diff options
Diffstat (limited to 'source3/modules/vfs_streams_depot.c')
| -rw-r--r-- | source3/modules/vfs_streams_depot.c | 641 |
1 files changed, 641 insertions, 0 deletions
diff --git a/source3/modules/vfs_streams_depot.c b/source3/modules/vfs_streams_depot.c new file mode 100644 index 0000000000..fa85ea4a57 --- /dev/null +++ b/source3/modules/vfs_streams_depot.c @@ -0,0 +1,641 @@ +/* + * Store streams in a separate subdirectory + * + * Copyright (C) Volker Lendecke, 2007 + * + * 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" + +#undef DBGC_CLASS +#define DBGC_CLASS DBGC_VFS + +/* + * Excerpt from a mail from tridge: + * + * Volker, what I'm thinking of is this: + * /mount-point/.streams/XX/YY/aaaa.bbbb/namedstream1 + * /mount-point/.streams/XX/YY/aaaa.bbbb/namedstream2 + * + * where XX/YY is a 2 level hash based on the fsid/inode. "aaaa.bbbb" + * is the fsid/inode. "namedstreamX" is a file named after the stream + * name. + */ + +static uint32_t hash_fn(DATA_BLOB key) +{ + uint32_t value; /* Used to compute the hash value. */ + uint32_t i; /* Used to cycle through random values. */ + + /* Set the initial value from the key size. */ + for (value = 0x238F13AF * key.length, i=0; i < key.length; i++) + value = (value + (key.data[i] << (i*5 % 24))); + + return (1103515243 * value + 12345); +} + +/* + * With the hashing scheme based on the inode we need to protect against + * streams showing up on files with re-used inodes. This can happen if we + * create a stream directory from within Samba, and a local process or NFS + * client deletes the file without deleting the streams directory. When the + * inode is re-used and the stream directory is still around, the streams in + * there would be show up as belonging to the new file. + * + * There are several workarounds for this, probably the easiest one is on + * systems which have a true birthtime stat element: When the file has a later + * birthtime than the streams directory, then we have to recreate the + * directory. + * + * The other workaround is to somehow mark the file as generated by Samba with + * something that a NFS client would not do. The closest one is a special + * xattr value being set. On systems which do not support xattrs, it might be + * an option to put in a special ACL entry for a non-existing group. + */ + +#define SAMBA_XATTR_MARKER "user.SAMBA_STREAMS" + +static bool file_is_valid(vfs_handle_struct *handle, const char *path) +{ + char buf; + + DEBUG(10, ("file_is_valid (%s) called\n", path)); + + if (SMB_VFS_NEXT_GETXATTR(handle, path, SAMBA_XATTR_MARKER, + &buf, sizeof(buf)) != sizeof(buf)) { + DEBUG(10, ("GETXATTR failed: %s\n", strerror(errno))); + return false; + } + + if (buf != '1') { + DEBUG(10, ("got wrong buffer content: '%c'\n", buf)); + return false; + } + + return true; +} + +static bool mark_file_valid(vfs_handle_struct *handle, const char *path) +{ + char buf = '1'; + int ret; + + DEBUG(10, ("marking file %s as valid\n", path)); + + ret = SMB_VFS_NEXT_SETXATTR(handle, path, SAMBA_XATTR_MARKER, + &buf, sizeof(buf), 0); + + if (ret == -1) { + DEBUG(10, ("SETXATTR failed: %s\n", strerror(errno))); + return false; + } + + return true; +} + +static char *stream_dir(vfs_handle_struct *handle, const char *base_path, + const SMB_STRUCT_STAT *base_sbuf, bool create_it) +{ + uint32_t hash; + char *result = NULL; + SMB_STRUCT_STAT sbuf; + uint8_t first, second; + char *tmp; + char *id_hex; + struct file_id id; + uint8 id_buf[16]; + + const char *rootdir = lp_parm_const_string( + SNUM(handle->conn), "streams", "directory", + handle->conn->connectpath); + + if (base_sbuf == NULL) { + if (SMB_VFS_NEXT_STAT(handle, base_path, &sbuf) == -1) { + /* + * base file is not there + */ + goto fail; + } + base_sbuf = &sbuf; + } + + id = SMB_VFS_FILE_ID_CREATE(handle->conn, base_sbuf->st_dev, + base_sbuf->st_ino); + + push_file_id_16((char *)id_buf, &id); + + hash = hash_fn(data_blob_const(id_buf, sizeof(id_buf))); + + first = hash & 0xff; + second = (hash >> 8) & 0xff; + + id_hex = hex_encode(talloc_tos(), id_buf, sizeof(id_buf)); + + if (id_hex == NULL) { + errno = ENOMEM; + goto fail; + } + + result = talloc_asprintf(talloc_tos(), "%s/%2.2X/%2.2X/%s", rootdir, + first, second, id_hex); + + TALLOC_FREE(id_hex); + + if (result == NULL) { + errno = ENOMEM; + return NULL; + } + + if (SMB_VFS_NEXT_STAT(handle, result, &sbuf) == 0) { + char *newname; + + if (!S_ISDIR(sbuf.st_mode)) { + errno = EINVAL; + goto fail; + } + + if (file_is_valid(handle, base_path)) { + return result; + } + + /* + * Someone has recreated a file under an existing inode + * without deleting the streams directory. For now, just move + * it away. + */ + + again: + newname = talloc_asprintf(talloc_tos(), "lost-%lu", random()); + if (newname == NULL) { + errno = ENOMEM; + goto fail; + } + + if (SMB_VFS_NEXT_RENAME(handle, result, newname) == -1) { + if ((errno == EEXIST) || (errno == ENOTEMPTY)) { + TALLOC_FREE(newname); + goto again; + } + goto fail; + } + + TALLOC_FREE(newname); + } + + if (!create_it) { + errno = ENOENT; + goto fail; + } + + if ((SMB_VFS_NEXT_MKDIR(handle, rootdir, 0755) != 0) + && (errno != EEXIST)) { + goto fail; + } + + tmp = talloc_asprintf(result, "%s/%2.2X", rootdir, first); + if (tmp == NULL) { + errno = ENOMEM; + goto fail; + } + + if ((SMB_VFS_NEXT_MKDIR(handle, tmp, 0755) != 0) + && (errno != EEXIST)) { + goto fail; + } + + TALLOC_FREE(tmp); + + tmp = talloc_asprintf(result, "%s/%2.2X/%2.2X", rootdir, first, + second); + if (tmp == NULL) { + errno = ENOMEM; + goto fail; + } + + if ((SMB_VFS_NEXT_MKDIR(handle, tmp, 0755) != 0) + && (errno != EEXIST)) { + goto fail; + } + + TALLOC_FREE(tmp); + + if ((SMB_VFS_NEXT_MKDIR(handle, result, 0755) != 0) + && (errno != EEXIST)) { + goto fail; + } + + if (!mark_file_valid(handle, base_path)) { + goto fail; + } + + return result; + + fail: + TALLOC_FREE(result); + return NULL; +} + +static char *stream_name(vfs_handle_struct *handle, const char *fname, + bool create_dir) +{ + char *base = NULL; + char *sname = NULL; + char *id_hex = NULL; + char *dirname, *stream_fname; + + if (!NT_STATUS_IS_OK(split_ntfs_stream_name(talloc_tos(), fname, + &base, &sname))) { + DEBUG(10, ("split_ntfs_stream_name failed\n")); + errno = ENOMEM; + goto fail; + } + + dirname = stream_dir(handle, base, NULL, create_dir); + + if (dirname == NULL) { + goto fail; + } + + stream_fname = talloc_asprintf(talloc_tos(), "%s/:%s", dirname, sname); + + if (stream_fname == NULL) { + errno = ENOMEM; + goto fail; + } + + DEBUG(10, ("stream filename = %s\n", stream_fname)); + + TALLOC_FREE(base); + TALLOC_FREE(sname); + TALLOC_FREE(id_hex); + + return stream_fname; + + fail: + DEBUG(5, ("stream_name failed: %s\n", strerror(errno))); + TALLOC_FREE(base); + TALLOC_FREE(sname); + TALLOC_FREE(id_hex); + return NULL; +} + +static NTSTATUS walk_streams(vfs_handle_struct *handle, + const char *fname, + const SMB_STRUCT_STAT *sbuf, + char **pdirname, + bool (*fn)(const char *dirname, + const char *dirent, + void *private_data), + void *private_data) +{ + char *dirname; + SMB_STRUCT_DIR *dirhandle = NULL; + char *dirent; + + dirname = stream_dir(handle, fname, sbuf, false); + + if (dirname == NULL) { + if (errno == ENOENT) { + /* + * no stream around + */ + return NT_STATUS_OK; + } + return map_nt_error_from_unix(errno); + } + + DEBUG(10, ("walk_streams: dirname=%s\n", dirname)); + + dirhandle = SMB_VFS_NEXT_OPENDIR(handle, dirname, NULL, 0); + + if (dirhandle == NULL) { + TALLOC_FREE(dirname); + return map_nt_error_from_unix(errno); + } + + while ((dirent = vfs_readdirname(handle->conn, dirhandle)) != NULL) { + + if (ISDOT(dirent) || ISDOTDOT(dirent)) { + continue; + } + + DEBUG(10, ("walk_streams: dirent=%s\n", dirent)); + + if (!fn(dirname, dirent, private_data)) { + break; + } + } + + SMB_VFS_NEXT_CLOSEDIR(handle, dirhandle); + + if (pdirname != NULL) { + *pdirname = dirname; + } + else { + TALLOC_FREE(dirname); + } + + return NT_STATUS_OK; +} + +static int streams_depot_stat(vfs_handle_struct *handle, const char *fname, + SMB_STRUCT_STAT *sbuf) +{ + char *stream_fname; + int ret = -1; + + DEBUG(10, ("streams_depot_stat called for [%s]\n", fname)); + + if (!is_ntfs_stream_name(fname)) { + return SMB_VFS_NEXT_STAT(handle, fname, sbuf); + } + + stream_fname = stream_name(handle, fname, false); + if (stream_fname == NULL) { + goto done; + } + + ret = SMB_VFS_NEXT_STAT(handle, stream_fname, sbuf); + + done: + TALLOC_FREE(stream_fname); + return ret; +} + +static int streams_depot_lstat(vfs_handle_struct *handle, const char *fname, + SMB_STRUCT_STAT *sbuf) +{ + char *stream_fname; + int ret = -1; + + if (!is_ntfs_stream_name(fname)) { + return SMB_VFS_NEXT_LSTAT(handle, fname, sbuf); + } + + stream_fname = stream_name(handle, fname, false); + if (stream_fname == NULL) { + goto done; + } + + ret = SMB_VFS_NEXT_LSTAT(handle, stream_fname, sbuf); + + done: + TALLOC_FREE(stream_fname); + return ret; +} + +static int streams_depot_open(vfs_handle_struct *handle, const char *fname, + files_struct *fsp, int flags, mode_t mode) +{ + TALLOC_CTX *frame; + char *base = NULL; + SMB_STRUCT_STAT base_sbuf; + char *stream_fname; + int ret = -1; + + if (!is_ntfs_stream_name(fname)) { + return SMB_VFS_NEXT_OPEN(handle, fname, fsp, flags, mode); + } + + frame = talloc_stackframe(); + + if (!NT_STATUS_IS_OK(split_ntfs_stream_name(talloc_tos(), fname, + &base, NULL))) { + errno = ENOMEM; + goto done; + } + + ret = SMB_VFS_NEXT_STAT(handle, base, &base_sbuf); + + if (ret == -1) { + goto done; + } + + TALLOC_FREE(base); + + stream_fname = stream_name(handle, fname, true); + if (stream_fname == NULL) { + goto done; + } + + ret = SMB_VFS_NEXT_OPEN(handle, stream_fname, fsp, flags, mode); + + done: + TALLOC_FREE(frame); + return ret; +} + +static int streams_depot_unlink(vfs_handle_struct *handle, const char *fname) +{ + int ret = -1; + SMB_STRUCT_STAT sbuf; + + DEBUG(10, ("streams_depot_unlink called for %s\n", fname)); + + if (is_ntfs_stream_name(fname)) { + char *stream_fname; + + stream_fname = stream_name(handle, fname, false); + if (stream_fname == NULL) { + return -1; + } + + ret = SMB_VFS_NEXT_UNLINK(handle, stream_fname); + + TALLOC_FREE(stream_fname); + return ret; + } + + /* + * We potentially need to delete the per-inode streams directory + */ + + if (SMB_VFS_NEXT_STAT(handle, fname, &sbuf) == -1) { + return -1; + } + + if (sbuf.st_nlink == 1) { + char *dirname = stream_dir(handle, fname, &sbuf, false); + + if (dirname != NULL) { + SMB_VFS_NEXT_RMDIR(handle, dirname); + } + TALLOC_FREE(dirname); + } + + return SMB_VFS_NEXT_UNLINK(handle, fname); +} + +static bool add_one_stream(TALLOC_CTX *mem_ctx, unsigned int *num_streams, + struct stream_struct **streams, + const char *name, SMB_OFF_T size, + SMB_OFF_T alloc_size) +{ + struct stream_struct *tmp; + + tmp = TALLOC_REALLOC_ARRAY(mem_ctx, *streams, struct stream_struct, + (*num_streams)+1); + if (tmp == NULL) { + return false; + } + + tmp[*num_streams].name = talloc_strdup(tmp, name); + if (tmp[*num_streams].name == NULL) { + return false; + } + + tmp[*num_streams].size = size; + tmp[*num_streams].alloc_size = alloc_size; + + *streams = tmp; + *num_streams += 1; + return true; +} + +struct streaminfo_state { + TALLOC_CTX *mem_ctx; + vfs_handle_struct *handle; + unsigned int num_streams; + struct stream_struct *streams; + NTSTATUS status; +}; + +static bool collect_one_stream(const char *dirname, + const char *dirent, + void *private_data) +{ + struct streaminfo_state *state = + (struct streaminfo_state *)private_data; + char *full_sname; + SMB_STRUCT_STAT sbuf; + + if (asprintf(&full_sname, "%s/%s", dirname, dirent) == -1) { + state->status = NT_STATUS_NO_MEMORY; + return false; + } + if (SMB_VFS_NEXT_STAT(state->handle, full_sname, &sbuf) == -1) { + DEBUG(10, ("Could not stat %s: %s\n", full_sname, + strerror(errno))); + SAFE_FREE(full_sname); + return true; + } + + SAFE_FREE(full_sname); + + if (!add_one_stream(state->mem_ctx, + &state->num_streams, &state->streams, + dirent, sbuf.st_size, + get_allocation_size( + state->handle->conn, NULL, &sbuf))) { + state->status = NT_STATUS_NO_MEMORY; + return false; + } + + return true; +} + +static NTSTATUS streams_depot_streaminfo(vfs_handle_struct *handle, + struct files_struct *fsp, + const char *fname, + TALLOC_CTX *mem_ctx, + unsigned int *pnum_streams, + struct stream_struct **pstreams) +{ + SMB_STRUCT_STAT sbuf; + int ret; + NTSTATUS status; + struct streaminfo_state state; + + if ((fsp != NULL) && (fsp->fh->fd != -1)) { + if (is_ntfs_stream_name(fsp->fsp_name)) { + return NT_STATUS_INVALID_PARAMETER; + } + ret = SMB_VFS_NEXT_FSTAT(handle, fsp, &sbuf); + } + else { + if (is_ntfs_stream_name(fname)) { + return NT_STATUS_INVALID_PARAMETER; + } + ret = SMB_VFS_NEXT_STAT(handle, fname, &sbuf); + } + + if (ret == -1) { + return map_nt_error_from_unix(errno); + } + + state.streams = NULL; + state.num_streams = 0; + + if (!S_ISDIR(sbuf.st_mode)) { + if (!add_one_stream(mem_ctx, + &state.num_streams, &state.streams, + "::$DATA", sbuf.st_size, + get_allocation_size(handle->conn, fsp, + &sbuf))) { + return NT_STATUS_NO_MEMORY; + } + } + + state.mem_ctx = mem_ctx; + state.handle = handle; + state.status = NT_STATUS_OK; + + status = walk_streams(handle, fname, &sbuf, NULL, collect_one_stream, + &state); + + if (!NT_STATUS_IS_OK(status)) { + TALLOC_FREE(state.streams); + return status; + } + + if (!NT_STATUS_IS_OK(state.status)) { + TALLOC_FREE(state.streams); + return state.status; + } + + *pnum_streams = state.num_streams; + *pstreams = state.streams; + return NT_STATUS_OK; +} + +static uint32_t streams_depot_fs_capabilities(struct vfs_handle_struct *handle) +{ + return SMB_VFS_NEXT_FS_CAPABILITIES(handle) | FILE_NAMED_STREAMS; +} + +/* VFS operations structure */ + +static vfs_op_tuple streams_depot_ops[] = { + {SMB_VFS_OP(streams_depot_fs_capabilities), SMB_VFS_OP_FS_CAPABILITIES, + SMB_VFS_LAYER_TRANSPARENT}, + {SMB_VFS_OP(streams_depot_open), SMB_VFS_OP_OPEN, + SMB_VFS_LAYER_TRANSPARENT}, + {SMB_VFS_OP(streams_depot_stat), SMB_VFS_OP_STAT, + SMB_VFS_LAYER_TRANSPARENT}, + {SMB_VFS_OP(streams_depot_lstat), SMB_VFS_OP_LSTAT, + SMB_VFS_LAYER_TRANSPARENT}, + {SMB_VFS_OP(streams_depot_unlink), SMB_VFS_OP_UNLINK, + SMB_VFS_LAYER_TRANSPARENT}, + {SMB_VFS_OP(streams_depot_streaminfo), SMB_VFS_OP_STREAMINFO, + SMB_VFS_LAYER_OPAQUE}, + {SMB_VFS_OP(NULL), SMB_VFS_OP_NOOP, SMB_VFS_LAYER_NOOP} +}; + +NTSTATUS vfs_streams_depot_init(void); +NTSTATUS vfs_streams_depot_init(void) +{ + return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "streams_depot", + streams_depot_ops); +} |