src_util: add poll module

The poll module adds the Poller object for waiting on mutliple file
descriptors at once. The Pollable trait is introduced so rust objects
can expose a file descriptor useful for polling. An impl for EventFd is
included with this change for testing.

TEST=cargo test
BUG=None

Change-Id: I94fd15a17fe0527c0d29c623badb90668d708689
Reviewed-on: https://chromium-review.googlesource.com/514413
Commit-Ready: Zach Reizner <zachr@chromium.org>
Tested-by: Zach Reizner <zachr@chromium.org>
Reviewed-by: Dylan Reid <dgreid@chromium.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/sys_util/src/lib.rs b/sys_util/src/lib.rs
index a1be658..684ca5d 100644
--- a/sys_util/src/lib.rs
+++ b/sys_util/src/lib.rs
@@ -14,6 +14,7 @@ mod eventfd;
 mod errno;
 mod guest_address;
 mod guest_memory;
+mod poll;
 mod struct_util;
 mod tempdir;
 
@@ -23,6 +24,7 @@ pub use errno::{Error, Result};
 use errno::errno_result;
 pub use guest_address::*;
 pub use guest_memory::*;
+pub use poll::*;
 pub use struct_util::*;
 pub use tempdir::*;