442 lines
13 KiB
C
442 lines
13 KiB
C
/*
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* Server-side handle management
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*
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* Copyright (C) 1998 Alexandre Julliard
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*/
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#include <assert.h>
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#include <limits.h>
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#include <string.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include "winerror.h"
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#include "winbase.h"
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#include "handle.h"
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#include "process.h"
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#include "thread.h"
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#include "request.h"
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struct handle_entry
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{
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struct object *ptr;
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unsigned int access;
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};
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struct handle_table
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{
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struct object obj; /* object header */
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struct process *process; /* process owning this table */
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int count; /* number of allocated entries */
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int last; /* last used entry */
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int free; /* first entry that may be free */
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struct handle_entry *entries; /* handle entries */
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};
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static struct handle_table *global_table;
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/* reserved handle access rights */
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#define RESERVED_SHIFT 25
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#define RESERVED_INHERIT (HANDLE_FLAG_INHERIT << RESERVED_SHIFT)
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#define RESERVED_CLOSE_PROTECT (HANDLE_FLAG_PROTECT_FROM_CLOSE << RESERVED_SHIFT)
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#define RESERVED_ALL (RESERVED_INHERIT | RESERVED_CLOSE_PROTECT)
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/* global handle macros */
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#define HANDLE_OBFUSCATOR 0x544a4def
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#define HANDLE_IS_GLOBAL(h) (((h) ^ HANDLE_OBFUSCATOR) < 0x10000)
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#define HANDLE_LOCAL_TO_GLOBAL(h) ((h) ^ HANDLE_OBFUSCATOR)
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#define HANDLE_GLOBAL_TO_LOCAL(h) ((h) ^ HANDLE_OBFUSCATOR)
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#define MIN_HANDLE_ENTRIES 32
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static void handle_table_dump( struct object *obj, int verbose );
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static void handle_table_destroy( struct object *obj );
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static const struct object_ops handle_table_ops =
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{
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sizeof(struct handle_table),
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handle_table_dump,
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no_add_queue,
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NULL, /* should never get called */
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NULL, /* should never get called */
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NULL, /* should never get called */
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no_read_fd,
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no_write_fd,
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no_flush,
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no_get_file_info,
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handle_table_destroy
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};
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/* dump a handle table */
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static void handle_table_dump( struct object *obj, int verbose )
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{
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int i;
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struct handle_table *table = (struct handle_table *)obj;
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struct handle_entry *entry = table->entries;
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assert( obj->ops == &handle_table_ops );
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fprintf( stderr, "Handle table last=%d count=%d process=%p\n",
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table->last, table->count, table->process );
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if (!verbose) return;
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entry = table->entries;
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for (i = 0; i <= table->last; i++, entry++)
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{
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if (!entry->ptr) continue;
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fprintf( stderr, "%9d: %p %08x ", i + 1, entry->ptr, entry->access );
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entry->ptr->ops->dump( entry->ptr, 0 );
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}
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}
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/* destroy a handle table */
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static void handle_table_destroy( struct object *obj )
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{
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int i;
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struct handle_table *table = (struct handle_table *)obj;
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struct handle_entry *entry = table->entries;
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assert( obj->ops == &handle_table_ops );
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for (i = 0; i <= table->last; i++, entry++)
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{
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struct object *obj = entry->ptr;
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entry->ptr = NULL;
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if (obj) release_object( obj );
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}
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free( table->entries );
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}
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/* allocate a new handle table */
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struct object *alloc_handle_table( struct process *process, int count )
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{
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struct handle_table *table;
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if (count < MIN_HANDLE_ENTRIES) count = MIN_HANDLE_ENTRIES;
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if (!(table = alloc_object( &handle_table_ops )))
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return NULL;
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table->process = process;
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table->count = count;
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table->last = -1;
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table->free = 0;
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if ((table->entries = mem_alloc( count * sizeof(*table->entries) ))) return &table->obj;
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release_object( table );
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return NULL;
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}
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/* grow a handle table */
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static int grow_handle_table( struct handle_table *table )
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{
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struct handle_entry *new_entries;
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int count = table->count;
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if (count >= INT_MAX / 2) return 0;
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count *= 2;
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if (!(new_entries = realloc( table->entries, count * sizeof(struct handle_entry) )))
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{
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set_error( ERROR_OUTOFMEMORY );
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return 0;
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}
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table->entries = new_entries;
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table->count = count;
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return 1;
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}
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/* find the first free entry in the handle table */
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static struct handle_entry *get_free_entry( struct handle_table *table, int *phandle )
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{
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struct handle_entry *entry = table->entries + table->free;
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int handle;
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for (handle = table->free; handle <= table->last; handle++, entry++)
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if (!entry->ptr) goto found;
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if (handle >= table->count)
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{
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if (!grow_handle_table( table )) return NULL;
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entry = table->entries + handle; /* the entries may have moved */
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}
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table->last = handle;
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found:
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table->free = *phandle = handle + 1; /* avoid handle 0 */
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return entry;
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}
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/* allocate a handle for an object, incrementing its refcount */
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/* return the handle, or -1 on error */
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int alloc_handle( struct process *process, void *obj, unsigned int access, int inherit )
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{
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struct handle_table *table = (struct handle_table *)process->handles;
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struct handle_entry *entry;
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int handle;
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assert( table );
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assert( !(access & RESERVED_ALL) );
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if (inherit) access |= RESERVED_INHERIT;
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if (!(entry = get_free_entry( table, &handle ))) return -1;
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entry->ptr = grab_object( obj );
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entry->access = access;
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return handle;
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}
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/* allocate a global handle for an object, incrementing its refcount */
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/* return the handle, or -1 on error */
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static int alloc_global_handle( void *obj, unsigned int access )
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{
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struct handle_entry *entry;
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int handle;
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if (!global_table)
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{
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if (!(global_table = (struct handle_table *)alloc_handle_table( NULL, 0 ))) return -1;
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}
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if (!(entry = get_free_entry( global_table, &handle ))) return -1;
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entry->ptr = grab_object( obj );
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entry->access = access;
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return HANDLE_LOCAL_TO_GLOBAL(handle);
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}
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/* return an handle entry, or NULL if the handle is invalid */
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static struct handle_entry *get_handle( struct process *process, int handle )
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{
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struct handle_table *table = (struct handle_table *)process->handles;
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struct handle_entry *entry;
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if (HANDLE_IS_GLOBAL(handle))
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{
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handle = HANDLE_GLOBAL_TO_LOCAL(handle);
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table = global_table;
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}
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if (!table) goto error;
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handle--; /* handles start at 1 */
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if (handle < 0) goto error;
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if (handle > table->last) goto error;
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entry = table->entries + handle;
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if (!entry->ptr) goto error;
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return entry;
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error:
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set_error( ERROR_INVALID_HANDLE );
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return NULL;
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}
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/* attempt to shrink a table */
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static void shrink_handle_table( struct handle_table *table )
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{
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struct handle_entry *entry = table->entries + table->last;
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struct handle_entry *new_entries;
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int count = table->count;
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while (table->last >= 0)
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{
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if (entry->ptr) break;
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table->last--;
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entry--;
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}
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if (table->last >= count / 4) return; /* no need to shrink */
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if (count < MIN_HANDLE_ENTRIES * 2) return; /* too small to shrink */
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count /= 2;
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if (!(new_entries = realloc( table->entries, count * sizeof(*new_entries) ))) return;
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table->count = count;
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table->entries = new_entries;
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}
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/* copy the handle table of the parent process */
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/* return 1 if OK, 0 on error */
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struct object *copy_handle_table( struct process *process, struct process *parent )
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{
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struct handle_table *parent_table = (struct handle_table *)parent->handles;
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struct handle_table *table;
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int i;
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assert( parent_table );
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assert( parent_table->obj.ops == &handle_table_ops );
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if (!(table = (struct handle_table *)alloc_handle_table( process, parent_table->count )))
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return NULL;
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if ((table->last = parent_table->last) >= 0)
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{
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struct handle_entry *ptr = table->entries;
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memcpy( ptr, parent_table->entries, (table->last + 1) * sizeof(struct handle_entry) );
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for (i = 0; i <= table->last; i++, ptr++)
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{
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if (!ptr->ptr) continue;
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if (ptr->access & RESERVED_INHERIT) grab_object( ptr->ptr );
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else ptr->ptr = NULL; /* don't inherit this entry */
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}
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}
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/* attempt to shrink the table */
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shrink_handle_table( table );
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return &table->obj;
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}
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/* close a handle and decrement the refcount of the associated object */
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/* return 1 if OK, 0 on error */
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int close_handle( struct process *process, int handle )
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{
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struct handle_table *table;
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struct handle_entry *entry;
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struct object *obj;
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if (!(entry = get_handle( process, handle ))) return 0;
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if (entry->access & RESERVED_CLOSE_PROTECT) return 0; /* FIXME: error code */
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obj = entry->ptr;
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entry->ptr = NULL;
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table = HANDLE_IS_GLOBAL(handle) ? global_table : (struct handle_table *)process->handles;
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if (entry < table->entries + table->free) table->free = entry - table->entries;
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if (entry == table->entries + table->last) shrink_handle_table( table );
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release_object( obj );
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return 1;
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}
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/* close all the global handles */
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void close_global_handles(void)
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{
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if (global_table)
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{
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release_object( global_table );
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global_table = NULL;
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}
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}
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/* retrieve the object corresponding to a handle, incrementing its refcount */
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struct object *get_handle_obj( struct process *process, int handle,
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unsigned int access, const struct object_ops *ops )
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{
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struct handle_entry *entry;
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struct object *obj;
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switch( handle )
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{
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case 0xfffffffe: /* current thread pseudo-handle */
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obj = ¤t->obj;
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break;
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case 0x7fffffff: /* current process pseudo-handle */
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obj = (struct object *)current->process;
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break;
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default:
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if (!(entry = get_handle( process, handle ))) return NULL;
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if ((entry->access & access) != access)
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{
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set_error( ERROR_ACCESS_DENIED );
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return NULL;
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}
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obj = entry->ptr;
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break;
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}
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if (ops && (obj->ops != ops))
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{
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set_error( ERROR_INVALID_HANDLE ); /* not the right type */
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return NULL;
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}
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return grab_object( obj );
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}
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/* get/set the handle reserved flags */
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/* return the new flags (or -1 on error) */
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static int set_handle_info( struct process *process, int handle, int mask, int flags )
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{
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struct handle_entry *entry;
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if (!(entry = get_handle( process, handle ))) return -1;
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mask = (mask << RESERVED_SHIFT) & RESERVED_ALL;
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flags = (flags << RESERVED_SHIFT) & mask;
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entry->access = (entry->access & ~mask) | flags;
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return (entry->access & RESERVED_ALL) >> RESERVED_SHIFT;
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}
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/* duplicate a handle */
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int duplicate_handle( struct process *src, int src_handle, struct process *dst,
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unsigned int access, int inherit, int options )
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{
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int res;
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struct object *obj = get_handle_obj( src, src_handle, 0, NULL );
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if (!obj) return -1;
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if (options & DUP_HANDLE_SAME_ACCESS)
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{
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struct handle_entry *entry = get_handle( src, src_handle );
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if (entry)
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access = entry->access;
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else /* pseudo-handle, give it full access */
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{
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access = STANDARD_RIGHTS_ALL | SPECIFIC_RIGHTS_ALL;
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clear_error();
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}
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}
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access &= ~RESERVED_ALL;
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if (options & DUP_HANDLE_MAKE_GLOBAL)
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res = alloc_global_handle( obj, access );
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else
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res = alloc_handle( dst, obj, access, inherit );
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release_object( obj );
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return res;
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}
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/* open a new handle to an existing object */
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int open_object( const char *name, size_t len, const struct object_ops *ops,
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unsigned int access, int inherit )
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{
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struct object *obj = find_object( name, len );
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if (!obj)
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{
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set_error( ERROR_FILE_NOT_FOUND );
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return -1;
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}
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if (ops && obj->ops != ops)
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{
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release_object( obj );
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set_error( ERROR_INVALID_HANDLE ); /* FIXME: not the right type */
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return -1;
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}
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return alloc_handle( current->process, obj, access, inherit );
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}
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/* close a handle */
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DECL_HANDLER(close_handle)
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{
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close_handle( current->process, req->handle );
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}
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/* get information about a handle */
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DECL_HANDLER(get_handle_info)
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{
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struct get_handle_info_reply *reply = push_reply_data( current, sizeof(*reply) );
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reply->flags = set_handle_info( current->process, req->handle, 0, 0 );
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}
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/* set a handle information */
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DECL_HANDLER(set_handle_info)
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{
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set_handle_info( current->process, req->handle, req->mask, req->flags );
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}
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/* duplicate a handle */
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DECL_HANDLER(dup_handle)
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{
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struct dup_handle_reply reply = { -1 };
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struct process *src, *dst;
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if ((src = get_process_from_handle( req->src_process, PROCESS_DUP_HANDLE )))
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{
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if (req->options & DUP_HANDLE_MAKE_GLOBAL)
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{
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reply.handle = duplicate_handle( src, req->src_handle, NULL,
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req->access, req->inherit, req->options );
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}
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else if ((dst = get_process_from_handle( req->dst_process, PROCESS_DUP_HANDLE )))
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{
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reply.handle = duplicate_handle( src, req->src_handle, dst,
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req->access, req->inherit, req->options );
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release_object( dst );
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}
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/* close the handle no matter what happened */
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if (req->options & DUP_HANDLE_CLOSE_SOURCE)
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close_handle( src, req->src_handle );
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release_object( src );
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}
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add_reply_data( current, &reply, sizeof(reply) );
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}
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