man/pthread_jit_write_protect_np.3

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  22 .Dd May 1, 2020
  23 .Dt PTHREAD_JIT_WRITE_PROTECT_NP 3
  24 .Os
  25 .Sh NAME
  26 .Nm pthread_jit_write_protect_supported_np ,
  27 .Nm pthread_jit_write_protect_np
  28 .Nd thread JIT region write protection settings
  29 .Sh SYNOPSIS
  30 .In pthread.h
  31 .Ft int
  32 .Fn pthread_jit_write_protect_supported_np "void"
  33 .Ft void
  34 .Fn pthread_jit_write_protect_np "int enabled"
  35 .Sh DESCRIPTION
  36 The
  37 .Fn pthread_jit_write_protect_supported_np
  38 function returns whether the
  39 .Fn pthread_jit_write_protect_np
  40 API is supported on this platform. If
  41 .Fn pthread_jit_write_protect_np
  42 API is supported on this platform,
  43 .Fn pthread_jit_write_protect_np
  44 must be called to toggle per-thread write protection on the MAP_JIT region before the thread writes to or executes from the MAP_JIT region.
  45 .Pp
  46 The
  47 .Fn pthread_jit_write_protect_np
  48 function sets whether MAP_JIT region write protection is enabled for this thread.
  49 .Pp
  50 On platforms where
  51 .Fn pthread_jit_write_protect_supported_np
  52 is true, MAP_JIT regions are never writeable and executable simultaneously.
  53 When write protection is enabled for the thread, writes by the thread to the MAP_JIT region are denied and the MAP_JIT region is executable.
  54 When write protection is disabled for the thread, writes by the thread to the MAP_JIT region are allowed and the MAP_JIT region is not executable.
  55 Pass a non-zero value for the
  56 .Fa enabled
  57 parameter to enable thread JIT region write protection and allow execution. Pass a zero value for the
  58 .Fa enabled
  59 parameter to disable thread JIT write protection and deny execution.
  60 .Pp
  61 On platforms where
  62 .Fn pthread_jit_write_protect_supported_np
  63 is not supported, MAP_JIT regions are both simultaenously writeable and executable. Calls to
  64 .Fn pthread_jit_write_protect_np
  65 are no-ops on unsupported platforms.
  66 .Sh RETURN VALUES
  67 If supported, the
  68 .Fn pthread_jit_write_protect_supported_np
  69 function will return one.  Otherwise the function will return zero.
  70 .Sh SEE ALSO
  71 .Xr mmap 2