1.\" 2.\" Copyright (c) 2003 Bruce M Simpson <bms@spc.org> 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24.\" SUCH DAMAGE. 25.\" 26.\" $FreeBSD$ 27.\" 28.Dd July 19, 2003 29.Dt vm_map_stack 9 30.Sh NAME 31.Nm vm_map_stack , 32.Nm vm_map_growstack 33.Nd manage process stacks 34.Sh SYNOPSIS 35.In sys/param.h 36.In vm/vm.h 37.In vm/vm_map.h 38.Ft int 39.Fn vm_map_stack "vm_map_t map" "vm_offset_t addrbos" "vm_size_t max_ssize" "vm_prot_t prot" "vm_prot_t max" "int cow" 40.Ft int 41.Fn vm_map_growstack "struct proc *p" "vm_offset_t addr" 42.Sh DESCRIPTION 43The 44.Fn 45function maps a process stack for a new process image. 46The stack is mapped 47.Fa addrbos 48in 49.Fa map , 50with a maximum size of 51.Fa max_ssize . 52Copy-on-write flags passed in 53.Fa cow 54are also applied to the new mapping. 55Protection bits are supplied by 56.Fa prot 57and 58.Fa max . 59.Pp 60It is typically called by 61.Xr exec 2 . 62.Pp 63The 64.Fn vm_map_growstack 65function is responsible for growing a stack for the process 66.Fa p 67to the desired address 68.Fa addr , 69similar to the legacy 70.Xr sbrk 2 71call. 72.Sh IMPLEMENTATION NOTES 73The 74.Fn vm_map_stack 75function calls 76.Xr vm_map_insert 9 77to create its mappings. 78.Pp 79The 80.Fn vm_map_growstack 81function acquires the 82.Dv Giant 83lock, and the process lock on 84.Fa p , 85for the duration of the call. 86.Sh RETURN VALUES 87The 88.Fn vm_map_stack 89function returns 90.Dv KERN_SUCCESS 91if the mapping was allocated successfully. 92.Pp 93Otherwise, 94if mapping the stack would exceed the process's VMEM resource limit, 95or if the specified bottom-of-stack address is out of range for the map, 96or if there is already a mapping at the address which would result, 97or if 98.Fa max_ssize 99could not be accomodated within the current mapping, 100.Dv KERN_NO_SPACE 101is returned. 102.Pp 103Other possible return values for this function are documented in 104.Xr vm_map_insert 9 . 105.Pp 106The 107.Fn vm_map_growstack 108function returns 109.Dv KERN_SUCCESS 110if 111.Fa addr 112is already mapped, or if the stack was grown successfully. 113.Pp 114It also returns 115.Dv KERN_SUCCESS 116if 117.Fa addr 118is outside the stack range; this is done in order to preserve 119compatibility with the deprecated 120.Fn grow 121function previously located in the file 122.Li vm_machdep.c . 123.Sh SEE ALSO 124.Xr vm_map 9 , 125.Xr vm_map_insert 9 126.Sh AUTHORS 127This man page was written by 128.An Bruce M Simpson Aq bms@spc.org . 129