1 files changed, 85 insertions, 4 deletions

diff --git a/sys/kern/kern_exec.c b/sys/kern/kern_exec.c
index 1e4d690..6cf77f7 100644
--- a/sys/kern/kern_exec.c
+++ b/sys/kern/kern_exec.c
@@ -389,6 +389,7 @@ do_execve(td, args, mac_p)
 	imgp->canarylen = 0;
 	imgp->pagesizes = 0;
 	imgp->pagesizeslen = 0;
+	imgp->stack_prot = 0;
 
 #ifdef MAC
 	error = mac_execve_enter(imgp, mac_p);
@@ -996,6 +997,7 @@ exec_new_vmspace(imgp, sv)
 	int error;
 	struct proc *p = imgp->proc;
 	struct vmspace *vmspace = p->p_vmspace;
+	vm_object_t obj;
 	vm_offset_t sv_minuser, stack_addr;
 	vm_map_t map;
 	u_long ssiz;
@@ -1029,6 +1031,20 @@ exec_new_vmspace(imgp, sv)
 		map = &vmspace->vm_map;
 	}
 
+	/* Map a shared page */
+	obj = sv->sv_shared_page_obj;
+	if (obj != NULL) {
+		vm_object_reference(obj);
+		error = vm_map_fixed(map, obj, 0,
+		    sv->sv_shared_page_base, sv->sv_shared_page_len,
+		    VM_PROT_READ | VM_PROT_EXECUTE, VM_PROT_ALL,
+		    MAP_COPY_ON_WRITE | MAP_ACC_NO_CHARGE);
+		if (error) {
+			vm_object_deallocate(obj);
+			return (error);
+		}
+	}
+
 	/* Allocate a new stack */
 	if (sv->sv_maxssiz != NULL)
 		ssiz = *sv->sv_maxssiz;
@@ -1036,7 +1052,9 @@ exec_new_vmspace(imgp, sv)
 		ssiz = maxssiz;
 	stack_addr = sv->sv_usrstack - ssiz;
 	error = vm_map_stack(map, stack_addr, (vm_size_t)ssiz,
-	    sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_DOWN);
+	    obj != NULL && imgp->stack_prot != 0 ? imgp->stack_prot :
+		sv->sv_stackprot,
+	    VM_PROT_ALL, MAP_STACK_GROWS_DOWN);
 	if (error)
 		return (error);
 
@@ -1208,8 +1226,10 @@ exec_copyout_strings(imgp)
 	p = imgp->proc;
 	szsigcode = 0;
 	arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings;
-	if (p->p_sysent->sv_szsigcode != NULL)
-		szsigcode = *(p->p_sysent->sv_szsigcode);
+	if (p->p_sysent->sv_sigcode_base == 0) {
+		if (p->p_sysent->sv_szsigcode != NULL)
+			szsigcode = *(p->p_sysent->sv_szsigcode);
+	}
 	destp =	(caddr_t)arginfo - szsigcode - SPARE_USRSPACE -
 	    roundup(execpath_len, sizeof(char *)) -
 	    roundup(sizeof(canary), sizeof(char *)) -
@@ -1219,7 +1239,7 @@ exec_copyout_strings(imgp)
 	/*
 	 * install sigcode
 	 */
-	if (szsigcode)
+	if (szsigcode != 0)
 		copyout(p->p_sysent->sv_sigcode, ((caddr_t)arginfo -
 		    szsigcode), szsigcode);
 
@@ -1459,3 +1479,64 @@ exec_unregister(execsw_arg)
 	execsw = newexecsw;
 	return (0);
 }
+
+static vm_object_t shared_page_obj;
+static int shared_page_free;
+
+int
+shared_page_fill(int size, int align, const char *data)
+{
+	vm_page_t m;
+	struct sf_buf *s;
+	vm_offset_t sk;
+	int res;
+
+	VM_OBJECT_LOCK(shared_page_obj);
+	m = vm_page_grab(shared_page_obj, 0, VM_ALLOC_RETRY);
+	res = roundup(shared_page_free, align);
+	if (res + size >= IDX_TO_OFF(shared_page_obj->size))
+		res = -1;
+	else {
+		VM_OBJECT_UNLOCK(shared_page_obj);
+		s = sf_buf_alloc(m, SFB_DEFAULT);
+		sk = sf_buf_kva(s);
+		bcopy(data, (void *)(sk + res), size);
+		shared_page_free = res + size;
+		sf_buf_free(s);
+		VM_OBJECT_LOCK(shared_page_obj);
+	}
+	vm_page_wakeup(m);
+	VM_OBJECT_UNLOCK(shared_page_obj);
+	return (res);
+}
+
+static void
+shared_page_init(void *dummy __unused)
+{
+	vm_page_t m;
+
+	shared_page_obj = vm_pager_allocate(OBJT_PHYS, 0, PAGE_SIZE,
+	    VM_PROT_DEFAULT, 0, NULL);
+	VM_OBJECT_LOCK(shared_page_obj);
+	m = vm_page_grab(shared_page_obj, 0, VM_ALLOC_RETRY | VM_ALLOC_NOBUSY |
+	    VM_ALLOC_ZERO);
+	m->valid = VM_PAGE_BITS_ALL;
+	VM_OBJECT_UNLOCK(shared_page_obj);
+}
+
+SYSINIT(shp, SI_SUB_EXEC, SI_ORDER_FIRST, (sysinit_cfunc_t)shared_page_init,
+    NULL);
+
+void
+exec_sysvec_init(void *param)
+{
+	struct sysentvec *sv;
+
+	sv = (struct sysentvec *)param;
+
+	if ((sv->sv_flags & SV_SHP) == 0)
+		return;
+	sv->sv_shared_page_obj = shared_page_obj;
+	sv->sv_sigcode_base = sv->sv_shared_page_base +
+	    shared_page_fill(*(sv->sv_szsigcode), 16, sv->sv_sigcode);
+}