osfmk/man/vm_write.html

   1 <h2>vm_write</h2>
   2 <hr>
   3 <p>
   4 <strong>Function</strong> - Write data to the specified address in the target task's address space.
   5 <h3>SYNOPSIS</h3>
   6 <pre>
   7 <strong>kern_return_t   vm_write</strong>
   8                 <strong>(vm_task_t</strong>                          <var>target_task</var>,
   9                  <strong>vm_address_t</strong>                           <var>address</var>,
  10                  <strong>pointer_t</strong>                                 <var>data</var>,
  11                  <strong>mach_msg_type_number_t</strong>              <var>data_count</var><strong>);</strong>
  12 </pre>
  13 <h3>PARAMETERS</h3>
  14 <dl>
  15 <p>
  16 <dt> <var>target_task</var>
  17 <dd>
  18 [in task send right]
  19 The port for the task whose memory is to be
  20 written.
  21 <p>
  22 <dt> <var>address</var>
  23 <dd>
  24 [in scalar]
  25 The address at which to start the write.
  26 <p>
  27 <dt> <var>data</var>
  28 <dd>
  29 [pointer to page aligned in array of bytes]
  30 An array of data to be
  31 written.
  32 <p>
  33 <dt> <var>data_count</var>
  34 <dd>
  35 [in scalar]
  36 The number of bytes in the array.
  37 </dl>
  38 <h3>DESCRIPTION</h3>
  39 <p>
  40 The <strong>vm_write</strong> function writes an array of data to a
  41 task's virtual memory.  It
  42 allows one task to write to another task's memory.
  43 <p>
  44 The result of <strong>vm_write</strong> is as if <var>target_task</var> had directly
  45 written into the set of
  46 pages.  Hence, <var>target_task</var> must have write permission to the pages.
  47 <h3>NOTES</h3>
  48 <p>
  49 This interface is machine word length specific because of the virtual address
  50 parameter.
  51 <h3>RETURN VALUES</h3>
  52 <dl>
  53 <p>
  54 <dt> <strong>KERN_PROTECTION_FAILURE</strong>
  55 <dd>
  56 Specified memory is valid, but does not permit writing.
  57 <p>
  58 <dt> <strong>KERN_INVALID_ADDRESS</strong>
  59 <dd>
  60 The address is illegal or specifies a non-allocated region.
  61 </dl>
  62 <h3>RELATED INFORMATION</h3>
  63 <p>
  64 Functions:
  65 <a href="vm_copy.html"><strong>vm_copy</strong></a>,
  66 <a href="vm_protect.html"><strong>vm_protect</strong></a>,
  67 <a href="vm_read.html"><strong>vm_read</strong></a>,
  68 <a href="host_page_size.html"><strong>host_page_size</strong></a>.