struct wim_lookup_table_entry;
struct read_stream_list_callbacks;
+struct apply_operations;
+struct wim_dentry;
struct apply_ctx {
/* The WIMStruct from which files are being extracted from the currently
struct wim_features supported_features;
/* The members below should not be used outside of extract.c */
+ const struct apply_operations *apply_ops;
u64 next_progress;
unsigned long invalid_sequence;
unsigned long num_streams_remaining;
extract_stream_list(struct apply_ctx *ctx,
const struct read_stream_list_callbacks *cbs);
+/*
+ * Represents an extraction backend.
+ */
struct apply_operations {
+
+ /* Name of the extraction backend. */
const char *name;
+
+ /*
+ * Query the features supported by the extraction backend.
+ *
+ * @target
+ * The target string that was provided by the user. (Often a
+ * directory, but extraction backends are free to interpret this
+ * differently.)
+ *
+ * @supported_features
+ * A structure, each of whose members represents a feature that may
+ * be supported by the extraction backend. For each feature that
+ * the extraction backend supports, this routine must set the
+ * corresponding member to a nonzero value.
+ *
+ * Return 0 if successful; otherwise a positive wimlib error code.
+ */
int (*get_supported_features)(const tchar *target,
struct wim_features *supported_features);
+ /*
+ * Main extraction routine.
+ *
+ * The extraction backend is provided a list of dentries that have been
+ * prepared for extraction. It is free to extract them in any way that
+ * it chooses. Ideally, it should choose a method that maximizes
+ * performance.
+ *
+ * The target string will be provided in ctx->common.target. This might
+ * be a directory, although extraction backends are free to interpret it
+ * as they wish. TODO: in some cases, the common extraction code also
+ * interprets the target string. This should be completely isolated to
+ * extraction backends.
+ *
+ * The extraction flags will be provided in ctx->common.extract_flags.
+ * Extraction backends should examine them and implement the behaviors
+ * for as many flags as possible. Some flags are already handled by the
+ * common extraction code. TODO: this needs to be better formalized.
+ *
+ * @dentry_list, the list of dentries, will be ordered such that the
+ * ancestor of any dentry always precedes any descendents. Unless
+ * @single_tree_only is set, it's possible that the dentries consist of
+ * multiple disconnected trees.
+ *
+ * 'd_extraction_name' and 'd_extraction_name_nchars' of each dentry
+ * will be set to indicate the actual name with which the dentry should
+ * be extracted. This may or may not be the same as 'file_name'.
+ * TODO: really, the extraction backends should be responsible for
+ * generating 'd_extraction_name'.
+ *
+ * Each dentry will refer to a valid inode in 'd_inode'.
+ * 'd_inode->i_extraction_aliases' will contain a list of just the
+ * dentries of that inode being extracted. This will be a (possibly
+ * nonproper) subset of the 'd_inode->i_dentry' list.
+ *
+ * The streams required to be extracted will already be prepared in
+ * 'apply_ctx'. The extraction backend should call
+ * extract_stream_list() to extract them.
+ *
+ * The will_extract_dentry() utility function, given an arbitrary dentry
+ * in the WIM image (which may not be in the extraction list), can be
+ * used to determine if that dentry is in the extraction list.
+ *
+ * Return 0 if successful; otherwise a positive wimlib error code.
+ */
int (*extract)(struct list_head *dentry_list, struct apply_ctx *ctx);
+ /*
+ * Query whether the unnamed data stream of the specified file will be
+ * extracted as "externally backed". If so, the extraction backend is
+ * assumed to handle this separately, and the common extraction code
+ * will not register a usage of that stream.
+ *
+ * This routine is optional.
+ *
+ * Return:
+ * < 0 if the file will *not* be externally backed.
+ * = 0 if the file will be externally backed.
+ * > 0 (wimlib error code) if another error occurred.
+ */
+ int (*will_externally_back)(struct wim_dentry *dentry, struct apply_ctx *ctx);
+
+ /*
+ * Size of the backend-specific extraction context. It must contain
+ * 'struct apply_ctx' as its first member.
+ */
size_t context_size;
+
+ /*
+ * Set this if the extraction backend only supports extracting dentries
+ * that form a single tree, not multiple trees.
+ */
bool single_tree_only;
};
}
static int
-dentry_ref_streams(struct wim_dentry *dentry, struct apply_ctx *ctx)
+ref_unnamed_stream(struct wim_dentry *dentry, struct apply_ctx *ctx)
{
struct wim_inode *inode = dentry->d_inode;
int ret;
+ u16 stream_idx;
+ struct wim_lookup_table_entry *stream;
- /* The unnamed data stream will always be extracted, except in an
- * unlikely case. */
- if (!inode_is_encrypted_directory(inode)) {
- u16 stream_idx;
- struct wim_lookup_table_entry *stream;
+ if (unlikely(inode_is_encrypted_directory(inode)))
+ return 0;
- stream = inode_unnamed_stream_resolved(inode, &stream_idx);
- ret = ref_stream(stream, stream_idx, dentry, ctx);
- if (ret)
- return ret;
+ if (unlikely(ctx->apply_ops->will_externally_back)) {
+ ret = (*ctx->apply_ops->will_externally_back)(dentry, ctx);
+ if (ret >= 0) {
+ if (ret) /* Error */
+ return ret;
+ /* Will externally back */
+ return 0;
+ }
+ /* Won't externally back */
}
+ stream = inode_unnamed_stream_resolved(inode, &stream_idx);
+ return ref_stream(stream, stream_idx, dentry, ctx);
+}
+
+static int
+dentry_ref_streams(struct wim_dentry *dentry, struct apply_ctx *ctx)
+{
+ struct wim_inode *inode = dentry->d_inode;
+ int ret;
+
+ /* The unnamed data stream will almost always be extracted, but there
+ * exist cases in which it won't be. */
+ ret = ref_unnamed_stream(dentry, ctx);
+ if (ret)
+ return ret;
+
/* Named data streams will be extracted only if supported in the current
* extraction mode and volume, and to avoid complications, if not doing
* a linked extraction. */
}
INIT_LIST_HEAD(&ctx->stream_list);
filedes_invalidate(&ctx->tmpfile_fd);
+ ctx->apply_ops = ops;
ret = (*ops->get_supported_features)(target, &ctx->supported_features);
if (ret)
wcslen(dentry->_full_path), pats);
}
+static const wchar_t *
+current_path(struct win32_apply_ctx *ctx);
+
+static void
+build_extraction_path(const struct wim_dentry *dentry,
+ struct win32_apply_ctx *ctx);
+
+#define WIM_BACKING_NOT_ENABLED -1
+#define WIM_BACKING_NOT_POSSIBLE -2
+#define WIM_BACKING_EXCLUDED -3
+
+/*
+ * Determines if the unnamed data stream of a file will be created as an
+ * external backing, as opposed to a standard extraction.
+ */
+static int
+win32_will_externally_back(struct wim_dentry *dentry, struct apply_ctx *_ctx)
+{
+ struct win32_apply_ctx *ctx = (struct win32_apply_ctx *)_ctx;
+ struct wim_lookup_table_entry *stream;
+ int ret;
+
+ if (!(ctx->common.extract_flags & WIMLIB_EXTRACT_FLAG_WIMBOOT))
+ return WIM_BACKING_NOT_ENABLED;
+
+ if (dentry->d_inode->i_attributes & (FILE_ATTRIBUTE_DIRECTORY |
+ FILE_ATTRIBUTE_REPARSE_POINT |
+ FILE_ATTRIBUTE_ENCRYPTED))
+ return WIM_BACKING_NOT_POSSIBLE;
+
+ stream = inode_unnamed_lte_resolved(dentry->d_inode);
+
+ if (!stream ||
+ stream->resource_location != RESOURCE_IN_WIM ||
+ stream->rspec->wim != ctx->common.wim ||
+ stream->size != stream->rspec->uncompressed_size)
+ return WIM_BACKING_NOT_POSSIBLE;
+
+ ret = calculate_dentry_full_path(dentry);
+ if (ret)
+ return ret;
+
+ if (in_prepopulate_list(dentry, ctx))
+ return WIM_BACKING_EXCLUDED;
+
+ return 0;
+}
+
+static int
+set_external_backing(struct wim_dentry *dentry, struct win32_apply_ctx *ctx)
+{
+ int ret;
+
+ ret = win32_will_externally_back(dentry, &ctx->common);
+ if (ret > 0) /* Error. */
+ return ret;
+
+ if (ret < 0 && ret != WIM_BACKING_EXCLUDED)
+ return 0; /* Not externally backing, other than due to exclusion. */
+
+ build_extraction_path(dentry, ctx);
+
+ if (ret == WIM_BACKING_EXCLUDED) {
+ /* Not externally backing due to exclusion. */
+ union wimlib_progress_info info;
+
+ info.wimboot_exclude.path_in_wim = dentry->_full_path;
+ info.wimboot_exclude.extraction_path = current_path(ctx);
+
+ return call_progress(ctx->common.progfunc,
+ WIMLIB_PROGRESS_MSG_WIMBOOT_EXCLUDE,
+ &info, ctx->common.progctx);
+ } else {
+ /* Externally backing. */
+ return wimboot_set_pointer(&ctx->attr,
+ current_path(ctx),
+ inode_unnamed_lte_resolved(dentry->d_inode),
+ ctx->wimboot.data_source_id,
+ ctx->wimboot.wim_lookup_table_hash,
+ ctx->wimboot.wof_running);
+ }
+}
+
/* Calculates the SHA-1 message digest of the WIM's lookup table. */
static int
hash_lookup_table(WIMStruct *wim, u8 hash[SHA1_HASH_SIZE])
/* When creating an inode that will have a short (DOS) name, we create it using
* the long name associated with the short name. This ensures that the short
* name gets associated with the correct long name. */
-static const struct wim_dentry *
+static struct wim_dentry *
first_extraction_alias(const struct wim_inode *inode)
{
- const struct list_head *next = inode->i_extraction_aliases.next;
- const struct wim_dentry *dentry;
+ struct list_head *next = inode->i_extraction_aliases.next;
+ struct wim_dentry *dentry;
do {
dentry = list_entry(next, struct wim_dentry,
static int
create_nondirectory(const struct wim_inode *inode, struct win32_apply_ctx *ctx)
{
- const struct wim_dentry *first_dentry;
+ struct wim_dentry *first_dentry;
HANDLE h;
int ret;
if (!ret)
ret = create_links(h, first_dentry, ctx);
+ /* "WIMBoot" extraction: set external backing by the WIM file if needed. */
+ if (!ret && unlikely(ctx->common.extract_flags & WIMLIB_EXTRACT_FLAG_WIMBOOT))
+ ret = set_external_backing(first_dentry, ctx);
+
(*func_NtClose)(h);
return ret;
}
return prepare_data_buffer(ctx, stream->size);
}
- /* Extracting unnamed data stream in WIMBoot mode? */
- if (unlikely(ctx->common.extract_flags & WIMLIB_EXTRACT_FLAG_WIMBOOT)
- && (stream_name_nchars == 0)
- && (stream->resource_location == RESOURCE_IN_WIM)
- && (stream->rspec->wim == ctx->common.wim)
- && (stream->size == stream->rspec->uncompressed_size))
- {
- int ret = calculate_dentry_full_path(dentry);
- if (ret)
- return ret;
- if (in_prepopulate_list(dentry, ctx)) {
- union wimlib_progress_info info;
-
- info.wimboot_exclude.path_in_wim = dentry->_full_path;
- info.wimboot_exclude.extraction_path = current_path(ctx);
-
- ret = call_progress(ctx->common.progfunc,
- WIMLIB_PROGRESS_MSG_WIMBOOT_EXCLUDE,
- &info, ctx->common.progctx);
- FREE(dentry->_full_path);
- dentry->_full_path = NULL;
- if (ret)
- return ret;
- /* Go on and open the file for normal extraction. */
- } else {
- FREE(dentry->_full_path);
- dentry->_full_path = NULL;
- return wimboot_set_pointer(&ctx->attr,
- current_path(ctx),
- stream,
- ctx->wimboot.data_source_id,
- ctx->wimboot.wim_lookup_table_hash,
- ctx->wimboot.wof_running);
- }
- }
-
if (ctx->num_open_handles == MAX_OPEN_STREAMS) {
/* XXX: Fix this. But because of the checks in
* extract_stream_list(), this can now only happen on a
.name = "Windows",
.get_supported_features = win32_get_supported_features,
.extract = win32_extract,
+ .will_externally_back = win32_will_externally_back,
.context_size = sizeof(struct win32_apply_ctx),
};
git://wimlib.net / wimlib / commitdiff