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Sweden-Number/server/handle.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;
};
static struct process *initial_process;
/* 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
/* grow a handle table */
/* return 1 if OK, 0 on error */
static int grow_handle_table( struct process *process )
{
struct handle_entry *new_entries;
int count = process->handle_count;
if (count >= INT_MAX / 2) return 0;
count *= 2;
if (!(new_entries = realloc( process->entries, count * sizeof(struct handle_entry) )))
{
SET_ERROR( ERROR_OUTOFMEMORY );
return 0;
}
process->handle_count = count;
process->entries = new_entries;
return 1;
}
/* 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_entry *entry;
int handle;
assert( !(access & RESERVED_ALL) );
if (inherit) access |= RESERVED_INHERIT;
/* find the first free entry */
if (!(entry = process->entries)) return -1;
for (handle = 0; handle <= process->handle_last; handle++, entry++)
if (!entry->ptr) goto found;
if (handle >= process->handle_count)
{
if (!grow_handle_table( process )) return -1;
entry = process->entries + handle; /* the table may have moved */
}
process->handle_last = handle;
found:
entry->ptr = grab_object( obj );
entry->access = access;
return handle + 1; /* avoid handle 0 */
}
/* return an handle entry, or NULL if the handle is invalid */
static struct handle_entry *get_handle( struct process *process, int handle )
{
struct handle_entry *entry;
if (HANDLE_IS_GLOBAL(handle))
{
handle = HANDLE_GLOBAL_TO_LOCAL(handle);
process = initial_process;
}
handle--; /* handles start at 1 */
if ((handle < 0) || (handle > process->handle_last)) goto error;
entry = process->entries + handle;
if (!entry->ptr) goto error;
return entry;
error:
SET_ERROR( ERROR_INVALID_HANDLE );
return NULL;
}
/* attempt to shrink a table */
/* return 1 if OK, 0 on error */
static int shrink_handle_table( struct process *process )
{
struct handle_entry *new_entries;
struct handle_entry *entry = process->entries + process->handle_last;
int count = process->handle_count;
while (process->handle_last >= 0)
{
if (entry->ptr) break;
process->handle_last--;
entry--;
}
if (process->handle_last >= count / 4) return 1; /* no need to shrink */
if (count < MIN_HANDLE_ENTRIES * 2) return 1; /* too small to shrink */
count /= 2;
if (!(new_entries = realloc( process->entries,
count * sizeof(struct handle_entry) )))
return 0;
process->handle_count = count;
process->entries = new_entries;
return 1;
}
/* copy the handle table of the parent process */
/* return 1 if OK, 0 on error */
int copy_handle_table( struct process *process, struct process *parent )
{
struct handle_entry *ptr;
int i, count, last;
if (!parent) /* first process */
{
if (!initial_process) initial_process = process;
count = MIN_HANDLE_ENTRIES;
last = -1;
}
else
{
assert( parent->entries );
count = parent->handle_count;
last = parent->handle_last;
}
if (!(ptr = mem_alloc( count * sizeof(struct handle_entry)))) return 0;
process->entries = ptr;
process->handle_count = count;
process->handle_last = last;
if (last >= 0)
{
memcpy( ptr, parent->entries, (last + 1) * sizeof(struct handle_entry) );
for (i = 0; i <= 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( process );
return 1;
}
/* 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_entry *entry;
struct object *obj;
if (HANDLE_IS_GLOBAL(handle))
{
handle = HANDLE_GLOBAL_TO_LOCAL(handle);
process = initial_process;
}
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;
if (handle-1 == process->handle_last) shrink_handle_table( process );
release_object( obj );
return 1;
}
/* 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 handle_entry *entry = get_handle( src, src_handle );
if (!entry) return -1;
if (options & DUP_HANDLE_SAME_ACCESS) access = entry->access;
if (options & DUP_HANDLE_MAKE_GLOBAL) dst = initial_process;
access &= ~RESERVED_ALL;
res = alloc_handle( dst, entry->ptr, access, inherit );
if (options & DUP_HANDLE_MAKE_GLOBAL) res = HANDLE_LOCAL_TO_GLOBAL(res);
return res;
}
/* free the process handle entries */
void free_handles( struct process *process )
{
struct handle_entry *entry;
int handle;
if (!(entry = process->entries)) return;
for (handle = 0; handle <= process->handle_last; handle++, entry++)
{
struct object *obj = entry->ptr;
entry->ptr = NULL;
if (obj) release_object( obj );
}
free( process->entries );
process->handle_count = 0;
process->handle_last = -1;
process->entries = NULL;
}
/* 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 );
}
/* dump a handle table on stdout */
void dump_handles( struct process *process )
{
struct handle_entry *entry;
int i;
if (!process->entries) return;
entry = process->entries;
for (i = 0; i <= process->handle_last; i++, entry++)
{
if (!entry->ptr) continue;
printf( "%5d: %p %08x ", i + 1, entry->ptr, entry->access );
entry->ptr->ops->dump( entry->ptr, 0 );
}
}
/* 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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