minix/lib/libc/sys/mprotect.2
Ben Gras 2fe8fb192f Full switch to clang/ELF. Drop ack. Simplify.
There is important information about booting non-ack images in
docs/UPDATING. ack/aout-format images can't be built any more, and
booting clang/ELF-format ones is a little different. Updating to the
new boot monitor is recommended.

Changes in this commit:

	. drop boot monitor -> allowing dropping ack support
	. facility to copy ELF boot files to /boot so that old boot monitor
	  can still boot fairly easily, see UPDATING
	. no more ack-format libraries -> single-case libraries
	. some cleanup of OBJECT_FMT, COMPILER_TYPE, etc cases
	. drop several ack toolchain commands, but not all support
	  commands (e.g. aal is gone but acksize is not yet).
	. a few libc files moved to netbsd libc dir
	. new /bin/date as minix date used code in libc/
	. test compile fix
	. harmonize includes
	. /usr/lib is no longer special: without ack, /usr/lib plays no
	  kind of special bootstrapping role any more and bootstrapping
	  is done exclusively through packages, so releases depend even
	  less on the state of the machine making them now.
	. rename nbsd_lib* to lib*
	. reduce mtree
2012-02-14 14:52:02 +01:00

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Groff

.\" $NetBSD: mprotect.2,v 1.22 2009/01/11 02:46:30 christos Exp $
.\"
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.\" @(#)mprotect.2 8.1 (Berkeley) 6/9/93
.\"
.Dd January 6, 2009
.Dt MPROTECT 2
.Os
.Sh NAME
.Nm mprotect
.Nd control the protection of pages
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In sys/mman.h
.Ft int
.Fn mprotect "void *addr" "size_t len" "int prot"
.Sh DESCRIPTION
The
.Fn mprotect
system call
changes the specified pages to have protection
.Fa prot .
Not all implementations will guarantee protection on a page basis;
the granularity of protection changes may be as large as an entire region.
.Pp
The protections (region accessibility) are specified in the
.Fa prot
argument by
.Tn OR Ns 'ing
the following values:
.Pp
.Bl -tag -width MAP_FIXEDX
.It Dv PROT_EXEC
Pages may be executed.
.It Dv PROT_READ
Pages may be read.
.It Dv PROT_WRITE
Pages may be written.
.It Dv PROT_NONE
No permissions.
.El
.Sh RETURN VALUES
Upon successful completion,
a value of 0 is returned.
Otherwise, a value of \-1 is returned and
.Va errno
is set to indicate the error.
.Sh ERRORS
.Bl -tag -width Er
.It Bq Er EACCES
A memory protection violation occurred, or the
.Dv PROT_EXEC
flag was attempted on pages which belong to a filesystem mounted with the
.Dv NOEXEC
flag.
.It Bq Er EINVAL
An invalid memory range, or invalid parameters were provided.
.It Bq Er ENOMEM
A resource shortage occurred while internally calling
.Fn uvm_map_protect .
.El
.Sh SEE ALSO
.Xr madvise 2 ,
.Xr mincore 2 ,
.Xr msync 2 ,
.Xr munmap 2
.Sh HISTORY
The
.Fn mprotect
function first appeared in
.Bx 4.4 .