NAME    [Toc]    [Back]

     vm_map_stack, vm_map_growstack -- manage process stacks

SYNOPSIS    [Toc]    [Back]

     #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    [Toc]    [Back]

     The 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 exec(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    [Toc]    [Back]

     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    [Toc]    [Back]

     The vm_map_stack() function returns KERN_SUCCESS if the mapping 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 documented 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    [Toc]    [Back]

     vm_map(9), vm_map_insert(9)

AUTHORS    [Toc]    [Back]

     This man page was written by Bruce M Simpson <bms@spc.org>.


				 July 19, 2003