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Sweden-Number/server/handle.c

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