From 3bccc0f766d1e99e7bb0fda86328af28446049c0 Mon Sep 17 00:00:00 2001
From: christos <christos@NetBSD.org>
Date: Fri, 25 Jul 2008 17:40:24 +0000
Subject: [PATCH] Handle files with a large number of mappings gracefully.
 Reported by Nicholas Joly.

---
 sys/miscfs/procfs/procfs_map.c | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/sys/miscfs/procfs/procfs_map.c b/sys/miscfs/procfs/procfs_map.c
index b17136fce1aa..2f1d38b2f681 100644
--- a/sys/miscfs/procfs/procfs_map.c
+++ b/sys/miscfs/procfs/procfs_map.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: procfs_map.c,v 1.34 2007/12/15 23:52:00 christos Exp $	*/
+/*	$NetBSD: procfs_map.c,v 1.35 2008/07/25 17:40:24 christos Exp $	*/
 
 /*
  * Copyright (c) 1993
@@ -76,7 +76,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: procfs_map.c,v 1.34 2007/12/15 23:52:00 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: procfs_map.c,v 1.35 2008/07/25 17:40:24 christos Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -92,6 +92,7 @@ __KERNEL_RCSID(0, "$NetBSD: procfs_map.c,v 1.34 2007/12/15 23:52:00 christos Exp
 #include <uvm/uvm.h>
 
 #define BUFFERSIZE (64 * 1024)
+#define MAXBUFFERSIZE (256 * 1024)
 
 /*
  * The map entries can *almost* be read with programs like cat.  However,
@@ -111,7 +112,8 @@ procfs_domap(struct lwp *curl, struct proc *p, struct pfsnode *pfs,
 	struct vmspace *vm;
 	struct vm_map *map;
 	struct vm_map_entry *entry;
-	char *buffer;
+	char *buffer = NULL;
+	size_t bufsize = BUFFERSIZE;
 	char *path;
 	struct vnode *vp;
 	struct vattr va;
@@ -133,7 +135,6 @@ procfs_domap(struct lwp *curl, struct proc *p, struct pfsnode *pfs,
 
 	error = 0;
 
-	buffer = malloc(BUFFERSIZE, M_TEMP, M_WAITOK);
 	if (linuxmode != 0)
 		path = malloc(MAXPATHLEN * 4, M_TEMP, M_WAITOK);
 	else
@@ -145,6 +146,8 @@ procfs_domap(struct lwp *curl, struct proc *p, struct pfsnode *pfs,
 	map = &vm->vm_map;
 	vm_map_lock_read(map);
 
+again:
+	buffer = malloc(bufsize, M_TEMP, M_WAITOK);
 	pos = 0;
 	for (entry = map->header.next; entry != &map->header;
 	    entry = entry->next) {
@@ -195,6 +198,15 @@ procfs_domap(struct lwp *curl, struct proc *p, struct pfsnode *pfs,
 			    entry->inheritance, entry->wired_count,
 			    entry->advice);
 		}
+		if (pos >= bufsize) {
+			bufsize <<= 1;
+			if (bufsize > MAXBUFFERSIZE) {
+				error = ENOMEM;
+				goto out;
+			}
+			free(buffer, M_TEMP);
+			goto again;
+		}
 	}
 
 	vm_map_unlock_read(map);