From: Sukadev Bhattiprolu <sukadev@xxxxxxxxxxxxxxxxxx> Date: Thu, 15 Jan 2009 22:41:42 -0800 Subject: [PATCH] Document newinstance and ptmxmode options to devpts Support for multiple instances of devpts were included in 2.6.29-rc1. Update man pages to document the new options. Additional details about the new options are described in 'Documentation/filesystems/devpts.txt' of kernel source tree. TODO: - If devpts(4) options are described in a separate man page, base this patch on that source. Until then leave this text in mount(8) ? Changelog[v2]: - Fix a typo (Americo Wang) - Remove some duplication (Serge Hallyn) Signed-off-by: Sukadev Bhattiprolu <sukadev@xxxxxxxxxxxxxxxxxx> --- mount/mount.8 | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 55 insertions(+), 0 deletions(-) diff --git a/mount/mount.8 b/mount/mount.8 index 956e10f..53d9fe9 100644 --- a/mount/mount.8 +++ b/mount/mount.8 @@ -991,6 +991,61 @@ A value of and .B gid=5 makes "mesg y" the default on newly created PTYs. +.TP +\fBnewinstance +Create a private instance of devpts filesystem, such that +indices of ptys allocated in this new instance are +independent of indices created in other instances of devpts. + +All mounts of devpts without this +.B newinstance +option share the same set of pty indices (i.e legacy mode). +Each mount of devpts with +.B newinstance +option has a private set of pty indices. + +This option is mainly used to support containers in the +linux kernel. It is implemented in linux kernel versions +starting with 2.6.29. Further, this mount option is valid +only if CONFIG_DEVPTS_MULTIPLE_INSTANCES is enabled in the +kernel configuration. + +To use this option effectively, +.IR /dev/ptmx +must be a symbolic link to +.IR pts/ptmx. +See +.IR Documentation/filesystems/devpts.txt +in the linux kernel source tree for details. +.TP +.BI ptmxmode= value + +Set the mode for the new +.IR ptmx +device node in the devpts filesystem. + +With support for multiple instances of devpts (see +.B newinstance +option above), each instance has a private +.IR ptmx +node in the root of the devpts filesystem (typically +.IR /dev/pts/ptmx). + +For compatibility with older versions of the kernel, the +default mode of the new +.IR ptmx +node is 0000. +.BI ptmxmode= value +specifies a more useful mode for the +.IR ptmx +node and is highly recommended when the +.B newinstance +option is specified. + +This option is only implemented in linux kernel versions +starting with 2.6.29. Further this option is valid only if +CONFIG_DEVPTS_MULTIPLE_INSTANCES is enabled in the kernel +configuration. .SH "Mount options for ext" None. -- To unsubscribe from this list: send the line "unsubscribe util-linux-ng" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
