projects / apple / libpthread.git / blame
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1 | .\" Copyright (c) 2020 Apple Inc. All rights reserved. |
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| 5 | .\" This file contains Original Code and/or Modifications of Original Code | |
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| 21 | .\" | |
| 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 |