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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