Make the mincore(2) return ENOMEM when requested range is not fully mapped.

Requested by:	Bruno Haible <bruno at clisp org>
Reviewed by:	alc
Approved by:	pjd (mentor)
MFC after:	1 month

2 files changed, 17 insertions, 5 deletions

diff --git a/lib/libc/sys/mincore.2 b/lib/libc/sys/mincore.2
index 25ad076..75e74a4 100644
--- a/lib/libc/sys/mincore.2
+++ b/lib/libc/sys/mincore.2
@@ -92,12 +92,12 @@ The
 .Fn mincore
 system call will fail if:
 .Bl -tag -width Er
-.It Bq Er EINVAL
+.It Bq Er ENOMEM
 The virtual address range specified by the
 .Fa addr
 and
 .Fa len
-arguments is not valid.
+arguments is not fully mapped.
 .It Bq Er EFAULT
 The
 .Fa vec
diff --git a/sys/vm/vm_mmap.c b/sys/vm/vm_mmap.c
index 5965d4a..244877e 100644
--- a/sys/vm/vm_mmap.c
+++ b/sys/vm/vm_mmap.c
@@ -757,7 +757,7 @@ mincore(td, uap)
 	end = addr + (vm_size_t)round_page(uap->len);
 	map = &td->td_proc->p_vmspace->vm_map;
 	if (end > vm_map_max(map) || end < addr)
-		return (EINVAL);
+		return (ENOMEM);
 
 	/*
 	 * Address of byte vector
@@ -770,8 +770,10 @@ mincore(td, uap)
 RestartScan:
 	timestamp = map->timestamp;
 
-	if (!vm_map_lookup_entry(map, addr, &entry))
-		entry = entry->next;
+	if (!vm_map_lookup_entry(map, addr, &entry)) {
+		vm_map_unlock_read(map);
+		return (ENOMEM);
+	}
 
 	/*
 	 * Do this on a map entry basis so that if the pages are not
@@ -784,6 +786,16 @@ RestartScan:
 	    current = current->next) {
 
 		/*
+		 * check for contiguity
+		 */
+		if (current->end < end &&
+		    (entry->next == &map->header ||
+		     current->next->start > current->end)) {
+			vm_map_unlock_read(map);
+			return (ENOMEM);
+		}
+
+		/*
 		 * ignore submaps (for now) or null objects
 		 */
 		if ((current->eflags & MAP_ENTRY_IS_SUB_MAP) ||