vm_map_stack(9)

NAME

vm_map_stack, vm_map_growstack - manage process stacks

SYNOPSIS

#include <sys/param.h>
#include <vm/vm.h>
#include <vm/vm_map.h>
int
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);
int
vm_map_growstack(struct proc *p, vm_offset_t addr);

DESCRIPTION

The vm_map_stack() function maps a process stack for a new

process image.
The stack is mapped addrbos in map, with a maximum size of

max_ssize.
Copy-on-write flags passed in cow are also applied to the

new mapping.
Protection bits are supplied by prot and max.

It is typically called by execve(2).

The vm_map_growstack() function is responsible for growing a

stack for
the process p to the desired address addr, similar to the

legacy sbrk(2)
call.

IMPLEMENTATION NOTES

The vm_map_stack() function calls vm_map_insert(9) to create

its mappings.

The vm_map_growstack() function acquires the Giant lock, and

the process
lock on p, for the duration of the call.

RETURN VALUES

The vm_map_stack() function returns KERN_SUCCESS if the map

ping was allocated successfully.

Otherwise, if mapping the stack would exceed the process's

VMEM resource
limit, or if the specified bottom-of-stack address is out of

range for
the map, or if there is already a mapping at the address

which would
result, or if max_ssize could not be accomodated within the

current mapping, KERN_NO_SPACE is returned.

Other possible return values for this function are document

ed in
vm_map_insert(9).

The vm_map_growstack() function returns KERN_SUCCESS if addr

is already
mapped, or if the stack was grown successfully.

It also returns KERN_SUCCESS if addr is outside the stack

range; this is
done in order to preserve compatibility with the deprecated

grow() function previously located in the file vm_machdep.c.

SEE ALSO

vm_map(9), vm_map_insert(9)

AUTHORS

This manual page was written by Bruce M Simpson

<bms@spc.org>.

BSD July 19, 2003

BSD