_USER_PREFIX_LEN
	}, [EROFS_XATTR_INDEX_POSIX_ACL_ACCESS] = {
	XATTR_NAME_POSIX_ACL_ACCESS,
	sizeof(XATTR_NAME_POSIX_ACL_ACCESS) - 1
	}, [EROFS_XATTR_INDEX_POSIX_ACL_DEFAULT] = {
	XATTR_NAME_POSIX_ACL_DEFAULT,
	sizeof(XATTR_NAME_POSIX_ACL_DEFAULT) - 1
	}, [EROFS_XATTR_INDEX_TRUSTED] = {
	XATTR_TRUSTED_PREFIX,
	XATTR_TRUSTED_PREFIX_LEN
	}, [EROFS_XATTR_INDEX_SECURITY] = {
	XATTR_SECURITY_PREFIX,
	XATTR_SECURITY_PREFIX_LEN
	}
	};

	static unsigned int BKDRHash(char *str, unsigned int len)
	{
	const unsigned int seed = 131313;
	unsigned int hash = 0;

	while (len) {
	hash = hash * seed + (*str++);
	--len;
	}
	return hash;
	}

	static unsigned int xattr_item_hash(u8 prefix, char *buf,
	unsigned int len[2], unsigned int hash[2])
	{
	hash[0] = BKDRHash(buf, len[0]); /* key */
	hash[1] = BKDRHash(buf + len[0], len[1]); /* value */

	return prefix ^ hash[0] ^ hash[1];
	}

	static unsigned int put_xattritem(struct xattr_item *item)
	{
	if (item->count > 1)
	return --item->count;
	free(item);
	return 0;
	}

	static struct xattr_item get_xattritem(u8 prefix, char kvbuf,
	unsigned int len[2])
	{
	struct xattr_item *item;
	unsigned int hash[2], hkey;

	hkey = xattr_item_hash(prefix, kvbuf, len, hash);

	hash_for_each_possible(ea_hashtable, item, node, hkey) {
	if (prefix == item->prefix &&
	item->len[0] == len[0] && item->len[1] == len[1] &&
	item->hash[0] == hash[0] && item->hash[1] == hash[1] &&
	!memcmp(kvbuf, item->kvbuf, len[0] + len[1])) {
	free(kvbuf);
	++item->count;
	return item;
	}
	}

	item = malloc(sizeof(*item));
	if (!item) {
	free(kvbuf);
	return ERR_PTR(-ENOMEM);
	}
	INIT_HLIST_NODE(&item->node);
	item->count = 1;
	item->kvbuf = kvbuf;
	item->len[0] = len[0];
	item->len[1] = len[1];
	item->hash[0] = hash[0];
	item->hash[1] = hash[1];
	item->prefix = prefix;
	hash_add(ea_hashtable, &item->node, hkey);
	return item;
	}

	static bool match_prefix(const char key, u8 index, u16 *len)
	{
	struct xattr_prefix *p;

	for (p = xattr_types; p < xattr_types + ARRAY_SIZE(xattr_types); ++p) {
	if (p->prefix && !strncmp(p->prefix, key, p->prefix_len)) {
	*len = p->prefix_len;
	*index = p - xattr_types;
	return true;
	}
	}
	return false;
	}

	static struct xattr_item parse_one_xattr(const char path, const char *key,
	unsigned int keylen)
	{
	ssize_t ret;
	u8 prefix;
	u16 prefixlen;
	unsigned int len[2];
	char *kvbuf;

	erofs_dbg("parse xattr [%s] of %s", path, key);

	if (!match_prefix(key, &prefix, &prefixlen))
	return ERR_PTR(-ENODATA);

	DBG_BUGON(keylen < prefixlen);

	/* determine length of the value */
	ret = lgetxattr(path, key, NULL, 0);
	if (ret < 0)
	return ERR_PTR(-errno);
	len[1] = ret;

	/* allocate key-value buffer */
	len[0] = keylen - prefixlen;

	kvbuf = malloc(len[0] + len[1]);
	if (!kvbuf)
	return ERR_PTR(-ENOMEM);

	memcpy(kvbuf, key + prefixlen, len[0]);
	if (len[1]) {
	/* copy value to buffer */
	ret = lgetxattr(path, key, kvbuf + len[0], len[1]);
	if (ret < 0) {
	free(kvbuf);
	return ERR_PTR(-errno);
	}
	if (len[1] != ret) {
	erofs_err("size of xattr value got changed just now (%u-> %ld)",
	len[1], (long)ret);
	len[1] = ret;
	}
	}
	return get_xattritem(prefix, kvbuf, len);
	}

	static int inode_xattr_add(struct list_head hlist, struct xattr_item item)
	{
	struct inode_xattr_node node = malloc(sizeof(node));

	if (!node)
	return -ENOMEM;
	init_list_head(&node->list);
	node->item = item;
	list_add(&node->list, hlist);
	return 0;
	}

	static int read_xattrs_from_file(const char path, struct list_head ixattrs)
	{
	int ret = 0;
	char keylst, key;
	ssize_t kllen = llistxattr(path, NULL, 0);

	if (kllen < 0 && errno != ENODATA) {
	erofs_err("llistxattr to get the size of names for %s failed",
	path);
	return -errno;
	}
	if (kllen <= 1)
	return 0;

	keylst = malloc(kllen);
	if (!keylst)
	return -ENOMEM;

	/* copy the list of attribute keys to the buffer.*/
	kllen = llistxattr(path, keylst, kllen);
	if (kllen < 0) {
	erofs_err("llistxattr to get names for %s failed", path);
	ret = -errno;
	goto err;
	}

	/*
	* loop over the list of zero terminated strings with the
	* attribute keys. Use the remaining buffer length to determine
	* the end of the list.
	*/
	key = keylst;
	while (kllen > 0) {
	unsigned int keylen = strlen(key);
	struct xattr_item *item = parse_one_xattr(path, key, keylen);

	if (IS_ERR(item)) {
	ret = PTR_ERR(item);
	goto err;
	}

	if (ixattrs) {
	ret = inode_xattr_add(ixattrs, item);
	if (ret < 0)
	goto err;
	}
	kllen -= keylen + 1;
	key += keylen + 1;
	}
	err:
	free(keylst);
	return ret;

	}

	int erofs_prepare_xattr_ibody(const char path, struct list_head ixattrs)
	{
	int ret;
	struct inode_xattr_node *node;

	/* check if xattr is disabled */
	if (cfg.c_inline_xattr_tolerance < 0)
	return 0;

	ret = read_xattrs_from_file(path, ixattrs);
	if (ret < 0)
	return ret;

	if (list_empty(ixattrs))
	return 0;

	/* get xattr ibody size */
	ret = sizeof(struct erofs_xattr_ibody_header);
	list_for_each_entry(node, ixattrs, list) {
	const struct xattr_item *item = node->item;

	ret += sizeof(struct erofs_xattr_entry);
	ret = EROFS_XATTR_ALIGN(ret + item->len[0] + item->len[1]);
	}
	return ret;
	}

	char erofs_export_xattr_ibody(struct list_head ixattrs, unsigned int size)
	{
	struct inode_xattr_node node, n;
	struct erofs_xattr_ibody_header *header;
	unsigned int p;
	char *buf = calloc(1, size);

	if (!buf)
	return ERR_PTR(-ENOMEM);

	header = (struct erofs_xattr_ibody_header *)buf;
	header->h_shared_count = 0;

	p = sizeof(struct erofs_xattr_ibody_header);
	list_for_each_entry_safe(node, n, ixattrs, list) {
	struct xattr_item *const item = node->item;
	const struct erofs_xattr_entry entry = {
	.e_name_index = item->prefix,
	.e_name_len = item->len[0],
	.e_value_size = cpu_to_le16(item->len[1])
	};

	memcpy(buf + p, &entry, sizeof(entry));
	p += sizeof(struct erofs_xattr_entry);
	memcpy(buf + p, item->kvbuf, item->len[0] + item->len[1]);
	p = EROFS_XATTR_ALIGN(p + item->len[0] + item->len[1]);

	list_del(&node->list);
	free(node);
	put_xattritem(item);
	}
	DBG_BUGON(p > size);
	return buf;
	}