e604fa387c
While here, document that the process lock is acquired in vm_map_stack, too. MFC after: 1 week
133 lines
3.5 KiB
Groff
133 lines
3.5 KiB
Groff
.\"
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.\" Copyright (c) 2003 Bruce M Simpson <bms@spc.org>
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd January 11, 2013
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.Dt VM_MAP_STACK 9
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.Os
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.Sh NAME
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.Nm vm_map_stack ,
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.Nm vm_map_growstack
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.Nd manage process stacks
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.Sh SYNOPSIS
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.In sys/param.h
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.In vm/vm.h
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.In vm/vm_map.h
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.Ft int
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.Fo vm_map_stack
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.Fa "vm_map_t map" "vm_offset_t addrbos" "vm_size_t max_ssize" "vm_prot_t prot"
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.Fa "vm_prot_t max" "int cow"
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.Fc
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.Ft int
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.Fn vm_map_growstack "struct proc *p" "vm_offset_t addr"
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.Sh DESCRIPTION
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The
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.Fn vm_map_stack
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function maps a process stack for a new process image.
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The stack is mapped
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.Fa addrbos
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in
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.Fa map ,
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with a maximum size of
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.Fa max_ssize .
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Copy-on-write flags passed in
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.Fa cow
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are also applied to the new mapping.
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Protection bits are supplied by
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.Fa prot
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and
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.Fa max .
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.Pp
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It is typically called by
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.Xr execve 2 .
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.Pp
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The
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.Fn vm_map_growstack
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function is responsible for growing a stack for the process
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.Fa p
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to the desired address
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.Fa addr ,
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similar to the legacy
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.Xr sbrk 2
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call.
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.Sh IMPLEMENTATION NOTES
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The
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.Fn vm_map_stack
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function calls
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.Xr vm_map_insert 9
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to create its mappings.
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.Pp
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The
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.Fn vm_map_stack
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and
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.Fn vm_map_growstack
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functions acquire the process lock on
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.Fa p
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for the duration of the call.
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.Sh RETURN VALUES
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The
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.Fn vm_map_stack
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function returns
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.Dv KERN_SUCCESS
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if the mapping was allocated successfully.
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.Pp
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Otherwise,
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if mapping the stack would exceed the process's VMEM resource limit,
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or if the specified bottom-of-stack address is out of range for the map,
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or if there is already a mapping at the address which would result,
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or if
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.Fa max_ssize
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could not be accommodated within the current mapping,
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.Dv KERN_NO_SPACE
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is returned.
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.Pp
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Other possible return values for this function are documented in
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.Xr vm_map_insert 9 .
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.Pp
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The
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.Fn vm_map_growstack
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function returns
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.Dv KERN_SUCCESS
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if
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.Fa addr
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is already mapped, or if the stack was grown successfully.
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.Pp
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It also returns
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.Dv KERN_SUCCESS
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if
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.Fa addr
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is outside the stack range; this is done in order to preserve
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compatibility with the deprecated
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.Fn grow
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function previously located in the file
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.Pa vm_machdep.c .
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.Sh SEE ALSO
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.Xr vm_map 9 ,
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.Xr vm_map_insert 9
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.Sh AUTHORS
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This manual page was written by
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.An Bruce M Simpson Aq bms@spc.org .
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