server/mapping.c

   1 /*
   2  * Server-side file mapping management
   3  *
   4  * Copyright (C) 1999 Alexandre Julliard
   5  */
   6
   7 #include <assert.h>
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10 #include <unistd.h>
  11
  12 #include "config.h"
  13 #include "winerror.h"
  14 #include "winnt.h"
  15 #include "winbase.h"
  16
  17 #include "handle.h"
  18 #include "thread.h"
  19 #include "request.h"
  20
  21 struct mapping
  22 {
  23     struct object  obj;             /* object header */
  24     int            size_high;       /* mapping size */
  25     int            size_low;        /* mapping size */
  26     int            protect;         /* protection flags */
  27     struct file   *file;            /* file mapped */
  28 };
  29
  30 static void mapping_dump( struct object *obj, int verbose );
  31 static void mapping_destroy( struct object *obj );
  32
  33 static const struct object_ops mapping_ops =
  34 {
  35     sizeof(struct mapping),
  36     mapping_dump,
  37     no_add_queue,
  38     NULL,  /* should never get called */
  39     NULL,  /* should never get called */
  40     NULL,  /* should never get called */
  41     no_read_fd,
  42     no_write_fd,
  43     no_flush,
  44     no_get_file_info,
  45     mapping_destroy
  46 };
  47
  48 #ifdef __i386__
  49
  50 /* These are always the same on an i386, and it will be faster this way */
  51 # define page_mask  0xfff
  52 # define page_shift 12
  53 # define init_page_size() /* nothing */
  54
  55 #else  /* __i386__ */
  56
  57 static int page_shift, page_mask;
  58
  59 static void init_page_size(void)
  60 {
  61     int page_size;
  62 # ifdef HAVE_GETPAGESIZE
  63     page_size = getpagesize();
  64 # else
  65 #  ifdef __svr4__
  66     page_size = sysconf(_SC_PAGESIZE);
  67 #  else
  68 #   error Cannot get the page size on this platform
  69 #  endif
  70 # endif
  71     page_mask = page_size - 1;
  72     /* Make sure we have a power of 2 */
  73     assert( !(page_size & page_mask) );
  74     page_shift = 0;
  75     while ((1 << page_shift) != page_size) page_shift++;
  76 }
  77 #endif  /* __i386__ */
  78
  79 #define ROUND_ADDR(addr) \
  80    ((int)(addr) & ~page_mask)
  81
  82 #define ROUND_SIZE(addr,size) \
  83    (((int)(size) + ((int)(addr) & page_mask) + page_mask) & ~page_mask)
  84
  85
  86 static struct object *create_mapping( int size_high, int size_low, int protect,
  87                                       int handle, const char *name, size_t len )
  88 {
  89     struct mapping *mapping;
  90     int access = 0;
  91
  92     if (!page_mask) init_page_size();
  93
  94     if (!(mapping = create_named_object( &mapping_ops, name, len )))
  95         return NULL;
  96     if (get_error() == ERROR_ALREADY_EXISTS)
  97         return &mapping->obj;  /* Nothing else to do */
  98
  99     if (protect & VPROT_READ) access |= GENERIC_READ;
 100     if (protect & VPROT_WRITE) access |= GENERIC_WRITE;
 101
 102     if (handle != -1)
 103     {
 104         if (!(mapping->file = get_file_obj( current->process, handle, access ))) goto error;
 105         if (!size_high && !size_low)
 106         {
 107             struct get_file_info_request req;
 108             struct object *obj = (struct object *)mapping->file;
 109             obj->ops->get_file_info( obj, &req );
 110             size_high = req.size_high;
 111             size_low  = ROUND_SIZE( 0, req.size_low );
 112         }
 113         else if (!grow_file( mapping->file, size_high, size_low )) goto error;
 114     }
 115     else  /* Anonymous mapping (no associated file) */
 116     {
 117         if (!size_high && !size_low)
 118         {
 119             set_error( ERROR_INVALID_PARAMETER );
 120             mapping->file = NULL;
 121             goto error;
 122         }
 123         if (!(mapping->file = create_temp_file( access ))) goto error;
 124         if (!grow_file( mapping->file, size_high, size_low )) goto error;
 125     }
 126     mapping->size_high = size_high;
 127     mapping->size_low  = ROUND_SIZE( 0, size_low );
 128     mapping->protect   = protect;
 129     return &mapping->obj;
 130
 131  error:
 132     release_object( mapping );
 133     return NULL;
 134 }
 135
 136 static void mapping_dump( struct object *obj, int verbose )
 137 {
 138     struct mapping *mapping = (struct mapping *)obj;
 139     assert( obj->ops == &mapping_ops );
 140     fprintf( stderr, "Mapping size=%08x%08x prot=%08x file=%p name='%s'\n",
 141              mapping->size_high, mapping->size_low, mapping->protect,
 142              mapping->file, get_object_name( &mapping->obj ) );
 143 }
 144
 145 static void mapping_destroy( struct object *obj )
 146 {
 147     struct mapping *mapping = (struct mapping *)obj;
 148     assert( obj->ops == &mapping_ops );
 149     if (mapping->file) release_object( mapping->file );
 150 }
 151
 152 /* create a file mapping */
 153 DECL_HANDLER(create_mapping)
 154 {
 155     size_t len = get_req_strlen( req->name );
 156     struct object *obj;
 157
 158     req->handle = -1;
 159     if ((obj = create_mapping( req->size_high, req->size_low,
 160                                req->protect, req->file_handle, req->name, len )))
 161     {
 162         int access = FILE_MAP_ALL_ACCESS;
 163         if (!(req->protect & VPROT_WRITE)) access &= ~FILE_MAP_WRITE;
 164         req->handle = alloc_handle( current->process, obj, access, req->inherit );
 165         release_object( obj );
 166     }
 167 }
 168
 169 /* open a handle to a mapping */
 170 DECL_HANDLER(open_mapping)
 171 {
 172     size_t len = get_req_strlen( req->name );
 173     req->handle = open_object( req->name, len, &mapping_ops, req->access, req->inherit );
 174 }
 175
 176 /* get a mapping information */
 177 DECL_HANDLER(get_mapping_info)
 178 {
 179     struct mapping *mapping;
 180
 181     if ((mapping = (struct mapping *)get_handle_obj( current->process, req->handle,
 182                                                      0, &mapping_ops )))
 183     {
 184         req->size_high = mapping->size_high;
 185         req->size_low  = mapping->size_low;
 186         req->protect   = mapping->protect;
 187         if (mapping->file) set_reply_fd( current, file_get_mmap_fd( mapping->file ) );
 188         release_object( mapping );
 189     }
 190 }
 191