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| 23 | .\" |
| 24 | .\" $NetBSD: mprotect.2,v 1.6 1995/10/12 15:41:08 jtc Exp $ |
| 25 | .\" |
| 26 | .\" Copyright (c) 1991, 1993 |
| 27 | .\" The Regents of the University of California. All rights reserved. |
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| 34 | .\" 2. Redistributions in binary form must reproduce the above copyright |
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| 57 | .\" @(#)mprotect.2 8.1 (Berkeley) 6/9/93 |
| 58 | .\" $FreeBSD: src/lib/libc/sys/mprotect.2,v 1.18 2007/01/09 00:28:15 imp Exp $ |
| 59 | .\" |
| 60 | .Dd October 16, 2008 |
| 61 | .Dt MPROTECT 2 |
| 62 | .Os |
| 63 | .Sh NAME |
| 64 | .Nm mprotect |
| 65 | .Nd control the protection of pages |
| 66 | .Sh SYNOPSIS |
| 67 | .Fd #include <sys/mman.h> |
| 68 | .Ft int |
| 69 | .Fo mprotect |
| 70 | .Fa "void *addr" |
| 71 | .Fa "size_t len" |
| 72 | .Fa "int prot" |
| 73 | .Fc |
| 74 | .Sh DESCRIPTION |
| 75 | The |
| 76 | .Fn mprotect |
| 77 | system call |
| 78 | changes the specified pages to have protection |
| 79 | .Fa prot . |
| 80 | Not all implementations will guarantee protection on a page basis but Mac OS X's |
| 81 | current implementation does. |
| 82 | .Pp |
| 83 | When a program violates the protections of a page, it gets a SIGBUS or SIGSEGV signal. |
| 84 | .Pp |
| 85 | Currently |
| 86 | .Fa prot |
| 87 | can be one or more of the following: |
| 88 | .Pp |
| 89 | .Bl -tag -width ".Dv PROT_WRITE" -compact |
| 90 | .It Dv PROT_NONE |
| 91 | No permissions at all. |
| 92 | .It Dv PROT_READ |
| 93 | The pages can be read. |
| 94 | .It Dv PROT_WRITE |
| 95 | The pages can be written. |
| 96 | .It Dv PROT_EXEC |
| 97 | The pages can be executed. |
| 98 | .El |
| 99 | .Sh RETURN VALUES |
| 100 | Upon successful completion, |
| 101 | a value of 0 is returned. |
| 102 | Otherwise, a value of -1 is returned and |
| 103 | .Va errno |
| 104 | is set to indicate the error. |
| 105 | .Sh ERRORS |
| 106 | .Fn mprotect |
| 107 | will fail if: |
| 108 | .Bl -tag -width Er |
| 109 | .\" =========== |
| 110 | .It Bq Er EACCES |
| 111 | The requested protection conflicts with |
| 112 | the access permissions of the process |
| 113 | on the specified address range. |
| 114 | .\" =========== |
| 115 | .\" .It Bq Er EAGAIN |
| 116 | .\" Insufficient memory resources exist to allow locking a private page |
| 117 | .\" under PROT_WRITE. |
| 118 | .\" =========== |
| 119 | .It Bq Er EINVAL |
| 120 | .Fa addr |
| 121 | is not a multiple of the page size (i.e. |
| 122 | .Fa addr |
| 123 | is not page-aligned). |
| 124 | .\" =========== |
| 125 | .\" .It Bq Er ENOMEM |
| 126 | .\" The specified address range is outside of the address range |
| 127 | .\" of the process or includes an unmapped page. |
| 128 | .\" =========== |
| 129 | .It Bq Er ENOTSUP |
| 130 | The combination of accesses requested in |
| 131 | .Fa prot |
| 132 | is not supported. |
| 133 | .El |
| 134 | .Sh LEGACY SYNOPSIS |
| 135 | .Fd #include <sys/types.h> |
| 136 | .Fd #include <sys/mman.h> |
| 137 | .Pp |
| 138 | The include file |
| 139 | .In sys/types.h |
| 140 | is necessary. |
| 141 | .Pp |
| 142 | .Ft int |
| 143 | .br |
| 144 | .Fo mprotect |
| 145 | .Fa "caddr_t addr" |
| 146 | .Fa "size_t len" |
| 147 | .Fa "int prot" |
| 148 | .Fc ; |
| 149 | .Pp |
| 150 | The type of |
| 151 | .Fa addr |
| 152 | has changed. |
| 153 | .Sh SEE ALSO |
| 154 | .Xr madvise 2 , |
| 155 | .Xr mincore 2 , |
| 156 | .Xr msync 2 , |
| 157 | .Xr munmap 2 , |
| 158 | .Xr compat 5 |
| 159 | .Sh HISTORY |
| 160 | The |
| 161 | .Fn mprotect |
| 162 | function first appeared in 4.4BSD. |