[wimlib] / include / wimlib / inode.h

#ifndef _WIMLIB_INODE_H
#define _WIMLIB_INODE_H

#include "wimlib/assert.h"
#include "wimlib/list.h"
#include "wimlib/lookup_table.h"
#include "wimlib/sha1.h"

#include <string.h>

struct wim_ads_entry;
struct wim_dentry;
struct wim_security_data;
struct wim_lookup_table;
struct wimfs_fd;
struct avl_tree_node;

/*
 * WIM inode.
 *
 * As mentioned in the comment above `struct wim_dentry', in WIM files there
 * is no on-disk analogue of a real inode, as most of these fields are
 * duplicated in the dentries.  Instead, a `struct wim_inode' is something we
 * create ourselves to simplify the handling of hard links.
 */
struct wim_inode {
        /* If i_resolved == 0:
         *      SHA1 message digest of the contents of the unnamed-data stream
         *      of this inode.
         *
         * If i_resolved == 1:
         *      Pointer to the lookup table entry for the unnamed data stream
         *      of this inode, or NULL.
         *
         * i_hash corresponds to the 'unnamed_stream_hash' field of the `struct
         * wim_dentry_on_disk' and the additional caveats documented about that
         * field apply here (for example, the quirks regarding all-zero hashes).
         */
        union {
                u8 i_hash[SHA1_HASH_SIZE];
                struct wim_lookup_table_entry *i_lte;
        };

        /* Corresponds to the 'attributes' field of `struct wim_dentry_on_disk';
         * bitwise OR of the FILE_ATTRIBUTE_* flags that give the attributes of
         * this inode. */
        u32 i_attributes;

        /* Root of a balanced binary search tree storing the child directory
         * entries of this inode, if any.  Keyed by wim_dentry->file_name, case
         * sensitively.  If this inode is not a directory or if it has no
         * children then this will be an empty tree (NULL).  */
        struct avl_tree_node *i_children;

        /* Root of a balanced binary search tree storing the child directory
         * entries of this inode, if any.  Keyed by wim_dentry->file_name, case
         * insensitively.  If this inode is not a directory or if it has no
         * children then this will be an empty tree (NULL).  */
        struct avl_tree_node *i_children_ci;

        /* List of dentries that are aliases for this inode.  There will be
         * i_nlink dentries in this list.  */
        struct list_head i_dentry;

        /* Field to place this inode into a list. */
        union {
                /* Hash list node- used in inode_fixup.c when the inodes are
                 * placed into a hash table keyed by inode number and optionally
                 * device number, in order to detect dentries that are aliases
                 * for the same inode. */
                struct hlist_node i_hlist;

                /* Normal list node- used to connect all the inodes of a WIM image
                 * into a single linked list referenced from the
                 * `struct wim_image_metadata' for that image. */
                struct list_head i_list;
        };

        /* Number of dentries that are aliases for this inode.  */
        u32 i_nlink;

        /* Number of alternate data streams (ADS) associated with this inode */
        u16 i_num_ads;

        /* Flag that indicates whether this inode's streams have been
         * "resolved".  By default, the inode starts as "unresolved", meaning
         * that the i_hash field, along with the hash field of any associated
         * wim_ads_entry's, are valid and should be used as keys in the WIM
         * lookup table to find the associated `struct wim_lookup_table_entry'.
         * But if the inode has been resolved, then each of these fields is
         * replaced with a pointer directly to the appropriate `struct
         * wim_lookup_table_entry', or NULL if the stream is empty.  */
        u8 i_resolved : 1;

        /* Flag used to mark this inode as visited; this is used when visiting
         * all the inodes in a dentry tree exactly once.  It will be 0 by
         * default and must be cleared following the tree traversal, even in
         * error paths.  */
        u8 i_visited : 1;

        /* 1 iff all ADS entries of this inode are named or if this inode
         * has no ADS entries  */
        u8 i_canonical_streams : 1;

        /* Cached value  */
        u8 i_can_externally_back : 1;

        /* Pointer to a malloc()ed array of i_num_ads alternate data stream
         * entries for this inode.  */
        struct wim_ads_entry *i_ads_entries;

        /* If not NULL, a pointer to the extra data that was read from the
         * dentry.  This should be a series of tagged items, each of which
         * represents a bit of extra metadata, such as the file's object ID.
         * See tagged_items.c for more information.  */
        void *i_extra;

        /* Size of @i_extra buffer in bytes.  If 0, there is no extra data.  */
        size_t i_extra_size;

        /* Creation time, last access time, and last write time for this inode, in
         * 100-nanosecond intervals since 12:00 a.m UTC January 1, 1601.  They
         * should correspond to the times gotten by calling GetFileTime() on
         * Windows. */
        u64 i_creation_time;
        u64 i_last_access_time;
        u64 i_last_write_time;

        /* Corresponds to 'security_id' in `struct wim_dentry_on_disk':  The
         * index of this inode's security descriptor in the WIM image's table of
         * security descriptors, or -1.  Note: when a WIM image is loaded,
         * wimlib sets out-of-bounds indices and values less than -1 in this
         * field to -1.  So the extraction code need not do an upper bound check
         * after checking for -1 (or equivalently < 0).  */
        int32_t i_security_id;

        /* Identity of a reparse point.  See
         * http://msdn.microsoft.com/en-us/library/windows/desktop/aa365503(v=vs.85).aspx
         * for what a reparse point is. */
        u32 i_reparse_tag;

        /* Unused/unknown fields that we just read into memory so we can
         * re-write them unchanged.  */
        u32 i_rp_unknown_1;
        u16 i_rp_unknown_2;

        /* Corresponds to not_rpfixed in `struct wim_dentry_on_disk':  Set to 0
         * if reparse point fixups have been done.  Otherwise set to 1.  Note:
         * this actually may reflect the SYMBOLIC_LINK_RELATIVE flag.
         */
        u16 i_not_rpfixed;

        /* Inode number; corresponds to hard_link_group_id in the `struct
         * wim_dentry_on_disk'.  */
        u64 i_ino;

        union {
                /* Device number, used only during image capture, so we can
                 * identify hard linked files by the combination of inode number
                 * and device number (rather than just inode number, which could
                 * be ambigious if the captured tree spans a mountpoint).  Set
                 * to 0 otherwise.  */
                u64 i_devno;

                /* Fields used only during extraction  */
                struct {
                        /* List of aliases of this dentry that are being
                         * extracted in the current extraction operation.  This
                         * will be a (possibly nonproper) subset of the dentries
                         * in the i_dentry list.  This list will be constructed
                         * regardless of whether the extraction backend supports
                         * hard links or not.  */
                        struct list_head i_extraction_aliases;

                #ifdef WITH_NTFS_3G
                        /* In NTFS-3g extraction mode, this is set to the Master
                         * File Table (MFT) number of the NTFS file that was
                         * created for this inode.  */
                        u64 i_mft_no;
                #endif
                };

                /* Used during WIM writing with
                 * WIMLIB_WRITE_FLAG_SEND_DONE_WITH_FILE_MESSAGES:  the number
                 * of data streams this inode has that have not yet been fully
                 * read.  */
                u32 num_remaining_streams;

#ifdef WITH_FUSE
                struct {
                        /* Used only during image mount:  Table of file
                         * descriptors that have been opened to this inode.
                         * This table is freed when the last file descriptor is
                         * closed.  */
                        struct wimfs_fd **i_fds;

                        /* Lower bound on the index of the next available entry
                         * in 'i_fds'.  */
                        u16 i_next_fd;
                };
#endif
        };

#ifdef WITH_FUSE
        u16 i_num_opened_fds;
        u16 i_num_allocated_fds;
#endif

        /* Next alternate data stream ID to be assigned */
        u32 i_next_stream_id;
};

/* Alternate data stream entry.
 *
 * We read this from disk in the read_ads_entries() function; see that function
 * for more explanation. */
struct wim_ads_entry {
        union {
                /* SHA-1 message digest of stream contents */
                u8 hash[SHA1_HASH_SIZE];

                /* The corresponding lookup table entry (only for resolved
                 * streams) */
                struct wim_lookup_table_entry *lte;
        };

        /* Length of UTF16-encoded stream name, in bytes, not including the
         * terminating null character; or 0 if the stream is unnamed. */
        u16 stream_name_nbytes;

        /* Number to identify an alternate data stream even after it's possibly
         * been moved or renamed. */
        u32 stream_id;

        /* Stream name (UTF-16LE), null-terminated, or NULL if the stream is
         * unnamed.  */
        utf16lechar *stream_name;

        /* Reserved field.  We read it into memory so we can write it out
         * unchanged. */
        u64 reserved;
};

/* WIM alternate data stream entry (on-disk format) */
struct wim_ads_entry_on_disk {
        /*  Length of the entry, in bytes.  This apparently includes all
         *  fixed-length fields, plus the stream name and null terminator if
         *  present, and the padding up to an 8 byte boundary.  wimlib is a
         *  little less strict when reading the entries, and only requires that
         *  the number of bytes from this field is at least as large as the size
         *  of the fixed length fields and stream name without null terminator.
         *  */
        le64  length;

        le64  reserved;

        /* SHA1 message digest of the uncompressed stream; or, alternatively,
         * can be all zeroes if the stream has zero length. */
        u8 hash[SHA1_HASH_SIZE];

        /* Length of the stream name, in bytes.  0 if the stream is unnamed.  */
        le16 stream_name_nbytes;

        /* Stream name in UTF-16LE.  It is @stream_name_nbytes bytes long,
         * excluding the null terminator.  There is a null terminator
         * character if @stream_name_nbytes != 0; i.e., if this stream is named.
         * */
        utf16lechar stream_name[];
} _packed_attribute;

#define WIM_ADS_ENTRY_DISK_SIZE 38

/*
 * Reparse tags documented at
 * http://msdn.microsoft.com/en-us/library/dd541667(v=prot.10).aspx
 */
#define WIM_IO_REPARSE_TAG_RESERVED_ZERO        0x00000000
#define WIM_IO_REPARSE_TAG_RESERVED_ONE         0x00000001
#define WIM_IO_REPARSE_TAG_MOUNT_POINT          0xA0000003
#define WIM_IO_REPARSE_TAG_HSM                  0xC0000004
#define WIM_IO_REPARSE_TAG_HSM2                 0x80000006
#define WIM_IO_REPARSE_TAG_DRIVER_EXTENDER      0x80000005
#define WIM_IO_REPARSE_TAG_SIS                  0x80000007
#define WIM_IO_REPARSE_TAG_DFS                  0x8000000A
#define WIM_IO_REPARSE_TAG_DFSR                 0x80000012
#define WIM_IO_REPARSE_TAG_FILTER_MANAGER       0x8000000B
#define WIM_IO_REPARSE_TAG_SYMLINK              0xA000000C

#define FILE_ATTRIBUTE_READONLY            0x00000001
#define FILE_ATTRIBUTE_HIDDEN              0x00000002
#define FILE_ATTRIBUTE_SYSTEM              0x00000004
#define FILE_ATTRIBUTE_DIRECTORY           0x00000010
#define FILE_ATTRIBUTE_ARCHIVE             0x00000020
#define FILE_ATTRIBUTE_DEVICE              0x00000040
#define FILE_ATTRIBUTE_NORMAL              0x00000080
#define FILE_ATTRIBUTE_TEMPORARY           0x00000100
#define FILE_ATTRIBUTE_SPARSE_FILE         0x00000200
#define FILE_ATTRIBUTE_REPARSE_POINT       0x00000400
#define FILE_ATTRIBUTE_COMPRESSED          0x00000800
#define FILE_ATTRIBUTE_OFFLINE             0x00001000
#define FILE_ATTRIBUTE_NOT_CONTENT_INDEXED 0x00002000
#define FILE_ATTRIBUTE_ENCRYPTED           0x00004000
#define FILE_ATTRIBUTE_VIRTUAL             0x00010000

extern struct wim_inode *
new_inode(void) _malloc_attribute;

extern struct wim_inode *
new_timeless_inode(void) _malloc_attribute;

extern void
put_inode(struct wim_inode *inode);

extern void
free_inode(struct wim_inode *inode);

/* Iterate through each alias of an inode.  */
#define inode_for_each_dentry(dentry, inode) \
                list_for_each_entry((dentry), &(inode)->i_dentry, d_alias)

/* Add a new alias for an inode.  Does not increment i_nlink; that must be done
 * separately.  */
#define inode_add_dentry(dentry, inode) \
                list_add_tail(&(dentry)->d_alias, &(inode)->i_dentry)

/* Return an alias of an inode.  */
#define inode_first_dentry(inode) \
                container_of(inode->i_dentry.next, struct wim_dentry, d_alias)

/* Return the full path of an alias of an inode, or NULL if it could not be
 * determined.  */
#define inode_first_full_path(inode) \
                dentry_full_path(inode_first_dentry(inode))

extern struct wim_ads_entry *
inode_get_ads_entry(struct wim_inode *inode, const tchar *stream_name);

extern struct wim_ads_entry *
inode_add_ads_utf16le(struct wim_inode *inode,
                      const utf16lechar *stream_name,
                      size_t stream_name_nbytes);

extern struct wim_ads_entry *
inode_add_ads(struct wim_inode *dentry, const tchar *stream_name);

extern struct wim_ads_entry *
inode_add_ads_with_data(struct wim_inode *inode, const tchar *name,
                        const void *value, size_t size,
                        struct wim_lookup_table *lookup_table);

extern bool
inode_has_named_stream(const struct wim_inode *inode);

extern int
inode_set_unnamed_stream(struct wim_inode *inode, const void *data, size_t len,
                         struct wim_lookup_table *lookup_table);

extern void
inode_remove_ads(struct wim_inode *inode, struct wim_ads_entry *entry,
                 struct wim_lookup_table *lookup_table);

/*
 * Does the specified alternate data stream entry correspond to a named stream?
 *
 * See inode_needs_dummy_stream() for explanation of why an alternate data
 * stream entry might, in fact, not be named...
 */
static inline bool
ads_entry_is_named_stream(const struct wim_ads_entry *entry)
{
        return entry->stream_name_nbytes != 0;
}

/* Is the inode a directory?
 * This doesn't count directories with reparse data.
 * wimlib only allows inodes of this type to have children.
 */
static inline bool
inode_is_directory(const struct wim_inode *inode)
{
        return (inode->i_attributes & (FILE_ATTRIBUTE_DIRECTORY |
                                       FILE_ATTRIBUTE_REPARSE_POINT))
                        == FILE_ATTRIBUTE_DIRECTORY;
}

/* Is the inode a directory with the encrypted attribute set?
 * This currently returns true for encrypted directories even if they have
 * reparse data (not sure if such files can even exist).  */
static inline bool
inode_is_encrypted_directory(const struct wim_inode *inode)
{
        return ((inode->i_attributes & (FILE_ATTRIBUTE_DIRECTORY |
                                        FILE_ATTRIBUTE_ENCRYPTED))
                == (FILE_ATTRIBUTE_DIRECTORY | FILE_ATTRIBUTE_ENCRYPTED));
}

/* Is the inode a symbolic link?
 * This returns true iff the inode is a reparse point that is either a "real"
 * symbolic link or a junction point.  */
static inline bool
inode_is_symlink(const struct wim_inode *inode)
{
        return (inode->i_attributes & FILE_ATTRIBUTE_REPARSE_POINT)
                && (inode->i_reparse_tag == WIM_IO_REPARSE_TAG_SYMLINK ||
                    inode->i_reparse_tag == WIM_IO_REPARSE_TAG_MOUNT_POINT);
}

/* Does the inode have children?
 * Currently (based on read_dentry_tree()), this can only return true for inodes
 * for which inode_is_directory() returns true.  (This also returns false on
 * empty directories.)  */
static inline bool
inode_has_children(const struct wim_inode *inode)
{
        return inode->i_children != NULL;
}

extern int
inode_resolve_streams(struct wim_inode *inode, struct wim_lookup_table *table,
                      bool force);

extern int
stream_not_found_error(const struct wim_inode *inode, const u8 *hash);

extern void
inode_unresolve_streams(struct wim_inode *inode);

static inline struct wim_lookup_table_entry *
inode_stream_lte_resolved(const struct wim_inode *inode, unsigned stream_idx)
{
        wimlib_assert(inode->i_resolved);
        wimlib_assert(stream_idx <= inode->i_num_ads);
        if (stream_idx == 0)
                return inode->i_lte;
        else
                return inode->i_ads_entries[stream_idx - 1].lte;
}

static inline struct wim_lookup_table_entry *
inode_stream_lte_unresolved(const struct wim_inode *inode, unsigned stream_idx,
                            const struct wim_lookup_table *table)
{
        wimlib_assert(!inode->i_resolved);
        wimlib_assert(stream_idx <= inode->i_num_ads);
        if (table == NULL)
                return NULL;
        if (stream_idx == 0)
                return lookup_stream(table, inode->i_hash);
        else
                return lookup_stream(table, inode->i_ads_entries[ stream_idx - 1].hash);
}

extern struct wim_lookup_table_entry *
inode_stream_lte(const struct wim_inode *inode, unsigned stream_idx,
                 const struct wim_lookup_table *table);

static inline const u8 *
inode_stream_hash_unresolved(const struct wim_inode *inode, unsigned stream_idx)
{
        wimlib_assert(!inode->i_resolved);
        wimlib_assert(stream_idx <= inode->i_num_ads);
        if (stream_idx == 0)
                return inode->i_hash;
        else
                return inode->i_ads_entries[stream_idx - 1].hash;
}


static inline const u8 *
inode_stream_hash_resolved(const struct wim_inode *inode, unsigned stream_idx)
{
        struct wim_lookup_table_entry *lte;
        lte = inode_stream_lte_resolved(inode, stream_idx);
        if (lte)
                return lte->hash;
        else
                return zero_hash;
}

/*
 * Returns the hash for stream @stream_idx of the inode, where stream_idx = 0
 * means the default un-named file stream, and stream_idx >= 1 corresponds to an
 * alternate data stream.
 *
 * This works for both resolved and un-resolved dentries.
 */
static inline const u8 *
inode_stream_hash(const struct wim_inode *inode, unsigned stream_idx)
{
        if (inode->i_resolved)
                return inode_stream_hash_resolved(inode, stream_idx);
        else
                return inode_stream_hash_unresolved(inode, stream_idx);
}

static inline u16
inode_stream_name_nbytes(const struct wim_inode *inode, unsigned stream_idx)
{
        wimlib_assert(stream_idx <= inode->i_num_ads);
        if (stream_idx == 0)
                return 0;
        else
                return inode->i_ads_entries[stream_idx - 1].stream_name_nbytes;
}

static inline u32
inode_stream_idx_to_id(const struct wim_inode *inode, unsigned stream_idx)
{
        if (stream_idx == 0)
                return 0;
        else
                return inode->i_ads_entries[stream_idx - 1].stream_id;
}

extern struct wim_lookup_table_entry *
inode_unnamed_stream_resolved(const struct wim_inode *inode, u16 *stream_idx_ret);

extern struct wim_lookup_table_entry *
inode_unnamed_lte_resolved(const struct wim_inode *inode);

extern struct wim_lookup_table_entry *
inode_unnamed_lte_unresolved(const struct wim_inode *inode,
                             const struct wim_lookup_table *table);

extern struct wim_lookup_table_entry *
inode_unnamed_lte(const struct wim_inode *inode, const struct wim_lookup_table *table);

extern const u8 *
inode_unnamed_stream_hash(const struct wim_inode *inode);

extern int
read_ads_entries(const u8 * restrict p, struct wim_inode * restrict inode,
                 size_t *nbytes_remaining_p);

extern void
check_inode(struct wim_inode *inode, const struct wim_security_data *sd);

extern void
inode_ref_streams(struct wim_inode *inode);

extern void
inode_unref_streams(struct wim_inode *inode,
                    struct wim_lookup_table *lookup_table);

/* inode_fixup.c  */
extern int
dentry_tree_fix_inodes(struct wim_dentry *root, struct list_head *inode_list);

#endif /* _WIMLIB_INODE_H  */