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Allow a kernel-supported process thread to do an exec without blasting

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away the VM space of all of the other, associated threads.
This commit is contained in:
John Dyson 1997-04-11 23:37:23 +00:00
parent 8253a7d685
commit af9ec88589
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=24828
1 changed files with 24 additions and 7 deletions
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31
sys/kern/kern_exec.c
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@ -23,7 +23,7 @@
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id: kern_exec.c,v 1.56 1997/04/04 07:30:06 davidg Exp $
* $Id: kern_exec.c,v 1.57 1997/04/04 09:06:20 davidg Exp $
*/
#include <sys/param.h>
@ -369,17 +369,34 @@ exec_new_vmspace(imgp)
int error;
struct vmspace *vmspace = imgp->proc->p_vmspace;
caddr_t stack_addr = (caddr_t) (USRSTACK - SGROWSIZ);
vm_map_t map = &vmspace->vm_map;
imgp->vmspace_destroyed = 1;
/* Blow away entire process VM */
if (vmspace->vm_shm)
shmexit(imgp->proc);
pmap_remove_pages(&vmspace->vm_pmap, 0, USRSTACK);
vm_map_remove(&vmspace->vm_map, 0, USRSTACK);
/*
* Blow away entire process VM, if address space not shared,
* otherwise, create a new VM space so that other threads are
* not disrupted
*/
if (vmspace->vm_refcnt == 1) {
if (vmspace->vm_shm)
shmexit(imgp->proc);
pmap_remove_pages(&vmspace->vm_pmap, 0, USRSTACK);
vm_map_remove(map, 0, USRSTACK);
} else {
struct vmspace *oldvmspace = vmspace;
--vmspace->vm_refcnt;
vmspace = vmspace_alloc(map->min_offset, map->max_offset,
map->entries_pageable);
bcopy(&oldvmspace->vm_startcopy, &vmspace->vm_startcopy,
(caddr_t) (vmspace+ 1) - (caddr_t) &vmspace->vm_startcopy);
imgp->proc->p_vmspace = vmspace;
map = &vmspace->vm_map;
}
/* Allocate a new stack */
error = vm_map_find(&vmspace->vm_map, NULL, 0, (vm_offset_t *)&stack_addr,
error = vm_map_find(map, NULL, 0, (vm_offset_t *)&stack_addr,
SGROWSIZ, FALSE, VM_PROT_ALL, VM_PROT_ALL, 0);
if (error)
return(error);