1.\" 2.\" Copyright (c) 2003 Bruce M Simpson <[email protected]> 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.Fo vm_map_stack 40.Fa "vm_map_t map" "vm_offset_t addrbos" "vm_size_t max_ssize" "vm_prot_t prot" 41.Fa "vm_prot_t max" "int cow" 42.Fc 43.Ft int 44.Fn vm_map_growstack "struct proc *p" "vm_offset_t addr" 45.Sh DESCRIPTION 46The 47.Fn vm_map_stack 48function maps a process stack for a new process image. 49The stack is mapped 50.Fa addrbos 51in 52.Fa map , 53with a maximum size of 54.Fa max_ssize . 55Copy-on-write flags passed in 56.Fa cow 57are also applied to the new mapping. 58Protection bits are supplied by 59.Fa prot 60and 61.Fa max . 62.Pp 63It is typically called by 64.Xr execve 2 . 65.Pp 66The 67.Fn vm_map_growstack 68function is responsible for growing a stack for the process 69.Fa p 70to the desired address 71.Fa addr , 72similar to the legacy 73.Xr sbrk 2 74call. 75.Sh IMPLEMENTATION NOTES 76The 77.Fn vm_map_stack 78function calls 79.Xr vm_map_insert 9 80to create its mappings. 81.Pp 82The 83.Fn vm_map_growstack 84function acquires the 85.Va Giant 86lock, and the process lock on 87.Fa p , 88for the duration of the call. 89.Sh RETURN VALUES 90The 91.Fn vm_map_stack 92function returns 93.Dv KERN_SUCCESS 94if the mapping was allocated successfully. 95.Pp 96Otherwise, 97if mapping the stack would exceed the process's VMEM resource limit, 98or if the specified bottom-of-stack address is out of range for the map, 99or if there is already a mapping at the address which would result, 100or if 101.Fa max_ssize 102could not be accomodated within the current mapping, 103.Dv KERN_NO_SPACE 104is returned. 105.Pp 106Other possible return values for this function are documented in 107.Xr vm_map_insert 9 . 108.Pp 109The 110.Fn vm_map_growstack 111function returns 112.Dv KERN_SUCCESS 113if 114.Fa addr 115is already mapped, or if the stack was grown successfully. 116.Pp 117It also returns 118.Dv KERN_SUCCESS 119if 120.Fa addr 121is outside the stack range; this is done in order to preserve 122compatibility with the deprecated 123.Fn grow 124function previously located in the file 125.Pa vm_machdep.c . 126.Sh SEE ALSO 127.Xr vm_map 9 , 128.Xr vm_map_insert 9 129.Sh AUTHORS 130This man page was written by 131.An Bruce M Simpson Aq [email protected] . 132