source: trunk/server/source4/ntvfs/posix/xattr_tdb.c

/* 
   Unix SMB/CIFS implementation.

   POSIX NTVFS backend - xattr support using a tdb

   Copyright (C) Andrew Tridgell 2004

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "includes.h"
#include "lib/util/tdb_wrap.h"
#include <tdb.h>
#include "vfs_posix.h"

#define XATTR_LIST_ATTR ".xattr_list"

/*
  we need to maintain a list of attributes on each file, so that unlink
  can automatically clean them up
*/
static NTSTATUS xattr_tdb_add_list(struct tdb_wrap *ea_tdb, TALLOC_CTX *ctx, const char *attr_name,
                                   const char *fname, int fd)
{
        DATA_BLOB blob;
        TALLOC_CTX *mem_ctx;
        const char *s;
        NTSTATUS status;
        size_t len;

        if (strcmp(attr_name, XATTR_LIST_ATTR) == 0) {
                return NT_STATUS_OK;
        }

        mem_ctx = talloc_new(ctx);

        status = pull_xattr_blob_tdb_raw(ea_tdb, mem_ctx, XATTR_LIST_ATTR,
                                     fname, fd, 100, &blob);
        if (!NT_STATUS_IS_OK(status)) {
                blob = data_blob(NULL, 0);
        }

        for (s=(const char *)blob.data; s < (const char *)(blob.data+blob.length); s += strlen(s) + 1) {
                if (strcmp(attr_name, s) == 0) {
                        talloc_free(mem_ctx);
                        return NT_STATUS_OK;
                }
        }

        len = strlen(attr_name) + 1;

        blob.data = talloc_realloc(mem_ctx, blob.data, uint8_t, blob.length + len);
        if (blob.data == NULL) {
                talloc_free(mem_ctx);
                return NT_STATUS_NO_MEMORY;             
        }
        memcpy(blob.data + blob.length, attr_name, len);
        blob.length += len;

        status = push_xattr_blob_tdb_raw(ea_tdb,ctx, XATTR_LIST_ATTR, fname, fd, &blob);
        talloc_free(mem_ctx);

        return status;
}

/*
  form a key for using in the ea_tdb
*/
static NTSTATUS get_ea_tdb_key(TALLOC_CTX *mem_ctx,
                              const char *attr_name,
                              const char *fname, int fd, 
                              TDB_DATA *key)
{
        struct stat st;
        size_t len = strlen(attr_name);

        if (fd == -1) {
                if (stat(fname, &st) == -1) {
                        return NT_STATUS_NOT_FOUND;
                }
        } else {
                if (fstat(fd, &st) == -1) {
                        return NT_STATUS_NOT_FOUND;
                }
        }

        key->dptr = talloc_array(mem_ctx, uint8_t, 16 + len);
        if (key->dptr == NULL) {
                return NT_STATUS_NO_MEMORY;
        }
        key->dsize = 16 + len;

        SBVAL(key->dptr, 0, st.st_dev);
        SBVAL(key->dptr, 8, st.st_ino);
        memcpy(key->dptr+16, attr_name, len);
        
        return NT_STATUS_OK;
}



/*
  pull a xattr as a blob, using the ea_tdb_context tdb
*/
NTSTATUS pull_xattr_blob_tdb_raw(struct tdb_wrap *ea_tdb,
                             TALLOC_CTX *mem_ctx,
                             const char *attr_name,
                             const char *fname,
                             int fd,
                             size_t estimated_size,
                             DATA_BLOB *blob)
{
        TDB_DATA tkey, tdata;
        NTSTATUS status;

        status = get_ea_tdb_key(mem_ctx, attr_name, fname, fd, &tkey);
        if (!NT_STATUS_IS_OK(status)) {
                return status;
        }

        tdata = tdb_fetch(ea_tdb->tdb, tkey);
        if (tdata.dptr == NULL) {
                return NT_STATUS_NOT_FOUND;
        }

        *blob = data_blob_talloc(mem_ctx, tdata.dptr, tdata.dsize);
        free(tdata.dptr);
        if (blob->data == NULL) {
                return NT_STATUS_NO_MEMORY;
        }

        return NT_STATUS_OK;    
}

NTSTATUS pull_xattr_blob_tdb(struct pvfs_state *pvfs,
                             TALLOC_CTX *mem_ctx,
                             const char *attr_name,
                             const char *fname,
                             int fd,
                             size_t estimated_size,
                             DATA_BLOB *blob)
{
        return pull_xattr_blob_tdb_raw(pvfs->ea_db,mem_ctx,attr_name,fname,fd,estimated_size,blob);
}

/*
  push a xattr as a blob, using ea_tdb
*/
NTSTATUS push_xattr_blob_tdb_raw(struct tdb_wrap *ea_tdb,
                             TALLOC_CTX *mem_ctx,
                             const char *attr_name,
                             const char *fname,
                             int fd,
                             const DATA_BLOB *blob)
{
        TDB_DATA tkey, tdata;
        NTSTATUS status;

        status = get_ea_tdb_key(mem_ctx, attr_name, fname, fd, &tkey);
        if (!NT_STATUS_IS_OK(status)) {
                return status;
        }
        
        tdata.dptr = blob->data;
        tdata.dsize = blob->length;

        if (tdb_chainlock(ea_tdb->tdb, tkey) != 0) {
                talloc_free(tkey.dptr);
                return NT_STATUS_INTERNAL_DB_CORRUPTION;
        }

        status = xattr_tdb_add_list(ea_tdb,mem_ctx, attr_name, fname, fd);
        if (!NT_STATUS_IS_OK(status)) {
                goto done;
        }

        if (tdb_store(ea_tdb->tdb, tkey, tdata, TDB_REPLACE) == -1) {
                status = NT_STATUS_INTERNAL_DB_CORRUPTION;
        }

done:
        tdb_chainunlock(ea_tdb->tdb, tkey);
        talloc_free(tkey.dptr);
        return status;  
}
NTSTATUS push_xattr_blob_tdb(struct pvfs_state *pvfs,
                             const char *attr_name,
                             const char *fname,
                             int fd,
                             const DATA_BLOB *blob)
{
        return push_xattr_blob_tdb_raw(pvfs->ea_db,pvfs,attr_name,fname,fd,blob);
}


/*
  delete a xattr
*/
NTSTATUS delete_xattr_tdb(struct pvfs_state *pvfs, const char *attr_name, 
                          const char *fname, int fd)
{
        TDB_DATA tkey;
        NTSTATUS status;

        status = get_ea_tdb_key(NULL, attr_name, fname, fd, &tkey);
        if (!NT_STATUS_IS_OK(status)) {
                return status;
        }
        
        if (tdb_delete(pvfs->ea_db->tdb, tkey) == -1) {
                talloc_free(tkey.dptr);
                return NT_STATUS_INTERNAL_DB_CORRUPTION;
        }

        talloc_free(tkey.dptr);
        return NT_STATUS_OK;    
}



/*
  delete all xattrs for a file
*/
NTSTATUS unlink_xattr_tdb(struct pvfs_state *pvfs, const char *fname)
{
        TALLOC_CTX *mem_ctx = talloc_new(pvfs);
        DATA_BLOB blob;
        const char *s;
        NTSTATUS status;

        status = pull_xattr_blob_tdb(pvfs, mem_ctx, XATTR_LIST_ATTR,
                                     fname, -1, 100, &blob);
        if (!NT_STATUS_IS_OK(status)) {
                talloc_free(mem_ctx);
                return NT_STATUS_OK;
        }

        for (s=(const char *)blob.data; s < (const char *)(blob.data+blob.length); s += strlen(s) + 1) {
                delete_xattr_tdb(pvfs, s, fname, -1);
        }

        status = delete_xattr_tdb(pvfs, XATTR_LIST_ATTR, fname, -1);
        talloc_free(mem_ctx);
        return status;
}