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Message-ID: <20131012090821.GH6462@gmail.com>
Date: Sat, 12 Oct 2013 17:08:21 +0800
From: Zheng Liu <gnehzuil.liu@...il.com>
To: "Darrick J. Wong" <darrick.wong@...cle.com>
Cc: linux-ext4@...r.kernel.org, Zheng Liu <wenqing.lz@...bao.com>,
Theodore Ts'o <tytso@....edu>
Subject: Re: [PATCH v1 03/22] libext2fs: add functions to operate on extended
attribute
On Sat, Oct 12, 2013 at 02:02:35AM -0700, Darrick J. Wong wrote:
[...]
> > > > Sorry, I still havn't had a chance to take a closer look at your patch
> > > > set for e2fsprogs. I will review it ASAP.
> > >
> > > Ok. I'm getting ready to re-spam the mailing list with some more fixes, so you
> > > can relax for a day or two. There were some bugs handling inode_size=128.
> >
> > Welcome to flush my mail box. :-p
>
> He he he there are 24 of those patches... I got lucky and Ted picked a few more
> tonight. :)
Great! I will take a closer look at your patch.
Thanks,
- Zheng
>
> --D
>
> Well, if you're curious, here's the latest xattr API patch. I wonder if the
> minimum size of the inode ought to be EXT2_GOOD_OLD_SIZE + i_extra_isize + 8
> bytes (to fit the EA magic and the magic zero that says "end of keys")? But
> it's too late at night to think.
>
> From: Darrick J. Wong <darrick.wong@...cle.com>
> Subject: [PATCH] libext2fs: support modifying arbitrary extended attributes
>
> Add functions to allow clients to get, set, and remove extended
> attributes from any file. It also supports modifying EAs living in
> i_file_acl.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@...cle.com>
> ---
> lib/ext2fs/ext2_err.et.in | 18 +
> lib/ext2fs/ext2fs.h | 28 ++
> lib/ext2fs/ext_attr.c | 742 +++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 788 insertions(+)
>
> diff --git a/lib/ext2fs/ext2_err.et.in b/lib/ext2fs/ext2_err.et.in
> index c547a2c..262f4a4 100644
> --- a/lib/ext2fs/ext2_err.et.in
> +++ b/lib/ext2fs/ext2_err.et.in
> @@ -479,4 +479,22 @@ ec EXT2_ET_FILE_EXISTS,
> ec EXT2_ET_BLOCK_BITMAP_CSUM_INVALID,
> "Block bitmap checksum does not match bitmap"
>
> +ec EXT2_ET_EA_BAD_NAME_LEN,
> + "Extended attribute has an invalid name length"
> +
> +ec EXT2_ET_EA_BAD_VALUE_SIZE,
> + "Extended attribute has an invalid value length"
> +
> +ec EXT2_ET_BAD_EA_HASH,
> + "Extended attribute has an incorrect hash"
> +
> +ec EXT2_ET_BAD_EA_HEADER,
> + "Extended attribute block has a bad header"
> +
> +ec EXT2_ET_EA_KEY_NOT_FOUND,
> + "Extended attribute key not found"
> +
> +ec EXT2_ET_EA_NO_SPACE,
> + "Insufficient space to store extended attribute data"
> +
> end
> diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
> index c280ea0..09d3d4c 100644
> --- a/lib/ext2fs/ext2fs.h
> +++ b/lib/ext2fs/ext2fs.h
> @@ -637,6 +637,13 @@ typedef struct stat ext2fs_struct_stat;
> #define EXT2_FLAG_FLUSH_NO_SYNC 1
>
> /*
> + * Modify and iterate extended attributes
> + */
> +struct ext2_xattr_handle;
> +#define XATTR_ABORT 1
> +#define XATTR_CHANGED 2
> +
> +/*
> * function prototypes
> */
> static inline int ext2fs_has_group_desc_csum(ext2_filsys fs)
> @@ -1145,6 +1152,27 @@ extern errcode_t ext2fs_adjust_ea_refcount3(ext2_filsys fs, blk64_t blk,
> char *block_buf,
> int adjust, __u32 *newcount,
> ext2_ino_t inum);
> +errcode_t ext2fs_xattrs_expand(struct ext2_xattr_handle *h,
> + unsigned int expandby);
> +errcode_t ext2fs_xattrs_write(struct ext2_xattr_handle *handle);
> +errcode_t ext2fs_xattrs_read(struct ext2_xattr_handle *handle);
> +errcode_t ext2fs_xattrs_iterate(struct ext2_xattr_handle *h,
> + int (*func)(char *name, char *value,
> + void *data),
> + void *data);
> +errcode_t ext2fs_xattr_get(struct ext2_xattr_handle *h, const char *key,
> + void **value, unsigned int *value_len);
> +errcode_t ext2fs_xattr_set(struct ext2_xattr_handle *handle,
> + const char *key,
> + const void *value,
> + unsigned int value_len);
> +errcode_t ext2fs_xattr_remove(struct ext2_xattr_handle *handle,
> + const char *key);
> +errcode_t ext2fs_xattrs_open(ext2_filsys fs, ext2_ino_t ino,
> + struct ext2_xattr_handle **handle);
> +errcode_t ext2fs_xattrs_close(struct ext2_xattr_handle **handle);
> +errcode_t ext2fs_free_ext_attr(ext2_filsys fs, ext2_ino_t ino,
> + struct ext2_inode_large *inode);
>
> /* extent.c */
> extern errcode_t ext2fs_extent_header_verify(void *ptr, int size);
> diff --git a/lib/ext2fs/ext_attr.c b/lib/ext2fs/ext_attr.c
> index 9649a14..59894ab 100644
> --- a/lib/ext2fs/ext_attr.c
> +++ b/lib/ext2fs/ext_attr.c
> @@ -186,3 +186,745 @@ errcode_t ext2fs_adjust_ea_refcount(ext2_filsys fs, blk_t blk,
> return ext2fs_adjust_ea_refcount2(fs, blk, block_buf, adjust,
> newcount);
> }
> +
> +/* Manipulate the contents of extended attribute regions */
> +struct ext2_xattr {
> + char *name;
> + void *value;
> + unsigned int value_len;
> +};
> +
> +struct ext2_xattr_handle {
> + ext2_filsys fs;
> + struct ext2_xattr *attrs;
> + unsigned int length;
> + ext2_ino_t ino;
> + int dirty;
> +};
> +
> +errcode_t ext2fs_xattrs_expand(struct ext2_xattr_handle *h,
> + unsigned int expandby)
> +{
> + struct ext2_xattr *new_attrs;
> + errcode_t err;
> +
> + err = ext2fs_get_arrayzero(h->length + expandby,
> + sizeof(struct ext2_xattr), &new_attrs);
> + if (err)
> + return err;
> +
> + memcpy(new_attrs, h->attrs, h->length * sizeof(struct ext2_xattr));
> + ext2fs_free_mem(&h->attrs);
> + h->length += expandby;
> + h->attrs = new_attrs;
> +
> + return 0;
> +}
> +
> +struct ea_name_index {
> + int index;
> + const char *name;
> +};
> +
> +static struct ea_name_index ea_names[] = {
> + {1, "user."},
> + {2, "system.posix_acl_access"},
> + {3, "system.posix_acl_default"},
> + {4, "trusted."},
> + {6, "security."},
> + {7, "system."},
> + {0, NULL},
> +};
> +
> +static const char *find_ea_prefix(int index)
> +{
> + struct ea_name_index *e;
> +
> + for (e = ea_names; e->name; e++)
> + if (e->index == index)
> + return e->name;
> +
> + return NULL;
> +}
> +
> +static int find_ea_index(const char *fullname, char **name, int *index)
> +{
> + struct ea_name_index *e;
> +
> + for (e = ea_names; e->name; e++)
> + if (memcmp(fullname, e->name, strlen(e->name)) == 0) {
> + *name = (char *)fullname + strlen(e->name);
> + *index = e->index;
> + return 1;
> + }
> + return 0;
> +}
> +
> +errcode_t ext2fs_free_ext_attr(ext2_filsys fs, ext2_ino_t ino,
> + struct ext2_inode_large *inode)
> +{
> + struct ext2_ext_attr_header *header;
> + void *block_buf = NULL;
> + dgrp_t grp;
> + blk64_t blk, goal;
> + errcode_t err;
> +
> + /* Do we already have an EA block? */
> + blk = ext2fs_file_acl_block(fs, (struct ext2_inode *)inode);
> + if (blk == 0)
> + return 0;
> +
> + /* Find block, zero it, write back */
> + if ((blk < fs->super->s_first_data_block) ||
> + (blk >= ext2fs_blocks_count(fs->super))) {
> + err = EXT2_ET_BAD_EA_BLOCK_NUM;
> + goto out;
> + }
> +
> + err = ext2fs_get_mem(fs->blocksize, &block_buf);
> + if (err)
> + goto out;
> +
> + err = ext2fs_read_ext_attr3(fs, blk, block_buf, ino);
> + if (err)
> + goto out2;
> +
> + header = (struct ext2_ext_attr_header *) block_buf;
> + if (header->h_magic != EXT2_EXT_ATTR_MAGIC) {
> + err = EXT2_ET_BAD_EA_HEADER;
> + goto out2;
> + }
> +
> + header->h_refcount--;
> + err = ext2fs_write_ext_attr3(fs, blk, block_buf, ino);
> + if (err)
> + goto out2;
> +
> + /* Erase link to block */
> + ext2fs_file_acl_block_set(fs, (struct ext2_inode *)inode, 0);
> + if (header->h_refcount == 0)
> + ext2fs_block_alloc_stats2(fs, blk, -1);
> +out2:
> + ext2fs_free_mem(&block_buf);
> +out:
> + return err;
> +}
> +
> +static errcode_t prep_ea_block_for_write(ext2_filsys fs, ext2_ino_t ino,
> + struct ext2_inode_large *inode)
> +{
> + struct ext2_ext_attr_header *header;
> + void *block_buf = NULL;
> + dgrp_t grp;
> + blk64_t blk, goal;
> + errcode_t err;
> +
> + /* Do we already have an EA block? */
> + blk = ext2fs_file_acl_block(fs, (struct ext2_inode *)inode);
> + if (blk != 0) {
> + if ((blk < fs->super->s_first_data_block) ||
> + (blk >= ext2fs_blocks_count(fs->super))) {
> + err = EXT2_ET_BAD_EA_BLOCK_NUM;
> + goto out;
> + }
> +
> + err = ext2fs_get_mem(fs->blocksize, &block_buf);
> + if (err)
> + goto out;
> +
> + err = ext2fs_read_ext_attr3(fs, blk, block_buf, ino);
> + if (err)
> + goto out2;
> +
> + header = (struct ext2_ext_attr_header *) block_buf;
> + if (header->h_magic != EXT2_EXT_ATTR_MAGIC) {
> + err = EXT2_ET_BAD_EA_HEADER;
> + goto out2;
> + }
> +
> + /* Single-user block. We're done here. */
> + if (header->h_refcount == 1)
> + return 0;
> +
> + /* We need to CoW the block. */
> + header->h_refcount--;
> + err = ext2fs_write_ext_attr3(fs, blk, block_buf, ino);
> + if (err)
> + goto out2;
> + } else {
> + /* No block, we must increment i_blocks */
> + err = ext2fs_iblk_add_blocks(fs, (struct ext2_inode *)inode,
> + 1);
> + if (err)
> + goto out;
> + }
> +
> + /* Allocate a block */
> + grp = ext2fs_group_of_ino(fs, ino);
> + goal = ext2fs_inode_table_loc(fs, grp);
> + err = ext2fs_alloc_block2(fs, goal, NULL, &blk);
> + if (err)
> + return err;
> + ext2fs_file_acl_block_set(fs, (struct ext2_inode *)inode, blk);
> +out2:
> + ext2fs_free_mem(&block_buf);
> +out:
> + return err;
> +}
> +
> +
> +static errcode_t write_xattrs_to_buffer(struct ext2_xattr_handle *handle,
> + struct ext2_xattr **pos,
> + void *entries_start,
> + unsigned int storage_size,
> + unsigned int value_offset_correction)
> +{
> + struct ext2_xattr *x = *pos;
> + struct ext2_ext_attr_entry *e = entries_start;
> + void *end = entries_start + storage_size;
> + char *shortname;
> + unsigned int entry_size, value_size;
> + int idx, ret;
> +
> + /* For all remaining x... */
> + for (; x < handle->attrs + handle->length; x++) {
> + if (!x->name)
> + continue;
> +
> + /* Calculate index and shortname position */
> + shortname = x->name;
> + ret = find_ea_index(x->name, &shortname, &idx);
> +
> + /* Calculate entry and value size */
> + entry_size = (sizeof(*e) + strlen(shortname) +
> + EXT2_EXT_ATTR_PAD - 1) &
> + ~(EXT2_EXT_ATTR_PAD - 1);
> + value_size = ((x->value_len + EXT2_EXT_ATTR_PAD - 1) /
> + EXT2_EXT_ATTR_PAD) * EXT2_EXT_ATTR_PAD;
> +
> + /*
> + * Would entry collide with value?
> + * Note that we must leave sufficient room for a (u32)0 to
> + * mark the end of the entries.
> + */
> + if ((void *)e + entry_size + sizeof(__u32) > end - value_size)
> + break;
> +
> + /* Fill out e appropriately */
> + e->e_name_len = strlen(shortname);
> + e->e_name_index = (ret ? idx : 0);
> + e->e_value_offs = end - value_size - (void *)entries_start +
> + value_offset_correction;
> + e->e_value_block = 0;
> + e->e_value_size = x->value_len;
> +
> + /* Store name and value */
> + end -= value_size;
> + memcpy((void *)e + sizeof(*e), shortname, e->e_name_len);
> + memcpy(end, x->value, e->e_value_size);
> +
> + e->e_hash = ext2fs_ext_attr_hash_entry(e, end);
> +
> + e = EXT2_EXT_ATTR_NEXT(e);
> + *(__u32 *)e = 0;
> + }
> + *pos = x;
> +
> + return 0;
> +}
> +
> +errcode_t ext2fs_xattrs_write(struct ext2_xattr_handle *handle)
> +{
> + struct ext2_xattr *x;
> + struct ext2_inode_large *inode;
> + void *start, *block_buf = NULL;
> + struct ext2_ext_attr_header *header;
> + __u32 ea_inode_magic;
> + blk64_t blk;
> + unsigned int storage_size;
> + unsigned int i, written;
> + errcode_t err;
> +
> + if (!EXT2_HAS_COMPAT_FEATURE(handle->fs->super,
> + EXT2_FEATURE_COMPAT_EXT_ATTR))
> + return 0;
> +
> + i = EXT2_INODE_SIZE(handle->fs->super);
> + if (i < sizeof(*inode))
> + i = sizeof(*inode);
> + err = ext2fs_get_memzero(i, &inode);
> + if (err)
> + return err;
> +
> + err = ext2fs_read_inode_full(handle->fs, handle->ino,
> + (struct ext2_inode *)inode,
> + EXT2_INODE_SIZE(handle->fs->super));
> + if (err)
> + goto out;
> +
> + x = handle->attrs;
> + /* Does the inode have size for EA? */
> + if (EXT2_INODE_SIZE(handle->fs->super) <= EXT2_GOOD_OLD_INODE_SIZE +
> + inode->i_extra_isize +
> + sizeof(__u32))
> + goto write_ea_block;
> +
> + /* Write the inode EA */
> + ea_inode_magic = EXT2_EXT_ATTR_MAGIC;
> + memcpy(((char *) inode) + EXT2_GOOD_OLD_INODE_SIZE +
> + inode->i_extra_isize, &ea_inode_magic, sizeof(__u32));
> + storage_size = EXT2_INODE_SIZE(handle->fs->super) -
> + EXT2_GOOD_OLD_INODE_SIZE - inode->i_extra_isize -
> + sizeof(__u32);
> + start = ((char *) inode) + EXT2_GOOD_OLD_INODE_SIZE +
> + inode->i_extra_isize + sizeof(__u32);
> +
> + err = write_xattrs_to_buffer(handle, &x, start, storage_size, 0);
> + if (err)
> + goto out;
> +
> + /* Are we done? */
> + if (x == handle->attrs + handle->length)
> + goto skip_ea_block;
> +
> +write_ea_block:
> + /* Write the EA block */
> + err = ext2fs_get_mem(handle->fs->blocksize, &block_buf);
> + if (err)
> + goto out;
> +
> + storage_size = handle->fs->blocksize -
> + sizeof(struct ext2_ext_attr_header);
> + start = block_buf + sizeof(struct ext2_ext_attr_header);
> +
> + err = write_xattrs_to_buffer(handle, &x, start, storage_size,
> + (void *)start - block_buf);
> + if (err)
> + goto out2;
> +
> + if (x < handle->attrs + handle->length) {
> + err = EXT2_ET_EA_NO_SPACE;
> + goto out2;
> + }
> +
> + if (block_buf) {
> + /* Write a header on the EA block */
> + header = block_buf;
> + header->h_magic = EXT2_EXT_ATTR_MAGIC;
> + header->h_refcount = 1;
> + header->h_blocks = 1;
> +
> + /* Get a new block for writing */
> + err = prep_ea_block_for_write(handle->fs, handle->ino, inode);
> + if (err)
> + goto out2;
> +
> + /* Finally, write the new EA block */
> + blk = ext2fs_file_acl_block(handle->fs,
> + (struct ext2_inode *)inode);
> + err = ext2fs_write_ext_attr3(handle->fs, blk, block_buf,
> + handle->ino);
> + if (err)
> + goto out2;
> + }
> +
> +skip_ea_block:
> + blk = ext2fs_file_acl_block(handle->fs, (struct ext2_inode *)inode);
> + if (!block_buf && blk) {
> + /* xattrs shrunk, free the block */
> + ext2fs_file_acl_block_set(handle->fs,
> + (struct ext2_inode *)inode, 0);
> + err = ext2fs_iblk_sub_blocks(handle->fs,
> + (struct ext2_inode *)inode, 1);
> + if (err)
> + goto out;
> + ext2fs_block_alloc_stats2(handle->fs, blk, -1);
> + }
> +
> + /* Write the inode */
> + err = ext2fs_write_inode_full(handle->fs, handle->ino,
> + (struct ext2_inode *)inode,
> + EXT2_INODE_SIZE(handle->fs->super));
> + if (err)
> + goto out2;
> +
> +out2:
> + ext2fs_free_mem(&block_buf);
> +out:
> + ext2fs_free_mem(&inode);
> + handle->dirty = 0;
> + return err;
> +}
> +
> +static errcode_t read_xattrs_from_buffer(struct ext2_xattr_handle *handle,
> + struct ext2_ext_attr_entry *entries,
> + unsigned int storage_size,
> + void *value_start)
> +{
> + struct ext2_xattr *x;
> + struct ext2_ext_attr_entry *entry;
> + const char *prefix;
> + void *ptr;
> + unsigned int remain, prefix_len;
> + errcode_t err;
> +
> + x = handle->attrs;
> + while (x->name)
> + x++;
> +
> + entry = entries;
> + while (!EXT2_EXT_IS_LAST_ENTRY(entry)) {
> + __u32 hash;
> +
> + /* header eats this space */
> + remain -= sizeof(struct ext2_ext_attr_entry);
> +
> + /* is attribute name valid? */
> + if (EXT2_EXT_ATTR_SIZE(entry->e_name_len) > remain)
> + return EXT2_ET_EA_BAD_NAME_LEN;
> +
> + /* attribute len eats this space */
> + remain -= EXT2_EXT_ATTR_SIZE(entry->e_name_len);
> +
> + /* check value size */
> + if (entry->e_value_size > remain)
> + return EXT2_ET_EA_BAD_VALUE_SIZE;
> +
> + /* e_value_block must be 0 in inode's ea */
> + if (entry->e_value_block != 0)
> + return EXT2_ET_BAD_EA_BLOCK_NUM;
> +
> + hash = ext2fs_ext_attr_hash_entry(entry, value_start +
> + entry->e_value_offs);
> +
> + /* e_hash may be 0 in older inode's ea */
> + if (entry->e_hash != 0 && entry->e_hash != hash)
> + return EXT2_ET_BAD_EA_HASH;
> +
> + remain -= entry->e_value_size;
> +
> + /* Allocate space for more attrs? */
> + if (x == handle->attrs + handle->length) {
> + err = ext2fs_xattrs_expand(handle, 4);
> + if (err)
> + return err;
> + x = handle->attrs + handle->length - 4;
> + }
> +
> + /* Extract name/value */
> + prefix = find_ea_prefix(entry->e_name_index);
> + prefix_len = (prefix ? strlen(prefix) : 0);
> + err = ext2fs_get_memzero(entry->e_name_len + prefix_len + 1,
> + &x->name);
> + if (err)
> + return err;
> + if (prefix)
> + memcpy(x->name, prefix, prefix_len);
> + if (entry->e_name_len)
> + memcpy(x->name + prefix_len,
> + (void *)entry + sizeof(*entry),
> + entry->e_name_len);
> +
> + err = ext2fs_get_mem(entry->e_value_size, &x->value);
> + if (err)
> + return err;
> + x->value_len = entry->e_value_size;
> + memcpy(x->value, value_start + entry->e_value_offs,
> + entry->e_value_size);
> + x++;
> + entry = EXT2_EXT_ATTR_NEXT(entry);
> + }
> +
> + return 0;
> +}
> +
> +errcode_t ext2fs_xattrs_read(struct ext2_xattr_handle *handle)
> +{
> + struct ext2_xattr *attrs = NULL, *x;
> + unsigned int attrs_len;
> + struct ext2_inode_large *inode;
> + struct ext2_ext_attr_header *header;
> + __u32 ea_inode_magic;
> + unsigned int storage_size;
> + void *start, *block_buf = NULL;
> + blk64_t blk;
> + int i;
> + errcode_t err;
> +
> + if (!EXT2_HAS_COMPAT_FEATURE(handle->fs->super,
> + EXT2_FEATURE_COMPAT_EXT_ATTR))
> + return 0;
> +
> + i = EXT2_INODE_SIZE(handle->fs->super);
> + if (i < sizeof(*inode))
> + i = sizeof(*inode);
> + err = ext2fs_get_memzero(i, &inode);
> + if (err)
> + return err;
> +
> + err = ext2fs_read_inode_full(handle->fs, handle->ino,
> + (struct ext2_inode *)inode,
> + EXT2_INODE_SIZE(handle->fs->super));
> + if (err)
> + goto out;
> +
> + /* Does the inode have size for EA? */
> + if (EXT2_INODE_SIZE(handle->fs->super) <= EXT2_GOOD_OLD_INODE_SIZE +
> + inode->i_extra_isize +
> + sizeof(__u32))
> + goto read_ea_block;
> +
> + /* Look for EA in the inode */
> + memcpy(&ea_inode_magic, ((char *) inode) + EXT2_GOOD_OLD_INODE_SIZE +
> + inode->i_extra_isize, sizeof(__u32));
> + if (ea_inode_magic == EXT2_EXT_ATTR_MAGIC) {
> + storage_size = EXT2_INODE_SIZE(handle->fs->super) -
> + EXT2_GOOD_OLD_INODE_SIZE - inode->i_extra_isize -
> + sizeof(__u32);
> + start = ((char *) inode) + EXT2_GOOD_OLD_INODE_SIZE +
> + inode->i_extra_isize + sizeof(__u32);
> +
> + err = read_xattrs_from_buffer(handle, start, storage_size,
> + start);
> + if (err)
> + goto out;
> + }
> +
> +read_ea_block:
> + /* Look for EA in a separate EA block */
> + blk = ext2fs_file_acl_block(handle->fs, (struct ext2_inode *)inode);
> + if (blk != 0) {
> + if ((blk < handle->fs->super->s_first_data_block) ||
> + (blk >= ext2fs_blocks_count(handle->fs->super))) {
> + err = EXT2_ET_BAD_EA_BLOCK_NUM;
> + goto out;
> + }
> +
> + err = ext2fs_get_mem(handle->fs->blocksize, &block_buf);
> + if (err)
> + goto out;
> +
> + err = ext2fs_read_ext_attr3(handle->fs, blk, block_buf,
> + handle->ino);
> + if (err)
> + goto out3;
> +
> + header = (struct ext2_ext_attr_header *) block_buf;
> + if (header->h_magic != EXT2_EXT_ATTR_MAGIC) {
> + err = EXT2_ET_BAD_EA_HEADER;
> + goto out3;
> + }
> +
> + if (header->h_blocks != 1) {
> + err = EXT2_ET_BAD_EA_HEADER;
> + goto out3;
> + }
> +
> + /* Read EAs */
> + storage_size = handle->fs->blocksize -
> + sizeof(struct ext2_ext_attr_header);
> + start = block_buf + sizeof(struct ext2_ext_attr_header);
> + err = read_xattrs_from_buffer(handle, start, storage_size,
> + block_buf);
> + if (err)
> + goto out3;
> +
> + ext2fs_free_mem(&block_buf);
> + }
> +
> + ext2fs_free_mem(&block_buf);
> + ext2fs_free_mem(&inode);
> + return 0;
> +
> +out3:
> + ext2fs_free_mem(&block_buf);
> +out:
> + ext2fs_free_mem(&inode);
> + return err;
> +}
> +
> +#define XATTR_ABORT 1
> +#define XATTR_CHANGED 2
> +errcode_t ext2fs_xattrs_iterate(struct ext2_xattr_handle *h,
> + int (*func)(char *name, char *value,
> + void *data),
> + void *data)
> +{
> + struct ext2_xattr *x;
> + errcode_t err;
> + int ret;
> +
> + for (x = h->attrs; x < h->attrs + h->length; x++) {
> + if (!x->name)
> + continue;
> +
> + ret = func(x->name, x->value, data);
> + if (ret & XATTR_CHANGED)
> + h->dirty = 1;
> + if (ret & XATTR_ABORT)
> + return 0;
> + }
> +
> + return 0;
> +}
> +
> +errcode_t ext2fs_xattr_get(struct ext2_xattr_handle *h, const char *key,
> + void **value, unsigned int *value_len)
> +{
> + struct ext2_xattr *x;
> + void *val;
> + errcode_t err;
> +
> + for (x = h->attrs; x < h->attrs + h->length; x++) {
> + if (!x->name)
> + continue;
> +
> + if (strcmp(x->name, key) == 0) {
> + err = ext2fs_get_mem(x->value_len, &val);
> + if (err)
> + return err;
> + memcpy(val, x->value, x->value_len);
> + *value = val;
> + *value_len = x->value_len;
> + return 0;
> + }
> + }
> +
> + return EXT2_ET_EA_KEY_NOT_FOUND;
> +}
> +
> +errcode_t ext2fs_xattr_set(struct ext2_xattr_handle *handle,
> + const char *key,
> + const void *value,
> + unsigned int value_len)
> +{
> + struct ext2_xattr *x, *last_empty;
> + char *new_value;
> + errcode_t err;
> +
> + last_empty = NULL;
> + for (x = handle->attrs; x < handle->attrs + handle->length; x++) {
> + if (!x->name) {
> + last_empty = x;
> + continue;
> + }
> +
> + /* Replace xattr */
> + if (strcmp(x->name, key) == 0) {
> + err = ext2fs_get_mem(value_len, &new_value);
> + if (err)
> + return err;
> + memcpy(new_value, value, value_len);
> + ext2fs_free_mem(&x->value);
> + x->value = new_value;
> + x->value_len = value_len;
> + handle->dirty = 1;
> + return 0;
> + }
> + }
> +
> + /* Add attr to empty slot */
> + if (last_empty) {
> + err = ext2fs_get_mem(strlen(key) + 1, &last_empty->name);
> + if (err)
> + return err;
> + strcpy(last_empty->name, key);
> +
> + err = ext2fs_get_mem(value_len, &last_empty->value);
> + if (err)
> + return err;
> + memcpy(last_empty->value, value, value_len);
> + last_empty->value_len = value_len;
> + handle->dirty = 1;
> + return 0;
> + }
> +
> + /* Expand array, append slot */
> + err = ext2fs_xattrs_expand(handle, 4);
> + if (err)
> + return err;
> +
> + x = handle->attrs + handle->length - 4;
> + err = ext2fs_get_mem(strlen(key) + 1, &x->name);
> + if (err)
> + return err;
> + strcpy(x->name, key);
> +
> + err = ext2fs_get_mem(value_len, &x->value);
> + if (err)
> + return err;
> + memcpy(x->value, value, value_len);
> + x->value_len = value_len;
> + handle->dirty = 1;
> + return 0;
> +}
> +
> +errcode_t ext2fs_xattr_remove(struct ext2_xattr_handle *handle,
> + const char *key)
> +{
> + struct ext2_xattr *x;
> + errcode_t err;
> +
> + for (x = handle->attrs; x < handle->attrs + handle->length; x++) {
> + if (!x->name)
> + continue;
> +
> + if (strcmp(x->name, key) == 0) {
> + ext2fs_free_mem(&x->name);
> + ext2fs_free_mem(&x->value);
> + x->value_len = 0;
> + handle->dirty = 1;
> + return 0;
> + }
> + }
> +
> + return EXT2_ET_EA_KEY_NOT_FOUND;
> +}
> +
> +errcode_t ext2fs_xattrs_open(ext2_filsys fs, ext2_ino_t ino,
> + struct ext2_xattr_handle **handle)
> +{
> + struct ext2_xattr_handle *h;
> + errcode_t err;
> +
> + err = ext2fs_get_memzero(sizeof(*h), &h);
> + if (err)
> + return err;
> +
> + h->length = 4;
> + err = ext2fs_get_arrayzero(h->length, sizeof(struct ext2_xattr),
> + &h->attrs);
> + if (err) {
> + ext2fs_free_mem(&h);
> + return err;
> + }
> + h->ino = ino;
> + h->fs = fs;
> + *handle = h;
> + return 0;
> +}
> +
> +errcode_t ext2fs_xattrs_close(struct ext2_xattr_handle **handle)
> +{
> + unsigned int i;
> + struct ext2_xattr_handle *h = *handle;
> + struct ext2_xattr *a = h->attrs;
> + errcode_t err;
> +
> + if (h->dirty) {
> + err = ext2fs_xattrs_write(h);
> + if (err)
> + return err;
> + }
> +
> + for (i = 0; i < h->length; i++) {
> + if (a[i].name)
> + ext2fs_free_mem(&a[i].name);
> + if (a[i].value)
> + ext2fs_free_mem(&a[i].value);
> + }
> +
> + ext2fs_free_mem(&h->attrs);
> + ext2fs_free_mem(handle);
> + return 0;
> +}
> --
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