crosvm: jailed child processes inherit stderr

By inheriting stderr, logs from minijail and the logging macros can be
seen in the stderr of crosvm, which is convenient for debugging.

BUG=None
TEST=None

Change-Id: I6d6506776add780b243da50e635c25d27a8976ce
Reviewed-on: https://chromium-review.googlesource.com/649952
Commit-Ready: Zach Reizner <zachr@chromium.org>
Tested-by: Zach Reizner <zachr@chromium.org>
Reviewed-by: Jason Clinton <jclinton@chromium.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/src/device_manager.rs b/src/device_manager.rs
index 742346a..6155cf8 100644
--- a/src/device_manager.rs
+++ b/src/device_manager.rs
@@ -9,6 +9,8 @@ use std::io;
 use std::os::unix::io::{AsRawFd, RawFd};
 use std::sync::{Arc, Mutex};
 
+use libc::STDERR_FILENO;
+
 use io_jail::Minijail;
 use kvm::IoeventAddress;
 use sys_util::GuestMemory;
@@ -91,6 +93,7 @@ impl DeviceManager {
 
         // List of FDs to keep open in the child after it forks.
         let mut keep_fds: Vec<RawFd> = device.keep_fds();
+        keep_fds.push(STDERR_FILENO);
 
         let mmio_device = hw::virtio::MmioDevice::new(self.guest_mem.clone(), device)
             .map_err(Error::CreateMmioDevice)?;