Use proper sshd startup waiting code

Signed-off-by: Jiahao XU <[email protected]>

Author: NobodyXu

.github/workflows/coverage.yml

@@ -30,7 +30,7 @@ jobs:
         uses: taiki-e/install-action@cargo-llvm-cov
       - run: |
           # Wait for startup of openssh-server
-          sleep 15
+          timeout 15 ./wait_for_sshd_start_up.sh
           chmod 600 .test-key
           mkdir /tmp/openssh-rs
           ssh -i .test-key -v -p 2222 -l test-user localhost -o StrictHostKeyChecking=accept-new -o UserKnownHostsFile=/tmp/openssh-rs/known_hosts whoami

.github/workflows/minimal.yml

@@ -30,7 +30,7 @@ jobs:
       - uses: actions/checkout@v2
       - run: |
           # Wait for startup of openssh-server
-          sleep 15
+          timeout 15 ./wait_for_sshd_start_up.sh
           chmod 600 .test-key
           mkdir /tmp/openssh-rs
           ssh -i .test-key -v -p 2222 -l test-user 127.0.0.1 -o StrictHostKeyChecking=accept-new -o UserKnownHostsFile=/tmp/openssh-rs/known_hosts whoami

.github/workflows/test.yml

@@ -30,6 +30,7 @@ jobs:
       - uses: actions/checkout@v2
       - run: |
           # Wait for startup of openssh-server
+          timeout 15 ./wait_for_sshd_start_up.sh
           sleep 15
           chmod 600 .test-key
           mkdir /tmp/openssh-rs

wait_for_sshd_start_up.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+
+set -euxo pipefail
+
+until ssh-keyscan -p 2222 localhost; do
+    sleep 1
+done