runtime-linux: Drop file-descriptor docs (covered by the command-line…

… API)

It's unclear how these apply to runtimes APIs that are not based on
the command line / execve, and the functionality is covered by the
more tightly scoped LISTEN_FDS wording in the command-line docs.

Signed-off-by: W. Trevor King <wking@tremily.us>

command-line-interface.md

@@ -56,7 +56,7 @@ Start a container from a bundle directory.
 * *Standard streams:* The runtime MUST attach its standard streams directly to the application process without inspection.
 * *Environment variables*
   * *`LISTEN_FDS`:* The number of file descriptors passed.
-    For example, `LISTEN_FDS=2` would mean that the runtime MUST pass file descriptors 3 and 4 to the application process (in addition to the [standard streams][standard-streams]) to support [socket activation][systemd-listen-fds].
+    For example, `LISTEN_FDS=2` would mean that the runtime MUST pass file descriptors 3 and 4 to the application process (in addition to the standard streams) to support [socket activation][systemd-listen-fds].
 * *Exit code:* The runtime MUST exit with the application process's exit code.
 
 #### Example
@@ -105,6 +105,5 @@ $ echo $?
 [posix-encoding]: http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap06.html#tag_06_02
 [posix-lang]: http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html#tag_08_02
 [posix-locale-encoding]: http://www.unicode.org/reports/tr35/#Bundle_vs_Item_Lookup
-[standard-streams]: https://github.com/opencontainers/specs/blob/v0.1.1/runtime-linux.md#file-descriptors
 [systemd-listen-fds]: http://www.freedesktop.org/software/systemd/man/sd_listen_fds.html
 [UTF-8]: http://www.unicode.org/versions/Unicode8.0.0/ch03.pdf

runtime-linux.md

@@ -1,11 +1,5 @@
 # Linux Runtime
 
-## File descriptors
-
-By default, only the `stdin`, `stdout` and `stderr` file descriptors are kept open for the application by the runtime.
-The runtime MAY pass additional file descriptors to the application to support features such as [socket activation](http://0pointer.de/blog/projects/socket-activated-containers.html).
-Some of the file descriptors MAY be redirected to `/dev/null` even though they are open.
-
 ## Dev symbolic links
 
 After the container has `/proc` mounted, the following standard symlinks MUST be setup within `/dev/` for the io.