Fix type of devices type

Fixes: opencontainers/runc#566

For type rune, we can assign char as 'c' in struct, but after
marshal, it'll be presented as int32. So in json config it needs
to be presented as a number which is not friendly to be identified.

Change it to string so that you can actually write "b", "c" in json
spec and you can easily know what type of device it is.

Signed-off-by: Qiang Huang <[email protected]>

Author: hqhq

config-linux.md

@@ -112,7 +112,7 @@ The runtime may supply them however it likes (with [mknod][mknod.2], by bind mou
 
 The following parameters can be specified:
 
-* **`type`** *(char, required)* - type of device: `c`, `b`, `u` or `p`.
+* **`type`** *(string, required)* - type of device: `c`, `b`, `u` or `p`.
   More info in [mknod(1)][mknod.1].
 * **`path`** *(string, required)* - full path to device inside container.
 * **`major, minor`** *(int64, required unless **`type`** is `p`)* - [major, minor numbers][devices] for the device.
@@ -194,7 +194,7 @@ The runtime MUST apply entries in the listed order.
 The following parameters can be specified:
 
 * **`allow`** *(boolean, required)* - whether the entry is allowed or denied.
-* **`type`** *(char, optional)* - type of device: `a` (all), `c` (char), or `b` (block).
+* **`type`** *(string, optional)* - type of device: `a` (all), `c` (char), or `b` (block).
   `null` or unset values mean "all", mapping to `a`.
 * **`major, minor`** *(int64, optional)* - [major, minor numbers][devices] for the device.
   `null` or unset values mean "all", mapping to [`*` in the filesystem API][cgroup-v1-devices].

config_linux.go

@@ -238,7 +238,7 @@ type Device struct {
 	// Path to the device.
 	Path string `json:"path"`
 	// Device type, block, char, etc.
-	Type rune `json:"type"`
+	Type string `json:"type"`
 	// Major is the device's major number.
 	Major int64 `json:"major"`
 	// Minor is the device's minor number.
@@ -256,7 +256,7 @@ type DeviceCgroup struct {
 	// Allow or deny
 	Allow bool `json:"allow"`
 	// Device type, block, char, etc.
-	Type *rune `json:"type,omitempty"`
+	Type *string `json:"type,omitempty"`
 	// Major is the device's major number.
 	Major *int64 `json:"major,omitempty"`
 	// Minor is the device's minor number.