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