base-files: set ptmxmode to 666

Make sure that the (newer) /dev/pts/ptmx is accessible by users. This
is useful e.g. when running containers which symlink /dev/ptmx to
/dev/pts/ptmx on start. The default mode (000) does not allow to
create ptys inside the container.

Using 666 when symlinking /dev/ptmx is also recommended by the kernel
documentation when /dev/ptmx is symlinked:
https://www.kernel.org/doc/Documentation/filesystems/devpts.txt

Also buildroot uses ptmxmode=0666. The patch introducing the change
explains related use cases why this is necessary a bit more in depth:
https://github.com/buildroot/buildroot/commit/8196b299ba12bd6741bf7f4462cad180dab77fb0#diff-2d4604b9e565eb19fa52ce31f282f06c

Signed-off-by: Stefan Agner <stefan.agner@toradex.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

diff --git a/meta/recipes-core/base-files/base-files/fstab b/meta/recipes-core/base-files/base-files/fstab
index d79a01602f561d0b52cad24bccf53e23b436ff97..70e400f567433e7bf8eddb492e7676607de53641 100644 (file)
--- a/meta/recipes-core/base-files/base-files/fstab
+++ b/meta/recipes-core/base-files/base-files/fstab
@@ -2,7 +2,7 @@
 
 /dev/root            /                    auto       defaults              1  1
 proc                 /proc                proc       defaults              0  0
-devpts               /dev/pts             devpts     mode=0620,gid=5       0  0
+devpts               /dev/pts             devpts     mode=0620,ptmxmode=0666,gid=5      0  0
 tmpfs                /run                 tmpfs      mode=0755,nodev,nosuid,strictatime 0  0
 tmpfs                /var/volatile        tmpfs      defaults              0  0