text: /*
   * Server-side file mapping management
   *
   * Copyright (C) 1999 Alexandre Julliard
   *
   * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
   */
  
  #include "config.h"
  #include "wine/port.h"
  
  #include <assert.h>
  #include <stdarg.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <sys/stat.h>
  #ifdef HAVE_SYS_MMAN_H
  # include <sys/mman.h>
  #endif
  #include <unistd.h>
  
  #include "ntstatus.h"
  #define WIN32_NO_STATUS
  #include "windef.h"
  #include "winternl.h"
  
  #include "file.h"
  #include "handle.h"
  #include "thread.h"
  #include "process.h"
  #include "request.h"
  #include "security.h"
  
  /* list of memory ranges, used to store committed info */
  struct ranges
  {
      unsigned int count;
      unsigned int max;
      struct range
      {
          file_pos_t  start;
          file_pos_t  end;
      } ranges[1];
  };
  
  struct mapping
  {
      struct object   obj;             /* object header */
      mem_size_t      size;            /* mapping size */
      unsigned int    flags;           /* SEC_* flags */
      struct fd      *fd;              /* fd for mapped file */
      enum cpu_type   cpu;             /* client CPU (for PE image mapping) */
      pe_image_info_t image;           /* image info (for PE image mapping) */
      struct ranges  *committed;       /* list of committed ranges in this mapping */
      struct file    *shared_file;     /* temp file for shared PE mapping */
      struct list     shared_entry;    /* entry in global shared PE mappings list */
  };
  
  static void mapping_dump( struct object *obj, int verbose );
  static struct object_type *mapping_get_type( struct object *obj );
  static struct fd *mapping_get_fd( struct object *obj );
  static unsigned int mapping_map_access( struct object *obj, unsigned int access );
  static void mapping_destroy( struct object *obj );
  static enum server_fd_type mapping_get_fd_type( struct fd *fd );
  
  static const struct object_ops mapping_ops =
  {
      sizeof(struct mapping),      /* size */
      mapping_dump,                /* dump */
      mapping_get_type,            /* get_type */
      no_add_queue,                /* add_queue */
      NULL,                        /* remove_queue */
      NULL,                        /* signaled */
      NULL,                        /* satisfied */
      no_signal,                   /* signal */
      mapping_get_fd,              /* get_fd */
      mapping_map_access,          /* map_access */
      default_get_sd,              /* get_sd */
      default_set_sd,              /* set_sd */
      no_lookup_name,              /* lookup_name */
      directory_link_name,         /* link_name */
      default_unlink_name,         /* unlink_name */
      no_open_file,                /* open_file */
      fd_close_handle,             /* close_handle */
      mapping_destroy              /* destroy */
  };
  
  static const struct fd_ops mapping_fd_ops =
  {
      default_fd_get_poll_events,   /* get_poll_events */
      default_poll_event,           /* poll_event */
      mapping_get_fd_type,          /* get_fd_type */
      no_fd_read,                   /* read */
      no_fd_write,                  /* write */
      no_fd_flush,                  /* flush */
      no_fd_ioctl,                  /* ioctl */
      no_fd_queue_async,            /* queue_async */
      default_fd_reselect_async     /* reselect_async */
  };
  
  static struct list shared_list = LIST_INIT(shared_list);
  
  static size_t page_mask;
  
  #define ROUND_SIZE(size)  (((size) + page_mask) & ~page_mask)
  
  
  /* extend a file beyond the current end of file */
  static int grow_file( int unix_fd, file_pos_t new_size )
  {
      static const char zero;
      off_t size = new_size;
  
      if (sizeof(new_size) > sizeof(size) && size != new_size)
      {
          set_error( STATUS_INVALID_PARAMETER );
          return 0;
      }
      /* extend the file one byte beyond the requested size and then truncate it */
      /* this should work around ftruncate implementations that can't extend files */
      if (pwrite( unix_fd, &zero, 1, size ) != -1)
      {
          ftruncate( unix_fd, size );
          return 1;
      }
      file_set_error();
      return 0;
  }
  
  /* check if the current directory allows exec mappings */
  static int check_current_dir_for_exec(void)
  {
      int fd;
      char tmpfn[] = "anonmap.XXXXXX";
      void *ret = MAP_FAILED;
  
      fd = mkstemps( tmpfn, 0 );
      if (fd == -1) return 0;
      if (grow_file( fd, 1 ))
      {
          ret = mmap( NULL, get_page_size(), PROT_READ | PROT_EXEC, MAP_PRIVATE, fd, 0 );
          if (ret != MAP_FAILED) munmap( ret, get_page_size() );
      }
      close( fd );
      unlink( tmpfn );
      return (ret != MAP_FAILED);
  }
  
  /* create a temp file for anonymous mappings */
  static int create_temp_file( file_pos_t size )
  {
      static int temp_dir_fd = -1;
      char tmpfn[] = "anonmap.XXXXXX";
      int fd;
  
      if (temp_dir_fd == -1)
      {
          temp_dir_fd = server_dir_fd;
          if (!check_current_dir_for_exec())
          {
              /* the server dir is noexec, try the config dir instead */
              fchdir( config_dir_fd );
              if (check_current_dir_for_exec())
                  temp_dir_fd = config_dir_fd;
              else  /* neither works, fall back to server dir */
                  fchdir( server_dir_fd );
          }
      }
      else if (temp_dir_fd != server_dir_fd) fchdir( temp_dir_fd );
  
      fd = mkstemps( tmpfn, 0 );
      if (fd != -1)
      {
          if (!grow_file( fd, size ))
          {
              close( fd );
              fd = -1;
          }
          unlink( tmpfn );
      }
      else file_set_error();
  
      if (temp_dir_fd != server_dir_fd) fchdir( server_dir_fd );
      return fd;
  }
  
  /* find the shared PE mapping for a given mapping */
  static struct file *get_shared_file( struct mapping *mapping )
  {
      struct mapping *ptr;
  
      LIST_FOR_EACH_ENTRY( ptr, &shared_list, struct mapping, shared_entry )
          if (is_same_file_fd( ptr->fd, mapping->fd ))
              return (struct file *)grab_object( ptr->shared_file );
      return NULL;
  }
  
  /* return the size of the memory mapping and file range of a given section */
  static inline void get_section_sizes( const IMAGE_SECTION_HEADER *sec, size_t *map_size,
                                        off_t *file_start, size_t *file_size )
  {
      static const unsigned int sector_align = 0x1ff;
  
      if (!sec->Misc.VirtualSize) *map_size = ROUND_SIZE( sec->SizeOfRawData );
      else *map_size = ROUND_SIZE( sec->Misc.VirtualSize );
  
      *file_start = sec->PointerToRawData & ~sector_align;
      *file_size = (sec->SizeOfRawData + (sec->PointerToRawData & sector_align) + sector_align) & ~sector_align;
      if (*file_size > *map_size) *file_size = *map_size;
  }
  
  /* add a range to the committed list */
  static void add_committed_range( struct mapping *mapping, file_pos_t start, file_pos_t end )
  {
      unsigned int i, j;
      struct range *ranges;
  
      if (!mapping->committed) return;  /* everything committed already */
  
      for (i = 0, ranges = mapping->committed->ranges; i < mapping->committed->count; i++)
      {
          if (ranges[i].start > end) break;
          if (ranges[i].end < start) continue;
          if (ranges[i].start > start) ranges[i].start = start;   /* extend downwards */
          if (ranges[i].end < end)  /* extend upwards and maybe merge with next */
          {
              for (j = i + 1; j < mapping->committed->count; j++)
              {
                  if (ranges[j].start > end) break;
                  if (ranges[j].end > end) end = ranges[j].end;
              }
              if (j > i + 1)
              {
                  memmove( &ranges[i + 1], &ranges[j], (mapping->committed->count - j) * sizeof(*ranges) );
                  mapping->committed->count -= j - (i + 1);
              }
              ranges[i].end = end;
          }
          return;
      }
  
      /* now add a new range */
  
      if (mapping->committed->count == mapping->committed->max)
      {
          unsigned int new_size = mapping->committed->max * 2;
          struct ranges *new_ptr = realloc( mapping->committed, offsetof( struct ranges, ranges[new_size] ));
          if (!new_ptr) return;
          new_ptr->max = new_size;
          ranges = new_ptr->ranges;
          mapping->committed = new_ptr;
      }
      memmove( &ranges[i + 1], &ranges[i], (mapping->committed->count - i) * sizeof(*ranges) );
      ranges[i].start = start;
      ranges[i].end = end;
      mapping->committed->count++;
  }
  
  /* find the range containing start and return whether it's committed */
  static int find_committed_range( struct mapping *mapping, file_pos_t start, mem_size_t *size )
  {
      unsigned int i;
      struct range *ranges;
  
      if (!mapping->committed)  /* everything is committed */
      {
          *size = mapping->size - start;
          return 1;
      }
      for (i = 0, ranges = mapping->committed->ranges; i < mapping->committed->count; i++)
      {
          if (ranges[i].start > start)
          {
              *size = ranges[i].start - start;
              return 0;
          }
          if (ranges[i].end > start)
          {
              *size = ranges[i].end - start;
              return 1;
          }
      }
      *size = mapping->size - start;
      return 0;
  }
  
  /* allocate and fill the temp file for a shared PE image mapping */
  static int build_shared_mapping( struct mapping *mapping, int fd,
                                   IMAGE_SECTION_HEADER *sec, unsigned int nb_sec )
  {
      unsigned int i;
      mem_size_t total_size;
      size_t file_size, map_size, max_size;
      off_t shared_pos, read_pos, write_pos;
      char *buffer = NULL;
      int shared_fd;
      long toread;
  
      /* compute the total size of the shared mapping */
  
      total_size = max_size = 0;
      for (i = 0; i < nb_sec; i++)
      {
          if ((sec[i].Characteristics & IMAGE_SCN_MEM_SHARED) &&
              (sec[i].Characteristics & IMAGE_SCN_MEM_WRITE))
          {
              get_section_sizes( &sec[i], &map_size, &read_pos, &file_size );
              if (file_size > max_size) max_size = file_size;
              total_size += map_size;
          }
      }
      if (!total_size) return 1;  /* nothing to do */
  
      if ((mapping->shared_file = get_shared_file( mapping ))) return 1;
  
      /* create a temp file for the mapping */
  
      if ((shared_fd = create_temp_file( total_size )) == -1) return 0;
      if (!(mapping->shared_file = create_file_for_fd( shared_fd, FILE_GENERIC_READ|FILE_GENERIC_WRITE, 0 )))
          return 0;
  
      if (!(buffer = malloc( max_size ))) goto error;
  
      /* copy the shared sections data into the temp file */
  
      shared_pos = 0;
      for (i = 0; i < nb_sec; i++)
      {
          if (!(sec[i].Characteristics & IMAGE_SCN_MEM_SHARED)) continue;
          if (!(sec[i].Characteristics & IMAGE_SCN_MEM_WRITE)) continue;
          get_section_sizes( &sec[i], &map_size, &read_pos, &file_size );
          write_pos = shared_pos;
          shared_pos += map_size;
          if (!sec[i].PointerToRawData || !file_size) continue;
          toread = file_size;
          while (toread)
          {
              long res = pread( fd, buffer + file_size - toread, toread, read_pos );
              if (!res && toread < 0x200)  /* partial sector at EOF is not an error */
              {
                  file_size -= toread;
                  break;
              }
              if (res <= 0) goto error;
              toread -= res;
              read_pos += res;
          }
          if (pwrite( shared_fd, buffer, file_size, write_pos ) != file_size) goto error;
      }
      free( buffer );
      return 1;
  
   error:
      release_object( mapping->shared_file );
      mapping->shared_file = NULL;
      free( buffer );
      return 0;
  }
  
  /* retrieve the mapping parameters for an executable (PE) image */
  static unsigned int get_image_params( struct mapping *mapping, file_pos_t file_size, int unix_fd )
  {
      IMAGE_DOS_HEADER dos;
      IMAGE_SECTION_HEADER *sec = NULL;
      struct
      {
          DWORD Signature;
          IMAGE_FILE_HEADER FileHeader;
          union
          {
              IMAGE_OPTIONAL_HEADER32 hdr32;
              IMAGE_OPTIONAL_HEADER64 hdr64;
          } opt;
      } nt;
      off_t pos;
      int size;
  
      /* load the headers */
  
      if (!file_size) return STATUS_INVALID_FILE_FOR_SECTION;
      if (pread( unix_fd, &dos, sizeof(dos), 0 ) != sizeof(dos)) return STATUS_INVALID_IMAGE_NOT_MZ;
      if (dos.e_magic != IMAGE_DOS_SIGNATURE) return STATUS_INVALID_IMAGE_NOT_MZ;
      pos = dos.e_lfanew;
  
      size = pread( unix_fd, &nt, sizeof(nt), pos );
      if (size < sizeof(nt.Signature) + sizeof(nt.FileHeader)) return STATUS_INVALID_IMAGE_FORMAT;
      /* zero out Optional header in the case it's not present or partial */
      size = min( size, sizeof(nt.Signature) + sizeof(nt.FileHeader) + nt.FileHeader.SizeOfOptionalHeader );
      if (size < sizeof(nt)) memset( (char *)&nt + size, 0, sizeof(nt) - size );
      if (nt.Signature != IMAGE_NT_SIGNATURE)
      {
          if (*(WORD *)&nt.Signature == IMAGE_OS2_SIGNATURE) return STATUS_INVALID_IMAGE_NE_FORMAT;
          return STATUS_INVALID_IMAGE_PROTECT;
      }
  
      mapping->cpu = current->process->cpu;
      switch (mapping->cpu)
      {
      case CPU_x86:
          if (nt.FileHeader.Machine != IMAGE_FILE_MACHINE_I386) return STATUS_INVALID_IMAGE_FORMAT;
          if (nt.opt.hdr32.Magic != IMAGE_NT_OPTIONAL_HDR32_MAGIC) return STATUS_INVALID_IMAGE_FORMAT;
          break;
      case CPU_x86_64:
          if (nt.FileHeader.Machine != IMAGE_FILE_MACHINE_AMD64) return STATUS_INVALID_IMAGE_FORMAT;
          if (nt.opt.hdr64.Magic != IMAGE_NT_OPTIONAL_HDR64_MAGIC) return STATUS_INVALID_IMAGE_FORMAT;
          break;
      case CPU_POWERPC:
          if (nt.FileHeader.Machine != IMAGE_FILE_MACHINE_POWERPC) return STATUS_INVALID_IMAGE_FORMAT;
          if (nt.opt.hdr32.Magic != IMAGE_NT_OPTIONAL_HDR32_MAGIC) return STATUS_INVALID_IMAGE_FORMAT;
          break;
      case CPU_ARM:
          if (nt.FileHeader.Machine != IMAGE_FILE_MACHINE_ARM &&
              nt.FileHeader.Machine != IMAGE_FILE_MACHINE_THUMB &&
              nt.FileHeader.Machine != IMAGE_FILE_MACHINE_ARMNT) return STATUS_INVALID_IMAGE_FORMAT;
          if (nt.opt.hdr32.Magic != IMAGE_NT_OPTIONAL_HDR32_MAGIC) return STATUS_INVALID_IMAGE_FORMAT;
          break;
      case CPU_ARM64:
          if (nt.FileHeader.Machine != IMAGE_FILE_MACHINE_ARM64) return STATUS_INVALID_IMAGE_FORMAT;
          if (nt.opt.hdr64.Magic != IMAGE_NT_OPTIONAL_HDR64_MAGIC) return STATUS_INVALID_IMAGE_FORMAT;
          break;
      default:
          return STATUS_INVALID_IMAGE_FORMAT;
      }
  
      switch (nt.opt.hdr32.Magic)
      {
      case IMAGE_NT_OPTIONAL_HDR32_MAGIC:
          mapping->image.base           = nt.opt.hdr32.ImageBase;
          mapping->image.entry_point    = nt.opt.hdr32.ImageBase + nt.opt.hdr32.AddressOfEntryPoint;
          mapping->image.map_size       = ROUND_SIZE( nt.opt.hdr32.SizeOfImage );
          mapping->image.stack_size     = nt.opt.hdr32.SizeOfStackReserve;
          mapping->image.stack_commit   = nt.opt.hdr32.SizeOfStackCommit;
          mapping->image.subsystem      = nt.opt.hdr32.Subsystem;
          mapping->image.subsystem_low  = nt.opt.hdr32.MinorSubsystemVersion;
          mapping->image.subsystem_high = nt.opt.hdr32.MajorSubsystemVersion;
          mapping->image.dll_charact    = nt.opt.hdr32.DllCharacteristics;
          mapping->image.loader_flags   = nt.opt.hdr32.LoaderFlags;
          mapping->image.header_size    = nt.opt.hdr32.SizeOfHeaders;
          mapping->image.checksum       = nt.opt.hdr32.CheckSum;
          break;
      case IMAGE_NT_OPTIONAL_HDR64_MAGIC:
          mapping->image.base           = nt.opt.hdr64.ImageBase;
          mapping->image.entry_point    = nt.opt.hdr64.ImageBase + nt.opt.hdr64.AddressOfEntryPoint;
          mapping->image.map_size       = ROUND_SIZE( nt.opt.hdr64.SizeOfImage );
          mapping->image.stack_size     = nt.opt.hdr64.SizeOfStackReserve;
          mapping->image.stack_commit   = nt.opt.hdr64.SizeOfStackCommit;
          mapping->image.subsystem      = nt.opt.hdr64.Subsystem;
          mapping->image.subsystem_low  = nt.opt.hdr64.MinorSubsystemVersion;
          mapping->image.subsystem_high = nt.opt.hdr64.MajorSubsystemVersion;
          mapping->image.dll_charact    = nt.opt.hdr64.DllCharacteristics;
          mapping->image.loader_flags   = nt.opt.hdr64.LoaderFlags;
          mapping->image.header_size    = nt.opt.hdr64.SizeOfHeaders;
          mapping->image.checksum       = nt.opt.hdr64.CheckSum;
          break;
      }
      mapping->image.image_charact = nt.FileHeader.Characteristics;
      mapping->image.machine       = nt.FileHeader.Machine;
      mapping->image.zerobits      = 0; /* FIXME */
      mapping->image.gp            = 0; /* FIXME */
      mapping->image.contains_code = 0; /* FIXME */
      mapping->image.image_flags   = 0; /* FIXME */
      mapping->image.file_size     = file_size;
  
      /* load the section headers */
  
      pos += sizeof(nt.Signature) + sizeof(nt.FileHeader) + nt.FileHeader.SizeOfOptionalHeader;
      size = sizeof(*sec) * nt.FileHeader.NumberOfSections;
      if (!mapping->size) mapping->size = mapping->image.map_size;
      else if (mapping->size > mapping->image.map_size) return STATUS_SECTION_TOO_BIG;
      if (pos + size > mapping->image.map_size) return STATUS_INVALID_FILE_FOR_SECTION;
      if (pos + size > mapping->image.header_size) mapping->image.header_size = pos + size;
      if (!(sec = malloc( size ))) goto error;
      if (pread( unix_fd, sec, size, pos ) != size) goto error;
  
      if (!build_shared_mapping( mapping, unix_fd, sec, nt.FileHeader.NumberOfSections )) goto error;
  
      if (mapping->shared_file) list_add_head( &shared_list, &mapping->shared_entry );
  
      free( sec );
      return 0;
  
   error:
      free( sec );
      return STATUS_INVALID_FILE_FOR_SECTION;
  }
  
  static unsigned int get_mapping_flags( obj_handle_t handle, unsigned int flags )
  {
      switch (flags & (SEC_IMAGE | SEC_RESERVE | SEC_COMMIT | SEC_FILE))
      {
      case SEC_IMAGE:
          if (flags & (SEC_WRITECOMBINE | SEC_LARGE_PAGES)) break;
          if (handle) return SEC_FILE | SEC_IMAGE;
          set_error( STATUS_INVALID_FILE_FOR_SECTION );
          return 0;
      case SEC_COMMIT:
          if (!handle) return flags;
          /* fall through */
      case SEC_RESERVE:
          if (flags & SEC_LARGE_PAGES) break;
          if (handle) return SEC_FILE | (flags & (SEC_NOCACHE | SEC_WRITECOMBINE));
          return flags;
      }
      set_error( STATUS_INVALID_PARAMETER );
      return 0;
  }
  
  
  static struct object *create_mapping( struct object *root, const struct unicode_str *name,
                                        unsigned int attr, mem_size_t size, unsigned int flags,
                                        obj_handle_t handle, unsigned int file_access,
                                        const struct security_descriptor *sd )
  {
      struct mapping *mapping;
      struct file *file;
      struct fd *fd;
      int unix_fd;
      struct stat st;
  
      if (!page_mask) page_mask = sysconf( _SC_PAGESIZE ) - 1;
  
      if (!(mapping = create_named_object( root, &mapping_ops, name, attr, sd )))
          return NULL;
      if (get_error() == STATUS_OBJECT_NAME_EXISTS)
          return &mapping->obj;  /* Nothing else to do */
  
      mapping->size        = size;
      mapping->fd          = NULL;
      mapping->shared_file = NULL;
      mapping->committed   = NULL;
  
      if (!(mapping->flags = get_mapping_flags( handle, flags ))) goto error;
  
      if (handle)
      {
          const unsigned int sharing = FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE;
          unsigned int mapping_access = FILE_MAPPING_ACCESS;
  
          if (!(file = get_file_obj( current->process, handle, file_access ))) goto error;
          fd = get_obj_fd( (struct object *)file );
  
          /* file sharing rules for mappings are different so we use magic the access rights */
          if (flags & SEC_IMAGE) mapping_access |= FILE_MAPPING_IMAGE;
          else if (file_access & FILE_WRITE_DATA) mapping_access |= FILE_MAPPING_WRITE;
  
          if (!(mapping->fd = get_fd_object_for_mapping( fd, mapping_access, sharing )))
          {
              mapping->fd = dup_fd_object( fd, mapping_access, sharing, FILE_SYNCHRONOUS_IO_NONALERT );
              if (mapping->fd) set_fd_user( mapping->fd, &mapping_fd_ops, NULL );
          }
          release_object( file );
          release_object( fd );
          if (!mapping->fd) goto error;
  
          if ((unix_fd = get_unix_fd( mapping->fd )) == -1) goto error;
          if (fstat( unix_fd, &st ) == -1)
          {
              file_set_error();
              goto error;
          }
          if (flags & SEC_IMAGE)
          {
              unsigned int err = get_image_params( mapping, st.st_size, unix_fd );
              if (!err) return &mapping->obj;
              set_error( err );
              goto error;
          }
          if (!mapping->size)
          {
              if (!(mapping->size = st.st_size))
              {
                  set_error( STATUS_MAPPED_FILE_SIZE_ZERO );
                  goto error;
              }
          }
          else if (st.st_size < mapping->size)
          {
              if (!(file_access & FILE_WRITE_DATA))
              {
                  set_error( STATUS_SECTION_TOO_BIG );
                  goto error;
              }
              if (!grow_file( unix_fd, mapping->size )) goto error;
          }
      }
      else  /* Anonymous mapping (no associated file) */
      {
          if (!mapping->size)
          {
              set_error( STATUS_INVALID_PARAMETER );
              goto error;
          }
          if (flags & SEC_RESERVE)
          {
              if (!(mapping->committed = mem_alloc( offsetof(struct ranges, ranges[8]) ))) goto error;
              mapping->committed->count = 0;
              mapping->committed->max   = 8;
          }
          mapping->size = (mapping->size + page_mask) & ~((mem_size_t)page_mask);
          if ((unix_fd = create_temp_file( mapping->size )) == -1) goto error;
          if (!(mapping->fd = create_anonymous_fd( &mapping_fd_ops, unix_fd, &mapping->obj,
                                                   FILE_SYNCHRONOUS_IO_NONALERT ))) goto error;
          allow_fd_caching( mapping->fd );
      }
      return &mapping->obj;
  
   error:
      release_object( mapping );
      return NULL;
  }
  
  struct mapping *get_mapping_obj( struct process *process, obj_handle_t handle, unsigned int access )
  {
      return (struct mapping *)get_handle_obj( process, handle, access, &mapping_ops );
  }
  
  /* open a new file handle to the file backing the mapping */
  obj_handle_t open_mapping_file( struct process *process, struct mapping *mapping,
                                  unsigned int access, unsigned int sharing )
  {
      obj_handle_t handle;
      struct file *file = create_file_for_fd_obj( mapping->fd, access, sharing );
  
      if (!file) return 0;
      handle = alloc_handle( process, file, access, 0 );
      release_object( file );
      return handle;
  }
  
  struct mapping *grab_mapping_unless_removable( struct mapping *mapping )
  {
      if (is_fd_removable( mapping->fd )) return NULL;
      return (struct mapping *)grab_object( mapping );
  }
  
  static void mapping_dump( struct object *obj, int verbose )
  {
      struct mapping *mapping = (struct mapping *)obj;
      assert( obj->ops == &mapping_ops );
      fprintf( stderr, "Mapping size=%08x%08x flags=%08x fd=%p shared_file=%p\n",
               (unsigned int)(mapping->size >> 32), (unsigned int)mapping->size,
               mapping->flags, mapping->fd, mapping->shared_file );
  }
  
  static struct object_type *mapping_get_type( struct object *obj )
  {
      static const WCHAR name[] = {'S','e','c','t','i','o','n'};
      static const struct unicode_str str = { name, sizeof(name) };
      return get_object_type( &str );
  }
  
  static struct fd *mapping_get_fd( struct object *obj )
  {
      struct mapping *mapping = (struct mapping *)obj;
      return (struct fd *)grab_object( mapping->fd );
  }
  
  static unsigned int mapping_map_access( struct object *obj, unsigned int access )
  {
      if (access & GENERIC_READ)    access |= STANDARD_RIGHTS_READ | SECTION_QUERY | SECTION_MAP_READ;
      if (access & GENERIC_WRITE)   access |= STANDARD_RIGHTS_WRITE | SECTION_MAP_WRITE;
      if (access & GENERIC_EXECUTE) access |= STANDARD_RIGHTS_EXECUTE | SECTION_MAP_EXECUTE;
      if (access & GENERIC_ALL)     access |= SECTION_ALL_ACCESS;
      return access & ~(GENERIC_READ | GENERIC_WRITE | GENERIC_EXECUTE | GENERIC_ALL);
  }
  
  static void mapping_destroy( struct object *obj )
  {
      struct mapping *mapping = (struct mapping *)obj;
      assert( obj->ops == &mapping_ops );
      if (mapping->fd) release_object( mapping->fd );
      if (mapping->shared_file)
      {
          release_object( mapping->shared_file );
          list_remove( &mapping->shared_entry );
      }
      free( mapping->committed );
  }
  
  static enum server_fd_type mapping_get_fd_type( struct fd *fd )
  {
      return FD_TYPE_FILE;
  }
  
  int get_page_size(void)
  {
      if (!page_mask) page_mask = sysconf( _SC_PAGESIZE ) - 1;
      return page_mask + 1;
  }
  
  /* create a file mapping */
  DECL_HANDLER(create_mapping)
  {
      struct object *root, *obj;
      struct unicode_str name;
      const struct security_descriptor *sd;
      const struct object_attributes *objattr = get_req_object_attributes( &sd, &name, &root );
  
      if (!objattr) return;
  
      if ((obj = create_mapping( root, &name, objattr->attributes, req->size, req->flags,
                                 req->file_handle, req->file_access, sd )))
      {
          if (get_error() == STATUS_OBJECT_NAME_EXISTS)
              reply->handle = alloc_handle( current->process, obj, req->access, objattr->attributes );
          else
              reply->handle = alloc_handle_no_access_check( current->process, obj,
                                                            req->access, objattr->attributes );
          release_object( obj );
      }
  
      if (root) release_object( root );
  }
  
  /* open a handle to a mapping */
  DECL_HANDLER(open_mapping)
  {
      struct unicode_str name = get_req_unicode_str();
  
      reply->handle = open_object( current->process, req->rootdir, req->access,
                                   &mapping_ops, &name, req->attributes );
  }
  
  /* get a mapping information */
  DECL_HANDLER(get_mapping_info)
  {
      struct mapping *mapping;
      struct fd *fd;
  
      if (!(mapping = get_mapping_obj( current->process, req->handle, req->access ))) return;
  
      reply->size    = mapping->size;
      reply->flags   = mapping->flags;
  
      if (mapping->flags & SEC_IMAGE)
          set_reply_data( &mapping->image, min( sizeof(mapping->image), get_reply_max_size() ));
  
      if (!(req->access & (SECTION_MAP_READ | SECTION_MAP_WRITE)))  /* query only */
      {
          release_object( mapping );
          return;
      }
  
      if ((mapping->flags & SEC_IMAGE) && mapping->cpu != current->process->cpu)
      {
          set_error( STATUS_INVALID_IMAGE_FORMAT );
          release_object( mapping );
          return;
      }
  
      if ((fd = get_obj_fd( &mapping->obj )))
      {
          if (!is_fd_removable(fd)) reply->mapping = alloc_handle( current->process, mapping, 0, 0 );
          release_object( fd );
      }
      if (mapping->shared_file)
      {
          if (!(reply->shared_file = alloc_handle( current->process, mapping->shared_file,
                                                   GENERIC_READ|GENERIC_WRITE, 0 )))
          {
              if (reply->mapping) close_handle( current->process, reply->mapping );
          }
      }
      release_object( mapping );
  }
  
  /* get a range of committed pages in a file mapping */
  DECL_HANDLER(get_mapping_committed_range)
  {
      struct mapping *mapping;
  
      if ((mapping = get_mapping_obj( current->process, req->handle, 0 )))
      {
          if (!(req->offset & page_mask) && req->offset < mapping->size)
              reply->committed = find_committed_range( mapping, req->offset, &reply->size );
          else
              set_error( STATUS_INVALID_PARAMETER );
  
          release_object( mapping );
      }
  }
  
  /* add a range to the committed pages in a file mapping */
  DECL_HANDLER(add_mapping_committed_range)
  {
      struct mapping *mapping;
  
      if ((mapping = get_mapping_obj( current->process, req->handle, 0 )))
      {
          if (!(req->size & page_mask) &&
              !(req->offset & page_mask) &&
              req->offset < mapping->size &&
              req->size > 0 &&
              req->size <= mapping->size - req->offset)
              add_committed_range( mapping, req->offset, req->offset + req->size );
          else
              set_error( STATUS_INVALID_PARAMETER );
  
          release_object( mapping );
      }
  }
  