xattr handlers: Simplify list operation

Change the list operation to only return whether or not an attribute should be listed. Copying the attribute names into the buffer is moved to the callers. Since the result only depends on the dentry and not on the attribute name, we do not pass the attribute name to list operations. Signed-off-by: Andreas Gruenbacher <[email protected]> Signed-off-by: Al Viro <[email protected]>
arthurschreiber · Dec 14, 2015 · 764a5c6 · 764a5c6
1 parent 1046cb1
commit 764a5c6
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Showing 22 changed files with 113 additions and 335 deletions.
diff --git a/fs/ext2/xattr.c b/fs/ext2/xattr.c
@@ -292,16 +292,21 @@ bad_block:	ext2_error(inode->i_sb, "ext2_xattr_list",
 		const struct xattr_handler *handler =
 			ext2_xattr_handler(entry->e_name_index);
 
-		if (handler) {
-			size_t size = handler->list(handler, dentry, buffer,
-						    rest, entry->e_name,
-						    entry->e_name_len);
+		if (handler && (!handler->list || handler->list(dentry))) {
+			const char *prefix = handler->prefix ?: handler->name;
+			size_t prefix_len = strlen(prefix);
+			size_t size = prefix_len + entry->e_name_len + 1;
+
 			if (buffer) {
 				if (size > rest) {
 					error = -ERANGE;
 					goto cleanup;
 				}
-				buffer += size;
+				memcpy(buffer, prefix, prefix_len);
+				buffer += prefix_len;
+				memcpy(buffer, entry->e_name, entry->e_name_len);
+				buffer += entry->e_name_len;
+				*buffer++ = 0;
 			}
 			rest -= size;
 		}

diff --git a/fs/ext2/xattr_security.c b/fs/ext2/xattr_security.c
@@ -7,22 +7,6 @@
 #include <linux/security.h>
 #include "xattr.h"
 
-static size_t
-ext2_xattr_security_list(const struct xattr_handler *handler,
-			 struct dentry *dentry, char *list, size_t list_size,
-			 const char *name, size_t name_len)
-{
-	const int prefix_len = XATTR_SECURITY_PREFIX_LEN;
-	const size_t total_len = prefix_len + name_len + 1;
-
-	if (list && total_len <= list_size) {
-		memcpy(list, XATTR_SECURITY_PREFIX, prefix_len);
-		memcpy(list+prefix_len, name, name_len);
-		list[prefix_len + name_len] = '\0';
-	}
-	return total_len;
-}
-
 static int
 ext2_xattr_security_get(const struct xattr_handler *handler,
 			struct dentry *dentry, const char *name,
@@ -67,7 +51,6 @@ ext2_init_security(struct inode *inode, struct inode *dir,
 
 const struct xattr_handler ext2_xattr_security_handler = {
 	.prefix	= XATTR_SECURITY_PREFIX,
-	.list	= ext2_xattr_security_list,
 	.get	= ext2_xattr_security_get,
 	.set	= ext2_xattr_security_set,
 };
diff --git a/fs/ext2/xattr_trusted.c b/fs/ext2/xattr_trusted.c
@@ -8,23 +8,10 @@
 #include "ext2.h"
 #include "xattr.h"
 
-static size_t
-ext2_xattr_trusted_list(const struct xattr_handler *handler,
-			struct dentry *dentry, char *list, size_t list_size,
-			const char *name, size_t name_len)
+static bool
+ext2_xattr_trusted_list(struct dentry *dentry)
 {
-	const int prefix_len = XATTR_TRUSTED_PREFIX_LEN;
-	const size_t total_len = prefix_len + name_len + 1;
-
-	if (!capable(CAP_SYS_ADMIN))
-		return 0;
-
-	if (list && total_len <= list_size) {
-		memcpy(list, XATTR_TRUSTED_PREFIX, prefix_len);
-		memcpy(list+prefix_len, name, name_len);
-		list[prefix_len + name_len] = '\0';
-	}
-	return total_len;
+	return capable(CAP_SYS_ADMIN);
 }
 
 static int

diff --git a/fs/ext2/xattr_user.c b/fs/ext2/xattr_user.c
@@ -10,23 +10,10 @@
 #include "ext2.h"
 #include "xattr.h"
 
-static size_t
-ext2_xattr_user_list(const struct xattr_handler *handler,
-		     struct dentry *dentry, char *list, size_t list_size,
-		     const char *name, size_t name_len)
+static bool
+ext2_xattr_user_list(struct dentry *dentry)
 {
-	const size_t prefix_len = XATTR_USER_PREFIX_LEN;
-	const size_t total_len = prefix_len + name_len + 1;
-
-	if (!test_opt(dentry->d_sb, XATTR_USER))
-		return 0;
-
-	if (list && total_len <= list_size) {
-		memcpy(list, XATTR_USER_PREFIX, prefix_len);
-		memcpy(list+prefix_len, name, name_len);
-		list[prefix_len + name_len] = '\0';
-	}
-	return total_len;
+	return test_opt(dentry->d_sb, XATTR_USER);
 }
 
 static int

diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
@@ -404,19 +404,24 @@ ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
 		const struct xattr_handler *handler =
 			ext4_xattr_handler(entry->e_name_index);
 
-		if (handler) {
-			size_t size = handler->list(handler, dentry, buffer,
-						    rest, entry->e_name,
-						    entry->e_name_len);
+		if (handler && (!handler->list || handler->list(dentry))) {
+			const char *prefix = handler->prefix ?: handler->name;
+			size_t prefix_len = strlen(prefix);
+			size_t size = prefix_len + entry->e_name_len + 1;
+
 			if (buffer) {
 				if (size > rest)
 					return -ERANGE;
-				buffer += size;
+				memcpy(buffer, prefix, prefix_len);
+				buffer += prefix_len;
+				memcpy(buffer, entry->e_name, entry->e_name_len);
+				buffer += entry->e_name_len;
+				*buffer++ = 0;
 			}
 			rest -= size;
 		}
 	}
-	return buffer_size - rest;
+	return buffer_size - rest;  /* total size */
 }
 
 static int

diff --git a/fs/ext4/xattr_security.c b/fs/ext4/xattr_security.c
@@ -11,23 +11,6 @@
 #include "ext4.h"
 #include "xattr.h"
 
-static size_t
-ext4_xattr_security_list(const struct xattr_handler *handler,
-			 struct dentry *dentry, char *list, size_t list_size,
-			 const char *name, size_t name_len)
-{
-	const size_t prefix_len = sizeof(XATTR_SECURITY_PREFIX)-1;
-	const size_t total_len = prefix_len + name_len + 1;
-
-
-	if (list && total_len <= list_size) {
-		memcpy(list, XATTR_SECURITY_PREFIX, prefix_len);
-		memcpy(list+prefix_len, name, name_len);
-		list[prefix_len + name_len] = '\0';
-	}
-	return total_len;
-}
-
 static int
 ext4_xattr_security_get(const struct xattr_handler *handler,
 			struct dentry *dentry, const char *name,
@@ -75,7 +58,6 @@ ext4_init_security(handle_t *handle, struct inode *inode, struct inode *dir,
 
 const struct xattr_handler ext4_xattr_security_handler = {
 	.prefix	= XATTR_SECURITY_PREFIX,
-	.list	= ext4_xattr_security_list,
 	.get	= ext4_xattr_security_get,
 	.set	= ext4_xattr_security_set,
 };
diff --git a/fs/ext4/xattr_trusted.c b/fs/ext4/xattr_trusted.c
@@ -12,23 +12,10 @@
 #include "ext4.h"
 #include "xattr.h"
 
-static size_t
-ext4_xattr_trusted_list(const struct xattr_handler *handler,
-			struct dentry *dentry, char *list, size_t list_size,
-			const char *name, size_t name_len)
+static bool
+ext4_xattr_trusted_list(struct dentry *dentry)
 {
-	const size_t prefix_len = XATTR_TRUSTED_PREFIX_LEN;
-	const size_t total_len = prefix_len + name_len + 1;
-
-	if (!capable(CAP_SYS_ADMIN))
-		return 0;
-
-	if (list && total_len <= list_size) {
-		memcpy(list, XATTR_TRUSTED_PREFIX, prefix_len);
-		memcpy(list+prefix_len, name, name_len);
-		list[prefix_len + name_len] = '\0';
-	}
-	return total_len;
+	return capable(CAP_SYS_ADMIN);
 }
 
 static int

diff --git a/fs/ext4/xattr_user.c b/fs/ext4/xattr_user.c
@@ -11,23 +11,10 @@
 #include "ext4.h"
 #include "xattr.h"
 
-static size_t
-ext4_xattr_user_list(const struct xattr_handler *handler,
-		     struct dentry *dentry, char *list, size_t list_size,
-		     const char *name, size_t name_len)
+static bool
+ext4_xattr_user_list(struct dentry *dentry)
 {
-	const size_t prefix_len = XATTR_USER_PREFIX_LEN;
-	const size_t total_len = prefix_len + name_len + 1;
-
-	if (!test_opt(dentry->d_sb, XATTR_USER))
-		return 0;
-
-	if (list && total_len <= list_size) {
-		memcpy(list, XATTR_USER_PREFIX, prefix_len);
-		memcpy(list+prefix_len, name, name_len);
-		list[prefix_len + name_len] = '\0';
-	}
-	return total_len;
+	return test_opt(dentry->d_sb, XATTR_USER);
 }
 
 static int

diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c
@@ -25,40 +25,6 @@
 #include "f2fs.h"
 #include "xattr.h"
 
-static size_t f2fs_xattr_generic_list(const struct xattr_handler *handler,
-		struct dentry *dentry, char *list, size_t list_size,
-		const char *name, size_t len)
-{
-	struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
-	const char *prefix;
-	int total_len, prefix_len;
-
-	switch (handler->flags) {
-	case F2FS_XATTR_INDEX_USER:
-		if (!test_opt(sbi, XATTR_USER))
-			return -EOPNOTSUPP;
-		break;
-	case F2FS_XATTR_INDEX_TRUSTED:
-		if (!capable(CAP_SYS_ADMIN))
-			return -EPERM;
-		break;
-	case F2FS_XATTR_INDEX_SECURITY:
-		break;
-	default:
-		return -EINVAL;
-	}
-
-	prefix = xattr_prefix(handler);
-	prefix_len = strlen(prefix);
-	total_len = prefix_len + len + 1;
-	if (list && total_len <= list_size) {
-		memcpy(list, prefix, prefix_len);
-		memcpy(list + prefix_len, name, len);
-		list[prefix_len + len] = '\0';
-	}
-	return total_len;
-}
-
 static int f2fs_xattr_generic_get(const struct xattr_handler *handler,
 		struct dentry *dentry, const char *name, void *buffer,
 		size_t size)
@@ -107,17 +73,16 @@ static int f2fs_xattr_generic_set(const struct xattr_handler *handler,
 					value, size, NULL, flags);
 }
 
-static size_t f2fs_xattr_advise_list(const struct xattr_handler *handler,
-		struct dentry *dentry, char *list, size_t list_size,
-		const char *name, size_t len)
+static bool f2fs_xattr_user_list(struct dentry *dentry)
 {
-	const char *xname = F2FS_SYSTEM_ADVISE_NAME;
-	size_t size;
+	struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
+
+	return test_opt(sbi, XATTR_USER);
+}
 
-	size = strlen(xname) + 1;
-	if (list && size <= list_size)
-		memcpy(list, xname, size);
-	return size;
+static bool f2fs_xattr_trusted_list(struct dentry *dentry)
+{
+	return capable(CAP_SYS_ADMIN);
 }
 
 static int f2fs_xattr_advise_get(const struct xattr_handler *handler,
@@ -175,31 +140,29 @@ int f2fs_init_security(struct inode *inode, struct inode *dir,
 const struct xattr_handler f2fs_xattr_user_handler = {
 	.prefix	= XATTR_USER_PREFIX,
 	.flags	= F2FS_XATTR_INDEX_USER,
-	.list	= f2fs_xattr_generic_list,
+	.list	= f2fs_xattr_user_list,
 	.get	= f2fs_xattr_generic_get,
 	.set	= f2fs_xattr_generic_set,
 };
 
 const struct xattr_handler f2fs_xattr_trusted_handler = {
 	.prefix	= XATTR_TRUSTED_PREFIX,
 	.flags	= F2FS_XATTR_INDEX_TRUSTED,
-	.list	= f2fs_xattr_generic_list,
+	.list	= f2fs_xattr_trusted_list,
 	.get	= f2fs_xattr_generic_get,
 	.set	= f2fs_xattr_generic_set,
 };
 
 const struct xattr_handler f2fs_xattr_advise_handler = {
 	.name	= F2FS_SYSTEM_ADVISE_NAME,
 	.flags	= F2FS_XATTR_INDEX_ADVISE,
-	.list   = f2fs_xattr_advise_list,
 	.get    = f2fs_xattr_advise_get,
 	.set    = f2fs_xattr_advise_set,
 };
 
 const struct xattr_handler f2fs_xattr_security_handler = {
 	.prefix	= XATTR_SECURITY_PREFIX,
 	.flags	= F2FS_XATTR_INDEX_SECURITY,
-	.list	= f2fs_xattr_generic_list,
 	.get	= f2fs_xattr_generic_get,
 	.set	= f2fs_xattr_generic_set,
 };
@@ -447,20 +410,27 @@ ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
 	list_for_each_xattr(entry, base_addr) {
 		const struct xattr_handler *handler =
 			f2fs_xattr_handler(entry->e_name_index);
+		const char *prefix;
+		size_t prefix_len;
 		size_t size;
 
-		if (!handler)
+		if (!handler || (handler->list && !handler->list(dentry)))
 			continue;
 
-		size = handler->list(handler, dentry, buffer, rest,
-				     entry->e_name, entry->e_name_len);
-		if (buffer && size > rest) {
-			error = -ERANGE;
-			goto cleanup;
+		prefix = handler->prefix ?: handler->name;
+		prefix_len = strlen(prefix);
+		size = prefix_len + entry->e_name_len + 1;
+		if (buffer) {
+			if (size > rest) {
+				error = -ERANGE;
+				goto cleanup;
+			}
+			memcpy(buffer, prefix, prefix_len);
+			buffer += prefix_len;
+			memcpy(buffer, entry->e_name, entry->e_name_len);
+			buffer += entry->e_name_len;
+			*buffer++ = 0;
 		}
-
-		if (buffer)
-			buffer += size;
 		rest -= size;
 	}
 	error = buffer_size - rest;

diff --git a/fs/jffs2/security.c b/fs/jffs2/security.c
@@ -64,24 +64,8 @@ static int jffs2_security_setxattr(const struct xattr_handler *handler,
 				 name, buffer, size, flags);
 }
 
-static size_t jffs2_security_listxattr(const struct xattr_handler *handler,
-				       struct dentry *dentry, char *list,
-				       size_t list_size, const char *name,
-				       size_t name_len)
-{
-	size_t retlen = XATTR_SECURITY_PREFIX_LEN + name_len + 1;
-
-	if (list && retlen <= list_size) {
-		strcpy(list, XATTR_SECURITY_PREFIX);
-		strcpy(list + XATTR_SECURITY_PREFIX_LEN, name);
-	}
-
-	return retlen;
-}
-
 const struct xattr_handler jffs2_security_xattr_handler = {
 	.prefix = XATTR_SECURITY_PREFIX,
-	.list = jffs2_security_listxattr,
 	.set = jffs2_security_setxattr,
 	.get = jffs2_security_getxattr
 };