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authorespie <espie@openbsd.org>2001-08-03 19:44:21 +0000
committerespie <espie@openbsd.org>2001-08-03 19:44:21 +0000
commit2ba92bc64a44752f50bb615cb725026605b3ec49 (patch)
treec8ccd29688df20c391e1f7086874c2c9fe3ad4a6 /lib/libc
parento Fix sectok_apdu() proto (diff)
downloadwireguard-openbsd-2ba92bc64a44752f50bb615cb725026605b3ec49.tar.xz
wireguard-openbsd-2ba92bc64a44752f50bb615cb725026605b3ec49.zip
Acknowledge VM's limitations.
Diffstat (limited to 'lib/libc')
-rw-r--r--lib/libc/sys/mmap.215
1 files changed, 14 insertions, 1 deletions
diff --git a/lib/libc/sys/mmap.2 b/lib/libc/sys/mmap.2
index e9a15ad530d..8c057b230eb 100644
--- a/lib/libc/sys/mmap.2
+++ b/lib/libc/sys/mmap.2
@@ -1,4 +1,4 @@
-.\" $OpenBSD: mmap.2,v 1.22 2001/05/11 14:54:25 art Exp $
+.\" $OpenBSD: mmap.2,v 1.23 2001/08/03 19:44:21 espie Exp $
.\" $NetBSD: mmap.2,v 1.5 1995/06/24 10:48:59 cgd Exp $
.\"
.\" Copyright (c) 1991, 1993
@@ -217,6 +217,19 @@ parameter wasn't available.
.Dv MAP_ANON
was specified and insufficient memory was available.
.El
+.Sh BUGS
+Due to a limitation of the current vm system (see
+.Xr uvm 9 ),
+mapping descriptors
+.Dv PROT_WRITE
+without also specifying
+.Dv PROT_READ
+is useless
+(results in a segmentation fault when first accessing the mapping).
+This means that such descriptors must be opened with
+.Dv O_RDWR ,
+for which you need both read and write permissions on the underlying
+object.
.Sh SEE ALSO
.Xr madvise 2 ,
.Xr mincore 2 ,