/*
 * Server-side registry management
 *
 * Copyright (C) 1999 Alexandre Julliard
 */

/* To do:
 * - behavior with deleted keys
 * - values larger than request buffer
 * - symbolic links
 */

#include <assert.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include "object.h"
#include "handle.h"
#include "request.h"
#include "unicode.h"

#include "winbase.h"
#include "winerror.h"
#include "winreg.h"


/* a registry key */
struct key
{
    struct object     obj;         /* object header */
    WCHAR            *name;        /* key name */
    WCHAR            *class;       /* key class */
    struct key       *parent;      /* parent key */
    int               last_subkey; /* last in use subkey */
    int               nb_subkeys;  /* count of allocated subkeys */
    struct key      **subkeys;     /* subkeys array */
    int               last_value;  /* last in use value */
    int               nb_values;   /* count of allocated values in array */
    struct key_value *values;      /* values array */
    short             flags;       /* flags */
    short             level;       /* saving level */
    time_t            modif;       /* last modification time */
};

/* key flags */
#define KEY_VOLATILE 0x0001  /* key is volatile (not saved to disk) */
#define KEY_DELETED  0x0002  /* key has been deleted */
#define KEY_ROOT     0x0004  /* key is a root key */

/* a key value */
struct key_value
{
    WCHAR            *name;    /* value name */
    int               type;    /* value type */
    size_t            len;     /* value data length in bytes */
    void             *data;    /* pointer to value data */
};

#define MIN_SUBKEYS  8   /* min. number of allocated subkeys per key */
#define MIN_VALUES   8   /* min. number of allocated values per key */


/* the root keys */
#define HKEY_ROOT_FIRST   HKEY_CLASSES_ROOT
#define HKEY_ROOT_LAST    HKEY_DYN_DATA
#define NB_ROOT_KEYS      (HKEY_ROOT_LAST - HKEY_ROOT_FIRST + 1)
#define IS_ROOT_HKEY(h)   (((h) >= HKEY_ROOT_FIRST) && ((h) <= HKEY_ROOT_LAST))
static struct key *root_keys[NB_ROOT_KEYS];

static const char * const root_key_names[NB_ROOT_KEYS] =
{
    "HKEY_CLASSES_ROOT",
    "HKEY_CURRENT_USER",
    "HKEY_LOCAL_MACHINE",
    "HKEY_USERS",
    "HKEY_PERFORMANCE_DATA",
    "HKEY_CURRENT_CONFIG",
    "HKEY_DYN_DATA"
};


/* keys saving level */
/* current_level is the level that is put into all newly created or modified keys */
/* saving_level is the minimum level that a key needs in order to get saved */
static int current_level;
static int saving_level;

static int saving_version = 1;  /* file format version */


static void key_dump( struct object *obj, int verbose );
static void key_destroy( struct object *obj );

static const struct object_ops key_ops =
{
    sizeof(struct key),
    key_dump,
    no_add_queue,
    NULL,  /* should never get called */
    NULL,  /* should never get called */
    NULL,  /* should never get called */
    no_read_fd,
    no_write_fd,
    no_flush,
    no_get_file_info,
    key_destroy
};


/*
 * The registry text file format v2 used by this code is similar to the one
 * used by REGEDIT import/export functionality, with the following differences:
 * - strings and key names can contain \x escapes for Unicode
 * - key names use escapes too in order to support Unicode
 * - the modification time optionally follows the key name
 * - REG_EXPAND_SZ and REG_MULTI_SZ are saved as strings instead of hex
 */

/* dump a string to a text file with proper escaping */
static int dump_strW( const WCHAR *str, int len, FILE *f, char escape[2] )
{
    static const char escapes[32] = ".......abtnvfr.............e....";
    char buffer[256];
    char *pos = buffer;
    int count = 0;

    for (; len; str++, len--)
    {
        if (pos > buffer + sizeof(buffer) - 8)
        {
            fwrite( buffer, pos - buffer, 1, f );
            count += pos - buffer;
            pos = buffer;
        }
        if (*str > 127)  /* hex escape */
        {
            if (len > 1 && str[1] < 128 && isxdigit((char)str[1]))
                pos += sprintf( pos, "\\x%04x", *str );
            else
                pos += sprintf( pos, "\\x%x", *str );
            continue;
        }
        if (*str < 32)  /* octal or C escape */
        {
            if (!*str && len == 1) continue;  /* do not output terminating NULL */
            if (escapes[*str] != '.')
                pos += sprintf( pos, "\\%c", escapes[*str] );
            else if (len > 1 && str[1] >= '0' && str[1] <= '7')
                pos += sprintf( pos, "\\%03o", *str );
            else
                pos += sprintf( pos, "\\%o", *str );
            continue;
        }
        if (*str == '\\' || *str == escape[0] || *str == escape[1]) *pos++ = '\\';
        *pos++ = *str;
    }
    fwrite( buffer, pos - buffer, 1, f );
    count += pos - buffer;
    return count;
}


static inline char to_hex( char ch )
{
    if (isdigit(ch)) return ch - '0';
    return tolower(ch) - 'a' + 10;
}

/* dump the full path of a key */
static void dump_path( struct key *key, FILE *f )
{
    if (key->parent) dump_path( key->parent, f );
    else if (key->name) fprintf( f, "?????" );

    if (key->name)
    {
        fprintf( f, "\\\\" );
        dump_strW( key->name, strlenW(key->name), f, "[]" );
    }
    else  /* root key */
    {
        int i;
        for (i = 0; i < NB_ROOT_KEYS; i++)
            if (root_keys[i] == key) fprintf( f, "%s", root_key_names[i] );
    }
}

/* dump a value to a text file */
static void dump_value( struct key_value *value, FILE *f )
{
    int i, count;

    if (value->name[0])
    {
        fputc( '\"', f );
        count = 1 + dump_strW( value->name, strlenW(value->name), f, "\"\"" );
        count += fprintf( f, "\"=" );
    }
    else count = fprintf( f, "@=" );

    switch(value->type)
    {
    case REG_SZ:
    case REG_EXPAND_SZ:
    case REG_MULTI_SZ:
        if (value->type != REG_SZ) fprintf( f, "str(%d):", value->type );
        fputc( '\"', f );
        if (value->data) dump_strW( (WCHAR *)value->data, value->len / sizeof(WCHAR), f, "\"\"" );
        fputc( '\"', f );
        break;
    case REG_DWORD:
        if (value->len == sizeof(DWORD))
        {
            DWORD dw;
            memcpy( &dw, value->data, sizeof(DWORD) );
            fprintf( f, "dword:%08lx", dw );
            break;
        }
        /* else fall through */
    default:
        if (value->type == REG_BINARY) count += fprintf( f, "hex:" );
        else count += fprintf( f, "hex(%x):", value->type );
        for (i = 0; i < value->len; i++)
        {
            count += fprintf( f, "%02x", *((unsigned char *)value->data + i) );
            if (i < value->len-1)
            {
                fputc( ',', f );
                if (++count > 76)
                {
                    fprintf( f, "\\\n  " );
                    count = 2;
                }
            }
        }
        break;
    }
    fputc( '\n', f );
}

/* save a registry and all its subkeys to a text file */
static void save_subkeys( struct key *key, FILE *f )
{
    int i;

    if (key->flags & KEY_VOLATILE) return;
    /* save key if it has the proper level, and has either some values or no subkeys */
    /* keys with no values but subkeys are saved implicitly by saving the subkeys */
    if ((key->level >= saving_level) && ((key->last_value >= 0) || (key->last_subkey == -1)))
    {
        fprintf( f, "\n[" );
        dump_path( key, f );
        fprintf( f, "] %ld\n", key->modif );
        for (i = 0; i <= key->last_value; i++) dump_value( &key->values[i], f );
    }
    for (i = 0; i <= key->last_subkey; i++) save_subkeys( key->subkeys[i], f );
}

static void dump_operation( struct key *key, struct key_value *value, const char *op )
{
    fprintf( stderr, "%s key ", op );
    if (key) dump_path( key, stderr );
    else fprintf( stderr, "ERROR" );
    if (value)
    {
        fprintf( stderr, " value ");
        dump_value( value, stderr );
    }
    else fprintf( stderr, "\n" );
}

static void key_dump( struct object *obj, int verbose )
{
    struct key *key = (struct key *)obj;
    assert( obj->ops == &key_ops );
    fprintf( stderr, "Key flags=%x ", key->flags );
    dump_path( key, stderr );
    fprintf( stderr, "\n" );
}

static void key_destroy( struct object *obj )
{
    int i;
    struct key *key = (struct key *)obj;
    assert( obj->ops == &key_ops );

    free( key->name );
    if (key->class) free( key->class );
    for (i = 0; i <= key->last_value; i++)
    {
        free( key->values[i].name );
        if (key->values[i].data) free( key->values[i].data );
    }
    for (i = 0; i <= key->last_subkey; i++) release_object( key->subkeys[i] );
}

/* duplicate a key path from the request buffer */
/* returns a pointer to a static buffer, so only useable once per request */
static WCHAR *copy_path( const path_t path )
{
    static WCHAR buffer[MAX_PATH+1];
    WCHAR *p = buffer;

    while (p < buffer + sizeof(buffer) - 1) if (!(*p++ = *path++)) break;
    *p = 0;
    return buffer;
}

/* return the next token in a given path */
/* returns a pointer to a static buffer, so only useable once per request */
static WCHAR *get_path_token( const WCHAR *initpath, size_t maxlen )
{
    static const WCHAR *path;
    static const WCHAR *end;
    static WCHAR buffer[MAX_PATH+1];
    WCHAR *p = buffer;

    if (initpath)
    {
        path = initpath;
        end  = path + maxlen / sizeof(WCHAR);
    }
    while ((path < end) && (*path == '\\')) path++;
    while ((path < end) && (p < buffer + sizeof(buffer) - 1))
    {
        WCHAR ch = *path;
        if (!ch || (ch == '\\')) break;
        *p++ = ch;
        path++;
    }
    *p = 0;
    return buffer;
}

/* duplicate a Unicode string from the request buffer */
static WCHAR *req_strdupW( const WCHAR *str )
{
    WCHAR *name;
    size_t len = get_req_strlenW( str );
    if ((name = mem_alloc( (len + 1) * sizeof(WCHAR) )) != NULL)
    {
        memcpy( name, str, len * sizeof(WCHAR) );
        name[len] = 0;
    }
    return name;
}

/* allocate a key object */
static struct key *alloc_key( const WCHAR *name, time_t modif )
{
    struct key *key;
    if ((key = (struct key *)alloc_object( &key_ops )))
    {
        key->name        = NULL;
        key->class       = NULL;
        key->flags       = 0;
        key->last_subkey = -1;
        key->nb_subkeys  = 0;
        key->subkeys     = NULL;
        key->nb_values   = 0;
        key->last_value  = -1;
        key->values      = NULL;
        key->level       = current_level;
        key->modif       = modif;
        key->parent      = NULL;
        if (name && !(key->name = strdupW( name )))
        {
            release_object( key );
            key = NULL;
        }
    }
    return key;
}

/* update key modification time */
static void touch_key( struct key *key )
{
    key->modif = time(NULL);
    key->level = MAX( key->level, current_level );
}

/* try to grow the array of subkeys; return 1 if OK, 0 on error */
static int grow_subkeys( struct key *key )
{
    struct key **new_subkeys;
    int nb_subkeys;

    if (key->nb_subkeys)
    {
        nb_subkeys = key->nb_subkeys + (key->nb_subkeys / 2);  /* grow by 50% */
        if (!(new_subkeys = realloc( key->subkeys, nb_subkeys * sizeof(*new_subkeys) )))
        {
            set_error( ERROR_OUTOFMEMORY );
            return 0;
        }
    }
    else
    {
        nb_subkeys = MIN_VALUES;
        if (!(new_subkeys = mem_alloc( nb_subkeys * sizeof(*new_subkeys) ))) return 0;
    }
    key->subkeys    = new_subkeys;
    key->nb_subkeys = nb_subkeys;
    return 1;
}

/* allocate a subkey for a given key, and return its index */
static struct key *alloc_subkey( struct key *parent, const WCHAR *name, int index, time_t modif )
{
    struct key *key;
    int i;

    if (parent->last_subkey + 1 == parent->nb_subkeys)
    {
        /* need to grow the array */
        if (!grow_subkeys( parent )) return NULL;
    }
    if ((key = alloc_key( name, modif )) != NULL)
    {
        key->parent = parent;
        for (i = ++parent->last_subkey; i > index; i--)
            parent->subkeys[i] = parent->subkeys[i-1];
        parent->subkeys[index] = key;
    }
    return key;
}

/* free a subkey of a given key */
static void free_subkey( struct key *parent, int index )
{
    struct key *key;
    int i, nb_subkeys;

    assert( index >= 0 );
    assert( index <= parent->last_subkey );

    key = parent->subkeys[index];
    for (i = index; i < parent->last_subkey; i++) parent->subkeys[i] = parent->subkeys[i + 1];
    parent->last_subkey--;
    key->flags |= KEY_DELETED;
    key->parent = NULL;
    release_object( key );
    
    /* try to shrink the array */
    nb_subkeys = key->nb_subkeys;
    if (nb_subkeys > MIN_SUBKEYS && key->last_subkey < nb_subkeys / 2)
    {
        struct key **new_subkeys;
        nb_subkeys -= nb_subkeys / 3;  /* shrink by 33% */
        if (nb_subkeys < MIN_SUBKEYS) nb_subkeys = MIN_SUBKEYS;
        if (!(new_subkeys = realloc( key->subkeys, nb_subkeys * sizeof(*new_subkeys) ))) return;
        key->subkeys = new_subkeys;
        key->nb_subkeys = nb_subkeys;
    }
}

/* find the named child of a given key and return its index */
static struct key *find_subkey( struct key *key, const WCHAR *name, int *index )
{
    int i, min, max, res;

    min = 0;
    max = key->last_subkey;
    while (min <= max)
    {
        i = (min + max) / 2;
        if (!(res = strcmpiW( key->subkeys[i]->name, name )))
        {
            *index = i;
            return key->subkeys[i];
        }
        if (res > 0) max = i - 1;
        else min = i + 1;
    }
    *index = min;  /* this is where we should insert it */
    return NULL;
}

/* open a subkey */
static struct key *open_key( struct key *key, const WCHAR *name, size_t maxlen )
{
    int index;
    WCHAR *path;

    path = get_path_token( name, maxlen );
    while (*path)
    {
        if (!(key = find_subkey( key, path, &index )))
        {
            set_error( ERROR_FILE_NOT_FOUND );
            break;
        }
        path = get_path_token( NULL, 0 );
    }

    if (debug_level > 1) dump_operation( key, NULL, "Open" );
    if (key) grab_object( key );
    return key;
}

/* create a subkey */
static struct key *create_key( struct key *key, const WCHAR *name, size_t maxlen, WCHAR *class,
                               unsigned int options, time_t modif, int *created )
{
    struct key *base;
    int base_idx, index, flags = 0;
    WCHAR *path;

    if (key->flags & KEY_DELETED) /* we cannot create a subkey under a deleted key */
    {
        set_error( ERROR_KEY_DELETED );
        return NULL;
    }
    if (options & REG_OPTION_VOLATILE) flags |= KEY_VOLATILE;
    else if (key->flags & KEY_VOLATILE)
    {
        set_error( ERROR_CHILD_MUST_BE_VOLATILE );
        return NULL;
    }

    path = get_path_token( name, maxlen );
    *created = 0;
    while (*path)
    {
        struct key *subkey;
        if (!(subkey = find_subkey( key, path, &index ))) break;
        key = subkey;
        path = get_path_token( NULL, 0 );
    }

    /* create the remaining part */

    if (!*path) goto done;
    *created = 1;
    base = key;
    base_idx = index;
    key = alloc_subkey( key, path, index, modif );
    while (key)
    {
        key->flags |= flags;
        path = get_path_token( NULL, 0 );
        if (!*path) goto done;
        /* we know the index is always 0 in a new key */
        key = alloc_subkey( key, path, 0, modif );
    }
    if (base_idx != -1) free_subkey( base, base_idx );
    return NULL;

 done:
    if (debug_level > 1) dump_operation( key, NULL, "Create" );
    if (class) key->class = strdupW(class);
    grab_object( key );
    return key;
}

/* find a subkey of a given key by its index */
static void enum_key( struct key *parent, int index, WCHAR *name, WCHAR *class, time_t *modif )
{
    struct key *key;

    if ((index < 0) || (index > parent->last_subkey)) set_error( ERROR_NO_MORE_ITEMS );
    else
    {
        key = parent->subkeys[index];
        *modif = key->modif;
        strcpyW( name, key->name );
        if (key->class) strcpyW( class, key->class );  /* FIXME: length */
        else *class = 0;
        if (debug_level > 1) dump_operation( key, NULL, "Enum" );
    }
}

/* query information about a key */
static void query_key( struct key *key, struct query_key_info_request *req )
{
    int i, len;
    int max_subkey = 0, max_class = 0;
    int max_value = 0, max_data = 0;

    for (i = 0; i < key->last_subkey; i++)
    {
        struct key *subkey = key->subkeys[i];
        len = strlenW( subkey->name );
        if (len > max_subkey) max_subkey = len;
        if (!subkey->class) continue;
        len = strlenW( subkey->class );
        if (len > max_class) max_class = len;
    }
    for (i = 0; i < key->last_value; i++)
    {
        len = strlenW( key->values[i].name );
        if (len > max_value) max_value = len;
        len = key->values[i].len;
        if (len > max_data) max_data = len;
    }
    req->subkeys    = key->last_subkey + 1;
    req->max_subkey = max_subkey;
    req->max_class  = max_class;
    req->values     = key->last_value + 1;
    req->max_value  = max_value;
    req->max_data   = max_data;
    req->modif      = key->modif;
    if (key->class) strcpyW( req->class, key->class );  /* FIXME: length */
    else req->class[0] = 0;
    if (debug_level > 1) dump_operation( key, NULL, "Query" );
}

/* delete a key and its values */
static void delete_key( struct key *key, const WCHAR *name, size_t maxlen )
{
    int index;
    struct key *parent;
    WCHAR *path;

    path = get_path_token( name, maxlen );
    if (!*path)
    {
        /* deleting this key, must find parent and index */
        if (key->flags & KEY_ROOT)
        {
            set_error( ERROR_ACCESS_DENIED );
            return;
        }
        if (!(parent = key->parent) || (key->flags & KEY_DELETED))
        {
            set_error( ERROR_KEY_DELETED );
            return;
        }
        for (index = 0; index <= parent->last_subkey; index++)
            if (parent->subkeys[index] == key) break;
        assert( index <= parent->last_subkey );
    }
    else while (*path)
    {
        parent = key;
        if (!(key = find_subkey( parent, path, &index )))
        {
            set_error( ERROR_FILE_NOT_FOUND );
            return;
        }
        path = get_path_token( NULL, 0 );
    }

    /* we can only delete a key that has no subkeys (FIXME) */
    if ((key->flags & KEY_ROOT) || (key->last_subkey >= 0))
    {
        set_error( ERROR_ACCESS_DENIED );
        return;
    }
    if (debug_level > 1) dump_operation( key, NULL, "Delete" );
    free_subkey( parent, index );
    touch_key( parent );
}

/* try to grow the array of values; return 1 if OK, 0 on error */
static int grow_values( struct key *key )
{
    struct key_value *new_val;
    int nb_values;

    if (key->nb_values)
    {
        nb_values = key->nb_values + (key->nb_values / 2);  /* grow by 50% */
        if (!(new_val = realloc( key->values, nb_values * sizeof(*new_val) )))
        {
            set_error( ERROR_OUTOFMEMORY );
            return 0;
        }
    }
    else
    {
        nb_values = MIN_VALUES;
        if (!(new_val = mem_alloc( nb_values * sizeof(*new_val) ))) return 0;
    }
    key->values = new_val;
    key->nb_values = nb_values;
    return 1;
}

/* find the named value of a given key and return its index in the array */
static struct key_value *find_value( const struct key *key, const WCHAR *name, int *index )
{
    int i, min, max, res;

    min = 0;
    max = key->last_value;
    while (min <= max)
    {
        i = (min + max) / 2;
        if (!(res = strcmpiW( key->values[i].name, name )))
        {
            *index = i;
            return &key->values[i];
        }
        if (res > 0) max = i - 1;
        else min = i + 1;
    }
    *index = min;  /* this is where we should insert it */
    return NULL;
}

/* insert a new value or return a pointer to an existing one */
static struct key_value *insert_value( struct key *key, const WCHAR *name )
{
    struct key_value *value;
    WCHAR *new_name;
    int i, index;

    if (!(value = find_value( key, name, &index )))
    {
        /* not found, add it */
        if (key->last_value + 1 == key->nb_values)
        {
            if (!grow_values( key )) return NULL;
        }
        if (!(new_name = strdupW(name))) return NULL;
        for (i = ++key->last_value; i > index; i--) key->values[i] = key->values[i - 1];
        value = &key->values[index];
        value->name = new_name;
        value->len  = 0;
        value->data = NULL;
    }
    return value;
}

/* set a key value */
static void set_value( struct key *key, WCHAR *name, int type, int datalen, void *data )
{
    struct key_value *value;
    void *ptr = NULL;
    
    /* first copy the data */
    if (datalen)
    {
        if (!(ptr = mem_alloc( datalen ))) return;
        memcpy( ptr, data, datalen );
    }

    if (!(value = insert_value( key, name )))
    {
        if (ptr) free( ptr );
        return;
    }
    if (value->data) free( value->data ); /* already existing, free previous data */
    value->type  = type;
    value->len   = datalen;
    value->data  = ptr;
    touch_key( key );
    if (debug_level > 1) dump_operation( key, value, "Set" );
}

/* get a key value */
static void get_value( struct key *key, WCHAR *name, int *type, int *len, void *data )
{
    struct key_value *value;
    int index;

    if ((value = find_value( key, name, &index )))
    {
        *type = value->type;
        *len  = value->len;
        if (value->data) memcpy( data, value->data, value->len );
        if (debug_level > 1) dump_operation( key, value, "Get" );
    }
    else
    {
        *type = -1;
        *len = 0;
        set_error( ERROR_FILE_NOT_FOUND );
    }
}

/* enumerate a key value */
static void enum_value( struct key *key, int i, WCHAR *name, int *type, int *len, void *data )
{
    struct key_value *value;

    if (i < 0 || i > key->last_value)
    {
        name[0] = 0;
        *len = 0;
        set_error( ERROR_NO_MORE_ITEMS );
    }
    else
    {
        value = &key->values[i];
        strcpyW( name, value->name );
        *type = value->type;
        *len  = value->len;
        if (value->data) memcpy( data, value->data, value->len );
        if (debug_level > 1) dump_operation( key, value, "Enum" );
    }
}

/* delete a value */
static void delete_value( struct key *key, const WCHAR *name )
{
    struct key_value *value;
    int i, index, nb_values;

    if (!(value = find_value( key, name, &index )))
    {
        set_error( ERROR_FILE_NOT_FOUND );
        return;
    }
    if (debug_level > 1) dump_operation( key, value, "Delete" );
    free( value->name );
    if (value->data) free( value->data );
    for (i = index; i < key->last_value; i++) key->values[i] = key->values[i + 1];
    key->last_value--;
    touch_key( key );

    /* try to shrink the array */
    nb_values = key->nb_values;
    if (nb_values > MIN_VALUES && key->last_value < nb_values / 2)
    {
        struct key_value *new_val;
        nb_values -= nb_values / 3;  /* shrink by 33% */
        if (nb_values < MIN_VALUES) nb_values = MIN_VALUES;
        if (!(new_val = realloc( key->values, nb_values * sizeof(*new_val) ))) return;
        key->values = new_val;
        key->nb_values = nb_values;
    }
}    

static struct key *get_hkey_obj( int hkey, unsigned int access );

static struct key *create_root_key( int hkey )
{
    int dummy;
    struct key *key;

    switch(hkey)
    {
    case HKEY_CLASSES_ROOT:
        {
            static const WCHAR name[] =
                          { 'S','O','F','T','W','A','R','E','\\','C','l','a','s','s','e','s',0 };

            struct key *root = get_hkey_obj( HKEY_LOCAL_MACHINE, 0 );
            if (!root) return NULL;
            key = create_key( root, name, sizeof(name), NULL, 0, time(NULL), &dummy );
            release_object( root );
        }
        break;
    case HKEY_CURRENT_USER: /* FIXME: should be HKEY_USERS\\the_current_user_SID */
    case HKEY_LOCAL_MACHINE:
    case HKEY_USERS:
    case HKEY_PERFORMANCE_DATA:
    case HKEY_DYN_DATA:
    case HKEY_CURRENT_CONFIG:
        key = alloc_key( NULL, time(NULL) );
        break;
    default:
        key = NULL;
        assert(0);
    }
    if (key)
    {
        root_keys[hkey - HKEY_ROOT_FIRST] = key;
        key->flags |= KEY_ROOT;
    }
    return key;
}

/* close the top-level keys; used on server exit */
void close_registry(void)
{
    int i;
    for (i = 0; i < NB_ROOT_KEYS; i++)
    {
        if (root_keys[i] && !root_keys[i]->parent) release_object( root_keys[i] );
    }
}

/* get the registry key corresponding to an hkey handle */
static struct key *get_hkey_obj( int hkey, unsigned int access )
{
    struct key *key;

    if (IS_ROOT_HKEY(hkey))
    {
        if (!(key = root_keys[hkey - HKEY_ROOT_FIRST])) key = create_root_key( hkey );
        grab_object( key );
    }
    else
        key = (struct key *)get_handle_obj( current->process, hkey, access, &key_ops );
    return key;
}

/* update the level of the parents of a key (only needed for the old format) */
static int update_level( struct key *key )
{
    int i;
    int max = key->level;
    for (i = 0; i <= key->last_subkey; i++)
    {
        int sub = update_level( key->subkeys[i] );
        if (sub > max) max = sub;
    }
    key->level = max;
    return max;
}

/* dump a string to a registry save file in the old v1 format */
static void save_string_v1( LPCWSTR str, FILE *f )
{
    if (!str) return;
    while (*str)
    {
        if ((*str > 0x7f) || (*str == '\n') || (*str == '='))
            fprintf( f, "\\u%04x", *str );
        else
        {
            if (*str == '\\') fputc( '\\', f );
            fputc( (char)*str, f );
        }
        str++;
    }
}

/* save a registry and all its subkeys to a text file in the old v1 format */
static void save_subkeys_v1( struct key *key, int nesting, FILE *f )
{
    int i, j;

    if (key->flags & KEY_VOLATILE) return;
    if (key->level < saving_level) return;
    for (i = 0; i <= key->last_value; i++)
    {
        struct key_value *value = &key->values[i];
        for (j = nesting; j > 0; j --) fputc( '\t', f );
        save_string_v1( value->name, f );
        fprintf( f, "=%d,%d,", value->type, 0 );
        if (value->type == REG_SZ || value->type == REG_EXPAND_SZ)
            save_string_v1( (LPWSTR)value->data, f );
        else
            for (j = 0; j < value->len; j++)
                fprintf( f, "%02x", *((unsigned char *)value->data + j) );
        fputc( '\n', f );
    }
    for (i = 0; i <= key->last_subkey; i++)
    {
        for (j = nesting; j > 0; j --) fputc( '\t', f );
        save_string_v1( key->subkeys[i]->name, f );
        fputc( '\n', f );
        save_subkeys_v1( key->subkeys[i], nesting + 1, f );
    }
}

/* save a registry branch to a file handle */
static void save_registry( struct key *key, int handle )
{
    struct object *obj;
    int fd;

    if (key->flags & KEY_DELETED)
    {
        set_error( ERROR_KEY_DELETED );
        return;
    }
    if (!(obj = get_handle_obj( current->process, handle, GENERIC_WRITE, NULL ))) return;
    fd = obj->ops->get_write_fd( obj );
    release_object( obj );
    if (fd != -1)
    {
        FILE *f = fdopen( fd, "w" );
        if (f)
        {
            fprintf( f, "WINE REGISTRY Version %d\n", saving_version );
            if (saving_version == 2) save_subkeys( key, f );
            else
            {
                update_level( key );
                save_subkeys_v1( key, 0, f );
            }
            if (fclose( f )) file_set_error();
        }
        else
        {
            file_set_error();
            close( fd );
        }
    }
}

/* create a registry key */
DECL_HANDLER(create_key)
{
    struct key *key, *parent;
    WCHAR *class;
    unsigned int access = req->access;

    if (access & MAXIMUM_ALLOWED) access = KEY_ALL_ACCESS;  /* FIXME: needs general solution */
    req->hkey = -1;
    if ((parent = get_hkey_obj( req->parent, KEY_CREATE_SUB_KEY )))
    {
        if ((class = req_strdupW( req->class )))
        {
            if ((key = create_key( parent, req->name, sizeof(req->name), class, req->options,
                                   req->modif, &req->created )))
            {
                req->hkey = alloc_handle( current->process, key, access, 0 );
                release_object( key );
            }
            free( class );
        }
        release_object( parent );
    }
}

/* open a registry key */
DECL_HANDLER(open_key)
{
    struct key *key, *parent;
    unsigned int access = req->access;

    if (access & MAXIMUM_ALLOWED) access = KEY_ALL_ACCESS;  /* FIXME: needs general solution */
    req->hkey = -1;
    if ((parent = get_hkey_obj( req->parent, 0 /*FIXME*/ )))
    {
        if ((key = open_key( parent, req->name, sizeof(req->name) )))
        {
            req->hkey = alloc_handle( current->process, key, access, 0 );
            release_object( key );
        }
        release_object( parent );
    }
}

/* delete a registry key */
DECL_HANDLER(delete_key)
{
    struct key *key;

    if ((key = get_hkey_obj( req->hkey, KEY_CREATE_SUB_KEY /*FIXME*/ )))
    {
        delete_key( key, req->name, sizeof(req->name) );
        release_object( key );
    }
}

/* close a registry key */
DECL_HANDLER(close_key)
{
    int hkey = req->hkey;
    /* ignore attempts to close a root key */
    if (!IS_ROOT_HKEY(hkey)) close_handle( current->process, hkey );
}

/* enumerate registry subkeys */
DECL_HANDLER(enum_key)
{
    struct key *key;

    if ((key = get_hkey_obj( req->hkey, KEY_ENUMERATE_SUB_KEYS )))
    {
        enum_key( key, req->index, req->name, req->class, &req->modif );
        release_object( key );
    }
}

/* query information about a registry key */
DECL_HANDLER(query_key_info)
{
    struct key *key;

    if ((key = get_hkey_obj( req->hkey, KEY_QUERY_VALUE )))
    {
        query_key( key, req );
        release_object( key );
    }
}

/* set a value of a registry key */
DECL_HANDLER(set_key_value)
{
    struct key *key;
    int max = get_req_size( req->data, sizeof(req->data[0]) );
    int datalen = req->len;
    if (datalen > max)
    {
        set_error( ERROR_OUTOFMEMORY );  /* FIXME */
        return;
    }
    if ((key = get_hkey_obj( req->hkey, KEY_SET_VALUE )))
    {
        set_value( key, copy_path( req->name ), req->type, datalen, req->data );
        release_object( key );
    }
}

/* retrieve the value of a registry key */
DECL_HANDLER(get_key_value)
{
    struct key *key;

    if ((key = get_hkey_obj( req->hkey, KEY_QUERY_VALUE )))
    {
        get_value( key, copy_path( req->name ), &req->type, &req->len, req->data );
        release_object( key );
    }
}

/* enumerate the value of a registry key */
DECL_HANDLER(enum_key_value)
{
    struct key *key;

    if ((key = get_hkey_obj( req->hkey, KEY_QUERY_VALUE )))
    {
        enum_value( key, req->index, req->name, &req->type, &req->len, req->data );
        release_object( key );
    }
}

/* delete a value of a registry key */
DECL_HANDLER(delete_key_value)
{
    WCHAR *name;
    struct key *key;

    if ((key = get_hkey_obj( req->hkey, KEY_SET_VALUE )))
    {
        if ((name = req_strdupW( req->name )))
        {
            delete_value( key, name );
            free( name );
        }
        release_object( key );
    }
}

/* load a registry branch from a file */
DECL_HANDLER(load_registry)
{
    struct key *key;

    if ((key = get_hkey_obj( req->hkey, KEY_SET_VALUE | KEY_CREATE_SUB_KEY )))
    {
        set_error( ERROR_CALL_NOT_IMPLEMENTED );
        release_object( key );
    }
}

/* save a registry branch to a file */
DECL_HANDLER(save_registry)
{
    struct key *key;

    if ((key = get_hkey_obj( req->hkey, KEY_QUERY_VALUE | KEY_ENUMERATE_SUB_KEYS )))
    {
        save_registry( key, req->file );
        release_object( key );
    }
}

/* set the current and saving level for the registry */
DECL_HANDLER(set_registry_levels)
{
    current_level  = req->current;
    saving_level   = req->saving;
}