WIM capture: Share inodes immediately

[wimlib] / src / dentry.h

#ifndef _WIMLIB_DENTRY_H
#define _WIMLIB_DENTRY_H

#include "util.h"
#include "config.h"
#include "list.h"
#include "sha1.h"
#include "rbtree.h"
#include <string.h>

#ifdef WITH_FUSE
#include <pthread.h>
#endif

struct stat;
struct wim_lookup_table;
struct WIMStruct;
struct wim_lookup_table_entry;
struct wimfs_fd;
struct wim_inode;
struct wim_dentry;

/* Size of the struct wim_dentry up to and including the file_name_len. */
#define WIM_DENTRY_DISK_SIZE    102

/* Size of on-disk WIM alternate data stream entry, in bytes, up to and
 * including the stream length field (see below). */
#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


/* 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. */
        u16 stream_name_nbytes;

        /* Stream name (UTF-16LE) */
        utf16lechar *stream_name;

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


static inline bool
ads_entries_have_same_name(const struct wim_ads_entry *entry_1,
                           const struct wim_ads_entry *entry_2)
{
        return entry_1->stream_name_nbytes == entry_2->stream_name_nbytes &&
               memcmp(entry_1->stream_name, entry_2->stream_name,
                      entry_1->stream_name_nbytes) == 0;
}

/*
 * In-memory structure for a WIM directory entry (dentry).  There is a directory
 * tree for each image in the WIM.
 *
 * Note that this is a directory entry and not an inode.  Since NTFS allows hard
 * links, it's possible for a NTFS inode to correspond to multiple WIM dentries.
 * The hard link group ID field of the on-disk WIM dentry tells us the number of
 * the NTFS inode that the dentry corresponds to (and this gets placed in
 * d_inode->i_ino).
 *
 * Unfortunately, WIM files do not have an analogue to an inode; instead certain
 * information, such as file attributes, the security descriptor, and file
 * streams is replicated in each hard-linked dentry, even though this
 * information really is associated with an inode.  In-memory, we fix up this
 * flaw by allocating a `struct wim_inode' for each dentry that contains some of
 * this duplicated information, then combining the inodes for each hard link
 * group together.
 *
 * Confusingly, it's possible for stream information to be missing from a dentry
 * in a hard link set, in which case the stream information needs to be gotten
 * from one of the other dentries in the hard link set.  In addition, it is
 * possible for dentries to have inconsistent security IDs, file attributes, or
 * file streams when they share the same hard link ID (don't even ask.  I hope
 * that Microsoft may have fixed this problem, since I've only noticed it in the
 * 'install.wim' for Windows 7).  For those dentries, we have to use the
 * conflicting fields to split up the hard link groups.  (See
 * dentry_tree_fix_inodes() in hardlink.c).
 */
struct wim_dentry {
        /* The inode for this dentry */
        struct wim_inode *d_inode;

        /* Red-black tree of sibling dentries */
        struct rb_node rb_node;

        /* Length of UTF-16LE encoded short filename, in bytes, not including
         * the terminating zero wide-character. */
        u16 short_name_nbytes;

        /* Length of UTF-16LE encoded "long" file name, in bytes, not including
         * the terminating null character. */
        u16 file_name_nbytes;

        /* Length of full path name encoded using "tchars", in bytes, not
         * including the terminating null character. */
        u32 full_path_nbytes;

        /* Has this dentry been extracted yet? */
        u8 is_extracted : 1;

        /* Only used during NTFS capture */
        u8 is_win32_name : 1;

        /* Temporary list */
        struct list_head tmp_list;

        /* List of dentries in the inode (hard link set)  */
        struct list_head d_alias;

        /* The parent of this directory entry. */
        struct wim_dentry *parent;

        /*
         * Size of directory entry on disk, in bytes.  Typical size is around
         * 104 to 120 bytes.
         *
         * It is possible for the length field to be 0.  This situation, which
         * is undocumented, indicates the end of a list of sibling nodes in a
         * directory.  It also means the real length is 8, because the dentry
         * included only the length field, but that takes up 8 bytes.
         *
         * The length here includes the base directory entry on disk as well as
         * the long and short filenames.  It does NOT include any alternate
         * stream entries that may follow the directory entry, even though the
         * size of those needs to be considered.  The length SHOULD be 8-byte
         * aligned, although we don't require it to be.  We do require the
         * length to be large enough to hold the file name(s) of the dentry;
         * additionally, a warning is issued if this field is larger than the
         * aligned size.
         */
        u64 length;

        /* The offset, from the start of the uncompressed WIM metadata resource
         * for this image, of this dentry's child dentries.  0 if the directory
         * entry has no children, which is the case for regular files or reparse
         * points. */
        u64 subdir_offset;

        /* Number of references to the dentry tree itself, as in multiple
         * WIMStructs */
        u32 refcnt;

        /* Pointer to the UTF-16LE short filename (malloc()ed buffer) */
        utf16lechar *short_name;

        /* Pointer to the UTF-16LE filename (malloc()ed buffer). */
        utf16lechar *file_name;

        /* Full path of this dentry */
        tchar *full_path;
};

#define rbnode_dentry(node) container_of(node, struct wim_dentry, rb_node)

/*
 * WIM inode.
 *
 * As mentioned above, in the WIM file that is no on-disk analogue of a real
 * inode, as most of these fields are duplicated in the dentries.
 */
struct wim_inode {
        /* Timestamps for the inode.  The timestamps are the number of
         * 100-nanosecond intervals that have elapsed since 12:00 A.M., January
         * 1st, 1601, UTC.  This is the same format used in NTFS inodes. */
        u64 i_creation_time;
        u64 i_last_access_time;
        u64 i_last_write_time;

        /* The file attributes associated with this inode.  This is a bitwise OR
         * of the FILE_ATTRIBUTE_* flags. */
        u32 i_attributes;

        /* The index of the security descriptor in the WIM image's table of
         * security descriptors that contains this file's security information.
         * If -1, no security information exists for this file.  */
        int32_t i_security_id;

        /* %true iff the inode's lookup table entries has been resolved (i.e.
         * the @lte field is valid, but the @hash field is not valid)
         *
         * (This is not an on-disk field.) */
        u8 i_resolved : 1;

        /* %true iff verify_inode() has run on this inode. */
        u8 i_verified : 1;

        /* Used only in NTFS-mode extraction */
        u8 i_dos_name_extracted : 1;

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

        /* A hash of the file's contents, or a pointer to the lookup table entry
         * for this dentry if the lookup table entries have been resolved.
         *
         * More specifically, this is for the un-named default file stream, as
         * opposed to the alternate (named) file streams, which may have their
         * own lookup table entries.  */
        union {
                u8 i_hash[SHA1_HASH_SIZE];
                struct wim_lookup_table_entry *i_lte;
        };

        /* 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;

        /* Number of dentries that reference this inode */
        u32 i_nlink;

        /* Alternate data stream entries. */
        struct wim_ads_entry *i_ads_entries;

        /* Inode number */
        u64 i_ino;

        /* List of dentries that reference this inode (there should be
         * link_count of them) */
        struct list_head i_dentry;

        struct hlist_node i_hlist;

        union {
                /* Used during image extraction to build a list of inodes that
                 * share a certain stream */
                struct list_head i_lte_inode_list;

                /* Device number, used only during image capture */
                u64 i_devno;
        };

        tchar *i_extracted_file;

        /* Root of a red-black tree storing the children of this inode (if
         * non-empty, implies the inode is a directory, although that is also
         * noted in the @attributes field.) */
        struct rb_root i_children;

#ifdef WITH_FUSE
        /* wimfs file descriptors table for the inode */
        u16 i_num_opened_fds;
        u16 i_num_allocated_fds;
        struct wimfs_fd **i_fds;

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

        /* This mutex protects the inode's file descriptors table during
         * read-only mounts.  Read-write mounts are still restricted to 1
         * thread. */
        pthread_mutex_t i_mutex;
#endif
};

#define inode_for_each_dentry(dentry, inode) \
                list_for_each_entry((dentry), &(inode)->i_dentry, d_alias)

#define inode_add_dentry(dentry, inode) \
                list_add_tail(&(dentry)->d_alias, &(inode)->i_dentry)

#define inode_first_dentry(inode) \
                container_of(inode->i_dentry.next, struct wim_dentry, d_alias)

static inline bool
dentry_is_first_in_inode(const struct wim_dentry *dentry)
{
        return inode_first_dentry(dentry->d_inode) == dentry;
}

extern u64
dentry_correct_total_length(const struct wim_dentry *dentry);

extern int
for_dentry_in_tree(struct wim_dentry *root,
                   int (*visitor)(struct wim_dentry*, void*),
                   void *args);

extern int
for_dentry_in_rbtree(struct rb_node *node,
                     int (*visitor)(struct wim_dentry *, void *),
                     void *arg);

static inline int
for_dentry_child(const struct wim_dentry *dentry,
                 int (*visitor)(struct wim_dentry *, void *),
                 void *arg)
{
        return for_dentry_in_rbtree(dentry->d_inode->i_children.rb_node,
                                    visitor,
                                    arg);
}

extern int
for_dentry_in_tree_depth(struct wim_dentry *root,
                         int (*visitor)(struct wim_dentry*, void*),
                         void *args);

extern int
calculate_dentry_full_path(struct wim_dentry *dentry, void *ignore);

extern void
calculate_subdir_offsets(struct wim_dentry *dentry, u64 *subdir_offset_p);

extern int
set_dentry_name(struct wim_dentry *dentry, const tchar *new_name);

extern struct wim_dentry *
get_dentry(struct WIMStruct *w, const tchar *path);

extern struct wim_inode *
wim_pathname_to_inode(struct WIMStruct *w, const tchar *path);

extern struct wim_dentry *
get_dentry_child_with_name(const struct wim_dentry *dentry,
                           const tchar *name);

extern struct wim_dentry *
get_dentry_child_with_utf16le_name(const struct wim_dentry *dentry,
                                   const utf16lechar *name,
                                   size_t name_nbytes);

extern struct wim_dentry *
get_parent_dentry(struct WIMStruct *w, const tchar *path);

extern int
print_dentry(struct wim_dentry *dentry, void *lookup_table);

extern int
print_dentry_full_path(struct wim_dentry *entry, void *ignore);

extern struct wim_inode *
new_timeless_inode();

extern int
new_dentry(const tchar *name, struct wim_dentry **dentry_ret);

extern int
new_dentry_with_inode(const tchar *name, struct wim_dentry **dentry_ret);

extern int
new_dentry_with_timeless_inode(const tchar *name, struct wim_dentry **dentry_ret);

extern void
free_inode(struct wim_inode *inode);

extern void
free_dentry(struct wim_dentry *dentry);

extern void
put_dentry(struct wim_dentry *dentry);

extern void
free_dentry_tree(struct wim_dentry *root,
                 struct wim_lookup_table *lookup_table);

extern int
increment_dentry_refcnt(struct wim_dentry *dentry, void *ignore);

extern void
unlink_dentry(struct wim_dentry *dentry);

extern bool
dentry_add_child(struct wim_dentry * restrict parent,
                 struct wim_dentry * restrict child);

extern struct wim_ads_entry *
inode_get_ads_entry(struct wim_inode *inode, const tchar *stream_name,
                    u16 *idx_ret);

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 int
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 void
inode_remove_ads(struct wim_inode *inode, u16 idx,
                 struct wim_lookup_table *lookup_table);


#define WIMLIB_UNIX_DATA_TAG "$$__wimlib_UNIX_data"
#define WIMLIB_UNIX_DATA_TAG_NBYTES (sizeof(WIMLIB_UNIX_DATA_TAG) - 1)

#define WIMLIB_UNIX_DATA_TAG_UTF16LE "$\0$\0_\0_\0w\0i\0m\0l\0i\0b\0_\0U\0N\0I\0X\0_\0d\0a\0t\0a\0"
#define WIMLIB_UNIX_DATA_TAG_UTF16LE_NBYTES (sizeof(WIMLIB_UNIX_DATA_TAG_UTF16LE) - 1)

/* Format for special alternate data stream entries to store UNIX data for files
 * and directories (see: WIMLIB_ADD_IMAGE_FLAG_UNIX_DATA) */
struct wimlib_unix_data {
        u16 version; /* Must be 0 */
        u16 uid;
        u16 gid;
        u16 mode;
} PACKED;

#ifndef __WIN32__

#define NO_UNIX_DATA (-1)
#define BAD_UNIX_DATA (-2)
extern int
inode_get_unix_data(const struct wim_inode *inode,
                    struct wimlib_unix_data *unix_data,
                    u16 *stream_idx_ret);

#define UNIX_DATA_UID    0x1
#define UNIX_DATA_GID    0x2
#define UNIX_DATA_MODE   0x4
#define UNIX_DATA_ALL    (UNIX_DATA_UID | UNIX_DATA_GID | UNIX_DATA_MODE)
#define UNIX_DATA_CREATE 0x8
extern int
inode_set_unix_data(struct wim_inode *inode, uid_t uid, gid_t gid, mode_t mode,
                    struct wim_lookup_table *lookup_table, int which);
#endif

extern int
read_dentry(const u8 metadata_resource[], u64 metadata_resource_len,
            u64 offset, struct wim_dentry *dentry);


extern int
read_dentry_tree(const u8 metadata_resource[], u64 metadata_resource_len,
                 struct wim_dentry *dentry);

extern u8 *
write_dentry_tree(const struct wim_dentry *tree, u8 *p);

static inline bool
dentry_is_root(const struct wim_dentry *dentry)
{
        return dentry->parent == dentry;
}

static inline bool
inode_is_directory(const struct wim_inode *inode)
{
        return (inode->i_attributes & FILE_ATTRIBUTE_DIRECTORY)
                && !(inode->i_attributes & FILE_ATTRIBUTE_REPARSE_POINT);
}

static inline bool
dentry_is_directory(const struct wim_dentry *dentry)
{
        return inode_is_directory(dentry->d_inode);
}

/* For our purposes, we consider "real" symlinks and "junction points" to both
 * be symlinks. */
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);
}

static inline bool
inode_is_regular_file(const struct wim_inode *inode)
{
        return !inode_is_directory(inode) && !inode_is_symlink(inode);
}

static inline bool
dentry_is_regular_file(const struct wim_dentry *dentry)
{
        return inode_is_regular_file(dentry->d_inode);
}

static inline bool
inode_has_children(const struct wim_inode *inode)
{
        return inode->i_children.rb_node != NULL;
}

static inline bool
dentry_has_children(const struct wim_dentry *dentry)
{
        return inode_has_children(dentry->d_inode);
}

static inline bool
dentry_has_short_name(const struct wim_dentry *dentry)
{
        return dentry->short_name_nbytes != 0;
}

static inline bool
dentry_has_long_name(const struct wim_dentry *dentry)
{
        return dentry->file_name_nbytes != 0;
}

#endif