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Clarify wording for terminal setting and /dev/console #518

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hqhq merged 1 commit into from
Nov 7, 2016
Merged

Clarify wording for terminal setting and /dev/console #518

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2 changes: 1 addition & 1 deletion config-linux.md
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Expand Up @@ -148,7 +148,7 @@ In addition to any devices configured with this setting, the runtime MUST also s
* [`/dev/random`][random.4]
* [`/dev/urandom`][random.4]
* [`/dev/tty`][tty.4]
* [`/dev/console`][console.4]
* [`/dev/console`][console.4] is setup if terminal is enabled in the config by bind mounting the pseudoterminal slave to /dev/console.
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@wking wking Aug 17, 2016

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I still think:

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@cyphar cyphar Sep 29, 2016

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We don't want to require bind-mounting the slave over this. Let the runtime point /dev/console to a place it considers appropriate for logging system messages, which may not be the pseudoterminal slave. In fact, I'd expect the validation for /dev/console to be “Is the major 5, the minor 1, and the type ‘char’?”, which is not going to be satisfied by bind-mounting the slave.

That validation does not work inside containers. That particular major and minor number is reserved for consoles that are created as part of initial bootup (think physical console) on Linux. I think that it is entirely sufficient to just state that /dev/console should be a valid place to log system messages (which is what you suggested).

* [`/dev/ptmx`][pts.4].
A [bind-mount or symlink of the container's `/dev/pts/ptmx`][devpts].

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4 changes: 3 additions & 1 deletion config.md
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Expand Up @@ -94,7 +94,8 @@ See links for details about [mountvol](http://ss64.com/nt/mountvol.html) and [Se

**`process`** (object, REQUIRED) configures the container process.

* **`terminal`** (bool, OPTIONAL) specifies whether you want a terminal attached to that process, defaults to false.
* **`terminal`** (bool, optional) specifies whether a terminal is attached to that process, defaults to false.
On Linux, a pseudoterminal pair is allocated for the container process and the pseudoterminal slave is duplicated on the container process's [standard streams][stdin.3].
* **`consoleSize`** (object, OPTIONAL) specifies the console size of the terminal if attached, containing the following properties:
* **`height`** (uint, REQUIRED)
* **`width`** (uint, REQUIRED)
Expand Down Expand Up @@ -744,3 +745,4 @@ Here is a full example `config.json` for reference.
[mount.8-filesystem-independent]: http://man7.org/linux/man-pages/man8/mount.8.html#FILESYSTEM-INDEPENDENT_MOUNT%20OPTIONS
[mount.8-filesystem-specific]: http://man7.org/linux/man-pages/man8/mount.8.html#FILESYSTEM-SPECIFIC_MOUNT%20OPTIONS
[mount.8]: http://man7.org/linux/man-pages/man8/mount.8.html
[stdin.3]: http://man7.org/linux/man-pages/man3/stdin.3.html