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Date: Wed, 27 Nov 2013 10:52:32 +0800
From: Zheng Liu <gnehzuil.liu@...il.com>
To: "Darrick J. Wong" <darrick.wong@...cle.com>
Cc: tytso@....edu, linux-ext4@...r.kernel.org
Subject: Re: [PATCH 23/25] libext2fs: support modifying arbitrary extended
attributes
On Tue, Nov 26, 2013 at 11:55:47AM -0800, Darrick J. Wong wrote:
> On Tue, Nov 26, 2013 at 03:21:16PM +0800, Zheng Liu wrote:
> > On Thu, Oct 17, 2013 at 09:51:34PM -0700, Darrick J. Wong wrote:
> > > 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.
> > >
> > > v2: Put the header declarations in the correct part of ext2fs.h,
> > > provide a function to release an EA block from an inode, and check
> > > i_extra_isize to make sure we actually have space for in-inode EAs.
> >
> > Is this the latest version? I am working on inline data patch set for
> > e2fsprogs, and I want to use these API to manipulate the EA. So that
> > would be great if you could point out which one is the latest version.
> > Thanks in advance. Otherwise some nits below.
>
> Oh! I was just about to start working on pulling your patches into my monster
> patchset. :)
Wow! Sorry for my late. If you just begin to work on inline data
patchset. Would you mind sending your latest monster patchset without
my inline data patchset first? That gives me a chance to take a closer
look at them. In general, I will send my patch set asap.
>
> I changed the extended attribute API a little bit -- the function pointer to
> ext2fs_xattrs_iterate() takes a value length; lengths are now specified in
> size_t; and the ext2fs_xattrs_count() call is new. I removed
> ext2fs_xattrs_expand() since it's an internal call.
>
> This is the current set of APIs:
>
> 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,
> size_t value_len, void *data),
> void *data);
> errcode_t ext2fs_xattr_get(struct ext2_xattr_handle *h, const char *key,
> void **value, size_t *value_len);
> errcode_t ext2fs_xattr_set(struct ext2_xattr_handle *handle,
> const char *key,
> const void *value,
> size_t 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);
> size_t ext2fs_xattrs_count(struct ext2_xattr_handle *handle);
That would be great if you could send a latest patch to me, and it seems
that I don't need to adjust my patch too much. :)
>
> I was planning a couple of modifications to support inline_data -- since we can
> rewrite the inode-ea and ea-block arbitrarily, ext2fs_xattrs_write() ought to
> ensure that the inlinedata EA gets written into i_blocks and the beginning of
> the inode-ea area.
It makes no sense to me because we should ensure a function just does
one thing. Hence, ext2fs_xattrs_write() just needs to write data into
ea area, and it doesn't need to care about the content of these data.
>
> Should the attributes be sorted before writing? I was thinking that the
> desirable(?) order might be inline_data, security attributes, "everything
> else", then user attributes? Or we could simply maintain FCFS order as is done
> now.
At the front of fs/ext4/xattr.c file:
* The header is followed by multiple entry descriptors. In disk blocks, the
* entry descriptors are kept sorted. In inodes, they are unsorted. The
* attribute values are aligned to the end of the block in no specific order.
If I understand correctly, we just need to sort the entries.
>
> The other change was to ext2fs_xattr_set() to return
> EXT2_ET_INLINE_DATA_NO_SPACE if it figures out that there's not enough space in
> i_blocks + inode-ea to fit the inline data.
As I said above, ext2fs_xattr_set() don't need to handle i_blocks. But
I think it quite needs to add a parameter to indicate whether we want to
allocate a block to store these ea data.
Thanks,
- Zheng
>
> > >
> > > 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 | 761 +++++++++++++++++++++++++++++++++++++++++++++
> > > 3 files changed, 807 insertions(+)
> > >
> > >
> > > diff --git a/lib/ext2fs/ext2_err.et.in b/lib/ext2fs/ext2_err.et.in
> > > index 9cc1bd1..b819a90 100644
> > > --- a/lib/ext2fs/ext2_err.et.in
> > > +++ b/lib/ext2fs/ext2_err.et.in
> > > @@ -482,4 +482,22 @@ ec EXT2_ET_BLOCK_BITMAP_CSUM_INVALID,
> > > ec EXT2_ET_INLINE_DATA_CANT_ITERATE,
> > > "Cannot block iterate on an inode containing inline data"
> > >
> > > +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 5247922..93adae8 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)
> > > @@ -1151,6 +1158,27 @@ 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..2a1e5e7 100644
> > > --- a/lib/ext2fs/ext_attr.c
> > > +++ b/lib/ext2fs/ext_attr.c
> > > @@ -186,3 +186,764 @@ 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."},
> >
> > It seems that we also have a _RICHACL name here.
> >
> > > + {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++)
> >
> > Coding style problem:
> > for (e = ea_names; e->name; e++) {
> > ...
> > }
>
> Ok I'll change it.
>
> --D
>
> > Thanks,
> > - Zheng
> >
> > > + 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;
> > > + struct ext2_inode_large i;
> > > +
> > > + /* Read inode? */
> > > + if (inode == NULL) {
> > > + err = ext2fs_read_inode_full(fs, ino, (struct ext2_inode *)&i,
> > > + sizeof(struct ext2_inode_large));
> > > + if (err)
> > > + return err;
> > > + inode = &i;
> > > + }
> > > +
> > > + /* 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);
> > > +
> > > + /* Write inode? */
> > > + if (inode == &i) {
> > > + err = ext2fs_write_inode_full(fs, ino, (struct ext2_inode *)&i,
> > > + sizeof(struct ext2_inode_large));
> > > + if (err)
> > > + goto out2;
> > > + }
> > > +
> > > +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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> > > the body of a message to majordomo@...r.kernel.org
> > > More majordomo info at http://vger.kernel.org/majordomo-info.html
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